Research into Spinal Deformities (Studies in Health Technology and Informatics, 91)

RESEARCH INTO SPINAL DEFORMITIES 4

Studies in Health Technology and Informatics Editors Jens Pihlkjaer Christensen (EC, Luxembourg); Arie Hasman (The Netherlands): Larry Hunter (USA): Ilias Iakovidis (EC, Belgium); Zoi Kolitsi (Greece): Olivier Le Dour (EC, Belgium); Antonio Pedotti (Italy); Otto Rienhoff (Germany): Francis H. Roger France (Belgium); Niels Rossing (Denmark); Niilo Saranummi (Finland): Elliot R. Siegel (USA): Petra Wilson (EC, Belgium)

Volume 91 Earlier published in this series Vol. 63. R. Rogers and J. Reardon. Recommendations for International Action Vol. 64. M. Nerlich and R. Kretschmer (Eds.), The Impact of Telemedicine on Health Care Management Vol. 65. J. Manas and A. Gasman (Eds.), Textbook in Health Informatics Vol. 66. The ISHTAR Consortium (Eds.), Implementing Secure Healthcare Telematics Applications in Europe Vol. 67. J Oates and H. Bjerregaard Jensen (Eds.). Building Regional Health Care Networks in Europe Vol. 68. P. Kokol, B. Zupan. J. Stare, M. Premik and R. Engelbrecht (Eds.). Medical Informatics Europe '99 Vol. 69. F.-A. Allaert. B. Blobel. C.P. Louwerse and E.B. Barber (Eds.). Security Standards for Healthcare Information Systems Vol. 70. J.D. Westwood. H.M. Hoffman. G.T. Mogel. R.A. Robb and D Stredney (Eds.). Medicine Meets Virtual Reality 2000 Vol. 71. J.T. Ottesen and M. Danielsen (Eds.), Mathematical Modelling in Medicine Vol. 72. I. Iakovidis, S. Maglavera and A. Trakatellis (Eds.), User Acceptance of Health Telematics Applications Vol. 73. W. Sermeus, N. Kearney. J. Kinnunen, L. Goossens and M. Miller (Eds.). WISECARE Vol. 74. O. Rienhoff. C. Laske, P. van Eecke, P. Wenzlaff and U. Piccolo (Eds.), A Legal Framework for Security in European Health Care Telematics Vol. 75. G.O. Klein (Ed.). Case Studies of Security Problems and their Solutions Vol. 76. E.A. Balas. S.A. Boren and G D. Brown (Eds.). Information Technology Strategies from the United States and (he European Union Vol. 77. A. Gasman. B. Blobel. J. Dudeck. R. Engelbrecht. G. Gell and H. -U. Prokosch (Eds.). Medical Infobahn for Europe Vol. 78. T. Paiva and T. Penzel (Eds.), European Neurological Network Vol. 79. A. Marsh. L. Grandinetti and T. Kauranne (Eds.). Advanced Infrastructures for Future Healthcare Vol. 80. R.G. Bushko, Future of Health Technology Vol. 81. J.D. Westwood. H.M. Hoffman. G.T. Mogel, D. Stredney and R.A Robb (Eds.). Medicine Meets Virtual Reality 2001 Vol. 82. Z. Kolitsi (Ed.). Towards a European Framework for Education and Training in Medical Physics and Biomedical Engineering Vol. 83. B. Heller. M. Löffler, M. Musen and M. Stefanelli (Eds.), Computer-Based Support for Clinical Guidelines and Protocols Vol. 84 V L. Patel. R. Rogers and R. Haux (Eds.). MEDINFO 2001 Vol. 85. J.D. Westwood. H.M. Miller Hoffman. R.A. Robb and D. Stredney (Eds.). Medicine Meets Virtual Reality 02/10 Vol. 86. F. H. Roger-France, I. Mertens. M.-C. Closon and J. Hofdijk (Eds.). Case Mix: Global Views. Local Actions Vol. 87 F. Mennerat (Ed.). Electronic Health Records and Communication for Better Health Care Vol. 88 A. Tanguy and B. Peuchot (Eds.). Research into Spinal Deformities 3 Vol. 89 B. Blobel, Analysis. Design and Implementation for Secure and Interoperable Distributed Health Information Systems Vol. 90 Gy. Surján. R. Engelbrecht and P. McNair (Eds.). Health Data in the Information Society ISSN: 0926-9630

Research into Spinal Deformities 4 Edited by

Theodoros B. Grivas Orthopaedic Department, "Thriasio" General Hospital, Magula, Greece

IOS Press

Ohmsha

Amsterdam • Berlin • Oxford • Tokyo • Washington, DC

© 2002, The authors mentioned in the Table of Contents All rights reserved. No pan of this book may be reproduced, stored in a retrieval system, or transmitted. in any form or by any means, without prior written permission from the publisher. ISBN I 58603 289 5 (IOS Press) ISBN 4 274 90552 7 C3047 (Ohmsha) Library of Congress Control Number: 2002113598

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Preface On the 24-27 May 2002, the International Research Society of Spinal Deformities (IRSSD) held its fourth biannual scientific meeting at the Astir Palace Resort. Vouliagmenis, in Athens, by the beautiful and serene setting of the Aegean Sea. The extended essays of the papers and posters presented at the meeting are included in this book unmodified. Presentations where the authors failed to submit the extended texts have not been included. The scientific seeds planted at the previous meetings of the IRSSD gave this 4th Meeting a wide variety and a rich collection of 132 papers on research and related clinical practice, which were presented by delegates from 23 countries, from all the continents. Information about the history of the IRSSD. the previous forms of the society and its transformation, which led to the foundation of the IRSSD in Pescara in 1994 can be found in the previous books of "Research into Spinal Deformities, Volume 1-3". and will not be repeated here. The meeting comprised 17 Scientific Sessions on Spinal Deformities: Aetiology. Incidence. Natural History and Prognosis. Genetics and Growth. Anatomy, Pathology and Basic Science. Assessment, Biomechanics, Gait, Surface Topography, Imaging, Morphological Aspects (3-D) of Spinal Deformity. Technology, Cervical Spine, Spondylolisthesis - Low Back Pain. Conservative Treatment - (Physiotherapy - Brace), Surgical Treatment and Outcome. The programme was completed with three keynote lectures, the presidential address and three round table discussions. Particular emphasis was given to the scientific programme, in order to have a well-balanced amount of research and clinical papers on Spinal Deformities. The scope of this policy was not only to disseminate the latest trends of research in spinal deformities to the clinical environment, but also for researchers to have analogous input from the problems of recent clinical practice, so that the consequent interaction could be productive in a collegial, international atmosphere, with approximately 200 registered delegates. The objectives of the Society, to fuse together different trends of research in spine deformities, was thus fulfilled during the meeting, as Prof. Sevastik also highlighted in a previous meeting of the IRSSD. As chairman of the 2002 Athens meeting I wish to express sincere thanks to the members of the International Scientific Committee: Mark Asher (USA), Carl-Eric Aubin (Canada), Alexandros Chatzipavlos (Greece), Peter Dangerfield (England). Panagiotis Korovesis (Greece). Hubert Labelle (Canada), Morey Moreland (USA), George Sapkas (Greece). John Sevastik (Sweden), Panagiotis Soucacos (Greece). Ian Stokes (USA), Nobumasa Suzuki (Japan), Dirk Uyttendaele (Belgium), who during their busy schedule took the time to evaluate the number of abstracts that were submitted. To our great satisfaction this meeting exceeded our common expectations. This

was indeed very satisfying, as more colleagues are starting to take an interest in the research field of spinal deformities. I would like to thank the President of the IRSSD, Professor Nobumasa Suzuki, for raising the sum of $10,000, in order to contribute to the meeting. Also the sponsoring companies, Biomet Merck Hellas, Depuy Medec, Ebedent, Iamex, Mathys Medical, Medical Plus, Ortholand, Plus Endoprothetic Hellas, Unimed, who supported this meeting with their generous contributions. The Congress Organisers and Secretariat "Aktina - City Congress SA" for their faultless organization at the meeting, and last but not least, I would like to thank all the participants, without whom the Meeting would not have been possible. I hope that all participants found this meeting rewarding. Athens, May 2002 Dr. Theodoros B. GRIVAS, MD

Table 1. Statistical data relating to the delegates No. 1 2 3

4 5 6 7 8 9

10 12 13

14 15 16 17

18 19 20 21 22 23

Total

Country Australia Belgium Brazil Canada Switzerland Chile Czech Republic Germany France United Kingdom Greece Italy Israel Ireland Japan Malaysia The Netherlands Poland Russia Sweden Saudi Arabia Turkey United States Delegates Nurses Accompanying Persons Exhibitors

