Foundations of Chiropractic: Subluxation (1st Edition)

Gattarman

Etlnedby

Meridell. GanePlllan, MA, DC Research Faculty, New York Chiropractic College, Seneca Falls, New York; Former Director, Chiropractic Scien ces, Canadian Memorial Chi ropractic Col lege, Toronto, OntariO, Canada; Former Director, Chiropractic Scien ces , wester n States Chiropractic College, Portlan d , Oregon

with 150 il lustration s

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Copyright © 1995 by Mosby-Year Book, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Permission to photocopy or reproduce solely for internal or personal use is permitted for libraries or other users registered with the Copyright Clearance Center, provided that the base fee of $4.00 per chapter plus $.10 per page is paid directly to the Copyright Clearance Center, 27 Congress Street, Salem, MA 01970. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collected works, or for resale. Printed in the United States of America Composition by Black Dot Graphics, Inc. Printing/binding by Von Hoffmann Press, Inc Mosby-Year Book, Inc. 11830 Westline Industrial Drive St. Louis, Missouri 63146

The authors have made every eHon to ensure the accuracy of the information herein, parricularly with regard to technique and procedure. However, appropriate informa­ tion sources should be consuhed. especially for new or unfamiliar procedures. h is the responsibiliry of every practitioner to evaluate the appropriateness of a particular opinion in the conrext of actual clinical situations and with due consideration

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new

developments. Authors, editors, and the publisher cannOt be held responsible for any rypographical or other errors found in this book.

Library of Congress Cataloging in Publication Data Foundations of chiropractic: subluxation/edited by Meridell. Ganerman p.

cm.

Includes bibliographical references and index. ISBN 0-8151-3543·2

I. Spinal adjustment. I. Ganerman. Meridel I. RZ 265.S64F68 1995

95-9902 CIP

615.5·34-

The ArtIcular lesion

Subluxation Synonyms

dl Synonym

Author

Year

Incomplete articular dislocation

Hubka Pate (Cheshire) Pate Brantingham Watkins Hubka Good Northrup Haldeman Watkins Watkins Watkins (Smith) Wood Brantingham Haldeman Brantingbam Hubka D.ishman (Suh) Boissonaulr, Bass Lohse-Busch Haas, Peterson Sinh Vance, Gamburg Hubka

1990 1992 1993 1988 1968 1990 1985 1975 1975 1968 1968 1968 1984 1988 1979 1988 1990 1985

Dishman

D.algleish D.algleish

1985 1960 1960

Watkins

1968

Siosberg D.algleish Collins Halliday Brantingham Collins Haldeman Watkins

1993 1960

Instability of the posterior ligament complex Intersegmental instability

Intervertebral blocking Intervertebral disrelationship Joint aberration

Joint bind Joint dysfunction Kinetic intersegmental subluxation Kinetic subluxation

Less than a locked dislocation Ligatights Locked facet Locking Manipulable lesion Manipulable joint lesion Manipulable lesion Mechanical disorder Mechanical musculoskeletal dysfunction Metameric dysfunction

Misalignment Motor unit derangement complex Motion restriction Neuroarticular dysfunction Neuroarricular subluxation

NeuroarticuJar syndrome Neurobiomechanical (lesion) Neurodysarthritic (lesion) Neurodysarthrodynic (lesion)

1990 1989 1992 1993 1992 1990

Neurofunctinal subluxation

Neurologic dysfunction Neuromechanicallesion

Neuromuscular dysfaciLitation Orthospondylodysarthritics Osteologic lesion Osteopathic articular lesion Osteopa thic lesion Osteopathic spinal lesion Paravertebral subluxation

Partial fixation

?

1936 1988 1975 1968

1 WhIt'IIn a WDrd

>

9

Subluxation Synonyms "

-..

>

"'~u-.'7"" •• ".--,...

\;.

Synonym

Autho,

Year

Posterior facer dysfunction Primary chiropractic lesion Pseudosubluxation Reflex dysfunction Restriction

Haldeman Gatterman Pate Salem Indust. Good Slosberg Haldeman Pate Dishman Mootz Trostler Watkins Northrup Keating Innes Wark Good Dalgleish Bourdillon Johnson Haldeman Dalgleish Palmer Pate (Harris) Ha ldeman Watkins Hieronymus Faye

1975 1990 1990 1992 1985 1993 1975 1993 1985 1993 1938 1968 1975 1992 1993 1831 1985 1960 1982 1985 1975 1960 1910 1993 1975 1968 1746 1986 1993 1992 1968 1965 1992 1985 1969 1976 1989

Sectional subluxation Segmental dysfunction Segmental vertebral hypomobility Simple joint and muscle dysfunction without tissue damage Slipping sacroiliac joints Soft tissue ankylosis Somatic dysfunction Spinal boo boo Spinal hypomobilities Spinal irritation Spinal joint blocking Spinal joint complex Spinal joint stiffening Spinal kinesiopathology Spinal subluxation Spondylodysarthritic lesions Sprain Stable cervical injury of the spine Static intersegmental subluxation Structural disrelationship Subluxation Subluxation complex Subluxation complex myopathy Subluxation syndrome Total fixation Vertebral displacement Vertebral dysfunction Vertebral dyskinesia Verrebrallocking Vertebral subluxation complex Vertebral subluxation syndrome Modi fied from Rome P, Terrett A. The names in brackers are o riginal autho rs cited by others.

Peterson

Gatterman Watkins Kunert Lirtlejohn Dishman Stoddard Faye Lantz

10 Terminology assessment model

AtIII'8 1-1 The definition allows for physiologic dysfunction, which was described as follows by Harr ison(3) in 1821: When any of the vertebrae become displaced or [00 prominenr, the patient experiences inconvenience

from a local derangement in the nerves of the parr. He, in consequence, is ro rmented with a train of nervous symprol11s, which are as obscu re in their origin as they are stubborn in their nature . ...

Harrison also considered a lignment a nd motion when describing subluxations, and in 1824 he wrote: The articu lating extremities are only partially sepa· rated , nor imperfectly disjoined . ..

and ... the articula r motions arc imperfectly per-

In case of a simple vertebral subluxation, the vertebra is not lodged in a fixed and permanent abnormal position li ke a displaced brick in the wall; (0 consider it so is preposterous for it is a moveable bone in a flexible and moveable co lumn. A simple subluxared vertebra differs from a norma l verrebra on ly in its field of motion, bur because of its being subluxated, its va rio us positions of rest are differently located than when it was a normal vertebra. . . its field of mocion may be roo great in some directions and too sma ll in others.

Within a decade of its inception, the chiropractic profession was arguing over the definition of su bluxation, the primary focus of chiropracric treatment. Was it misalignment, alteted motion, or joint dysfunction? Why not anyone, two, or all three?

formed, because the surfaces of the bones do nO[

fully correspond(3). Although Palmer himself foc used on misalignment in his ea rl y definition of chiropracric, he a lso wrote extensively on the neurologic effects produced by subluxa ri on. In perhaps rhe earliest published chirop ractic text, Modernized Chiropractic(S), autho rs Smith, Langsworthy, and Paxson wrote:

Manipulable and Nonmanlpulable SubluxaUons Not all subluxations respond CO manipulation; in fact, those subluxations most often seen on radiograp hs are often nonmaniplJlable or parhologic subluxa tions that are not reversible or that

11 require surgical repair (see Chapter 8). It is important that when defining subluxation the definition be broad enough ro include the medical concept of subluxation that is severe enough ro be visible on radiograph, as well as the more subrle manipulable subluxation detected by palpation. The manipulable subluxation is further defined as: IIIIIipuIIbIe IIMIxa1Ion a subluxation in which altered alignment, movement, or function can be

The terms subluxation complex and subluxation sy"drome are used as a means of broadening the idea of the effects of subluxation without attaching untested theories to the description of the articular lesion that responds ro manipulation. In any definition, words or phrases that need clarifying mUSt be clearly stated. So it is with the term motio" segment. The need for a term that can be applied ro peripheral joints as well as to spinal joints fostered the following definition:

improved by manual thrust procedures. Moving beyond subluxation as exclusively a joint phenomenon and addressing the complex of neurologic effects theorized to be caused by articular subluxation, the term subluxatio" complex is used. This has been defined as: IIMIxa1Ion _ _ x a theoretical model of motion segment dysfunction (subluxation) that incorporates the complex interaction of pathologic changes in nerve, muscle, ligamentous, vascular, and connective tissues.

The subluxation complex was first described by Faye in the mid 1970s(6). Building on the work of Gillet, IIIi, Homewood, and janse, Faye(6) formulated a theory that the chiropractic spinal adjustment (manipulation) restores normal joint motion, which in turn normalizes physiologic

function. The subluxation complex has been developed further by Lantz(7) and is discussed in Chapter 9. Subluxatioll SYlldrome is the term used ro describe the clinical manifestations of subluxation (articular lesion). Most widely recognized among these syndromes are mechanical back pain, neck pain, and vertebrogenic headaches. Subluxation syndrome is defined as:

.y.......

IIMIxa1Ion an aggregate of signs and symptoms that relate to pathophysiology or dysfunction of spinal and pelvic motion segments or ro peripheral joints. The clinical manifestarions of subluxation syndromes are discussed in Part 3 of this text.

III01IIIn .......1 a functional unit made up of two adjacent articulating surfaces and the connecting tissues binding them to each other. The following definition is mote specifically related ro the joints of the spine:

.... 1IIOIIan .......1 twO adjacent vertebrae and the connecting tissues binding them ro each other. The origin of the functional unjt of the three-joint spinal motion segment comes from junghanns, who coined the term bewegungssegment. The inaccurate translation(8,9) of bewegungssegme"t to "motor segment" by Besemann in 1971(10) was clouded further when the term was modified to "moror unir" and popularized through the proceedings of the NrNCDs monograph, "The Research Status of Spinal Manipulative Therapy," published in 1975(11). The prior use of "motor unit" by physiologisrs ro refer ro a single motor neuron and the group of muscle fibers that it innervares has precipitated the need for clarification of the concept with standardization of the term.

Denning Chiropractic lreatment Methods Chiropractic treatment has been directed traditionally ro the resroration of function and has not been designed solely to relieve pain. just as the primary lesion treared by chiropractors has been subluxation, the primary chiropractic technique has used manual procedures ro treat the body. As with the term subluxation, much confusion and

12 controversy has surrounded the use of terms and

definitions used to describe chiropractic treatment methods. To clarify the procedures used by chiropractors, the terms manual therapy, manipulafion mobilization, and adjustment were subjected to the consensus process. The definitions arrived at are as follows:

niilllllllllllil1 movement applied singularly or repetitively within or at the physiologic range of joint motion, without imparting a thrust or impulse, with the goa l of restoring joint mobility.

J

manuallherapy procedures by which the hands directly COntact the body to treat the articulations or soft tissues .

The term manllal therapy generated little controversy, but it is included because of the lise by some of the terms mallip"latioll and spinal manipulative therapy synonymously with mal1ltal therapy. By using these terms inclusive of manual procedures, mobilization becomes a form of

manipulation. It is necessary CO differentiate manipulation from mobilization because recem studies have indicated the greater effectiveness of thrust procedures (manipu lation ), for example, in the treatment of back pain. Early studies did not make this distinction when producing equivocal data as ro the effectiveness of manipulation. As mo re studies are undertaken, many more may

show different effects from thrust versus nonthrust procedures, making this distinction even more critical. Unknowing patients may assume that they have received manipulation when indeed they have not when mobilization is considered a form of manipulative therapy, thus denying them the possible benefits of thrust techniques. Based on the 1991 RAND study(12) that looked at the appropriateness of spinal manipulation for low-back pain that defined manipulation as a thrust procedure, the following definition reached consensus :

IIIIIIIpIDtIon a manual procedure that involves a ditected thrust to move a joint past the physiologic range of motion without exceeding the anaromic limit. To differentiate manipulation from nonthrust mobilization, the following definition was ag reed on:

Next to the term slIblllxatioll, the use of the word adillstment has sparked the most heated debate. It was agreed that chiropractOrs applying the adjustment intend [0 influence morc than joint mechanics and related pain. The resultant definition that reached consensus therefore includes reference to changes in neurophysiologic function. Although some believed that the adjustment should be restricted to specific short-lever, highvelocity, low-amplitude thrust techniques, it was agreed to define the term broadly enough to not exclude those procedures routinely used by chiropractOrs that fall outside of this narrow category. The resultant definition is as follows:

IItIItment

any chiropractic therapeutic procedure that uses controlled force, leverage, ditection, amplitude, and velocity directed at specific joints or anaromic regions. Chiropracrors commonly use such procedures to influence joint

and neurophysiologic function. The reference to neurophysiologic function in the definition of adjustment and nOt in that for manipulation is not intended to imply that such neurophysiologic effects do not occur with manipulation, that is, thrust procedures. On the contrary, it may be demonstrated that manual thrust procedures through reflex mechanisms produce widespread effects. These mechanisms are the subject of Part 2, in which data are discussed that support Palmer's later contention that [he

body is not a sim ple machine but rather a complex interaction of systems mediated by the nervous system(12) . To those traditionalists who want chiropractOrs to use on ly the term adiustmellt as opposed to manipulatioll, it is noted that D. D. Palmer used the term mallipulatioll to describe his early techniques, and nor until later in the twentieth century was the term adjustment lIsed for Palmer's unique style of manipulation(13 ).

CIIapter 1

What's In • Word

13

Issues 01 Chlropracdc Terminology Unfortunately, when it comes to the word subluxation, too many chiropractors act quite like Humpty Dumpty in Lewis Carroll's Through the Looking Glass: "' . . . When I use a word,' Humpty Dumpty said, in rather a scornful tone, 'it means just what I choose it to mean-neither

more nor less . ... ", Such an attitude toward the use of the word subluxation, as with any term, does nor facilitate communication; as Lawrence(14) has stated that " ... one of the greatest challenges facing the chiropractic profession today is simply to learn how to communicate with one another." He emphasizes the seriousness for the chiropractic profession of miscommunication from semantic confusion, stating, "Semantic difficulties

have hampered our overall development.»

Oppositional TlIinking As with many issues, much of the controversy surrounding the use of the term subluxation has

involved dualism or oppositional thinking by which the phenomenon is either/or but not both . If a subluxation is A, it therefore cannot be B. If I am right, you must be wrong. Examples include those who view a subluxation as an alteration of motion in which the misalignmem component is

nonexistent or at best unlikely, or as a medical term used to describe displacement without joint dysfunction(15) . It seems probable that sublu xation refers to impaired mobility with or without positional alteration. In many cases the misalignment component is not discernible by current technological methods and cannot be used as the sole criteria for subluxation detection. Slighr misalignment cannot be accu ratel y ascertained by analyzing radiographs, and in those cases where misalignment is gross enough to be detectable by plain film radiographs, manipulation may be contraindicated because of excessive motion . As Howe and Phillips(16) have both noted: Any method of spinographic interpreta tion which

utilizes millimetric mensurations from any set of preselected points is very likely ro be faulty, because structurally asymmetry is universal in all vertebrae .

Does this mean that a subluxation must be gross enough to be detectable on radiographs to be identifiable? Some consider that the term sublllxatio" should be reserved for radiographically measurable positional disrelationships of joint surfaces. Others suggest that subluxation should be reserved for static positional relationships measured in in vitro investigations(17). For 100 years have chiropractors been treating a lesion detectable on ly in vitro? Yet others claim that subluxation has not been measured in any case. At the extreme, if a subluxation is a misalignment, then it is not motion restriction but rather a vertebra out of place. Alternatively, the subluxation is viewed as a motiory restriction, and no component of malposition should be considered. This is attractive to some, given the current lack of sophistication of methods available to consistently detect spacial disrelationships radiographically; logic leads us to conclude that we are dealing with a functional entity involving restricted vertebral movement. Rationally, it is the movement restriction component of the manipulable subluxation that responds to thrust procedures, yer reliable measurement of motion remains as elusive as radiographic detection of subtle misalignment. Does this mean that pain is the sole reliable criterion for detection of subluxation? What of nonmanipulable subluxation with excess motion and instability? Is it not painful? This brings us full circle and leads to a definition of subluxation in which all three components of the subluxation should be considered:

1. Misalignment or spatial relationship 2. Excessive or restricted motion 3. Dysfunction with or without pain

14

Subluxation

Tbe AI'tIcuIar Laslon

One component should not be used to describe or de tect a subluxation to the exclusion of any other, nor must all three components be present. Similarly, we saw that the prechiropractic use of the word subluxatioll included slight change in posi-

tion of the articulating bones, lessened motion of the joints, and pain . Why then must we now relegate the term subluxatioll to a lesion with only one of the early distinguishing features?

Issues Surrounding the Use 01 the Word Subluxation Historical Issues Early chiropractic terminology became distinctive to differentiate the new profession from both osteopathy and medicine. Whereas the osteopath manipulated the osteopathic lesion, the chiropractor manipulated (and later adjusted) the subluxation. D. D. Pa lmer sought to differentiate chiropractic from osteopathy, probably in response to charges of having stolen ideas from the founder, Still(18). The distinction that chiropractors do nor diagnose symptoms and trear d.isease,

rather they analyze the spine and adjust subluxations, although a successful legal defense, has led to much isolation and great misunderstanding of the chiropractic profession.

The Philosophical Issue T he use of the word subluxation as a metaphor has created a phi losophic issue whereby subluxatioll becomes like the medical use of the word disease, the eradication of which resto res the homeostasis of the body and eliminates all human ailments(19) . Although it remains to be conclusively demonstrated that, as

Harrison wrote in 1820, "an almost infinite variety and endless complication of nervous symptoms" may be the effects of subluxation, this theory must be kept in perspective, examined, and tested. Criticism of the va lidity of this basic premise must nOt be auromacically rejected as an attack on the chiropractic profession but viewed as a cha llenge to be met. Evidence that supports the va lidity of the theory espoused by Palmer(20) that subluxations cause functional changes in the

nervous system is presented in the following chapters. Emotional and unbending adherence to this construct by some without crideal evaluation

has polarized the profession. The notion that subluxation is the cause of all disease is not rationa ll y defensible and has caused much derision of the chiropractic profession to be brought on by dogmatic proponents of this theory(21). Evidence must be evaluated and integrated where rational to support the principles of chiropractic theory.

The Political Issue The political controversy surrounding the use of the word subluxatioll stems from the medical influence that adds the qualification that visual evidence of subluxation must be demonstrated on radiographs(22). This is nOt stated, however, in the following dictionary definitions of subluxation:

1. Subluxation: A partial dislocation(23 ) 2. Subluxation: Partial dislocation (as of one of the bones in a joint)(24) 3. Subluxation: An incomplete or partial dislocation(25) 4. Subluxation: A partial or incomplete dislocation(26) 5 . Subluxation: An incomplete luxation or dislocation; though a relationship is altered, contact between joint surface remains(27)

Yet radiographic visualization of a subluxation is the criteria for reimbursement of the treatment of

subluxations by chiropractors under the United

1 WhaflIn a WOI'd States Medicare and Medicaid Acts. Because the reliability of radiographic detection of manipulable subluxations has been questioned, some believe that by abandoning the term this issue can be sidestepped . What then of Medicare and Medicaid coverage of chiropractic patients? The emotional response of some with regard to this politica l issue again stems from the derision of chiropractic that comes from those who deny the existence of manipulable lesions on the grounds that they are nor consistently seen on radiographs. Rather than falling prey to this political ploy, we must clearly determine and agree on the crireria used to detect manipulable subluxations, which is the primary issue surrounding the subluxation as

a clinical entity. We are once again polarized by those who wish to abandon the term on the basis of medical territoriality that requires radiographic detection and those who cling to dogmatic philosophic beliefs. Medical use of the rerm subluxation for the lesion that responds to manipulation, as we have

noted, existed before the advent of radiographs(3) and continues to be used in this manner. Examples are: "Sacroiliac subluxation " implies that ligamentous stretching has been sufficiem to permit the ilium to slip o n the sacrum. An irregu lar prominence on

one articu lar surface becomes wedged upon another prominence of the other articular surface, the ligaments are taut, reflex muscle spasm is inten se, and pain is severe and conrinuous uneil reduction is effected. The displacement is so slight that it cannot be recognized in roentgenograms ... . The pain of subluxation is often relieved dramati-

cally and suddenly by manipulation(28). and Subluxated Facet Joint: The facet syndrome, which can cause severe back pain, consists of a subluxarion or partial dislocation of a lumbar vertebral facet joint. This is rhe condirion most likely to be relieved when a chiropractor manipulates [he

spine(29). It is apparent that medical use of the term subluxation when referring to the lesion treated by

15

manipulation does not require radiographic evi-

dence to support the existence of this clinical entity. A more reasonable solution seems to be a

classification of subluxation in which the most severe are seen on radiographs and are nOt

a lways amenable ro manipulation. The less extreme lesions, which are sti ll subluxations of a lessor degree, are nonetheless articular lesions, but less so than dislocations and, in many cases,

manipulable subluxations.

Clinical Issues As previously noted, rhe method of detection is the primary clinical issue su rrounding the sublu xation concept. It is ironic that an effective method of treatment has existed for centuries, yet there is no common agreement on the criteria

used to detecr the lesion ro be treated. Various palpation procedures have been developed, which has been the traditional method used to detect subluxation; yet these merhods are under crirical attack for poor interrater reliability. Difficulty arises i;' describing palparory procedures because we use one-d imensional language to conceptualize a three-dimensional abstraction. Diagnosis of

the manipulable subluxation is dependent on the kinestheric perception of the palpating chiropractor, which is more akin to reading braille: threedimensional and difficult to translate verbally. This phenomenon, which may account for the greater intra rater reliability than interrater relia bility, must be better understood if we are to further improve rhe chiropracror's diagnostic predictability. This issue is addressed further in Chapter 4. The dogma and irrationa li ty exhibited by some regarding the derection of subluxation is embodied in the following quote: «A chiropractic case is one with a sublu xation . . . . We take a case even though ou r insr.rumentation doesn't show a

subluxation because we know it's there"(30) It is reasonable and rational to objectively determine the most reliable method of detection of subluxations rather than to continue to argue over which

16 method of detection is most effective. The detection of subluxations has given tise to a multitude of technique systems that apply a cookbook approach to diagnosis of chiropractic disorders. These include muscle testing, leg length checks, and finite radiographic marking procedures. The medical criterion of using pain syndromes as the criteria for manipulative therapy is an abandonment of the specificity that chiropractic diagnosis has employed in analyzing mechanical disorders of the spine. It does not rationally account for the pain produced by nonmanipulable subluxations, which cannOt be differentiated by using pain as the primary diagnostic criteria.

Economic Issues Perhaps the most damaging of all issues, considering today's economy and the escalating cost of health care, is the overtreatment of subluxations charged to third-party payers. Ongoing treatment of subluxations attributable to work-related and personal injuries, which in most cases have long

since healed, strains the credibility of the chiropractic profession. It is imperative that chiropractors differentiate between the subluxation leading ro joint dysfunction and tissue abnormalities. Simple subluxations, exhibiting restricted motion only, respond rapidly, in one or rwo treatments, to manipulation. More seriously injured joints,

with injured holding elements and accompanying surrounding soft tissue damage, take much longer to heal. It is essential that the chiropractor make two types of assessment. The first is a biomechanical analysis to determine the site and nature of the subluxation . This determines where and whether manipulation and other adjustments are appropriate. The second form of assessment is a diagnosis necessary to ascertain the extent of pathologic damage and ro determine the type of adjunctive thetapy that will hasten the healing process. The first diagnosis (biomechanical analysis) is necessary to determine the functional component of the patient's coodinon, whereas the second diagnosis gives the patient's prognosis with regard to healing time. Both the functional

and pathologic diagnoses must be considered and recorded as parr of ethical and legal records and are necessary when seeking insurance reimburse-

ment(31 ).

Conclusion The establishment of any profession requires terminology unique to that profession. Unless chiropractic would become ancillary to medicine as is physical therapy; or co-opted and included in medical practice as is osteopathy, it is imperative

that the chiropractic profession continue to develop and maintain its distinctive nomenclature. This is nOt to say that chiropracrors should cling to outdated concepts and ambiguous terms. It is incumbent on the chiropractic profession to come to consensus whereby key terms used to describe chiropractic procedures and practices are used universally. The chiropractic profession has long enjoyed clinical legitimacy. If we are to move into the realm of scientific legitimacy, we must operationally define the terms we use for the methods we employ. Chiropractors do not have to be adversarial to medicine. Practically speaking, the chiropractic profession is not an alternative form of medicine,

but, like acupuncture, homeopathy, and naturopathy, is complementary to current medical practice. Chiropractic science is considered a poorly organized science by many. The first step in the organization of any science is the establishment of nomenclature that is widely recognized and accepted . What is in the word subluxatloll? The chiropractic subluxation is a more subtle lesion than the radiographically recognized medical subluxation. For thousands of years before the advent of x-rays, manipulation was employed to alleviate pain and loss of function from joint lesions less than a luxation or complete dislocation. For 100 years chiropracrors have been successfully diagnosing and treating manipulable subluxations, relieving much human suffering. A foundation of the chiropractic profession is the primary lesion treated with manual therapy: the subluxation.

1 WIIIt'1In • WUI'd

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AJCM 1988; I, I 07-9. 2. Haldeman S. In: Inglis 80, Fraser B, Penfield SR. Chiro· practie in New Zealand: Repo(( of the Commission of

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........ Anatomy Related to Spinal Subluxation Gregory D. Cramer

SUsan A. Darby

KeyWOrds

Zygapophyseal joint, intervertebral disc, intervertebral foramen, radicular pain

After reading this chapter yOIt should be able to answer the following questions:

Quesllon #1

What structures form the boundaries of the intervertebral foramen (IVF)?

Question #2

What is radicular pain?

QueSUIII #3

How might treatment of a subluxation decrease somatic referred pain?

19 a vascular central layer made lip of areolar cissue and loose connective tissue, and an inner layer

T

he relationship between the anatomic com-

ponents of the spinal motion segment is criti-

cal to understanding the spinal subluxation model. This three-joint complex consisrs of the two zygapophyseal (posterior) joints and the (anterior) intervertebral disc. These structures interact to

form the funcrional unit of the spine. The position of the intervertebral foramen provides a significant boundary between the central nervous system and the peripheral nervous system, and in some cases it may

be

structurally important to nociceprion aris-

ing from the spinal motion segment (subluxariongenerated pain). Pain of spinal origin is transmitted through peripheral and central neural structures and is modulated at various sites.

consisting of a synovia l membrane (3). The anterior and medial aspect of the Z-joint is covered by the ligamentum flavum. The synovial membrane lines the articular capsule, the ligamentum flavum (4), and the synovial joint folds (see following discussion), but not the articular cartilages of the joint surfaces (1). The Z-joint capsules throughout the vertebral column are thin and loose and are attached to the margins of the opposed superior and inferior articular facets of the adjacent vertebrae (5). Superior and inferior protrusions of the joint capsules, known as recesses, bulge out from the tOP and bottom of the joint. These recesses are filled with adipose tissue, and the inferior recess is

The Zygapophyseal Joints

larger than the superior recess (6). The capsules are longer and looser in the cervical region than in the lumbar and thoracic regions. This is to

General DescMpUon

compensate for the greater amount of movement that occurs in this region. As mentioned previ-

The junction between the superior and inferior articular faccts of the articular process

(zygapophyses) on one side of two adjacent vertebrae is known as a zygapophyseal joint (Z-joint). These joints are also referred to as facet joints or inter/aminar joints (I). The Z-joints are classified as synovial (diarthrodial) planar joints. Of course, there is a left and right Z-joint between each pair of vertebrae. They are rather small joints, and although they allow motion to occur, they are perhaps more important because of their ability to determine the direction and limitations

ously, the anteromedial aspect of the joint is formed by the ligamentum flavum (4), and hyaline cartilage covers the surface of each facet.

Tbe Zygapophyseal Joint Synovial Folds

The Z-joint is of added interest to those who

Zygapophyseal joint synovial folds are synoviallined extensions of the capsule that protrude into the joint space to cover part of the hyaline cartilage. The synovial folds vary in size and shape in the different regions of the spine. Engle and Bogduk in 1982 (7) reported on a study of 82 lumbar Z-joints (cervical folds are discussed later). They found at least one intraarticular fold (meniscus) within each joint. The

treat spinal conditions because, as is the case in any joint, loss of motion or aberrant motion may

three types: The first was described as a connec-

be a primary source of pain (2).

tive tissue rim found running along the most

ArtIcuI.. capsules

tive tissue rim was lined by a synovial membrane.

Each Z-joint is surrounded by a capsule posterolaterally (Figure 2-1). The capsule consists of an

The second type of "meniscus" was described as an adipose tissue pad, and the third type was identified as a distinct, well-defined, fibroadipose meniscoid. This latter type of meniscus was usually found entering the joint from the superior or inferior pole of the joint (or both).

of movement that can occur between vertebrae.

intraarticular Structures were categorized into

peripheral edge of the entire joint. This connec-

outer layer of dense fibroelastic connective tissue, Adapted from Cramer C, Darby S. Basic and clinical anammy of (he spine, spinal cord, and ANS. St. Louis: Mosby, 1995.

20

Z joint

A

Z joint

--- -

--- lumbar

fIIIpe 2·1 The zygapophyseal joint showing the layers of the articular capsule. A, Typical zygapophysea l joints of each vertebral region. B,

Typical zygapophyseal joint. The layers of the Z·Joint as seen in parasagirtal section (inset) are color coded as follows: light blue, joinr space; dark blue, articular cartilage; brown, subchondral bone; red, synovial lining of articular cartilage; pink, vascularized, middle layer of the articular capsule; violet, fibrous outer layer of the articu lar capsule. (From Cramer, Darby. Basic and dinical anatomy of the spine, spinal cord, alld ANS. St. LOllis: Mosby, 1995.)

.=.--+--

s..bchondoal

bone

• Giles and Taylor (3) studied 30 zygapophyseal joints, all of which were found to have "menisci." The "menisci" were renamed zygapophyseal joint

synovial folds because of their histologic makeup. Free nerve endings were found within the folds, and the nerve endings met the criteria for pain

21 receptOrs (nociceptOrs). That is, they were distant from blood vessels and were of proper diameter (6 to 12 ~ms) . Therefore, the synovial folds or menisci themselves were thought to be pain sensitive. This meant that if the Z-joint synovial fold became compressed by or trapped between the articular facets making up the Z-joint, back pain could resulr.

IJnIque Characteristics 01 the cervical Zygapopltysaal J«*rts The cervical Z-joints lie approximately 45° to the horizontal plane (8). More specificaliy, the facet joints of the upper cervical spine lie at approximately a 35° angle to the horizontal plane, and the lower cervical Z-joints form a 65° angle to the horizontal plane (9). The superior articular processes and their hyaline cartilage-lined facets face posteriorly, superiorly, and slightly medialiy. The appearance of rhe cervical Z-joints changes significantly with age. Before the age of 20 years the articular cartilage is smooth and approximately 1 to 3 mm thick, and the subarricular bone is regular in thickness. The articular cartilage thins with age, and most adult cervical Z-joints possess an extremely thin layer of carrilage wirh irregularly thickened subarricular cortical bone. These changes of articular cartilage and the subchondral bone usually go underected on magneric resonance imaging and computed tOmography scans. Osteophytes (bony spurs) projecting from the arrieular processes and sclerosis (thickening) of the bone within the arricular processes are quite common in adult cervical Z-joints.

Cervical ZygapophY8ea1 Joint Synovial Folds Zygapophyseal joint synovial folds (menisci) project into the Z-joints at all levels of the cervical spine. Yu et al. (10) found four distinct types of cervical Z-joint menisci, ranging from thin rims to thick protruding folds. Yu et al. demonstrated several types of folds on magnetic resonance imaging scans.

marvallon 01 the Z-JoInt8 The Z-joint capsule receives a rich supply of sen-

sory innervation. The sensory supply is derived from the medial branch of the posterior primary division (dorsal ramus) at the level of the joint, and each joint also receives a branch from the posterior primary division of the level above (Figure 2-2). In addition, Wyke (11) states that there are three types of sensory receptors in the joint capsule of the Z-joints. These are as follows :·

type I very sensitive static and dynamic mechanoreceptOrs, which fire continua ll y to some extent even when the joint is not moving

type I

less sensitive and fire only during move-

ment

Mixed spino I nerve Posterior primary

division (dorsal ramus) Anterior primor'( division (ventra ramus)

lateral branch of PPO Medial branch of PPO

Ascending division Descending division

Agtre 2-2 Innervation of the zygapophyseal joints. Notice each posterior primary division (dorsal ramus)

divides into 3 medial and lateral branch. The medial branch has an ascending division which supplies the Zjoint at the same level and a descending division which supplies the Z·joint immediately below. (From Cramer, Darby. Basic and clinical anatomy of the spine, spinal cord, and ANS. 51. LOllis: Mosby, 1995.) ·Note char type Ulare nociceptive fibers found in joints of (he extremities, and Wyke (10) did nOt find these in the Z·jolnts.

22

SublUXallon

The Ar1IcuIr 18110n

type IV slow conducting nociceptive mechanoreceprors

The Intervertebral Disc The intervertebral disc (!VO) is composed of water, cells (primarily chondrocytelike cells and fibrob lasts), proteoglycan aggregates, and collagen fibers. The proteoglycan aggregates are composed of many proteoglycan monomers attached to a hyaluronic acid core. Howeve~ the proteoglycans of the lVD are of a sma ller size and are of a different composition than the proteoglycans of cartilage found in other regions of the body (articu lar cartilage, nasal carti lage, cartilage of growth plates) ( 12) . The lVO is a dynamic structure that has been shown to be able to repait itself and is capable of "considerable" regeneration (13). The !VO is composed of three regions known as the anulus fibrosus, the nucleus pu lposus, and the vertebral (cartilage) end plate (Figure 2-3). Together they make up the anterior interbody joint or intervertebral symphysis. Each of these regions consists of different proportions of the pri mary materials that make up the disc (see previous discussion) .

Anulus Abrosus The a nulus fibrosus is made up of several fibrocarti laginous lamellae or rings, which are convex

externally. The lamellae are formed by closely arranged collagen fibers and a smaller percentage (10% of the dry weight) of elastic fibers (14). Most of the fibers of each lamella run parallel with one another at approximately a 65° angle from the vertica l plane. The fibers of adjacent lamellae overlie each other, forming approximately a 130° angle between the fibers of adjacent lamellae. The most superficial lamellae send thick bundles of collagen into the bone of the vertebral rims in the region of the ring apophysis. These bundles are known as Sharpey's fibers. They form firm attachments between the intervertebral discs and the vertebral body. The inner lamellae of the anulus fibrosus attach ro the cartilaginous vertebral end plate. The direction of the

..... 2-8 MRl of a sagittal section of the intervertebral disc with adjacenr vertebral bodies. The parts of the intervertebral disc are labeled (Photograph by Ron Mens ching, illustration by Dino Juarez. The National College of Chiropractic. (From Cramer. Darby. Basic and clinical spinal anatomy o f the spine,

spillal cord, alld ANS. St. LOllis: Mosby, 1995)

lamellae varies considerably from individual ro individual and from one vertebra ro the next (15 ). The lamellae of the anulus fibrosus are subject ro tear. These rears occur in two directions, cit-

cumferentially and radially. Many investigators believe that ci rcumferential tears are the most

common. This type of tear represents a separation of adjacent lamell ae of the anu lus. The separation may cause the lamellae involved to tear

away from their vertebra l attachments. The sec-

23 ond rype of rears are radial in direcrion. These run from rhe deep lamellae to the superficial layers. Mosr aurhors (16) believe rhar rhese types of rears develop after circumferenrial rears and rhar the presence of circumferential tears make it easier for radial tears ro occur because radial rears are able to connect severa ) adjacent circumferen-

tial rears. When this occurs the inner nucleus pulposus may be allowed to bulge or even extrude into rhe ve rtebral canal. This is known as intervertebral disc protrusion (bulging) or herniarion (extrusion ). However, this scenario probably occurs much less frequently rhan was once believed.

Ib:Ieua P..... The nucleus pu lposus is a rounded region located wirhin rhe center of rhe IVD. Ir develops from rhe embryologic notochord. The nucleus pulposus is gelatinous and relatively large just after birth, and several mulrinucleared notochordal cells can still be found within irs subsrance (5). Except for the most peripheral region of the anu lus fibrosus, the disc is an avascular structure, and the nucleus pulposus is responsible for absorbing most of rhe fluid received by rhe disc. The process by which a disc abso rbs its fluid from rhe vertebral bodies above and below has been rermed imbibition. When a load is applied to the spine, an IVD loses water but retains sodium and potassium. This increase in electrolyte concentration creates an osmotic gradient that resu lts in

rapid rehydrarion when rhe loading of the disc is stopped (17). The disc appa rently benefits from borh activity during the day and the rest it receives during rhe hours of sleep. As a resulr, rhe disc is thicker (from superior ro inferior) after rest than after a typical day of sitting, standing, and walking. Too much rest may nor be beneficial, however. A decrease in the amount of fluid (hydration) of the intervertebral discs has been noted on magnetic resonance imaging scans after

5 weeks' bed rest (18) . The disc reaches its peak hydration at app roximately the age of 30 years, and the process of degeneration begins shortl y thereafter (19). As rhe disc ages it becomes less gelatinous in consistency, and its ability to absorb

fluid diminishes. The aging changes in composition and structure, which are common to all sources of cartilage, occur ea rlier and to a

grearer extent in rhe rYD (20) . Breakdown of the proteoglycan aggregates and monomers is thought to contribure to rhis process of degeneration . Breakdown of proteoglycan resu lts in a decreased ability of rhe disc to absorb fluid, which, in rurn, leads to a decrease in rhe abil ity of rhe disc to resist loads placed on it. The degenerarion associated with rhe decrease in ability to absorb fluid (water) has been identified with computed romography (2 1) and magneric resonance imaging, and has been correlated wirh histologic strucrure and fluid con rent. As the disc degenerates, it narrows in the superior to inferior dimensions, and the adjacent vertebral bodies may become scleroric (rhickened and opaque o n radiographs). Much of the disc thinning seen with age may also be the result of the disc "sinking into" rhe adjacent vertebral bod ies over the course of many years (15). Pathology of the intervertebral disc is seen rarher frequent ly in clinical practice. As mentioned previously, the nucleus pulposus may cause bulging of the outer anular fibers or may prorrude (herniare) rhrough the a nulus. This was first described by Mixter and Barr (22). Bulging o r herniation of the disc may be a primary source of pain, or pain may resu lt from pressure on the exiting nerve roots within the vertebral or

inrervertebra l foramen. Such bulging is usua ll y associated with trauma, although a history of rrauma may be absen t in as many as 28% of patients with confirmed disc protrusion (23) . Some investigarors believe thar proreoglycan leaking o ut of a tear in the anu lus also may cause pain by creating a chemical irriration of the exiting nerve roots. Pain caused by pressure on or irritation of a nerve root radiates in a dermaromal pattern. Such pain is termed radicular

pail! because of its origin from the dorsal root (radix) or dorsal root ganglion. Treatment for hern iation of the nucleus ranges from conserva-

rive methods (24 ) to excision of the disc (discectomy) to chemica l degradation of rhe disc (chymopapain chemonucleolysis) (25, 26).

24

Vertebral End Plata Vertebral end plates are carrilaginous plates that limit the disc (with the exception of the mOSt peripheral rim) superiorly and inferiorly and are artached to the nucleus pulposus, anulus fibrosus, and ro the adjacent verrebral body. Although a few authors consider the verrebral end plate to be a parr of the verrebral body, most authorities consider it to be an integral porrion of the disc (18, 26). The end plates are approximately 1 mm thick peripherally and are thicker centrally. They are composed of both hyaline carri lage and fibrocartilage. The hyaline carrilage is located against the vertebral body and the fibrocartilage is found adjacent ro the remainder of the intervertebral disc. The end plates help to prevent the verrebral bodies from undergoing pressure atrophy and, at the same time, contain the anulus fibrosus and nucleus pulposus within their normal anatomic borders. Occasionally the nucleus pulposus ruptures through the verrebral end plate, causing a lesion known as a Schmorl's node. These nodes cause the verrebrae surrounding the lesion ro move closer together. This movement is thought ro increase pressure on the anterior joints between the verrebrae, speeding the degenerative process of the anterior inter body joint (by means of internal disc disruption). In addition, the disc thinning or narrowing that results from these end plate herniations leads to more force being borne by the Z-joints, which may result in more rapid degeneration of these structures as well . The vertebral end plates begin to calcify and thin with advancing years. This leaves them more brittle. The central tegion of the end plate in some verrebrae of cerrain individuals may be completely lost in the later years of life.

innervation

0' Intervertebral lilacs

The outer third of the anulus fibrosus of the interverrebral discs has been found ro receive both sensory and vasomoror innervation (28). The sensory fibers are probably both nociceptive (pain sensitive) and proprioceptive in nature, and the vasomoror fibers are associated with the small vessels located along the superficial aspect of rhe anulus fibrosus. The posterior aspeer of the disc

receives its innervation from the recurrent meningeal nerve (sinuverrebral nerve). The posterolateral aspect of the anulus receives both direct branches from the anterior primary division and also branches from the gray communicating rami of the sympathetic chain. The lateral and anterior aspects of [he disc primarily receive their innervation from branches of the gray communicating rami and also from branches from the sympathetic chain (Figure 2-4). The fact that the disc has direct nociceptive innervation is very clinically relevant. The intervertebral disc itself is probably able to generate pain. Therefore, disorders affecting the intervertebral discs alone, such as internal disc disruption and tears of the ourer rhird of the anulus fibrosus, can be the sole cause of back pain. The disc also can generate pain by compressing (entrapping) an exiting dorsal root. Also, leakage of nerve-irritating (histaminelike) molecules from disrupted intervertebral discs has been found to be a cause of irritation ro the exiting dorsal root. These larter conditions cause a sharp, stabbing pain that radiates along a dermaromal pattern. This type of pain is known as radicular pain because it results from irritation of a nerve rOOt (radix).

CarvlcallntarvlrtebrallHscs The basic anaromy of the cervical interverrebral discs is similar to that of interverrebral discs throughout the spine. The discs of this region make up more than 25 % of the superior to inferior length of the cervical spine and help ro allow for the large amount of motion that occurs in this region. The intervertebral discs in the cervical region thin as one ages, while at the same rime, the uncinate processes continue to enlarge. As a result, by the age of 40 years the uncinate processes create a substantia l barrier that prevents lateral and posterolateral herniation of rhe intervertebral disc. Therefore, Bland (29) believes that the cervical discs dehydrate earlier in life than do the discs in the thoracic and lumbar regions. In fact, he states that there is no nucleus pulposus in the cervical spine beyond the age of 45 years, and therefore he believes that intervertebral disc protrusion has been overdiagnosed in

2 Anatomy RaIIted to SpInal SUbluxation

25

f1111'12-4 The innervation of the intervertebral disc in horizontal section . The neural elements have been drawn onto a horizontal magnetic resonance imaging scan. The tOP of the illustration is anterior and the bottom is posterior. Numbers indicate the following: 1, sympathetic ganglion; 2, gray ramus communicantes; 3, branch of the gray ramus coursing toward the inrervertehral foramen (JVF) ro contribute to the

recurrent meningeal (sinuverrebral) nerve; 4. anterior

primary division (ventral ramus); 5, medial branch of posterior primary division (the lateral branch is seen coursing ro the right of the medial branch in this illustration); 6, dorsal root (spinal) ganglion and dural root sleeve (red) within the IVFi 7, recurrent meningeal (sinuverrebral) nerve; 8, cauda equina (yellow) within

the cerebrospinal fluid (blue) of the lumbar cistern of the subarachnoid space; 9, zygapophyseal joint. Notice the intervertebral disc is receiving innervation from branches of the sympathetic ganglion (anteriorly), gray communicating ramus (laterally and posterolaterally), and the recurrent meningeal nerve (posteriorly). Also notice that the zygapophyseal joint is receiving innervation from the medial branch of the posterior primary division. (From Cramer, Darby. Basic and clinical anatorny of the spine, spinal cord. and ANS. St. Louis: Mosby, 1995. Photograph by ROil Mellschillg, illustration by Dina Juarez. The National College of

Chiropractic.)

the cervical region . Recall that there are no intervertebral discs between the occiput and the atlas or between the atlas and the axis. The C2-C3 interbody joint is the first such joint to possess an intervertebral disc. Therefore, the C3 spina l nerve is the most superior nerve that is able to be affected by possible disc protrusion. Mendel et al. (13) studied the innervation of the cervical intervertebra l discs and found sensory nerve fibers throughout the anu lus fibrosus. These fibers were mOSt numerous in the middle (from superior to inferior) third of the disc. The structure of many of the nerve fibers and their end receptors was consistent with those that transmit pain. In addition, pacinian corpuscles and Golgi tendon organs were found in the posterolateral aspect of the disc. These findings help to confirm

that the anu lus fibrosus is a pain-sensitive structure and further indicate that the cervica l discs are involved in proprioception, enabling the central nervous system to moniwr the mechanical status of the interverrebral disc. Mendel et al. (13) hypothesized that the arrangement of the nerve fiber bundles may a llow for the IVD to sense periphera l compression o r deformation as well as alignment. No nerves were found in the nucleus pulposus (13).

The Intervertebral ForaRlen The intervertebra l foramen (fVF) is a very important "hole" of the spine. T he fVF is an area of great biomechanical, functional, and clinical significance (5). Much of its imporrance stems from

26

Subluxation The ArtIcU' LIIIIon

the fact that the IVF provides an osteol igamentous boundary between the central nervous system and the peripheral nervous system. Therefore, knowledge of the specific anatomy of this clinically important area is important in the differential diagnosis of back and extremity pain and can help with the proper management of individuals with compromise of this region. A pair (left and right) of intervertebral foramina are located between all of the adjacent vertebrae from C2 to the sacrum . There are no [VFs between C1 and C2. When present, the lYFs lie posterio r to the vertebral bodies and between the superior and inferior vertebra l notches of adjacent vertebrae. Therefore, the pedicles of adjacent

The [VFs are smallest in the cervical regIon, and generally there is a gradual increase in IVF dimensions to the fourth lumbar vertebra . The lYFs between L5 and 51 are unique in size and shape. As mentioned previously, the lYFs are actually canals, varying in width from approximately 5 mm (31) in the cervical region to 18 mm (32) at the L5-51 level. Many structures (surrounded by adipose tissue) traverse the lVF (Figure 2-5). They are as fo llows:

vertebrae form the " roof" and "floor" of this region. The width of the pedicles gives depth to

mental arrery---one to the posterior aspect of

these openings, making them actually neural canals (30) rather than foramina, but the name remams.

5ix structures form the boundaries of the lVF (Figure 2-5). Beginning from the most superior border (" roof") and continuing anterio rl y in a circular fashion, the boundaries are as follows :

1. 2. 3. 4.

The mixed spinal nerve The dural roor sleeve Lymphatic cha nnel(s) Three branches of rhe spinal ramus of a seg-

Epidural adipose Intervertebral ti ssue

vein

Spinal branch of lumbar segmental artery

Tronsforaminal ligament

1. The pedicle of the vertebra above (more specifically, its periosteum ) 2. The vertebral body of the vertebra above (again, its periosteum) 3. The intervertebral disc (posterolateral aspect of the anulus fibrosus ) 4. The vertebral body of the vertebra below, and in the cervical region, the uncinate process

(periosteum) 5. The pedicle of the vertebra below forms the "floor" of the lYF (periosteum ). A sma ll part of the sacral base (between the superiot articular process and the body of the 51 segment) forms the floor of the L5-51 lYE 6. The zygapophyseal joint (forms the " posterior wall" ). Recall that the Z-joint is made up of (1) the inferior articular process (a nd facet) of the vertebra above, (2) the superior articular process (and facet) of the vertebra below, and

Ventral and dorsal

lymphatic

Recurrent

nerve roots within dural root sleeve

channel

meningeal nerve

figure 2-5 The inrervertebral foramen (IVF). Notice the structures that normally traverse the IVE The most

(3) the an terior "articular capsule", which is

common locations of the rransforaminalligamenrs are also shown on this illustration. (From Cramer. Darby. Basic and clinical anatomy of the spine, spinal cord, and AN5. St. Louis: Mosby, 1995. Photograph by Ron Mensching, illustration by Dino Juarez, The National

composed of the ligamentum fla vum (1, 4).

College of Chiropractic.)

