Rectal prolapse: diagnosis and clinical management

Donato F. Altomare,Filippo Pucciani (Eds)

Rectal Prolapse Diagnosis and Clinical Management

Editors Donato F. Altomare Department of Emergency and Organ Transplantation General Surgery and Liver Transplantation Unit University of Bari Bari, Italy Filippo Pucciani Department of Medical and Surgical Critical Care University of Florence Florence, Italy

Library of Congress Control Number: 2007933189

ISBN 978-88-470-0683-6 Springer Milan Berlin Heidelberg New York e-ISBN 978-88-470-0684-3 Springer is part of Springer Science+Business Media springer.com © Springer-Verlag Italia 2008

This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the Italian Copyright Law in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the Italian Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. Cover layout: Simona Colombo, Milan, Italy Typesetting: Compostudio, Cernusco s/N (Milan), Italy Printing: Arti Grafiche Nidasio, Assago, Italy Printed in Italy Springer-Verlag Italia S.r.l., Via Decembrio 28, I-20137 Milan, Italy

Foreword by John Nicholls

Rectal Prolapse: Diagnosis and Clinical Management is a unique publication. It is a multiauthor work edited by experts who have drawn together opinions by professionals highly recognised in the field. The book deals with a common condition in all its aspects – from aetiology and pathophysiology to treatment by the numerous available methods. The incidence of rectal prolapse will increase with the ageing population. In the young, functional defecation disorders sometimes associated with prolapse are frequently seen in colorectal practice and are an important cause of morbidity. For these reasons, the wide-ranging and detailed account of the subject contained within its pages makes the book particularly valuable. The contents give extensive information on the causes of prolapse and its investigation and treatment. In doing so, the editors have included contributors from home and abroad who have national and international standing. The concentrated experience that this offers is of the highest order. The book deals comprehensively with the various forms of prolapse, including external prolapse, rectal intussusception and genital prolapse. Our understanding of the pathophysiology of rectal prolapse has advanced in the last 10–20 years due to the application of more sophisticated methods of neurophysiological assessment and of technical developments in imaging. The chapters on aetiology and investigation set out in detail the present position regarding the value of these advancements in clinical practice. The interface between rectal and genital prolapse is dealt with, as is the relationship of rectal prolapse to other anorectal symptoms such as incontinence and evacuation difficulty. The various abdominal and perineal procedures, including laparoscopic rectopexy, are described in separate chapters. Besides the classic operations, new treatments such as the STARR and EXPRESS procedures are dealt with, and their indications are considered in relation to the clinical presentation and the various other options. There is discussion on the relative merits of abdominal and perineal surgical approaches. Function following surgery receives considerable attention, and the difficult problems that may be posed by recurrence after surgery are dealt with. Nonsurgical treatment and rehabilitation are also described. There are chapters outlining best practice and a treatment algorithm that, being evidence based, set a standard of management guiding the reader through the decision-making process. The book is beautifully laid out. The illustrations are exceptional. They include high-quality operative colour photographs and line drawings that demonstrate clearly the relevant stages of the procedure in question. Rectal Prolapse: Diagnosis and Clinical Management gives a detailed and authoritative statement of current best practice through a wide-ranging account of all aspects of the condition. There is no other book on the subject that does so in such depth. The extensive bibliography will be a valuable resource to all practitioners involved in managing rectal prolapse, as well as to research workers in the field of functional bowel disease. The book should appeal not only to surgeons but also to gastroenterologists, physiologists and radiologists – whether in training or in established consultant practice. London, September 2007

Prof. John Nicholls, MD Emeritus Consultant Surgeon St. Mark’s Hospital Professor of Colorectal Surgery Imperial College, London