No. of Delegates

4 6 1 14 2 2 1 3 13 11

71 10 3 2 11 3 3 12 2

2 1 2 22

153 20 19 35

Contents Preface, T.B. Grivas The Effects of Exposure to Intense, 24 h Light on the Development of Scoliosis in Young Chickens, F. Nette, K. Dolynchuck, X. Wang, A. Daniel, C. Demianczuk, M. Moreau, J. Raso, J. Mahood and K. Bagnall Is the Labyrinthine Dysfunction a Causative Factor in Idiopathic Scoliosis? G. Kapetanos, M. Potoupnis, A. Dangilas, K. Markou and J. Pournaras Is the Central Nervous System a Causative Factor in Idiopathic Scoliosis? M. Potoupnis, G. Kapetanos, V.K. Kimiskidis and P.P. Symeonides The NOTOM Hypothesis for Idiopathic Scoliosis: Is it Nullified by the Delayed Puberty of Female Rhythmic Gymnasts and Ballet Dancers with Scoliosis? R. G. Burwell and P.M. Dangerfield Etiologic Theories of Idiopathic Scoliosis: Neurodevelopmental Concepts to be Evaluated, R. G. Burwell and P.H. Dangerfield Study of the Rib Cage Deformity in Children with 10°-20° of Cobb Angle Late Onset Idiopathic Scoliosis, using Rib-Vertebra Angles — Aetiologic Implications, T.B. Grivas, P. Samelis, T. Chadziargiropoulos and B.D. Polyzois Lateral Spinal Profile in School-screening Referrals with and without Late Onset Idiopathic Scoliosis 10°-20°, T.B. Grivas, S. Dangas, P. Samelis, C. Maziotou and K. Kandris Etiologic Theories of Idiopathic Scoliosis: The Apical Spinal Deformity — Relevance to Surgical Practice, R.G. Burwell, R.K. Pratt and J.K. Webb Etiology of the So-called "Idiopathic Scoliosis". Biomechanical Explanation of Spine Deformity. Two Groups of Development of Scoliosis. New Rehabilitation Treatment; Possibility of Prophylactics, T. Karski Comparison of Body Weight and Height Between Normal and Scoliotic Children, T.B. Grivas, A. Arvaniti, C. Maziotou, M. Manesioti and A. Fergadi Evolution of 3D Deformities in Adolescents with Progressive Idiopathic Scoliosis, I. Villemure, C.-É. Aubin, G. Grimard, J. Dansereau and H. Labelle Adolescent Idiopathic Scoliosis: Natural History and Prognosis, C.J. Goldberg, D.P. Moore, E.E. Fogarty and F.E. Dowling Prediction of Spinal Deformity in Scoliosis from Geometric Torsion, P. Poncet, J.L. Jaremko, J. Ronsky, J. Harder, J. Dansereau, H. Labelle and R.F. Zernicke The Natural History of Early Onset Scoliosis, C.J. Goldberg, D.P. Moore, E.E. Fogarty and F.E. Dowling The Incidence of Idiopathic Scoliosis in Greece — Analysis of Domestic School Screening Programs, T.B. Grivas, K. Koukos, U.I. Koukou, C. Maziotou and B.D. Polyzois School Screening in the Heavily Industrialized Area — Is There Any Role of Industrial Environmental Factors in Idiopathic Scoliosis Prevalence? T.B. Grivas, P. Samelis, B.D. Polyzois, B. Giourelis and D. Polyzois Biomechanical Factors Affecting Progression of Structural Scoliotic Curves of the Spine, S. Lupparelli, E. Pola, L. Pitta, O. Mazza, V. De Santis and L. Aulisa Positional Cloning Strategies for Idiopathic Scoliosis, S. Bashiardes, R. Veile, C.A. Wise, L. Szappanos and M. Lovett

1 1 10 12 15 20 25 32 37 47 54 59 64 68 71 76 81 86

Prediction of Curve Progression in Idiopathic Scoliosis from Gene Polymorphic Analysis, M. Inane, S. Minami. Y. Nakata, M. Takaso. Y. Otsuka, H. Kitahara, K. Isobe, T. Kotani, T. Marina and H. Moriya Mechanical Modulation of Vertebral and Tibial Growth: Diurnal versus Full-time Loading. I.A Stokes, J. Gwadera, A. Dimock and D.A. Aronsson Growth Patterns in Patients with Unoperated Congenital Vertebral Anomaly. C.J. Goldberg, D.P. Moore. E.E. Fogarty and F.E. Dowling Morphometric Characteristics of the Thoracic and Lumbar Pedicles in the Greek Population. A. Christodoulou, T. Apostolou and I. Terzidis Does Coralline Hydroxyapatite Conduct Fusion in Instrumented Posterior Spine Fusion? P. Korovessis, M. Repanti and G. Koureas The Effects of Mechanical Loading on the mRNA Expression of Growth Plate Cells. I. Villemure, M.A. Chung, C.S. Seek, M.H. Kimm, J.R. Matyas and N.A. Duncan Back Shape Assessment in Each of Three Positions in Preoperative Patients with Adolescent Idiopathic Scoliosis (AIS): Evaluation of a 10-Level Scoliometer Method Interpolated to 18-Levels. R.G. Bunvell, R.K. Aujla, A.A. Cole, A.S. Kirby. R.K. Pratt. J.K. Webb and A. Moulton The Validity of Clinical Examination in Adolescent Spinal Deformities. C. Grosso. S. Negrini, A. Boniolo and A.Æ. Negrini New Approach to Objective Diagnostics of Polyfunctional Disorders of the Neuromuscular Regulation in Children with Various Forms of Spine Deformities. G.P. Dmitrieva, M.Y. Karganov. N.N. Khlebnikova, O.I. Kovaleva, M.I. Kozhevnikova. S.B. Landa and L.A. Noskin Spinal Mobility and EMG Activity in Idiopathic Scoliosis through Dynamic Lateral Bending Tests, O.C. Ciolofan. C.-É. Aubin. P.A. Mathieu, M. Beauséjour. V. Feipel and H. Labelle Three Dimensional Analysis of Chest Wall Motion during Breathing in Healthy Individuals and Patients with Scoliosis using an Ultrasonography-based System. T. Kotani, S. Minami, K. Takahashi. K. Isobe, Y. Nakata, M. Takaso. M. Inoue, S. Nishikawa, T. Maruta, T. Tamaki and H. Moriya Relation Between the Pelvis and the Sagittal Profile in Adolescent Idiopathic Scoliosis: The Influence of Curve Type. M. Charlebois, J.-M. Mac-Thiong, M.-P. Huot. J.A. De Guise, W. Skalli and H. Labelle Study of Patient Positioning on a Dynamic Frame for Scoliosis Surgery. K. Duke. J. Dansereau, H. Labelle, A. Koller, J. Joncas and C.-É. Aubin Joint Segmental Kinematic Trunk Motion and C.O.P. Patterns for Multifactorial Posturographic Analysis. M. D'Amico and P. Roncoletta Transverse Plane Pelvic Rotation Measurement, B. Lucas, M. Asher. T. Mclff, D. Lark and D. Burton Baropodographic Measurements and Averaging in Locomotion and Postural Analysis. M. D'Amico and P. Roncoletta Movement Analysis of Scoliotic Subjects using Fastrak, A. Rahmatalla, N. Chokalingam, P. Dangerfiehl. E.-N. Ahmed, T Cochrane. J Dove and N.Maffulli Motion Segment Stiffness Measured without Physiological Levels of Axial Compressive Preload Underestimates the in vivo Values in All Six Degrees of Freedom, M.G. Gardner-Morse, I.A. Stokes, D. Churchill and G. Badger Kinematic Differences in Lower Limb Gait Analysis of Scoliotic Subjects, N. Chokalingam. A. Rahmatalla. P. Dangerfield. T. Cochrane, E-N. Ahmed and J. Dove Assessing Changes in Three Dimensional Scoliotic Deformities with Difference Maps. D.L. Hill. D.C. Berg. T. Church and V J Raso