2 Anatomy Related to SptnaIlIIII*IxaUon rhe vertebral body, one to the posterior arch, and one ro rhe mixed spinal nerve (neural branch) 5. Communicating veins between the internal and externa l vertebral venous plexuses 6. Two ro four recurrent meningeal (sinuverrebral ) nerves The dorsal and ventra l roOts unite to form the mixed spina l nerve in the region of rh e lYE The mixed spinal nerve is surrounded by the dural roOt sleeve, and the dural rOOt sleeve is attached to the borders of the IYF by a series of fibrous bands. T he dural rOOt sleeve becomes continuous with the epineurium of the mixed spina l nerve at the latera l border of the lYE The a rac hnoid blends with the con nective tissue of the nerve root proximal to the dorsal root ganglion and at an eq uiva-

lent region of the ventral root. Occasiona ll y the arachnoid extends more distally, and in such cases the subarachnoid space extends to the lateral third of the lYE Each recurrent meningeal nerve (sinuve rtebra l nerve of Yon Luschka) origi nates from the mOSt proximal portion of the ventral ramus. It receives

a branch from rhe nearest gray communicating ramus of rhe sympathetic chai n before traversing the lYF. This nerve provides sensory innervation (including nociception) to the posterior aspect of the a nul us fib rosus, the posterior longitudina l ligament, anterior epidu ral veins, periosteum of rhe posterior aspect of the vertebral bodies, and the anterior aspect of the spi na l dura mater. Usually severa l recurrent meningeal nerves enter the same lYE

Accessory Ugaments 01 Ute IVF Golub and Silve rman (33) first used the term Iralls(oramil1a i ligamellt (TFL) when describing a ligamentous band seen to cross the IVF at any level of the spine. These ligaments vary considerably in size, shape, and location from one IYF to anothe r. They found that the spinal arteries and veins ran above this structure and the anterio r primary division ran underneath it. Bachop and Janse (33) reported that the

27

higher the ligament is placed, the less space remains for the spinal vessels, which cou ld conceivably lead [0 ischemia or venous congestion . The lower the ligament is placed, the greater the possi bility of sensory and/or mOtor deficits. Bacho p and Hilgendo rf (35) studied 15 spines and from these they dissected the lum bar lYFs on both the left and the ri ght sides, making a total of 150 lYFs. From these dissections they found the foll owi ng: 26 (17.3%) lYFs had TFLs 13 (50%) of TFLs were at LS-Sl and 11 (73.3%) of the 15 spines had 1 to 2 TFLs at LS-S l 2 (13 %) had 1 to 2 TFLs at LS-Sl

The term corporotransverse liga men t is used when referring to a ligament that runs between the ve rtebral body and the transverse process at the LS-Sl junction (34). Bachop and Hilgendorf (35) found that the corporotransve rse liga ments were of rwo basic types: (1) broad and flat, and (2) rod like. The rodlike liga ments were usually to ugher (firmer ) than the flat type. Golub and Silverman (33) reported that these could calcify and be seen on radiographs. Bachop and Ro (36) fo und the gray communicating sympathetic ramus running through the opening above the corporotransverse liga ment. Bachop and Janse (34) believed that the corporotransverse liga ment could have a constricting effect on the anterior primary division (ventral ramus). That is, in patients with sciatica, as the leg is raised, the anterior primary division could be stretched across the liga ment, possibly mimicking the thigh and leg pain of a disc protrusion. Amonoo-Kuoffi et al. (37) have recentl y d iscussed accessory ligaments of the lYE They consistently found them throughout the lumbar regio n a nd mapped out the relationship of the spinal nerve, segmenta l veins and arteries, and the recurrent meningeal nerve through the openings between the ligaments. They concluded that the accessory liga ments tend to ho ld the above-mentioned structures in their proper place. Bakkum and Mesran (38) also found several ligaments at each level that decreased functional superior-

28 inferior diameter of the IVF by approximately one third .

Pain (Noclceptlon) of Spinal Origin The Perception of PaIn All pain should be considered as real and as having both physical and psychological components, one of which may predominate. Further, all pain alters the personality of the individual (39) . This personality usually terurns to the prepain state when the physical cause of the discomfort has sufficiently healed. In addition, pain is always subjective and is perceived by the patient in relation to experiences they have had with pain in their early years (40) .

Pain

the dorsal rOOt ganglia (DRG), which, with the exception of Cl and C2, are located within the intervertebral foramina of the spine. The sensory fibers that are associated with the recurrent meningeal nerve and the sympathetic nervous system provide a rOute for the transmission of pain arising from somatic structures of the anterior

aspect of the vertebral column. Fibers arising from these sources pass through the anterior primary division for a short distance before reaching the mixed spinal nerve. The Structures innervated by the ventral ramus, dorsal ramus, and recurrent meningeal nerve are listed in the boxes below.

>

Spine-Related Structures Innervated by the Ventral Ramus Possible Pain Generators

d. somadc Origin

Once a nociceptor has depolarized, it changes its properties, frequently becoming more sensitive to subsequent noxious stimu li. This increased 'sensi-

tivity to pain is known as hyperalgesia. The central nervous system also has several mechanisms

by which it, too, may create hyperalgesia in an area of injury. Therefore, after rissue is damaged it is usually more sensitive to pain until healing has occurred. After development of a pathologic condition or injury, hyperalgesia also may be present in the healthy tissues surrounding the site of the lesion. Frequently pain of spinal origin is the result of damage to severa l structures, and the effecrs of hyperalgesia allow for pain to be felt from tissues that, if injured to the same degree independently, may have gone unnoticed (41) . Most pain of spinal origin has a physical cause. One way to organize possible pain generators is by listing them according to the four main sources of neural innervation to spinal structures.

These sources are as follows: (1) the anterior primary division (ventral ramus), (2) the posterior primary division (dorsa l ramus), (3) the recurrent meningeal nerve, and (4) sensory fibers that course with the sympathetic nervous system (including fibers that run with the sympathetic trunk and also the gray communicating rami). All of these afferent nerves have their cell bodies in

• Referred pain from structures innervated by plexuses • Psoas muscle • Quadratus lumborum muscle • lntertransversarii muscles

>

Structures Innervated by the Dorsal Ramus Possible Pain Generators

• • • •

Deep back muscles Zygapophyseal joints Periosreum of posterior vertebral arch Interspinous, supraspinous, and intertransverse ligaments, ligamentum flavum

• Skin (upper cervical, middle cervical, and thoracic) lI............. 01 .... doni. n ........mtn:

• Erector spinae muscles • Splenius capitis and cervicis muscles (cervical

region) • Skin

2 Anatomy Ralated to Splnll SUbluXaUon

>

Structures Innervated by the Recurrent Meningeal Nerve Possible Pain Generators

29

Pain Generators Unique to the Cervical RegIon Pain generators unique to the cervical region include irritation of the nerves surrounding the

vertebra l artery and also pain arising from uncovertebral "joints" (joints between the uncinate

o Periosteum of posterior vertebral bodies o Internal vertebral (epidural) veins and basivertebral veins o Epidural adipose tissue • Posterior intervertebral disc o Posterior longitudinal ligament o Anterior spinal dura mater

Nerves Associated wtth the Sympathetic Nervous System Several structures are innervated by nerves that

arise from the sympathetic trunk and the gray communicating ram i. The sensory fibers of these nerves follow the gray rami to the anterior primary division, where rhey enrer the mixed spinal nerve and then reach rhe spina l cord by coursing through the dorsal roots. Pathology of the periosteum of the anterior and lateral vertebral body, which are innervated by sensory fibers traveling with gray rami, may lead to pain. Some of the most common causes of this type of pathologic condition

include

fracture,

neoplasm,

and

osteomyelitis (42). Sprain of the anterior longitudinal ligament or the outer layers of the anterior or larcral anulus also may resu lt in pain conducted by fibers that cou rse with the gray communicating rami. The structures innervated

by nerves

associated with the sympathetic trunk and gray communicating rami are listed in the box below.

>

Structures In nervated by Nerves Associated with the Sympathetic Trunk and the Gray Rami Communicantes Possible Pain Generators

processes and the vertebra l body immediately above). In addition, pain arising from pathology or dysfunction of the cervical Z-joints can refer to regions quite distant from the affected joint (43) . The two most common types of pain referral are (1) neck pain and head pain (headache) arising from the C2-C3 Z-joinrs, and (2) neck pain and shoulder pain arising from the C5-C6 Z-joints (44) . However, pain arising from almost any structure innervated by the upper four cervical nerves may refer to the head, resulting in head pains and headaches (43, 45-47). Pain originating from the region of the basiocciput and occipital condyles frequently refers to the orbital and frontal regions. Sweating, pallor, nausea, alterations of pulse, and other autonomic disturbances

have frequently been observed in association with disturb.ances of the suboccipital and upper cervical spine. The intensity of autonomic reactions seems

to be proportional to the stimulus, and the proximity of the stimulus to the suboccipital region. The autonomic responses range from mild subjective discomforts to measurable objective signs (45).

Pain Generators Unique to the Tboraclc Region Pain generators unique to the thoracic region

include pain arising from the costocorporea l and costotransverse anicuiarions. Compression frac-

ture of the vertebral bodies is also an important source of acute pain arising from the thoracic

region .

The Dorsal Root Ganglia and RalMcular Pain • Periosteum of the anterior and lateral vertebral bodies o Lateral intervertebral disc o Anterior intervertebral disc o Anterior longitudinal ligament

The dorsal root ganglia serve as modulators of spinal pain. They contain many neutopeptides associated with the transmission of pain (substance P, calcitonin gene-related peptide, vasoac-

tive intestinal peptide) (40). These substances may be released from the peripheral terminals of

30

Subluxallon

The ArtIcular Lesion

the sensory nerves that transmit pain, and the neuropeptides ma y reach these peripheral terminals (receptors) by axona l transport mechan isms. The presence of neurope ptides in and around the receptors may "prime" them by maki ng them more susceptible to depolarization (40). Direcr pressure or irritation of the dorsal roots or dorsal

root ganglia results in radicular pain. Radicu1ar pain is sharp and stabbing in nature and radia res a long a narrow band, and is accom panied by other sensory or mOlOr deficits. Some of the ca uses of radicular pain include intervertebral disc protrusio n, spinal (vertebral) cana l stenosis, and other space-occupyi ng lesions.

>

Radicular Pain

• Pain arising from the dorsal root or the

dorsal rool ganglion. Usually causes pain to be referred along a portion of the course of the nerve or nerves formed from the affected dorsal root. • This is known as a dermatornat pattern.

Somatic Referred Pain There a re several possible mechanisms of pain referral from a somatic structure. Perhaps one of

the m OSt importa nt is attributable to the internal organ ization of the spinal cord . The nociceptive

to the postcentral gy rus of the cerebra l cortex. The back and neck have ve ry small regions allotted 10 them on the postcentral gyr us (sensory homu nculus), a nd this also may contribute to the poor loca lization of spinal pain. In addition, the tract neurons for ascending pain pathways most frequently ca rry nociceptive information from cutaneous areas. Therefore, when the tract neurons are sti mulated to nre, the cerebral cortex (where conscious awareness of pain occurs) may interpret the impu lse as coming from a cutaneous region or from another, morc recently injured, region. Either of these areas may be distant to the structure that is currently damaged or inflamed. This phenomenon is sometimes referred to as "pain memory" (48,49) . Somatic referred pain is characterized as being a dull achi ng pain that is difficulr to localize a nd rather conStant in nature. Activity of the muscles and the Z-joints, as well as spinal manipularion of the Z-joints, tends to decrease pain through a "gate contro l" type of mechanism (39). Therefo re, if pain is of somatic origi n, the patient may benefit mOSt by treatment that promotes ac tivity and movement (39). Of course, ca re must be taken not to comp romise the da maged tissue in any way (see box) .

>

Distinguishing Features of Somatic Referred Pain

informa ti on coming in from a pain generator is

dispersed by ascending or descending with in the tract of Lissauer for several cord segments before synapsing on tract neurons of several cord levels.

Therefore, nociceptive information entering from several vertebral levels may converge in the sa me interneuronal pool. The dispersal of incoming afferents onto different tract neurons, in combination with the convergence of several different afferents onto single-tract neurons, may decrease the ability of the central nervous system to loca lize pain. This type of dispersal a nd convergence also may be found at the second synapse along the pain pathway, which is in the ve ntra l posterior lateral nucleus of the thalamus. Finally the vent ral posterior latera l thalamic nucleus projects

• Dull ache • Difficult to localize • Rather constant in nature

Central Transmission of Pain The afferent fibers that cOllvey nociception a re group A-delta and gro up C fibers. These fibers enter the dorsolateral tract of Lissauer located at rh e tip of the dorsal horn . Within this region, collateral branches of those fibers rhat continue directl y into [he gray marrer ascend or descend numerous cord segment levels before they, too, enter the dorsal horn. The A-delta fibe rs, which

31 convey pain quickly and rapidly, terminate in lamina I and laminas rv through VI. The group C fibers, which convey a dull sensation of pain at a slow ratc, terminate in lamina II. The neurons, which transmit the information to higher centers, are located in various laminae of the gray marrero Surgical cordotOmy procedures that relieve pain have shown that the major fibers that transmit nociceprion to higher centers decussate in the ventral white commissure and then ascend in the

anterolateral quadrant of the white matter of the spinal cord (50). Alternative pathways also may be involved, although their course and function in humans remains unclear.

The Neasplnothalamic Tract One of the tracts in the anterolateral quadrant is the neospinothalamic tract (Figure 2-6). This rract ascends through the brainstem to the ventral lateral nucleus (posterior part) and also to the posterior nucleus of the thalamus with little or no input to the brainstem. From the thalamus, axons course

[0

the somesrheric region of the correx,

that is, the postcentral gyrus and the posterior part of the paracentral lobu le of the parietal lobe. As the axons ascend, body parts are represented in specific regions of the tract, and in the cerebral cortex a parrern is retained such that a specific area of cortex corresponds to the region of the body from which the sensory fibers originate.

-.!~

The primary pathway for transmittal of nociceprion-the neospinorhalamic tract. (Illustration by Dina Juarez. The National College of Chiropractic.)

This cortical representation is referred to as the

sensory homunculus. The size of the body part represented on the homunculus reflects the amount of sensory innervation devoted to that

body area. As previously mentioned, this unequa l neuronal representation may explain why localization of sensations, such as pain, is morc difficult in one region (such as the back) than in another. The neospinorhalamic tract synapses in

the region of the sensory homunculus and provides the basis for the discriminatory qua lities of pain sensation, such as stimulus intensity and spatial localization.

lateral quadrant are the paleospinothalamic and spinoreticular tractS (Figure 2-7). The paleospinothalamic tract, which ascends through the brainstem and likely contributes collateral branches to the reticular formation, terminates in

the midline and intralaminar tha lamic nuclei. From these nuciei, thalamic fibers travel to regions associated with the limbic system and to widespread areas of cerebra l cortex such as the orbitofrontal region. The spinoreticular tract ascends

[0

the reticu-

The PaIeospinothalamlc and SpInoreticulll' Tracts

lar formation of the brainstem. The reticular for· mation is a complex network of neurons located throughout the core of the brainstem. It has

Two additional tracts that ascend in the anrero-

numerous functions and is a major component,

32

SUl*lXatIon TIle ArtIcular Lellon is that they both terminate in the same region of the thalamus, which in turn projects to nonspecific areas of cerebral cortex. Another similarity is that neither of them is somatotopically organized. Both the spinoreticular and paleospinothalamic tracts may be involved with the generation of chronic pain and the qualities associated with that sensation . The response of the brain to painful stimuli is quite involved. The perception of pain takes place in the thalamus, postcentral gyrus, frontal cortex (affective component), and temporal cortex (memoty of previous pain component) (39). The unpleasant emotional response associated with pain, however, seems to be associ-

ated with the limbic system. The limbic system allows one to perceive a sensation as being

uncomfortable, aching, or hurting (41 ). The focusing of one's attention on the painful area is likely a function of the ascending reticular activating system.

SUpraspinal Control

FIgIre 2:·7 The paleospinothalamic tract and the spinoreticular tract. (illustration by Dino Juarez. The National College of Chiropractic.)

Evidence from studies in which electrical stimu lation of regions of the brainstem produced analgesia (51) indicates that there are descending pathways that can modulate nociceptive signals. One of the components of this endogenous pain control system is the periaqueductal gray matter (PAG) of the midbrain. This region has a major projection to the nucleus raphe magnus, which is located in the midline of the rostroventral medulla. This nucleus is rich in the neurotransmitter serotonin. From [his region, serotonergic

along with the thalamus and the cerebral cortex, of the ascending reticular activating system . The ascending reticular activating system provides the

circuitry rhrough which arousal and attentiveness are maintained. The tract neurons synapsing in th e reticular formation form complex connections

within this region and subsequently project to brainstem nuclei, the hypothalamus, and the midline and intralaminar nucleus of the thalamus. Subsequent thalamic projections course to widespread areas of cerebral cortex. The paleospinothalamic and spinoreticu lar tracts possess sim ilar characteristics. One of these

fibers course into the dorsolateral funiculus of the spinal cord (raphe-spi na l tract) and synapse heavily on neurons in the superficial dorsal horn (laminae I and U) . The superficial dorsal horn is a lso the region that receives input from afferent fibers conveying nociception . In addition, it is the location of the origin of the spinothalamic tracts (51, 52) and is the area involved with the segmental modu lation of nociception (see previous discus-

sion). Descending fibers synapse on neurons, which include enkephalin (an opioid peptide), containing inhibitory interneurons and also on the nociceptive projection neurons (tract neu-

33 rons). The opioid-containing inhibirory interneurons arc in close proximity to both primary nociceptive afferents and the tran neurons. In fact, the afferent endings and the dendrites of the tract neurons both contain opioid receprors (55). Pharmacologic studies have shown that the release of opioid peptides from the inhibitory interneurons block transmission of nociception by two mechanisms. One mechanism is by binding ro receprors and blocking the release of neurotransmitters, such as subsrance P, from the primary afferent fibers . Although direct axoaxonic synapses between enkephalin neurons and the primary afferent fibers have not yet been found, enkephalins may possibly bind ro receptors by diffusing from their site of release to the presynaptic membrane of the afferent fiber (52-54). The second mechanism by which inhibitory inrerneurons can mediate spinal neurotransmission of nociception is by directly synapsing with the postsynaptic membrane of the tract neuron. This occurrence has been well documented (5254). Through these connections, nociceptive transmission is prevented. As mentioned previously, analgesia can be produced by neural stimulation. Analgesia can be produced also by the administration of opiates into the central nervous system. The areas that are activated by the opiates are the same as those

that produce analgesia when electrically stimulated, that is, the PAG and the rostroventral medulla. This lends credence ro the theory that endogenous opioid peptides, which have been found in the brain, can activate the descending system (52). In addition to the seroronergic descending pathway, there are other fibers descending from the pons (50, 53) that appear to be involved with control of the nociceptive system. These descending fibers camain norepinephrine and appear to

inhibit nociception at the dorsal horn level. At the same time, however, collateral branches of these fibers synapse on the seroronergic neurons of the raphe nuclei. The subsequent release of norepinephrine at this level results in "tonic inhibition" of the raphe-spinal neurons (53). Thus both sys-

terns provide a descending component ro the mechanism for controlling pain. Feeding into these systems is the nociceptive information transmitted through ascending pathways (41), possibly the spinomesencephalic tract and input from the reticular formation, and possibly Stressinduced input channeled through the limbic system and hypothalamus (52) .

Acknowledgments The authors thank Mr. James McKay, Ms. Sheila Meadows, and Dr. Michael Kiely for invaluable assistance during the preparation of this chapter.

References 1. Giles LG. The surface lamina of the articular cartilage of human zygapophyseal joinrs. Anat Roc t 992;

233,350-356. 2. Paris S. AnalOrny as related (0 function and pain. Orthopedic clinics of Norch America 1983; 14:475-489. 3. Giles LG, Taylor JR. Human zygapophyseal joint capsule and synovial fold innervarion. Sr J Rhcumarol 1987;

26,93-8. 4. Xu G, ct al.: Normal variations of the lumbar facet loint capsules. Clin Anat 1991; 4: 1 17-22. 5. Williams PL, et al.: Grays' anatomy. 37th ed., New York: Churchill Livingstone, 1989. 6. Jeffries B. Facet joint injections. Spine: State of the Art Reviews 1988; 2:409-17. 7. Engle R, Bogduk N. The menisci of the lumbar zygapophysia1loints. J Anat 1982; 135:795-809. 8. Panjabi M, Oxland T, Parks E. Quanmative anatomy of cervical spine ligamenrs. Part II. Middle and lower ccrvical spine. J Spinal Dis 1991; 4:277-85. 9. Oliver J, Middledltch A. Functional anatomy of the spine. Oxford: Bunerworth Heinemann, 1991. 10. Yu S, Sether L, Haughton VM. Facet jOint menisci of the cervical spine: Correlative MR imaging and cryomicrotomy study. Radiology 1987; 164:79-82. II. Wyke B. The neurology of low back pain. In: Jayson M. The lumbar spine and back pain. 3rd ed. New York: Churchill Livingstone, 1987. 12. Buckwalter, et al. Articular cartilage and intervertebral disc proteoglycans differ in structure: An electron microSCOpiC study. J Orthop Res 1989; 7: 146-51. 13. Mendel, et al. Neural e1emenrs in human cervical intervertebral diSCS. Spine 1992; 17: 132-5. 14. Bogduk N, Twomey LT. Clinical anatomy of the lumbar spine. London: Churchill Livingstone, 1991. 15. Humzah MD, Soames RW. Human intervertebral disc: Structure and function. Anar Rec 1988; 220:337-56.

34 16. Ito S, er al. An o bservation of ruptured annulus fibrosus in lumbar discs. J Spinal Dis 1991 ; 4:462-6. 17. Kraemer J. et at. Water and electrolyte coment o f human intervertebral di scs under variable load. Spine 1985; 0,69-71. 18. leBlanc, er al. The spine: C hanges in T2 relaxation times from disuse. Radiology 1988; 169: I 05-7. 19. Coventry MS. Anato my o f the intervertebral d isc. Clin Orthop 1969; 67 ,9- 15. 20. Bayliss, et al. Proreoglycan synthesis in the human imervertebral disc: Variation with age, region and pathology. Spine 1988; 13,972-8 1. 21. Ba hk YW, Lee JM. Measure-set computed tomographic analysis of inferna l architectures of lumbar disc: Clinical and histologic srud ies. Invest Radiol 1988; 23: 17-23. 22. Mix ter WJ. Barr j5. Rupture of the intervertebral disc w ith involvement of the spina l cana l. N Eng J Med 1934; 211,210-15. 23. Martin G. The role o f trauma in disc protrusion, N Z Med J 1978; M . "h, 208-211. 24. Sanders M, Stein K. Conservati ve management of herniated nucleus pulposes: treatment approaches. J Ma nipula tive Physiol Ther 1988; 11 :309-13. 25. Alcalay M , et al. Traitement par nuclcolyse ala chymopapaine des hernies discales a forme purement lomba lgique. Revue du Rhumatisme 1988; 55:741-5. 26. Dabezies, et al. Safety a nd efficacy of chymo papain (disease) in the treatment of sciatica due to a herniated nucleus pulposus: results of a double-blind study. Spine 1988; 13,561-5. 27. Bogduk N. Cli nica l a natomy of the lumbar spine. London : C hurchill Livingsto ne, 199 1. 28. Bogd uk N, Tynan W, Wil son A. The nerve supply to the human lumbar intervertebral discs. J Anat 198 1; 132,39-56. 29. Bland J. The cervica l spine: from a natomy to clinical care. Medical Times 1989; 11 7:15-33. 30. Czervionke L, er al. Cervical neu ral fora mina: Correlative analOmic and MR imaging study. Radiology 1988; 169,753-9. 3 t. Hewi tt W. The intervertebral foram en. Physiotherapy 1970; 56,332-6. 32. Pfaundler S. Pedicle origin and intervertebral compartment in the lumbar and upper sacral spine. Acta Neurochir 1989; 97, 158-65. 33. Golub B, Siverman B. Transforaminalligaments of the lumbar spine. J Bone Joint Surg 1969; 51 :947-56. 34. Bacho p W, Janse J. The corporotransverse ligament at the L5 intervertebral foramen (Abstract). Anar Rec 1983; 205. 35. Sachop W, a nd H ilgendo rf C. Transforaminalligamcnrs of the human lumbar spine (Abstract). Anar Rec 198 1; 199.

36. Bachop WE, Ro CS. A ligament sepa rating rhe nerve from the blood vessels at the L5 intervertebral foramen. J Bone Joint Surg 1984; 8:437. 37. Amo noo-Kuofi HS, er al. Ligaments associated with lumbar intervertebra l foramina. 1. LI to L4. J Anar 1988; 156, 177-83. 38. Bakkum BW, Mesra n M . The effects of transformatio na l ligaments on the sizes o fTI I to L5 human intervertebra l foramina.J Manipulative Physiol Ther 1994; 17(8): (in press). 39. Kirkaldy-Willis WHo The mediation of pain. In : Kirkald)'Willis W, ed. Managing low back pain. 2nd ed. New Yo rk : C hurchill Li vingstone, 1988. 40. Weinstein WHo The perception o f pa in. In : KirkaldyWillis W, cd. Managing low back pa in. 2nd ed. New Yo rk: Churchill Livingstone, 1988. 41. Haldeman S. The neurophysiology of spinal pain. In : H a ldeman S, ed. Principles and practice of chiropractic. 2nd ed. Eas[ Norwa lk, Connecticut: Appleton a nd Lange, 1992. 42. Bogduk N. The innervation of the lumbar spine. Spine 1983; 8,286-93. 43. Dwyer A, Aprill C, Bogduk N. Ce rvica l zygapophyseal joint pain pancrns. I. A stud y in normal volu nteers, Spi ne 1990; 15,453-7. 44 . Bogduk N, Marsland A. The cervical zygapophysea l joints as a source of neck pain. Spine 1988; 13:6 10-17. 45. Campbell, Parsons. J Nerv Menta l Dis 1944; 99:544-5 1. 46. Bogduk N, Engel R. The menisci of the lumbar zygapophysea l joints. Spine 1984; 9:45~0. 47. Aprill C, Dwyer A, Bogduk N. Ce rvica l zygapophysea l joint pa in panerns. 1I. A clinical evalu ation . Spine 1990; 15(6),458-6 1. 48 . Carpenter MB, Suti n J . H uma n neuroanatomy. 8th ed. Ba ltimore: Williams & Wilkins, 1983. 49. Nolte J . The human brain. 2nd cd. Sr. Lo uis: Mosby, 1988. 50. Hofferr MJ. The neurophysiology of pain. Neurol Clin J 989; 7(2), 183-203. 5 1. Basba um AI, Fields Hi. Endogenous pain control mechanisms: review and hypothesis. Ann Neurol 1978; 4,451 -62. 52. Jessell TM, Kelly DD. !'ain and a nalgesia . In : Kandel ER, Schwartz JH, Jessell TM, eds. Principles of neu ral science. 3 rd ed. New York: Elsevier; 1991. 53. Basbaum AI. Cytochemica l S{udics of the neural circuitry underlying pain and pain conrro l. Acta Neurochir 1987; 38 (,uppl),5-lS. 5 4. Besson JM . The physiological basis of pain pathways and the segmemal controls of pain. Acta Anaesth Belg 1988; 39 (,uppl 2),47-51.

Basic Scientific Evidence for Chiropractic Subluxation Howard Vernon

Key words

Subluxation, animal model, basic science, neuroscience

After reading this chapter you should be able to answer the following questions:

QuesUoo #1

Has chiropractic's subluxation theory been explored by basic science research within the profession?

QuesUon #2

Has it been verified by studies using animal models?

QuesUon #3

Have the predicted aspects of subluxation theory been verified?

36

C

hiropractors have traditionally viewed spinal subluxation from twO points of view. First, it has been regarded as the set of symptoms experienced by the patient, typically consisting of pain, both local to the spine and referred to distal sites, stiffness, and, less frequently, sensory disturbances. Recently, this aspect of subluxation has been termed the subluxation syndrome (1,2). Secondly, it has been regarded as a pathophysiologic disorder of the motion segment of the spine, complete with various categories of tissue damage and functional disturbances. This aspect has recently been described as the sllbluxation complex (3-5) . It is logical to view the latter, the actual disorder (the "complex"), as causative of, or at least strongly associated with, the former. This fulfils the mechanistic demand in medical nosology that all clinical symptoms must arise from some disturbance of biologic function (as opposed to being psychogenic in origin). Although this logic has been implicitly accepted by chiropractors and others with similar viewpoints, it has met with opposition in orthodox circles. In addition as a scientific hypothesis ("the disorder causes the symptoms") it has received negligible attention by chiropractic researchers, in some part because of the inherent difficulties in conducting studies to test it, a point that will be elaborated on further. Opposition from orthodoxy arises in no small measure from the fact that the empirical data available to support the premise are so scanty. In addition, in the medical model, the same set of symptomatology just described has been attributed to quite different explanations, none of them requiring the characteristics of the chiropractor's subluxation. Curiously, one of the most prevalent medical explanations for much of this sort of symptomatology (wh ich, by the way, is among the most prevalent in general medicine [6]), is that the cause is unknown, giving rise to the term idio-

pathic back pain.

Many chiropractors, however, might take issue with the premise that there is very little substantive evidence that the subluxation complex actually exists or is the causative agent of much of the subluxation syndrome. Until recently, they might have argued that the vaSt cumulative experience of the many practitioners, especially those who took the time to publish, some in reputable journals, was prima faciae evidence that when the subluxation is adjusted, the symptoms resolve, and therefore they must have been attributable to subluxation beforehand. More recently, the profession might argue that the many well-conducted clinical trials of manipulation for back and neck pain " prove the point" (7). Unfortunately, both arguments 3rc based on retrospective interpretation of clinical events. Year (8) and others have quite correctly termed this the fallacy of "post hoc ergo propter hoc" (after the fact, therefore because of it). There may be many other valid and rival explanations for the clinical improvements in patients who have their spines manipu-

lated by a chiropractor. Substantiating a pathophysiologic theory with clinical evidence is risky business, especially in the absence of any prospectively obtained evidence from basic scientific studies. In fact, no study exists in which subluxation of the spine has been operationally defined (fo r example, as a misalignment of two spinous processes of 3 mm or more) and then induced in a human patient. It is doubtful that such a study could ever pass an Institutional Review Board in the first place. There is a small body of work in which one of the aspects of the theoretical model-in this case, painful irritation of the deep articular and muscular tissues-has been induced in humans (by injections of hypertonic saline into the facet joints, sacroiliac joints, and the deep suboccipital muscles). These studies (9- 11 ) provide what is known in experimental science as a

model of the theory. In these studies, the prediction from the model-that a painful disorder of the posterior motion segment tissues would provoke diffuse

3 BasIc ScIentIIIc Evidence lor CfIIroprICllc SlII*Ixatlon patterns of spinal pain that often would be referred to dista l ateas of the body-has been verified. This qualifies as the sort of prospectively obtained data that wou ld be necessary to substantiate the more generic theory described above. Given the ethical limitations of conducting

37

Model linkage: the hard way

subluxation research on normal humans, and

given the logical difficulties in interpreting da ta from clinica l stud ies, basic scientific studies employing anima l models offer an attractive alternative for chiropractic researchers and prac-

titioners alike. This chapter reviews anima l model studies that have been conducted to investigate the subluxation complex. The process of modeling in basic scientific research achieves a representation of the part of the empirical world undet investigation. De Bono defines a model as "a method of transferring some relarionship or process from its actua l setting to a setting where it is more conveniently

studied" (12) . The box below lists some of the advantages of using a nimal models in the study of

>

Animal Model Studies: Reasons for T heir Use

• • • • • •

• •

Test theories derived from conceptual models Provide data to support clinical experience High level of experimental control Prospecrive; therefore can explore cause and effect relationships Explore "treatment" effects when lesion is reversed Explore physiologic components of subluxation, but cannot explore behavioral components in acute experiments Chronic experiments may allow for exploration of behavioral effects Animallrudies are the "Holy Grail" of clinical science

spinal subluxation. There are essentially two approaches that can be (and have been) adopted to create a suitable

Rt111'13-1

Flow chart of animal modeling of the

su bluxarion-the hard way.

model of spinal subluxation. The first of these is depicted in Figure 3-1 and shows a process whereby the primary objecti ve of the exercise is to create the essential component of the human version of the problem, namely, vertebra l misalign ment. In this approach, the investigators

38 devote considerable time [Q devising innovarive methods of creating the kind of misalignment that is thought to exist in the human condition . After doing so, the effects of this modeled condition in whatever animal preparation has been selected then can be observed . This approach retains the highest fidelity to the natural circumstances and achieves the highest level of prospective validity, because, as was mentioned previously, the disorder was created first and its putative effects were studied thereafter. Unfortunately, as we will see latet, this approach is by far the more difficult, and possibly even less valid than is necessary. First, creating the minor degree of misalignment necessary to model the chiropractic version of a subluxation in an animal spine is surprisingly difficult, and many innovative attempts have been made to do just that. Second, after creating such a misalignment, it is necessary to actually verify its presence; that is, it must be determined how much force was used to effect the misalignment, and by how many millimeters or degrees the test vertebra is misaligned compared with its neighbors. These measurements are not easily performed and lack a critical level of reliability. Fina ll y, the conceptual model of subluxation posits that the vertebral misalignment causes some form of "nerve interference. " This has come to be understood as either (1) some element of compression of the spinal nerves in the environs of the intervertebral foramen or (2) the initiation of pain in the spinal joints that is capable of creating secondary aberrant reflex effects such as

requirements, and it will be shown that it has never been achieved in total in any of the reported studies. This prompts us to consider an alternative approach, which is depicted in Figure 3-2. It is much easier, both experimentally and logically, ro start by accepting the premise that the misalignment creates the nerve interference and to begin the experiment at that point, that is, by modeling the effects of either the nerve root compression or the spinal joint pain . Studies employing this approach have been far more productive than those employing the first approach. When sufficient data have been gathered from studies like this, then investigators can return to the problem of whether the misalignment really produces the proximate effects.

Review 01 Studies The following section consists of a structured review of published works, in chronological order, in which an animal model was employed to investigate some aspect of the behavior or nature of the spinal subluxation. With one exception, the first of these srudies, these studies appear in the chiropractic literature.

Study #1 No review of this body of work could begin without first examining the work of Louisa Burns and her osteopathic colleagues, which took place

increases in motoneuron or sympathetic neural

activity. In the misalignment approach to animal modeling, it is necessary for investigators to provide evidence that the misalignment has caused either of these two forms of nerve interference. In other words, nerve rOOt compression and joint pain become the proximate or first-order effects of the experimental misalignment. They must be adequately demonstrated before the distal or second-order effects, such as disturbances in reflexes or in nerve conduction, can be demonstrated and logically correlated with the misalignment. This is a difficult and unwieldy sequence of experimental

Model linkage; the eosy way

FIgII'e 3-2 Flow chart of anImal modeling-the easy way.

3 Balle ScIenIIIIc Ev1denc:8 , ... Chlrapracllc SUbluXation from 1917 ro 1948 at the A.T. Sti ll Reseatch Institute's Sunny Slope Laborarory in Chicago, Illinois.

TITlf: Pathogenesis of visceral disease following

39

loss of elasticity, increased contract ions, and

increased fa tiguability. As with the othet tissues, in the ea rl y stages, there was edema in the muscles, whe reas in the larer stages of the lesion, fibriotic changes and atrop hy were observed.

vertebral lesions

Nerve Uu.: In the early stages, spina l cord hype r-

AUTlIORS: Burns L, Chand ler, Rice, et al.

AfoWUJ.S USBI: Rabbit, gui nea pig, cat, dog, goat SUBlUXATION COMPOI'oINT MOOB.BI: "... A slight slipping or maladjustment of the articular surfaces"

METIIOOS: 1) Manual misal ignments 2) Misalignments confirmed by manua l palpation, radiographic evidence, and autopsy

3) Control lesions produced by deep pressure or other stimulations (for example, electrica l,

chemical, thermal, or mechanical) 4) Histologic exami nations were used in both the spina l area and the viscera. Morphologic

em ia was nored. In [he long-term experiments,

primary degeneration of the nerve fibers at the site of the lesion was observed as well as ch romarolysis of the spina l neurons. Burns et al. noted that Wallerian degeneration rarely occurred. ArtICIDr 1InuaI: Edema and changes in the synovia l fluid of the lesioned articular su rfaces were noted in the earl y stages. Later, reductions in the synovial fluid and increases in its viscosity were

noted, culminati ng in fib rotic changes. In the late r stages, "join[ mice" were observed and were

thought to be the product of fibrotic degeneration around the joint capsule, which itself was found ro be thickened and less elastic. The reporting of "joint mice" may be the fi rst mention of w hat has

come ro be known as joint meniscoids (13) .

examinations were also used.

5 ) Experiments were both short-term and longterm.

lntIrvertllllrll dIIc tIIIUe: Again, in the earl y stages, increased internal pressure within the disc as well

as loss of elasticity of the disc were noted. In the

FNRS: The findings of these experiments a re

later stages, fluid resorption, fibrotic invasion,

provided by Burns et al. in summary sections according to the different tissue types. These are repeated here:

and atrop hy of the disc cells we re noted. Burns et a l. proposed the following mechanism to explain how the minor misalignment of the intervertebral joint could have such profound effects on the

SlIm: In the early tages after misalignment, hyperemia was observed in the skin near the lesion. In the chronic stages, thickening and fibrotic changes were always noted.

intervertebral disc: the misalignment resulred in

asymmetry of pressure and reduced mobi li ry. As the posterior vertebralligamenrs thickened, compression of the surrounding circulatory vessels resulred, impairing loca l circu larion ro and from

PeItI: In the ch ron ic stages, desquamation and thinning of the fur was noted around the lesion.

the cancellous bone and resulting in loss of nutrition to the disc. Thus, both mechanical and metaboli c impairment occurred ro the tissues of the

SID:utaneouIIInuaI: As with the skin, in the early stages of the lesion, edema was always noted. Latet, fibrotic thickening was observed.

disc.

Deep 1!1i1a1111UIdeI: The following findings wete

ety of viscera were ana lyzed morphologically and histologically. The latter two thirds of Burns et

VllceralIInuaI: Usi ng short-term and long-term prepararions, postmortem findings in a grear va ri-

frequently noted once the lesion had settled in:

40

SUbluXation

The ArlIN.. lBIIon

al.'s text is devoted to a system-by-system presentation of the various results. For the purposes of this chapter, the featu res common to a l1 the viscera are noted. These findings were always reported to impair the function of the particular organ involved. In the ea rl y stages of the lesion, the viscera always demonstrated impairments of circulation, changes in smooth muscle function, and changes in secretory function of the various glands involved. In the later stages, circulatory congestion and edema were always observed, as well as denervation-related changes and diminished elasticity of the surrounding connective tissues. Burns et al. summarized their findings in the fol1owing generic mechanism, which was thought to result from the induction of the minor subluxationlike lesion: the lesion produced segmental1y organized somata-a utonomic reflex dysfunction, resulting first in disturbed regulation of the viscera. This was fol1owed developmental1y by disturbances of function and ultimately by protopathologic changes. [n many instances, actual pathologic changes were observed, such as the development of ulcerous lesions in the gastric mucosa and infarcts in the kidney tissue. This body of work is seminal in the history of basic scientific investigations of spinal subluxation (14-16). It was a vast and expansive body of work while at the same time being precise, methodical, fastidious, and focused. It is remarkable that, in the laner part of this century, modern investigators have not even come close to replicating the breadth of findings in these investigations. Unfortunately, that is the on ly downfal1 of the work left to us by Louisa Burns and her col1eagues. As time has passed, experimental techniques have adva nced so much that these studies have become outdated, a nd their findings are cal1ed into q uestion. It is hoped that current and future investigators in chiropractic and osteopathy can conduct the kind of modern investigations that will vindicate the enormous historic contribution made by the scientists at the Sunny Slope Laboratory.

Study #2 mu:

Researching the subluxation on the domestic rabbit

AUTHOII: Carl Cleveland, Jr., and col1eagues JOUIINAl.S: 1) Cleveland Col1ege of Chiropractic Monograph 1961 2) Science Rev Chir 1965; J (4):5-28 .

Al'AtU: Rabbit

S\JIII.UXATlON CIM'IIMNT MOO8BJ: Misalignment of the intervertebra l joint

PIIT1IOIIS: 1) Minimal surgical procedure using external metal splint attached to spinous processes of three vertebrae. Subluxation produced by tightening a screw on the frame of the splint, thereby lateral1y misaligning the middle vertebra

2) Degree of misalignment variable and easily rep licable 3) Procedure done under fluoroscopic assistance 4) Misalignment was verified by radiographs 5) Outcomes were physiologic measures such as heart rate, blood pressure, erc. 6) Pathologic and postmortem ana lyses conducted o n various tissues 7) Short-term and long-term experiments proposed; no controls reported

FHRS: Two case studies were reported of a successful induction of a T12 subluxation. In both cases, subsequent kidney abnorma lities were described. Mention is made of numerous other experiments in which "hearr diseases, valvular leakages, paralysis, arrhythmias, vasomotor paralysis, dropsy, kidney conditions, and the formation of tumours" were observed.

41

8 Balle Sc:Ien1IIIc Evld8nc8 IIII' Chiropractic BWluxatlon This study represents the first attempt by chiropractic investigators to employ an animal

model of spinal subluxation. The method used was quite innovative and relatively noninvasive. Unfortunately, no future investigators carried this method forward. This may have been because of rhe very limited dissemination of the Cleveland report.

quem years, orrhodox scientists came to reconsider their opposition to the notion of nerve pres-

sure, as witnessed by the work of Sunderland (1 7) , Rydevik et al. (18 ), and others. In this article, Haldeman reports on several features of compression-related nerve dysfunction . The first observation was the reduction of conduction ve locity associated with the constric-

Study #3 TTTlf: Changes in the structure and function of the sciatic nerve caused by constriction

tion ex periment. Secondly, Haldeman reported on blockage ofaxoplasmic flow along the nerve trunk, evidenced on histologic examination by

swelling of the nerve proximal to rhe consrriction site. These findings lent great support to the preva iling

notions

among

chiropractic

thinkers

regarding the importance of subluxogenic nerve

AUllIOII: Haldeman S (with Drum D)

compression.

JOUIINALS: 1) M.Sc. Thesis, 1969. 2) J Clin Chiro, 1969. ~ Frog

Study #4 TTTlf: Experimental induction of vertebra l subluxation in laboratory anima ls

SIIIluxmoN COM'OMI'IT MOOBBI: Subluxogenic compression of nerve root

AIITIIORS: Lin HL, Fujii A, Rebech ini-Zasadny H, Hartz DL

WTIIOIIS:

J Manipulative Physiol Ther 1978;

1) Surgical procedure/short-term experiment 2) Ligation of sciatic nerve 3) e1ectrophysiologic and histologic analysis of sciatic nerve Structures

JOIIINAl:

fRRS: This study represents the first attempt

SIIIlUXOGIMC COM'OMI'IT MOOBBI:

to use an animal experiment to model the purported compression-related effects of subluxation on nerve function. Traditional chiropractic theory placed a great deal of emphasis on the notion of subluxation creating interference on nerve function by creating direct bony pressure in the intervertebral foramen; this was the so-called " bone out of place/garden hose" theory. This idea was the object of much scorn in orthodox circles, and this study by Haldeman did much to counter this by showing the deleterious effects of even mild

1) Vertebral misalignment 2) Intervertebral fixation

levels of compression on a major nerve. In subse-

1:63-68. ~ Rat

.ntOIIS: 1) Surgica l procedure/se mi-short-term experiment

2) Misalignment and fixation produced by implantation of screws into rhe spinous processes of TID and Til 3) Screws joined and tightened by variable springs 4 ) Radiographic verification of alignment

42 5) Semichronic experiment lasting 14 days 6) Shams and controls used

FNIWGS: This experiment, co some degree, did follow up on rhe work of Cleveland and his colleagues by using an externa ll y implanted device co successfully create spinal misalignment. In this study, the on ly direction of misalignment was downwa rd, that is, the spinous processes were approximated, creating a backward extension of the intervertebral joint. Radiographic evidence (see Figure 3-3) showed that an average of 7 ~ 3 degrees of extension was induced. This was compared with no evident extension in the shams and the controls. This a rticle is certainly one of the strongest in its use of sham and control preparations and in its use of radiographic studies as an

~

objective outcome. Unfortunately, this group of investigacors did not report on any subsequent effects of the induced misalignment, nor did they publish any further work. It seems that this model was lost to future investigators.

Study #5 mu:

The present use of guinea pigs for chiropractic research

AI/11IORS: MacGregor M, Wiles M, Grice A JOUIINAl.: Canadian Chiro Assoc 1980; 24 (3):101-7.

8-8 Surgically induced misalignment of T10 and Til. (From Lin er 31. 1979.)

3 Basic Sclentllic Evidence lor Chiropractic Subluxation ANNAL: Guinea pig

43

nal area by implantation of loose Silastic ligatures surrounding the nerve

SUBLUXOGENIC COMPONENT MOOEUD: Misalignment FlllllNGS: This study established, for the first time, a workable and valid model of the kind of

METHODS: 1) Nonsurgica l procedure 2) External concussion over spinous processes, using a mechanical "adjusting" device

nerve compression and irritation that, as a pro-

posed mechanism, dominated the chiropractic paradigm. It is interesting to note that this model of chronic sciatic constriction predates by 8 years

IRInGS: This srudy was a reporr of preliminary findings of a proposed experiment to use a mechanical Uadjusting" device to concuss the

the model of neuropathic pain devised by prominent pain researchers at the National Institutes of Health (NIH) (19).

spinous process of a tcst vertebra into misalign-

ment. This study artempted to determine the feasibility of using this model by assessing normal animal parameters over an extended period and

by determining the reliability of palpation of the animal's spine for detection of the misalignment.

Unfortunately, no induction of the model was done, and no further reporrs were issued by this group. The use of an external concussion device

was explored in later papers, particularly by the group headed by Ken DeBoer.

Triano and Luttges reported a number of critical observations that are consistent with the chiropractic theory of subluxogenic nerve compression, including (1) inflammation demonstrated in the ep ineurium surrounding the Si lastic imp lantation; (2) diminished nerve conduction velocities, despite there being no complete circumferential constriction of the nerve; (3) faci litation effects noted in nerve refractory recovery rimes; and (4)

motor d isturbances observed as disturbances in gait as a result of dysfunction of the affected (that is, surgically treated) hind limb.

Study #8

Study #7

TITLE:

Subtle intermittent mechanical irritation of the sciatic nerves of mice

TITU: An attempt to induce vertebral lesions in rabbits by mechanica l irritation

AUTHORS: Triano J, Luttges M AUTHOR: DeBoer K JOURNAL: J Manipulative Physiol Ther 1980; 3 (2):75-80.

JOURNAL: J Manipulative Physiol Ther 1981; 4 (3):119-27.

ANI't'IAL: Mouse ANIMAL: Rabb it

SUBLUXATION COMPOM3VT MODRED: Subluxogenic nerve rOOt compression

SUBLUXOGENIC COMPOMNT MODRED: Misal ignment

METHODS:

METHODS:

1) Surgical procedure 2) Short-term and long-term experiments 3) Controls used

1) Nonsurgica l procedure in awake anima ls 2) Lesions (misa lignments) induced by means of an external concussive adjusting device (Figure

4) Constriction of sciatic nerve in the periforami-

3-4)

44

Rg&re 8-4

Subluxation

TIle ArtIcular LalOII

External concuss ion procedure. (From De Boer.) Manipulative Physio / Ther 4:122, 1981.}

3) Lesions confirmed by manual palpation 4) Long-term experiment (lasting 2.5 weeks) 5) Controls used

cessful induction of most misalignments. Unlike Lin et .I.'s report, radiographic findings were inconclusive.

fNIIIGS: This study, the first in a body of work by DeBoer and his colleagues at the Palmer College of Chiropractic, represents the first attempt to establish a workable, noninvasive, replicable method of inducing an intervertebral joint misalignment. The lesion was induced by [he use of

Study #8 TnU: Changes in nerve physiology in the rat after induced subluxation

an "activator-type" adjusting gun, and palpators were employed afterward to determine if a lesion had been induced, and if so to attempt to agree on its location. lnterpalpator agreement was

JOURNAl; M.Sc. Thesis; summarized in Articula-

reported as fairly high, probably indicating suc-

tions 1983; (Aug) :9-1 O.

AUT1IOR: Israel V

45 AI'At\l: Rat

SUIILlJXOGIMC COMI'IIMNT MOIJ8BI: Misalignment

3) Physiologic and e1ectrophysiologic measures made 4) Controls for surgery used

producing nerve root compression

FNIWGS: This report represents the most elegant fIlTHOIIS: 1) Lesion induced by graded external pressure applied to the spinous process of L6 by a mechanical "drill press-like" device 2) No controls used; short-term experiment 3) Electrophysiologic outcomes

and thorough experiment ever undertaken in the responses of the autonomic system to an induced subluxation. Expanding on the large body of work published by Sato and his colleagues, this "chiropractic version" of his experimenta l model still stands as the best of the animal model studIes.

FNIrIlS: Israel reported that H-wave latencies increased by an average of 15%. This was thought to be indicative of compressive disturbance of th e nerve roots resulting in decreased conductivity. This report showed great promise for a relatively simple model of subluxation-induced nerve disturbance. Unfortunately, no further work by Israel or with her model has been forthco ming.

Study #9 mu:

Sympathetic nervous system responses to mechanical stress of the spinal column in rats

AUTIIOIIS: Sato A, Swenson R JOURNAL: J Manipulative Physiol Ther 1984; 7(3):141-7.

Sato and Swenson reported that, after induction of the lateral flexion stress at TI0-Tll, there were significant reductions in blood pressure that were concomitant with decreases in renal nerve activity. By surgica ll y denervating neighboring joints, and by denervaring the carotid sinus, they showed that these changes were indeed induced by the experimental procedure of mechanically stressing the spine. They proposed that the autonomic disturbance was caused by sensory bombardment from the compressed spinal joint. This likely cook the form of nociceptive irritation of the spinal joint, alt hough the use of an anesthetic joint injection would have confirmed this. They concluded that these findings represented abnormal somatovisceral reflexes resulting from a brief spinal dysfunction. They wisely declined to speculate on whether such a mechanism could lead to "soma to-visceral disorders," but others have improperly extrapolated this conclusion from this srudy.

Study #10

AI'At\l: Ra t

SUBLUXOGIMC COMI'IIMNT MOIJ8BI: Misalignment producing nervous system dysfunction

mu:

Altered metabolic enzyme activities in fast and slow twitch muscles due to induced sciatic neuropathy in the rat

fIlTHOIIS: 1) Surgical procedure; short-term experiment 2) Misalignment produced segmentally by lateral flexion of vertebrae fixed by clamps into a bending rig

AUTIIIIRS: Christiansen J, Meyer J

JOIIINAL: J Manipulative Physiol Ther 1987; 10(5) :227-31.