Foreword by Floriano Marchetti by Stanley M. Goldberg

The treatment of rectal prolapse encompasses hundreds of different operations, and despite being known and studied for millennia, the subject still creates controversy. Never, since its first recorded description in the Eber papyrus of 1500 BC has so much attention and research, so much passion and discussion, been focused on this problem. Yet, the pathophysiologic bases of this condition remain elusive; the superiority of one technique over another unclear. The surgical landscape for rectal prolapse has recently expanded to include new treatments such as the STARR and EXPRESS procedures. The apparent effectiveness of these new techniques has allowed greater insight into the understanding of the role of intussusception in the development of rectal procidentia. Conversely, these procedures have raised new questions and stirred an ongoing global controversy. If these operations are as effective as claimed, should we then operate on all patients presenting with obstructed defecation and internal intussusception? Will this prevent the development of rectal procidentia? Will the resulting rearranged pelvic anatomy prevent prolapse recurrence? Alternatively, will the same pathophysiologic mechanism that generated the prolapse in the first place, and which may not have been addressed, lead to recurrence? The answers are clearly not yet available, and long-term follow-up will hopefully assist us in the near future to attain those answers. Furthermore, technical details, indications, and outcomes of these new techniques are not widely understood. Clearly, no significant comparison can be made if uniformity of indications, techniques, and goals is missing. No publication so far has extensively treated these issues; therefore, the majority of surgeons and almost all nonsurgical physicians involved in the treatment of rectal prolapse have no comprehensive and effective knowledge of the new operations. The richness and variety of choices for treating rectal prolapse may become confusing, and controversy may be paralyzing when dealing with a problem about which our understanding remains somewhat obscure. These are some reasons many surgeons felt the need for one articulate and comprehensive volume that presented an all-inclusive understanding of the pathophysiology of rectal prolapse and state-ofthe-art surgical treatment for it. There is, in fact, the obvious necessity to understand new techniques and perhaps the need to weed out old procedures that offer nothing other than a historical perspective in the understanding and treatment of this condition. This daunting task was taken up by the editors and contributing authors of this book and implemented in an authoritative and concise fashion. Rectal Prolapse: Diagnosis and Clinical Management offers a body of information encompassing any aspect of pathophysiology, diagnosis, and treatment of rectal prolapse. It is a meticulous, exhaustive review of what is established, what is new, and what we should know about rectal prolapse and its treatment. Rectal prolapse is routinely treated in colorectal surgery textbooks as a separate entity without any deep, comprehensive discussion of the pathophysiologic antecedents that lead to its development. This book details the current understanding of prolapse mechanisms as well as the long process of anatomic and physiologic changes and symptoms that lead to rectal procidentia and fecal incontinence. Several different treatment procedures – surgical and nonsurgical – are listed and technically described, as are their results. Each procedure is treated in separate, logically laid-out chapters, with constant reference to the pathophysiological processes of rectal prolapse. Rarely, if ever, in a textbook have obstructed defecation, intussusception, and rectal prolapse been addressed together in a comprehensive and coordinated fashion in the attempt to understand the inter-

Foreword

relations that tie these three entities together. The editors and authors of this book have successfully achieved that goal and provided this missing link. The layout is beautiful, and the illustrations are precise to the smallest detail. The pool of contributors includes some of the most authoritative experts on the subject in the world, and whereas colorectal surgeons everywhere will benefit the most from this book, it is a valuable resource to all health care professionals who deal with such patients. Miami, October 2007

Prof. Floriano Marchetti MD Assistant Professor of Clinical Surgery Division of Colon and Rectal Surgery DeWitt Daughtry Family Department of Surgery Miller School of Medicine University of Miami Miami, FL, USA Prof. Stanley M. Goldberg MD, FACS Clinical Professor of Surgery Division of Colon and Rectal Surgery Department of Surgery University of Minnesota Minneapolis, MN, USA

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Contents

SECTION I Rectal Prolapse: Anatomy, Pathophysiology and Imaging 1 Perineum: Functional Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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R. De Caro, A. Porzionato, V. Macchi

2 Rectal Prolapse: Pathophysiology

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

13

F. Pucciani

3 Functional Imaging in Rectal Prolapse

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

21

V.L. Piloni, A. Bazzocchi, R. Golfieri

4 An Overview of Neurophysiologic Tests in Rectal Prolapse

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33

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41

SECTION II Internal Prolapse 6 Rehabilitative Treatment for Internal Rectal Prolapse . . . . . . . . . . . . . . . . . . . . . . . . . . . .

53

C. Ratto

5 Classification of Internal and External Rectal Prolapse F. Pomerri, P.C. Muzzio

F. Pucciani

7 Treatment of Internal Rectal Prolapse by Rectopexy . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

57

H.M. Paterson, D.C.C. Bartolo

8 Treatment of Rectal Intussusception by Internal Delorme Procedure

......