90 97 101 104 109 1 14

119 123

126

130

135

140 144 149 153 156

162 167

1 73 178

Three-dimensional Shape Analysis of the Scoliotic Spine using MR Tomography and Rasterstereography, E. Hierholzer and L. Hackenberg The Effect of Posture on Quantec Measurements, A.M. Macdonald, C.J. Griffiths, F.J. McArdle and M.J. Gibson Local Energy as a Measure of Back Symmetry in Scoliosis, N.G. Durdle, T. Soonawalla, V.J. Raso and D.L. Hill Monitoring the Thoracic Sagittal Curvature in Kyphoseoliosis with Surface Topography: A Trend Analysis of 57 Patients, F.J. McArdle, C.J. Griffiths, A.M. Macdonald and M.J. Gibson Use of Functional Tests to Increase the Efficiency of Scoliosis Screening Diagnosis by COMOT Method, V.N. Sarnadsky, N.G. Fomichev and M.V. Mikhailovsky Cotrel-Dubousset Instrumentation (CDI) in the Treatment of Congenital Spinal Deformities. Computer Topography Evalution, M.V. Mikhailovsky, V.N. Sarnadsky and A.L. Khanaev Three-dimensional Correction with CD Instrumentation and Harrington Rod in the Treatment of Idiopathic Scoliosis, M.V. Mikhailovsky, V.V. Novikov and V.N. Sarnadsky Motion Analysis of the Trunk and Spine. Surface Measurement using Computer Optical Topography, V.N. Sarnadsky, S.Y. Vilberger and N.G. Fomichev Development of the Neurocentral Junction as seen on Magnetic Resonance Images, T. Rajwani, R. Bhargava, R. Lambert, M. Moreau, J. Mahood, V.J. Raso, H. Jiang, EM. Huang, X. Wang, A. Daniel and KM. Bagnall The Components of the Magnetic Resonance Image of the Neurocentral Junction, T. Rajwani, EM. Hilang, C. Secretan, R. Bhargava, R. Lambert, M. Moreau, J. Mahood, V.J. Raso and KM. Bagnall Accuracy of Rasterstereography versus Radiography in Idiopathic Scoliosis after Anterior Correction and Fusion, L. Hackenberg, E. Hierholzer and U. Liljenqvist Spine-Rib Rotation Differences at the Apex in Preoperative Patients with Adolescent Idiopathic Scoliosis (AIS): Evaluation of a Three-level Ultrasound Method, R.G. Burwell, R.K. Aujla, A.A. Cole, A.S. Kirby, R.K. Pratt, J.K. Webb and A. Moulton Sagittal and Transversal Plane Deformity in Thoracic Scoliosis, T. Kotwicki A New X-ray Calibration/Reconstruction System for 3D Clinical Assessment of Spinal Deformities, F. Cheriet, L. Remaki, C. Bellefleur, A. Koller, H. Labelle and J. Dansereau Preliminary Study of a New Real-time Ultrasound Method for Measuring Spinal and Rib Rotation in Preoperative Patients with Adolescent Idiopathic Scoliosis (AIS), R.G. Burwell, R.K. Aujla, A.A. Cole, A.S. Kirby, R.K. Pratt, J.K. Webb and A. Moulton Geometric and Postural Analysis of Mild Idiopathic Scoliotic Patients, N. Champain, R. Dupuis, V. Pomero, B. Mouilleseaux, J. Dubousset and W. Skalli Self-calibration of Biplanar Radiographs for a Retrospective Comparative Study of the 3D Correction of Adolescent Idiopathic Scoliosis, J. Novosad, F. Cheriet, S. Delorme, S. Poirier, M. Beauséjour and H. Labelle Semi-automation of the 3D Reconstruction of the Spine using Wavelets and Splines, S. Deschênes, B. Godbout, W. Skalli and J. De Guise 3D Biplanar Statistical Reconstruction of Scoliotic Vertebrae, S. Benameur, M. Mignotte, S. Parent, H. Labelle, W. Skalli and J.A. De Guise 3D Detailed Reconstruction of Vertebrae with Low Dose Digital Stereoradiography, A. Le Bras, S. Laporte, D. Mitton, J.A. De Guise and W. Skalli Pre and Post 3D Modeling of Scoliotic Patients Operated with in situ Contouring Technique, R. Dumas, D. Mitton, J.P. Steib, J.A. De Guise and W. Skalli

\ 84 190 194 199 204 211 216 222 229 235 241

246 251 257

262 267 272 276 281 286 291

3D Reconstruction and Analysis of the Whole Trunk Surface for Non-invasive Follow-up of Scoliotic Deformities, V. Pazos. F. Cheriet, H. Lahelle and J. Dansereau Assessment of the Validity of Observing Three-dimensional Images of the Spine using Polarising, Synchronised Techniques. S. Salvador, X. Wang, M. Moreau, J. Rasa, J. Mahood, R. Currah and K. Bagnall Growth, Development and Puberty Indicators on Spinal Growth. P.H. Dangerfield Scoliosis Study using Finite Element Models, C.-É. Aubin The Role of Muscles and Effects of Load on Growth. I. Stokes and M. Gardner-Morse Achondroplasia: 3D-CT Evaluation of the Cervical Spine, I. Tsitouridis, D. Melidis, M. Iosifidis, A. Morichovitou, F. Goutsaridou. S. Stratilati, G. Giataganas and Ch. Papastergiou Malformations of the Craniocervical Junction: 3D-CT Evaluation, I. Tsitouridis, F. Goutsaridou. A. Morichovitou, G. Giataganas. M. Iosifidis. D. Melidis and S. Stratilati An Experimental Model of Adult-onset Slip Progression in Isthmic Spondylolistesis. A. Patwardhan, A. Ghanayem, J. Simonds. S. Hodges. L. Voronov, O. Paxinos and R. Havey The Significance of Correlation of Radiographic Variables and MOS Short-form Health Survey for Clinical Decision in Symptomatic Low Back Pain Patients. P. Korovessis, A. Dimas and E. Lambiris Sciatic Scoliosis, its Natural History and the Ability of the Mckenzie Management to Influence it. G.P. Spanos Pathomechanic Basics of Conservative Treatment of Progressive Idiopathic Scoliosis according to Dobosiewicz Method based upon Radiologic Evaluation. K. Dobosiewicz. J. Durmala, K. Czernicki, H. Jendrzejek Conservative Management in Patients with Scoliosis — Does it Reduce the Incidence of Surgery? H.-R. Weiss, G. Weiss and H.J. Schaar Influence of Method of Asymmetric Trunk Mobilization on Shaping of a Physiological Thoracic Kyphosis in Children and Youth Suffering from Progressive Idiopathic Scoliosis. K. Dobosiewicz, J. Durmala, H. Jendrzejek and K. Czernicki Curvature Progression in Patients Treated with Scoliosis In-patient Rehabilitation — A Sex and Age Matched Controlled Study. H.-R. Weiss and G. Weiss Exercise Efficiency of Girls with Idiopathic Scoliosis Based on the Ventilatory Anaerobic Threshold. J. Durmala, K. Dobosiewicz. H. Jendrzejek and W. Pius Side Shift Exercise for Idiopathic Scoliosis after Skeletal Maturity. T. Mamyama, T. Kitagawal, K. Takeshita and K. Nakainura Reversal of the Signs and Symptoms of Moderately Severe Idiopathic Scoliosis in Response to Physical Methods. M.C. Hawes and W.J. Brooks Long-term Effects of Scoliosis. M. Asher and D. Burton Quantitative Measurement of Spinal Brace Use and Compliance in the Treatment of Adolescent Idiopathic Scoliosis. G.P. Nicholson. M.W Ferguson-Pell. K. Smith. M. Edgar and T. Morley Is the Boston Brace Mechanically Effective in AIS? V.J. Raso, E. Lou,D.L. Hill. J.K. Mahood and M.J Moreau A Wearable Networked Embedded System for the Treatment of Scoliosis. M. Bazzarelli, N. Durdle, E. Lou. J. Raso and D. Hill Curve Progression and Spinal Growth in Brace Treated Idiopathic Scoliosis. D.J. Wever, K.A. Tonseth and A.G. Veldhuizen Personalized Biomechanical Modeling of Boston Brace Treatment in Idiopathic Scoliosis. D. Périé, C.-É. Aubin. M. Lacroix, Y. Lafon, J Dansereau and H. Labelle Intelligent Brace System for the Treatment of Scoliosis. F. Lou. D. Benfield. J. Raso. D. Hill and N. Durdle

296

300 305 309 314

318

320

322

325 332

336 342

348 352 357 361 365 369

372 378 383 387 393 397

Spine-straight Device for the Treatment of Kyphosis, E. Lou, J. Raso, D. Hill, N. Durdle and M. Moreau Study of Vertebral Morphology in Scheuermann's Kyphosis before and after Treatment, E. Pola, S. Lupparelli, A.G. Aulisa, G. Mastantuoni, O. Mazza and V. De Santis Biomechanics of the Conservative Treatment in Idiopathic Scoliotic Curves in Surgical "Grey Area", L. Aulisa, S. Lupparelli, E. Pola, A.G. Aulisa, G. Mastantuoni and L. Pitta Cell Viability and the Physical Environment in the Scoliotic Intervertebral Disc, S.R.S. Bibby, A. Meir, J.C.T. Fairbank and J.P.G. Urban Brain-stem Dysfunction and Idiopathic Scoliosis, E.K. Dretakis Finite Element Simulation of Various Strategies for CD Correction, V. Lafage, J. Dubousset, F. Lavaste and W. Skalli Idiopathic Scoliosis. Segmental Fusion with Transpedicular Screws, A. Christodoulou, A. Ploumis, C. Zidrou, J. Terzidis and J. Pournaras Spinal Surgery Procedure Discretization, E. Verniest, D. Chopin, A.-P. Godillon-Maquinghen, P. Drazetic, C.-É. Aubin and F.-X. Lepoutre Surgical Treatment of Scoliosis in Myelomeningocele, P. Parisini, T. Greggi, M. Di Silvestre, F. Giardina and G. Bakaloudis Use of a Transpedicular Drill Guide for Pedicle Screw Insertion in the Thoracic Spine, J.-M. Mac-Thiong, H. Labelle, M. Rooze, V. Feipel and C.-É. Aubin Surgical Management of a Congenital Kyphotic Deformity in an Adolescent, A. Christodoulou, A. Ploumis, J. Terzidis, K. Tapsis and P. Hantzidis The Role of Rigid vs. Dynamic Instrumentation for Stabilization of the Degenerative Lumbosacral Spine, P. Korovessis, Z. Papazisis and E. Lambiris Spine Deformity Correlates Better than Trunk Deformity with Idiopathic Scoliosis Patients' Quality of Life Questionnaire Responses, M. Asher, S.M. Lai, D. Burton and B. Manna The Rib Hump after Surgery for Early Onset Spinal Deformity, C.J. Goldberg, D.P. Moore, E.E. Fogarty and F.E. Dowling Trunk Deformity Correction Stability Following Posterior Instrumentation and Arthrodesis for Idiopathic Scoliosis, M. Asher, S.M. Lai, D. Burton and B. Manna Anterior Universal Spine System (USS) for Adolescent Idiopathic Scoliosis (AIS): A Follow-up Study using Scoliometer, Real-time Ultrasound and Radiographs, R.G. Burwell, R.K. Aujla, A.A. Cole, A.S. Kirby, R.K. Pratt, J.K. Webb and A. Moulton Long-term Follow-up of Surgically Treated AIS Patients, D. Hill, V.J. Raso, K. Moreau, M. Moreau and J. Mahood Assessing the Impact of Pelvic Obliquity in Post-operative Neuromuscular Scoliosis, M. Moreau, J. Mahood, K. Moreau, D. Berg, D. Hill and J. Raso Is This as Good as it Gets? It May Be, M. Asher Modification of the Spinal Peak Growth Velocity as a Possible Treatment for Adult Scoliosis, A.G. King Outcomes of Scoliosis Fusion — Is Stiff and Straight Better? M.S. Moreland Author Index