46 SIIIlUXOGIMC CIM'INNT MOIII.BI: Misalignment

AI'A1Al: Rat

producing altered nerve activity

SIIIlUXOGIMC CIM'INNT MOIII.BI: Subluxogenic nerve compression

METHODS: 1) Manual manipulation (as per Burns et al. )

METHODS:

used to induce vertebral misalignment

1) Surgical procedure; long-term experiment (duration of 2 to 4 weeks). 2) Sciatic constriction model with loose ligatures 3) Physiologic and metabolic ourcomes

2) Surgical implantarion of gastric electromyo· graphic (EMG) monitor. 3) Controls used for surgery and for pain by sham manual stimu lation and cutaneous noci-

ceptive irritation

FNHS: This study expanded on the experiment of Triano and Luttges (see previous discussion).

FNHS: This is the second model employed by

Using the sciatic constriction model, these investi-

DeBoer and his colleagues and is highly reminis· cent of the methods of Burns et al. in the induction of the lesion. In rhis study, however, DeBoer et al. employ a modern approach to exploring the neurally based effects of such a vertebral lesion by monitoring changes in gastric myoelectric activiry with an indwelling EMG monitor. They found inhibitory effects on gastric smooth muscle activiry rhar appeared to be segmentally coordinated. They proposed a mechanism arising from subluxogenic somatovisceral reflex disturbance. This work is similar to the study by Sato and Swenson in that it is based on Sara's work on somarovisceral reflexes, and, in particular, that it

gators studied the end-organ effects of neural compression, which is thought to be caused by foraminal compression. They observed the fol· lowing: (1) changes in the gait of the animals, which they measured using an ingenious method employing dipping the rat's paws in developing solution and having them walk across x-ray film. The resulting footprint analysis allowed the investigators to determine that the experimental limb was protected during gait; (2) changes in nerve conduction velocity sim ilar to that found by Triano and Lunges; (3) enzymatic changes in the denervated muscles, which indicated a shift from fast-twitch to slow-twitch fibers. This latter change is reminiscent of the work of Haldeman (see previous discussion), in that it implicates an alteration in orthograde axoplasmic flow, which would alter the biochemical and metabolic environment of the muscle end organ.

Study #11 TTTlf: Acute effects of spinal manipulation on

demonstrates which organ systems depend more

on spinally mediated responses, and which, like the cardiac system, depend more on supraspinally mediated responses.

Study #12 TTTlf: Surgical model of chronic subluxation in rabbits

AUTHORS: DeBoer KF, McKnight ME

gastrointestinal myoelectric activity in conscious

rabbits

JIIIIWAl: J Manip Physiol Ther 1988; 11 (5):366-72.

AUTHORS: DeBoer KF, Schutz M, McKnight ME AI'A1Al: Rabbit

JIIIIWAl: Manual Med 1988; 3:85-94. AI'A1Al: Rabbit

SlllLUXOGlMC CIM'INNT MOOB.BI: Vertebral misalignment and fixation

47

3 Balle Sc:Ien1IIIc Evidence lor ChIropractic SUbluXation

- ;;..-.-

-.

Flgll'83-5 Surgically induced misalignment (From De Boer, McKnighr. J Manipularive Physio l Ther 1988; II :368.)

1'tE1IOIIS: I ) Surgica l implantation of a metal bar between three thoracic spinous processes, ro misalign the middle one (Figure 3-5) 2) Long-term experiment 3) Controls used

IRMS: This is the third in the series of stud ies reported by DeBoer et a l. In this study, a novel method of inducing a chronic, sustained subluxa-

rion with minimal surgical trauma was devised. This study reported on the method of surgical

induction as well as on its durability in maintaining the misalignment. In addition, observations made of the misa lignment after the surgery also were reported. The conclusion of this report was that a misalignment could be induced and verified

on visual inspection, manual palpation, radiograph ic analysis, and autopsy study. Unfortunately, no outCome effects of this lesion were studied, a lthough the aut hor was made aware, by personal communication with DeBoer, that one of the intended applications of this model was to stud y its effects on the lactation reflex in mothering rabbits. It was theorized that if a lesion could be induced in the TS-T6 segment in one group of mothering rabbits, and compared with a control group, there might be a significant disturbance of lactating behavior, given that the senso ry component of the lactati ng reflex is carried by cutaneous nerves from skin innervated by this dorsal segment. This represents an ingenious test of the theory of central faci litation and disturbed somatovisceral reflexes.

48

Study #13 mu:

Thermographic evaluarion of rars wirh complete sciatic nerve transection

AUTIIORS: Gerow G, Callron M, Meyer JJ, Demchak JJ, Chrisriansen J

JOURNAL: (Abstract). Proc FCER ICSM 199 I; 272-4. AfAQL: Dog

SUIIlIIIIATD\I CIJIIoIIOMNT MOOflBI: Intervertebral joint fixation

r.HlIOOS: JOUIINAl; J Manipularive Physiol Ther 1990;

1) Surgical procedure

13(5):257-61.

2) Dental adhesive glue injected into bilateral

apophyseal joints in the upper lumbar spine

AMMA1.: Rar SUBLUXOGfMC CIJIIoIIOMNT MOOflBI: Sciaric rran-

fI\IKS: These investigators employed a novel

section models severe nerve compression

method of modeling an intervertebral joint fixation. Radiographic and biomechanical stiffness testing demonstrated an increase in the segmenral stiffness, verifying that a segmental fixation was, indeed, induced. This form of fixation, in contrasr to that of the models of Cleveland and DeBoer et aI., involved significantly less invasive procedures and probably could qualify as a valid candidate for a workable long-term experiment. Although increased stiffness was found at the experimental segment, these investigators could nor demonstrate increased stiffness in the entire lumbar spme.

METHODS: 1) Surgical procedure transecting the sciatic

nerve unilaterally 2) Controls used 3) Thermographic evaluation of the hind limbs,

comparing operated with nonoperated

fI\IKS: Thi study attempted ro extend the model of milder, transient nerve irritation to the upper limit of complete transection. In that regard, it is arguable that it was even designed ro study subluxogenic effects, as opposed to those that might arise from a discogenic mechanism, or

onc involving significant nerve rOOt injury. Nonetheless, these authors report that transection did result in increased temperature on the affected side, a resu lt that prompts us to consider the possible autonomic effects of these sciatic irritation models.

Study #15 mu:

Immunologic correlates of reduced spinal mobility: preliminary observations in a dog model

AUTIIORS: Brennan PC, Kokjohn K, Triano JJ,

Study #14 mu:

Spine stiffness measures in a dog model of restricted joint motion

Fritz TE, Wardrip CL, Hondras MA

JOURNAL: (Abstract). FCER ICSM 1991: 118-21. AfAQL: Dog

AUTHORS: Papakyriakou MJ, Triano JJ, Brennan

SUBlUXOGfMC cor.I'OI'BT MOO8fD: Fixarion;

PC

somatovisceral effects

3

BasIc SclIII1IIIc Evidence I... CfIII'OII'lCtIc SUbluxation

METHODS:

49

1) Same as Srudy 14 2) Controls used 3) Long-term experiment (up to 12 weeks)

3) Chronic experiment. 4) Muscle enzymes assayed after killing of animal 5) Contralateral side used as control

ffII\IGS: This study, from the same group as

fI'tM'flS: This srudy is a modification of the ear-

Study 14, employed the dog fixation model to explore immunologic outcomes of a long-term upper lumbar fixation . The reported results were preliminary, but did show evidence of, in the

lier one by Christiansen er aI., with much the same results. In this srudy, rhe results of five preparations were reported, and included "significant decrease of enzyme activiry of both aldolase and lactate dehydrogenase in the flexor digitorum longus muscle and a decrease in lactate dehydrogenase in the gastrocnemius on rhe side with the compressed nerve" as compared with the control side. Other enzyme assays showed trends toward significant alteration, bur the small sample size prevented statistical significance of these findings. As the authors state, "these results suggest that mild, chronic nerve compression, within the physiological range, will produce significant alrerations in end-organ metabolism."

aurhors' own word s, "functional impairment of

the immune system," mOSt likely related to impairment of natural killer lymphocytes. This study provides the first, if only fleeting, evidence to support the notion that the spine plays an important role in the immunologic health of humans. However, before we can accept some of the anecdotal observations regarding clinical improvemenrs in immune-related conditions by chiropractic treatment, a great deal morc work

like this study will have to be done.

Study #18

Study #17

TITU: Enzyme changes in rabbit muscles due to

1TI1.E: Characterization of spinal somatosensory

chronic compressive nerve irritation

neurons having receptive fields on lumbar [issues of cats

AUTlIOIIS: Christiansen JA, Beals S, Burnham G, Magnani M, Urbanek S

AUTlIOIIS: Gillette RG, Kramis RC, Roberts WJ

JOIIINAl: Proceedings of the World Federation of Ch IropractIc Congress, Toronto, Ontario, 1991

JOURNAL: Pain 1993; 54(1 ):85-98. Af&'tW.; Ca t

SUBl.UXOGENIC CIJMIIOMNT MOIIBBI: Motion segSUBlUXOGENIC CIJMIIOMNT MOIIBBI: Chronic, low-

ment tissue pain; central sensitization

level foramina! nerve compression

METHOIIS: .ntOOS: I) Surgical procedures used 2) Miniature compression cuff around one sciarice nerve u~cd to model foraminal compresSIon. Inflated to 40 to 50 Torr for 8 hours daily for 30 days

I ) Surgical preparations 2) Labeli ng and tracing of dorsal horn neurons using standa rd electro physiologic and histochemical techniques to determine the response characteristics of each neuron, its location in the dorsal horn, its receptiveness to deep or

50 superficial stimuli, and its receptive fields in skin and deep tissues 3) Percutaneous injections of algogenic subStances such as bradykinin and hypertonic saline into a variety of motion segment tissues in the lumbar spina l area . These tissues included : Multifidus muscles Facet joint capsules Discs

Dura mater Sympathetic ganglia 4) Characterization of changes in response properties attributable to noxious stimuli of the various lumbar tissues. These changes take the form of expanded receptive fields, unmasking of latent receptive fields, and other manifestations of central sensitization (see following discussion).

FNRS: The work of Gillette, Roberts, and their colleagues represents a major departure from the traditional work reviewed previously. The foremost reason is the sophistication of neurophysiologic investigative technjques, which include peripheral afferent tracing with radiolabeled substances, single-unit electrophysiologic recordings in the dorsal horn, and other e1ectrophysiologic techniques of spinal cord monitOring. Secondly, this investigation (which is made up of a large number of studies, many of which were reported in conference proceedings) takes the form of an attempt to model the pain-inducing effects of the spinal subluxation without resorting to the difficult and cumbersome step of actually misaligning the intervertebral joims themselves. In fact, this study's objective is really the phenomenon of deep somatic pain in the paraspinal area, a topic that has yet to be explo red by any investigators from neurophysiology or any of the other basic clinical sciences. Whereas many of the previo us subluxation studies may have induced pain in the paraspinal tissues, none has done so in a controlled fashion. In some instances, the pain that may have been induced by one experimental maneuver might have been accompanied by other,

more significant, tissue injury. In other instances, compression-related effects of nerve constriction and other manipulations may actually have been pain inducing, creating an unclear picture of experimenta l cause and effect relationships. In this stud y, carefu l a lgogen ic stimu lations were conducted as the primary objective of the experiments, resulting in much new knowledge about the afferent neuronal connections subserving deep spinal pain and of the modifications in response characteristics of the central nervous system to deep somatic pain. Most of the dorsal horn neurons studied by Gillette et al. that received nociceptive input from deep paraspinal tissues were located in the lateral portions of the superficial dorsal horn. Many of these connections were bilateral in the cord. The receptive fields of many of these neurones were comparatively larger than those that innervate less proximal tissues and were certainly much larger than those that innervate truly dista l tissues of the hind foot. Most of these neurons (72%) received input from a large number of sources, including skin, deep somatic tissues, dura mater, and visceral inputs. Gillette et al. have termed these cells "hyperconvergent neurones."

As for modifications of the response properties of these neurons to the various algogenic stimuli, a typical pattern emerged from their studies that is reminiscent of previous work involving tissues from the extremities (20), and that includes slowly increasing after stimulus exciratory discharges, expansion of the receptive fie lds to incorporare further distal tissues, not only ipsilateral but also contralateral to the side of injection, and hyper responsiveness to subsequent noxious and non noxious stimulations. All of these findings are consistent with the current model known as central sensitization, a term proposed by Woolf (21), but that is really reminiscent of the concept advanced by Korr in the late 1940s known as central facilitation (22 ). As Gillette and his colleagues point out, these neurophysiologic findings are the most likely mechanisms that underly a great variety of c1ini-

3 Balle SCIentIIIc Evldencllor ClI......·1CtIc SUbmaIlon cal phenomena associated with deep somatic pain. These findings provide an explanation for the diffuse and poorly localized character of spinal pain, and for the phenomenon of referred pain. They provide a basis for understanding why spinal pain might be exacerbated by subsequent pain arising from nonspinal sites, and, possibly, the reverse situation. In other words, these findings provide for a great advance in our understanding of subluxogenic pain, which is the basis for understanding of the great variery of spinal pain syndromes so commonly treated by chiropractors.

Study #18 mu:

Excitatory effects on neck and jaw muscle activity of inflammarory irritant applied ro cervical paraspinal tissues

AIITIIOIIS: Hu JW, Yu X-M, Vernon H, Sessle 8J

JOUIINAl.: Pain, 1993.

51

4) EMG monitoring using unipolar leads placed in the following muscles: (1) ipsilateral masseter, (2) ipsilateral digastric, (3) ipsilateral trapezius, (4) ipsilateral deep paraspinal, (5) contralateral deep paraspinal.

1ItI'CS: This study takes an approach similar to that of Gillette et aI., in that the proposed paininducing effects of the subluxation are modeled directly using an inflammatory algogenic substance, mustard oil, which is a known C-fiber irri-

tant (23). Although Gillette et al. employ more direct measures of the nociceptive effects (that is, by investigating response properties of dorsal horn neutons), we employed an indirect method based on the pain-spasm theory (24). This is the first study, to our knowledge, that demonstrates the very commonly observed clinical phenomenon of deep paraspinal somatic pain eliciting muscular excitation. Of great interest in this study was the finding of excitatory effects in muscles that were not only local (for example, the ipsilateral deep paraspinal muscle, which showed the largest initial response and the most prominent second-phase response), but also distant, in several ways. First, excitatory effects were seen in

AM't'IAl: Ra t

SUIIlUXOGIMC CIM'INNT MOOEUD: Intervertebral joint pain

Pt'ITIIOOS: 1) Surgical procedure 2) Injection of inflammatory irritant (mustard oil) into the pararticular space around the C2-C3 joint on the left, and into the deep sub-

the contralateral deep paraspinal muscle, which were almost identical to those in the ipsilateral muscle, with the exception of the slightly smaller magnitude of the increased EMG output. Secondly, excitatory effects were observed also in a superficial muscle (the trapezius) and in distal muscles thac surround another articulation (the

temporomandibular joint), but that are related by their shared nociceptive innervation by the trigeminal nucleus subcaudalis (25) .

occipital muscle-rectus capicus posticus

major--

Components of Subluxation Modeled By Animal Studies

• Facet compression • Paraspinal deep somatic pain • !ntervenebral foraminal nerve root compres· sian • Fixation

• Hypermobility

Other studies have attempted to actua ll y model the components of the subluxa ti o n itself: compression in the intervertebral foramen, paraspinal pain, or fixation of the motion segment. In the former case, sciatic liga tion has been the chief method employed, although Christiansen et al.'s most recent work em ployi ng a miniature pressure cuff is quite innovative. In every case, the compressio n-related effects predicted by the subluxation theory have been demonstrated, including reductions in conduction velocity and in axoplasmic flow, as well as enzyme changes in muscle end o rgans. In the case of pain-related effects, both mechanical a nd chemical methods have been employed. Mechanical methods include facet compression and misal ignment, whereas chemical/infl ammatory methods have employed a lgogenic injections of bradykinin, mustard o il, and hypertonic saline. In these models, deep spi nal pain has been shown to have profo und effects on neurophysioiogically based pheno mena such as response characteristics of dorsal horn cells and muscle activity. In the one case in which fixation was induced without accom panying misalignment (by Brennan, Triano, an d their colleagues), interesting systemic effects of the induced hypomobility were demonstrated, which certainl y prompt further in vestigation. The box at the top of p. 54 lists the different outCome measures used in this set of studies. When

54

>

Animal Model Studies: Measures and Outcomes Used

!MIl

Histology of joints and nerves Radiographs of the spine Pathologic function of nerves o EMG of paraspinal muscles Dlltall o o o

• Autonomic nerve function

Homeostatic rellexes Organ pathologic effects Changes in cutaneous receptive fields H-Reflexes Conduction velocity Axoplasmic flow Trophic changes in muscles Motor behavior

o o o

o o o

o o

combined with the great variety of techniques used to experimentally induce or model a subluxation, one can only be impressed by the breadth of technical innovation and sophistication that has been employed by the profession's basic scientists. Their efforts have been rewarded by the accumulation of a database that is remarkable for its theoretical and experimental consistency. in virtually every instance, some aspect that has been predicted by the subluxation theory has been verified. The box below lists some of the strengths and weaknesses of this body of work.

>

Animal Models in Chiropractic Science

• Numerous investigative groups o Innovative methodologies devised o Conceptual consistency in experimental approaches o Theoretical consistency in experimental findings ".pU. . • No sustained lines of investigation • No comprehensive line of investigation

o No replications o No clinical implications o Very few conferences/no "body of literature" o Growing concern over animal welfare may make long-term experiments difficult

Unfortunately, as this box shows, there are some compelling concerns that exist after some eighty years of investigation. The chief among these is that this body of work has not been crystallized in the collective consciousness of the profession. The profession, it seems, is either still "fixated on" or feels more satisfied with its conceptual models and its elaborate speculative pictures than with the pursuits of morc basic scientists, who seek to depict or study subluxation as it really occurs. The profession's research agenda (which, thankfully, has finally come into existence) seems far more preoccupied with clinical matters than with those of its basic science. This may suffice for the musculoskeletal domain, because, as of the writing of this chapter, the pathologic model of low-back pain is in poor repute, with the functional, patient-oriented model predominating. In this kind of atmosphere, chiropractic therapy can flourish because demonstrating the efficacy of a treatment is more important than elucidating the mechanism that underlies it. However, for nonmusculoskeletal conditions, the opposite situation pertains. It is my opinion that dozens of clinical trials can occur in such areas as the chiropractic treatment of asthma, dysmennorhea, hypertension, etc., but they will all be relegated to insignificance and be dismissed as large-scale exercises in the placebo effect if a credible, va lid biologic mechanism that links dysfunction in the spinal column with dysfunction in organ systems cannor be provided. This is the task that only the profession's basic scientists, in their pursuit of the scientific basis of subluxation, can accomplish.

References I. Ganerman MJ . Chiroprac1ic management of spme related disorders. Baltimore: Williams and Wilkins, 1990.

2. Brantingham jW. A survey of the luerarurc regardmg the

a

3.

4.

5.

6.

7.

8.

9.

10. II.

12. 13. 14.

BaaIc ScIen1IIIc Evidence

behaviour, pathology, etiology and nomenclature of the chiropractic lesion. J Ch iro 1985; 22(8):65- 70. Lanrz CA. The vertebra l subluxation complex. Part 1 t The neuropathological and myoparhoiogica i components. Ch;
Interrater Ma lposition Muscle tension Pain provocation Inrrarater

62

SUbluxation

TIle ArtIcular LesIon

exam in ers are self-consistent but cannot agree, then at least one rater must be consistently in

error. Also, a ny clinica l findings that cannot be replicated by others are always considered suspect.

actually depend on individual palpatory procedures? How do chiropractors weigh the evidence from a variety of adjustive indicators? Are palpatory rests morc valuable in certain patient popula-

tions than in others? Do chiropractors effect successful adjustments and patients show clinical

StaUc PalpaUon

improvement in spite of the diagnostic tests per-

Ten studies appear in the literature addressing static palpatory procedures (Table 4-6): three on

formed? Finally, we must ask ourselves if the

the cervical region, one on the thoracic spine,

eight on the lumbar region, and three on the sacroi liac joints. Inrerexaminer concordance of

specificity assumption led us astray from investi-

gating the reliability of palpation in a context relevant to the actual biomechanical and clinical effects of manipulation on the body.

vertebral malposition (0.00) and muscle tension (0.07 to 0.20) have been found to be little more than happenstance (Table 4-5) (12,45,50). How-

Improving the Reliability 01 Palpation

ever, some results for provocative pain over the spinous processes and paravertebral soft rissue

There is a rich supply of literature on the need for en hancing the reliability of diagnostic tests,

have been encouraging (0.20 to 0 .69) (12, 45, 50). There have been no intraexaminer reliabiliry studies on static palpation.

sources of inconsistency, and recommendations

for reliability improvemenr (Table 4-7). This lirerature is as valuable to the practicing clinician as it is to clinical researchers.

Conclusion

Why Bother?

Although the reliability of palpation appears discouraging, a ll is far from lost, as will be seen

We must first ask ourselves why improving

in

the

next section.

Many

interesting

and

consisrency is so important. After all, experience

provocative questions have arisen from more

tells us that we ca n successfully identify manipulable subluxations and make our patients better.

than a decade of research. For example, to what degree does the clinical decision-making process

Unfortunarely, even accurate recollection of our experience can lead us to wrong conclusions

about the effect of diagnostic tests on patient outStatic Palpation Reliability Studies

Author DeBoer et al. (56) Boline et al. (45) Nanse! and Jansen (64) Owens (67) Leboeuf et al. (66) Jansen et al. (68) Keating et.1. (12) Byfield et al. (69) Byfield et al. (70) Boline et al. (50)

Year

1985 1988 1988 1988 1989 1990 1990 1992a 1992b 1993

Reglo.' C L C,T,L,SI ~ ~

L L,SI L L,SI SI L

·C, cervical; T, rhoracic; l, lumbar; 51, sacroiliac.

Clinical Judgment and Reliability Literature '..

, •

.~.

",:I'

'J._.

,

--~.

.'

Author Deparunent (52)" Department (53) " Feinstein (71) Feinstein and Kramer (72) Feinstein (73) Sackett et aJ. (33 ) Wright and Feinstein (51)

.-

'

. . •

"'7

Year

1980 1980 1964 1980 1987 1991 1992

· Departmenl of Clinical Epidemiology and Biostatislics, McMaster UniverSity. Iinmiiton. Ontario, C.1nnda.

4 Palpatary DtalilOlla 01 SUbluxation come (33), and there are several good reasons why it is imperative that reliability of palpatory procedures be improved (51). Our first motivation is the justification of

using palpatory procedures in the first place. A test in which the findings cannot be replicated will always be called into question. How can we be sure that we can identify a manipulable subluxation; how can we be sure that a patient really has a motion restriction o r malposition and that it responded to treatment? Furthermore, poor

reliability implies that a test performs little better than guesswork and as such contributes on ly marginally to the decision-making process (34); why bother wasting the time and effort? An unreliable test can hardly be justified as cost-effective. Improving reliability can also enhance the accuracy of a rest; an unreliable test can never be

accurate (51). Improvi ng accuracy can lead to increased efficiency of care because false-negative findings can lead to underadjusting, and falsepositive findings can lead co excessive intervention. Finally, better consistency increases our con-

fidence in finding manipulable subluxations and monitoring changes in clinical status.

SOII'C8I 01 n:onslstancy Three sources of test inconsistency are discussed in the literature: the exam ined, the examination, and the examiner (51, 521. Different clinical findings may be attributable to variability in the procedure. For exa mple, imersegmenral orientation and motion characteristics may vary greatly in the various patient positions used to perform the examination: sitting, supine, prone, or side posture. Physicians also use different landmarks to locate malposition and sites of provocative pain and use different methods for evaluating quality of motion, joint play, and end feel. Even when the same procedure is used, there is variability in its performance. Physicians hold patients in slightl y different positions or palpate with varying degrees of force. Procedure and performance being equal, inconsistency still arises from variability in interpretation: differences in

63

principle and perception. Where do individual clinicians draw the line in identifying manipulable subluxa tions from hard end feel or joint play restriction; what constitutes a malposition? Perception also can vary with physician expectation, alertness, and mood. After an adjustment, what chiropractor is not confident that a manipulable subluxa tion has been rectified?

What we Can Do Standardization There are several important trategies for improving the reliability of palpatOry procedures (Box below) (53). Probably the most difficult to implement is standardization of test procedure, performance, and interpretation. Chiropractic colleges need to make a concerted effort to research and develop instructional methodologies that foster consistent terminology and palpation outcomes. Ir has been suggested that improved standardization of techniques and enhanced ability to evaluate psychomotor ski lls may be faci litated by the use of mechanical devices to assist in quantitative feedback by the quant.ification of manual forces (8,54,55). Examples include bathroom scales (8), pressure plate with osci lloscope (55), and a mechanical spina l model with simulated fixations (54). IntructOrs a lso must emphasize to their students the potential influences of perception a nd expectation on clinical findings. Ambiguity not o nl y affects measurement consistency but also undermines the ability of chiropractors wit h diverse ideologies and treatment strategies to communicate with each other.

>

Steps To Be Taken to Improve Reliability

1. Standardization of test procedures 2. Repetition of test findings 3. Corroboration of test findings 4. Identification of suitable patient subpopulations

5. Reevaluation of specificity assumption

64

Subluxation TIle Articular lesion

Repeated Tests It is well known that for a teSt with nonzero reliability, the reliability of the average finding of test repetitions is greater than the reliability of a single evaluation (29-31). For example, when repeated tests are conducted independently (examiner blinded to previous results ), if the ICC = 0.50 for a single measurement, the reliability of two evaluations would be ICC = 0.67, and for three assessments, ICC = 0.75. Although repeated palpations are not blinded in clinical practice, they shou ld reduce diagnostic error. However, because of the likel ihood of some consistent error, the physician should regard high self-consistency with caution (36). Corroboration Another strategy for strengthening rhe reliability of manipulable subluxation detection is the use of diagnostic test regimens (42). Reliabiliry mighr be increased by using multiple tests for the evaluation of a si ngle palpatory dimension' of the subluxation (for example, motion, alignment, or palpatory pain ). The evaluation of mulriple pal patory dimensions as well as the inclusion of other clinical information is also strongly recom-

mended to avoid false-negative results. Research into the value of multitesr regiments is in irs early stages ('12, 45, 50). Further investigation is required to clearly identify individual dimensions of the subluxation and to establ ish regiments of related tests for evaluation of rhese

dimensions. Identification of Suitable Patients It is possible that various palpation techniques are more su itable fo r certa in subpopulations of patients than for others. These subpopulations could be identified through studies of carefully defined homogeneous groups of patients : probably parients with more severe and extensive problems. It also must be pointed our that, in genera l, concordance depends on the prevalence of the entiry being assessed (3 0, 34). For patient populations wit h a dearth of manipulable subluxation, it

is difficult for any test to perform better than guessing that the patient is normal at any particular segmental level. Reliability will inevitably be low in this case, and the contribution of palpation to the cl inical evaluation of the patient will be minimal.

Challenging the specmclty AssumptIOn With two exceptions (26, 56), reliability has been exclusively evaluated within the context of the specificity assumption. Whar we muSt ask ourselves is whether this precept is clinically valid: are we really investigating the re liability of detecting what we actually treat, and if not, are we underestimating the reliabi lity of our adjusrive indicators (44)? The specificity of the vertebral conracr rna y nor be necessary for correction of the "truc" underlying manipulable subluxation. Alternatively, the specific adjustment of different manipulable subluxations may have the same clinical effects; two chiropracrors may rightfu ll y treat different segments. If contact specificity is nor valid, examiners would not have to agree on specific segments bur only on a specific region to have the same clinical outcome. In this case, "regional " rather than "segmental" concordance in the site of an adjustment might be a sufficient condition to establish acceptable interexaminer reliabiliry of palpatory procedures. If adjustment specificity is not required to treat a clinical condition, however, self-consistency may be paramount and intraexaminer concordance the key to the reliability of pa lpation (the concerns listed previously norwithstanding) . Clearly it is easier to find agreement over a wider range of vertebral segments and with oneself than it is to find interexaminer agreement segment by segment. However, enhancing reliability is no justification for abandoning rhe specificiry assumption a priori . There is no biomechanical model or clinical evidence to suggesr how big the zone of agreement might be or how it might vary for different regions of the spine or different clinica l conditions.

4 Palpatory 0iagI1OIIs of Uluxa1lon

Future Research The goal of investigators must be to represent the adjustive decision-making process as realistically as possible in measurement evaluation research. Clinically relevant reliability assessment must include the study of de facto test regimens as well as the eva luation of indi vidua l procedures. The viability of the specificity assumption will be investigated in part through studies of the biomechanical relationship of the spinal contact with the motion segments being affected. Further research mUSt be conducted ro establish the clinical usefulness of palpatory procedures (32, 33) . The validity of palpation ro detect manipulable subluxations will be measured indirectly in the short term through the assessment of its theoretical properties (construct validity); these include the correlation of palparory findings with patient symptomatology, other diagnostic findings, ndjustive intervention, and treatment ourcomes. Ultimately, the utility of palpation must be evaluated: is the patient better off for having had the procedures performed'

References I. Bergman TF, Peterso n DII. Lawrence OJ. Chlropracric technique. New York: Churchill Livingstone, 1993. 2. Faye LJ. Wiles MR . Manual cxanunation of the spine. In: J laldcman S; cd. PrinCiples and practice of chIropractic. 2nd ed. San Matco, Gtlifornia: ApplclOl1 and Lange.

1992: .101-18. l. Gatterm.ln MI. Chiropractic management of spine relared disorders. Baltimore: Williams & Wilkins, 1990: 118-122, 142-146, 187- 197,222-229. 4. Plaugher G, Lopes MA , cds. Textbook of clinical chiropractic, Baltimore: Williams & Wilkins. 1993:

86-91.

10.

II. 12.

1]. 14.

15.

16. 17.

18.

19.

20.

21. 11. 23.

24. 25.

5. Schiotz Ell, Cyriax J. Manipulation past and present.

London: Willi:tm Ilclnemann Medical Books, 1975: 6.

7. 8.

9,

.\-27. Anderson R. Spinal mampulation before chiropractic. In : IialdcI113n S, ed. Principles .md practice of chiropractic. 2nd cd. San Mateo. C... hfornia: AppiNon and Lange, 1992. Seal MC Perception through palpation. J Am Osteopath A"oc 1989; 89(10): 1334-1352. KeaungJ, Matyas TA, Bach TM . The effect of training on phYSical therapists' ablliry to appl), specified forces of pal · pallon. Ph ys Ther 1993: 73 ( I): 45-53. Magee OJ: Onhopedic physical assessmcni. Philadelphia:

26.

27. 28.

29.

65

WBSaunders, 1987: 14-15,38-40,83-87,101-3, 131-7, 160-, 196, 197,231-7,256-9,30 1-7,343-52. Goble DO. Medical evaluation of the musculoskeletal sy~­ (eln and common integument relevanr to purchase. Vct elln North Am Equme Pract 1992; 8(2): 285-302. Gregory AA. Spmal treatment science and technique. Oklahoma Cit): The Palmer-Gregor) Conege, 1912: 345-6. KeaungJC, Jacobs GO, Bergmann T~, et al.lnrerexamIller reliability of eight evaluative dimensions of lumbar ~egmental abnormality. J Mampulatlve Physiol Ther 1~90; 13:46.1 -70. Palmer DO. The science an and philosophy of chiroprac£Ie. Portland, Oregon: Portland Prmnng I-Iouse, 1910: 10. Palmer BJ. The Philosophy science and art of ncrve nacing. In: thc science o f chiropractic. Vol. 6. Davenport, Iowa: Palmer School of Chiropractic, 191 J: I 1-18. C),riax E. On the rechnique of nerve palpation by nerve "friction." Review of Neurology & PS)'chlatry (G B) 1914; 12:148-51. Gillet H. Vertebral fixations, an mtroducnon to movement palpation. Ann Swiss Chlro Assoc 1960; 1:30. Gillet H, Llckens M. A further study of spmal fixation s. Ann Swiss Chiro Assoc 1969; 4:41. Gillet H. Liekens M. Belgian chiropractic research note!>. HuntingtOn Beach, California: Motion Palpation Instilutc; 1981 . Faye LJ. Motion palpation of the spine. From MPI notes and review of literature. Huntington Beach, Caltforma: Motion Palpation Institute, 1981. Schafer RC, Faye LJ. Motion palpanon and chiropractic technique: prinCiples of dynamic chiropractic. Huntingwn Beach, Caltforma: Motton Palpation Insmute, 1989. ACA Council on Technique. Chiropractic terminology: A report. JAm Choro Assoc 1~88; 25110):46. Bryner P. A survey of indications: knee manipulation. ChiroTcch 1~89; 114): 140-145. Bryner P, Bruin J. Extremity jOint technique: Survey of the status of technique teaching in chiropracric colleges. Chito Tech 1991; 311 ):30-32. Breen A. The reliability of palpation and orher diagnostic methods. J Manipulative Physiol Thcr 1992; 15:.14-56 . Love RM, Brodeur RR. Inter- and mrra-examiner reliability of marion palparion for rhe thoracolumbar spme. J Manipulative Ph)'siol Ther 1987; 10: 1-4. Moorz RD, Keating JC, Kantz HP. Intra · and Inter-exa mmer reliability of passive morion palparlon of the lumbar spine. J Manipulative Physiol Ther 1989: 12:440-5. Panzer D. The reliability of lumbar motion palpation. J Manipulative Ph)'siol Ther 1992; 15:518-24. Jull G, Bogduk N, Marsland A. The accuracy of manual diagnosis for cervical zygapophyseal Joint pain syndromes. MedJ Aust 1988; 148:133-6. s.... rrko JJ, Carpenter Wf. On the methods and theory of reliability. J Nerv Ment DIS 1976: 163:307-1 7. t

66 30. Haas M. Sransrical methodology for reliability studies. J Manipulative Physiol Ther 1991; 14:119-32. 31. Kramer MS, Feinstein AR. Clinical biostaristics. L1V. The biostatistics of concordance. Clin Pharmacal Ther 1981 j 29,111-23. 32. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilron, Ontario. How to read clmical journals. II. To learn about a diagnostic teSt. Can Med AssocJ 1981; 124,703-9. 33. Sackett DL, Haynes RB, GuyaH GH, Tugwell P. Clinical epidemiology: A basic science for clinical medicine. 2nd ed. Boston: Little Brown, 1991. 34. Feinstein AR, Ciccheni DV. High agreemem but low kappa. I. The problem of two paradoxes. J Clin Epidemiol 1990; 41 (6P43-49. 35. Haas M. The reliability of reliability. J Manipularive Physiol Ther 1991; 14,199-208. 36. Rosner S, Willen WC, Spiegelman D. Correlation of logistic regression relative risk estimates and confidence intervals for systematic within-person measuremem error. AMJ Ep,demiol1989; 8,1051-1069. 37. Fleiss JL. Estimating the accuracy of dichotomous judgments. Psychometrika 1965; 30(4):469-79. 38. Fleiss JL. Cohen J. The equivalence of weighted kappa and the intraclass correlation coefficient as measures of reliabihry. Ed Psychol Meas 1973; 33:613-19. 39. Fieiss JL. Statistical methods for rares and proportions. New York: John Wiley & Sons; 1981 :212-36. 40. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics 1977; 33,159-74. 41. Rosner B. Fundamemals of biostaristlcs. 2nd ed. Boston: Duxbury Press, 1986. 42. Haas M. Interexaminer reliabiliry for multiple diagnostic test regimens. J Mampulative Physiol Ther 1991; 14,95-103. 43. Reference deleted. 44. Haas M, Peterson D, Hoyer D, Ross G. The reliability of muscle testing response to a pro\'oca tive venebral challenge. Chiro Tech 1993; 5(3),95-100. 45. Boline PO, KearingJC, Srist J, Denver G.lnterexaminer reliability of palpatory evaluation of the lumbar spine. Am J Choro Med 1988; U-II. 46. Carmichael JP. Inter- and intra-examiner reliability of palpation for sacroiliac joint dysfunction. J Manipulative PhYSlol Ther 1987; 10,164-171. 47. Mlor SA, King RS, McGregor M, Bernard M. Intra and interexaminer reliablhry of motion palpation in the cervical spine. J Can Chiro Assoc 1985; 29: 195-8. 48. Mior SA, McGregor M, SchUl AB. The role of experience m clinical accuracy. J Manipulative Physiol Ther 1990; 13,68-71. 49. Nansel 0, Peneff AL, Jansen RD, et al.: Interexaminer concordance in detecting joint-play asymmetries In the cen'lcaJ spmes of othenvise asymptomatic sublects.

J Manipulative Physiol Ther 1989; 12:428-433. 50. BollOe PD. Haas M, MeyersJJ. Kassak K, Nelson C, Keating J. Interexaminer reliability of a multi-dimensional index of lumbar segmental abnormality. Part II. J Manipulative Physiol Ther 1993; 16 (6) :363-74. 51. Wright JG, Feinstein AR. Improving the reliabilLty of orthopaedic measurements. J Bone JOint Surg 1992; 74S,287-91. 52. Departmenl of Clinical Epidemiology and Biostatistics, McMaster Unlversiry, Hamilton, Onrario. Clinical disagreement. 1. How often It occurs and why. Can Med Assoe J 1980; 123,499-504. 53. Departmenl of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario. Clinical dis· agreement. II. How to avoid it and how to learn from one's mistakes. Can Med AssocJ 1980; 123613-1 7. 54. Harvey 0, Byfield D. Preliminary studies with a mechanical model for the evaluation of spinal motion palpation. Clin S,omech 1991; 6(2P9-82. 55. Lee M, Moseley A, Refshauge K. Effect of feedback on learning a vertebral jOint mobilization skill. Phys Ther 1990; 70(2),97-104. 56. DeBoer KF, Harmon R, Tunle CD, Wallac~ H. Rehabillty study of detection of somatic dysfunctions m the cerVical spine.J Mampulatlve Physiol Ther 1985; 8:9-16. 57. Alley JR. The clinical value of motion palpation as a diagnostic tOol: a review. J Can Chiro Assoc 1983; 27,97-100. 58. Russell R. Diagnostic palpation of the spine: a review of procedures and assessment of their reliability. J Mampularive PhYSlol Thor 1983; 6,181-183. 59. Dishman RW: Static and dynamiC components of the chiropractic subluxalion complex: a literature review. J Mampulatlve Physiol Ther 1988; 11 :98-1 07. 60. Keatmg Jc. Interexaminer reliability of motion palpation of (he lumbar spine: a review of the chiropractic hterawre. AmJ Chiro Med 1989; 2,107-110. 61. Wiles MR. Reproducibility and II1terexaminer correlation of motion palpation findings of the sacroiliac Joints. J Can Chiro Assoc 1980; 24,59-69. 62. Bergstrom E, Courtis G. An inrer- and intra-examiner reliability study of motion palpation of the lumbar spine In lateral nexion in the seated position. Eur J Chiro 1986; 34,121-141. 63. Rhudy TR, Sandefur MR, Burk JM. Interexamlncr/ inrertechnlque reliability in spinal subluxation assessment: a multifactorial approach. Am J Chlro Med 1988; 1,111-14. 64. Nansel DO, Jansen RD. Concordance between gaivalllc skin response and spinal palpation findLngs In pain-free males. J Mampulative Physiol Ther 1988; 11:267-272. 65. Herzog W, Read LJ, Conway PJ, et al. Reliability of motion palpation to detect sacrOIliac loint fixations. J ManipulatIVe Physiol Ther 1989; 12:86-92. 66. Leboeuf C, Gardner V, Carter AL, Scott TA. Chiropractic

4 palpatory ___ 01 SUbluxlllon

67. 68.

69.

70.

exa minatio n procedures: :J. reliability a nd consistency srudy. J Au .. Chi ro Assoc 1989; 19, I 0 I- I 04. Owens E An objective measuremem of muscle tone. Chiro Res J 1988; \,34-42. Ja nsen RD, Nansel DO, Slosherg M. Normal parasp inal tissue com pliance: the reliabi liry of a new cl inical a nd experi menta l instrument. J Manipul ative Physiol Ther 1990; 13,243-246. Byfield D, Hu mphreys K. Inrer- and inter-examiner reliability of bony landmark identifica tion in the lumbar spi ne. Eur J Chiro 1992; 40:13-17. Byfield DC, Mathiasen J. Sangren C. The reliability of osseous la ndmark palpation in the lumbar spine and

67

pelvis. Eur J Chiro 1992; 40,83-88. 7 1. Feinstei n AR Scientific methodology in clin ica l medicine. IV. Acquisition of clinical da ta. Ann intern Med 1964; 6 1(61, 1 162-93. 72. Feinstein AR, Kramer MS Clinica l biostatistics. L1L1. The architectu re of o bserver/method va ria bility and other types of process resea rch . Clin Pharmacol Ther 1980; 28(41,551"';;3 . 73. Feinsten AR Clinimetrics. New H aven, Connecticut: Yale University Press, 1987. 74. Jansen RD, Nansel DO. Diagnostic illusions: the reliabi liry of rando m chance. J Manipulative Physio \ Ther 1988; 1\,355"';;5.

The Role 01 Radiography in Evaluating Subluxation John A. M. Taylor

KeyWords

Static radiography, spinographic analysis, functional radiographs

After reading this chapter you should be able to answer the following questions:

Question #1

What are the common clinical reasons for taking radiographs?

Question #2

What are the clinical findings that indicate functional radiography may be useful?

Question #3

What is the procedure for identifying cervical flexion-extension motion abnormalities?

5 The Role 01 Radography In Evaluating Subluxatloo

>

T

he role of radiography in the evaluation of the chiropractic spinal vertebral subluxation has evolved considerably over the years (1,2). Both static and functional radiographs are used in chiropractic to eva luate posture and biomechanics. In clinical practice, emphasis on one

method or the other appears to depend largely on the individual practitioner's concept of a subluxation. Although some chi ropractors view subluxation as a purely static phenomenon of vertebral misalignment, more recently an increasing num-

ber of chiropractors have begun to view the subluxation as a more dynamic, functiona l concept encompassing abnormalities of articu lar motion (3-5) .

Today, chiropractors use radiography for several reasons. Shennan (6) identifies the following clinical reasons for taking radiographs: 1. 2. 3. 4.

To establish a clinical (pathologic) diagnosis To evaluate biomechanics and posture To identify anomalies To screen for conrraindications

5. To monitor degenerative processes Nonclinica l reasons for taking radiographs are inappropriate and include (6,7) : 1. Financial ga in for the practitioner

2. Force of habit 3. Medicolega l advantage 4. Patient education Current epidemiologic studies examining the role of lumbar spine radiography question the value of taking radiographs for many clinical situations. Howard and Rowe (8) and Deyo and Diehl (9) recommend severa l criteria for selecting low-back pain patients for radiography (see box above). Some chiropracrors argue that chese recommendations ignore factors unique to the ch iro-

practic approach to stead Clinic Staff. spme radiography. 1-8). For instance,

69

patient care (6,10, and GonGonstead concepts on fu ll Unpublished position paper, Gatterman (11) identifies 31

Spine Radiography: C linical Indications for Patient Selection

• • • • • • • • • • •

Patients older than 50 years Significant trauma Neuromotor deficits Unexplained weight loss Suspicion of ankylosing spondylitis Drug or alcohol abuse History of cancer Corticosteroid use Increased temperarure, above 100°F Diabetes or hypenension Recent visit for same problem and not improved • Patients seeking compensation for back pain Pllyllcal FItIdIIp

• • • • • • • • • • • •

Dermopathy (psoriasis, melanoma) Cachexia Deformiry and immobiliry Scars (surgical, accidental) Lymphadenopathy Localized pain, tenderness, spasm Motor or sensory deficit Elevated erythrocyte sedimentation rate Elevated acid or alkaline phosphatase Positive rheumatoid faeror Positive HLA 827 Serum gammopathy

Adapted from Dcyo and Diehl 1986 (9) and Howatd and Rowe 1992 (8).

conditions that contraindicate or require modifi-

cation of spina l manipulation and suggests that, in at leaSt 20 of those conditions, radiographic examjnarion is pan of the standard of practice for establishing the diagnosis. The fact remains that radiography should never be used as a general screening procedure without specific clinical indication (9,12) . Howe (13) stresses that routine o r stereoryped methods of radiographic examination do not serve the best interests of the patient.

70 The following discussion focuses on rhe indications and limitations of some of the more com-

monly employed sraric and funcrional radiographic procedures employed in rhe evaluarion of posture, biomechanics, and misalignment.

Static Radiography and Spinographic Analysis Spinography, the procedure of analyzing spine radiographs for postural and structural abnorma lities, dares from 1910, when ir was firsr introduced ar Palmer School of Chiropracric by Dr. B. J. Palmer (1). Marking radiographs ro identify misalignments was a natural extension of the

popular sraric concepr of subluxarion in rhe early 1900s. From 1918 until 1936, full-spine radiographic techniques were developed (1,2,14) . Texts on chiropracric spinography have been published by Thompson (15), Hildebrandr (16), and Winterstein (17). [n addition, technique systems using spinographic analysis have been developed by several chiropractors, including Clarence C. Gonstead (10,18) and Hugh B. Logan (14,19). The validity, reliabiliry, and clinical relevance of many spinographic methods have been srudied . The fundamental criticism of measuring misalignments on radiographs is rhe ptoblem of anatomic asymmetry. Asymmetric developmental anomalies are common and can simulate [rue misalignments

(20) . The role of full-spine radiographs in chiropracric analysis remains conrroversial (2). Opinions held by chiropractors vary widely and include those who consider full-spine radiography a routine procedure to those who consider it an overused procedure that never should be used. The lirerarure suggesrs, however, rhar wirh proper patient selection, careful attention to technical derail, and use of several rechnologic advancements, full-spine radiography is a diagnosric and analytic procedure wirh an acceptable risk/benefit ratio (2) . The circumstances in which full-spine radiographs might be preferred over sectional radiographs are as follows: (1) cases in which

clinical examination discloses the need for radiography of several spinal secrions; (2) cases in which severe postural distortion is evident; (3) for scoliosis evaluation after clinical assessment; (4) cases in which a mechanical problem in one spinal area adversely affects other spinal regions; (5) to specifically evaluare complex biomechanicalor postural disorders of the spine and pelvis under weight-bearing conditions (2,16,21,22). Many chiropracrors agree that full-spine radiography should be reserved for evaluating scoliosis after a thorough clinical evaluation . Scoliosis measurement using the Cobb merhod is well established (Figure 5-1) . This measurement is reported to be accurate to within 2.8 0 to 11 0 (2325). Mehta concluded thar rotation of up to IS' is necessary for clearcut identification of vertebral rotation on scoliosis radiographs (26). This observation calls into question many of rhe methods used to measure millimetric changes in vercebral rotation. A high correlation has been demonstrated between Cobb angles measured on posteroanterior (PA) and anteroposterior (AP) radiographs (27) . Conflicting evidence regarding the reliability of pelvic spinographic analysis has been reported. Plaugher and Hendricks (28) found excellent interobserver and inrraobserver reliability, and Phillips (29) found very little consistency berween the various methods used. Many errors arise from faulty patient positioning (30). Leg-length inequality (LLl) can be measured reliably from spine radiographs (31), but most authors agree that specialized orthoradiography or clinical examination is morc accurate in the

assessment of LLl (Figure 5-2) (31-34). Some chiropracric analytical procedures are based on the premise that static misalignments can be confirmed by radiography and rhat these misalignments can be corrected by chiropractic adjusrments. In one large study (35), rhe only demonstrable postmanipulation change was a 340/0 reduction in retrolisthesis. No posttreatment change was observed in cervical lordosis, sacral

base angle, lumbar lordosis, scapular angle, or Cobb's angle.

Ii 1118 Role 01 Radiography In Evaluating SUbluXation

~

5-1 Scoliosis Measurement: Cobb's Angle. Cobb's angle is obtained from frontal (AP or PAl spine radiographs by constructing lines along the end plates of the end vercebra located at the superior and inferior

extremes of the scoliosis. Perpendicular lines are then

constructed and the intersecting angle is then measured. This angle is used ro assist in managemenr

71

~ 5-2 Scoliosis Secondary ro Leg Length Inequality. This 35-year-old woman sustained a severe femur fracture when she was 12 years old, resulting in significanc growth retardation of one lower extremiry. This has resulted in obvious disparity in [he heights of the femoral heads and iliac crests as well as scoli osis.

decisions and as a comparison to previous and future

studies to monitOr scoliosis progress. This measurement is accurate to within 2.80 to 11 °.