63

9 The STARR Procedure for Internal Rectal Prolapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

71

E. Ganio, I. Giani P.-A. Lehur, G. Meurette, M. La Torre

10 The EXPRESS Procedure for Internal Rectal Prolapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

81

P. Giordano, N.S. Williams

SECTION III External Prolapse 11 Perineal Approach to External Rectal Prolapse: The Delorme Procedure

..

89

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

97

G.A. Binda, A. Serventi

12 Perineal Approach to External Rectal Prolapse: The Altemeier Procedure

D.F. Altomare, M. Rinaldi

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Contents

13 Surgery for Rectal Prolapse: Functional Outcome from the Perineal Approach – An Overview

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

103

S.D. Wexner, A. Khanna

14 Surgical Treatment of Rectal Prolapse: Rectopexy without Mesh

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107

15 Mesh Rectopexy: The Wells Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

113

R. Bergamaschi, M. Fealk A.P. Zbar

16 Rectopexy with Mesh According to the Ripstein Technique . . . . . . . . . . . . . . . . . . .

121

V. Sohn, S.R. Steele, A. Mellgren

17 Rectopexy with Mesh: The Orr-Loygue Technique

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131

A. Infantino, R. Bellomo, D. Del Ciampo

18 Rectopexy According to Frykman-Goldberg Technique

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139

G.G. Delaini, G. Colucci

19 Laparoscopic Ventral Rectocolpopexy for Complex Rectogenital Prolapse

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145

A. D’Hoore, F. Penninckx

20 Management of Rectal Prolapse: The Role of Laparoscopic Approaches

..

153

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157

D.R. Metcalf, A.J. Senagore

21 Surgery for Rectal Prolapse: Functional Outcome from the Abdominal Approach - An Overview L. Pa°hlman, U. Karlbom

22 The Management of Recurrent Rectal Prolapse

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169

R. Madoff, J.W. Ogilvie Jr., S.R. Steele

23 Surgery for Rectal Prolapse: General Criteria for the Selection of the Best Treatment

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177

G. Romano, F. Bianco, L. Caggiano

24 Management of Associated Pelvic Dysfunctions: External Rectal Prolapse and Faecal Incontinence

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183

G. Dodi, L. Amadio

25 Management of Associated Pelvic Dysfunctions: External Rectal Prolapse and Genital Prolapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 M. Cervigni, F. Natale, A. Padoa

26 Management Guidelines for Full-thickness Rectal Prolapse . . . . . . . . . . . . . . . . . . . .

201

A.P. Zbar, H. Nguyen

Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Contributors

Donato F. Altomare Department of Emergency and Organ Transplantation University of Bari Bari, Italy Luca Amadio Department of Surgery University of Padua Padua, Italy David C.C. Bartolo Western General Hospital Edinburgh, United Kingdom Alberto Bazzocchi Department of Radiology Pelvic Floor Imaging Centre Radiologia Golfieri Malpighi-S-Orsola Hospital Bologna, Italy Roberto Bellomo Department of Surgery Civil Hospital San Vito al Tagliamento (PN), Italy Roberto Bergamaschi Department of Surgery Lehigh Valley Hospital Penn State University Campus Allentown, PA, USA Francesco Bianco Department of Surgery I “S.G. Moscati” Hospital Avellino, Italy Gian Andrea Binda Department of Surgery Galliera Hospital Genoa, Italy

Luisa Caggiano Department of Surgery I “S.G. Moscati” Hospital Avellino, Italy Mauro Cervigni Department of Urogynecology S. Carlo - IDI Hospital Rome, Italy Gianluca Colucci Department of Surgery and Gastroenterology University of Verona Verona, Italy Gian Gaetano Delaini Department of Surgery and Gastroenterology University of Verona Verona, Italy Raffaele De Caro Department of Human Anatomy and Physiology School of Medicine University of Padua Padua, Italy Domenico Del Ciampo Department of Surgery Civil Hospital San Vito al Tagliamento (PN), Italy Giuseppe Dodi Department of Surgery University of Padua Padua, Italy Andre D’Hoore Department of Abdominal Surgery University Hospital Gasthuisberg Leuven, Belgium