401 405 412 419 422 428 433 438 442 448 454 457 462 465 469

473 477 481 486 489 492 499

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Th.B. Grivus (Ed.) Research into Spinal Deformities 4 IOS Press, 2002

The effects of exposure to intense, 24 h light on the development of scoliosis in young chickens Farrell Nette*, Kim Dolynchuk*, Xiaoping Wang*, Ariadne Daniel*, Christina Demianczuk*, Marc Moreau, James Raso, James Mahood and Keith Bagnall*. Division of Anatomy* and Department of Surgery University of Alberta, Edmonton, Alberta, Canada. T6G 2H7 Tel: 780-492-7094 Fax: 780-492-0462 Email: kbagnall@med ualberta. ca Abstract. The aetiology of adolescent Scoliosis remains unknown and hindering research is the absence of an appropriate animal model. It is now well-established that pinealectomy in young chickens results in the development of scoliosis that has many of the characteristics seen in patients with adolescent idiopathic scoliosis but the mechanism underlying this phenomenon remains elusive. The principle product of the pineal gland is meiatonin and so many studies have focused on studying the effects of reduced levels of this hormone. The results have been mixed and the role of meiatonin remains un~ear. As meiatonin production is inhibited by light, it was hypothesised that providing the chickens with an environment consisting of intense, continuous light would reduce serum meiatonin levels and avoid any of the potential artifacts involved with the pinealectomy surgery. Consequently, pinealectomised and normal chickens were exposed to very intense light for complete 24 h in each day. At the end of 22 days in this environment serum meiatonin levels had been reduced to very low levels in all chickens. Most importantly, 15% of the normal chickens had developed scoliosis and the number of pinealectomised chickens that developed scoliosis increased from 50% to 80%. The results showed that a method for reducing serum meiatonin without pinealectomy has been established and which can be used in further experiments. Furthermore, the results also showed that reduced levels of serum meiatonin has significant effects on the development of scoliosis. The indication is that there is a threshold level of serum meiatonin below which scoliosis may develop probably in conjunction with some other factor which has yet to be identified.

1. Introduction Despite extensive research over the last 100 years [1], the cause of adolescent idiopathic scoliosis (AIS) remains a mystery. In particular, a useful animal model for research purposes has still to be developed. In recent years, pinealectomy in young chickens has consistently produced scoliosis that has many characteristics similar to those

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seen in patients with AIS [2,3] and this model has considerable potential. Unfortunately, the mechanism underlying this phenomenon in young chickens has yet to be elucidated and its transference to a mammalian model has yet to be established. The main product of the pineal gland is melatonin [4] and consequently many studies have focused on the effects of reduced levels of this hormone as the main contributing factor to the development of the scoliosis. Disturbingly, the results from some of these studies are contradictory and the role played by melatonin remains confused. The surgery associated with pinealectomy is extensive especially for such young animals and it has yet to be established conclusively that the underlying cause for the development of the scoliosis is the actual removal of the pineal gland and not some subtle artifact of the surgery. Certainly, low levels of serum melatonin seem to be associated with the development of scoliosis in this model but the actual role of melatonin remains to be established. The hormone melatonin is produced only while the animal is in the dark and creates a circadian rhythm [5]. For this experiment, it was hypothesized that an environment of continuous, intense light would produce reduced levels of melatonin similar to those seen following pinealectomy. The results of such a situation would show whether or not the surgery itself was an integral part in the production of the phenomenon as well as providing information which would help to clarify the role of reduced levels of serum melatonin.

2. Materials and Methods First Experiment Twenty-six, newly-hatched Mountain Hubbard (broiler) chickens were obtained from Lillydale hatchery in Udmonton. Ten of the chickens were randomly selected and placed in a 12-hour light-dark cycle (12D12L) to act as normal controls. The other 16 chickens were subjected to continuous, bright light (24L) with no dark component and acted as the experimental group. The chickens remained in their two groups in these environments for the entire experiment. A review of the literature indicated that a brightness of at least 700 lux would be required to reduce serum melatonin levels to zero [6]. Therefore, it was decided that a brightness of at least 1000 lux would be used for both the controls during the light cycle and continuously with the experimentals. This level of brightness was achieved through the use of two sets of floodlights in each room and a photometer was used to monitor the brightness each day. The two groups were housed in different rooms because of the different lighting conditions but the environmental conditions in the two rooms were kept identical. Both the experimental and control groups were given food and water ad libitum. Throughout the entire study, the chickens were observed closely several times a day, particularly for the development of any health problems.

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Collection of Blood Samples and Radioimmunoasssay Methodology Collection of blood samples for the analysis of serum melatonin levels occurred on day 15. At the time corresponding to the middle of the light cycle, 8 of the experimental and 5 control chickens were randomly chosen. The anterior chest wall was opened so that 1 ml of blood could be collected easily from each chicken directly from the left ventricle. This procedure was repeated with a similar number of chickens at the time corresponding to the middle of the dark phase on the same day. Collection in the dark required using a red light in the 1 2D 1 2L group to ensure that melatonin secretion was not affected. Unfortunately, 1 ml of blood is required for melatonin analysis and chickens of this age cannot survive the removal of this amount of blood, necessitating euthanasia. The analysis is described in further detail in previous publications [7]. Second Experiment One hundred and sixty, newly-hatched Mountain Hubbard chickens were obtained. They were randomly separated into 4 groups of 40 chickens each. Two of the four groups were chosen randomly and subjected to pinealectomy surgery. The chickens in the other two groups did not undergo surgery and acted as normal controls. One pinealectomised and one normal group were placed in a single, controlled environment on a 12-hour, light-dark cycle (1 2L 1 2D) at >1000 lux for the entire experiment. These two groups were identified as the "control pinealectomised" and the "control normals" respectively. The other two groups of chickens formed the experimental groups and were subjected to 24-hours of intense, bright light (24L) also at >1000 lux. These two groups were identified as the "experimental pinealectomised" and the "experimental normals" respectively. Collection of Blood Samples and Radjoimmunoassay Methodology Collection of blood samples for analysis of serum melatonin using radioimmunoassay techniques occurred twice during the experiment: on days 15 and 22. At the time corresponding to the middle of the light phase on day 15,10 chickens from the experimental pinealectomised group, 10 chickens from the experimental normal group, 10 chickens from the control pine alectomised group and 10 chickens from the control normal group were randomly chosen. This procedure was repeated in the middle of the dark cycle. Again, this required using a red light in the 12L12D group when collecting the samples to ensure that hormone levels were not affected. On day 22 at the time corresponding to the middle of the light cycle, 10 experimental pinealectomised, 10 experimental normals, 10 control pinealectomised and 10 control normals were randomly chosen. Each chicken was weighed and marked using a permanent marker. One ml of blood was collected from a wing vein of each chicken. The chickens were replaced into their respective rooms after the collection of blood was completed. The procedure was repeated at the time corresponding to the middle of the dark cycle with the remaining experimental and control chickens. Separate chickens were used for the collection of blood in the dark cycle to avoid any changes to serum melatonin levels if blood collection had occurred earlier in the day as well.

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3. Results First Experiment The results of the serum assays in the first experiment are shown in Figure 1.

Figure 1. Average serum melatonin values from the first experiment in which blood samples were collected afier IS days. Control chickens (Control) were exposed to a 12:1 2h Iight:dark cycle whereas the experimental (Expt) group was exposed to 24h light. Blood was collected at a time corresponding to the middle of the dark phase (Midnight) and the middle of the light phase (Noon). Note the circadian rhythm in the control group of chickens and the lack of a rhythm in the experimental group.

Second Experiment The results from this experiment are shown in Figure 2.

Figure 2. Average serum melatonin values from the second experiment in which blood samples were collected after IS days. The control chickens (Control) were exposed to a 12: 12h light:dark cycle whereas the experimental (Expt) group was exposed to 24h light. Blood was collected at a time corresponding to the middle of the dark phase (PM) and the middle of the light phase (AM). Note that the average serum melatonin level in the control, normal group of chickens in the middle of die dark cycle was significantly larger than any of the other values. Note too that the average values in all groups where die chickens had been pinealectomised showed low levels of serum melatonin. ilowever, while die normal chickens in die experimental conditions (24h light) did not show a circadian rhythm, these average results were significantly larger than those found in all groups of pinealectomised chickens.