This study (35) raises the question of the clinical validity of spinographic ana lys is. Phillips et a l. (36) concluded that spine radiographs, analyzed

by measurements, have minimal value in predicting the presence or absence of low-back pain compla ints. Mootz and Meeker (37) and Phillips agree that the use of rad iography for biomechanica l (postural) eva luation req uires further c1arifica-

tion and research. Evidence is lacking that these parameters demonstrate any clinical significance. Owens' review of the literature and summary of the role of line drawing ana lyses of static cervical radiographs used in chiropractic (38) is consistent with those of Phillips et al. (36) and Mootz a nd Meeker (37). Owens concludes that, although some studies demonstrate reliabi lity of some of these procedures, the accuracy and clin ic significance remain in question. "The major questi o n should no longer be if x- ra y ana lysis can be

Subluxation

72

The

Artl~

lesion

>

Commonly Used Radiographic Lines, Angles, and Measurements

line, Angle , Measurement

Figure

Proposed Clinical Significance

Lumbar gravitational line Lumbar lordosis angle

5

Anrerior or posterior weight-bearing on lumbosacral disc

Lumbosacral base angle

7

Determines shearing or compressive forces on discs and facets Can be increased in facet syndrome

7

Can be increased in hyperlordosis

Lumbar Spine

Hyperlordosis or hypo lordosis determines stress on discs or facets

Lumbosacral disc angle Lumbar intervertebral disc angles

McNab's line Flexion-extension analysis Hadley's US" curve

Ullman's line Meyerding's grading Eisenstein's method Interpediculate distance Canal/body ratio

George's line

12

4

6

Unreliable method of assessing facet impingement or imbrication Measure of instability on lumbar flexion--extension views Method of assessing facet impingement or imbrication For assessing presence of LS-Sl anterolisthesis Method of grading spondylolisthesis (Grades 1-5) Lumbar sagittal canal diameter: stenosis or widening Lumbar co ronal canal diameter: stenosis or widening Combined sagittal and coronal canal diameter Disrupted in anterolisthesis or retrolisthesis

Cervical Spine and Skull Base

Chamberlain's line McGregor's line George's line Posterior cervical line

jackson's lines Angle of cervical lordosis Cervical gravity line

11 10

Cervical range of modon

Atlantodental imerval (ADI)

Basilar invagination, cranial settling, basilar impression Basilar invagination, cranial settling, basilar impression Cervical or lumbar, anterolisthesis or retrolisthesis Anterolisthesis or retrolisthesis or neural arch fracture Alterations in physiologic stress lines on flexion-extension views Hypolordosis or hyperlordosis measurement Anrerior or posterior weight-bearing Measurement performed on flexion-extension views Indicates atlantoaxial instability from transverse ligament

damage Sagittal canal diameter Pre vertebral soft tissue spaces

8 9

Stenosis or widening from intraspinal mass Inflammation, hemorrhage, or mass in soft tissues

used as a too l in th e sc ie nt ific in vest iga ti on o f c hi-

occ iput can be a ca usa tive facto r in the c hi roprac-

rop racti c subluxa ti o n. Ra ther, studies sho uld be designed, using x- ray a na lys is, to test rhe fund amenta l hypothesis of rhe ana lys is techniq ues, tha t

ric subluxa ti o n " (38) .

static stru ctu ra l [m is Jal ig nmenr in th e nec k an d

"systems" ta ug ht primaril y th ro ug h entrepreneur-

In his rev iew, Owens lists 15 named chiro-

practic rad iograph ic analys is tec hniques that a re

73

5 The Role of Radloraphy In Evalll8tmg SUbluxation ial postgraduate weekend seminars. Of the 15 techniq ues, onl y twO (Go nstead a nd upper cervica l specific-hole in one [HIO] ), are taught as parr of the curriculum at more than one accred-

ited chi ropractic college (38). Lo add ition to the many "systems approaches" to marking radiographs, severa l lines and angles of measurement have been developed in the fields of radiology and ch iropractic for assessing staric and functional radiographs (39,40). Table 5-1 ou tl ines some of the more common proce-

du res and rheir clinical significa nce, and rhe box below lists the classification fo r intersegmental subluxations that sometimes can be seen on static

>

Radiographic C lassification of Subluxation

SIIU.I.............I MIuIII.mI'"

• • • • • • • • •

Flexion malposition Extension malposition Lateral flexion malposition Rotational malposition Anterolisthesis Spondylolisthesis Retrolisthesis Lareralisrhesis Decreased interosseous spacing

• Foraminal encroachments

KlneU. InII....m.nIIlllylfuncll...

• Hypomobility • Hypermobility

and functional radiographs (Figure 5-3) (41 ). Figures 5-4 to 5-10 illustrate some of the more commonly used lines, angles, and measurements. It shou ld be emphasized, however, that the clinical significance of static misalignment subl uxations has never been clearly established. Many of the patterns listed in the box on this page actuall y only occur as a result of articu lar derangements

such as severe inflammatory or degenerative disc a nd apophysea l joint disease, o r long-stand ing developmental articu lar changes. One area of radiographic ana lysis rhar has received conside rable anemian is the cervical curve and its degree of lordotic configuration (Figure 5- l1 ). Over rhe years, chiropractors have attributed various degrees of sign ifica nce to the presence of hype rlo rdosis, hypolordosis, fl attened lordosis, and kyphosis . After his review of the literature on the curve of the cervical spine, Gay (43) conclu ded that there is a wide ra nge of normal, th at many traumatic and nonrraumaric fac-

tors influence the curve, and that there is little evidence-based support of the contention that altered cervical curva ture has any prognostic sig-

nificance (42). He fou nd, based on the literature, thar lo rdotic straighte ning or reversal could result from muscle spasm, but that more specific interprerarion is speculative. He emphasized that, altho ugh acute angu lar kyp hosis cou ld represent an unstable ligamentous injury sllch as is seen in hyperflexion sprains, it could represent a norma l variant in the absence of clinica l a nd further radio ographic corroboration (42).

• Aberrant motion

Secllo.. 1Sebluull...

• • • •

Scoliosis secondary ro muscle imbalance Scoliosis secondary to structural asymmetry Decompensation of adaptational curvatures Abnormalities of global motion

Pa....rt.bral S. bluull...

• Costovertebral • Costotransverse • Sacroiliac

Functional Radiography and Spinal Dysfunction Gi llet and Leikens (4) and Schafer and Faye (5) are responsible for raising chiropractic awareness of the importance of spine function and placing more emphasis on dynamic concepts such as fixa tion ana lysis and movement palpation. This paradigm sh ift, from a static ro a dynamic approach to spine analysis, initiated an increase in the lise Tex( cominued on p. 78

74

Rgare ~8 Static Intersegmental Misalignments. Top, Lateral flexion malposition. Bonam, Larerallisthesis. Although an extensive classification of static intersegmental misalignments exists (Table 5-3), it is unusual ro observe genuine malpositions on radiographs in the absence of seve re degene rative or inflammatory joint changes. Note in both Top and Bottom the advanced discovertebral and apophysea l degenerative changes a ll owing rhese non physiologic mal positions to occur. Most nondegenerarive or noninflammatory misalignments seen on radiographs actually represent asymmetry of vertebral structures.

flIIre 6-4

Lumbosacral Spondylolisrhesis. Myerding's method of measuring slippage in spondylolisthesis involves dividing the sacrum inro four equal quadrants on the lateral lumbosacral radiograph. The degree of slippage is graded based on the alignmenr of the posterior aspect of the L5 vertebral body with one of the quadranrs. The illustration above demonstrates a grade 2 spondy lolisthesis.

5 Tbe Hole 01 HMilography In Evaluating SUbUXallon

..... 5-5 Lumbar Gravitational Line. This line is constructed by identifying the central portion of the L3 vertebral body on a weight-bearing larerallumbar

radiograph. A vertical line is constructed inferiorly from this center paine. In the "ideal" weight-bearing pOSTure, this line should intersect the anterior portion of the sacrum. In anterior weight bea ring, the line falls anterior to the sacrum; in posterior weight bearing, frequendy associated with hypcrlordosis, the line falls posterior to the anterior portion of the sacrum.

75

Rgare H George's Line. George's line is drawn to detect evidence of anrerolisrhesis or retro lisrhesis. On a lateral rad iograph of either the lumbar o r cervica l spine, a conrinuous verrica ll ine is drawn along rhe posre rior margins of rhe verreb ra l bodies. In the norma l situation, this li ne shou ld be smooth, curvi linear, and uninterrupred.

FlgLre6-7 Lumbosacral base angle a nd lumbar interverteb ra l disc a ngles. Ferguson's angle or the lumbosacral base angle is obtai ned on the late ral lumba r radiograph by constructing a line along the

superior aspect of the sac ral base. The angle formed between th is line and an intersecting horizontal line is then measured (curved arrows). On upright radiographs, this measurement ranges from 26° (0 57°, An increase in this angle has been associated with an inc reased incidence of spondylo lytic spondylo li sthesis. In measuring the lumba r imerverrebral disc angles,

lines are constructed along the vertebra l end plates of the lumba r vertebrae. The intersecring angles indicate the configuration of the inrerve rreb ral disc (open arrows). The norma l range is 10° ro 15°. Excessive angulation is seen in hyperextension or hyperlordosis, and diminished angulation is seen in patients with hypolordosis or acu te flexion anta lgia.

FIIIn 6-8 Sagirral ca nal diameter: cervical spine. The sagitta l cana l di a meter is measured on a neutra l latera l cervical radiograph taken at 72-inch target-film distance. Measurements less than 12 mm suggest canal stenosis, and excessive measurementS (more than 22 to 3 1 mm ) suggest a space-occupying lesion expanding the sp ina l ca na l.

5 11HI Role 01 RadIography In Evaluating 8u1*1xallon

77

~

D

6

c::' c;:'J

~I

C'-

c:: Ag&re 5-9

a

/

Preverteb ra l soft tissue meas urements. The prevertebral soft tissues can be meas ured on a neutral lateral cervica l radiograph taken at 72-inch target- fi lm distance. The measurement at C2 sho uld not exceed 5 ro 6 mm and at C6 sho uld not exceed 20 mm. These measurements are wider in cases of rerrorrachea l, rerropharyngeal, o r rerrolaryngea l abscess, neoplasm, or posttraumatic hemaroma.

f9n 5-10

Ce rvica l sp ine ce nter of gravity. The cervica l gravity lin e is measured by constructing a vertica l line from the superio r tip of the odonto id process. Th is line sho uld intersect th e C7 vertebra l body. When the line passes anterior to the C7 body such as in the schematic diagram a bove, the patient is said to have anterior head ca rriage or anterior weight bearing.

78 Functional radiography typically is used to esta blish the presence of: 1. 2. 3. 4. 5. 6.

Segmental or global hypomobility or fixation Segmental or global hypermobility Segmental instability Aberrant segmental or global motion Paradoxical motion Postsurgical arthrodesis evaluation

Considerable disagreement persists regarding the indication for functional radiography. The chief concern revolves around the issue of radiation exposure (64-68). In all cases, the anticipated benefit of the study must outweigh the potential risk of ionizing radiation. Although some practitioners use functional radiography routinely, most aut horities agree that it should be reserved as a supplementary procedure. The following guidelines are suggested for the use of functional radiography based on clinical findings :

1. Persistent signs and sympcoms or unsatisfac-

A111'15-11 Cervical lordosis measurement. The cervical lordosis is measured by constructing lines along the atlas plane line and the inferior end plate of C7 on a neurcallateral radiograph. Perpendicular lines then are constructed and the intersecting angle is

measured. Although 30° ro 45° is generally considered "normal," a wider range of normal exists. Several factors, including muscle spasm, influence the degree of curve, but there appea rs to be no prognostic

significance of altered curvature.

of functional radiography in chiropractic. Many authors, both ch iropractic and nonchiropracric, have addressed the issue of functional radiography of the lumbar (43-5 1) and cervical (52-63) spine.

tory response to a conservative trial of chiropractic care 2. Suggested persistent segmental dysfunction 3. Suggested segmenta l instability 4. When other approp riate imaging studies are inconclusive in establishing joint dysfunction Meticulous attention to patient positioning is essential in functional radiography. Because of the difficu lty of precise, standardized positioning in each patient, quantitative measurements derived from these films are subject to inaccuracies (55). Therefore, functional radiographs should be used more as qualitative indicators of spine motion rather than as a precise quantitative assessment. Another significant limitation of functional radiography is that the range of "norma l" segmental motion in the genera l population has never been established. Wide variations of spina l motion exist in the normal population, and there is no evidence to confirm that too much or too little motion correlates with pain or disability, except in some cases of obvious instability (59) .

5 Tbe Role of RMilography iI Evaluatilg SUl*ixalloo

Lumbar Spine Functional radiographs of the lumbar spine include flexion-extension and latera l bending studies. Flexion-extension radiogra phs are used mOSt often to evaluate translational movements between segments. Excessive translational move-

ments indicate the possibility of instability and must be correlated with the clinical examination. Most authors agree that more than 3 to 5 mm translation from flexion to extension must raise

79

the possibility of ligamentous instability (Fig ure 5-12) (47,50) . Tanz (49) has identified the ave rage ranges of segmental lumbar flexion at various ages as indi-

cated in Table 5-2 . Tanz's study showed that segmental flexion increases at each successive level descending from L2-L3 through L5-S1 in the young healthy spine. With increasing age, motion decreases throughout the spine. With increasing age, motion decreases throughout the spine such that only minima l differences in segmental morio'n are observed at successive leve ls.

Flexion

Extension

Hgare 5-12 Flexion-extension analysis of the lum bar spine. Several methods have been developed to analyze functional radiographs of the lumbar spine for evidence of insrabilir)'. The schematic diagrams above illustrate tracings of the L4-S and LS-S I levels from flexion (A) and extension (BJ radiographs. Many aurhors comend that excessive translational movemems measuring above 3 (Q 5 mOl suggests ligamemous in scabi li r)',

80 Range of Lumbar Flexion at Various Ages' Age (ye ... ) 511-64

2- 13

35-49

10° 13° 17° 24°

5° 8° 9° 12° 8°

65-77

level

Ll-L2 L2-L3 L3-L4 L4-LS LS-SI

4° 5° 8° 8° 8°

2° 5° 3° 7° 7°

.. Adapted from Tanz 55. Motion of the lumbar spme. AJR 1953; 69,399.

Latera) bending radiographs have attracted significant interest within the chiropractic profes-

sion since the articles by Cassidy (43) and Grice (44) appeared in the 1970s. They recommended using lateral bending radiographs for several assessments, including:

l. 2. 3. 4.

Global range of motion Segmental body rotation Segmental disc wedging Aberrant lateral flexion analysis

They developed a method for studying lateral bending radiographs to evaluate the coupled lumbar motions of rotation and lateral flexion. They identified four types of segmental coupling motions and have attempted to correlate these aberrant patterns to various muscular imbalances

and joint dysfunctions (43,44). A more recent study by Hass and Cassidy and others questions the use of lateral bending radiographs for categorization of the lumbar spine in clinical practice (69) . It shou ld be emphasized that all radiographic findings must be correlated with clinical findings to be considered significant (Figure 5-13) . Table 5-3 lists the average ranges of segmental lumbar lateral flexion at various ages (49). The values indicate maximum lateral flexion occurring at the L3-L4 and L4-L5 levels with very min imal motion occurring at LS-Sl. Significant

reduction in lateral flexion occurs at all levels with increasing age.

Figll'85-13 Lateral Aexion analysis of the lumbar spine. Left lateral Aexion (A), Neutral AP (8), and right lateral nexion (C) radiographs of the lumbar spine in a 30-year-old man with acure low-back pain. The ana lysis of coup led Illotion on lateral flexion radiographs was advocated in the 1970s and 19805. Recent studies, however, suggest that these analyses are of little value in categorization of the lumbar spine in clinica l practice. Information from all radiographs must be correlated with clinical findings .

Cervical Spine Flexion and extenSion views of the cervical spine form an integral part of the cervical Davis

series. Coupled with routine views of the cervical spine, flexion-extension views can provide important information about the osseous and soft tis-

sues of the cervical spine (52,53,58). Coupled

81

5 TIle Role O'RadIography In Evaluating SUbluxation

"-" 5-13 continued

~

5-13 continued

motions of rotation and lateral flexion are difficult ro analyze in the lower cervical spine because

of the complexity of motions involved, and radiographic evaluation in these planes is nor recom -

mended.

)

Range of Lumbar Lateral Flexion at Various Ages

The flexion-extension examination is used

extensively in assessing the effects of trauma on the cervical spine (Figure 5-14, A-C). Excessive (mo re than 3 mm) translational segmental movements can signify instability. Atlantoaxial instability is recognized radiographically as an increase in the atlantodenta l interval measuring

more than 3 mOl in adults and 5 mm in children on the neutral lateral or flexion views (39) . Similarly, hypermobility, hypomobility, and aberra nt and paradoxical motion can be identified, according to some authors (52-54 ).

Ap. (y •• rs) 2-13

35-49

50-&4

65-77

12° 12° 16° 15° 7°

5°

5° 7°

4° 7° 6° 5° 0°

level

Ll-L2 L2-L3 L3- L4 L4-LS L5-S1

go go go

2°

go

7° 1°

Adapred from Tanz 55. Motion of the lumbar spine. AJR 1953; 69,399.

82

SUbluXation

The ArtIcular lesion

Agars 5-14 Cervical flexio n-extension o verl ay stud y. Extens ion (A), neu tral (8 ), and flex ion (e ) radiographs ca n be analyzed for inrersegmenral morion

by trac ing

the anato mi c ourl ines from the neutral radi ograph

(soUd line in D and E) and compa ring these with the extension (D ) and fl ex ion (E) trac in gs (do tted a"e in D and E), whic h are su perimposed on the neutral trac ings. This procedure is performed most frequently in patients after sp ine trauma and is used to detect excessive or abnorma l moti on.

Cervica l overlay studies are useful in idenrifying fl ex ion-extension moti on abnorm alities (5 1-

53). In this proced ure, o utlines of rhe ve rtebral bodies from the radiogra phs a re traced on acetate tra nspa rencies with colo red fi ne-tip pens. [n this way, a depic tio n of segmemal mo tio n can be com pared berween flexion, neutral, and extensio n positions (Figure 5- 14, D-E) .

83

•

/'

. .. •

c;::.

.. D .. ••

•• '

.........,.......

~

'

----D

E

Exte . N;~:~

fIIin fH40

........ ....

For legend see o pposite page.

J

Flexion ...................... . Neulrol - --

RIIN fi.14f For lege nd see OpposIte . page.

84 Another method of evaluating motion on cervical flexion-extension radiographs is to identify the instantaneous axis of rotation (lAR) at each vertebra l level. The LARs are then compared with well-established normal values (55-57). Although this method appears reliable and va lid, it has yet to gain widespread clinical use. Open-mouth views taken in lateral flexion can demonstrate excessive lateral translation of the arias lateral masses In relation to axis 10 atlantoaxial instability and abnormal motion in rotary atlantoaxial subluxation (61) .

ConclUSion The role of radiography in chiropractic is well established. Several clinical indications for radiography, based on patient history and physical finding;, have been identified. In addition to using radiographs for identifying pathologic processes, chiropractors often use both static and ,'ynamic radiographs to derive postural and biomechanical information. Many radiographic lines, angles, and measurements have been demonstrated to be reliable indicators of postural and biomechanical abnormalities. These indicators help identify static a nd dynamic subluxation , dysfunction, and abnormal or excessive motion. Further research is necessary, however, to determine the precise clinical significance of many of these procedures.

Acknowledgments Special thanks to Drs. R. Sherman and T. Bergmann for reviewing the manuscript for this chapter and offering many helpful suggestions.

References 1. Hildebrandt RW. Chiropractic spinography and posrural roentgenology. Part I. History of development. J Manipulative Physio] Thee 1980; 3:87-92. 2. Taylor JAM. Full -spine radiography: a review. J Manipulative Physiol Ther 1993; 16:460-74. 3. Sandoz R. Some reflections on subluxations and adjustmenrs. Annals of the Swiss Chir Assoc 1989; 7-29. 4. Gillet H, Leikens M. Belgian chiropractic research notes. 7th cd. Brussels, self-published. 1967. 5. Schafer RC, Faye LC. MOlion palpation and chiropractic technic: principles of dynamic chiropractic. Hunringron Beach. California: ACAP and MPI , 1989.

6. Sherman R. Chiropractic x-ray rationale. J Can Chiro As,oc 1986; 30,33-5. 7. Phillips R. Plain film radiology in chiropractic. J Manipulative Physio! Ther 1992; 15:47-50. 8. Howard BA, Rowe LJ. Spinal x-rays. In: Haldeman S, ed. Principles and practice of chiropractic. 2nd cd., East Norwalk, Connecticut: Appleton & Lange, 1992: 361-4. 9. Deyo RA, Diehl AK. Lumbar spine films m primary care: Currenr use and eHecrs of selective ordering criteria. J Gen Intern Med 1986; 1:20-25. 10. Herbst RW. Full spIRe radiography. In: Gonstead chiropractic science and healing art. Me Horeb, Wisconsin: Sci-Chi Publications, 1977; 145-56. 11 . Ganerman MI. Standards of practice relative to complications of and conrraindications to spIRal manipulative therapy. J Can Chir Assoc 1991; 35:232-6. 12. Wyatt LH, Schultz GO. The diagnostic efficacy of lumb:n spine radiography: a review of the literature. In: Hodgson M, cd. Currenr topics in chiropractic. Sunnyvale, Cali for nia: Palmer College of Chiropractic-West, 1987. 13. Howe JW. The role of x-ray findings In structural diagnosis. In: The research status of spinal manipulative therapy, Washington, O.c.: NINCDS Monograph No.1 S. US D11EW, 1975,239-47. 14. Sausser WL. New spinographic technique: the full length x-ray plate IS a success. The Chiropractic Journal 1933; 18-19. 15. Thompson EA. Chiropractic spinography. 2nd ed. Davenport, Iowa: Palmer School of Chiropractic 1919: 15-27. 16. Hildebrandt RW. Chiropractic spinography. 2nd cd. Baltimore: Williams & Wilkins 1985: 1-259. 17. Wintcmcin JF. Chiropractic splnographology. Lombard: National College of Chiropractic, 1970. 18. Plaugher G, Hendricks AH. The inter- and mtraexamincr reliability of the Gonstead pelvic marking system. J Manipulative Physiol Ther 1991; 14:503-8. 19. Logan HB.ln: Logan VF, cd. Textbook of Logan basic methods. St. Louis: Logan Chiropractic Cottege. 1950. 20. Van Schaik JPJ, Verbiest H, Van Schaik FDJ. Isolated spinous process deviation: a pitfall in the imerpretation of the lumbar spine. Spine 1989; 14:970. 21. Howe JW. Facts and faJlacies. myths and misconceptions in spinography. J Clin Chiro, Archives Edition II. 1972; 1-7. 22. Hildebrandt RW. Chiropractic spinography and posrural roenrgenology, II. Clinical basis. J Manipulative Physiol Thee 1981; 4,191-201. 23. Beekman CE, Hall V. Variability of scoliosis measuremenr from spinal roemgenograms. Phys Ther 1979; 59:764-5. 24. Ylikoski M, Tallroth K. Measurement variations in scoliotic angle, vertebral rotation, vertebral body height, a nd intervertebral disc space height. Spinal Dis 1990; 3,387-91. 25. Carman DL, Browne RH, Birch JG. Measurement of scoliosis and kyphosis radiographs: Imraobserver and Inlerobserver variation. J Bone Joint Surg 1990; 72A:328-33.

85 26. Mehta MH. Radiographic estimation of vertebral rOtation in scoliosis.J Bone Joim Surg 1973; 558:513-20. 27. DeSmet AA, GOIO JE. Asher MK, Scheuch HG. A clinical study of the differences between the scoliotic angles measured on posteroanterior and ameroposterior radio-

g

Goals of Manual Therapy

Manual Therapy is thought 10 pmdllCl! maltges i ..: • Joint alignment • Dysfunction of motion • Spinal curvature dynamics • Entrapment or extrapment of a synovial fold

(15)

Soft na.. EIII*

• Changes in the tone and strength of suppotting musculature • Influencing the dynamics of suppottive capsuloligamentous connective tissue (viscoelastic properties of collagen)

_"10111 EIIIcII • Reduction in pain • Altering motor and sensory function • Influencing autonomic nervous system regulation ...,.Ioglc EfII* • Laying on of hands • Placebo factor • Patient satisfaction

7 ctnpractlc RIIIIx TIIChnIqua is necessa ry to understand, however, that because a wide variety of methods exists, the assumpcion that all manual therapy, adjustments, or manipu -

lations are equivalent must be avoided (4). Factors that influence the selection of manual procedures (5) include: I. 2. 3. 4. 5.

Age of the patient Acuteness or chronicity of the problem General physical condition of the patient Clinician's size and ability Effectiveness of previous or current therapy

Manual procedures can be specifically directed to the soft tissues. Even though all manual

107

Mechanica l devices have been used with manua l therapy to provide light force contacts and to produce purportedly controlled, repeatable percussion forces. Although some evidence exists to support that these procedures move joints, there is seldom an audible release or cavitation response (8). A factor that seems to be common to the body-wall reflex technique procedures is that the irritable "lesion" resides in fascial tissue. Therefore it is necessary to explore the structure and function of connective rissue, because it is a sig-

nificant component of the fascia as well as of all the soft tissues.

techniques have some effect on the soft tissues,

Connective tissue contributes to kinetic joint

the justification for a separate classification is to

stability and integrity by resisting the rotatory moments of force developed by forces acting at each joint. When these rotatory moments of force

draw attention to the prime importance of includ-

ing techniques that have the specific purpose of improving the vascularity and extensibility of the soft tissues (6) as well as to reflexively influence neurologic elements and physiologic processes. Furthermore, soft tissue manipulation tends to

relax hypertonic muscles so that, when other forms of manual therapy are applied, equal tensions are exerted across the joint. Soft tissue manipulation includes massage (stroking or effleurage, kneading or petrissage, vibration or tapotement, transverse friction massage), trigger point therapy, connective tissue

massage, body wall reflex techniques (Chapman lymphatic reflexes, Bennert vascular reflexes, acu-

are large, considerable connective tissue power is

required to produce the needed joint stability and integrity. Within the past several decades a great deal of scientific investigation has been directed at defining the physical properties of connective tissue. Connective tissue is made up of various densities

and spacia l arrangements of collagen fibers embedded in a protein-polysaccharide matrix, which is commonly called ground substance. Collagen is a fibrous protein that has a very high tensile strength . Collagenous tissue is organized into many different higher-order structures, including

pressure point stimulation), and muscle energy

tendons, ligaments, joint capsu les, aponeuroses,

techniques. [n addition, some methods of chiropractic adjustment apparently have a greater direct affect on the soft tissues or have a greater effect on the homeostasis of the body through

and fascial sheaths. Therefore, under normal and pathologic conditions, the range of motion in most body joints is predominately limited by one

reflex mechanisms.

or more connective tissue structures. The relative contribution of each to the total resistance varies

Meeker (7) identifies chiropractic soft tissue techniques as those physical methods applied to

with the specific area of the body.

muscles, ligaments, tendons, fascia, and other

involved in the body's reparative process frequently impedes function because it may abnormally limit the joint range of motion. Scar tissue,

connective tissues with the goal of therapeutica ll y affecting the body. He also defines non force techniques as very light force methods sometimes applied to the soft tissues but most often to the bony parts of the spine and pelvis with the goal of improving the hea lth of the patient.

After trauma or surgery, the connective tissue

adhesions, and fibrotic cont ractures are common

types of pathologic connective tissue that must be dealt with during chiropractic manipulative procedures. Understanding the physica l factors influ-

108 cocing mechanical behavior of connective tissue under tensile stress is therefore essential for deter-

mining the optimal means through manipulation to restore normal function.

All connective tissue has a combination of two qualities, elastic stretch and plastic (viscous) stretch. The term stretch refers to elongation of a linear deformation that increases in length. Stretching, then, is the process of elongation . Elastic stretch represents springlike behavior. Elongation produced by tensile loading is recovered after the load is removed. It is therefore also described as temporary or recoverable elongation. Plastic (viscous) stretch refers to puttylike behavior, in which the linear deformation produced by tensile

tress remains even after the stress is

removed. This i described as nonrecoverable or as a permanent elongation. The term viscoelastic

is used to describe tissue that represents both viscous and elasric properries (9). There are different factors that influence whether the plastic or elastic component of connective tissue is predominately affected. These include the amount of applied force and the duration of the applied force. Therefore the major facrors effecting connective tissue deformation are

force and time. A high force over a short period results in elastic deformation . A lower amount of force sustained over a longer period produces plastic deformation. When connective tissue is stretched, the rela-

Trauma generally occurs as a result of a high force of shorr duration that influences the elastic deformation of the connective tissue. If the force is beyond the plastic range of the connecrive tissue, it enters the plastic range. If the force is beyond the plastic range, tissue rupture occurs. Commonly encountered is the microtrauma seen

in postural distortions, muscle imbalance, and joint dysfunction as a result of low gravitational forces occurring over a long period, thus creating

plastic deformation.

Enects 01 Immobilization Connective tissue elements lose their extensibiliry when their related joints are immobilized (10). With immobilization, water is released from the proteoglycan molecule, allowing connective tissue fibers

[Q

contact one another, encouraging abnor-

mal cross-linking and resulting in a loss of extensibil ity (11). It is hypothesized that manual therapy can break the cross-linking and any intraarticular capsular fiber fatty adhesions, thereby providing free motion and allowing water inhibition to occur. Furthermore, procedures can stretch

segmental muscles, stimu lating spindle reflexes that may decrease the state of hypertoniciry ( 12). Muscle tightness or shortness develops after periods of immobilization as well. Length changes in muscle are associated with changes in sarcomere number, and reorganization of the con-

tive proportion of elastic and plastic deformation can vary widely, depending on how and under what conditions the stretching is performed . When tensile forces are continuously applied to

nective tissue elements within the muscle (13). Muscle immobilized in a shortened position develops less force and tears at a shorter length

connective tissue, the time required to stretch the tissue a specific amount varies inversely with rhe

ing length ( 14 ). For this reason vigorous muscle stretching has been recommended for mu c1e tightness (15). For the stretch to be effective, however, the underlying joints should be freely mobile. Patients often tequire manipulation before muscle stretching. Cantu and Grodin (16) reviewed the literature on the effects of manual therapy on fascia, which include circulatory changes, blood flow changes,

forced used . Therefore, a low-force stretch ing method requires more time to produce the same amount of elongation as that produced by a higher-force method. However, the proportion of tissue lengthening that remains after the tensile stress is removed is greater for the low-force,

long-duration method. Of course, high force and long duration also cause stretch and possibly rupture of the connective tissue.

than nonimmobilized muscle with a normal rest-

cap illary

dilatation,

cutaneous

temperature

changes, metabolic changes, and reflexive auto-

7 Chi'opractIc Rallex TecI1nIquea nomic changes. However, most of the citations were quite old .

Enects on Blood How InI Temperature Deep stroking and kneading of the soft tissues in the extremities of normal subjects, patients with rheumatoid arthritis, and subjects with spasmatic paralysis create a consistent and clinically significant increase in total blood flow and cutaneous temperature (17). These findings are supported by other studies (18-20); however, it must be emphasized that the clinical procedure being tested in all of these reports was a deep or heavy massage application. Therefore, conclusions on the effects of light-force stimulation of the body wall cannOt be drawn from these data.

Enects on MetaboHsm Cuthbertson (21) performed a literature review on the effects of massage on metabolic processes, including vital signs and waste products of the body. He reported that, in normal subjects, there was no increase in basal consumption of oxygen, pulse rate, or blood pressure, although an increase in urine output was observed . To effect a change in the vital signs, however, a systemic affect must be achieved. Localized changes in basal consumption may occur but this has yet to be studied. Schneider and Havens (22) did find an increase in red blood cells needed to bring oxygen to the tissues being influenced with massage. This provides some suppOrt, then, for soft tissue procedures being able to increase circulation and nutrition to desired areas. Again, these were vigorous massage procedures that were described; caution is necessary when trying to apply these principles to other procedures.

109

may be activared rhrough connecrions with the lareral horn cells in the cord to produce vasomotOr, trophic, visceral, or metabolic changes. The impulse-based paradigm of neurodysfunction that has been developed from the work of Homewood (23) and Korr (24), suggests that somatic dysfunction or joint dysfunction induce persistent nociceptive and altered proprioceptive input. This persistent afferent input triggers a segmental cord response, which in turn induces the development of pathologic somatosomatic or somatovisceral reflexes (25-27). If these reflexes persist, they are hypothesized to induce altered function in segmentally supplied somatic or visceral structures. Manual therapy, including soft tissue techniques and other forms of adjustive therapy, would have the hypothetical potential for arresting both the local and distant somatic and visceral effects by terminating the a ltered neurogenic reflexes that are associated with somatidjoint dysfunction. Reflex pathways exist such that when a stimulus (see box below) is applied to a somatic structure of the body, a resulting response occurs in another somatic structure of the body. These are referred to as somatosomatic reflexes. Although they are considered the mOSt primitive reflexes in the human body, somatosomatic reflexes are essential to the control of normal physiologic activities and may become involved in abnorma l reactions. The somatosomatic reflex has a direct application to the problem of muscle alterations in the paravertebral region. When conditions are such that the stimulus elicits and abnormally prolongs a muscle contraction in this area, the tissues become a secondary source of irritation with the

>

Stimuli for Evoking a Somatosomatic Reflex Response

Renexive (Autonomic) EHects Reflexive or autonomic effects relate to evidence

• Variation in temperature

of change in tissues or structures distal to or distant from the site of therapeutic application. Lesions in the soft tissue can initiate sensory irritation, which produces referred pain and tenderness. Moreover, aumnomic nervous involvement

• Mechanical stress

• Chemical irritation • Environmental stress • Structural stress

110 potentia l of disturbing bomeostatic balance. If the

Somatoautonomlc Renax Theory

individual's inherent resistance cannot compen-

Korr (24) proposed that spinal muscles, when

sate for the imbalance, clinically recognizable symproms may result (28). One of the signs of somatic dysfunction is the presence of muscle hypertonicity. Localized increased paraspinal muscle [One can be detected with palpation and in some cases with electromyography. Janda recognizes five different types of increased muscle rone: limbic dysfunc-

under strain or tension, caused the firing of pro-

tion, segmental spasm,

reflex spasm, trigger

points, and muscle tightness (15). Liebenson has discussed the treatment of these five types using active muscle contraction and relaxation procedures (29).

I1811ex Muscle Spasm from SplnallI$I'y Reflex muscle spasm or splinting follows trauma or injury ro any of the pain-sensitive structures of the spine. The pain-sensitive spinal tissues include the zygapophyseal joints, posterior ligaments, paravertebral musc.les, dura mater, the anterior and posterior longitudinal ligaments, and the intervenebral discs (30). Mechanical deformation o r chemical irritation of any of these tissues

causes restricted motion by way of muscle spasm. Treatment directed at the rissue source of pain

reduces the reflex muscle spasm and increases the range of motion; however, if the muscle spasm has been present for some time it requires direct treatment as well.

Renax Muscle Spasm from VllCerIi Dlseasa Visceral disease also can cause reflex muscle splinting. T he diagnosis of a viscerosomatic reflex is based on a history of visceral disease, or current visceral disease sympromarology, and objective palpation findings (31). Objective palpation findings include: twO or more adjacent spinal segments that show evidence of fixarion located within a specific auconomic reflex area; a deep

prioceptive nerve receptors embedded in the muscles. Korr believed that this proprioceptive information, which synapses with second-order neu-

rons located in the spinal cord, facilitated or lowered the firing threshold of the second-order neurons. When second-order neurons are facili-

tated, they act as a "neurologic lens" and are hyperresponsive to impulses reaching them from any source in the body. He termed this hyperirritability chrollic segmelltal {acilitatioll (24) . Second-order neurons synapse with a variety of cell in the nervous system; however, Karr focused primarily on the local segmental connections in the spina l cord. In the spinal cord, second-order neurons synapse with amerior horn ceils, which innervate muscle, and with latera l horn cells, which are pan of the sympathetic nervous system. Karr proposed that continuous irritation of the lateral horn cells caused these (sympathetic) neurons ro become faci litated. A facili tated or hyperirritable sympathetic nervous system is considered by Korr to be a major contributing factOr in perpetuating musculoskeletal dysfunction and visceral organ exhaustion and disease (24) . Numerous conditions have been linked to hyperactivity of the sympathetic nervous system, including various rypes of cardiovascular, gastrointestinal, and genitourinary disorders, and certain musculoskeletal disorders such as reflex sympathetic dystrophy.

Evidence or Chronic SBtIIIIBIdII Faclltallon Korr and his osteopath ic colleagues performed several elaborate srudies that supported his theory of chronic segmemal facilitation (32). The presence of segmental muscle spasm at the site of spinal dysfunction supported the reflex connection to the anterior horn cells. The presence of

[Q

vasomotor changes (vasoconstriction or di lata-

segmenta l joint motion; and skin and subcutaneous tissue changes that are consistent with the acureness or chronicity of the reflex (3 1).

rion), sudomoror changes (sweating or dryness), and pilomotOr changes (hair follicle elevation) at the site of spina l dysfunction supported the reflex

paraspinal muscle splinting reaction; resistance

7 CIIII"IIPI'aclic Rellex TIICbnIquea connection (0 the sympathetic nervous system. Korr proposed that, because hyperactivity was demonstrated in the sympathetic fibers innervat109 the skin, the sympathetic fibers innervating the viscera would also be hyperactive and possibly contribute to visceral disease. The clinical evidence supporting this theory is primarily indirecr and based on rhe correlation of physical symptOms with spinal lesions. Because the spinal soft tissues are loaded with receptOrs, it seems plausible that any acute injury would resu lt in increased sensory input to the spinal cord, which in turn could result in segmental faci li tation .

The segmental facilitation theory is also called the Impulse-based theory because ir depends on impulses from the proprioceptive nerve receptors located in rhe spinal muscles. Nerve compression is nor a factor in this theory; in fact, facilitated nerves are functioning as they are designed: to carry information. Facilitated nerves become sensitized by the vast amount of stimulation they receive from strained muscles. Korr also postulated that when facilitated nerves become overburdened with activiry, their axoplasmic flow rate may become reduced. However, the primary lesion stressed in the segmental facilitation theory is sympathetic nervous system hyperactivity.

NocIceptors Reflexlvety Activate Sympathetic

NeII'ona Recent advances in the understanding of muscle spindle physiology question the ability of muscle spindles to activate sympathetic fibers (32). In response to this discrepancy in Korr's theory, Van Buskirk has ptoposed that nociceptors are the primary receptOrs causing chronic segmental facilitation and sustained sympatheticotOnia (32). SatO has recently reviewed the experimental studies of somatOvisceral reflexes (33). He and his colleagues have been able to alrer the heart rare, blood pressure, and renal and adrenal sympathetic nerve activity by applying mechanical pressure to the rat spine (34). In addition, it has been

111

discovered that stimulation of periarticular nociceprors causes a significant reflex activation of sympathetic neurons, whereas, in contrast, stimulation of nonnociceptive receptors has a minimal

influence on sympathetic activity (35). Unfortunately, the stimulation threshold required to cause nociceptor activity and subsequent symparhetic facilitation in the living human is unknown. In addition, the extent [Q which spinal dysfunction in patients mimics experimental animal lesions is unknown. Korr has recendy discussed some of the limitations of the segmental facilitation theory and points out the need for clinical outcome research that tests manipulative therapy as it is practiced (36).

Musculoskeletal Dysfunction and Visceral Disease Whether musculoskeletal dysfunction causes visceral disease appears ro depend on many facrors, such as the amount of nociceptive input from the musculoskeletal tissues, the previous threshold of the sympathetic neurons, in part determined by the central nervous system's ability ro reduce (or enhance) sympathetic activity, and the previous condition of the viscera. For this reason, musculoskeletal dysfunction is considered to be one of many potentiating factors that can lead to visceral dysfunction and disease. It is rhought that altered or impaired function of components of the musculoskeletal system either may cause or may be presympromatic signs of disease. There is, however, little more than anecdote or personal opinion ro support these ideas. Basic science information does exist to supPOrt the occurrence of somatovisceral and viscerosomatic reflexes (24-27, 31). This informarion does not, however, support a clinical utility for intervention. Although theory and clinical practice suggest that events affecting the musculoskeletal structures may influence visceral function and that disturbances of visceral function may be reflected as altered musculoskeletal func-

112 tion, the chiropractic profession has done nothing to adequately show the relationship between manipulative therapy and visceral disease. The hypothesis is, of course, that the musculoskeletal component may be treated with chiropractic procedures (adju tments and other modalities), altering the course of both the musculoskeletal and visceral disturbances, thereby allowing the physiologic process to return to optimal function .

Musculoskeletal ManHestations of VIsceral

DIsease

It has been suggested that the body wall manifestations of visceral disease are an integral part of the disease process, rather than just physical signs and symptoms (37). However, the definitive causative factors and the characrerisric response of the individual are still unknown. Early signs of most disease stares are manifested as symptoms and signs that are part of a common reaction pattern to injury or streSs. Pain in the somatic tissues is a frequent presenting symptom in acute conditions related to visceral dysfunction. PalpatOry cues of transient muscle hyperroniciry

and

irritation

or

subcutaneous

edema may be accompaniments of ill-defined subclinical states (31) . Moreover, subtle changes in tissue texture, joint position, and joint mobility identified by discerning palpatory ski lls appear to be latent manifestations of the somatic component of visceral disease (see box) . In a study (38) petformed on cardiac patients in an intensive carc unit, the following was noted

in the 3uronomic spinal reference site for the

involved viscus: Vasomotor reaction: increase in skin temperature Sudomotor reaction: increase in skin moisture Increase in muscle rone/contraction Skin texture changes: thickening Increased subcutaneous fluid In studies by Kelso (39) and Beal (40), it was noted that, as the visceral condition progresses, the omatic Stress pattern subsides, and the rypical visceral reflex pattern is seen. Therefore, the

>

Abnorma l Pa lpa to r y Findings Associa ted w ith the Application of Soft Tissue M a n ipula tion (7)

• Tenderness • Indurations

• Edema • Skin texture changes • Skin temperature chang•• • Muscl. hypertonicity • Joint hypermobility or hypomobility

chronic phase of reflex activity is characterized by trophic changes in the skin and subcutaneous ti sues, as well as by local muscle contraction. This typically results in a joint misalignment and decreased segmental mobility. It is not known, however, whether the continuation of reflex somatic dysfunction is related to the initial impact of the visceral disease, or whether it is a result of long-term segmental facilitation. In a blind study of 25 patients, Bea l (40) was able to differentiate patients with cardiac disease from those with gastrointestinal disease, with a reported accuracy of 76 0/0, using a compression test to examine for soft tissue texture changes and resistance to segmenta l motion. Similarly, Beal and Dvorak examined 50 patients in a physicianblind format and were able to identify characteristics specific for patients with cardiovascular, pulmonary, gastrointestinal, or musculo keletal diseases (41). The use of spinal manual therapy in the treatment of visceral conditions has been advocated on the hypothetical basis that ir is designed to reduce somatic dysfunction, to interrupt the viscerosomatic reflex arc, and ro influence the viscus through stimu lation of the somatoviscera l reflex. However, the effectiveness of manipulative procedures for the muscu loskeletal manifestations of organic disease has not been clearly established. There is a definite need for further data on the incidence of viscerosomatic reflexes and the relationship to manipulative therapy.

113

1 ChIroprIlC1lc l\ellex T~

Manual T1Ierapy and Somatoautonomlc

Renexes Manual therapies, and specifically chiropractic adjustments, are thought to disrupt harmful somatoautonomic reflexes by reducing the noxious input into the spinal cord. For example, a panell[

with

UC and nonfon;e tt'r.:hniqllell. In: 1-I.lklcman S. ed. Principle:, ilnd Jlraltice of lhlropral.:llc. Easl t'nrw.1Ik. Connenil.:lIt: AppletOn and l.ange. 1992:

120. 8. Osterhauer PJ. Fuhr A\'(I. The current .!.I.nus of acnV.lIor methodl> chlropraltic [C\:hnique. thear)" Jno tr:ul1Ing.

ChoroTech 1991,3( 11,19-2.1. 9. Bergmann TF, I}eu:rson OH, Lawrence DJ. ChiropractK Technique. New York: Churchill LIVingstone, 1993:34-5. 10. Akeson WH, Amlel D, Woo SLY. Cartilage and ligament: physiology and repair processes. In: Nicholas JA, Hershman EB, eds. The lower extn:nury and Splnt' In sports medldnc. St. LoUIS! Mosby, 1986:3-41. II. Akeson \VH. Amici 0, Mechanic Gl., \'(.'00 S. Harwood Fl. Hamer ML. Collagen cross linking alleranons In jOint Conrr:lCfures: changt."S in reducible cross Imks 10 perianicular connective tissue colJ:tgen 'lfter 9 weeks of Immobl117a[ioll. Connl'C[ Tissue Res J 977; 5:5. 12. Burger AA. [xperllnenral neuromu')(.:ular model~ uf spmal manual techniques. Manual ~Ied 1983; 1: 10. 13. Garren W, TIdball J. Myotendtnous juncrion: structure, funcrion, .lnd failure. In: Woo SI Y. BUlkwalrcr JA. cds. Inlury ano repair of the musculoskeletal soft rissues. Park Ridge, Illinois: Americ,1O Academy of OrthopaedIC Sur-

geon,. ,988,,99-200. 14. Jones yr. Garrell WE, '>caber AV. Biomcchanicallhanges in mu~le after immobllilatlon

J. Bcr1:tmann TE

ennal dlagnow;. ~l;lIlu.J1 Med 1991; 6: 136-9. M)·ofa~dal nl.1mpulatton theor)" and dinu:al application. Galthl'f\hurg, M.Jryi.lnd: Aspen.

1992;.1.1 -". 17. Wakim K(i. The "ftelrs of ma~sagt' on the I.:trI.:uiatinn In normal and paralp.ed extremities. Arch Phys ~Ied 1949;

30,13.1.

ClUff) Ttxh 1993; .5{lJ:5J-J.5.

4. Haldeman S. Spm::" manipulative therap), .1nd SPOrtS mcd· iUlIe. elm Sport.. .\It·d 1986; .5{lJ:2-:-7-29J. S. Cireenman P. PfIIKlpal ... of manual medlr.:me. Baltimore: William!> & Wilkins, 1989.

Physiol 1021, 6U28--47. (,M, Roth (.!\1. er al. Cutaneous remperarure ot

~1artln

the extrell1uiel> of norm.1i l>uh]e4.:tl> .lIld pallents with rheumatcud arthritIS. Arch Php Mcd Rehahd 1946: 2":"":66., . 21. CuthOertSon DP. Effect of massage on metJh()li~m: a ~ur­

J

~Icd 1931,2,200-13. ~hnelder lC. Havcns Changes m the wntems of

vey. GIa'gow

22. V~n()us form" of r.:hiropranlr.: (C(:hmque.

different lengths. Trans

16. C:tntu RI, Grodin AJ.

ltation 111 rhe ncrvous system. ACA J Chim 1973; 7(S):

17-25.

:It

Orthop Res Soc 1985; 10,6. IS. Janda V. MuS(.·le spasm: A propo'>Cd procedure for differ-

loc.

haemoglohln and rcd corpuscles in the hlood of men .It high a/tirudes. Ant J Pllr~lol 191J; 36:360. 23. Homewood AE. Neurod}'namit cervical spine. JCan Chlro Assoc 1989; 33: 177-183. 6. Henderson OJ, Dormon TM. Functional roemgenomcrric evaluation of the cervical spme m the sagittal plane. J Manipulative Physiol Ther 1985; 8:2 t 9-27. 7. Garrerman MI. Indications for spinal manipulation in the treatmem of back pain. ACA JChiro 1982; 16:51-66.

145 8. Cassidy JD, Poner CE. Motion examination of the lumbar spine. J Manipulative Physiol Ther 1979; 2: 151-8. 9. Lewit K. Malllpuiation: reflex therapy and/or restitution of impaired locomotor function. Manual Medicine 1986; 2,99-100. 10. McGregor M. Mlor S. Anatomical and functional perspectives of the cervical spme. Part III . The "unstable" cervica l spine. J Can Chiro Assoc 1990; 34:145- 152. I 1. Henling D. Kessler RM. Managemcm of common musculoskeletal disorders: Physical therapy principles and methods. 2nd ed. Philadelphia: J8 lippincott. 1990:522-23, 556-9. 12. Dvorak J, Froehlich D. Penning l, Baumgartner H, PanJab. MM. Functional radiographic diagnosis of the cervical spine: flexion/extension. Spine 1988; 13:748-55. 13. Dvorak J. Panjabi MM, Grob D, Novotny JE, Antinnes JA. Clinical validation of fu nctional flexion/extension radiographs of the cervica l spine. Spine 1993; 18: 120--7. 14. Lind B, Sihlbom H, Nordwall A, Malchau H. Normal range of motion of the cervical spine. Arch Phys Med Rehabi! 1989; 70,692-5. 15. Hviid H: Functional radiography of the cervical spine. Ann Swiss Chiro Assoc 1965; 3:37-65. 16. McGregor M, Mior S. Anatomical and functional perspectives of the cervical spine. Part I. The "normal" cervical spine. J Can Chlro Assoc 1989; 33:123-9. 17. Amebo B. Wonh D, Bogduk N.lnsrantaneous axis of rotation of the typical cervical motion segments. II. Optimization of technical errors. Clin Biomech 6:38-46, 1991. 18. Whue AA, Johnson RM, Panjabi MM, Southwick WOo Biomechanical analysis of clinical stabi li ty in the cervical spine. CIIn Onhop Rei Res 1975; 109:85-96. 19. Gehweiler JA, Osborne RL, Becker RF. The radiology of vertebral trauma. Philadelphia: WB Saunders, 1980,99-100,215-7,229,236,267,273. 20. Yochum TR, Rowe LJ. Essentials of skeleta l radiology. Vols I and 2. Baltimore: Williams & Wilkins. 1987:100, 103-5,176,244-5,269,431,434. 2 I. Reich C, Dvorak J. The functional evaluation of craniocervical ligaments In sidebcndmg USing x-rays. Manual Medicine 1986; 2,108-13. 22. Chapman S, Naklelny R. Aids to radiological differential diagnosis. London: 8ailliere linda II , 1984:53. 23. Resnick 0, Niwayama G. Diagnosis of bone and joint disorders. Vol 2. Philadelphia: WB Saunders, 1981: 1370-82. 24. Mick T, Phillips RB, Breen A. Spinal imaging and spinal biomechanics. In: Haldeman S, ed. Principles and practice of chiropractic. 2nd ed. East Norwalk, Connecticut: Appleton and Lange, 1992:402-12.