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Contributors

Michael Fealk Department of Surgery Lehigh Valley Hospital Allentown, PA, USA Ezio Ganio Colorectal Eporediensis Centre Department of Colorectal Surgery Monza, Italy Iacopo Giani Department of Medical and Surgical Care University of Florence Florence, Italy Pasquale Giordano Department of Surgery Whipps Cross University Hospital London, United Kingdom Rita Golfieri Department of Radiology Pelvic Floor Imaging Centre Radiologia Golfieri Malpighi-S-Orsola Hospital Bologna, Italy Aldo Infantino Department of Surgery Civil Hospital San Vito al Tagliamento (PN), Italy Urban Karlbom Department of Surgery University Hospital Uppsala, Sweden Amit Khanna Department of Colorectal Surgery Cleveland Clinic Florida Weston, FL, USA Marco La Torre Department of Digestive and Endocrine Surgery Hôtel-Dieu University Hospital of Nantes Nantes, France Paul-Antoine Lehur Department of Digestive and Endocrine Surgery Hôtel-Dieu University Hospital of Nantes Nantes, France

Veronica Macchi Department of Human Anatomy and Physiology School of Medicine University of Padua Padua, Italy Robert D. Madoff Department of Surgery Division of Colon and Rectal Surgery University of Minnesota Minneapolis, MN,USA Anders Mellgren Division of Colon and Rectal Surgery University of Minnesota Minneapolis, MN, USA Dan R. Metcalf Spectrum Health Ferguson Clinic Grand Rapids, MI, USA Guillaume Meurette Department of Digestive and Endocrine Surgery Hôtel-Dieu University Hospital of Nantes Nantes, France Pier Carlo Muzzio IRCCS-Istituto Oncologico Veneto and Department of Medical Diagnostic Sciences and Special Therapies, Radiology University Hospital Padua, Italy Franca Natale Department of Urogynecology S. Carlo - IDI Hospital Rome, Italy Hung Nguyen Department of Surgery Launceston General Hospital Launceston, TAS, Australia James W. Ogilvie Jr. Department of Surgery Division of Colon and Rectal Surgery University of Minnesota Minneapolis, MN,USA Anna Padoa Department of Obstetrics and Gynecology Assaf Harofe Medical Center Zrifin, Israel

Contributors

Lars Påhlman Department of Surgery University Hospital Uppsala, Sweden

Giovanni Romano Department of Surgery I “S.G. Moscati” Hospital Avellino, Italy

Hugh M. Paterson Department of Colorectal Surgery Western General Hospital Edinburgh, United Kingdom

Anthony J. Senagore Spectrum Health Ferguson Clinic Grand Rapids, MI, USA

Freddy Penninckx Department of Abdominal Surgery University Hospital Gasthuisberg Leuven, Belgium

Alberto Serventi Department of Surgery Galliera Hospital Genoa, Italy

Vittorio L. Piloni Department of Radiology Pelvic Floor Imaging Centre Radiologia Golfieri Malpighi-S-Orsola Hospital Bologna, Italy

Vance Sohn Department of Surgery Madigan Army Medical Center Tacoma, WA, USA

Fabio Pomerri Department of Medical Diagnostic Sciences and Special Therapies, Radiology University Hospital Padua, Italy Andrea Porzionato Department of Human Anatomy and Physiology School of Medicine University of Padua Padua, Italy Filippo Pucciani Department of Medical and Surgical Critical Care University of Florence Florence, Italy Carlo Ratto Department of Surgical Sciences Division of Digestive Surgery Catholic University Rome, Italy Marcella Rinaldi Department of Emergency and Organ Transplantation University of Bari Bari, Italy

Scott R. Steele Department of Surgery Madigan Army Medical Center Tacoma, WA, USA Steven D. Wexner Department of Colorectal Surgery Ohio State University and Department of Surgery University of South Florida College of Medicine Cleveland Clinic Florida Weston, FL, USA Norman S. Williams Centre for Academic Surgery The Royal London Hospital London, United Kingdom Andrew P. Zbar School of Clinical of Human Life Sciences University of Tasmania Launceston, TAS, Australia

XI

SECTION I Rectal Prolapse: Anatomy, Pathophysiology and Imaging

1

Perineum: Functional Anatomy Raffaele De Caro, Andrea Porzionato, Veronica Macchi

Introduction

Pelvic Diaphragm

The perineum is the complex of tissues between the peritoneum and the skin that closes the pelvis inferiorly. The surface projection of the perineum and the form of the skin covering vary considerably depending on the position of the thighs: they are reduced when the tighs are adducted, whereas they widen when the tighs are flexed and abducted. The perineum is diamond-shaped, bounded by four lines: two from the pubic symphysis to the ischial tuberosities, and two from the ischial tuberosities to the coccyx. In the female, it is crossed anteriorly by the urethra and the vagina and posteriorly by the rectum; in the male, it is crossed anteriorly by the urethra and posteriorly by the rectum. Thus, in the female, the skin of the perineum is reduced compared with that in the male. Anatomical structures between the perineum and skin are constituted by muscles and fasciae, which are located in three planes: (1) the pelvic diaphragm, (2) the urogenital diaphragm, and (3) the superficial plane of the perineum.