The data for the blood samples collected during the middle of the light phase after 22 days are shown in Figure 3. Figure 4 shows the results collected at the time corresponding to the middle of the dark phase after 22 days. Measurement of the Cobb angles from the radiographs indicated that none of the normal chickens kept in the 12L12D cycle developed scoliosis. In contrast, 50% (10/20) of the pinealectomised

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chickens kept in the same conditions did develop scoliosis. Most interestingly, the results also showed that 15% (3/20) of the non-pine alectomi sed chickens in the experimental group (24h continuous, intense light) developed scoliosis whereas 80% (16/20) of the pinealectomised chickens kept in the same conditions (24L) also developed scoliosis. The average degree of scoliosis that developed was not significantly different between any of the groups where some chickens developed scoliosis.

Figure 3. Average serum nielatonin values from the second experiment in which blood samples were collected at the time equivalent to the middle of the light phase after 22 days. The control chickens (C) were exposed to a 12:12h light:dark cycle whereas the experimental (E) group was exposed to 24h light. The chickens in some of the groups underwent pinealectomy (PINX) and some did not (NOR) and acted as controls. The chickens in each group were also divided into those that developed scoliosis (Scol) and those that did not (None). Note that all values of average serum melatonin levels are close to zero but that the values for the experimental normal chickens (24L, non pinealectomised) are significantly greater than some of the other values.

Figure 4. Average serum melatonin values from the second experiment in which blood samples were collected at the time equivalent to the middle of the dark phase after 22 days. The control chickens (C) were exposed to a 12:12h light:dark cycle whereas the experimental (E) group was exposed to 24h light. The chickens in some of the groups underwent pinealectomy (PINX) and some did not (NOR) and acted as controls. The chickens in each group were also divided into those that developed scoliosis (Scol) and those that did not -one). Note that the value for average serum melatonin in the control group of normal chickens (12L12D, not pinealectomised) is significantly larger than all other values which are low.

4. Discussion The results of this study have clearly shown that it is possible to manipulate the serum levels of melatonin in young chickens by using intense, consistent light of >1000



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lux. Consequently, a method is available by which serum melatonin levels can be reduced to at least close to zero without the extensive surgery associated with pinealectomy. Perhaps the most significant result from this study is that 15% of the normal chickens that were exposed to intense, continuous light developed scoliosis. In addition, while it was expected from the results of previous experiments that approximately 55% of the pinealectomised chickens would develop scoliosis (actually 50% in this experiment), the results showed that this figure was increased to 80% when the chickens were exposed to the intense light after being pinealectomsied. These are exciting results because they suggest that reduced levels of melatonin are certainly involved in the development of the scoliosis and are not just correlated to the phenomenon. These results suggest that that there is possibly a threshold level of serum melatonin below which scoliosis can develop.

5. Acknowledgements The authors would like to thank the Edmonton Orthopaedic Research Association and the Scoliosis Research Society for providing funding for this work.

References 1. 2.

3.

4. 5. 6. 7.

R.C. Robin, The Aetiology of Idiopathic Scoliosis. CRC Press, Boca Raton, 1990. Wang X, Jiang II, Raso VJ, Moreau M, Mahood J, Zhao J, Bagnall KM. Characterization of the scoliosis that develops following pinealectomy in the chicken and comparison with the scoliosis seen in adolescent idiopathic scoliosis in humans. Spine 1997; 22:17-25. Wang X, Moreau M, Raso JV, Zhao J, Hongxing J, Mahood J, Bagnall KM. Changes in serum melatonin levels in response to pinealectomy in the chicken and its correlation with development of scoliosis. Spine 1998; 23:2377-2382. Pelham RW. A serum melatonin rhythm in chickens and its abolition by pinealectomy. Endocrinology, 7975, 96-2: 543-46. Binkley S. The pine-: endocrine and neuroendocrine function. Englewood Cliffs, NJ: Prentice Hall, 1988:246-61. Classen I1L, Riddell C, Robinson FE. Effects of increasing photoperiod length on performance and health of broiler chickens. British Poultry Science 1991; 32:21-29. Bagnall KM, Raso vJ, Hi- D, et al. Diurnal and nocturnal serum melatonin levels in girls with adolescent idiopathic scoliosis. Spine

77i.fi. Grivas(Ed.) Research into Spinal Deformities 4 IOS Press, 2002

Is the labyrinthine dysfunction a causative factor in idiopathic scoliosis? G.Kapetanos*, M. Potoupnis, Ang. Dangilas, K. Markou, J. Pournaras A' Orthopaedic Department - Aristotelian University of Thessaloniki - Greece ENT Department, "G. Papanikolaou " Hospital - Thessaloniki

*8 Martiou Str. Panorama - Thessaloniki - Greece — Post code:55236 Tel:+ 30310344271 - Fax:+ 303103442 71 Abstract. The cause of idiopathic scoiiosis remains unknown, although research has possibly eliminated some hypothetical causes. Recent reports associating scoliosis convexity with equilibrium control central processing and motor lateralization have suggested that idiopathic scoliosis is connected causally with the motor cortex. In order to analyze these factors a study of labyrinthine function was carried out. This study included seventeen female patients 12 to 14 years old (mean age= 13.36y) with right thoracic idiopathic scoliosis and twelve normal control females 12 to 14 years old (mean age =13.1y).An electro-nystagmographic study of labyrinthine function (potential nystagmus) was performed in all the patients of the study with caloric tests. The nystagmus was recorded with the electronystagmographic technique (ENG) using Hartmann device. We evaluate these parameters: Slow phase velocity (SPY), Total amplitude (Tamp), Frequency of nystagmus (Freq). No children of the study presented spontaneous nystagmus. No correlation was found between the convexity of the curvature and the direction of nystagmus in posture tests. There were no significant differences between left- and right- beating nystagmus. The results are discussed with special reference to aetiology in idiopathic scoliosis.

Idiopathic scoliosis is a three-dimensional deformity of the spine with lateral curvature combined with vertebral rotation. Although the clinical manifestations of this disease have been well described, no one has been able to determine the cause and pathogenesis [1,2]. The cause of idiopathic scoliosis remains unknown, although research has possibly eliminated some hypothetical causes [4,10]. The fact that many patients with idiopathic scoliosis appear to be out of balance has led many researchers to postulate that a brain stem abnormality involving the vestibular system is the cause of this condition [6,8,9]. The aim of this study was to evaluate the postural effects on nystagmus response during caloric vestibular stimulation. The study included seventeen female patients 12 to 14 years old (mean age=13.36y) with right thoracic idiopathic scoliosis (study group). All patients had a single major structural curvature between 20°-40° [3]. The control group comprised twelve non-scoliotic healthy subjects in the same age group (mean age=13.1y) and with about the same sex ratio. In all patients of the study an electronystagmographic study of labyrinthine function with caloric stimulation was performed. The recordings were performed in a

G. Kapctanos et al. / I s the Lahyrinthine l~)\sfunction a Causative h actor'

dark, silent room with the test subject supine and with eyes closed. Electrodes were placed at each outer canthus for recording horizontal nystagmus (?]. The caloric tests were performed according to the method of Fitzgerald and Hallpike with slight modifications [5]. The syringings were performed with carefully controlled temperatures 30°C and 44°C in each ear. The following four test situations were studied in the supine position with the subject's head in 30° flexion. Warm water 44°C in the right ear, warm water in the left ear, cold water 30°C in the left ear and cold water in the right ear. The syringing was performed for 45 seconds with a water volume 250cc. The time between two syringings was lOminutes. The recording time in each position was at least 60 seconds. The direction of nystagmus and intensity were registered. We evaluated these parameters for each patient: The frequency of nystagmic movements, the amplitude of nystagmic movements and the slow phase velocity of nystagmus. Therefore we determined the difference in sensitivity between the labyrinths and between left- and right- beating nystagmus in relation to the total response. These differences in labyrinthine sensitivity, evaluated with the use of unilateral weakness parameter. The differences in left- and right- beating nystagmus evaluated with the use of directional preponderance parameter. No one children of the study present spontaneous nystagmus or positional nystagmus. No significant correlation was noted between direction of convexity and nystagmus. Five patients from the study group (29.4%) revealed preponderance of the right-beating nystagmus. Four patients of the study group (23.5%), revealed unilateral weakness (difference between left and right labyrinth>20%) with dominance of the right labyrinth. Twelve patients from the study group (70.5%) did not reveal unilateral weakness (difference between left and right labyrinth 0.05, t-test). The side-to-side difference of UT,MT and LT were 4.5±2.4,4.3±2.8 and 4.4±3.7. None of all the above parameters differed significantly from those of the control group (p>0.05, t-test). The study is continuing with increase of the number of subjects. The present study did not reveal asymmetries or pathological alterations in the corticomotor excitability of patients with idiopathic scoliosis. Although more research is needed to confirm and determine this problem. References 1. 2. 3. 4. 5. 6. 7. 8. 9.