25. Dupuis PR, Yong-Hing K, Cassidy JD, Kirkaldy-Willis WHo Radiological diagnosis of degenerative lumbar spinal instabiliry. Spine 1985; 10:262-76. 26. Grieve GP. lumbar instabiliry. Physiotherapy 1982; 68,2-9. 27. Paris SV. Physical signs of instabiliry. Spine 1985; 10,277-9. 28. Frymoyer JW, Selby OK. Segmental instabiliry: rationa le fo r treatment. Spine 1985; 10:28G-6. 29. Frymoyer JW, Newberg A, Pope MH, Wilder DG, Clements J, MacPherson B. Spine radiographs in patients with low-back pain. J Bone Joint Surg 1984; 66A, 1048-55. 30. Hanley EN, Matteri RE, Frymoyer JW. Accurate roentgenographic deternunation of lumbar flexion-extension. Clin Orthop 1976; 115,145-8. 3 I. Dvorak J, Panjabi MM, Chang DG, Theiler R, Gross D. Functional radiographic diagnosis of the lumbar spine: Flexion-extension and lateral bending. Spine 1991; 16,562-71. 32. Hayes MA, Howard TC, Gruel CR, Kopea JA. Roentgenographic evaluation of lumbar spine flexion-extension in asymptomatic mdividuals. Spine 1989; 14:327-31. 33. Pearcy M, Ponek I, Shapherd J. The effect of low·back pain on lumbar spinal movements measured by threedimensional x-ray analysis. Spine 1985; 10:150--3. 34. Sandoz R. Technique and Interpretation of functional radiography of the lumbar spine. Ann Swiss Chiro Assoc 1965; 3,66-110. 35. Sha len PRo Radiological techniques for diagnosis of lum· bar disc degeneration. Spine: State of the Art Reviews; 3 ( 1),27-48. 36. Haas M, Nyiendo J, Peterson C, et a!. Lumbar motion trends and correlation with low back pain. Pan 1. A roentgenological evaluation of coupled lumbar motion in lateral bending. J Mampulative Physiol Ther 1992; 15,145-58. 37. Haas M. Nyiendo J, Peterson C, et al. Inter-rater reliabiliry of roentgenological eva luation of the lumbar spine in lateral bending. J Manipulative Physiol Ther 1990; 13,179-89. 38. Weitz EM. The lateral bending sign. Spine 1981; 6,388-97. 39. Magera A, Schwam A. Relation berween the low·back pain syndrome and x-ray findings. J. Degenerative osteoarthritis. Scand J Rehabil Med 1976; 8:115-25. 40. Catterman Ml. Chiropractic management of spine related disorders. Baltimore; Williams & Wilkins, 1990:170--1. 41. Muehlemann D, Zahnd F. Die lumbale segmentale hypermobilitaet. Manuelle Mediz.in (Ger) 1993; 31:47-54.

The S

T

xation Complex

he subluxation complex is a theoretical model of morion segment dysfunction (subluxation) that incorporates the complex interactions of pathologic changes in nerve, muscle, ligamentous, vascular, and connective tissues. First described by Faye as a paradigm shift from the static misalignment or "bone out of place" concept of subluxation, the vertebral subluxation complex has served as a more dynamic and inclusive teaching and research model for the chiropractic profession. According to Kuhn, a paradigm prepares students for membership in the scientific community with which they will later practice. By joining a group who learned the bases of their field from the same model, subsequent practice provides a basis for agreement over fundamentals. An accepted paradigm mUSt seem better than alternatives but does not necessarily explain all the facts with which it can be confronted . It suggests which experiments are worth performing and selects phenomena in more detail for more rigorous study. Supporting Palmer's concept that the neurologic component of the subluxation is the cornerstone of chiropractic theoty, the subluxation complex provides a structure for better understanding the foundation

148

11Ie Subluxation Complex

principles of chiropractic theory and provides a paradigm for chiropractic education and research.

Chapter 8 The Vertebral

Subluxation Complex presents an overview of the subluxation complex paradigm, outlining the ateas affected by the

articular subluxation. The interaction of the

pathologic changes of the nerve, muscle, ligamentous, vascular, and connective tissue components

is discussed. Taking the subluxation concept beyond that of a biomechanical lesion, this chapter explores the functional manifestations associated with the articular lesion.

Chapter 10

The Theoretical Causes of Subluxa-

tion discusses the proposed causative agents put

luxation on rhe nervous system. Used to visualize

the abstract principles involved, models of intervertebral encroachment, altered somatic afferent

input, and dentate ligament and cord distortion are discussed. These theories present the neurologic foundations of chiropractic theory in light of current supporting evidence.

Chapter 13

Vertebral Subluxation and the Anatomic Relationships of the Autonomic Nervous System emphasizes the impottant associa-

tion of the autonomic nervous system with the

effects of the subluxation complex. The potential for widespread changes in the parasympathetic and sympathetic nervous systems caused by vertebral subluxation is a controversial topic fundamental to the foundations of chiropractic princi-

forth to explain the misalignment, aberrant

ples. The anatomic relationships relative to this

movement, and dysfunction characteristic of the

debate are documented, with the physiologic implications for somatic dysfunction outlined.

subluxation. Articular adhesions, ligamentous shortening, meniscoid entrapment and extrap-

roeor, muscle spasm, and mechanical . Iocking have all been implicated as causative agents of the subluxation. The rationale and supporting evidence for these suggested causes are presented.

Chapter 11

Chapter 14

The neuroimmunologic implica-

tions of spinal manipulation are presented in

Chapter 14. Observed changes in the immune system after manipulation support the theory that improved neurologic function has beneficial effects on overall health. The possible role of

The Kinesiopathology of the Vertebral Subluxation emphasizes the aberrant movement component of the subluxation. Considered the primary element in the hierarchy of the subluxation complex, the kinesiopathology that both

Chapter 15

causes and results from altered movement in the spinal motion segment is examined. Both normal

dence that convergent input onto spinal neurons

and abnormal motion are considered, and the role the muscle spindle plays in each is presented .

Chapter 12

The Neurophysiologic Theories of the Chiropractic Subluxation reviews three theories that explain the proposed effects of the sub-

manipulation in modulating neuroimmunologic function is discussed.

Spinal Cord Plasticity and Mechanisms of Referred Pain explores the scientific evi-

produces widespread neurologic activiry. Studies evaluating the nociceptive "traffic flow" involved in spinal pain are discussed. Theories of somatosensory input with neuronal responses to

mechanical and sympathetic stimuli produced by manipulation are proposed.

J

The Vertebral Subluxation Complex Charles A. Lantz

Key Words

Vertebral subluxation complex, immobilization degeneration, dorsal root ganglia

After reading this chapter you should be able to answer the fo llowing questions:

QuestIOn #1

Of what benefit to the chiropractic profession is the vertebral subluxation complex?

QueatIon#2

How does minimal acute compression affect the dorsal root ganglion?

QuestIon#3

What effect does immobilization have on a spinal joint?

150

T

he Vertebral subluxation complex (VSC) is a model of spinal dysfunction from a chiropractic clinical perspective. In this model we describe the common and essential elements of spinal degeneration and dysfunction in an attempt ro make them more understandable in the context of chiropractic adjustive procedures. Classically, subluxations have been viewed as osseous impingement on nerves that interfered

with the proper functioning of those nerves. Hisrocically, this "bone on nerve " concept was seen ro be in direct conflict with the original osteopathic model of "muscle on vessel" shutting off the vital life-sustaining blood supply to the tissues. Current concepts have taken us beyond these limiting views, and we have grown to appreciate that when a spine is dysfunctional, all tissues arc involved in such an interconnected way that it is impossible ro discern where one tissue involvement ends and another begins. The VSC model attempts ro organize this new awareness of the fundamentally holistic nature of the human body machine into a conceptual framework that allows chiropracto rs and other hea lth cate providers ro gain a better insight inro the processes involved. The purpose of this chapter is ro present a model of changes in nerve muscle, connective, and vascular tissues that accompany the kinesiologic aberrations of spinal articulations. The development of the VSC is distinctively chiropractic and reflects in a unique way the clinica l practice of chiropractic. Common to all concepts of subluxation are some form of kinesiologic dysfunction and some form of neurologic involvement. The primary form of kinesiopathology that is addressed in chiropractic clinical practice is hypomobiliry, ofren referred ro as fixation. Immobilization degeneration (1) is a term that refers to a consistenr pattern of degeneration in

all tissues associated with an immobilized joint. There is considerable discussion as ro whether partial immobilization can lead ro significant degenerative changes, and such issues can be

appropriately addressed through this model. Another significant facror that can contribute ro subluxation degeneration is trauma, both severe and moderate. Repetitive stress is seen more fre-

quently as contributing ro degenerative changes and dysfunctional states, and continual exposure to vibration, as is common in the workplace or while commuting, are also seen as contriburing ro

degenerative states of the musculoskeletal system. All of these aspects can be adequately treated within the context of the VSc. At least as important as the internal consis-

tency and va lidiry of the descriptive information that constitutes the model is the impact that the model has had and continues ro have on the chiropractic profession itself. The model has provided a common conceptual context in which ro discuss relevant aspects of rhe subluxation con-

cept in a logical and ordered fashion. The model has been the focus of at least one scientific conference and has been a guiding force in the development of technique assessment prorocols by the American Chiropractic Association (ACA) Council on Technique. The model is seen as a natural extension of rhe origina l "bone on nerve" concept, just as rhe quantum mechanical arom is seen

as an extension of the original Bohr atom. It provides a common language for chiropractors ro discuss the many and varied approaches to manipulative and adjustive procedures found in modern chiropractic today, from osseous adjustive procedures, to trigget-point therapies, to

reflex techniques. The VSC addresses the issues of chiropractic in a uniquely chiropractic way but is

also understandable ro any other interested parry. It is a model that can grow and adapt ro new information in areas of neurology and kinesiology and any other relevant ropic. It provides a contextual framework in which students of chiropractic can organize and understand the man y

aspects of the basic clinical sciences relative to adjustive procedures. As an outgrowth of the original subluxation model, the VSC is familiar ro most practicing chiropracrors, who mOSt often

understand the implications and significance of the model implicitly. Finally, the VSC creates a

151 bridge between basic and clinical aspects of spinal degeneration and dysfunction from a distinctively chiropractic perspective. Each diagnostic procedure has a correlate with one or more of the components of the VSC, and clinical outcome measures can, for the most part, be mapped onto the components of the VSc. The VSC as presented in this text deals exclusively with the neuromusculoskeletal components of spinal degeneration and dysfunction as they relate to the chiropractic concept of subluxation. The subtle aspects of psychology relating to the doctor/patient relationship are not addressed, nor do we discuss the socioeconomic factors involved in health and well-being. We shall also avoid the issue of patient satisfaction and quality of life in the context of this model. Although addressing subluxations on a clinical level can have profound effects on an individual's psychological state or sense of self, these ate issues better left to clinical psychology. Our purpose is to desctibe the fundamental natute of spinal subluxation and how the body responds to chiropractic adjustive procedures.

History The VSC model as originally developed by Faye consisted of five components (Table 9-1) . Dishman (2,3) was the first to publish an account of the original five-component model, limiting the histopathology component to a description of cartilage degeneration. Faye, (4) confined the histopathology component to a description of the

OriginalS-Component Model of the VSC

1. 2. 3. 4. 5.

Kinesiopathology Neuropathology Myopathology Histopathology Biochemical abnormalities

The 5-component model originally developed by Faye and first published by DIshman (21.

Neoromuscuiosketetal Components

01 the Verlobrol Suhl.x""" Complex

Biochemical obnormoJitiM

fIgIre 8-1

Organizational model of the vertebral subluxation complex originally published by Lantz (5).

This model includes three components nor specified in the original model and shows [he hierarchic rei arion· ship of the various components. (Lantz CA. The vene-

bra I subluxation complex. leA Review 1989; (Sepl Oct); 37-61.) inflammatory process. A more extensive and substantial formulation of the model (Figure 9-1) included connective tissue pathology, vascular abnormalities, and inflammatory response (5). Since that time, the model has been further refined; pathoanatomy was substituted for histopathology, and pathophysiology was included as a basic component. In this chapter, the pathology terminology has been dropped and a more generic terminology adopted in which the neurologic component is used instead of neuropathology, kinesiologic component for kinesiopathology, and so forth (Figure 9-2). This evolution of the model is shown in Table 9-2.

Overview 01 the Model Figute 9-2 illustrates the hierarchic organization of the VSC in which the components ate seen in relation to one another. The kinesiologic compo-

152

vsc

Neuropathology

InAammatory response

Pathoonotomy

Pathophysiology

Pathobiochemistry

AllIn 8-2 Updated version of the VSC model shown in Figure 9-1. Hi stopathology ha s been re placed by the more generic parhoanaromy. and patho physiology has been added. nenr is represented as rhe apex of our mode l because resroration of marion is rhe central goal in the clinical pracrice of chiropractic. This is in effect the functional end poinr of the combined efforts of rhe tissue components. Movement is affecred by the muscles (myologic component); guided, limired, and stabilized by connecrive rissue; and controlled largely by the nervous system . The vascular system serves the essential nutritive and cleansing role for all tissues and is rhe conduir for rhe immediare srages of the inflammatory response (ar least in vascularized rissues ). These

constitute the tissue-level componenrs of the VSC, and each works in coordinarion wirh the orhers to permit and sustain proper movement. Interference with any single componenr affecrs all others (6). Each tissue component musr be understood rhoroughly to appreciate irs role in spinal parhomechanics and rhe pathologic processes associated with subluxation degenerarion. Each component consists of identifiable elements: rhe interverrebral discs (IVD), articular cartilage, and interspinous ligaments are examples of elements of the connective tissue component; the nerve roots,

153

8 1118 Vertebral 8IMol11lon Complex

Three p hases of evolu tion of the VSC m odel sh owing refinem ent o f th e con cepts a nd terminology

Original

Kinesiopathology Neuropathology Myopathology

Histopathology Biochemical abnorma lities

Updated

Reviled

Kinesiopathology Neuropathology Myopathology Connective tissue path. Vascu lar abnormalities lnflammatory response Histopathology Biochemical abnormalities

dorsal root ganglia, and recurrent meningeal nerves are elements of the neurologic compo-

nent-which can be subdivided further as to segmentallevel: the L5 IYO, the C5 facets, or the Cl nerve roOlS, for example. Changes in these elements are described in terms of anatomic, biochemical, and physiologic alterations, which are called pathologic when they are involved in

Kinesiology Neurology Myology C.T. physiology Angiology Inflam. resp. Anatomy Physiology Biochemistry

discuss kinesiology of joints withour discussing ligaments, capsules, and muscle-tendon systems. In addition, in the spine, the dural sac, along with its contents, must be considered in the kinetics of movement (14,15). The spine is further complicated in its kinesiology in that it responds as an integral unit in which restrictions of movement at

one level can lead to compensatory changes in

degenerative processes, and restorative or thera-

peutic when associated with healing processes. Although the basic components and their specific elements form the foundation of the Y5C, these would be of little value if they did nOt correlate with clinical practice. The model is therefore seen as having three levels of organization (Table 9-3): the basic structural-functional level as illustrated in Figure 9-2, the level of diagnostic evaluation in which each diagnostic procedure maps OntO the basic components, and the thera-

Levels of applica tio n of a compo nent o f the VSC using the kinesiologic com pon ent as a n example

Tx

peutic outcomes that represent the outcome of therapeutic intervention.

Ox

KInesiologic Component

Sx

The fundamentals of kinesiology form the foundation of the kinesiologic component (6-13) . Cerrain features, however, are morc significant when viewed from a chiropracric adjustive perspective.

The most significant details are presented here as a guide for further development. It is difficult to

Adjusting Procedures Traction Thrust Torsion ROM Muscle StrengthIFunction Rheumatology Biomechanics Kinesiology Biochemistry, etc.

Sx, Basic science aspects that form the basis of our under· standing of the component. Ox, Diagnostic procedure associated with the component in question. Tx, Treatment procedures associated with the component.

154

TIle S_luxltlon COIIIpIex

other areas (15,16). No disorder of a single major component of a motion segment can exist without affecting fitst the functions of the other components of the same unit and then the functions of other levels of the spine (6). The basic unit of spinal mobility is the motion segment (7), a three-joint complex (9). Functionally it may be considered to be a single, compound joint with three articulations (10), analogous to the wrist. A typical motion segment consists of two ad;acent vertebrae joined by an lVO, two posterior articulations with their capsu les, and several intrinsic ligaments (8) . Parke (6) includes the muscles and segmenta l contents of the spinal canal and the intervertebral canal (lYC). Atypical spinal motion segments include the occiput-atlas (CO-C1) and the atlas-axis (C1-C2) articulations. The pelvic ring with the two posterior sacroiliac joints and the disclike symphysis pubis a lso has been considered an atypical three-joint motion segment (11). Chiropractic eva luative procedures are often directed at determining specific intersegmental motion or positional abnormalities and correcting

these through specific adjustive procedures directed to those segments (see Chapter 6). Joint movement is a complex phenomenon, more so in

the spine than in any other organ system (12). In addition to the three planes of physiologic movement, flexion-extension, lateral flexion, and roration, there is also long axis traction. Joint play, a springiness in the joint when it is taken to tension, represents the elastic barrier of resistance to

joint motion (see Chapter 6) . In addition to specific intersegmental movement, tegional or gross range of motion (ROM) must be considered, which is far easier to objectively evaluate than segmental motion. It is restriction of spinal ROM that is clinically most notable and most readily monitored as a clinical outcome (15,16) (see Chapter 11). More complex motion, such as gait and dynamic posture, fall into the domain of the kinesiologic component and within the purview of chiropractic.

lmmobilization Degeneration (ID) One of the most prevalent ideas in chiropractic is the notion that restricted motion of the

manipulable subluxation central to spinal degeneration. From the scientific literature it is clear

that all siruations that lead to immobilization cause some degree of degenerative change in the musculoskeletal system, and early mobilization, traction, and continuous passive motion

overcome these harmful effects (17). Lack of movement in a joint leads initially to stiffness (18) and associated pain (19) followed by joint degeneration (1,20) and ultimately fusion by bony ankylosis. The idea that Jomt restriction or

"fixation"

is

an

integra l component of

manipu lable subluxation was first proposed by Smith, Langworthy, and Paxson in 1906 (21 ). More recently, spinal fixations by motion palpation of the spine were formalized by Gillet and Liekens (22 ) and organized by Faye (4) into a system of spinal joint palpation (see Chapter 4). In a study of the effect of interna l fixation on the zygapophyseal joi nts in dogs, degeneration occurred within 2 months of immobilization (23). Human patients with tuberculosis of the spine underwent

ventra l

fusion

with

discecromy,

thereby effectively eliminating movement between the two vertebrae (24). After 6 months it was observed that, in these same patients, fusion of the zygapophyseal joints had also occurred. In the lumbar spines of cadavers, intraarricular adhesions, ranging from thin threadlike filaments to dense mats that preclude any articular movement

(25), were observed in all adult specimens. Restoring motion to a previously immobilized joint leads to normal joint function and physiology. Although the degenerative effects of immobilization may be completely reversed on remobilization (26-28), the extent of and time for maximal recovery are dependent on the duration of immobilization (29) . In extreme cases of immobilization to the point of fibrofatty consolidation of the synovial fluid, remobilization results in the formation of a new joint cleft with articular carti-

155

8 TIle vertebral SUl*lxltlon COIIIpIex lage having normal histologic architecture (26) . This constitutes some of the strongest evidence available supporting a physiologic basis for the effectiveness of chiropractic adjustive procedures. Early mobilization is gaining a foothold in medical programs fot treatment of whiplash (30) and after knee surgery (31). Forced motion causes physical disruption of adhesions between gross structures, such as capsule to cartilage, and leads to a disruption of the intermolecular cross-bridging of collagen (32).

NeIroIogIc Component In the original "bone on nerve" model of subluxation, the nervous system played a centra l role as the mediator of all of the effects of subluxation and, conversely, of the therapeutic benefits of adjustive procedures (33). The neurologic component of rhe VSC has tradirionally been the cornerstone of chiropracric theory (34). Beyond the application of chiropractic and other manipulative procedures as a means

of relieving headache and low-back pain, rhe nervous system has been viewed as the mediator of vitality and health to the individual organs and rissues (35). Increasingly, scientific research supports this fundamental concept of chiropractic (36-39). It is also c1ea~ however, that rhe role the

primary

indicators

of

neurologic

function

observed in the physical examination (43). Spinal Nerves Spina l nerves formed by the dorsal and ventral nerve roots may be impinged by herniated discs (44,45) or by spurs and osteophytes around the joints of Luschka (46) . Nerve impingement from hypertrophy of the zygapophyseal joints also has been documented. Studies now show evidence of successful c hiropra ct ic management of such cases

(47,48). Within the last two decades it has become apparent that not a ll back pain is caused by herniated intervertebral discs, nor do all patients with disc herniation suffer with clinical symptoms (10,49,50). Although patients with herniated discs and nerve impingement may show dramatic

evidence of the effectiveness of chiropractic management

programs,

other

mechanisms

that

expla in the positive results obtained by chiropractic care mUSt be studied.

Dorsal Root Ganglia The integral relationship between the dorsal root ganglia (DRG) and the spina l articulations necessitates that we evaluate the role of these struc-

tures in the subluxation complex (51). DRG lie

nervous system plays in the subluxation comp lex

within the intervertebral canal in close associa -

is far from understood and that fundamental changes in the concept of neurologic involvement in subluxation need to be made. Many aspects of the nervous system's organization and function are relevant to the theory and practice of chiropractic, and many levels of neurologic involvement are reflected in the subluxation complex (40-42). Although compression of

tion with the articular capsule (52,53), except for the first and second cervical segments. DRG contain the cell bodies of all sensory neurons, except for those found in the cranial nerves. Their strate-

the cord, nerve roots, or segmemal nerves may

play a major and often dramatic role in this process, other aspects of the nervous system arc involved as well, from sensory receprofs to inter-

nuncial cells. Pain is by far the most significant factor in a patient's seeking chiropractic carc. In the diagnostic evaluation, motor function, reflexes, altered sensation, and pain responses are

gic location between adjacen t vertebrae make

them prime targets in the causation of subluxation, induced dysfunction, and the focus of chiropractic adjustive procedures. Dorsal rOOt ganglia are far more sensitive to mechanical stimulation than are nerve roots, spina l nerves, or peripheral nerves. When

inflamed, the ganglia become hyperexcitable and give rise to spontaneous discharges (54,55) . Minimal acute compression or chronic irritation lead

to long periods of repetitive firing that last longer than the stimu lus itself; acute compression of

156 peripheral nerves or nerve roots, however, does

not. Aberrant impulses could lead to clinical and pathologic signs and symptoms. The ganglia are richly vascularized (56) and have not been shown to have a blood-nerve barrier. The permeabiliry of ganglionic capillaries is far greater than that of the central nervous system (eNS) or the peripheral nerve (57), and rhis has been implicated as a route of infection by virus

and bacteria (58-61), as a site for the development of chemical irritation and inflammation by bloodborne agents (62), and as a porral of entry for anesthetics injected into the epidural space (63). Any compression or sclerosis that might compromise the arterial supply to or venous drainage from the ganglia is likely to promote irritabiliry, as with peripheral nerves (64). Articular eurology Articular neurology is germane to the theory of chiropractic. Wyke (65) has classified the spinal joint receptors into four rypes-three types of mechanoreceptors and the nocicepwrs. The role

that each plays in degenerative processes, and particularly in pain (66) , is the subject of intensive research. It is known that rhe spinal joints can produce patterns of pain referral (somatosomaric reflex), bur the neurologic mechanisms are nOt well understood (10,67) . Gillette (40) has proposed that coactivation of the articular receptor system and other somatic receptors constitutes a major component of rhe chiropractic

adjustment. The afferent discharges derived from articular mechanoreceptors have a threefold impact when they enter the neuraxis (66,68): reflexogenic effects, perceptual effects, and pain suppression. There is a significant correlation between propri-

oceptive input from the cervical spine and coordination of the extremities (68). There is a discharge of afferent fibers of the knee joint after passive movements of the leg (69). Joint inflammation sensitizes articu lar nociceptors to fire at rest

and

during

normally

nonnoxious

joint

movements (70). The proportion of neurons displaying resting discharges is higher and the

receptive fields are larger in inflamed joints. In humans (7 1), distension of the joint capsule of the knee led to reflex weakening of the quadriceps muscles. Injection of saline into the lumbar facets resulted in pain and significanr increases in the myoelectric activity of the quadriceps (10) or the hamstrings (72), depending on the levels injected. These responses were abolished by intracapsular injection of local anesthetic.

Pain The most common clinical characteristic of patients entering chiropractic offices is pain. Pain is known to be a significant aspect of cervical spinal degeneration (58) as well as of lumbar and pelvic degeneration (66). The mechanism for such pain is related to mechanical or chemical irritation of the DRG, spinal nerves or their roots (58), or specific articular nerves (49,66). Because of the largely subjective nature of pain, its evaluation by clinical methods and objective measures is a challenge to clinicians of all professions (66,73) . For the patient, the experience of pain is real, regardless of whether there are objective clinical findings and, as in the case of phantom pain (74), whether the body part is present. There have been numerous theories proposed that attempt to explain pain (75). One of the more widely discussed is the gate theory of pain (76), in which specific internuncial neurons of the spina l cord control the perception of pain. The transmission of pain sensation through the gate is dependent on the relative input of large (A-beta) and small (A-delta and C) fibers converging on the gate (75). This is one of the major mechanisms evoked in modern theories of manipulative therapies to explain how adjustive procedures relieve pain (41,77,78). Pain assessment is a major undertaking in clinical practice. Numerous methods have been developed to assess pain or to confirm its presence; visual analogue scales (VAS) and other forms of pain scales are widely used in all clinical practice. Evaluation of the pulse rate while pain is elicited is a way of confirming the presence of pain. But despite all of these attempts at quantifi-

157 cation, pain remains a subjective experience, influenced by culture, gender, social status, mood, attitude, and a host of other parameters.

shown that chiropractic adjustments exert a definite influence on pupillary diameter.

Viscerosomatic Relationships

The neurodystrophic hypothesis proposes that neura l dysfunction is stressful to the viscera and other body Structures and leads to "lowered tissue resistance," which can modify the nonspecific and specific immune responses and alrer rhe trophic function of the involved nerves. This has often been evoked by chiropractors to explain the positive results obtained in patients suffering from conditions of a more genera l nature than musculoskeletal pain, such as chronic obstructive pulmonary disease (81), bronchia l asthma, dysmenorrhea, and hypertension (82). Currenr research provides growing evidence of rhe presence of a dynamic interaction between the nervous and immune systems. Histologic studies have shown that mast ce lls are innervated directly by symparhetic nerve fibers, and that this relationship appears to serve a regu latory role in immunologic response (83). These observations are con~istent with those showing a reduction of norepinephrine in lymphoid tissue after an immunologic challenge (84). The evidence supportS the hypothesis rhar sympathetic innervation exerts an inhibitory effect on the immune system and rhat changes in tissue levels of norepinephrine can affect immunologic responsiveness. In animals, sympathecromy of one side of the body leads ro an increase in the development of tumors on thar side (85) . This suggests that interference with the sympathetic nervous system can compromise rhe body's immune system (86,87).

The Nel/rodystrophic Hy pothesis Viscerosomaric relarionships are widely recognized as patterns of referred pain (79). For example, pain associared wirh heart attack is often felr in the left shoulder and radiating down the left arm. Kidney degeneration refers pain to the lowback, and pancreatic degeneration refers pain to the right shoulder and back. Ir has been further demonstrated that skilled examiners can palpate spinal soft rissue changes associared with ischemic heart disease, and can diffetentiate those from changes associared wirh other heart conditions (79). There is little question as to the validity of viscerosomatic reflexes, and the asture diagnostician is aware that somatic pain can herald more serious underfying visceral conditions. The converse process, by contrast, is a hotly debated issue and appears ro be ar rhe heatr of the chiropractic controversy.

So motoallt01lOmic Relationships Somatovisceral relarionships are perhaps rhe key concept of chiropractic theory. The central issues can be divided intO twO complemenrary aspects: (1) Can spinal or paraspinal neurologic dysfunction lead to degeneration in rhe organs supplied by rhe involved nerves? (2) Can chiropracric intervention prevent degeneration and restore vitality to degenerating visceral rissues? This is, perhaps, the mOSt conrroversial issue in chiropractic theory. The evidence, however, tends to support such a concepr. Sato and Swenson (37) have demonstrated that the nerves to the kidneys and adrenals respond wirh reflex impulses when spinal motion segments are larerally flexed passively; the sympathetic response observed was correlated wirh alterarions in heart rate and blood pressure. Clinical studies tend to support these observations. In a randomized, controlled trial (39), it was shown rhat chiropractic adjustments were effecrive in reducing blood pressure in humans. In another human study (80), ir was

Trophic Infll/ences The trophic influences on nerve function have been discussed by a number of authors (89-91) . Severa l compounds are implicated as mediarors of trophic influences (trophic substances) (92,93), wirh acetylcholine being most ofren cited (94,95) . Trophic influences stimu lare more subtle responses in tissues than do neurotransmitters, such as a lrered growth rate (96). Ir is suggested rhar proper vita lity, morphology, and function of

158

TIle . . . .1Ion COmplex

the target tissues are dependent on an adequate degree of trophic stimulation. In muscle, for example, exchanging nerves between "white" and " red" muscle led to white muscle transforming to red and vice versa (97). This line of research gives considerable impetus to the compression models of subluxation . Trophic substances are synthesized in the cell body and transported to the synapse by axoplasmic transport (98) . By compressing the nerve and shutting off the flow of these vital supportive substances, one could explain how the tissues might suffer from degeneration for lack of the chemical stimulation . The amount of force required to cut offaxoplasmic flow, however, leads to serious neurologic deficits that would far overshadow any subtle trophic changes predicted by subluxation models. It remains to be seen, however, whether chronic irritation might lead to excessive trophic stimulation that could lead to tissue hypertrophy or even pathologic degeneration.

Neurodiagnosis In general, neurodiagnostic procedures are not very quantitative, relying on patient complaints such as pain, numbness, or loss of smell or hearing, for the determination of the presence or absence of neurologic involvement (43). Other neurologic tests, such as the visual acuity test or sound discrimination eva luations, can produce quantitative data, provided some amount of sensibility is present, for example, the patient is nOt totally blind or deaf. From a chiropractic clinical perspective, pain, either ongoing or elicited by the doctor during diagnostic tests, is the most readily accessible test of neurologic involvement. Quasiquantitative assessment with instruments such as the VAS are more useful than the purely qualitative assessments, because they permit a more precise tracking of outcome. By noting the specific areas involved in pain, the chiropractor often can derive a refined understanding of segmental levels of involvement of subluxa rion-induced dysfunction, and this is useful in directing the practitioner to the areas to be adjusted.

Neurologic Effects of Adjustive Procedures The most dramatic effects of adjustive procedures are related to the reduction or elimination of back pain (47,48) . Decreased pain appears to be associated with increased range of motion, supporting the dynamic focus of rhe vertebral subluxation complex. Mechanical spinal challenge has been demonstrated also to produce decreased reflex activity in adrenal and renal sympathetic nerves, followed by a rebound increase of activity of the adrenal sympathetic nerves caused by a baroreceptor response. The neurologic as well as the kinesiologic components of the vertebral subluxation complex paradigm offer a rich and varied arena for further study of this model.

ConnectIve lInue Component The major impact of connective tissue changes in the vertebral subluxation complex model is seen with joint immobilization. Joint stiffness (99) or contracture (J 00,101), which is known to increase with age, has been the subject of intensive research because of the use of casting in orthopedic procedures (101) . All connecrive rissue elements are affected by immobilization, each with its own unique pattern of change (20,101 ). Synovial fluid undergoes fibrofatty consolidarion, progressing to more adherent fibrous tissue and ultimately providing a marrix for the deposition of bone salts (26) in the final stages of ankylosis. After joint immobilization, articular cartilage shrinks because of the loss of proteoglycans (102). Its cellular e1emenrs exhibit a reorganization (103), rhe surface develops ulcerations that connect the synovial space with the subchondral bone, and ultimately it shares the same fate as the synovial fluid by ossifying (104). Shrinkage leads to softening of the cartilage, which renders it more susceptible to damage by minor rrauma (105 ). When joints are immobilized, adhesions form between adjacent connective tissue StruCtures (26,103). Forced motion leads to a physical disruption of rhese adhesions as well as a disruption of inrermolecular cross-linkages (32). Adhesions also may form between the nerve root sleeve and

9 llHI Vertallral SlMlxIllon Camplex

159

the adjacent osseous and capsular structures in

bling changes in hypermobile joints. If the discs

the interverrebral canal (106), berween rendons

are analyzed as a unit, the two effects cancel, giving the appearance of no change in the ND.

and articular capsules, or between any two cooneccive tissue structures that come into COntact

and do not move relative to each other. The effect

DIagnostIc Tests

on articular connective tissue depends on the

Virtually all tests for connective tissue integrity are subjective in nature. The standard orthopedic tests are the most accessible and are widely used in clinical practice (43). Passive versus active

position of the joint when it is immobilized (20, 107), a reflection of the forces placed on the respective tissues (1 05,108 ). Age is also important in determining the response to altered forces

motion can give insight into the nature of inju.ries

(109, 110). [n developing bone, excessive pressure inhibits bone growth, whereas a reduction of pressure may accelerate bone growth (111 ). In mature skeletons, abnormal distribution of stresses leads to altered mineral deposition and osteophyte formation (112). Weight-bearing and

and help differentiate berween muscular and connective tissue problems. Palpation is a powerful

motion appear to exert separate influences on the

maintenance of connective tissue (113 ). Ligamentous contracture is widely discussed

as a mechanism for joint stiffness (32) . This may well apply to later stages of immobilization, but in the earlier stages of immobilization degeneration, ligaments become more pliable and compli-

procedure for eva luating connective tissue. Static palpation can provide information relating to specific connective tissue involvement in joint

dysfunction, and motion palpation can give a skilled clinician an indication of segmental stiffness and loss of "joint play" (43) (see Chapter 4) . History and presenting symptoms can also be revealing with regard to connective tissue involvement. Age is a significant factor in connective tis-

sue integrity, and a history of prior surgery or trauma to a joint or region can suggest connective

ant, a condition referred to as ligamentous laxity

tissue involvement. A history or diagnosis of

(100,113-115 ). Alrerations of the point of attachment of ligament to bone after immobilization are also well described (100,116), and this is a signiEcant faeror in the ligament's response to Stress.

osteoarthritis or other arthritides can provide sig-

Most research on joint immobilization has

been performed on extremities, especially knees and elbows (1) and on experimental animals such as rats (103 ), rabbits (11 7), and dogs (109). Studies with humans have suggested that the animal findings are applicable to human spinal degeneration (24,118-120); however, very little research has actually been conducted on the effects of immobilization on the spine itself in either animals or humans. Most of the studies that have been done on the spine are related to scoliosis (112) or lumbar discectom y (24). [n scoliotic

nificant insight. Radiographic analysis is most helpful in deter-

mining the involvement of osseous elements in spinal dysfunction and degeneration (43), but is relatively useless for soft tissue, such as ligaments and articu lar cartilage unless they are ossified. MRl , however, holds great promise for the determination of soft tissue involvement in the subluxation complex and spinal degenerative processes (see Chapter 5). Range of motion analysis is very revealing with regard to connective tissue in volvement,

especially when performed passively. When muscle contraction is not involved in the motion, restrictions mOSt likely indicate connective tissue involvement.

spines, changes on the concave side of the curve

differed from those on the convex side (121 ), the former resembling ligamentous and cartilaginous changes in immobilized joints, the latter resem-

Therapeutic Benefits Little research, if any, exists that directly evaluates the effect of adjustive procedures on connec-

160

1111 Subluxation CGmIIIIx

rive tissue. Results of animal studies, however, are revealing, as are results of medical research using continuous passive motion in promoting healing in injured knees. Restriction of motion of a joint

leads to profound degenerative changes in connective tissue. Return of motion can prevent or

reverse these changes (1). Clearly, if knee joints are allowed to remain motionless after surgery,

they will develop internal adhesions, which will limit mot io n in the future, hence the use of con-

tinuous passive motion immediately after knee surgery. Claims abou nd that regula r adj ustments prevent the development of disc degeneration and, a ltho ugh this sounds plausible, there is no evidence to support this claim. It would be anticipated that simi lar benefits would be bestowed on

degenerative process known as disuse atrophy (122-124). The precise role this plays in joint degeneration is not well understood. Although the changes in muscle function a re often completely reversible (124-127), the time required for complete restoration of muscle function depends on the duration of immobilization ( J24,125). These findings are complicated by the different responses to immobilization by different muscle types ( 124,128-130), as well as by differences in degenerative response related to the position of the joint, and thereby the length of the muscle in the immobilized state (125,131-133). In some cases, the muscle c hanges

3fC

secondary to immo-

bilization, but in turn contribute ro joint degeneration (103). In other instances, such as trauma,

ligaments , tendons , and capsules, but confirma-

congenital anomalies, or diseases that affect mus-

tion of this awaits the appropriate research.

with neuromuscular problems. Historically, chiro-

cles (s uch as polio and muscular dystrophy ), muscle degeneration or pathology can be primary and also might contribute to joint degeneration. It is not always possible to discern the role of muscle in joint pathology, especially of the spine. In particular, scoliosis poses an enigma. Although muscles tend to differ on the concave versus convex

practic

nerve"

sides of the scoliotic cu rve, their contribution to

app roach to managi ng health care problems, and osteopathy, one of the early rivals of chiropractic, espoused the "muscle on vessel" concept. The two schools of thought were dogmatically

the development of the cu rve is nOt understood in most cases ( (34). Current trends in scoliosis theory lean tOward the idea that there is a loss of unilateral regional control of muscle tone or loss of coordination of the righting (postural ) response in the spina l musculature (135, 136). Virtually every significant aspect of muscle structure and function has been eva luated in the context of degenerative changes after immobilization. In studies of induced immobilization of the knee, it was shown that in the early stages of

Myologic Component It is perhaps trivial to state that muscles maintain osseous relationships as we ll as move bones, but such a realization is profound to one who works represented

the

"bone

on

entrenched, and any inclination of one toward the other was anathema. Some in rhe chiropractic

profession sti ll hold to this narrow perspective, but most realize the importance of muscles in the overall function of the human body and are willing to incorporate muscular activity and dysfunc-

tion into their clinical practice. Evidence of this is the close association of chiropractic practitioners with massage therapists and the development of schools of thought within chiropractic itself that address the muscular component as the primary focus of patient management (11 ). O ne of rhe most sign ifi cant aspects of muscular activity from a chiropractic clinical perspective is the fact that, when joints are immobilized, the muscles associated with them undergo a

joint degeneration, restricted joint mobility was

caused almost exclusively by the muscleltendon unit (26); curting the muscle away restored movement ro normal ranges. In later stages, mobility appears to be restricted by capsula r and ligamentouS stricture (118,137) followed by intraa rticular adhesions (132). Muscle tension might lead to excessive degeneration of cartilage by compressing the joint surfaces tOgether (103), thereby con-

9 The VeI'IaIII'1I SUlllllXatIon Complex

161

tributing ro the development of osteoarthritis. A vicious cycle has been described (72) in which muscle spasticity leads to joint contracture, which

immobilized limbs between the tendon and its sheath (138).

leads ro morc spasticity and muscular contrac-

Evalua tive Procedures Evaluation of muscle function and integrity, like that of connecrive tissue, remains largely a clini-

ture. The specified treatment for this condition is ro rerum the joints to their full ROM and maintain that range through the healing stages. Muscle spind les are adversely affected by immobilization, showing significant morphologic, physiologic, and biochemical changes, including shortening and thickening, degeneration of the primary spindle endings, swollen capsules, and loss of cross-striations (138,139) . Physiologic alterarions include increased sensitiviry to stretch and elevation of resting rate of discharge (138,140). One consequence of such an increase in spindle activity would be ro feed excessive stimuli into the central reflex pathways, resulting

in altered efferent activity. This could lead ro the overstimulation of muscle groups that respond to

the stretch reflex leading, in the end stare, to muscle spasm and tender trigger points. Alternatively, such input could lead ro reflex inhibition or failure of joint musculature on challenge (141) . When a joint is immobilized, the effect on muscles depends on their length in the immobilized state ( 133,142) or the angle at which a joint is fixed ( 122). Such changes have been reported for gross morphologic appearance (143) as well as biochemical (144-146) and ultrastructural ( 122 ) characteristics. Shortened muscles show a

cal art. Palpation is used to determine tautness

and tenderness of the muscle mass. Elicitation of pain during active or attempted movement can

indicate muscle injury (43) . Of course, a knowledge of anatomic relationships of muscles ro the relevant osseous structu res is implicit in being

able to diagnose muscle injury and dysfunction. Stretching a muscle by moving its associated joint in an appropriate direction can be revealing as to

the state of the stretched muscle. Muscle testing has long been used to evaluate specific muscles or groups (43). An attempt is made to isolate a specific muscle or group and challenge its strength by manually applying pressu re. In some instances, attempts have been made

to objectify this process by using an intervening air bladder (sphygmomanometer), but the uncertainties .in positioning and cooperation make this

reduction in tension -producing capacity, whereas

approach largely subjective as well. Severa l systems have been developed to determine muscle strength by developing standard reference frames and protocols for determining applied force, using either inflatable bags or pressure plates. With these, as with the handheld pneumatic sensors, problems with reproducibility seriously impair the interpretation of results of such deter-

those chronically stretched retain their ability ro

minations. By contrast, dynamometry recordings

generate force in direct proportion to changes in

of handgrip strength have found wide acceptance in the analysis of upper extremity problems such as carpal tunnel syndrome. All muscle strength

cross-sectional area. Alteration of the distractive forces applied to the Achilles tendon induces extensive cellular and extracellular changes in the musculotendinous junction (146). The distribution of cell types and architecture of the extracellular matrix depend ro a large degree on the type of force applied ro the tissue (compressive versus distractive) (147). Early mobilization of previously immobilized limbs increased the rate of healing in lacerated flexor tendons (148 ), whereas adhesions form in

determinations rel y on relative muscle strength

of the individual's left side compared with the right. This has to be reconciled, to some degree, with the inherent differences in left and right sides relative ro normal handedness. Therapeutic Benefits Directed muscle work is unquestionably beneficial, and numerous reports have been published

162

The SUlllllXaIlon Complex

on the effects of trigger-point therapies, Nimmo receptor tonus procedure, shiatsu, and massage (11). It is often difficult to differentiate the benefits of simply touching someone from rhe benefits of massage, and no doubt both playa role when massage or other muscle work is performed. Cervical traction procedures have been shown ro reduce cervical muscle spasm, and similar

responses have been reported in the lumbar spine (11). Mobilization procedures are used in cervical whiplash injuries to reduce muscle inflammation and cervical pain. Ice is applied to injured and inflamed muscles to slow the inflammatory process and facilitate healing in the early stages of acute inflammation. This can be very beneficial to the patient and facilitates the doctor's task if the patient's pain is reduced (11).

vascular Component Each motion segment is supplied by a segmental artery that passes through the intervertebral canal into the spinal cana l and divides into dorsal and ventral radicular arteries (149), supplying, respectively, the dorsal and ventral nerve roots. These arteries course along with the rOOts and enter the spinal canal, piercing the dura and eventually anastomosing with the spina l arteries and contributing to the blood supply of the spinal cord. Occasionally, one of these carries most of the blood for that segment (56) and such asymmetries may contribute to radicular-type symptoms, possibly through insufficient anastomoses. These arteries are susceptible to the same mechanical forces as are the nerve roots, and if osseous displacement impinges on a nerve or root and leads to compression of that structure, the artery may be compressed as well. Each intervertebral cana l contains, as well, a

segmental vein that drains the spinal canal and vertebral column. The veins are the exit ports for the venous plexus of Batson (150), an extensive

vide a route whereby toxins or inflammatory agents from one area of the spine could influence more remote areas, as is believed to accoum for metastatic dissemination to the spine (150). It is unclear what role specific intersegmental motion plays in regional venous drainage, but it could contribute to clinical symptomatOlogy. In other parts of the body, movement is critical to proper venous circulation (152) . Blood flow increases on resisted rhythmic contraction of the calf and thigh muscles (153) . Immobilization likely leads to localized venous stasis, which effectively creates a negative relative pressure at the area of immobilization. Retrograde venous flow then can bring roxins into the area of immobilization. Whenever venous stasis occurs, there is a reduced

rate of removal of the toxins of metabolism, which, in turn, leads to inflammation and an accelerating degenerative process. Experimental arteria l or venous occlusion is

known to lead to joint stiffness (99), and recent studies have clearly demonstrated that venous occlusion is associated with spinal degeneration. Compression within the intervertebral canal by disc protusion, osteophytes, tumors, or hypertro-

phied bone potentially affects the vascular component before affecting the neurologic structures directly, (151) and veins, because of their thin walls, can easi ly be compressed and occluded. Lack of proper venous drainage may lead to inflammatory states. Diminished venous return leads to

alterations in capillary distribution around joints (154), and a similar mechan.ism has been suggested in immobilized joints (153,155 ). Vascular abnormalities are known ro be contributing or complicating facrors in a range of clinical conditions, including thoracic outlet syn· drome (156), trigeminal neuralgia (157), and ver· tigo (158). The vertebral arteries are known to occasionally develop asymmetrically, with one side making an insignificant contribution ro cra-

anastomosis of vertebra l veins containing no

nial blood flow (159). Similar patterns of devel-

valves to control the direction of blood flow (151). Because of this, venous drainage is dependent on posture and the forces of gravity, which allows for retrograde flow to occur. This can pro-

opment are seen in the segmenta l arteries as well. In addition, vertebral arteries are known to

form loops or kinks within the transverse canal (160), and this is believed to lead to signs and

9 The VII'llIIIrailullluxallon Complex

163

symptoms of cerebral ischemia. Vertebrobasilar

cular system in one of several ways . If srasis ex ists

insufficiency is a contraindication to rotatory

because of a lack of motion, then restoring motion allows the vessels to clear out inflamma-

adjustments to the upper cervical spine (161). Cases have been reported of paralysis, hemiparesis, Wallenberg's syndrome, or death resulting from extreme rotation and extension of the cervi-

cal spine, whether voluntarily (162) or through cervical manipulation (161). Stroke after manipulative procedures may be caused by dissection of the vertebral artery, thrombus formation, and embolic development (43) . Structural anomalies must be considered as well (160, 163). Evaluative Procedures There are virtually no evaluative procedures to determine the integrity of the small arteries and vein, such as the segmental arteries that pass

through

the

intervertebra l

cana l.