The pelvic diaphragm is constituted by two laminar muscles, the levator ani and ischiococcygeus muscles, which – arising from the pelvic walls – are attached to the opposite pelvic walls (Figs. 1 and 2). Their fibres are primarily directed backwards to the coccyx and the rectum. The fasciae investing the muscles are the superior and inferior fasciae of the pelvic diaphragm. The two levator ani are similar to a funnel shape with the apex at the level of the puborectal sling. Each muscle attaches to the bone on the pubis anteriorly and the ischiatic spine posteriorly. Between these two bone attachments, the muscle is linked through a tendineus arcade to the fascia of the muscle obturator internus. From this line of attachments, the muscle fibres are directed backwards, medially and downwards, to attach to the perineal body on the posterior wall of the anorectal junction and on the anococcygeal raphe. The muscle is subdivided into portions that are named according to their attachments and the pelvic viscera to which they are related: (1) pubococcygeus muscle (supe-

Fig. 1 Pelvic view of a male pelvic block (R rectum, U urethra)

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R. De Caro, A. Porzionato, V. Macchi

Fig. 2a-c Perineal (a) and pelvic (b) aspects of the levator ani muscle isolated from the sample of Figure 1. Histological macrosection of the levator ani (c) (azan-Mallory stain)

rior level), (2) iliococcygeus muscle (intermediate level) and (3) puborectal muscle (inferior level). The levator ani muscles with their attachments to the perineal body separate the anterior urogenital hiatus and the posterior anal hiatus. The ischio-

coccygeus muscle arises from the tip of the ischial spine and is attached to the lateral margins of the coccyx and the fifth sacral vertebra. The consistency of the levator ani and the course of its fibres are variable, and in particular, the ischiococ-

CHAPTER 1 • Perineum: Functional Anatomy

cygeus muscle may be nearly completely tendinous rather than muscular.

of fibromuscular tissue located between the rectum and urogenital triangles. It is attached to muscles and fasciae.

Urogenital Diaphragm The urogenital diaphragm is a muscular-fascial sheet triangular in shape (urogenital triangle), anteriorly and laterally bound deeply by the pubic symphysis and ischiopubic rami. In males, it is crossed by the urethra and in females by the urethra and the vagina. It includes two muscles that lie between the superior and deep fascia of the urogenital diaphragm. The deep transverse perinei is attached to the medial aspects of the ischiopubic rami; posteriorly, it is attached to the perineal body where its fibres decussate with those of the opposite side. Together with the superficial transverse perinei, the muscles may help support the visceral canals that pass through them. The compressor urethra is recognisable in females, and its fibres arise from the ischiopubic rami, pass anteriorly, and fuse with the contralateral fibres, lying anterior to the urethra below sphincter urethrae. However, the urethral sphincter mechanism is constituted by intrinsic striated and smooth muscle of the urethra and by fibres of the pubourethralis component of the levator ani, surrounding the membranous urethra in the male and the middle and lower thirds of the urethra in the female.

Superficial Plane of the Perineum The superficial plane of the perineum contains superficial muscles, some placed around the terminal portion of the genital system (bulbospongiosus, ischiocavernosus and the superficial transverse perinei muscles) and others placed around the anal canal (external anal sphincter). This plane is limited superficially by the superficial perineal fascia.