Barrack R.L., Whitecloud T.S., Burke S.W., Cook S.D., Harding A.F.: Proprioception in idiopathic scoliosis.Spine 9:681-685,1984 Brinker M.R., Willis J.K., Cook S.D., Whitecloud T.S., Bennett J.T., Barrack R.L., Ellman M.G.: Neurologic testing with somatosensory evoked potentials in idiopathic scoliosis. Spine 17:277279,1992 Burwell R.G., Cole A.A., Cook T.A., et al: Pathogenesis of idiopathic scoliosis. The Nottingham Concept. Acta Orthop. Belg. 58(suppl.l):33-58,1992 Cobb JR: Outline for the study of scolosis. In Instructional Course Lectures, The American Academy of Orthopaedic Surgeons. Vol.5,pp.261-275. Ann Arbor, J.W.Edwards, 1948 Herman R., Mixon J., Fisher A., Maulucci R., Stuyck J.: Idiopathic scoliosis and the central nervous system: A motor control problem. Spine 10:1-14,1985 Machida M.: Cause of idiopathic scoliosis. Spine Vol.24-24:2576-2583,1999 Miller N.H.: Cause and natural history of adolescent idiopathic scoliosis. Orthopaedic Clinics of North America, 30(3):343-352, 1999 Mills K.R., Nithi K.A.: Corticomotor threshold to magnetic stimulation: Normal values and repeatability. Muscle and Nerve:570-575, May 1997 Woods L.A., Haller R.J., Hansen P.D., et al: Decreased incidence of scoliosis in hearing-impaired children: Implications for a neurologic basis for idiopathic scoliosis. Spine 20:776, 1995

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The NOTOM Hypothesis for Idiopathic Scoliosis: Is it Nullified by the Delayed Puberty of Female Rhythmic Gymnasts and Ballet Dancers with Scoliosis? R G Burwell1 & P H Dangerfield2 'The Centre for Spinal Studies and Surgery, Nottingham and2 Department of Human Anatomy and Cell Biology, University of Liverpool and Royal Liverpool Children's Hospital, Alder Hey, Liverpool, UK Abstract. Nachemson [3] suggested that there are more girls than boys with progressive adolescent idiopathic because of a different timing between skeletal maturation and postural maturation in the sexes during adolescence. We termed Nachemson's concept the neuro-osseous timing of maturation (NOTOM) hypothesis and used it to propose a possible medical treatment for idiopathic scoliosis by delaying puberty through the pituitary using gonadorelin analogues as in idiopathic precocious puberty [1,2]. The prevalence of scoliosis is reported to be increased in rhythmic gymnasts (RGs) in Bulgaria [4] and in ballet dancers (BDs) in the USA [S]. Both groups exhibit delayed puberty, which, at first sight, nullifies the NOTOM hypothesis for idiopathic scoliosis. While constitutional and environmental factors may determine these scolioses, the different curve types in RGs and BDs suggest that the exercise pattern over many years determines which type of scoliosis develops, although not the curve severity. We support the view that scoliotic RGs should be included in a group of sportsassociated scoliosis separate from idiopathic scoliosis [4]. Hence the delayed puberty of RGs and BDs with scoliosis does not nullify the NOTOM hypothesis as their scolioses are not idiopathic. There is a need to focus research on such subjects who have defined constitutional and environmental factors related to their scolioses.

1. Nachemson's concept and the NOTOM hypothesis Nachemson [3] suggested that there are more girls than boys with progressive AIS for the following reason. The maturation of postural mechanisms in the nervous system is complete about the same time in boys and girls. Girls enter their skeletal adolescent growth spurt with immature postural mechanisms. So, if they have a predisposition to develop a scoliosis curve, the spine deforms. In contrast, boys enter their adolescent growth spurt with mature postural mechanisms so they are protected from developing a scoliosis curve. We termed Nachemson's concept the neuro-osseous timing of maturation (NOTOM) hypothesis and used it to propose a possible medical treatment for idiopathic scoliosis by

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delaying puberty through the pituitary using gonadorelin analogues as in idiopathic precocious puberty [1,2].

2. The delayed puberty of rhythmic gymnasts and ballet dancers The prevalence of scoliosis is reported to be increased in rhythmic gymnasts (RGs) in Bulgaria [4] and in ballet dancers (BDs) in the USA [5]. Both groups exhibit delayed puberty, which, at first sight, nullifies the NOTOM hypothesis for idiopathic scoliosis.

3. Comparison of certain dietary, exercise, physical, biological and scoliosis features of rhythmic gymnasts and ballet dancers There are similarities between scoliotic RGs and BDs that include intensive exercise from a young age, dieting, delayed menarche, increased scoliosis prevalence (RGs 12%, BDs 24%), mild scoliosis curves (10-30 degrees), and presumably generalized joint laxity. Other differences in addition to country of origin and exercises, include certain anthropometric features and importantly in RGs, thoracolumbar and lumbar curves and, in BDs, right thoracic curves. 4. Interpretation of the differences between rhythmic gymnasts and ballet dancers We suggest that most BDs who develop mild-moderate scoliosis do not have idiopathic scoliosis but a scoliosis related to intensive exercises over many years acting on a particular phenotype and genotype, similar to the sports-associated scoliosis. We support the view that scoliotic RGs should be included in a group of sports-associated scoliosis separate from idiopathic scoliosis [4]. While constitutional and environmental factors may determine the scoliosis, the different curve types in RGs and BDs suggest that the exercise pattern over many years determines which type of scoliosis develops, although not the curve severity. 5. Conclusions 1. The delayed puberty of RGs and BDs with scoliosis does not nullify the NOTOM hypothesis as their scolioses are not idiopathic. 2. There is a need to focus research on rhythmic gymnasts and ballet dancers who have defined constitutional and environmental factors related to their scolioses.

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References 1. 2.

3.

4. 5.

R.G. Burwell, Biology is the future of scoliosis treatment. In, Research into Spinal Deformities 3. A. Tanguy, B. Peuchot (eds.), Amsterdam:IOS Press, 2002. R.G. Burwell, P.M. Dangerfield, A possible neuroendocrine method for delaying the adolescent growth spurt and slowing scoiiosis curve progression based on the NOTOM hypothesis: potential of a medical treatment for progressive juvenile and adolescent idiopathic scoliosis (JIS & AIS). Journal of Bone and Joint Surgery (Br) Orthopaedic Proceedings. In Press. A. Nachemson. In the discussion after the paper 'Aetiopathogenesis of idiopathic scoliosis' by R G Burwell. Second Annual Meeting, Societ£ Internationale de Recherche et d'Etude sur le Rachis, Barcelona, 28-30 November 1996. P.I. Tanchev et al., Scoliosis in rhythmic gymnasts. Spine 25(11): 1367-1372, 2000. M.P. Warren et al., Scoiiosis and fractures in young ballet dancers: relation to delayed puberty and secondary amenorrhea. New England Journal of Medicine 314(21):1348-1353, 1986.

Th.B. Grivas (Ed.) Research into Spinal Deformities 4 IOS Press, 2002

Etiologic Theories of Idiopathic Scoliosis: Neurodevelopmental Concepts to be Evaluated R G Burwell1 & P H Dangerfield2 'The Centre for Spinal Studies and Surgery, Nottingham and 2Department of Human Anatomy and Cell Biology, University of Liverpool and Royal Liverpool Children's Hospital, Alder Hey, Liverpool, UK Abstract. There is increasing interest in the concept that neuromuscular mechanisms and the central nervous system (CNS) are somehow involved in the etiology and pathogenesis of idiopathic scoliosis (IS). Yet in the extensive neuroscience research of idiopathic scoliosis certain neurodevelopmental concepts have been neglected. These include: (1) a CNS body schema for posture and movement control generated during development and growth by establishing a long-lasting memory; (2) pruning of cortical synapses at puberty; and (3) neuromorphic engineering. Memory of developing posture and movement might be established in neurons of the CNS body schema in the form of novel proteins; these could be coded by modified genes obtained by the recombination (crossing over) of DNA in a similar way to that in the production of immunological antibodies and during meiosis [11,27]. These concepts need evaluation in relation to (1) the etiopathogenesis of IS and (2) a possible new treatment approach to idiopathic scoliosis involving a neuromorphic device to control the output for muscle stimulators that are inserted and driven with telemetry.

l. Introduction There is increasing interest in the concept that neuromuscular mechanisms and the central nervous system (CNS) are somehow involved in the etiology and pathogenesis of adolescent idiopathic scoliosis [2-4,6,12,13,24,34-36]. Bagnall [3] outlines how neurological dysfunction associated with the feedback mechanism between ligaments and muscles might be involved in some cases of adolescent idiopathic scoliosis. Goldberg [16] takes a cautionary position and asks that supporters produce convincing evidence of a '...conclusive of a significant and meaningful abnormality in an overwhelming proportion of patients and absence in controls.' In the extensive neuroscience research of AIS certain neurodevelopmental concepts have been neglected. 2. A CNS internal body image or body schema generated during growth Postural control involves the capacity to build up internal representations for organizing sensory inputs and co-ordinating them with motor actions. The central nervous system matures with an internal body image, or CNS body schema, of posture