Although

tOry exudates. When postural distortions are present, which leads to arterial compression, then

restoring a more normal biomechanical integriry to the body can have a profound effect on the vessels invo lved. It has been postu lated that inflammation around the intervertebral cana l can

lead to compressive edema that cou ld occlude veins or arteries. Restoring motion to those seg-

ments leads to reduction of inflammation and restoration of normal vascu lar integrity. All of these hypotheses are purely speculative, however, because little effort has been put inro understanding the basic mechanisms of manipularive and chiropractic procedures.

angiography can provide such information, its

Innammatory Component

use is limited because of the invasiveness of the procedure, and such information is genera ll y nOt considered clinically relevant.

distinctive component has met with some discon-

Extension and rotation of the cervical spine

have been used to screen for predisposition to vertebral artery compromise, along with a series

of screening tests including eva luation of the patient'S history for vascular problems, blood pressure evaluation, and carotid artery palpation

(43). The effectiveness of these procedures, how-

Identification of the inflammatory response as a tent and conrroversy. Many believe that rhis aspect belongs in the vascular component, and Faye (4), in the five-component model, discusses inflammation under histopathology. The inflammatory response is a composite of cellular and biochemical processes that is largely mediated by rhe vascular sysrem (164), but ir is initiared by local events within the tissues themselves. Highly

ever, has nor been demonstrated.

vascula ri zed tissues, such as skin or muscle,

Venous inregriry is even harder to assess than that of arteries, especia ll y for those veins of inter-

express inflammation very differently than does fibrous connective tissue (165) . Lacerated tendons undergo a repair process controlled by intrinsic

est ro chiropractic and other manipulative proce-

dures. The presence of radicular pain could be indicative of venous obstruction, but such a diagnosis is pure speculation. Phlebography has been used to evaluate spina l venous obstruction (158), but again its use is limited because of the invasiveness of the procedure. For clinical pracrice in chiropractic, it is of lirrle value, but for research

into the mechanisms underlying that practice, the procedure holds promise.

mechanisms that involve recruitment of tissue

macrophages and proliferation of fibroblasts (148). This is more represenrative of a chronic inflammatory response (165,1 66), which a lso leads to an alterarion of collagen types (167, 168), resulting in fibrosis and long-term exposure to the destructive actions of macrophages (165). Immobilization of joints clearly leads to an inflammatory response (155), rhe end point of which is ossification (169) . Inflammatory spillover into

Therapeutic Benefits

surround ing tissue is a critical parameter to moni-

Restoring normal motion to a motion segment could have a direct influence on the intrinsic vas-

tor (170), as implied in the concept of chemical radiculitis (171). It represents one way in which

164 the degeneration of spinal joints may affect the neurologic components. The mOSt obvious clini-

cal manifestation of inflammation is pain, which is the major presenting complaint in chiropractic offices (39) . Arthritis Pain caused by rhe inflammarory processes in arthtitis is perhaps the most obvious atea of inflammation associated with the theory of chi ropractic. Arthritis means simply inflammation of a joint, and it can affect any joint of the body, including the spine (1 14,11 9). All forms of arthritis are associated with pain and decreased movement of the involved joints. When scientists wish to reproduce arthritis in experimental animals, the most common procedure is to immobilize rhe

joints (172-175) . Even in humans, situations that result in immobilization contribute to osteoarthritis (176), which is commonly associated with scoliosis caused by restticted motion of the spine ( 11 9). Restoration of movement can decrease the rate of degeneration or even restore rhe joint to its normal structure and function (177), as seen clinically (178,179) and in basic animal research (17, 180). Thete is a very close association between movement and the brea kdown of connective tissue and the development of the inflammatory processes associa ted with the development of arthritis. Although osteoarthritis, or degenerarive joint disease, is classically considered a noninflammatory condition (181), as many as 75% of cases of osteoatthritis show evidence of inflammation (182). Molecular fragments of collagen (183,184) and proteoglycans (185-187) are inflammarory stimuli and have been associ~ ated with rheumatoid arthritis (188-190), as well as polyarthritis in mice (191) and humans (192), osteoa rthritis (193), and other arthritic conditions (194). The details of this process a re dealt with more thorough ly when we discuss the biochemical compo nent. LnAammation of Nerves and Nerve R oots Inflamed nerves are hyperexcitable (54) and exh ibit behavior different from that of normal

nerves. The DR G of normal nerves respond ro mechanical stimulation by a discharge of action potentials, which stopS on cessation of the stimulus; when inflamed, however, they continue to fire long after the mechanical stimulus has ceased. It has been proposed that the ganglia and nerve roots are affected by inflammarory agents after disc herniation, a process that has been called "chemica l radicu litis" (171). Nerves become inflamed when venous obstruction leads to stasis and edema. Thus, compressive forces in the inrer~ vertebra l ca na l need not directly affect the nerves to impact neurologic func tion . Such processes appear plausible as mechanisms ro mediate the effects of subluxation degeneration. Assessing Inflammation The classic cardinal signs of inflammation are rubor, tumor, calor, and dolor (redness, swelling, heat, and pain, respectively). These characterize the classic acute inflammatory response. Evaluation of these is by observation, interview, and palpation. Heat can be objectively evaluated by thermographic methods and pain can be assessed by rating scales, such as the visual analogue scale (VAS) a nd batteries of que&tions such as the Oswestry pain disability questionnaire. Swelling, o r edema, can be eva luated by observation and palpation; turgor in the area suggests edema, and a pitting of the skin that returns slowly after digital pressure to express accumulated tissue fluids helps to confirm the diagnosis. Redness is readily seen if it i superficial. Assessing inflammation is more challenging if the injury is deep, such as a herniated IVD or zygapophyseal joint inflammation. Localized heat sti ll may be detected by manual palpation or thermographic procedures, and swelling of the deeper tissues often can be palpated. Rubor, in such cases, is impossible to detect. Pain is often considered to be pathognomonic for inflammation, particu larl y if trauma o r tissue damage is suggested . Radicu lar pain is frequently interpreted as a rising from inflammation of the nerves or their rOOts. Localized pain on passive movement is suggestive of joint inflammation, whereas pain on active

9 Tl18 Vlll'llIbrai SUbluxation Complex movement

may

indicate

muscle

or

tendon

involvement. rain elicited by touch is clearly an indication of an active inflammatory process, such as around the ankle joint that has been sprained. Chronic inflammation is much harder to evaluate, especially in the deeper tissues. In superficial tissues, chronic inflammation is identified as scar tissue. In joints and between connective tissue structures, it is characterized by fibrous adhesions. Late stages of inflammation manifest as osteophytes or ankylosis and at this point are not clinically manageable, although they may give rise to problems that continue to haunt the victim. Managing Inflammation Acute inflammation is managed by applying ice to slow the process. In joints, especially those of the spine and particularly the IYD, it is not possible to effectively cool the joint, so other methods mUSt be found to help resolve the situation (11). Of course, medicinally one can recommend the use of antiinflammarory agents, but such measures are outside the purview of chiropractic. Manual procedures, however, can be quite effective in reducing inflammatory srates. Pressure, either applied manually or by means of a bandage, can help to express edematous fluids and restore morc normal rissue integrity. Often a stroking motion with light to moderate pressure will effectively move or "milk» inflammatory fluids from a local edematous area into the general circulation, resulting in a "flushing" of the injured area with fresh extracellular fluid. Simply raising an extremity, such as an ankle or knee, higher than the rest of the body leads to a gravity-assisted flushing of the injured area. Mobilization is a powerful tool for reduction of inflammation. Because immobilization leads to inflammatory changes in the articular tissues, the converse leads to a reversal of that state. Indeed, passive mobilization is widely used to promote healing after knee surgery (179), and passive motion has been used successfully in the management of cervical flexion/extension injuries (30) .

165

Biochemical Aspects 01 the Model ConnecUve lIssue Mechanical failure of ligaments, discs, capsules, or other connective tissue can result from local variations in chemical composition (195). In addition, alterations of the biomechanical forces that Stress connective tissue lead to local changes in the biochemical composition of the tissue (l). We thus have a clearly delineated link between biomechanics and biochemistry as relates to connective tissue structure and function. Collagen forms chemical cross-linkages that hold adjacent collagen molecules tOgether and stabilize its overall structure (32). The numbers of these cross-linkages increase with advancing age (196) and in states of degeneration (197). This is involved in the formation of connective tissue adhesions as are known to form between the nerve root sheath and the articular capsule (26,103). The sulfated glycosaminoglycans draw water into the spaces between individual collagen fibrils. The water contributes to the space-filling properties of the proteoglycans but also provides for lubrication between adjacent collagen fibrils (32,198), especially in fibrous connective tissue. On immobilization of a joint, the first measurable biochemical change is a decrease in proteoglycan, a change that occurs in all connective tissue components of the joint (102). This allows the collagen fibers to approximate each other more closely and facilitates the formation of more collagen cross-linkages (196). The longer a joint is immobilized, the more collagen cross-linkages are formed . This appears to be a mechanism for stabilizing the joint in its new ROM . Remobilization of a previously immobilized joint leads to a disruption of collagen cross-linkages (197,198), as by the high-velocity, low-amplitude thrust that is characteristic of the chiropractic adjustment,

lnnammatlOn Another aspect of connective tissue biochemistry that is significant is the antigenic and inflammatory properties of fragments of collagen (183,184) and proteoglycans (199) . Fragments of

166

TIle SUbluXallon COIIIpIex

hyaluronic acid are potent angiogenic agents; that is, they stimulate the development of new capillaries (200). It has long been believed that rheumatoid arthritis is an autoimmune disease,

with the organism producing antibodies to its own collagen (183). Collagen plays a significant role not only in rheumatoid arthritis (207) but in osteoarthricis and other joint diseases as well

(193,194); antibodies to collagen are frequently found in patients suffering from nonrheumatoid arthritis. Antibodies to proteoglycans exist in rheumatic diseases such as polychondritis, osteoarthritis, and rheumatoid arthritis (191).

lation, but this is a generalized Stress response and not a specific effect of chiropractic adjustive procedures (207). Muscle disuse after immobilization leads to an insulin resistance altering glucose metabolism (208). No doubt other hormonal effects on neuromusculoskeletal tissues have a significant impact on biomechanical function or response, such as the effect of pregnancy in softening the ligaments of the female pelvis to facilitate delivery.

PharmacolOgIC COnSIderations Given the widespread use of drugs by the medical

Connective tissue is known to release specific

profession to treat a variety of diseases and con·

chemical mediators of the inflammatory response called autocoids (186), including a group called

ditions, including musculoskeletal disorders, the effects of drug usage on the course of chiropractic

connective tissue activating peptides. There is an

management programs must be considered. In addition, there is a growing movemenc in the chi·

inflammatory response to tissue injury, such as ligamentous or capsular tear (150), but the inflammatory response to simple immobilization

is less well understood. Evidence of such a response includes the development of pain (19) and the marked alterations of joint morphology seen on immobilization (26, 103). The products of connective tissue degradation could stimulate an inflammatory process as an initial step in tis-

sue remodeling and adaptation to new dynamic joint function, Stich as

limited

motion.

The role of histamines in inflammation must be understood, as well as the events that control their release from the mast cells and other immunologic components (202,203). Similar consideration also mUSt be given to the role of prostaglandins in the pain response (204,205).

ropractic profession toward the use of proprietary and nonproprietary drugs (209). Although it is not the purpose of this chapter to debate the use of drugs in chiropractic, the effects of drugs on human physiology and function cannot be ignored. As an example, the regular use of muscle relaxants might well alter the outcome of a chiropractic adjustment program. Conversely, it is well known that narcotic use leads to a type of muscular rigidity (2 I 0), and such an effect could have a dramatic impact on the patient'S response to care.

The use of injectable and topical steroids to treat inflammatory conditions can lead to adverse

effects (2 I I) that could interfere with effective chiropractic care.

Endocrinology

DIscussion

Serum aldosterone levels have been shown to

The VSC represents the current state of the evolution of the concept of subluxation. It does not identify any single event or process as the sole causative element in the complex process of sub-

decrease after chiropractic adjustments in patients

with hypertension (206). Spinal mobilization resulted in specific sympathetic input into the adrenal gland (36) . Although adrenal hormonal output was not monirored, one would expect a

change of circulating medullary hormones based on the neurophysiologic observations and observed changes in heart rate and blood pressure. Cortisol levels increase after spinal manipu-

luxation degeneration but rather places inco con-

text the various tissues and processes that playa role in this complex phenomenon. It is the author's belief that there is no single identifiable subluxation that accounts for all of the problems and conditions that respond to chiropractic and

9 1be Vllrl8bl'" lWIIuxatlon COmplex

167

other manual therapies, bur rather there are a

trigger-point therapy, etc. It is now time to begin

family or several families of processes. Any par-

of the patient. As an exa mple, patients with genetica lly linked connective tissue disorders would be expected to have a predominance of

to explore the implications of this vast body of procedures and understanding of human response to manual procedures and to tap into the wealth of knowledge of how and why these procedures affect human health. Only by understanding these processes can we hope to evolve further and

connective tissue involvement in degenerative

assume a role of preeminence in health care man-

ticular tissue component may predominate in subluxation degeneration, depending on the stare

processes. The extent to which these lead to biomechanical and kinesiologic dysfunctions that are manageable by adjustive and manipularive procedures defines the role thar chiropractic mighr play in such cases. Similarly, chronic alco holics suffer from neurologic and kinesiologic disorders that may bring them to a chiropractor. The extent to which these problems can be addressed by adjustive procedures is largely irrelevant unless the consumption of alcohol is curtailed. Knowledge of these aspects of human health are essential for the chiropractor as a primary care provider and a holistic practitioner. It is remarkable how human health changes with the changing of the environment in which we live. Today's major problems have shifted from infectious diseases of the turn of the century to degeneracive conditions, such as arteriosclerosis and arthritis of the more recent past, and

toward biomechanical problems, such as repetitive stress injuries, whiplash, and low-back pain in the current era. As health consciousness improves and diet and exercise become morc of a

priority in the daily lives of typical Americans, the biomechanical problems will take on even

agement. As society moves away from the obsession with chemical intervention, only a solid

understanding of the alternatives will provide guidance and comfort for the masses to aid them in the acceptance of new and different approaches to their health problems. The VSC lays the foundation for a solid understanding of the myriad processes involved in spinal degeneration and its effect on human health. By integrating all aspects of spinal structure and function into our understanding of sub-

luxation degeneration and its reversal by adjustive procedures, we can better understand the processes involved and how to correct them. We can approach the development of new techniques and procedures more rationally and with an underst~nding that will give us confidence in what we do. The VSC does nOt prove the existence of subluxations; rather, it provides a context in which

to discuss and understand the processes involved. It does not limit one to a single perception of subluxations but recognizes and describes the various

components and elements that may be involved, how these elements interrelate, and what their

more significance. Chiro practic, because of its

relative importance is in any given clinical situa -

role in managing such disordets, promises to provide a substantial portion of the care for and

sophisticated understanding of what we do and how we do it. Fundamental to chiropractic is the adjustive

tion . It allows each practitioner to identify where he or she fits into the grand scheme of things without compromising the integrity of anyone, regardless of their particular approach to patient management. It provides a common language for the development of dialogue, not only between chiropractors and other health care providers, but

procedure, which has undergone a dramatic evo-

among chiropractors themselves.

lution in the past century, from the excessively forceful procedures of early chiropractic pioneers to more refined osseous adjustive procedures and subtle reflex techniques, nonforce procedures,

Although the VSC dea ls only with the neuromusculoskeletal aspects of subluxation degeneration, one must not lose sight of the profound effect that correction of subluxations can have on

treatment of such conditions. It is essential, therefore, to develop more realistic models and more

168

1l1li s.mmllllon complex

a patient's life. When a person is dysfunctional because of pain and integrity is restored by adjustive procedures, what profound emotional and psychologic effects would that individual experience? The VSC allows for every aspect of chiropractic clinical management to be integrated into a single conceptual model, a sort of "unified field theory" of chiropractic. Each diagnostic procedure can be mapped into one or more of the components, and specific therapeuric effects of adjustive procedures can be assigned to specific tissue components or their elements. Each component can, in turn, be described in terms of precise details of anatomic, physiologic, and biochemica l alterations inherent in subluxation degeneration and parallel changes involved in norma lization of structure and function through adjustive procedures . Still, we have seen those who cling to the arcane ideas of a prior century use the VSC as a paradigm to promote their outdated ideas. We cannOt afford to let this distract us from the value in the mode l as it is presented in this chapter. Conversely, many who have denounced the concept of subluxation see the VSC as just another th inly vei led rationa lization of a cultist group using unproven procedures. These, too, have lost sight of rationa l enterprise, for their objections are based on past perceptions and nOt on the current State of knowledge. The VSC was designed [0 bring understanding to an area that was fraught with confusion; it was crafted to be consistent with known rationa l thought and valid information; it was designed to adapt to a growing body of information and understanding of the function of the human body and how the physical machi nations interrelate with what we call human health.

References 1. LantZ CA. Immobilization degeneration and (he fixation hypothesis of chiropractic subluxation. Chiro Res J 1988; 1,21-46. 2. Dishman RW. Review of the lircmwre supporting a scientific basis for the chiropractic subluxation com plex. J Manipulative Physiol Ther 1985; 8: 163-74.

3. Dishman RW. Static and dynamic components of the chiropractic subluxation complex: A literature review. J Manipulative Physiol Ther 1988; 11 (2):98-107. 4. Faye LJ . Motion palpation of the spine. Huntington Beach, Ca lifornia: Morion Palpation Inst Pub, 1983. 5. Lanrz CA. The vertebral subluxation complex. ICA Review 1989; (Scp/Oct ):37-61. 6. Parke WW. Applied amnomy of the spine. Chapter 2. In: Rothman RH, Simeone FA, cds. The Spi ne. Philadelphia: \'(fB Saunders, 1982. 7. Nachemson AF, Schulrz AB, Berkson MH. Me

Evaluation for Manipulable Subluxations

01II1I'I1 ........ A11111111"

Clinical Rationale Provides Logical Method for Model ClassHication Models of pathophysiologic processes traditionally result from attempts to explain empirically observable clinical phenomenon. Such IS the case with mantpulable subluxatlons. The historical models represent isolated attempts to do so. Research in this arena has occurred primarily wlthtn the osteopathic profession (27,28). With morc interest heing generated in spinal manipula-

tion as a result of several clinical trials dcmonsrranng effectiveness in the treatment of back pain, more attention is again focusing on possible

• History • Physical examination

• Special studies (radiographic imaging. clinical laboratory tests, etc.) . lclllnlCll _ _

• History of mechanical etiologies • Static structural asymmetries • Dynamic structuraVmechanical asymmetries • Static palpation • Motion palpation

• Imaging of structural alterations (radiographic, functional capacity testing, motion analysis, etc.)

178 ing vasoconstnctlon or dilation (thermography), and sudomotor activity (galvanic skin response). Standard neurologic indicators including hyper-

>

Models of Chiropractic Subluxation

reflexia or hyporeflexia, sensory changes, and

motor changes also may suggest spinal dysfunctions. Some consider altered tissue texture and edema as indications of aberrant local tissue metabolism or vascularization (rubor, tumor,

dolor, calor, etc.). All healers recognize the role the patient's psyche and lifestyle plays in the function of the body's somatic structures. Mental attitude, social

interactions, lifestyle habits, and Stress may induce muscular tightness that leads to more anxiety and contributes to abnormal muscle tension. Attempting to break the cycle with a spinal adjustment has been a clinical option taken by many manipulators.

When assessing the purposes of manipulation,

it is clear that aberrant mechanics, neurologic activiry, trophic function, or psychosocial problems are addressed. The argument then is made that a classification system for models of manipulable spinal lesion and subluxation should be based on these commonalities of generic clinical practice rather than "brand-name" theories. Spe-

cific explanations of the vertebral subluxation within each of these four general categories of biomechanical, neurologic, trophic, and psychosocial models are presented and summarized in the box. Rationales, explanations, and brief reviews of relevant literature of these clinically derived models are presented in the following discussion.

• Vertebral malposition • Fixation caused by adhesion • Fixation caused

• • • •

by meniscoid entrapment

Fixation caused by nuclear fragmentation Disc deformation caused by tissue creep Hypennobility and ligamentous laxity Mechanical joint locking

IIItnItItIIc ........ • Nerve, root, DRG compression or traction • Spinal cord compression or traction • Somatosomatic reflexes • Somatovisceral and viscerosomaric reflexes • Motor system degeneration • Psychoneuroimmunology ,...Ic ........ • Aberrant axoplasmic transpon • Intraneural micrcx:irculation ischemias • Macrcx:irculation ischemias • Altered cerebrospinal fluid flow Payl ..... cl.......

• Placebo effeCt • Stress reduction • Lifestyle modification

regarding radiographically demonstrable articular disrelationships. Trauma, disc degeneration, ero-

sive arthritides, and congenital factors all have been shown to cause such radiographic changes. However, reduction of such mechanical alter-

Models of Chiropractic Subluxation lIIom8chanIcai Models Vertebral Malposition One of the oldest concepts of subluxation considers trauma to be a major cause of altered joint position. Palmer (12) and Still (30) both discussed this model, and Leach's (5) chapter on intervertebral subluxation reviews medical literature

ations has not been demonstrated with manipula· tion. More subtle mechanical alterations are probably what chiropractors adjust, which are difficult ro demonstrate radiographically (29). The clinical value of radiography for such assessments has been questioned (3 j ,32) (see Chapters 5 and 8). The concept of a static misalignment, although promising initially, seems difficult to support. Chiropractic studies have thus far shown interobserver and intraobserver agreement of

10

n-..1Ic Modell 01 CI.....·1CIIc Slauxallon

many technique-based x-ray markings ro be relatively poor (32). Some radiographic mensuration methods indicating disc wedging and overa ll articular contours can be evaluated consistent ly

and are sometimes used as indications for mechanical therapies. However, good quantitative outcome studies clearly identifying usefulness remain ro be done. Although this mechanical approach may potentially ind icate aberrant segmental position, it also may be representative of activity of surrounding muscularu_re. Discussion of the larrer lies within the domain of neurologic models, specifically somatosomatic reflexes. Mechanically, the "out-of-place bone" is not likely ro be the sole explanation for chiropractic subluxation . Fixation Caused by Adhesion Adhesion in and around synovial joints may arise in two ways. It may result from trauma resulting in extracellular accumu lation of inflammatory

exudate and blood (33). Platelets then release thrombin-converting fibrinogen inro fibrin, which organizes into collagenous scar tissue, resulting in

a variety of soft tissue and articular adhesions. A second type of adhesion results from the dehydration associated with immobilization. Extensibility of connective tissue is caused

by infusion of water

between layers of proteoglycan molecules. This provides lubrication, allowing for a more parallel configuration and greater stretch under longitudinal tension (34 ). Immobilization leads ro dehydration with resultant app roximation of the proteoglycans, which tend to stick rogether, creating movement restrictions (35,36) . Another by-product of prolonged immobilization can be intraarticular fatty ad hesion within synovia l joints (37). The relevance ro spinal lesion models is that both trauma and immobilization are frequently implicated causes in patients with subluxation.

Manipulation increases movement in dehydrated tissues, promoting the imbibition of fluid, or the actual mechanical shearing or breakdown of newly deposited adhesions. This model explains many clinical phenomena and is supportable based on the literature (38).

179

Fixation Caused by Meniscoid Entrapment Bogduk and Engel (39) and Giles and Taylor (40,41) have reported on the presence of intraarticular synovial tabs or meniscoids. These tabs may cause fixation when the fibrocartilaginous edge of a tab gets caught between the articular surfaces (42). The resultant deformation and restriction, especially at end range, is also thought ro stress the joint capsule from which the men iscaid originates. This may result in irritation of [he capsular nerve endings and may contribute to

pain and spasm . Meniscoids appear to be present throughout the spinal facet joints (42,43). However, problems with this model have been identified (36) : meniscoids may not be present in fixed joints, and most meniscoids may actually be softer than the joint carti lage and therefore may be more likely ro be deformed or cleaved by the joint (38). Disorders such as rheumaroid arthritis appear to have associated proliferation of synovia l tabs (42), yet there does not seem to be any reporting of increased likelihood of fixation in these kinds of individuals. Although the potential is promising for some kind of role of synovial tabs, particularly as instigarots of muscle spasm (39), or perhaps through extrapment where the meniscoid becomes trapped beyond the articular facets, they do not seem likely to be the primary cause of subluxarion. Fixation Caused by Nuclear Fragments This model suggests that, through movement, a portion of the disc's nucleus pulposus pushes through weakened sections of the anulus fibrosis. A sequestrati on may occur on subsequent movements, impeding normal movement between the

end plates. Such restriction (as well as resultant muscle spasm) may resu lt in fixation (44) . Disc derangements have been implicated in manipulable spinal lesions for some time (45-47). Sandoz (48) suggests that long axis manipulation coupled with rotation could suction the fragment centrally. It has been suggested by Farfan et a l. (49) that the layers of the anulus migrate, permitting the disc ro withstand large amounts of compression before a second ruprure. However, manipu-

180 lators report fixation in joints without discs (for examp le, the atlanooccipira l junction, or the

sacroiliac joints) (24,50). Fixations seem to occur in younger individuals in whom disc degeneration is not a likely contributing factor. Further contradicting this model are arguments pointing out

that the earliest degenerative anular changes begin at the periphery and work centrally (51). Additionally, there seems to be little evidence of nuclear fragmentation on autopsy (51) . Disc Deformity as a Manipulable Lesion Radiographically observable changes in intervertebral disc alignment have been used as an indicator of subluxation (52,53). Prolonged compressive loading of a disc has been shown to lead to tissue creep deformity (54) that results in degenerativelike changes in anular composition. Manipulation of such discs has nOt been shown to alter either configuration or composition of Structures having undergone such tissue creep. However, it is reasonable to suggest that mechanical stresses (manipu lation, stretch, exercise)

directed in an opposing manner may help slow progressive degenerative changes. In light of Weisel's report (55) of a significant incidence of disc herniation in asymptomatic patients, the role

such trophic and biomechanical changes play clinically remains speculative.

Mechanical Joint Locking From a purely mechanical point of view, Steindler (56) noted that tropism in the lumbar spine, in which one facet faces relatively coronally while the other faces more sagitally, can lead to the sagittal facets mutually locking on each other. Farfan and Sullivan (57) describe this locking as the "cam" effect of the facets when one facet is rotated against its "fellow." They contend that the more coronal-facing facet fails to resist torsion as sheer force, with strain of higher magnitude than usual falling directly on the disc corresponding to the level of disc pathology and the side of disc herniation. Cop lens (58) suggests that tropism or asymmetry of the apophyseal joint causes diminished mechanical efficiency, leading to limitation of motion that may be readily relieved by manipulation. A change in the axis of rotation allowed by the slight translation in the vertebra l motion segment can screw down the inferior facets, twisting

them like an eccentric cam, and jamming them against the cuplike superior facets (59). Gravity and muscle spasm then continue to hold the facets in a locked position. A mechanical locking from a slight shift in the axis of rotation of the sacroi liac joints has also been described by Turek (60) (see Chapter 26) . The immediate relief often experienced after manipulation makes this theory

appea ling. Hypermobility and Laxity as Manipulable Lesions It is obvious that a lax joint is not likely to be mechanically benefited by manipulation. It ca n be argued, however, that hypermobility and the resultant irritation may lead

[Q

muscle spasm and

symptomatology that cou ld respond to mechanical stimuli. Manipulation of an unstable segment seems unlikely to promote greater instability, provided such manipulation is properly appl ied wit hin the joint's physiologic range. However, this approach would probably be temporary and palliative. Some have suggested that hypermobile segments resu lt from fixed or fused segments at an adjacent level (51). Instabi lity then may be an

Nerve, Nerve Root, and Dorsal Root Ganglion Compression or Traction Nerve compression

is of historical

nOte as

Palmer's "foot on the hose" theory (12). He suggested that nerve energy cou ld be reduced or increased from pressure applied by the vertebra . Leach (5) summarizes the debate on this model in his chapter on nerve compression. Early work by Hadley (61,62) suggested that nerve root compression could result from radiographically demonstrated intervertebra l subluxation. However, CreJin (63) tried to refute this. He attempted

indicator for assessment of surrounding areas

to close an electric circuit between wires placed

(see Chapter 8) .

along the nerve and inside of the intervertebral

181

10 11Ieoretk: Modell 01 ChroprIC1lc SUl*lxallon foramen in cadavers. Manual forces applied along all ranges of motion were unable to close the circuit. Both his methodology and conclusions could hardly be considered unbiased and do nOt

spinal canal pathology (75). Cord and neura l ele-

accounr for structural variants such as the trans-

ment distortion caused by traction also provide a

foramina l ligaments or functional alterations such as edema (64).

rationale for craniosacral techniques (76). Breig et al. (77,78) have investigated the mechanical relationship of the meninges with the spinal cord and the osseous vertebra l column. Distortion of the cervical spina l cord caused by stabilizing attachments of the dentate ligaments has been observed with normal cervical flexion (76,79) . The rationale for this hypothesis appears to be

Given that there 3 rc other structures within

the foramen (blood and lymphatic vessels, far, connective tissue, etc.), the possibiliry exists that

other kinds of mechanical stresses may affect the nervous sy tern. Luttges et al. (65,66), Triano and Luttges (67), and MacGregor et al. (68) have demonstrated that mechanical pressures and tensions may create a myriad of subclinical neuro-

physiologic a lterations. These range from changes in intraneural protein composition to altered nerve conduction characteristics. The dorsal foot

trauma consequence leading to sudden infant

death (74). Additionally, cord and thecal sac compression are well recognized as a complications of

sou nd, but no evidence exists to show that mechanical vertebral or cranial restriction is

capable of placing the kinds of force on cord structu res that creates a ltered neurophysiology.

seems to be more sensitive to sma ll amo unts of pressure and tension than the efferent anter ior

Somatosomaric Reflexes

root or the nerve itself (69). The magnitude of tension on rhe posterior root required to effect a

hypothesis (14,80), the somatosomatic reflex model suggests that the highly innervated soft tis-

change may be within the scope of mechanical

sues around joints may become irritated, which

Sometimes referred to as the proprioceptive insult

edema

may lead to reflex modifications in postural tone

around the foramen or capsule, but this has not been experimentally verified. The dorsal roor ganglion (DRG) is a disrinct structure also in the vicinity of the intervertebral foramen. Lantz (70) points out the exquisite sensiriviry of rhe DRG ro mechanical stresses. DRG

and neural integration of posrura l accivities.

distortion

possible

from

traction

or

compression has been implicated as a cause of

pain in stenosis, disc bu lge, fibrosis, etc. The distinction berween nerve rOot and DRG is primarily anaromic, but Lantz notes that a sign ificant

aspect of DRG physiology is that the cell bodies of the DRG undergo trophic changes when the nerve is injured peripherally (71). Concerns regarding the kinds of mechanical forces needed to affect the DRG are the same as those outlined previously for nerve rOOt compression and traction.

Spinal Cord Compression or Traction B. J. Palmer was perhaps the first proponent of this model of subluxation (72). It has served as a basis for upper cervical chiropractic techniques (73) and has been implicated as a post-birth-

Wyke (81,82) has suggested that spinal manipulation stretches mechanoreceptors in the joint cap-

su le. This stimulus has an inhibitory effect (mediated through cord interneurons) on nociceptive activity of the type IV endings. This mechanism has been called the pain gate (83) . Gillette (84) has expanded on this model by providing a detailed

accounting

of

[he

various

somatic

mechanoreceptor populations in the lumbar fascia. Although Wyke (81) has documented that joint capsule stretch can inhibit pain, Gillette (84) specu lates that this phenomenon has the potential to be initiated by other nerve ending populations as well. Another example of a somatosoma ti c reAex

involves reflex muscle spasm (85,86) . This is a positive-feedback cycle mediated by the gammamOtor loop in which a spasmed muscle may result from and contribute to proprioceptive irri-

tation. This has been referred to as the "facilitated segment." It appears that spinal cord segments in [he vicinity of a spina l fixation have a

182 lower threshold for firing (27,28,85). There is some evidence for the reduction of muscle spasm as measured by electromyography after spinal adjusting (87,88). Perhaps one of the most promising models of the manipulable subluxa-

organic disorders, most patients that present to chiropractors self-select for neuromusculoskeletal conditions (98,99). The outcome literature for somatic interventions on organic problems has

been relatively limited, dated, or anecdotal.

tion, somatosomatic reflex pathways seem to

explain many of the clinical observations seen with spinal adjusting. In and of itself, this model does not represent any kind of pathologic lesion; rather it suggests a mechanism by which spinal adjusting and manipulation has an effect on reduction of pain and spasm in the absence of any specific spinal lesion. Somatovisceral and Viscerosomatic Reflexes This model attempts to explain effects manipulation might have with organic disorders. Early osteopathic research in this area concluded that vertebral lesions in a nimals may affect vascular supply to various glands and viscera (5). Sato and Swenson (89) demonstrated sympathetic discharge in rats by placing mechanical stresses into the spinal joints. Somatic stimulation by manipulation has been shown to affect gastric function (90) and angina pain (9 1). Early work by Speransky (92) suggested that somatic blockade injections at segmental spina l levels have a beneficial effect on the progression of lobar pneumonia. Spinal lesions have been clinically associated with deep visceral pain (93). In addirion, physiologic effects of somatic stimulation by mechanical means have some early experimenta l support (9497) . It is reasonable to consider that certain organic disorders may contribute to development

Motor System Degeneration The Eastern European manual medicine movement has theorized a model of peripheral and somatic "blockages" and their role in affecting integrated function of the motor system from cortex to periphery (24,26,100). This model offers a considerably different role for spinal or extremity dysfunction than other neurologic models. Two kinds of nervous system integration can be described. The first is termed "vertical integration," which refers to the relationship between

(1) the centra l nervous system (CNS) structures; (2) the spinal cord; (3) peripheral nerves; and (4) musculoskeletal structures. The second, " horizontal integration," refers to the relationship between anatomica ll y adjacent or related structures within any of the four vertical components

(for example, motor cortex and cerebellum from group 1, knee and hip from group 4, etc.) It is well known that in upper moror neuron lesions degeneration of function follows in both horizo ntal and vertical directions and that loss of function becomes morc permanent over time. For examp le, after a cerebrovascular accident, neuro-

of segmental somatic muscle tone changes. Some

logic firing patterns change in the vicinity of the lesion, leading to reorganization and changes in related CNS Structures (horizontal degeneration). In addition, there is a gradual cumulative functional change vertica lly in the cord and peripheral

early osteopathic animal research provides evi-

nerves, which eventually leads ro muscular atro-

dence that somatic interventions (a djustment,

phy in the affected peripheral structures. The motor system degeneration model argues that a lesion in any of the four vertical levels (including a peripheral joint lesion) leads to subtle and gradual functional alterations vertically and horizontally throughout the motor system. Treatment and rehabilitation programs by modern manual medicine and physical therapy practitioners have

injection, etc.) may influence the progression of a sma ll number of organic conditions. What is clearly speculative at this point is the role that spinal lesions have in the development of these organic disorders. Clear manipulative treatment

protocols and quantitative outcome studies for different kinds of conditions are also lacking. Although both chi ropractic and osteopathic prac-

centered on distinctions between acrive (patienr-

titioners report anecdota l successes with various

performed ) care and passive (doctor-performed)

183 care (101). It is thought that treatment of peripheral joint lesions (including spinal dysfunction) needs to be more than passive mechanical work (for example, spinal adjustment). Because of the holistic nature of the entire moror system, C3fe mUSt include exercise and retraining along lines similar to those involved in rehabilitation of other motor system pathologic conditions (such as upper motor neuton lesions). The longer the condition is left to progress, the greater the likelihood that recruitment (vertical and horizontal) of other areas of the motor system will occur, leading to recurrence of the peripheral lesion (22) . Psychoneuroimmunology Just as somatosomatic reflexes may be considered a component part of the motor system degenerarion model, somatoautonomic and viscerosomatic

reflexes may be considered a component part of psychoneuroimmunology. Attempts to quantify the relationship of psychological considerations with immune system function as mediated through the endocrine and nervous systems are

being made. Because of the intimate relationship berween [he nervous system and the endocrine

system, the specialty of behavioral medicine has taken a particular interest in psychoneuroimmunology (102). Ader's (103) text on the subject reviews literature and concepts that support the

role that various psychologic and behavioral factors play in physiologic function. The field, although controversial (104), has a rational basis and a large literature base that seems to correlate behavioral syndromes and interventions with clinical phenomena and outcomes (l05). In the previous discussion of the mOtor system, it was suggested that somatic injury can provide sensory input to the nervous

system, leading to horizontal and vertical integration with resultant long-term patterning. It is reasonable to speculate that a chiropractic adjustment, which might influence somatoauronomic activity, could also contribute input to higher CNS centers that may be important in psychoneuroimmunology relationships. With increasing interest in neuroimmunology research, this

model is likely to develop greatly. Exact neural pathways and neurophysiologic responses are not well identified nor understood, and chiropractic applications of this model remain speculative (see Chapter 14 ).

1rophIc Models Aberrant Axoplasmic Transport It is known that axonal transport can be affected chemica lly (106,107), and mechanical stresses have been shown to alter intracellular protein metabolism (69). This model suggests that mechanical or chemical stresses (from metabolism of traumatized tissue) may alter nervous system physiology. Singer (108) describes how nerves provide trophic sustenance for muscle growth and maintenance. He further states that axoplasmic flow can be affected without damage to nerve conduction. Manipulation'S role would be to free up mechanical pressure, perhaps in the soft tissues, which may impede axonal transport. However, no studies exist that demonstrate changes in axoplasmic flow with spinal or soft tissue manipulation. Also unclarified are the details regarding the extent and kinds of mechanical pressures possible with spinal or soft tissue lesions. lnrraneural Microcirculation Ischemias Because the blood vessels supplying nerve tissue are softer and more susceptible to compression than are the nerves, a likely candidate for a spinal lesion is localized neuroischemia. The symptOms of neurapraxia are understood clinically (109) and often manifest as paresthesias. This model is closely related to the axoplasmic transport model in that one of the major consequences of neura l ischemia is altered intracellular metabolism of the nerve and resultant aberrant axoplasmic flow. A detailed review of the experimenta l literature in this area has been provided by Sjosrrand et al. (110) . This model has been a favorite of the osteopathic profession, but suffers the same limitations as the previous model: absence of documentation regarding the kinds of pathoanatomic lesions that cou ld lead to ischemia.

184

TIle SUbluXation CCJmpIex

Macrocirculation Ischemia (Aberrant Vascular a nd Lymphatic Supply)

variety of head symptoms and postural disorders. Much of the literature surrounding the biome-

This model serves as an extension of microcirclI-

chanica l model of cord compression and traction

lation ischemia as applied to larger blood vessels and lymphatics. Many clinical syndromes involv-

is applicable here. This speculative rat ionale suggesrs that a condition of CSF stasis or aberrant Aow leads to decreased nutritional supply to those CNS components bathed by the Auid. Surgical case stud ies can be found showing that a complete obliterarion of the subarachnoid space can lead to obstructed CSF flow and resultant arrophy of neural elements ( I J 7). However, this

ing tissue contracture or space-occupying lesions can impede larger vessels. To what exrenr spinal dysfunctions can influence larger vessel flow is

debatable. Although mechanical stresse can impact on cerebral blood Aow, many documented cases of mechanical impingement are secondary to excessive trauma and may nor be manipulable.

Verrebrobasilar arterial insufficiency afrer cervical manipulation has been imp licated as a cause

of stroke ( 111 ). Therefore, predisposition to vascu lar insufficiency is a possible conrraindication

to certain kinds of cervica l adjusting (J 12).

IS

far

removed

from

minute,

manipulable

mechanical srresses allegedly cau ing subtle alterations in the nutritive capaciry of CSF. The exact mechanisms of this model are perhaps best discarded in favor of direct subtle mechanica l effects of meningeal traction on eNS components.

Because functional mechanical stresses associated

with spinal manipulation may significantly affect cephalic circulation, it is reasoned that manipula-

tion may have beneficial effects as well as negative ones. The significance of this model is that chiropractic adjusting has been implicated in the resolution of a wide variery of cepha lic symptomatology ( 113, J 14 ). Although neurologic expla-

Psychosocial Models Placebo Effect The placebo effect has often been cited as a source of the effectiveness of spinal manipulation

nations may account for some of these effects, possible vascu lar consequences have nOt been

by its detracrors ( I 18). Yet the therapeutic va lue of the placebo effect shou ld not be overlooked ( I 19). It is important for providers to recognize rhe mind-body relarionship and the role rhat the

adequarely considered. Although mOSt of the lit-

doctor-patient

erature regarding this mechanism centers on cervical vascu lature, thi s model might be extrapolated to other anatomic regions where mechanical inrr usions on vascular elements may occur.

Placebo has too often been used to explain away the unknown whi le confounding psychological

relationship

has

in

healing.

responses with sources of experimenta l design variabi lity, such a measurement error, sampling

error, etc. (l20 ). Cherkin and MacCornack ( 121) Altered Cerebrospinal Fluid Flow Improper circulation of the cerebrospinal fluid (CSF) has been suggested as a mechanism in spina l dysfunction that is amenable to manipulation (78, 11 5). Movement of the cranial bones secondary to pressure changes within the cranium

may be responsible for a pumping acrion that circu lates CSF (78, 11 6). Craniopelvic manipulation is thought by some to normalize aberrancies of

have compared patient satisfaction between family practitioners and chiropractors in back pain

patients and noted higher degrees of confidence and satisfaction with chiropractors. This was att ributed to the chiropractors' ability to commu -

nicate clearly and believably with their patients. Although Cherkin and MacCornack did not attribute any portion of patient satisfaction to adjustive care itself, the point is demonstrated

this movement. It is unclear what the exact clini-

that the patient'S belief in both the practitioner

cal consequences of impaired CSF flow would be, but specu lat ion based on clinical experience has

and the treatment plays an important role in the hea ling process. Interestingly, another report

suggesred the va lue of this approach for a wide

noted that almost half of the family practitioners

10

n-,,1Ic Modell 01 CllII'GIII'acllc saxallon

stated that they use the placebo effect therapeutically with their back pain patients (122). Fewer than 5% of the chiropractors stated rhat they did so. Part of a placebo's effectiveness may come

185

clinically by education on environmenta l and lifesryle modification. Although many of these problems may not always be considered as the primary instigators of joint dysfunction, chiro-

from the practitioner's lack of awareness of, or

practors have recognized the importance of

unwillingness to acknowledge, placebo effects. Placebo certainly constitutes a portion of the therapeutic effect of any health care approach (123). The extent to which it has an effect in chiropractic practice is nOt clearly quantified, bur it does serve as one of the possible models or explanations of the effectiveness of spinal manipulation . Practitioners need nOt be fearful or belittled

trauma, roxicity, and autosuggestion in health and disease since the time of D. D. Palmer (J 2).

by

elucidation

of its

extent

in

chiropractic.

Placebo is perhaps the most noninvasive of approaches, and its role should be maximized, because it truly lIses the patient's own recuperative ability. The only caveat is that this should not

Often the doctor's recommendations for changes in lifestyle ca n be the active ingredient in a therapeutic response. The chiropractor who casua ll y suggests a change in posture or activity at the

work station may very well give full therapeutic credit to the passive component (spi nal adjustment) while neglecting to consider the role played by the lifesryle modification.

Conclusions

serve as a Justification to avoid seeking under-

Whether it is ca lled manipulable subluxation,

standing of other possible physical mechanisms.

manipulable lesion, chiropractic subluxation, somatic dysfunction, fixation, or "bump in the

Stress Reduction Selye (124) articulated the role emotional stress plays with the endocrine system and muscle tension. High anxiety and stress levels have been implicated in a number of muscle tension and

other clinical syndromes (125). Spinal adjusting may help relax tense muscles as outl ined in the somarosomaric reflex model, yet many chiropractors go further with relaxation exercise, biofeedback, lifestyle counseling, nutritional guida nce, and related procedures. For the sake of completeness, stress needs to be considered as a possible mechanism in the mediation of spinal dysfunction, especially in cases in which muscle tension

and joint fixation fail to resolve with a reasonable

back," this clinical phenomenon brings millions of patients to doctors. Perhaps communication

and collaboration among various interested parties will advance our understanding in this area.

D. D. Palmer ( 126 ) first noted the problem of multifactOrial terminology when he wrOte the following: Too many manufacture rheir own definition of terms . .. . What would be the result if each banker and broker should invenr and persist in using his own devised addition and multiplication rahle. Herein arises the discordant. inharmonious jan· gling among chiropracrors regardmg what constl· tutes the principles of science . ...

Chi ropractors are ga inin g greater acceptance

3moum of carc.

into the mainstream of sociery's health ca re deliv-

Lifesryle Modification

ery systems . As such it is becoming imperative that our concepts, procedures, and professional

In addition to stress, many of the actlvl[lcs of

daily living are likely contributors to spina l and joint dysfunction. Repetitive and prolonged posrural activity, either static or dynamic, nutritional neglect, inadequate or improper exercise, and roxic exposure are examp les of numerous areas that manipulative practitioners might address

identiry be clarified not only for others, but for ourselves. Emphasis also IllUSt be placed on adopting meaningful and supportable terminology and classifications for subluxation models. Opinionated, histOrically and politically motivated definitions of subluxation (or other terms) are no longer adequate to explain the myriad of

186 effects spinal adjusting is thought to have (8). The chiropractic profession is being called on to quantify and describe both our effectiveness and our rationales. Without this, the barrIe for equal access to patients in an ever-decreasing supply of health care resources becomes even more difficult. Distinctiveness about chiropractic cannOt be centered on vague or outdated and inaccurate concepts. An understanding and appreciation of the state-of-theart about what is known, supported, and speculative on "manipulable subluxation" is essential for the future. Doctors of Chiropractic require a common starting point for interdisciplinary dialogue. Such investigation and collaboration can lead to input from our perspective into the health care delivery system along with clinical refinements and developments that result in better patient care.

Ra'1II'8I1C88 1. Brantmgham JW. A su rvey of the lIterature regarding the behavior, palhology, etiology, and nomenclature of the chiropractic lesion. ACA J Chiropractic 1985; 19(8H5-70. 2. Brantingham JW. A critical look at the subluxation hypothesis. In: Hodgson M cr aI., cds. Current lOpics In chiropraCTic: reviews of the literature. Sunnyvale, Cali· fornia: Palmer College of Chiropractic-West 1987; DU-6. 3. KeaungJc. Science and poillics and the subluxation. Am J Chiropractic Med 1988; 1(3),107-10. 4. Dishman RW. Review of the literature supporting a sciennfic basis for the chiropractic suhluxanon complex. J Mampulative Physiol Ther 1985; 8(3):163-74. 5. Leach RA. The chiropractic theories: A synopsis of scientific research, 3rd ed. Baltimore: Williams and WilkinS, 1994. 6. Moorz RD, CiRulio Bl, Haney PL. The existence of the manipulable spinal lesion. In: Coyle BA, ed. Current topics 111 chiropractic: Reviews of the literature. Sunnyvale, Califorma: Palmer College of Chiropractic-West, 1984; 1lhysio) Therap 1994 Uune); 17(5),302-309. 11. Lomax FL. Manipulative therapy: An historical perspecrive from ancient rimes. In: Goldsrein M, cd. The research sratus of spinal mampulative [herap)". NINCDS Monograph 1975; 15,11-15. 12. Palmer DO. The science, art and philosophy of chiropractic. Portland, Oregon: Portland Printing House. 1910. 13. Palmer BJ. Fight to climb. Davenport. Iowa: Palmer School of Chiropractic, 1950. 14. Homewood AE. The neurodynamics of the vertebral subluxation. 3rd cd. St. Perersberg, Florida: Valkyrie Press, 1979. 15. Janse J. Principles and practice of chiropractic. lombard, illinois: Narion:ll CoUege of ChiropraCtic, 1976. 16. Faye LJ. Mmion palp::H1on of the spine. Huntington Sc:ach, Califorma: Motion Palpation Institute, 1983. 17. Lann CA. The vertebral subluxation complex.ICA ReVIew 1989; (SeprlOct),37-61. 18. Still AT. Philosophy of osteopathy. Kirksville,l\1issouri : The Author, 1899. 19. H-ICDA.llospital Version of ICDA. 2nd cd. Commission on Professional and Hospital Activities, 1973. 20. Greenman PE. PrinCiples of manual medicine. Balttmore: Williams & Wilkins, 1989. 21. Mennell JM. HIStory of the development of medical manipulation concepts: Medical ternunolog),. In: Goldstein M, cd. The research ~tatus of spmal mampulatlVe therapy. N1NCDS Monograph 1975; 15,19. 22. Cyriax J. Treatment of pam hy manipulation. In: Goldstein M, cd. The research status of spinal manipularj\'e therapy. N1NCDS Monograph 1975; 15,19. 23. Paris SV. Spmal malllpulative therapy. Clm Orthop 1983; 179,55. 24. Lewit K. Malllpulauve therapy 111 the rehabilitation of the motor system. 2nd cd. London: Butlerworths, 1991. 25. Janda V. Muscles, central nervous regulation and b----0"

A

: ()

F~

'E

Figure 11·3 Three-joint complex of the lower cervical spine. Anterior elements: A, anterior longitudinal ligamenrj B, anterior anulus fibrosus; C, posterior anulus fibrosus; D, posterior longirudinalligamenr. Posterior elements: E, coscotransversc liga mentj F. capsu lar ligament; G, articu lar facet; H, ligamentum

flavin; I, interspinous and su praspinous ligame nts. (White AA, j ohllsoll RM, Palljabi MM, SOl/thwick \\'l0. BiomecIJal1;cal analysis of clinical stability in the

cervical spille. elill Orthop 1975; 109:87.)

a

translational movement (1). The fundamenta l unit of spinal movement referred to as the motion segment (2) is a threejoint complex (3). This unit consists of an intervertebral disc surrounded by two adjacent vertebrae, the two posterior joints, and th e surrounding contiguous ligaments, including capsules (Figure 11 -3) . This forms the functional unit of spinal motion. The potentia l exists for a spina l joint to

exh ibit translational and rotational movements along and around each of the X·, yo, and z-axes. Thus we characterize a motion segment as a viscoelastic, energy-absorbing entity, possessing six degrees of motion (4·7) . Specific motions or resultant positions are defined by the axis around which movement takes place a nd the plane th rough which movement occurs. The Illmions of fl exion and exten-

11 Klneslolagy: An Essential Approach Toward UndeI'stlllllllng the ChIropractic SubluXation sian occur about the x-axis and through the sagit-

tal plane. Lateral Oexion occurs about the z-axis in the coronal plane. The longitudinal axis (yaxis) is vertical and allows axial rotation through the transverse plane. The origin of motion is the Intersection of the three planes and is convention-

ally placed in the center of the superior vertebral body in the spinal motion segment. Therefore, conventional segmental spinal motion is

described in terms relative

to

the subadjacenr

superior vertebrae.

The potential for six degrees of freedom originates frol11 the unique arrangement of the threejoint complex, with the separation of the verte-

bral bodies by the intervertebral disc allowing for

193

translation in all directions. Although the amounr of motion permitted in each segment is slight, pri-

marily restricted by the posterior facet joint anatomy and plane of the joint surface, this multilinked mechanical system of motion segments allows for a wide range of overall spinal motion. Coupling of more than one degree of freedom occurs when rotation or translation of the vercebrae about one axis is consistently associated wirh rorarion or translarion of rhat same vertebra

about another axis (8). Jofe et al. (9) state that coupling is primarily caused by the geometry of the regional facet articulations, and the connecting ligaments and curvature of the spine playa

secondary role. A rigid body's motion also can be described with reference to the instantaneous axes of rota-

tion (tAR) and hel ica l axis of motion (HAM) . At every instant in plane motion, there is a line in

the body or a hypothetica l extension of it that does nOt move. This line, which is perpendicular

Position 1 _ _ _ B,

to the motion plane, is the instantaneous axis of

rotation (Figure 11-4) (8). The helical axis of motion js defined as a unique axis in space that

completely defines a three-dimensional motion of a rigid body from position 1 to position 2 (10). It is analogous to the instantaneous axis of rotation

B.

for plane Illation . According to the laws of mechanics, a rigid body may always be moved from position 1 to position 2 by a rotation about a certain axis and a translarion along rhe same

axis ( 10). This constitutes helical motion . The motion of a screw is an example of helical motion. This concept has been introduced in the thoracic spine and investigated in the lumbar spine. A given Agare 11-4

Insranrancous axis of rorarion. Graphical

technique of determining the instanraneous axis of rotation when a hody moves from position I to

posicion 2. The axis is found to be ac the inrersection of the twO perpendicular bisectors of translation vectors AI·A z and 8 1,82 of any twO poinrs A and Bon rhe

instantaneous

axis

of

rotation

depends on the Structure as well as the type of loading. The calculation for a particu lar vertebra differs as a result of various combinations of force and movement (8).

body. (WIllie AA. Panjaln MM. Clmical biomechamcs

Analysis 01 Motion

of th" spme. 2/1d ed. Pln/adelplna: fB Lippmcott,

The analysis of normal and abnormal motion

1990:6S9-60.)

requires a system of measurement that can reli-

194 a bly produce high-quali ty, high-resolution images in a simple, accurate, and repeata ble manner. The ra nge of motion was studied initia lly in cadave rs (4,5, 11 ,12) before the advent of x- rays. This posed difficulties beca use of postmo rtem changes that occurred w ith cadaver specimens, thus not accurately reflecting spina l mobility. But in vitro studies co ntinue, attempting to simulate

motio n without the physiologic muscle forces present. In vivo procedures have been developed but a re too complex to perform in a practica l manne r.