Rectum The rectum (Fig. 3) is part of the large bowel and is about 12-cm long. It can be subdivided into superior and inferior parts. It is continuous with the sigmoid colon at the level of the third sacral vertebra. It descends in two curves on the sagittal plane: the sacral flexure of the rectum, along the sacrococcygeal concavity; and the perineal flexure, where it crosses the pelvic diaphragm. The passage through the pelvic diaphragm corresponds to the anorectal junction, and the angle it forms with the upper anal canal is termed the anorectal angle, 2–3 cm in front of and slightly below the tip of the coccyx. On the frontal plane, the rectum deviates in three lateral curves: the upper and lower are convex to the right; the middle bulges to the left. The taeniae blend above the rectosigmoid junction forming two wide muscular bands on the anterior and posterior aspects of the rectal wall. The upper third of the rectum is covered by the peritoneum on its anterior and lateral aspects; the middle third of the rectum is covered by the peritoneum only on the anterior aspect. The peritoneum is reflected superiorly onto the urinary bladder in males, to form the rectovesical pouch, or onto the posterior vaginal wall in females, to form the rectouterine pouch (pouch of Douglas). The peritoneum is loosely attached by fatty connective tissue to the muscular tunica, allowing for considerable expansion of the upper half of the rectum. In the internal surface of the rectum, some permanent semilunar transverse or horizontal folds are recognisable, consisting of the mucosa, the submucosa and the muscularis. The most superior fold, at the beginning of the rectum, and the middle fold, immediately above the rectal ampulla, are quite constant.

Anal Canal Perineal Body The perineal body is a poorly defined aggregation

The anal canal, 4-cm long, begins at the anorectal junction and is directed downwards and backwards. It is located between the perineal body an-

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R. De Caro, A. Porzionato, V. Macchi

b

teriorly, the anococcygeal ligament posteriorly and the ischiorectal fossae laterally. Sphincteric muscles surround the rectum along its course, and at rest they cause an oval slit in the anteroposterior plane rather than a circular canal. Three portions can be subdivided as follows: 1. The first portion, 15-mm long, beginning at the anorectal junction and ending at the dentate line, presents mucosa with a stratified cubic epithelium. There are six to ten vertical folds, the anal columns, which contain a terminal radicle of the superior rectal vessels. The lower ends of the columns are joined by mucosal folds, the anal valves, between which lie small recesses referred to as anal sinuses.

Fig. 3a,b Aspect of the female pelvic viscera during anatomical dissection (a). The forceps grasp the uterus (U) and the rectum (R) showing the rectouterine pouch (D). After removal of the peritoneum laterally to the cervix (b), dissection shows the inferior hypogastric plexus (asterisks). F fallopian tube, O ovary, IE external iliac artery, Ur ureter

In the embryonic period, the dentate line is the site of the anal membrane, appearing at the junction between the entodermic portion of the anal canal, derived from the cloacae, and the ectodermic portion, derived from the proctodeum. 2. The second portion, 15-mm long, is the transition zone, or pecten. It is nonkeratinised, stratified, squamous epithelium that lacks sweat and sebaceous glands and hair follicles but contains numerous somatic nerve endings. It extends from the dentate line to the white line of Hilton, corresponding to the intersphincteric anal groove (boundary between the lower border of the internal sphincter and the sub-

CHAPTER 1 • Perineum: Functional Anatomy

a

b

Fig. 4a,b Transverse sections of the female pelvic viscera with azan-Mallory (a) and Weigert-van Gieson (b) stains showing topography and histological characteristics of puborectal sling (PR), rectovaginal septum (RVS) and internal anal sphincter (I). U urethra, V vagina, A anal canal

cutaneous portion of the external sphincter). 3. The third part, 10-mm long, is located inferiorly to the white line of Hilton and is continuous with the skin. The walls of the anal canal are surrounded by the sphincteric complex, the puborectal muscle and the internal and external anal sphincters. Puborectal Muscle The puborectal muscle is the caudal and most medial portion of the levator ani and is constituted by a superior and inferior lamina (Fig. 4). The inferior lamina progresses backwards from the insertion on the pubis to join the contralateral muscle behind the anorectal junction. In this way, it forms a sling, anchoring the junction to the pubis and determining perineal flexure. Posteriorly, the anococcygeal ligament anchors the junction to

the coccyx. The muscle’s lateral fibres show anteroposterior direction, and the medial fibres show a descending longitudinal course and juxtapose with the smooth longitudinal musculature of the anal wall, interposing between the internal and the external sphincters. The most superficial anterior fibres of the puborectal muscle insert in front of the rectum and contribute to formation of the levator muscle of the prostate gland in the male and the pubovaginal muscle in the female. Their margins delimit the urogenital hiatus. Internal Anal Sphincter The internal anal sphincter (Fig. 4) is constituted by a thickening of the circular layer of the smooth muscle of the anal canal. It is 5- to 8-mm thick and surrounds the superior three fourths of the anal canal and ends at the level of the linea alba.