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and movement derived from proprioceptive, vestibular and visual input, to which heredity and learning contribute [17,18,26,32,33]. In this connection Shumway-Cook and Woollacott [32] note that in development, new behaviours and skills emerge from an interaction of the child and its maturing nervous and musculoskeletal system with the environment. An important part of interpreting senses and co-ordinating actions for postural control is the presence of an internal representation, or CNS body schema, providing a postural frame of reference. It has been hypothesised that this postural frame of reference acts as a comparator for incoming sensory inputs as an essential part of interpreting self-motion, and to calibrate motor actions. The CNS body schema concept implies that during development the effects of musculokeletal growth on body size and shape may involve the sensory inputs adjusting the CNS body schema so that it is unique for each individual ensuring that the motor control is established appropriately for that individual. This would involve storage in a long-lasting memory system, or systems, such as: • structural modifications of synaptic connections (neuronal plasticity at synapses due to the activation of protein kinases), resulting in alterations in the patterns of neural activity [15, 29,30], or • possibly other systems including proteins or memory coding by modified genes in brain DNA [11,15,27]. Changes in gene expression are considered essential for structural synaptic modifications [27]. Memory might be established in neurons of the CNS body schema in the form of novel proteins coded by modified genes obtained by the recombination (crossing over) of DNA in a similar way to that (1) in the production of immunological antibodies and (2) during meiosis [11,27]. According to this concept the DNA changes in response to new sensory experiences during development and growth and is stored. We suggest that idiopathic scoliosis might result from an abnormality in establishing this internal body image, or body schema within the central nervous system during development and growth. The defect may be in the DNA of neurons in the CNS body schema and specifically how the DNA sequences change in response to sensory inputs during development and growth. This concept links postnatal growth, posture, movement, somatotopic localisation in the CNS, memory and genetics. Perturbations of the CNS body schema evidently occur in some neurological disorders such as phantom limb and a wide variety of psychiatric disorders including schizophrenia (dysmorphic concern) [5]. 3. Pruning of cortical synapses at puberty Around the time of puberty in humans much of the synaptic architecture is broken down and remodeled; the onset of puberty coincides with the final regressive event in the CNS - elimination of 40% of neuronal synapses [19, 20-23]. In general, synapse elimination is thought to reflect a process where early in development synaptic contacts are made randomly. Then, in the subsequent course of development, only those connections that are stabilised are incorporated into functioning units or circuits, whereas those not incorporated become inactive and are eventually resorbed [23]. Competition for

R.G. Burwell and P.M. Dangerfield / Etiologic Theories ofldiopathic Scoliosis

17

a trophic factor, nerve growth factor (NGF), has been suggested as the underlying physiological mechanism [29,30]. Such pruning of synapses is thought to increase the efficiency of cognitive function that only emerges in adolescence [23]. Neuropathologic, EEG and brain metabolic studies provide evidence for peaks of cortical synaptic density around 4-10 years of age followed by decline during adolescence [7,8,23,28]. The pruning of cortical synapses at puberty might affect the development of the CNS body schema and alter the development of the symmetry of motor control of the trunk. This could contribute to the development of idiopathic scoliosis. According to Saugstad [31] early puberty results in an earlier end to synaptic pruning, increased synaptic connectivity in the cerebral cortex and increased risk of manicdepressive psychoses. In late maturers prolonged synapse elimination should lead to a lower cortical synaptic density, reduced synaptic connectivity and a diathesis for schizophrenia [25]. Are these psychoses related epidemiologically to adolescent idiopathic scoliosis? In schizophrenia there is an excess of ill-defined conditions in which scoliosis is not mentioned [10]. 4.Neuromorphic engineering Neuromorphic engineers look at brain structures and function and devise chips that contain neurons, axons and a primitive rendition of brain chemistry [1]. At the Telluride Workshop of 2001 [1] research was presented that involved the collaboration of a biologist (Avis Cohen who studies generation of swimming in lampreys), a robotics engineer and an analogue chip designer to create a tethered biped that uses the principle of the central pattern generator (cpg). In the biped, there is a small pair of legs, driven at hips with the knees allowed to move freely, swinging forward and backward under their own momentum. To make the robot walk, the hips are driven forwards and backwards by bursts of electrical energy triggered by the cpg. The robot has sensors that let it feel and respond to the hip angle. Because outputs from these sensors are fed directly back to the cpg, the robot literally learns to walk. The cpg works by charging and discharging an electrical capacitor. The clinical application of this model is a neuroprosthetic device for spinal cord injury patients. In discussing this work with Professor Avis Cohen [9] we asked if the concepts involved in their neuromorphic model might be applied to idiopathic scoliosis in (1) patients, and (2) finite element models. The aim would be to control the muscle contractions and make them more symmetric. Professor Cohen [9] advised that the neuromorphic device could be used to control the output for muscle stimulators that are inserted and driven with telemetry. The device is able to 'learn' to change its output with sensory feedback, say of asymmetry. This would allow the pattern of stimulation to change as the patient begins to change her output pattern. Dr Cohen writes, "Once it's known what the muscle activation patterns are, and their pattern of abnormality, it shouldn't be too difficult to take the device to the next stage. Presently there are stimulators (developed by Gerry Loeb at the University of Southern California) that can be implanted in muscles which the device could control."

R. G. Runvell and P H Dangerfield / Etiolngic Theories of Idiopathic Scoliosis

The limitation at present to the possible application of this neuromorphic model to the treatment of idiopathic scoliosis is lack of knowledge about the muscles that might trigger/exacerbate the spinal deformity. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

17. 18. 19. 20. 21. 22. 23. 24. 25. 26.

Anonymous, Machines with a human touch. The Economist Technology Quarterly, September 22nd pp 28-30, 2001. K.M.Bagnall, Debate 1, Adolescent idiopathic scoliosis: Is the cause neuromuscular? The case for. In: Stokes IAF (ed.), In: Research into Spinal Deformities 2, pp 91-93. Amsterdam:IOS Press, 1999. K.M. Bagnall, Ligaments and muscles in adolescent idiopathic scoliosis. Spine:State of the Art Reviews 14(2):447-457, 2000. R.G. Burwell, P.H. Dangerfield, Adolescent idiopathic scoliosis: hypotheses of causation. Spine:State of the Art Reviews 14(2):319-333, 2000. D.J. Castle, K.A. Phillips (eds.), Disorders of Body Image, Petersfield UK & Philadelphia USA: Wrightson Biomedical Publishing Ltd, 2002. J. Cheng, Posterior tibial nerve somatosensory cortical evoked potentials in adolescent scoliosis. Spine 23:332-337,1998. C. Chiron et ai, Changes in regional cerebral blood flow during brain maturation in children and adolescents. Journal of Nuclear Medicine 33:696-703, 1992. H.T. Chugani et ai. Positron emission tomography study of human brain functional development. Annals of Neurology, 22:487-497, 1987. A. Cohen, Personal communication, 2002. A. Dalmau et ai, Somatic morbidity in schizophrenia - a case control study. Public Health lll(6):393-397, 1997. A. Dietrich, W. Been, Memory and DNA. Journal of theoretical Biology 208, 145-149, 2001. J. Dubousset, Les scolioses dites idiopathiques. Definition, pathologic, classification, etiologie. Bulletin Academic Nationale de Medicin 4:699-704, 1999. M. Edgar, Neural mechanisms in the etiology of idiopathic scoliosis. Spine: State of the Art Reviews 14(2):459-468, 2000. I. Feinberg, Schizophrenia: caused by a fault in programmed synaptic elimination during adolescence. Journal of psychiatric research 17(4): 319-334, 1982/3. B. Furlow, You must remember: how do we hold onto memories for a lifetime? Could our histories be inscribed in our genes? New Scientist, No 2308, 15 September, 2001. C.J. Goldberg, Debate 1, Adolescent idiopathic scoliosis:Is the cause neuromuscular? The case against. In:Stokes IAF (ed,). In: Research into Spinal Deformities 2, pp 94-97. AmsterdanrlOS Press, 1999. V.S Gurfinkel, Y.S. Levick, Perceptual and automatic aspects of the postural body scheme. In, Brain and Space, J Paillard (ed.) pp 147-162, 1991. H. Head, G. Holmes, Sensory disturbances from cerebral lesions. Brain 34: 102-244, 1911. D. Horrobin, The Madness of Adam and Eve. London: Bantam Press, 2001. P.R. Huttenlocher, Synaptic density in human frontal cortex - developmental changes and effects of aging. Brain Research 163:195-205, 1979. P.R. Huttenlocher, Synaptogenesis in human visual cortex - evidence for synapse elimination during normal development. Neuroscience Letters 33:247-252, 1982. P.R. Huttenlocher, Synaptogenesis in human cerebral cortex. In, G. Dawson, K.W. Fischer (eds.). Human Behaviour and the Developing Brain, pp 137-152, New York; Guilford. J. Kaiser, J.H. Gruzelier, Timing of puberty and EEG coherence during photic stimulation. International Journal of Psychphysiology 21: 135-149, 1996. M. Machida, Cause of idiopathic scoliosis. Spine 24(24):2576-2583, 2000. T.H. McGlashan, R.E. Hoffman, Schizophrenia as a disorder of developmentally reduced synaptic connectivity. Archives of General Psychiatry 57(7):637-648, 2000. J. Paillard (ed.), Brain and Space, Oxford University Press, 1991.

R.G. Burwell and P.M. Dangerfield/Etiologic Theories of Idiopathic Scoliosis

27. 28. 29. 30.

31. 32.

33. 34. 35.

36.