Radiographic imaging of living subjects is ge nerall y the initial imagi ng modality of choice. Sta ndard radiograph ic series provide static information onJy, capturing the structural status of the

,

,,

,,

,,

, "...J Rgure 11-5 Movement di agra m o r tem plate analysis. The so lid lines represent extens ion of C2-C4, and [he interrupted lines depic t flex ion o f C2-C4 . These can be superimposed onto an image of C2-C4 in ne utral (nor shown ), Analysis of intersegmenral translation and rora tion can then be performed. (From Penning L. N ormal movements of the cervical spi,Je. Am J Roentgenoi 1978; 1]0:3 17-26.)

11 KiI8aIoIogy: An ElI8II1IaI Approach Toward Underllaldng the ClIII'1IjIi'ac1lc SUl*Ixatlllll spine in one plane. " Functional" tadiographs depict [he instantaneous positions of a vertebra at the extremes of global range of motion . Although individual segmental movement cannot be assessed, aberrant motion may be identified as

restricted or increased or as abnormal vertebral alignment at the end of a given range of motion. Various authors used template analysis (13) and "moror diagrams " from these radiographs to

quantify motion (Figure 11 -5) (14-17). Dimnet et al. (18,19 ) studied lateral cervical radiographs in full flexion, full extension, and three intermediate motions to detect angles and cemers of move-

ment for each vertebra (18). This same procedure was used earlier in the lumbar spine to observe lumbar sagittal plane motion (19 ). Coupled motions out of this plane, however, cannot be

observed . Dynamic evaluation of spina l motion has

been advocated by many authors (20) using stress

195

radiographs. Stress radiographs consist of fronta l rad iographic views of the spine whi le the patient is placed in maximum rig ht and left latera l bending, and late ral views of the spine whi le the patient is positioned in maximum lumbar flexion

and extension (20). More sophisticated and costly imagi ng techniques are now available, such as biplanar orthogonal radiography. Radiograp hs are taken simultaneously throug h two x-ray tubes arranged at right angles to one another (Figure 11-6). Movement in all three planes can be detected and quantified (21-26). A year after Roentgen's discovery of the x-ray in 1895, fluoroscopic screens were introduced, allowing for x-ray observation of dynamic events (27). In 1921, investigators began using cineradiography. This process documents fluoroscopic examinations by photographing a fluoroscopic screen with 16-mm or 35-0101 motion picture fi lm

lolerol

source

source

Agure 11-6 Biplanar radiographic technique. Geometric construct ion showing [he projection of points on a body onto (wo o rthogonal planes. (Pea rcy M. Burrough S. Assessment of bony union after interbody fusion of the lumbar spine using a hip/anar radiographic technique. J Bone Joint Surg 1982; 64B:228-3 2.)

196

The SUblUXation Complex

(27) . The film could later be viewed at real-time, slow motion, or freeze-frame speeds. By the late 1950s, several researchers began to apply cineradiography to the skeletal system to eva luate joint motion (28-30). This technique allows for the srudy of dynamic motion with the contribution of the joints, disc, ligaments, and muscles. Cineradiography requires increased radiation dosages and poses difficulty to the investigator in quantifying the enormous amount of data. The widespread availability of video recording systems in the 1970s and 1980s led to the inevitable replacement of cineradiography by videofluoroscopy. Serial x-ray images were digitized from an image intensifier and directly interfaced to a computerized image processor. This digitized and displayed selected fluoroscopic images on a computer monitOr. This spinal imaging modality is subject to observer variation in measuring angles and operator inconsistency

(31). It has potential in evaluating asymmetrical or paradoxical motion and intersegmental motion with low radiation exposures. Newer techniques such as dynamic computed tomography (CT) and magnetic resonance imaging (MRI) are being

~ 11·7

used to visualize three-dimensional moving images (27). [n conclusion, the cost, dose, and yield must be evaluated before choosing a method of imaging to assess spinal kinematics.

Regional and Intersegmental Range 01 Motion The physiologic range of translation and rotation of a vertebra for each of the six degrees of freedom are explored in the cervical, thorat.::ic, and lumbar spine. The reader should be aware that the literature spawns a wide range of techniques used to evaluate and describe ranges of motion . This will inherently cause conflicting data when quantifying and qualifying motion. In addition to this factor, biologic variation is always at play.

Cervical Spine Atlantooccipital Joints The atlantooccipital joint is formed from the articulation of convex occipital condyle and con-

Flexion and extension of the occiput on the atlas. During flexion the occipital condyles glide posteriorly and superiorly on the lateral masses of atlas, as the occipital bone separates from the posterior arch. During extension, the condyles slide anteriorly on the lateral masses of arias, while the occipital bone approximates the posterior arch of arias. (From Bergmann TF, Peterson DH, Lawre"ce DL. Chiropractic technique. New York:

Churchill Livingstone, 1993:219.)

11 Kinesiology: An EHen1IaI AppI'IIICh Toward IInderstald ng the ChIropractic SUbluXatIon cave atlas facet . This is a symmetrical and mechanically linked joint (32). These joints produce predominarely sagitta l plane movements of flexion and extension, as rhe condyles slide in rheir corresponding lareral masses of the atlas (Figure 11-7). Controve rsy exists as to the amount of movement, with as little as 13° reported by Werne (33) and White and Panjabi in rad iographic studies (7). Fielding, using cineroentgenography, evaluated sagitta l motion at 35° (29). Penning performed overlay studies on 20 healthy adults to find an average of 30° sagittal motion, with a range of 25 to 45° (34 ). Panjabi et aI., in later studies, concluded an average range of 24.5°, approximately 21° of extension and 3.5° flexion (35). In a stud y reported by Jones, two patterns of total cervical flexion exist (36). Cervical fl exion initiated with the chin retracted produces greater motion at the

CO-C1 segment than flexion sta rting with the head erect. Most authors agree that pure rotation cannot occur (S,9,33,36). However, Kapandji, in studying this unique joint believes that rotation

between CO and C1 (3 degrees) is seconda ry to rotation of the atlas a bout the odontoid, accompanied by secondary minimal linear displacement to the same side of roration, and lateral flexion on the opposite side (Fig ure l1-S) (32). Dvorak et aI., using Cf, eva luated the maxi mal rotational excursion of this joint as 10.25° (37). Penning and Wilmink reported a mean value of 1° rOtation at this level using CT sca ns (3S). Panjabi et a l. discovered as much as 7.2° axial rotation (o ne side) using stereophotogrammetry (measurements derived from three-dimensional photographs) (35). White and Panj abi report an approximate So lateral flexion determined by a review of the literatu re and their own a na lysis (S) . Werne in his ea rlier studies on cadave rs contended 11.9° lateral bending with slightl y less, 7.So on radiographs (33). Panj.bi et a l. found less lateral bending of 5.5° using stereophotogrammetry (35). It wou ld appea r that lateral flex ion of the atlanco-occipital articulation is limited not only by the osseous geometry but by the alar ligament attachment

197

~

11 ·8 ROtation at [he atlanrooccip iral joint. Rocarion of the occiput to the left is associa ted with an anteri or displacement of the right occipita l cond yle on

the right lateral mass of the adas (arro", 1). At the same rime tension develops in the adanrooccipiral ligament, pulling the right occipital condyle to the left (arrow 2). There rotation of the occiput to [he left is associated with a linear displacemem of 2 to 3 mm to [he left and lateral flexion to [he right. (From Kapandji IA . The rhysiology of the joints. Vol. 3. The trunk and the vertebral column. Edinburgh: Churchill

Livingstone, 1982,182-3. )

(Figu re 11-9) (10). Penning contends that lateral bending of the a rlantooccipital segment is always combined with the lateral bending and slight rotation of the C1-C2 joint (34 ). Coro nal plane rotation and transverse plane rotation occur in the opposite directions because

of the convex shape of the occipital condyles and concave shape of the arias articular surfaces. Thus ipsilateral latera l flexion is coupled with rotation of the head to the opposite side (10,29,39) . On lateral fl exion to the left, C1 translates to the left to adjust the position of the left lateral mass of C 1, which otherwise would prevent the left side flexion (Figure 11 -10). T he right a lar ligament is pulled tight by this movement, pulling on the dens, rotating the C2 spino us process to the right. Jirout contradicts this theory in his x-ray analysis of rotarional synkineses of occiput and

198 Alar ligaments from behind Occiput

A

len bending of head

Left latera l flexi on of the upper cervical

spine (solid arrow) with tran slarion of rhe arias (broken Q"ow) roward rhe lefr. (Bergmann TF. Peterson DH, Lawrence DL. Chiropractic technique.

New York: Churchill Livingstolle, 1993:223.)

B

f111t1'111-8 The role of the alar ligamentS in lateral flexion of atlanrooccipiral articulation: A, posterior

view in the neutral position; B, left lateral flexion. Motion is limited by the right upper portion and the left lower portion of the alar ligaments. (Bergmann TF. Peterson DH, Lawrence DL. Chiropractic technique.

New York: Churchill Livillgstone, 1993:220.)

atlas on lateral inclinarion (39) . He reports that in nearly half of his 322 cases the rotation of the atlas from the side of inclination cannOt be looked on as normal a nd constant, because it does nOt occur.

Translatory movements at the oceipitolatlanto complex are small, 0 to 1 mm (9, 10). The instantaneous axis of rotation for flexion-

extension is located in a sagittal axis 2 to 3 em above the apex of the dens (to). For lateral bending the axis appears to be located in the midline slightl y more distant from the tip of the dens (40) . Because there is very little or no axial rOtation at the occipiroarlantal articulation, the instantaneous axis of rotation for this plane is nor

considered (Fieure II-Ill.

Atlantoaxial Joints This mechanically linked four-joint complex lacks the disc of the typical vertebral motion segment (41 ). There are rwo paired atlantoaxial joints, one central atlantoodontoid joint, and one joint between the transverse ligament and the posterior

aspect of the odontoid process. Thus the pattern of motion is primarily controlled by the geometry of the osseous and ligamentous articu lations.

This joint exhibits predominately rotation of the atlas around the y-axis of the odontoid process. Werne evaluated the amOunt of move-

ment as 47°, constiruting 40 % to 50% of the axial roration of the neck (33). This is supported by Panjabi and White in their 1978 article (8). Penning and Wilmink discovered 40 .5° of motion to either side, with a range of 29 to 46° (38). Less motion is reported by Dvorek et aI., with an average of 32.2° (37). Panjabi et al. also found less axial rotation of 38.9° (35). Coupled motion exjsts during rotation, with a

"screwlike" mechanism allowing the atlas to drop 2 to 3 mm because of the biconvexity of the joint surfaces (Figure 11 -12). There is an associated ipsilateral lateral bending to a small degree (34). This vertical approximation was confirmed by Hohl in cineradiographs (42) . Werne concluded that the vertical displacement depends on

11 Kinesiology: An EnentIaI AppI'tIICb TOWII'd 1JI. .·.ta.... 1he CIIII .......:1Ic Subluxltlon

199

on the superior facets of C2. In flexion, the posterior joint capsule and posterior arches separate and the atlas articular surface glides forward. In extension the posterior joint capsule and posterior arches approximate and the arias articular

surface glides posteriorly (44). Panjabi er al. report 11.5° flexion and 10.9° extension at the atlanroaxia l joint (35). These similar measurements were confi rmed by Werne and Hohl, who demonstrated 10° of flexion a nd extension (33,42). Penning, using movement diagrams from functional radiographs to study flexion and extension, found on average 30 of motion with a range of 25 ro 45° (34). It is generally accepred that there is no measurable lateral flexion at the atlantoaxial joint (9) . Penning (34) reports a mean value of 10° to each side. Panjabi et al. report 6.7" of lateral flexion to one side at rhe atlantoaxial segment (35) . Q

B FiIIII'I1Hl The approximate location of the lAR (dot ) for rhe atlanrooccipital joint in the frontal plane, right and left lateral flexion (A). The location of the

lAR in the sagittal plane, nexion and extension (8 ). (From White AA. Panjahi MM. Clinical biomechanics

of the spine. 2nd ed. Philadelphia: ] B Lippincott, 1990:96.)

the extent to which the longitudina l axis of the dens correlates with the imaginary longitudina l axis of the body (33) . The more parallel the two are, the more distinctive the vertical displacement

(33). Jirout (43) used x-ray analysis ro formulate conclusions regarding rotation and linear displacement. In his model, rotation had two phases, with the initial phase involving a symmetrica l roration of C2 around rhe longitudinal axis of the cervica l spine (attributable ro the facet joints), followed by an asymmetrica l phase of further rotation (influenced by the addition of muscle traction), with pronounced lateral translation of the axis against the atl as. Flexion and extension require the anteri or

arch ro slide up and down on the odontoid process as the C I inferior facets ro ll and slide

Flexion and extension movements of the

atlantoaxial joint are associated

with small

translational movemems from 2 to 3 mm in

the adu lt and up to 4.5 mm in the ch ild (10). The atla ntodenta l interspace a lso diminishes during fl exion, creating a V-shaped appeara nce (29). Although there is still controversy as to whether lateral (x-axis) translation of the atlan toaxia l joint occurs, most of the literature

suggests that a displacement of 0 to 4 mm is normal (9). The instantaneous axis of rotation for the atlantoaxial joint is located by cineradiographic studies in the middle third of the dens for flexion and extension (Figure 11-13) (33) . For axial rOtation, the axis may be assumed to lie in the center portion of the axis (Figure 11-14 ) (9). Because lateral flexion at this joint is sma ll or nonexistent, the location of an axis for this motion may be deemed irrelevant (40) . Lower Cervical Spine The lower cervica l spine from the second to the seventh vertebra possesses six degrees of motion: flexion, extension, rotation, and lateral flexion . The range of morion is determined by osseous geometry and the stiffness of the disc (7) . Move-

200

The SubluxlUon Complex

Neutral

Rotation

fIgUre 11-12 The coupling of vertical translation of C 1 with axial translation of C i on C2. (Bergmann TF, Peterson DH, Lawrence DL. Chiropractic technique. New York: Churchill Livingstone, 1993:222.)

ment is not isolated to anyone segmental level but generally is accompanied

by simi lar motion at

ather levels (4S). Sagitta l plane motion (flexion and extens ion) predominately occurs in the lower cervica l spine and is accompan ied by translation and roration

(Table 11-1). The upper vertebrae in the motion segment tilt and glide on the arricu lar surfaces of the lower facet joints, producing the total motion required by the head and neck (Figure 11 - 15) . The coupled translation that occurs with flexion and extension has been measured at approximately 2 mm per segment, with an upper range of 2.7 mm (9,46). In the sagitta l plane the z-axis translation

occurs

in

decreasing

magnirude

approaching the C7 vertebra (8), producing a "stair-step" effecr. In addit ion, for every degree of sagittal plane rotation, morc translation occurs in

the upper cervical segments than in the lower cervical segments (44 ). This tran lation has been anribured [0 the inclination of the facet joints (29) . Conversely, the caudal segments tend to have a larger amount of tilt (14 ).

Younger individuals may possess a general physiologic ligamentous laxity, demonstrating disproportionately greater motion at C2-C3, unlike most adults, who show the greatest flexion sagittal motion at C4-CS or CS-C6 (47). On flexion, C2 appears to subluxate several millimeters anteriorly, bur maintains the integrity of th e spinolaminar junction line (3 4 ). Rotation in the lower cervical spine never occurs in isolation; it is accompanied by some degree of lateral flexion (Table 11 -1) (32). Ranges of motion for segmental axial rotation on average are slightly less than those for lateral flexion, with a similar tendency for decreased movement in th e lower cervical segments (4 4 ). Lateral flexion averages approximately 10' to each side in the midcervical segments, with decreasing flexibility in the caudal segments (Table II- I) (44). Lateral flexion in the lower cervical spine is coupled with rotation such that ipsilateral lateral bending is coupled with rotation of the spinous process to the contralateral side (or convexity of the curve) (Figure 11 - 16 ). The

201

11 Dlestology: An EssenUai Approach Toward lInderatandIng the ChIropracllc SUbluXadon

Rotation

ofe]

C2 Rgare 11-14

Rep resenrarion of the approx imate location of the IA R for axial rota ti on of C l an C2. (Wlhite A A, Palljabi MM . Clinica l biomechanics of the

spille. 211d ed. Philadelphia: JB Lipp illCOlI, 1990:96.) figure 11-13

A, Represemarion of sagittal plane morion of Cl an C2, wi th approx imate IAR also

indica ted. B, The anrerior curva ture of the dens may permit some degree of additio nal sagitta l plane morion in both rota tion and rrans larion. (White AA. Palljabi

MM. Clinical biomechanics of the spine. 2nd ed. Philadelphia: JB LippillCOlI, 1990:93.)

>

degree of coupled motio n decreases in a ca udad direction (44 ). At the second cervical ve rtebra, there is 20 of coupled axial rota tion fo r every 3 0 of lateral bending, a ra tio of 2:3 (9). At the seventh ve rtebra, there is l Oaf coupled ax ial rotation for every 7.5 0 of

Limits and Representative Values of Rotation of the Cervical Spine

Interspace

Comblnod Flllion/Eltonsion (..·.'i. rotation) lImill of R.ng .. Representative (dogr.es) Angl. (dogrees)

Ono Sido lateral Bonding (,·axi. rot.tlon) limit. of Rango. (dogree.)

Representative

Angle (dogrees)

Ono Side Allat Rotation (y·.,I. rot.tlon) lImlll of Ranges (dogrees)

Ropresentatlvo Anglo (dogrees)

0-10 3-10 1-12

3 7 7

2-12 2-10 0-7

7 6 2

Middle

C2-3 C3-4 C4-5

5-16 7-26 13-29

10 15 20

11-20 9-15 0-16

10

13-29 6-26 4-7

20 17 9

0-16 0-17 0-17

8

11 11

wwer

C5-6 C6-7 C7-Tl

7 4

Whi te AA III, Panjabi MM, cds. Clinical biomechanics of the spine. 2nd cd. Phila delphia : JB Lippincott, 1990.

202

C2

C4

Filll'ell-1B Movement of the facet surfaces in rhe lower

C7

fIIIII't 11-15 A diagrammatic approximation of the relative regional cephalocaudal variations in radii of curvature of the arches, defined by the cervical verrebrae as they rotare and translate in the sagitta l plane. (From White AA, Palliahi MM . Clillical biomechanics of the spine. 2nd ed. Phjladelphia:}8 Lippillcott, 1990:99.)

late ral bending, a ratio of 1 :7.5. Jofe theorizes that the gradua l change in coupling ratio may be related to the change in inclination of the facet JOIntS (9). The greatest obliquity of the facet joints is at C2-C3 (40° to 45°), progressively

lower cervical spine causes coupled rotarion with lateral nexion. (Bergmann TF, Peterson DH, Lawrence DL. Chiropractic technique. New York: Churchill Livillgstolle, 1993:233.)

decreasing to 10· at C7-T I (32). Kapandji also believes that during lateral fl exion some degree of extension occurs as a result of anatomic structure (32) . Penning and Wilmink, using CT, discovered that during latera l flexion, to avoid the uncinate process imbrication, the superior vertebra performs a translation in a con tralatera l direction (38) . Because the unciform process is located posteriorly on the edges of the vertebral bodies, this mechanism takes place only posteriorly (41). With posterior translation of the upper vertebra with respect to the lower verteb ra in rhe opposite direction during lateral flexion, simultaneous rotation must occur (4 1). Fielding adds that becallse of the inclination of the intervertebral joints, du ring lateral flexion, the in fe rior articular processes on the concave side glide downward and backward, whereas those on the convex side glide upward and forward, thus producing the mO'ion of rotation (29) .

11 Kinesiology: An &l1lil1li AppI'OICII Toward IDIerlllld nl the ClIII"IIPI'1Ctic SW*uIItion Viewing all of the available data, it would appear that the highest intersegmental movement is located in the midcervical spine level. There appear to be only a few studies that give indication of the location of instantaneous

axes of rotation in the cervical region. Lysell postulates these locations based on judgment from observations of patterns of motion rather than on quantitative assessment (48 ). The IAR for sagittal and horizontal plane motion is located in the anterior portions of the subadjacent vertebrae (48). The instantaneous ax is of rotation for lateral fl exion has not been determined (Figure 11- 17) (48).

Thoracic Spine The thoracic spine is an area of transition from

the transversely situated facets of the cervical spine to the sagitally orientated facets of the lumbar spine. The principal movements that take place in the thoracic region are flexion, extension, rotation, and late ral flexion. Nevertheless, motion

is limited in all planes because of the ribs, narrowed discs, and elongated spinous processes. Combined flexion and extension in the thoracic spine averages approximately 6° per motion segment and increases in a cephalocaudad

Flexion/ extension

lateral bending

203

direction (44). Movement averages 4° in the upper thoracic spine, 6° in the midsegments, and

finally 12° in the lower two motion segments (Table 11-2) (10). As in the lower cervical spine, sagittal plane motion is accompanied by rotation with slight sagittal plane translation . Translation is uniform but markedly less than that of the cervica l spine (10). Lateral flexion averages approximately 6° to each side, with the lower two segments averaging 7 to 9° (Table 11 -2) (44). Data on the coupled motion (rotation and lateral flexion ) in the thoracic spine are less convincing because the resu lts

have been somewhat varied, depending on the segments studied (7). In the upper thoracic region the pattern mimics the lower cervical spine. The coupling is such that ipsilateral latera l bending occurs with the vertebral body rotating into the concavity and spinous process deviation to the convexiry. The degree of lateral bending produces somewhat less axial rotation than it did in the cervical spine (8) . In the middle and lower thoracic spine, the coupling is less distinct and may occur in any direction, bur it is genera lly assumed that the lower thoracic segments have a tendency to follow the coupling pattern of the lumbar spine (44 ).

Axial rotation

E~F R~L

fIIII't 11 ·17 Th e approximate locatio ns of instantaneous axes of rotation in the lower cervical spine. F is the location in going from a neutral to a flexed position. E is the location of the lAR in going from a neutral to extended position. L shows the axes in left axial rotation, and R shows them in right axial rotation. The question mark indicates chat there are no convi ncing estimates of the lAR for lateral bending in the cervical spi ne. (White AA. l'aniabi MM. Clinical biomechanics of the spine. 2nd ed. Philadelphia: JB Lippincott, 1990: 102.)

204

The SUbluXation C8mp1ex

>

Limits a nd R ep resenta tive Valu es o f R o tatio n of th e T h oracic Spine

Comblnod FIOIlon/Ellon.lon (..-axl. rolallon)

Intenplea

lImli. of Rang .. (degree.)

Tl-T2 T2-T3 T3-T4 T4-T5 T5-T6 T6-T7 T7-T8 TS-T9 T9-TlO TlO-T11 Tll-T12 Tl2-Ll

3-5 3-5 2-5 2-5 3-5 2-7 3-8 3-8 3-8 4-14 6-20 6-20

Representative

Angle (dogroo.)

Ono Sldolllo .. 1Bending ('-IIi' rolallon) limits of Rangel Representative (dogroo.) Angl. (dog".')

4 4 4 4 4 5

5 5-7 3-7 5-6 5-6

6

3-8 4-7 4-7 3-10 4-13 5- 10

6 6 9 12 12

6

5 6 5 6 6 6 6 6 6

7 9 8

One Sido Axial Rolalion (Y-Ixl. rolallon) lImli. of Rangl. (dogrees)

Anglo (dogroo.)

14 4-12 5-11 5-11 5-11 4-11 4-11 6-7 3-5 2-3 2-3 2-3

9 8 8 8 8 7 7 6 4 2 2 2

Representative

From White AA III, Panjabi MM, eds. Clinical biomechanics of the spine. 2nd ed. Phi ladelphia: JB Lippincott, 1990: 103.

Axia l ro tati on of the th o racic spine is encouraged in the up per segments beca use of th e mo re tra nsve rse o rienta ti o n of th e face t jo ints. Segmenta l axia l ro tati o n averages 8 to 9° in the upper tho rac ic spine (10)_ Ro tati ona l movements decrease in th e cepha locaudad d irecti o n, a pproximating 2° in th e lower two o r three th o rac ic segments (Ta ble 11 -2) (10)_ ROtati o n is a lso limited by the a nteri o r attac hment of the ribs to th e stern um. The locati o ns of the instantaneo us axes of rota ti o n have been stu d ied by White (10)_ The res ults have been ave raged a nd a re presented in Figure 11 - 18_ Lumbar Spi ne The principa l movements exhibited by th e lumbar spine a nd its individua l jo ints a re ax ial compressio n, ax ia l distracti on, flexion, extension, ax ia l rota tio n, and latera l flexio n (49) _ Ax ial compressio n is the movement that occurs during weig ht bearing in the upr ight posture (49)_ T he a nulus fib rosus an d nucleus pulposus bear the load a nd tra nsmit it to the ve rtebra l

end plates_ T he zyga po ph ysea l joi nts pa rti cipate in the load bea ring if th e o rie ntatio n of th ei r surfaces is other than in the coronal plane_ The jo ints a lso ca n share the load by th e impaction of th e inferio r a rtic ul ar process with the superior a rti cul ar face t o r the la mina of the ve rtebra below w hen the ve rtebra l body is rocked (49)_ T he lo rdosis of th e lumba r spi ne and ante rio r ligame nts pa rticipates in the ax ia l load-bea ri ng mecha nis m. Ax ia l distracti on has bee n stud ied fa r less (49)_ The ca psules of th e zyga po ph ysea l joi nts are the most significant element res isting this motion. Lumbar segmenta l fl exio n and extension are the predomina nt moti o ns in th is region of the spine_ Combi ned sagittal plane mo tion averages 14 to 15° per segment, with mo ti on increasing towa rd the lu mbosac ra l juncti o n (Table 11 -3) (10,24 ). Increasing range of mobi liry in the lower lumba r segments is exhibited by onl y a mino ri ry of pati ents (50) . Flexio n an d ex tension req uire anterio r sagitta l rotati o n aro und the x (co ro n. I)-axis, w hich is located in the posterio r a nulus o f the intervening disc (5 1), alo ng wi th a small a mo unt of fo rwa rd tra nsla tio n_ Sagittal

extension

Laterol bending

rotation

E~F

R~L

R~L

Flexion/

Axia l

Thoracic

FIgUre 11-18 The approximate locations of the instantaneous axes of rotation in the tho racic spine. (From White AA, Panjabi MM. Clillical biomechanics of the spine. 2nd ed. Philadelphia:)8 Lippincott, 1990:105.)

plane translation averages 1 to 3 mm in each direction (25,49,52), whereas anterior sagittal rotation averages 8 to 13" (49). The facet joints guide rotation and resist translat.ion. Segmental lateral flexion averages approximately 6" to each side uniformly throughout the lumbar spine, with the exception of the L5-S1 motion segment (Tab le 11-3). The lumbosacral junction demonstrates hal f of this mo tion (10). Pearcy and Tibrewal found the sa me pattern of latera l flexion, with approximately 10" occurring in the upper three levels, but there was sign ificantly less movement, 6"

and 3" at L4-L5 and L5-S1, respectively (53). Lateral flexion may be acco mpanied by either flexion or extension of the same joint, but extension occurs more frequently and to a greater degree (49). Lumbar lateral flexion involves a complex coup led movement of latera l tilting and rotatory motio n that is open for much debate rega rding the precise biomechanical motion. During lateral bending, some authors describe the " normal " lumbar verteb ral bodies to rOtate toward the concavity, with the spinous process rotating towa rd the convexity (5 1,54,55 ). Unfortunatel y, this may not a lways be the case. Cassidy

>

Limits a nd R epresenta tive Values o f Ra n ges of M o tio n of the Lumbar Spine

Inle .. pa.e

Ll-L2 L2-L3 L3-L4 L4-LS LS-S1

Combined Flllion/Elt.nsion (

o

_ 200, Pinch __ Skin 3.2 N

l6

•

1.2 N

o

- 3.2 N

3.2 N

FIgIre 16-10 Single-unit recordings showing that high-level mechanical stimu lation of paravertebral tissues can effecti ve ly supp ress impulse activity in low-back neurons. This neuron was initially inactive, but afte r pinching the skin receptive field (upper hisrogram) and injecting algogens (for examp le, Brad, 6% NaCI) inro deep paraspinai tissues (responses noc shown ), the ce ll developed an ongoing discharge that was effectively inhibited during and after forceful mechanical stimu lation over the LS-6 facer joinr (3.2 N stimulus, black boxes ). Although noxious (3 .2 N) mechanical input very effectively anenuated unit discharge, less forceful probing had no affect (1.2 N stim ulu s, open box). Exci[atory "breakthrough" (" Brush skin" region of hisrogram) during 3.2 N stimulus-induced inhibition demonstrates that the discharge suppression is neurally mediated. Uni t isolated in lateral lamina II of L5 dorsal horn. (From Gillette, Kramis, and Roberts, unpublished data.)

295

Sympathetic Nervous System Involvement in Low-8ack Pain Because persistent low-back pain is often found to exist in the absence of any detectable, ongoing injury or disease (32), and because other types of chronic pain have been found to be dependent on activity in the sympathetic division of the autOnomic nervous system (31), we have also tested to determine whether low-back neurons respond to electrical stimulation of rhe lumbar sympathetic trunk, located juSt outside the spinal column (10). We found that most (70%) spinal neurons serving the low-back region were indeed acrivated by applying electrical pulses to visceral and somatic afferent and sympathetic efferent axons within the sympathetic trunk, suggesting that activity in these nerve fibers may contribute to

low-back pain (10,11) . This finding in animals is consistent with reports from clinical studies by others indicating that some chronic low-back pain patients benefit from local anesthetic or ablative blocks of the sympathetic trunk ( 10,31,45). This procedure of blocking the sympathetic trunk is not commonly used to diagnose or treat low-back pain, partly because there has been no clear physiologic evidence to suggest that the sympathetic division of the autonomic nervous system has a direct influence on pain from this region.

Our data indicate that at least two types of nerve fibers in the lumbar sympathetic trunk contribute to the activation of these spina l neurons (1O). One type is sensory, being the parent axons

of nociceptor (NOC) and mechanoreceptor (LTM) sensory afferents originating in muscles, ligaments, and other retroperitoneal (visceral) tissues near the spinal co lumn and running in the

sympathetic trunk to finally enter the spinal cord over the dorsal rOOts to directly affect low-back neurons (Figure 15-6) (10,11,16). The convergent input to low-back neurons from visceral nociceptive afferents projecting through the sympathetic chain (Figure 15-6, VISC) cou ld help to explain how pain from pelvic visceral disease is referred

to the low-back region (9,10), a classic example of viscerosomatic convergence (5). The sccond type of activated nerve fiber appears to be sympathetic motor efferent fibers that project out to all tissues, where they act to control blood flow and other processes (10,31). Activity in these sympathetic efferent fibers indirectly trigger activity in other sensoty mechanoreceptive (LTM) and nociceptive (NOC) afferent fibers (10,11,31) that in turn project back into the spinal cord to affect low-back neurons (Figure 15-7). We have also shown that this sympathetic process can be blocked by the alpha-adrenergic antagonist drug phentolamine (Figure 15-7), which mOSt commonly is used to control hypertension or for other diagnostic tests unrelated to pain (10,11). We are investigating whether this drug may provide a safe and harmless means for testing whether the sympathetic nervous system contributes to low-back pain in patients with chronic discomfort (26). The importance of these sympathetically mediated effects is in their capacity to greatly increase the excitatory synaptic drive onto already sensitized low-back neurons to maintain

them in a hyperexcitable state (Figures 15-6 and 15-7). Conceivably, a sympathetically triggered, non nociceptive (LTM) afferent drive could eventually be sufficient to maintain the spinal lowback neuron (Figure 15-7) in a sensitized state, even aftcr peripheral tissues have healed and related nociceptor afferent input has decreased (feature 3) (10,11) .

Neurophysiology of Paraspinal Antinociceptive Systems While studying the response properties of the low-back pain-signaling neurons, we have also examined, to a limited extent, inhibitory phenomena that may be imporram in pain suppression as

opposed to pain production. For example, a subset of the dorsal horn, low-back neutons, from which we have recorded (approximately 20%),

Decending analgesic systems

High-Ievellnoxious) mechanical input

+

+

-::::::::::==:::::=:"':All

t

Injured/inRamed motion·segment

tissues

DISC

t

NOC

figure 15·11 Diagram of the postulated neural circuitry believed to underlie the inhibitory phenomena shown in Figure 15-10. Brief bur noxious mechanical input to paravertebral tissues activates paraspinai nociceptive afferenrs (NOC) that activate spinal inhibito ry inrerneurons both directly (segmentally) and indirectly through a suprasegmemai analgesic loop. The spinally and sup raspinally activated inhibitory imerneuron decreases the electrical excitability and impulse discharging of "already sensitized" low-back (WDR) neurons, leading ro a decrease in perceived low-back pain (.1. LBP). The descending analgesic system can also be independently activated by higher-order brain regions (tOP, open arrow) to produce "context-dependent" antinociception (for example, with placebos). "+" denotes excitatory synapric acrions, and "-" deno tes inhibitory synapric actions.

Decending analgesic sys

t

LTM

t Injured/inflamed motion-segment fi.$U8$

t

NOC

Haurelli-lZ Composire diagram iliusrraring how borh "phasic" (Figure 15-9) and "ronic" (Figure 15-11 ) anrinociceptivc circuits might be coactivated by mechanically forcefu l, chiropractic manipulation (eM) and how these mechanisms could work together to reduce the hyperexcitability of "sensitized" low-back pain transmission neurons. A subsequent decrease in excitability and impulsing across the majority of low-back (WDR) neurons would lead to a subjective decrease in referred low-back pain, that is, an analgesia (J., LBP). "+" denotes excitatory synaptic actions, and "-" denotes inhibitory synaptic actions.

298

The SUl*lxalion COIIIpIex

show complex forms of response suppression to mechanical stimulation o f paravertebral srrucru res (8,10,11). T hese inhibirory res ponses fell into rwo groups, based on the modality of triggeri ng a fferenf input and the duratio n of the inhibito ry

effects produ ced. In some insta nces, brief inh ibition of cellula r discha rge (both ongoing and stimulus-evoked ) could be obta ined by a pplying innocuous mechan ica l stimul ati on ro the sk in

recepti ve field of these cells (Figure 15-8). Interesti ngly, the suppression of neuronal responding

>

Neuro physio logic C orrela tes o f R eferred Low-Back Pain

".... .''.'~\I'.~""""~'.!I"i~'" " , '

.~

Clinical Feature Poorly localized back, hip, and leg pain.

Pollulated Heurel Correlate

Referred pain to arise from deep tissues

Nociceptive input to low-back neurons from

,..1

Spinal neuron "hyperconvergence" and large

unit receptive fields

Spontaneous, ongoing low-back pain

Referred hyperalgesia (stimulus-provoked tenderness)

Radiation of pain

Persistent, referred low-back pain

Pain relief (analgesia) by treatment interventions (for example, CM) and placebos

deep tissues more powerful than skin input Ongoing discharge in many spina l low-back neurons after central sensitizationfLTP Increased responsiveness to mechanical (LTM and NOC) input in the receptive field after centralsensitizationlLTP Unit receptive field expansion over time because of central sensitizationlLTP Recruitment of additional low-back neurons into the active population by: • Release and spread of pro-nociceptive neuroactive substances from afferents • "Unmasking" of latent excitatoty synapses by NOC inputs and sensitizationlLTP • Recruitment of additional low-back neurons by sensitizationILTP and release of diffusible substances SensitizationILTP produces: • Sympathetically mediated increases in LTM and NOC input-refreshes and maintains neuron hyperexcitability • Increased nonnociceptive (LTM) afferent drive maintains neuron hyperexcitability • Loss of inhibitory controls promotes hyperexcitability Recruitment of "tonic" and "phasic" antinociception by: • Coactivation of paraspinal NOC and LTM afferents • CentraUpsychogenic triggers

LTM, mechanoreceptor; NOC, nociceptor; LTP, long-ferm potentiatio n; CM, chiropractic man i pui drug at follow-up 75% success Manipulation = 28%

Stodolny and Chmielewski (1989)

Trelto ..

He.dl.he T-t

Rllulll

Manipulation most effective Manipulation most effective 85%-90% success 80% success 80% success

success initially

A

31

Mig

47% at 2-yr follow-up 75% success

A, Medical Doctor; B, Doctor of Chiropractic; T~(, tension-rypej Mig, migraine Adapted from Vernon HT. Spinal Manipulation and headaches of cervical origin: A review of luerature and presentarion of cases. Manual Medicine 1991; 6:73-9.

normally are relatively "ineffective" ("silent" [11]) in exciting (these) neurons" ([12] p. 72). As such, deep nociceptive inputs are particularly effective in creating ,he mos, significant increase of cutaneous hypersensitivity and an increase in the receptive fields of dorsal medullary horn neurons. In clinical terms, this underlies several important features of deep tissue pain, including its poor localization (explained by multiconvergence on numerous central neurons), hyperalgesia (so-called secondary hyperalgesia), spread of hyperalgesia, and its referral to distant cutaneous regions. All of these phenomena are well-known attributes of myofascial and, in particular, spinal pain syndromes. These are also all important components of myofascial dys-

function and pain referral likely to be operative in headache of cervical origin. Deep pain inputs activate local and, in some cases, distant muscles, presumably in some kind of early protective response. However, it can be presumed that this muscular reactivity contributes to the pain and dysfunction of clinical syndromes involving the neck and jaw articulations. There is a complex neurochemical control of rhese mechanisms that balances inhibitory and excitatory influences within the entire sensorimotor system involved with cephalic and facial pain. All of these mechanisms are consistent with ,he phenomenon of ce1ttral se1tsitizatio1t, which has been demonstrated previously in spinal sys-

18 cervicollllilic IIeadachII

311

Scar/soft 6ssue injury

Substantia gelatinosa &

trigem·inal

Cervical sensory ----1

The Followi ng Symptoms Should Be Asked For and Tests Performed

claudication may become worse in the winter

months and improve in warm weather (20). T his diagnostic feature is one of the differentiating components of vascular from neurogenic TOS, because neurogenic TOS is usually unaffected by climatic conditions.

Diagnosis There are no tests or signs that are pathognomonic of TOS. The diagnosis is by elimination of other syndromes such as carpal tunnel synd rome, cervical spondylosis, cervical disc syndrome, glenohumeral dysfunction syndromes, ulnar nerve entrapment syndromes, Raynaud's disease, space-

occupying diseses of the thoracic outlet such as Pancoast tumor, and cardiac pathologies (see the box on p. 368). Thorough and detailed case history and examination are cardinal feacores of diagnosis (see the box at right). Diagnosis should include the pathomechanics of the lesion such as TOS caused by subluxation of the first rib or TOS caused by myofascia l pain syndrome of the scalene muscles or as neurogenic TOS implicating cervical nerve rOot involvement or vascular TOS implicating involvement of the subclavian vessels.

Provocative Tests The most rehable test, according to Roos (72) and others (6 1,63), is the 3-minute elevated arm stress resr also known in the literature as abducrion and external roration test (AER). In this test the patient's arm is abducted ro 90° with elbow flexed to 90°. The patient then is asked to slowly but steadily open and clinch his or her fist for a full 3 minutes. Thoracic outler patients grad ua ll y develop symptoms of heaviness and fatigue in the involved arm and shou lders, wirh gradual onset of numbness 111 the hand and have to rest the arm for relief of progressive, crescendo distress that becomes intolerable. This test is positive in both neurogenic and vascu lar types of TOS and, when comhined with other objective signs, provides the

• • • • •

Distribution of pain Distribution of paresthesia Weakness or numbness in the arm and hand Aggravation of symptoms with arm elevated Aggravation of symptoms with head and neck movement

• Nocturnal symptoms Pllplal EllIlItIIIiaI

• Vertebral palpation • Ranges of active and passive mobility of the cervical spine • Evaluation of 1st and 2nd rib mobility • Brachial plexus compression supraclavicularly • Shoulder range of movement • Scapular movements • Postural assessment Head position Upper thoracic curve Lateral spinal curves • Elbow range of movement • Ulnar nerve compression at the elbow • Median nerve compression at the wrist • Hand grip strength • Radial and ulnar pulse tests • "Hands-up' test (abduction-external rotation--elevation rest) • Scalene palpation • Scalene relief test Modified from Ribb< EB, Lindgren Sill, Norgren LEH. Clinical diagnosis of thoracic outlet syndrome: Evaluation of patients with cervicobrachial symptoms. Manual Med 1986; 2,82-5.

most reliable tests for diagnosing neurogenic thoracic outlet syndrome (see the box on p. 370). Adson's test is nor cons idered a reliable test,

because pulse obliteration has been found in a large percentage of asymptomatic patients ( I 113); however, an increase in the symptoms with

The 8IMIXItIIIn By.......

370

> ........ ,..

Most Reliable Diagnostic Tests for Neurogenic TOS

• Ipsilateral side of neck • Supraclavicular, over brachial plexus • Infraclavicular

'IIIIIIII..-............

• ImmCdlate pain over braChial plexus • Gradual onset of usual symptoms in neck and arm WI£'., • Triceps (C7)

• Interosseous band muscles (C8, Tt) • Hand grip (C8) Itwll'II'. • Inner fOrearm (C8, Tt) • Ring and smaU fingers, medial side of band • Occasional radial distribution in forearm and thumb EIIIIIIII . . . . . l1li (J H)

• Premarure fatigue and heaviness in involved arm

• Gradual onset of paresthesia in the fingers, spreading through band and forearm • Grimacing and vocal complaints • Crescendo of distress throughout upper extremity

• Sudden, premature dropping of band into lap • Involved band quite slow to recover • Performed with arm abducted to 90° elbow flexed to 90" Adapted &om Uebemoo after ROOI DB. New concepti of thoracic: oudet oyndrome tha. explain etio'osy, symptoms, diapIosis and ....tmen•. Vase Sous 1979; 13:313-21.

var ious positions of the arm is a significant component (73).

Beclrodlagnostlcl Nerve conduction tests are given poor reliability in the literature for definitive diagnosis (1 J ,63,74,75) . According to euetter and Bar-

toszek (I), nerve conduction velocities and latency values are a ll normal unless there is concomitant peripheral neuropathy.

Radography Static radiographs of the cervicothoracic region must be taken to rule out congenital anomalies, although, according to Urschel and Razzuk (36), only 30% of thoracic outlet patients have associated congen ital abnorma lity. Recently, Panegyres et a l. (76) reported that their magnetic resonance imaging (MRI) study showed 70% sensitivity, with 87.5% specificity for deviations and distortions of nerves and blood vessels, and demonstrated the presence of radiographically invisible soft tissue bands in 20 TOS-suggested patients.

FtI1cUonal Evaluation Functional evaluation of biomechanical cervi· cotho racic lesions involves axia l rotation and simultaneous latera l flexion of the cervical spine as first described by Lewit (51) . There is a typ ical tender spot just beneath the clavicle at the manubrium stern i (55) rel ated to torsional stress from the subluxated first rib at the costosternal junction. Lindgren and Leino (48) describe the expiration-inspiration (E-I) test for first rib mobility (Figure 20-3) and report their study of 22 cases of TOS with 100% incidence of hypomobile first rib on the painful side. They further report a 17% recurence of TOS as a result of subluxation of the stump of the resected first rib (78). When the first rib subluxates, usually in an inspiratory position, it moves cranially at the costotransverse joint. When the patient turns the head to the left, the first thoracic vertebra rotates to the left and the transverse process (TP) moves anteriorly. Restriction of cervical rotation away from the side of lesion is most likely caused by the TP of the first th oracic vertebra bumping aga inst the first rib (50). Latera l flexion of the head toward the side of involvement is restricted because the superior position of the offending first rib; hence, restriction and fullness are sensed under the palpating hand (Figu re 20-4).

371 When superior subluxation of the first rib is suggested, all ranges of movement of the first rib should be evaluated. This includes bucket handle and ca liper motion, simi lar to all other rib functions (77). Individually and collectively, the ribs

undergo these two types of motion during respiration (79). The bucket handle motion is tested while latera lly flexing the head toward the contact position over the nonarticulating tubercle of the first rib (Figure 20-3). Normally the first rib depresses at the end point of its passive range of motion and a small accessory passive joint range (joint play) motion can be elicited. Abnormal inspiratory subluxation may be attributable to sca lene hypertonicity. Ca liper motion is tested by using the head as a lever to magnify this small movement (Figure 20-5). The thumb is placed on the nonarticulating tubercle of the rib, and the head is rotated away from the side. The normal movement is a slight anterior springing of the transverse process and the rib (end joint feel), giving no resistance to the palpating thumb.

Management fIIII't 20-3 The expiration and inspiration (£-1) movement of the first rib is palpated in relation to the clavicle. The right and lefr sides are compared.

The initial management of patients with thoracic outlet syndrome should always be conservative. Early operations should only be considered if vascular ischemia, serious embolic complication, or rapidly advancing denervarions and muscle wasting are the prominent features .

...... 20-4 Rotarion and lateral flexion of the cervical

RIIrt m-t; Evaluation of caliper rype of motion of

spine is restricted if the first rib is suhluxated superiorly. There will be fullness and loss of inferior end joinr spring of the first rib, as noted by (he

the first rib. When normally functioning, there wi ll he a small range of end movement at the extreme range of cervical rotation. The head is used as a lever to magnify this small accessory joint play.

palpating hand.

372 Surgical management has been severely criticized in the literature, especially when large studies show that only 24% of patients with thoracic outlet syndrome actually requite surgery (63,71,73,80,81). A well-informed patient is always a more compliant patient; hence, explanation of the pathomechanical state should always be given. This alleviates the patient's often ill-defined symptom picture and provides a more receptive patient to carry out instructions. These should include postural advice and reeducation, and avoidance

of carrying a heavy shoulder bag or handbag. Sleeping postures also must be evaluated, and the use of COntour pillow to support the cervical curve should be considered. Postural reeducation and correction of poor body mechanics are essential in the management of TOS. Round-shouldered or slouched postures often aggravate TOS and are the typical patient presentations. These postures not only place undue stress on the scalene and pectoralis muscles but also compromise the neural foramina and posterior zygapophyseal joints at the cervicothocacie junction. Prime concerns 3re correction of all associated

biomechanical dysfuncrions: the cervical spine, the first rib, both at the costovertebral and manubriocostal junction, the sternoclavicular and acromioclavicular joints, and the shoulder complex, with special attention paid to the scapulothoracic function. When the scalene muscles are involved, the stretching techniques advocated by Travell (66) are very effective in relieving acute spasms as well as relieving chronic, painful myofascial pain syndromes. Because the sternocleidomastoid (SCM) muscle is also an important part of the myotatic unit for accessory inspiration, it likely will be involved along with the scalene. If the SCM is involved, it may be the cause of temporal and occipital headache, a TOS patient's frequent complaint. Satellite trigger points (TPs) may develop in muscles along the radiating pain pattern of the scalene. Both pectorals are often involved in radiating chest pain (pseudoangina). Satellite TPs in

the long head of the triceps correspond with posterior arm pain and shoulder pain. Secondary TPs commonly develop in the brachioradialis, extensor carpi radialis, and extensor digitorum mus-

cles, resulting in pain associated with thumb and wrist movements. The scalene-relief test identifies scalene involvement with relief of the symptoms as compared with true neurogenic TOS, where various arm positions aggravate the symptoms

(Figure 20-6). Daily passive streching on the scalene muscles at home is critical to recovery (Figure 20-7). Chiropractors frequently use direct pressure over trigger points (ischemic compression), first discussed by Nimmo (82), writing in the }ollmal of the National Chiropractic Association in 1957. He believed that pressure applied to the belly of a contracted muscle interrupts the pain-spasm-pain cycle, and relaxation of the spastic muscle follows. Ischemic compression is widely used by chiropractors as well as stretching in the treatment

of trigger points (83). Chiropractic adjusrive techniques for the cervicorhoracic area, including corrections for first rib subluxations, clavicular subluxations, scapu-

lothoracic, and glenohumeral dysfunctions, have been well described by Szaraz (84); Kirk, Lawrence, and Valvo (85); Gatterman and Panzer (86), and mOSt recently by Peterson and Bergmann (79). Once the inferior component of the lesion is corrected, particular attention should also be paid to the cervical component of the lesion, especially because the scalene muscles intimately influence cervical dynamics, as has been classically described by Grice (87).

Conclusion The thoracic outlet syndrome is a challenging clinical entity. Careful history taking and thorough physical examination, including in-depth biomechanical evaluation of the cervicothoracic area, provides the practitioner with important

diagnostic clues to arrive at a solid clinical impression to undertake conservative therapeutic interventions.

20

The TIIoracIc Outlet ~: Iftt RIll SUbluxation . . . . .