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R. De Caro, A. Porzionato, V. Macchi

External Anal Sphincter The external anal sphincter is a striated muscle surrounding the anal canal for its entire length and is formed by three parts: subcutaneous, superficial and deep. The first (subcutaneous) and the third (deep) parts of the muscle are ring-like and do not insert on the coccygeus, whereas the second part is oval and inserts on the coccygeus. The subcutaneous part is a flat band 15-mm wide surrounding the inferior part of the anal canal beneath the inferior margin of the internal sphincter. Anteriorly, some bundles insert onto the tendineus centre and mix with bundles from the superficial transverse muscles, whereas posteriorly they insert on the anococcygeal ligament. The superficial part arises from the posterior surface of the most caudal coccygeal vertebra and from the anococcygeal raphe. The muscle bundles are directed anteriorly to form two bands surrounding the inferior half of the internal sphincter and insert into the tendineus centre. This is the only part of the muscle that is anchored to the bone. It is interposed between the subcutaneous and deep part. The deep part is ring-like and surrounds the superior part of the internal sphincter. Posteriorly, it inserts on the anococcygeal ligament; anteriorly, some bundles continue with the bundles of superficial transverse muscle. Cranial bundles are not separable from the puborectal muscle. Besides these muscles, at the level of the anal canal, there are two other muscular formations without strict sphincterial functions: the muscle wrinkler of the anal skin and the muscularis mucosae.

It is responsible of the intersphincteric anal groove.

Muscularis Mucosa The muscularis mucosa is constituted by longitudinal and circular bundles of smooth muscular fibres located between the mucosal and submucosal layers. Innervation of the anal sphincters derives from: 1. The orthosympathetic nerve fibres: these arise from the lateral column of myelomeres T-11, T-12, L-1 and L-2 and run through the inferior hypogastric plexus to inhibit the musculature of the rectal ampulla and excite the musculature of the internal sphincter. 2. The parasympathetic nerve fibres: these arise from the sacral myelomeres S-2, S-3 and run through the pelvic splanchnic nerves (erigentes nerves) to excite the musculature of the rectal ampulla and to inhibit the internal sphincter. 3. The pudendal nerve: this runs through the inferior rectal branch arising from myelomeres S-2, S-3 and the perineal branch of S-4 to excite the musculature of the external sphincter and the puborectal muscle.

Personal Contributions Subperitoneal Connective Tissue in the Female Pelvis

Corrugator Cutis Ani The corrugator cutis ani corresponds to the common longitudinal muscular layer, interposed between the internal and the external sphincters, arising from the anorectal junction. It juxtaposes the longitudinal bundles of the intrinsic muscle layer of the anal wall. Distally, this muscle lamina becomes fibroelastic and divides into about ten fibroelastic septa irradiating and crossing the subcutaneous part of the external sphincter to insert into the derm of the perianal skin. One of these septa passes between the inferior margin of the internal sphincter and the external sphincter and is called the intermuscular anal septum.

Traditionally, a system of ligamentous suspensory structures (the sacropubic laminae of Farabeuf and the cardinal ligaments of Mackenrodt) is described in the female pelvis. According to some authors, the so-called visceral pelvic fascia (endopelvic fascia) includes a fibrous connective system that forms two paired ligaments [1]. The first ligament constitutes the sacropubic laminae of Farabeuf, which have an anteroposterior course and may be subdivided into four segments: sacrorectal, rectouterine, uterovesical and pubovesical. The second suspensory mechanism is constituted by the cardinal ligaments of Mackenrodt, which run transverse from the pelvic wall to the uterine cervix. These structures should sus-

CHAPTER 1 • Perineum: Functional Anatomy

tain the pelvic organs, particularly the cervix, together with the connective condensations forming visceral fascias (rectal, cervicovaginal and vesical fascia, respectively). The spaces among them are filled with fibroadipose tissue that, according to anatomical literature, has no active role in supporting the intrapelvic organs. In De Caro et al. [2], the subperitoneal connective tissue was studied with histological and morphometric techniques and plastination. The subperitoneal connective tissue of the female pelvis consists of varying amounts of adipose tissue divided into small lobules by thin connective laminae. These laminae are connected to the visceral and parietal layers of the pelvic fascia and are closely connected to the vascular and nervous bundle sheaths crossing the pelvis. At the level of the so called sacrouterine and cardinal ligaments, we were unable to find connective ligamentous structures, and they correspond respectively to the inferior hypogastric plexus and uterine vessels, around which there is areolar adipose tissue with smooth muscle cells. In the absence of real connective ligaments, the subperitoneal connective tissue forms a three-dimensional network of thin connective laminae that are connected to the visceral adventitia, parietal layer of the pelvic fascia and neurovascular bundles crossing the pelvis. These connective laminae surround the adipose lobules of different sizes (smaller near the viscera; larger at the periphery). The subperitoneal connective tissue constitutes an anatomical structure that, beyond the functional limits of any individual ligament, may have “active” supporting properties. Rectourethralis Muscle The rectourethralis muscle has been described in different ways in the literature. Henle [3], in his first description of the “prerectal” muscle, did not define its attachments. In the work by Roux [4], muscle fibres were described as deriving, to a minor extent, from the dorsal aspect of the inferior half of the prostatic urethra and, to major extent, from the membranous urethra. Both bundles were described as travelling obliquely backwards and upwards to the anterior rectal wall and passing through the longitudinal and circular muscular layers, ending in the submucosa. For Poirier [5] the rectourethralis muscle represented a reinforcement of the rectal musculature in the male. In

his description, muscle fibres attached to the urogenital diaphragm, the urethral musculature and the prostate and went towards the anterior rectal wall. Some fibres travelled upwards, attaching to the inferior aspect of the peritoneum of the culde-sac of Douglas, whereas other more numerous fibres attached to the rectal wall, travelling upwards and downwards and continuing with the longitudinal and circular muscular layers. According to Wesson [6], the rectourethralis muscle attached posteriorly to the anterior longitudinal layer of the rectum, at the level of the verum montanum and coursed forwards to attach anteriorly to the posterior raphe of the external urethral sphincter. This muscle would be responsible for the perineal flexure of the rectum and its close approach to the prostate apex. Myers et al. [7] confirmed the presence of muscular bands attaching anteriorly into the perineal body and posteriorly to the anal canal (anoperineal bands) and to the anterior surface of the rectum (rectoperineal bands). Brooks et al. [8] described it as arising as two lateral arms from the smooth muscle of the anterior rectal wall, fusing in the midline and attaching to the perineal body. In addition, Matsubara et al. [9] found that at the interface between the rectourethralis muscle and the rectum, there was an intermingling of fibres with the outer layer of the longitudinal smooth muscle of the rectum. The analysis by our group [10] showed that the fibres of the rectourethralis muscle attached to the longitudinal muscular layer of the rectum and of the anal canal. In no histological sections were fibres seen extending to the circular layer or to the submucosa, as formerly stated by Roux and Poirier [4, 5]. We also confirmed the presence of the two components of the muscle, i.e., the rectoperinealis and the anoperinealis muscles. Concerning the anterior portion of the muscle, both sagittal and transverse sections showed clear separation of its smooth fibres from the prostatic and membranous urethra and their attachment to the perineal body. The rectourethralis muscle, being separated from the prostatic and membranous urethra by the septum rectovesicale, is located in the caudal portion of the prerectal space. This location and, in particular, the absence of attachment to the prostatic or membranous urethra make the original term “prerectal” as used by Henle more correct than the term “rectourethralis”. The latter term, in fact, was introduced by authors who considered the muscle to directly attach to the urethra.

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R. De Caro, A. Porzionato, V. Macchi

Rectovaginal Septum The rectovaginal septum (RVS) (Fig. 4) is commonly described as a strong connective tissue between the rectum and the vagina. Through an histological, plastination and morphometric study [11], the RVS has been evaluated on transverse sections collected at the cranial and caudal levels of the middle third (level II) and inferior third (level III) of the vagina. The RVS is located in an oblique coronal plane, close to the posterior vaginal wall, and is formed by a network of collagen, elastic fibres, smooth muscle cells with nerve fibres emerging from the autonomic inferior hypogastric plexus and variable numbers of small vessels. The RVS is thicker at cranial levels II and III with respect to caudal level II, both in the midline (1.75 and 1.70 vs. 0.2 mm, p