373

A

B

~ 2IHI The scalene-relief teSt helps to identify the source of referred pain from active trigger points in the scalene muscles. A, This is the starring position and can be combined with Roos's test. B, Raising the shoulder elevates the clavicle, relieving pressure on the neurovascular bundle and shortening the scalene muscles. CJ As the shoulder is swung forward, the scapula is pcoccacred and the clavicle moves forward and upward to fully relieve clavicular pressure on the thoracic outler structures.

c

374

B

c A ~ 20-7

Side-bending stretching exe rcises are perfo rmed bilaterall y and dail y. A. Th e hand on the

side to be stretched is anchored under the buttock. B, To stretch th e scalenus posterior, the face is turned toward the direction of pull. C, The face looks forward to stretch the scalenus medius. D, The face is turn ed away from the directi on of the pu ll to stretch th e scalenus anterior.

D

375

ReI.'IIICeI I. Cuener AC. Bartoszek OM. The thoracic outler syndrome: Controversies, overdiagnosis, Qvertreatment and recommendations (or management. Muscle Nerve 1989; 1M10-19. 2. Brash Jc, Jamieson ES, ws. Cunningham's text book of anatomy. 7th ed. London: Oxford UniverSity Press, 1937. 3. Davies DV, Davies F, eds. Gray's anatomy. 3Jrd ed. london: Longmans, 1962. 4. Cooper A. On exostosis. In: Cooper SB, Cooper A, Travers B, cds. Surgical essays: American physician. 1st ed.

Philadelphia: James Webster, 1821. 5. Coore H. ExostOSIS of the left uansverse process of the seventh cervical vertebra surrounded by blood vessels and nerves: Successful removal. Lancet 1861; 1:360. 6. Todd TW. The relauonship of the thoracic operculum conslderarion In reference to the 3n3(Omy of cervical nbs of surgical Importance. J Anat Physiol 1911; 45:293-304. 7. Todd TW. The vascular symptoms 10 'cervical nb.' Lancet 1912, 2,362-5. 8. Halstead WS. An expenmental study of circumscribed dilation of an artery immedi:uely distal to partially occludmg band and its bearing on the dilation of the subclavian artery observed in certain cases of cervical rib. J Exp Med 1916; 24,271. 9. Adson AW, Coffey JR. Cervical nb: a method of anterior approach for relief of symptoms by division of the scalenus amicus. Ann Surg 1927; 85:839. 10. Adson AW. Surgical rreatment for symptoms produced by cervical nbs and the scalenus anticus muscle. Surg Gynecol Ob"" 1947; 85,687-700. 1 I. Roos DB. Congemtal anomalies associated with thoracic ourletsyndrome. AmJ Surg 1976; 132:771. 12. Telford ED, Monershead S. Pressure at the cervicobrachiallunction; An operative and anatomical study. J Bone Joom Surg 1948; 308,249. 13. Wnght IS. The neurovascular syndrome produced by hyperabductlon of the arm. Am Heart J 1945; 29: l. 14. Falconer MA, Weddell C. Costoclavicular compression of the subclavian artery and vein. Lancet 1943; 2;539. 15. Peer RM, Hendricksen JD, Anderson TP, Martin CM. Thoracic outlet syndrome: evaluation of a therapeutic exercise program. Proc Mayo Clin 1956; 31:281-7. 16. Lee R, Farquarson T, Domleo S. Subluxation und blockicrung der ersten nppe: eine ursache fur das "thoracic outlet syndrome." Manuelle Medlzin 1993; 31: 126-7. 17. Lindgren K-A, Leino E. Subluxation of the first rib: A possible thor3cic outlet syndrome mechanism. Arch Phys Med Rehab,l 1988; 6%92-5. 18. Pang D. Wesscl HB. Thoracic outlet syndrome. Neurosurgery 1988, 22, I 05-21. 19. Oastler EH, Anson BJ. Surgical anatomy of the subclavian artery and Its branches. Surg Cynecol Obstet 1959; 1082,149-74.

20. Sunderland S. Disrurbances of brachial plexus origm associated with unusual anatomical arrangements in the cervico-brachial region: The choracic outlet syndrome. In: Nerves and nerve inluries. New York: Churchill LivingS[Qne, 1978: Chapter 66.901-19. 21. Williams AF. The role of the 1st rib in the scalenus anterior syndrome. J Bone Joint Surg J 952; 34B:200-3. 22. Brinrnall ES, Lyndman OR, Van Allen MW. Costoclavicular compression associated with cervical rib. Ann Surg 1956; 144,921-6. 23. Lord JW, Rosati LM. Thoracic outlet syndromes. Clin Symp 1971,23,3-32. 24. Pollack EW. Surgical anatomy of the thoracic ourlet syndrome. Surg Cynccol Obstet 1980; 150:97-103. 25. Todd TW. The descent of the shoulder after birth: Its sig~ nificance in the production of pressure-symptoms on the lower brachial trunk. Anar Anar 1912; 41:385-97. 26. Nelson RM, Davis RW. Thoracic outlet compression syndrome. Ann Thorac Surg 1969; 8;437-5 J. 27. Raaf J. Surgery for cervical rib and scalenus amicus syndrome. JAMA 1955; 157,219-23. 28. Clein LJ. The droopy shoulder syndrome. Can Med Assoc 1976; 114,343-4. 29. Swift TR, Nicholas FT. The droopy shoulder syndrome. Neurology 1984; 34,212-14. 30. Beyer JA~ Wright IS. The hyperabduction syndrome: With special reference to its relationship [Q Raynaud's syndrome. Circulation 1951; 4: 161-72. 31. Lord JW, Stone PW. Pectoralis minor tenotomy and anterior scalenotomy with special reference to the hyperabduction syndrome and "effort thrombosis" of the subclavian vein. Clrculation 1956; 13:537-42. 32. McCleery RS, et al. Subclavius and anterior scalene muscle compression as a cause of intermittent obstruction of the subclavian vein. Ann Surg 1951; 133;588-602. 33. Rosati, LM, Lord JW. Neurovascular compression syndromes of the shoulder girdle. New York: Grune & Stratton, 1961:8()""91. 34. Daube JR. Rucksack paralysis. JAMA 1969; 208,2447-52. 35. Hanes RW. Movements of the fi.rst rib. J Anat 1946; 80,94-100. 36. Urschel HC Jr, Razzuk MA. Thoracic outlet syndrome. Surg Annu 1973; 5,229-63. 37. Ener LE. Osseous abnormalities of the thoracic cage seen 10 four thousand consecutive chest photoroentgenograms. AJR 1944; 51 :359-63. 38. Steiner HA. Roentgenologic manifestations and clinical symptoms of rib abnormalities. Radiology 1943; 40,175-8. 39. Huu N, Vallee B, Person H, er .11. Anatomical bases of uansaxillary resection of the first rib. Anat Clin 1984; 4,221-33. 40. Turek S. Orthopedic principles and their application. 3rd ed. Philadelphia: JB Lippincott, 1977:799.

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TIle SUl*Ixatlon Syndl'IIIMI

41. Rayan GM. Lower trunk brachial plexus compression neuropathy due to cervica l rib in young athletes. Am J Spons Med 1988; 16( 1),77-9.

42. Naffziger He. The scalen us syndrome. Surg Crnccol Obsrcr 1937; 64:119-26. 43. Oschsner A, Gage M, DcBakcy M. Scalenus amicus (Naffziger) syndrome. Am J Surg 1935; 28:669-95. 44. Clagen OT. Research and prosearch. J Thora c Cardiovasc Surg 1962; 44,153-66. 45. Barg:u WL, Marcus RE, Inleman FP. Late thoracic outlet syndrome secondary fa pseudoarthrosis of the clavicle. J Trauma 1984; 24,857-9. 46. Connolly J F, Dehne R. Delayed thoracic ourler syndrome from clavicular nonunion: Management by morseling. Ncbr Med J 1986; 71,303-6. 47. Ganga har DM , Flogaires T. Rerrosternal dislocation of the clavicle producing thoracic outlet syndrome. J Trauma 1978; 18,369-72. 48. Lindgren K·A, Leino E. Subluxarion of the firsr rib: A possible thoracic ourtCt syndrome mechanism. Arch Ph ys Med Rehabil 1988; 6%92-5. 49. Lindgren K·A , Leino E, Manninen H. Ci neradiography of the hypomo bile firsr rib. Arch Phys Med Rehabil 1989; 70,408-9 . SO. Lindgren K·A, Leino E, Hakala M, Hamberg]. Cervica l spine rorarion and lateral fl ex ion combincd morion in thc examination of the thoracic ourtct. Arch Phys M~d Reha· bil 1990; 7 1,343-4. 5 t. Lewit K. Impaircd joint function and entrapment syn· drome. Manuctlc Medizin 1978; 16:45-8. 52. Bland JH. Cervical spine syndromes. J Mu sc uloskcl Med 1986; 3( 11),23-41. 53. Kirkaldy· Willis \'(rH. Pathology and pathogenesis of low back pain. Chaprer 5. In: Kirkaldy-Willis WH, Burron C V, eds. Managing low back pain. 3rd ed. New York: Churchill Livingstone, 1983:49-79. 54. Philips H , G rieve GP: The thoracic outlet syndrome. Chapter 35. In: Grieve GP, cd. Modern manual therap), of the vertebral col umn. Edinburgh: Churchill Livingstone 1986,359-69. 55. Lewir K. Clinical aspects of disturbed fun crion of rhe locomotor system. Chapter 7. In: Lewir K. Manipulative therapy in rehabilitation of the locomotor system. 2nd cd. Oxford: Burterworrh· Heinemann, 199 1:231-67. 56. Rashbaum RF. Multidisciplinary spinal rehabilitati o n: management by o bjectives. C hapter 35. In: Hochschuler ST, COt ler HB, Guyer RD, cds. Rehabilitation of the spine, science and practice. St. Louis: Mosby, 1993,425-33. 57. Hargberg M, Wegman DH. Prevelence rates and odds ratios of shoulder·neck diseases in different occu pational groups. Br J Ind Med 1987;44 (9),602- 10. 58. Satow A, Taniguchi S. The development of a moror performance method for the measurement of pain. Ergonomics 1989; 32(3),307- 16.

59. Amano M , Umeda G, Nakajima H , Yarsuki K. Characteristics of work actions of shoe manufacfUring assembly line workers and a cross-sectional factor*Conrrol stud)' on occupational cervicobrachial disorders. Sangro 19aku 1988; 30,3- 12. 60. Dellon AL. The results of supraclavicular brachial plexus neurolysis (without rib resection ) in management of pOSt· traumatic "thoracic outlet syndrome." J Recon srr MicroSUIS 1993; 9( 1), 11-1 7. 6 1. Razi OM, Wassel HD. Traffic accident induced thomcic ourler syndrome; decompression without rib resection, correcrion of associated recurrent thoracic aneurysm. 1m Surs 1993; 78(1),25-7. 62. Sanders RJ, Pearce WHo The treatment of thoracic outlet syndrome: A comparison of different operarions. J Vasc Surg 1989; 10(6),626-34. 63. Sallstrom j, Schmidt H. Cervicobrachial disorders in cerrain occupations, with special reference [0 compression in the thoracic outler. Am J Ind Med 1984;

6045-52. 64. Ribbe EB, Lindgren SHS, Norgren LEH. Clinical diagnosis of thoracic oudet syndrome: Evaluation of patients with cervicobrachial sym ptoms. Manual Medicine 1986; 2,82-5. 65. Conn j. Thoracic o ueler synd rome. Surg Clin North Am 1974; 54,155-60. 66. Travell JG , Simons DG. M yofascial pain and dysfunction: the trigger point manual. Baltimore: Williams & Wilkins, 1983. 67. Gilliatt RW, LeQuesne PN, Logue V, Sumner AJ. Wasting of hand associat'ed with a cervica l rib or band. J Neural Neurosurg I'sychiatr)' 1970; 33:615-26. 68. Carrott RE, Hurst LC. The rel:ttionship of thoracic outlet syndrome and carpal runnel syndrome. Clin Orr hop 1982; 164,149-53. 69. Asbury AK, Dyck pJ , Johnson AC, et al. Coping with carpal runnel syndrome. Patient Ca re 1985; 19:76-90. 70. Urchcl H C Jr. Dorsa l sy mpathectom)' a nd management of thoracic outlet syndrome with video-assisted thoracic surgelY (VATS ). Ann Thomc Surg 1993,56 (3),7 17-20. 71. Riddel DH, Smith BM. Thoracic and vascular aspects of thoracic outlet syndromc. Clin Onhop 1986; 207:31-6. 72. Roos D8. New concepts of thoracic ourler syndrome thar explain etiology, symptoms, diagnosis :md treatment. Vasc Surg 1979; 13:3 13-21. 73. Stallworth JM, Horne JB. Diagnosis and management of thoracic ourlet syndrome. Arch Surg 1984; I J 9: 1149-5 1. 74. Daube JR. Nerve conducrion studies in the thoracic ourler syndrome. Neurology 1975; 25:347. 75. Ryding E, Ribbe E, Rosen I, Norgren L. A neurophysiological investigarion in thoracic oudet syndrome. Acta ChirScand 1985; 151:327-31. 76. Paneg),res ilK, Moore N, Gibson R, et at. Thoracic outlet syndrome and magnetic resonance imaging. Brain 1993; 1 16(P, 4 ),823-4 1.

377 77. Fligg B. Spmal biomechanics. CMCC, 1989. Personal communication. 78. Lindgren K-A, Lemo E, Lepantaio M. et al. Recurrent thoracic outlet syndrome after first rib resection. Arch Phys Me
83. Ganerman MI, Gae DR. Muscle and myofascial pam syndromes. In: Ganerman MI, ed. Chiropractic management of spine related disorders. Baltimore: Williams & Wilkins, 1990. 84. Szaraz Z. Compendium of chiropractic technique. CMCC 1984. 85. Kirk CR, Lawrence OJ. Valvo NL, eds. States manual of spinal, pelvic and extravertebral technic. 2nd ed. NCC 1985. 86. Ganerman MI, Panzer OM. Disorders of the thoracic spine. In: Ganerman MI, ed. Chiropractic management of spme related disorders. Baltimore: Williams & Wilkins, 1990. 87. Grice AS. Scalenus amicus syndrome: DiagnOSis and chiropractic adlustive procedure. JCCA 1977; 5:35-7. 88. Liebcnson CS. Thoracic outlet syndrome: Diagnosis and conservative man3gement. J Manipul3tive Physiol Ther 1988; II: 493-499.

• Thoracic and Costovertebral es n Adrian Grice

Costovertebral subluxation syndromes, scoliosis, coupled motion After reading this chapter you should be able to answer the following questions:

11111II1II #1:

Why do the traditional movement descriptions of flexion, extension, lateral flexion, and rotation need to be modified to describe segmental spinal motion?

QUIIIIIII #2:

How does altered motion in thoracic motion segments accompanying aging lead to degenerative changes in the thoracic spine?

Q 1II1II13:

What is the clinical significance of the transition area of spinous process rotation that accompanies lateral flexion?

379

C

omparatively little is known about the neurologic, biomechanical, and physiologic relationships of this region of the spine. This is peculiar when one realizes that the thoracic spine houses the sympathetic nervous system and spinal dysfunction has been implicated in the development of somatovisceral reflex dysfunction, vis-

ceral dysfunction, and pain. What is known about thoracic physiology and biomechanics has been largely extrapolated from known functions of the cervical and lumbar spines. It would appear that our knowledge of spinal function has been driven largely by the need to understand the causes and treatment of spinal pain, and therefore, the lumbar spine, and secondarily the cervical spine, has captured mOSt of OUf attention.

Much of the literature relating to the thoracic spine is devoted to pathologic conditions and conditions that, with a few exceptions, have little

to do with the clinical problems that are seen on a daily basis by the chiropractic clinician. Clinical experience, however, demonstrates

non physiologic, responses of viscera, including cardiovascular and respiratory systems and the locomotor system as a whole. The relationship may be through neurologic reflex changes or through direct biomechanical muscular function such as, for example, diaphragm contraction in respiratory change producing direct biomechanical effects on the rib cage and spine. Diagnostic evaluation of any segment or region of the thoracic spinal or rib cage therefore should consider:

1. The

locomotor

system

as

a

whole,

as

expressed in movemenc dynamics

2. Static body posture and our adaptation to graviry 3. The vertebral column and its function as an organ system 4. The cardiovascular and respiratory systems 5 . The visceral elements and reflex responses 6. The cervical spine and its postural reflex regulation and direct muscle attachments 7. The lumbar spine, its postural regulation, and direct muscle attachments

that pain syndromes and disorders of the thoracic spine and rib cage that do manifest themselves are quite frightening to the patient and produce

8. The functional interaction of the thoracic spine and rib cage

anxiety about internal diseases that mayor may

Clinically Relevant Anatomy

not be relevant. Pain, pathology, and degenerative changes in this region of the spine have been shown to relate to postural changes, including scoliosis and kyphosis, autonomic and visceral dysfunction or pathologic condition, aberrant spinal static or dynamic function, or aberrant costovertebral function (1-3). Aberrant static and dynamic function is related to dysfunction of the soft tissues, that is, the ligaments, muscles, and

discs. Joint function is regulated by sensorimotor reflex feedback loops. The sensory proprioceptive system gets its main input from skin, muscles, lig-

aments, blood vessels, and fascia and has been estimated to form 65% to 75% of the input; the special senses and viscera form the rest of the input. Thoracic spinal dysfunction therefore can be related to the overall neurologic regulation of the body's static and dynamic, physiologic and

The dorsal vertebrae are intermediate

In

size

between the cervical and lumbar vertebrae, and they increase in size from above downward, a

structural accommodation thought to relate to the increased demands of weight bearing (4). The rypical thoracic vertebra is so named because of the nature of rib attachments. The second to the eighth thoracics are considered rypical and contain two pairs of demifacets, one on the superior

posterolateral aspect of the body and one on the inferior aspect directly below, which form the articulation with the head of the ribs on each side. Viewed from the superior aspect, the typical vertebra shows a heart-shaped body with relative equal anterior-to-posterior dimensions, and the

spinal canal is round (Figure 21-1). The left side of the vertebral body sometimes has an impres-

380

TIle SUIIIuxatIan Sy........

fIIUN 21-1

fIIIre 21-2 Lateral view of typical th oracic vertebra,

1987.)

wedge-shaped vertebral body. (From Clemente. Anatomy, A regional atlas of the human body. 3rd ed. Urban and Schwarzenberg, 1987.)

Superior view of typica l thoracic vertebra . (From Clemente. Anatomy: A regional atlas of the human body. 3rd ed. Urban and Schwarzenberg,

sion formed by the aorta, which lies along the vertebral bodies and discs. From the lateral perspective, the vertebral body is slightly thicker on the posterior than the anterior. This vertebral shape is functional in forming the primary normal thoracic kyphosis. The superior and inferior disc end plates should appear parallel on radiographs. The pedicles are directed backward from the body, and the inferior intevertebral notches are large in size and deeper than in other regions of the spine, resulting in small but adeq uate intervertebral foramins that are circular in form (Figure 21-2). The laminae are broad and thick, and they overlap one another like tiles on a roof. They give rise

to

the

inferior

and

superior

articu lar

processes. The superior articular processes each have an ova l hyaline cartilage-
Chiropractic College).

454

The SUbluxation Syndi'Oll18l

pelvic ring, cushioning the slight amount of observed physiologic movement. They developed a method of monitoring this movement using palpation with the back of the hand to challenge end feel of the sacroiliac joints (Figure 24-2).

Jomt may be forced into a new pOSItion where ridge and depression are no longer complementary. They note that this abnormal joint position may be regarded as a blocked joint (manipulable subluxation) . It is thought that the resultant restriction of movement or aberrant motion

Sacroiliac Subluxation Sacroil iac subluxation may take the form of simple joint locking or this may be accompanied by compensatory hypermobility in adjacent joints, especially in menstruating and pregnant females . Vleem ing et aJ. (17) state that it is theoretically possible that with abnormal loading a sacroiliac

that occurs from a shift in the normal axis of rotation then produces a sacroiliac subluxation

syndrome. The characteristics of a sacroiliac subluxation have been described by Turek (18 ) as ligamentous stretching sufficient enough to permit the ilium to slip on the sacrum as an irregular prominence on one articular surface

becomes wedged on another prominence of the other articular surface. He states that this is consistent with surface irregularities that have been noted on examination of the sacroi liac joint su rfaces.

Clinical Considerations The clinical findings associated with sacroiliac subluxation syndrome are described by Turek as intense muscle spasm accompanied

by severe pain

(18). The cause of sacroiliac subluxation is often indicated by the patient'S history. Frequently they describe a fall on the buttocks or a lifting injury that involved torsional stress . Stepping off of a cu rb or twisting such as getting out of bed have been reported (14).

Pain Pattern The pain of sacroiliac syndrome is typically located over the ipsi lateral buttock, dull in character, and made worse on sitting. It occasionally

Ag1I'824-2 The screening method urilized by Giller used rhe dorsum of the hand ro challenge end feel.

may extend down the lateral and posterior calf, occasionally as far as the ankle, foot, and toes (Figure 24-3). Sensory changes rarely occur bur occasionally take the form of paresthesias in the ipsilateral lower extremity. Pain referred from the sacroiliac joints is experienced in the posterior dermatomal areas of LS, 51, and 52, radiating over the sacrum and into the buttocks. Pain referral from the anterior ligaments radiates into the anterior derm.tomal areas of L2 and L3, particularly into the thigh region immediately below the

455

• XX XX Xx

•••

F11P'124-8 Pain parrern of a patient with a right sacroiliac syndrome. (- , aching; x, burning; -, numbness.) (From Catterman MI. Chiropractic management of spine related disorders. Baltimore: Williams & Wilkins, 1990.)

groin (19,20) . Pain from a hypermobile sacroiliac joinr also may be experienced in the ipsilateral hip because of contraction of the ipsilateral piriformis muscle, which originates at the sacrum and ilium (Figure 24-4) . A hype rmobile joint generally stabilizes within 3 to 6 weeks when abnormal motion is restricted

by a trochanteric support

bandage (Figure 24-5). Localized tenderness is produced on palpation of the subluxated sacroil-

iac joint. The patient also may exhibit a li mping gait to minimize pain on weight bearing.

Although localized pain and tenderness have demonstrated higher interrater reliability than other palpatory indicarors such as motion pa lpation, misalignment palpation, and muscle tensio n

palpation (21), pain alone cannOt be considered the major criteria for diagnosis of subluxations. Nonmanipulable subluxations in which force-

456

xx xx xx x x x

Piriformis syndrome. Trigger poin(~ (.) located near the belly and insertion of the piriformis muscle refer pain (x) in a characterisric partern. (From Calterman M l. Chiropractic management 0/ spine related disorders. Baltimo re: Wiilliams & Wilkins, 1990.)

f1111'124-4

FIgIre 24-5 A hypermobile joint can be stabilIzed with a right elastic rrochanreric bandage. The sacroiliac joint is generally stabilized within 3 to 6 weeks with this form of continuous stabilization. (From Gatterman. Chiropractic management of spme related disorders. Baltimore: Willtams & Wt/kilts , 1990.)

Pelvic Compression Pain, especially in irritated or inflamed joints, can indicate sacroiliac involvement when compression

ful manipulation is contraindicated may exhibit pain and tenderness from hypermobility and, III extreme cases, instability (see Chapter 8).

Tests lor Sacroiliac Dysfunction Sacroiliac dysfunction can be detected by a number of orthopedic tests. As with other areas of the spine, however, the manipulable subluxation is best detected through motion palpation. Specific rests detect sacroiliac involvement, bur give no indication as to whether manipulation is indicated.

is applied to the pelvis. Pressure can be applied to the iliac crests with the patient lying on the side or supine (Figures 24-6). Pain provoked in the sacroiliac regions indicates a positive test in any of these positions, but does not differentiate the exact nature of the sacroi liac problem or give an indication of the appropriate treatment.

FigII'8 of FoIr (FABRE) Test The acronym FABRE stands for flexion, abduction, external roration, and extension, which forms a figure of four when the thigh is passively put through these movements (Figure 24·7). Pain can be localized to either the ipsilateral hip or sacroiliac joints by this rest.

24 Sacrollac SUI*Ixatlon Syndrome

457

B A

Flgll'824-8 Co mpression applied to the il iac cresr(s) with the patient side lying (A) or supine (8 ) may produce pain in irritated o r inflamed sacro ili ac joints. Sacroiliac involvement is also suspected jf pain is prod uced whe n sacroiliac joint fun ction is provoked by press ure a ppl ied to se para te th e ili ac crests (C).

c

458

A

B

Rgure 24-1 A, Joint play ar rhe hip can be resred by moving the knee through an arc beginning with the

knee and thigh flexed, adducred, and internally rotated, and B, ending with the thigh flexed, abducted, and externally rotated. C, Pain in the sacroiliac joinr can be differentiated from hip pain by the Patrick Fabere test. (Figure C From Catterman. Chiropractic management of spine related disorders. Baltimore: Williams & Wilkins, 1990.)

24

A!111'124-8

Sacroiliac Subluxation Syndrome

Normally the straight leg can be raised to Q

90° without discomfort. Pain at 45 Of, less particularly, of the electric shock type that radiates into the feet, the back, or the opposite side indicates nonspecific irri tation of the sciatic nerve or root. Pain produced from 70° [0 90° and localized to the sacroiliac joint is more indicative of a sac roi liac lesion. (From Gattenllon. Chiropractic management of spine related disorders. Baltimore: WilUams & \Vilkins, 1990.)

A!111'124-8

Hyperextension of the ipsilateral thigh

produces pain with lesions of the sacroiliac joint. (From Cotterman. Chiropractic management of spine related disorders. Baltimore: Williams &- Wilkins, /990.)

459

460 Straight Leg RaIse (SUI, Lasegues' SIgn) Raising the straight leg is used in detecting sciatic nerve irritation and also can indicate sacroiliac involvement when pain is localized to the ipsilat-

eral articulation. Sciatic involvement is generally pain producing when the straight leg is raised to less than 45°, whereas the rest becomes positive for sacroi liac dysfunction when raised between 70° and 90° (Figure 24-8).

ThIgh Hyperextension (Yeomam's Test) Pain localized to the sacroiliac joint on hyperextension of the ipsilateral thigh indicares a test positive for sacroiliac involvement bur nOt the nature of the problem. Performed with the patient in the prone position, extension of the thigh is often noticeably restricted in the sa me

side as the pain with a sacroi liac subluxation (Figure 24-9).

RadOlll'aphIc AndIngs The sacroiliac joints are difficult to visualize radiographically and are best viewed with the beam passing posterior to anterior. Plain fi lm radiographs cannor detect a manipulable subluxation, a lthough several marking systems have been used to detect pelvic misalignment. Pelvic instability can be demonstrated by radiokinetic tests that stress the sacroi liac joints and the symphysis pubis (Figure 24-11, A, B, C). The patient stands

fIgIre 24-10

E

Pelvic instability can be demonstrated by

radiok inetic reSts that stress the sacroiliac joints and

the symphysis pubis. In A, the patient is standing with the weight evenly distributed for the neutral PA view of [he symphysis pubis. In B, the patient is standing on [he lef[ leg while [he right leg hangs free. Note [he superior sheer of the left pubic bone. In C, the patient is standing on the right leg while the left leg hangs free. The pubic bones are now aligned. (From Catterman. Chiropractic management of spine related disorders. Baltimore: Williams & Wilkins, 1990.)

c

461

• ..--r; ) J

Sitting

B

- I Lying

Rg&re 24-11

Relative changes observed in functional

leg length durmg change from supine to sitting position

when a simple sacroiliac subluxation/fixation is present. Leg A rcprcsenrs the side of the PI ilium (flexion malposlfion) and leg B the AS ilium (extension malposition). Because of the relative anterior

displacement of the acterabululll resulting from the flexed ilium (and opposite for rhe extended ilium), the

leg that is functionally shorr reverses as rhe patient sirs and the hip Jomt is flexed ro 90°, (From Cotterman. Chiropractic management of spme related dIsorders. BaIt/more: \'(ItlJimm

& \,(/ilkms, 1990. )

on rwo blocks approximarely 6 inches from the Aoor. The blocks are alternately removed to allow one leg to hang free (22). A neutral view with

inclusion of the sacroiliac joints in all views is recommended. Instability of the sacroiliac joints is confirmed by separation of the symphysis pubis in the vertical plane (23).

Mechanics 01 Sacroiliac Subluxation and Dysfunction Because motion of the sacroiliac joint occurs largely in the sagittal plane (24) (Aexion and extension) (25), it is not surprising that rhe plane of blocked sacroiliac joint motion is generally nexion or extension with accompanying malposition in this plane. The ilium, fixed in a flexed position in relation to the sacrum, has been termed a PI (posteroinferior) ilium, wirh rhe pos-

462 terior superior iliac spine (PSIS) as the reference point (26). The AS (anterosuperior) ilium describes an ilium fixed in an extended position. When the ilium flexes, the following occurs (26): 1. PSIS moves posteriorly and interiorly 2. ASIS (anterior superior iliac spine) and ipsilateral pubis move superiorly 3. Acetabulum moves anteriorly, laterally, and slightly superiorly, causing functional shortening of the leg 4. Sacrum moves relatively anteriorly and interiM orly on the ipsilateral side (25) Opposite movements occur during iliac exten-

sion. Among the findings mentioned is the movement of the acetabulum. When the pelvis becomes locked in a torqued position with one ilium in extension and the other in flexion, the relative position of the acetabulae may be different enough to result in measurable difference in functional leg length (Figure 24-11). It is important to nOte that this phenomenon is quite distinct from anatomic leg length discrepancy (26) and is generally correctable with appropriate sacroiliac manipulation. Common postural features of funcrional and anatomic leg length discrepancies are unleveling of the greater rrochanters and/or iliac crests while standing. Alterations 10 the static alignment of anatomic landmarks may also assist in the diagnosis and classification of sacroiliac subluxation (25). Table 24-1 gives examples of common palpatory characteristics that differentiate a flexion malposition (PI ilium) from an extension malposition (AS ilium) (25,26).

Common palpatory characteristics which differentiate a flexion malposition (PI ilium) from an extension malposition AS ilium) ~

.

~

.

~.

"

;~

,.,-.

r....

.;."

..\-

PI

AS

1. Prominent and inferior PSIS 2. Superior positioned ASIS 3. Functionally shorter leg supine, prone and standing 4. Functionally longer leg sitting (see Figure 24-11)

1. Less prominent and superior PSIS 2. inferior positioned ASIS 3. Functionally longer leg supine, prone and standing 4. Functionally

5. Lower iliac

5. Higher iliac

crest (standing)

1

shorter leg sitting

(see Figure 24-11) crest (standing)

sacrum and ilium while the patient raises and

lowers each leg (Figure 24-12). Although these standing motion tests are widely used, intraexam-

palparory examination of comparative sacroiliac

iner reliability has been shown to exceed interexaminer reliability, and the validity of these procedures has yet to be fully demonstrated (28). Palpation of overall sacroiliac movement may be complicated by aberrant motion that may occur because of a shift of the axis of rotation caused by subluxation. Another teS! for sacroiliac pathomechanics is the "sacral push." The doctor sits behind the seated patient with thumbs spanning the space between the PSIS and the sacral base (across the sacroiliac joint). As the patient extends the torso, the sacral base glides anteriorly and can be followed by the doctor's thumbs (25). Motion in the oblique coronal plane can be monitored by having the patient flex and laterally bend to each side as if to tie their shoe. Restricted motion in this plane is moS! easily restored by using a sacral

motion by palpating the relative motion between

contact.

A survey of current texts used in chiropractic

education shows a variety of dynamic examination procedures that are used in addition to the aforementioned static tests (19,20,25,27,28). These dynamic procedures are directed at the assessment of sacroiliac function. Perhaps the most widely used of these tests is the standing

24 S8C1'OIIIIc Slauxallon SyID'ome

B

A

f1111'124-12 A, Relative morion of (he left sacroili ac joint is palpated with the rhumb placed over the second sacral tubercle and the other ove r the PSIS. B, With

normal motion, the PSIS moves downwa rd I to 2 em as the leg is raised. C, If the joint is fixed the PSIS does nor move downward.

c

463

464

~ 24-14

The patient with a sacra l rotational fixation is positioned in side postu re, with the side of fixation involvement placed down . The hand contacts the upper portion of the sacrum, and with a scooping

motion the thrust is delivered anteriorly, away from (he

locked joint. detect abnormal resistance to specific gliding movements or the presence of increased pain ro identify potential sacroiliac dysfunction (25).

figure 24-18 Relative motion in the oblique corona l plane can be monitored by having the patient flex and laterally bend (0 each side as if to tie their shoe .

The preceding tests are examples of tests that evaluate sacroiliac range and qua lity of motion. Another dynamic palpatory procedure used in evaluation of sacroi liac joint function is joint play

exam ination. Joint play motions are completely passive in nature, that is, they acc produced entirely by the doctor without active movement of the patient. These movements can be produced with the patient sitting, prone, or side-lying a nd are thoroughly described in current chiropractic procedural texts (25). Joint play tests seek to

Treatment 01 Sacroiliac Subluxation Syndrome The treatment of choice for sacroiliac subluxation syndrome is specific manipulative therapy (Figure 24-14) directed at the sacroi liac articulations (14,19,20,25) . Prospective clinical studies have shown a successfu l response in more than 90% of patients receiving daily manipulation over a 2- ro 3-week period for chronic disabling sacroiliac syndrome (19). Mobilizing and stretching techniques, as well as exercises, also can be helpful in the management of this condition (29).

References I. Smith OG, Langworthy SM, Paxson Me. Modernized

chiropractic. Vol 2. Ceda r Rapids, Iowa: L1wrcnce Press, 1906,217-73.

24 Sacrollac SUbluXallon Syndrome

" - " 24-16 The side pos[Ure technique for manipulation of a right superior sacroiliac joint fixation has the doctOr's stabil izing hand rracrioning the patient's supe rior shou lde r while the thrusting hand contactS the affected ilium. The manipulative thrust is directed through the ilium, down the thigh and the long axis of the patient's flexed leg. The patient's superior leg is tcactioned with the doctor's inferior thigh, and a body drop is simultaneously instituted as the thrust is delivered. 2. Palmer 8J. An exposition of old moves. 2nd ed. Davenport, Iowa: Palmer School of Chiropractic, t 91 1: 121-2. 3. Gregory AA. Spina l treatment: auxiliary methods of frear· ment. 2nd ed. Ok lahoma City: Palmer-Gregory College, 1912,545-9. 4. Carver W. Carver's chiropractic analysis of chiropractic principles as applied ro pathology, reiafOlogy, symptoma· (Ology, and diagnosis. Vol I. 3rd ed. Oklahoma Ciry: Paul Parr, 1921. S. Forester AL. Principles and practices of spinal adjustment. Chicago: National School of Chiropracric, 19I5:374-S. 6. Mixter WJ, Barr JS. Rupture of the intervertebral disk with involvement of the of spinal canal. N Engl J Mcd 1934; 211,220. 7. Weisl H. The movement of the sacro· iliac joinr. Acta Anat 1955; 2],80-89. 8. Colachis SC Jr., Warden SC, Bechral CO, Strohm BR. Movement of the sacroiliac joint in the adult ma le: a pre· liminary report. Arch Phys Med Rehabil 1963; 44:490-8. 9. Frigerio NA, Srowe RR, Howe JW. Movement of the sacro-iliac joint. Clin Orthop 1974; 100:370-7. 10. Bowen V, Cassidy JD. Macrocopic and microcopic anaromy of the sacro-iliac joint from embryonic life until the eight decade. Spine 198 I; 6:620-8.

o

465

II. Maclennan AH. The role of the hormone relaxin in human reproduction and pelvic girdle relaxation. Scand J RheumaroI 199 1;S88:7- 1S. 12. Kapandji IA. The physiology of the joints: the trunk and vertebral column. Vol 3. New York: Churchill Living· stone, 1974:S9. 13. Wilder DG, Pope MG, Frymoyer JW. The functiona l tOpography of the sacroi liac joint. Spine 1980; 5:S7S-9. 14. Ganerman M: Chiropractic management of spine related disorders. Baltimore: Williams & Wi lkins, 1990:111-12. 15. Brunstrum S. Clinica l kinesiology. 3rd ed. Philadelphia, FA Davis, 1979:11. 16. Gillet H, Liekans M. Belgium chiropractic research notes. 4th cd. Huntingron Beach, California: Motion Palpation Institute, 1981 :9. 17. Vleeming A, Volkers ACW, Snijders Cj. Stoeckerr R. Relation between form and function in the sacroi liac joint. Part II. Biomechanical aspects. Spine 1990: 15(2): 133-S. 18. Turek SL: Orthopedics principles and their application . 3rd ed. Philadelphia: JB Lippincott, 1977: 1469. 19. Cassidy JD, Mierau DR. In : Haldeman S, ed. Principles and practice of chiropractic. 2nd ed. San Mateo, California: Applewn and Lange, 1992:211-24. 20. Kirkaldy Willis WH , Burton CV. Managing low back pain. 3rd cd. New York: Churchi ll Livingstone, 1992,123-6. 2 1. Keating JC, Bergmann TF, Jacobs GE, Finer BA, Larson K. Interexaminer rel iability of eight evaluative dimensions of lumbar segmental abnorma lity. J Manipulative Physiol The< 1990; 13(8),463-70. 22. Ballinger PN. Merrill's atlas of radiographic positions and radiographic procedures. Vol I. 5th ed. St. Louis: Mosby,247. 23. Dihlman W. Diagnostic radiology of the sacroi li ac joints. Chicago: Year Book, 1980:12-16. 24. White AA, Paniabi MM. Clin ical biomechan ics of the spine. 2nd ed. San Francisco: JB Lippincott, 1990,1 12-15. 25. Bergmann TF, Peterson DH, Lawrence DJ. Chiropractic technique. New York: Churchill Livingstone,

1993A77-98. 26. Panzer DM. In: Gatterman MI. Chirop ractic management of spine related disorders. Baltimore: Williams & Wilkins, 1990,278-8 1. 27. Wa lters PJ. In: Plaugher G, ed. Textbook of clinical chiropractic. Ba ltimore: Wi lliams & Wilkins, 1993: 153-61. 28. Herzog W, Read LJ, Conway PJW, Shaw LD, McEwen Me. Reliability of motion palpation procedures w detect sacroiliac joint fixations. J Manipulative Physiol Ther 1989; 12(2),86-92. 29. Don Tigny RL. Mechanics & treatment of the sacroi liac joint. J Manual Manipulative Ther 1993; It 1):3- 12.3; 1(1),3- 12.

• Coccygeal Subluxation Syndrome John P. Mrozek

KeyWDrds

Coccydynia, pelvic diaphragm, anal verge

After reading this chapter you should be able to answer the following questions:

question #1

What is the correlation between coccygeal angulation and coccydynia?

Questloo #2

What is the procedure for reduction of a coccygeal subluxation?

25

COCCygeal SUbluXation Syndrome

P

ain in the coccygeal area is referred to as coccydynia in the relevant literature. Coccydynia was first described by Simpson in 1861 (1). He noted that when injury to the coccyx or surrounding tissue occurred, contraction of the muscles attached to the coccyx would elicit the characteristic pain of coccydynia (2) . The term, denoting a painful coccyx, indicates a symptom rather than a pathologic diagnosis. Hence one should determine the ca use of this condition when the taking the history. Coccydynia is described as occurring as a single clinical entity or in combination with other painful presentations such as low-back pain . The diagnosis in most instances relies a great deal on the elicitation of local pain and tenderness. The refractory nature of this complaint suggests a greater role for possible inclusion of psychogenic overlay in the differential diagnosis. The history and physical examination, however, show the local nature of this complaint. Local well-demarcated areas of pain are not generally associated with pain of psychogenic origin (3) .

Anatomic Considerations A number of structures are potentially implicated when coccydynia is encountered. The hard and soft tissues that make up the pelvis and lumbar spine constitute the clinical area of concern. Referred coccydynia can be the result of exrrasegmental reference from a lumbar disc lesion (3,4). Evaluation of the lumbar spine structures and appreciation of the relevant neuroanatomy arc necessary to ensure a proper

assessment. A diagnostic clue for the consideration of referred pain wou ld be found in the history. Although referred pain may persist in a number of body positions, local coccydyn ia mOSt often is present as the result of direct pressure as encountered by sirting (3) . The coccyx consists of usually four rudimentary vertebrae. Variations in segments of one less

467

or one morc also exist. The shape of the coccyx was seen as beaklike by early observers. The term coccyx is derived from the Greek word fo r cuckoo. The three inferior coccygeal segments often fuse in middle age. In old age the first coccygeal segment often fuses to the sacrum (5). The pelvic diaphragm and its immediate surround constitute the major muscular considerations when dea ling w ith the coccyx. For genera l purposes the pelvic diaphragm is formed by the levator ani and coccygeus muscles (Figures 25-1 and 25-2)

Levator AnI The levaror ani muscles form the posterior two thirds of the pelvic floor, and the anterior one third is formed by the perineal membrane, which bridges the pubic ram i inferior to the anterior fibers of the levator ani muscles. The levaror ani is penetrated by the ana l canal, and the perinea l membrane is penetrated by the urethra in the man and by the urethra and vagina in the woman . Origin: pelvic surface of the body of the pubis to the ischial spine Insertion : the central perineal tendon, the wall of the anal cana l, the anococcygeal ligament, the coccyx Action : raise the pelvic floor. This action assists the abdominal muscles in compressing the abdominal contents. This is important in coughing, vomiting, urinating, and trunk fixation during strong movements of the upper limbs such as lifting. Innervarion : third and fourth sacral nerves and the inferior rectal nerve

Coccygeus This muscle forms the posterior and smaller part of the pelvic diaphragm. Origin: the ischial spine Insertion: lateral aspect of the fifth sacral vertebra and coccyx

468

Sacrospinous ligament

Coccygeus muscle

Sacrococcygeal joint - - -....._-,-"" 1st intercoccygeal joint ----'~,,-';ili

r---:-;------

Levator ani muscle

Anterior socrococcygeal ligamen Anococcygeol raphe Anal opening Perineal body

FIgIre 21H

This illustration represenrs the relevant muscles and ligaments rhar pertain to the sacrococcygeal area

from the posterior view.

(From Duckworth, Friesen L.)

Action: supports the coccyx and pulls it forward after defecation and childbirth Innervation : fourth and fifth sacral nerves (5) The g luteus maximus a lso attaches to the coccyx. This anatomic reality must be taken into consideration when planning treatment of the coccygeal area. The gluteus maximus is the chief extensor of the thigh. The nerve supply is the inferior g luteal nerve. Both the innervation and

action must be assessed when formulating a treatment regimen. The relevant ligaments associated with the coccyx include the sacrotuberous, the sacrospinous, and the anococcygeal. In addition to their coccygeal attachment, the sacrotuberous and sacrospinous ligaments he lp resist sacra l nexion (between the innom inarcs) caused

by

gravita-

tional effects of erect posture. Sandoz refers to

lateral sacrococcygeal lig< ~~,G.~_-+

____

Coccygeus muscle Sacrospinous ligament

'-;-7T~--_ 4th sacral nerve Sacrotuberous ligament

5th sacral nerve Intercornual ligament

levator ani muscle Anococcygeal raphe

Perineal body

RIIN 25-2

External anal sphincter muscle

This illusrrarion represenrs rhe relevant muscles and ligamenrs rhat pertain ro rhe sacrococcygeal area

from rhc anrerior view. (From Duckworth, Friesen L.)

25

Coccygeal SUbluxation Syndrome

these structures as "check ligaments" of nuration (6). These two ligaments reinforce and add strength to the sacroiliac joint capsule (7) . The anococcygeal ligament is the median fibrous intersection of components of [he levator ani muscle. It is located between the anal canal and the coccyx (5) (Figures 25-1, 25-2). The actual configuration of the coccyx, particularly as seen on the lateral radiograph, shows an interesting pattern of variation. Observations vary from slight forward angu lation to partial dislocation that accompanies sharp forward angulation. These are radiographic interpretations and do not correlate necessarily with a

painful presentation. As indicated earlier, there is some variation in the fusion pattern of the coccygeal segments. Where coccygeal segmental movement is preserved, the first intercoccygeal joint represents the fulcrum of movements of the coccyx (1) . The greater the angulation, the greater the likelihood of developmental instability of the joint. Insult that stretches the articular and periarticular structures of intercoccygeal joint contributes largely to coccydynia .

Diagnosis Coccygeal area pain can present in a variety of ways. The general considerations include acute, chronic, loca l, and referred. As reported earlier, the low back has been cited as a locus of pain referral to the coccygeal area. Postacchini and Massobrio (1) noted a high incidence of back pain in patients with idiopathic coccydynia compared with the general population (1,8 ). Malbohan et al. (8) reported that the pelvic diaphragm was clinically involved in nearly a ll of the 1500 cases of low-back pain that they studied. Assessment of the pelvic diaphragm was recommended in cases of recurrent low-back pain. The symptoms and signs of acute and chronic coccydynia include pain with sitting, bowel movements, and intercourse. Point tenderness at the tip of the coccyx should be assessed.

469

Many aspects of coccygea l area pain can be evaluated on ly by internal rectal examination (9). The rectal approach allows for direct palpation of the coccyx and pelvic diaphragm . Tenderness of the levator ani and coccygeus ca n be ascertained with digital pressure applied to the areas latera l to the coccyx. Palpating the coccyx by contacting it with a lubricated gloved index finger internally and thumb pressure applied externa ll y a llows for assessment of relative mobility. This method allows the examiner to assess for coccygea l angulation. The coccyx should be moved anteriorly and posteriorly and side to side. Patient positio n for the rectal examination sho uld be prone with abdominal suppOrt or the lateral decubitus (Figure 25-3) . The histOry is integral to the formulation of a proper diagnosis. The historica l workup involves questions related to a number of conditions, including gastrointestinal, genitourinary, gynecologic, musculoskeletal, and psychologic ab normalities. The answers to inquiries regarding rhese a reas give clues to the understanding of the patient's complaint. For rhe chiropractor, the sacroi liac joint is high on the index of suspicion for referred pain. This joint mUSt be assessed and treated if indicated. A good general rule wou ld involve the reproduction of pain. That is, if the examiner can recreate the pain of the involved area, then the examiner can infer that the source of the complaint has been found. In this case, if joint challenge of the sacroi liac area reproduces the coccydynia, then the examiner can be reasonably sure that the source of the pain resides in the sacroi liac joint.

lreabllent Allowing that referred pain has been ruled Ollt, the treatment of choice for coccydynia is by direct means. Following the description outlined in the diagnosis section of this chapter, the gloved index or middle finger is inserted beyond the ana l verge

470

The SUbluXadoo 8YIIlll'Ol11l8

Pubic symphysis

r---'''''-..----+-+ - - - - - - 1 - + ;--------

~~~~'it~~~~:::=:~~~~==~~= :

Bladder Urethra

External anal sphincter Internal anal sphincter

Rectum External anal sphincter

Sacrococcygeal joint 1sf in,tercoccygeol joint

Infernal anal sphincter

FIgIre 25-3 The method of digital examination of the sacro·coccygeal area as seen from the latera l view.

(From

Duckworth. Friesen L.)

with the palmar aspect applied against the coccyx. The free hand is applied against rhe sacrum externally. Assuming an anterior or flexion subluxation

of the coccyx, pressure is app lied to rhe coccyx in a slowly increasing increments for approximately 40 seconds. If tOlerated, the practitioner can apply slowly increasing pressure to the sacrum to augment (he treatment.

The practitioner must always be mindful of [he patient'S reaction ro this pressure. This can best be monitOred by having the patient turn the head to the side if in the prone position. In this position the practitioner can view the facial response and observe for the customary reaction to pain. One must be careful not to proceed beyond the patient's tOlerance. While applying pressure, the practitioner can slowly sweep the contact finger from side to side of the coccyx, assessing the soft tissues in the area . This digital cOntact with the soft tissues can reduce tension in the pelvic diaphragm.

The application of digital pressure to the coccyx and the slow sweeping of the soft tissues should be repeated a second time while within the anal canal. The practitioner should then remove the gloved finger from the cana l and observe for blood, feca l, or other matter. The results of this procedure should be duly noted in the chart. In general, uncomplicated coccydynia should respond quickly to this type of treatment. Two or three treatments over a period of 7 to 10 days are usually sufficient to achieve alleviation of symptoms (10).

Acknowledgments The excellent drawings are provided by the skilled hand of J. W. A. Duckworth, MD . His contribution is greatly appreciated .

References I. Posracchini F, Massobrio M. Idiopathic coccygodynia: analysis of fifty-one cases and a radiographic study of the normal coccyx. J Bone Joint Surg 1983; 65A: 1 11 6-24.

25 COCCy..... SUI*IxItIon Syndrome 2. DiGiovanna EL, SchlOWltz S. An osteopathic approach to diagnosis and (tc-atment. New York: JB Lippincott, 1991,452-6. 3. Cyriax J. Textbook of onhopaedic medicine. Vol I. Diag· nasis of soft tissue lesions. 5th ed. London: Balliere, Tindall & Cass

C3psules, articular, 19,20 Central convergence-projection, 284-287, 28S·287, 294, 297 Central facilitation, SO

effecrs, 109-111 chlropracric reflex techniques, 109·111

CentT31 neuronal plastlclry, referred pain, 28S-287, 288· 294

function central processing

In

control of,

261-264

Centr31 sensitization, SO Cerebral dysfuncrion theory,340· 352

hypothalomlC conrrol, 261-263 Axoplasmic transport, aberrant, subluxation, 183

Cerebrospinal fluid flow, altered, subluxation,184 Cervical ll1jury, of spinc, �table, 9 Cervical jOlllt

B

subluxotlon, 132-134, Il I

Arthropathie�. mflamll1