19

S. Pe_a de Ortiz, Y. Arshavsky, DNA recombination as a possible mechanism in declarative memory: ahypothesrs. Journal ofNeuroscience Research 63, 72-81,2001. A. Pfeifferbaum et al, A quantitative magnetic resonance imaging study of changes in brain morphology from infancy to late adulthood. Archives of Neurology 51: 874-887,1994. D. Purves, J.W.Lichtman, Elimination of synapses in the developing nervous system. Science 210: 153-157,1980. D. Purves, G.J. Augustine, D. Fitzpatrick, L.C. Katz, A-S Lamantia, J.O. McNamara, S.M. Williams (eds.), Chapter 25, Plasticity of mature synapses and circuits, pp 535-562, In, Neuroscience, Second Edition, Sunderland Massachusetts: Sinauer Associates Inc., 2001. L.F. Saugstad, Age at puberty and mental illness: towards a neurological aetiology of Kraepelin's endogenous psychoses. British Journal of Psychiatry 155: 536-544, 1989. A. Shumway-Cook, M.H. Woollacott, Motor Control: Theory and Practical Applications. Second Edition, Chapter 8, Development of Postural Control, pp 192-221, Philadelphia: Lippincott Williams &Wilkins,2001. A. Sirigu et al., Multiple representations contribute to body knowledge processing: evidence from a case of autotpagnosia. Brain 114: 629-642, 1991. T.K.F. Taylor, The brain stem and adolescent idiopathic scoliosis: a hypothesis. Spine:State of the Art Reviews 14(2):477-481,2000. A.G. Veldhuizen et al., The aetiology of idiopathic scoliosis: biomechanical and neuromuscular factors. European Spine Journal 9(3):178-184,2000. scoliosis. European Spine Journal 8(4):252-260,1999. J.B. Williamson, Postural control. Spine:State of the Art Reviews 14(2):469-476

Th.R. Grna.slEd.i Research into Spinal Deformities 4 IOS Press. 2H()2

Study of the rib cage deformity in children with 10°-20° of Cobb angle Late Onset Idiopathic Scoliosis, using Rib-Vertebra Angles Aetiologic implications Theodores B Grivas, Panagiotis Samelis, Theodores Chadziargiropoulos, Basilios Polyzois Scoliosis Clinic, Orthopaedic Department, "Thriasio" General Hospital G. Genimata Avenue, Magula, 19600 Greece E-mail: [email protected] Abstract. The aim of the study is to compare the rib-vertebra angles (RVAs) between children with 10° - 20° of Cobb angle late onset idiopathic scoliosis (LOIS) and non-scoliotic children. Materials and Method: The RVAs of 47 children, with mean age 12.4 years, who presented LOIS with a Cobb angle 10° - 20°, were studied. The children were classified into three groups according to the site of the scoliotic curve: 17 children had thoracic (T), 14 children had thoracolumbar (TL) and 16 children had lumbar (L) curves. The RVAs of the scoliotic children were compared to the RVAs of 60 nonscoliotic children of a similar age group, who were studied in the past. Results: The comparison of the right and left RVAs within each group showed that the children who had: T curves differ at the level T4, T5, T6, T7 and T8, TL curves differ at the level T3, and L curves differ at the level T7 and T12. The comparison of the ipsilateral RVA's between the scoliotic groups showed that between: T and TL curves there are no differences at any thoracic level, between T and L curves the RVAs differ at the T7 level on the right side, whereas mere are no differences between the RVAs on the left side, between TL and L curves the RVAs differ at the level TS, T6, and T7 on the right and at the level TS on the left side. Comparing the RVAs between the scoliotic and nonscoliotic children, it was apparent that the scoliotic children rib cage had lower RVAs (p 7°. The statistical analysis showed no difference of the age between the boys and girls, thus the studied sample contains homogenous aged population, (independent Samples T-test). The children were separated in the following groups: 1) with straight spine, 2) with curves measuring Cobb angle less than 10°, which is not considered as scoliosis according to SRS, 3) in children with i) thoracic ii) thoracolumbar and iii) lumbar curves. 2.2 The measurements. The Cobb angle was assessed on the standing posteroanterior and the segmental LSP, on the lateral spinal radiographs. The LSP was measured as following: A line was drawn down the posterior surface of each vertebral body from Tl to L5 on lateral standing radiographs, and the angle of this line from the vertical was recorded [8]. Intervertebral LSP values, that is the result of two successive LSP level values subtraction, were also calculated. When measuring the LSP, the forward tilt of a vertebra from the vertical is conventionally termed proclivity and it is deemed positively (+), while the backward tilt of a vertebra against the vertical is termed declivity and is deemed negatively (-) [8]. There are three component angles of sagittal spinal curves - upper proclive, declive and lower proclive angles. The kyphosis angle is a compound measure of sagittal shape - declive angle plus upper proclive angle. The lordosis angle is a compound measure of declive angle and lower proclive angle [2,3]. The point where the upper proclive angle is turned into the declive angle is considered as the first transitional zone of the LSP of the thoracic kyphosis, while the second transitional zone is located at the lumbar or lumbrosacral spine, where the declive angle is turned into the lower proclive angle. 2.3 The statistical analysis. The techniques used included frequencies, descriptives, Kruskal-Wallis test, Pearson Correlation Coefficient and independent Samples T-test, (SPSS). 3. Results The LSP is presented in the following groups of children: 1) with straight spine, 2) with curves measuring Cobb angle less than 10°, which is not considered as scoliosis according to SRS, 3) in children with i) thoracic ii) thoracolumbar and iii) lumbar curves. Statistics (independent Samples T-test) showed that segmental LSP do not differ between boys and girls of the examined population apart from T10; thereby the findings for both sexes are reported together.

T.B. Grivas et al. /Lateral Spinal Profile in School-Screening Referrals

27

Figure 1. The Lateral Spinal Profile for the various groups of children, boys and girls. Yellow bars = thoracic curves, azure bars = Thoracolumbar curves, mauve bars = lumbar curves, line with blue diamonds = straight spines, line with red rectangles = curves with Cobb < 10 dergees.

In the first group (straight spines) 27 children were included, 12 boys [44.4%] and 15 girls [55.6%]. The mean kyphosis (the T4 - T12 Cobb angle reading on lateral spinal radiographs) is 27.1 degrees, and the mean lordosis 30.3 dergrees, (the LI - L5 Cobb angle reading on lateral spinal radiographs). In the second group (curves with a Cobb angle of less than 10°), 13 children were included, 6 boys [46.2%] and 7 girls [53.8%]. The mean kyphosis was 24°, and the mean lordosis 30°. In the third group of children with: i) Thoracic curves with a Cobb angle 10° -20°, 47 children were included, 17 boys [36,2%] and 30 girls [63.8%]. The mean kyphosis was 31°, and the mean lordosis 35.8°. ii) Thoracolumbar curves with a Cobb angle of 10° -20°, 14 children were included (4 boys [28.6%] and 10 girls [71.4%]. The mean kyphosis was 28° and the mean lordosis 32.2°. iii) Lumbar curves with a Cobb angle of 10°-20°, 28 children were included, 7 boys [25%] and 21 girls [75%]. The mean kyphosis was 28.7°, and the mean lordosis 32.6°. The statistical analysis of the LSP's of children with thoracic, thoracolumbar and lumbar curves, using the Kruskal-Wallis non-parametric test, showed no differences among them, apart from L2 and L3 spinal levels and only for girls. Comparing the children's LSP between groups, using Mann-Whitney test, it was shown that: Between the first (straight spines) and the second group (0° -9° Cobb angle), no statistical difference was noticed. Between foe first and the third group with thoracic curves, a difference was found on the T6 level, (p< 0.05). Between the first and the third group with thoracolumbar curves, a difference was found on the L3 level, (p< 0.02). Between the first and the third group with lumbar curves, a difference was shown on the

T.B. Grivas et al. /lateral Spinal Profile in School-Screening Referrals

T4 and L2 level, (p< 0.04 and p< 0.03 respectively). Between the second group of children and the third group with thoracic curves, a statistical difference was shown on the spinal levels T4, (p< 0.02), L2 (p< 0.048) and L3 (p< 0.035). Between the second group and the third group with thoracolumbar curves, a difference was found on the L2 (p< 0.027) and L3 (p< 0.018), spinal levels. Between the second group of children and the third group with lumbar curves, a difference was found on the T4 and L2 spinal levels, (p< 0.04 and p< 0.017 respectively). From the above comparisons it is ascertained that some distinct differences are focused mainly at the lumbar spine. The spinal levels where the first and the second transitional zone appears, relating to the inclination of the LSP (proclive - declive angle) and the maximum value of the above angles are presented in Table 1. In the children of the first group the declive angle from T5-T6 to the T12-L1 is greater than that in the remaining groups of children. The children of the third group, were presenting declive angles from L1-L2-L3 greater than the non-scoliotics, (first and second group), in the contrary at T5-T6 to T12 the declive angle was smaller than in the non-scoliotics. Table 1 Groups of children

First transitional zone * Spinal level

First group Second group (Curves < 10-€ Cobb) Third group Thoracic curves Third group Thoracolumbar curves

T5-T6 T6-T7

Spinal level and maximum value of declive angle TI2(-20.4°) T12 (-18.46°)

Second transitional zone** Spinal level L3-L4 L3-L4

Spinal level and maximum value of proclive angle L5(14-) L5(I5')

T6-T7

TI2 (-20.7°)

L4-L5

L5(165°)

T6-T7

T12(-20.0°)

L4-L5

L5(15.7°)

T12(-I8.7°) L3-L4 T6-T7 L5(16.510° curves. Material and Method: 3631 screened children where divided in 3 groups. The 1st group comprised normal children with 0° angle of trunk inclination, (ATI). The 2nd group comprised children with ATI >1° and < 6°. The third group comprised children with ATI >7° and Cobb angle >10°. The mean/median and standard deviation (± 1 SD) of body weight and height, the body mass index (BMI = weight/height2) and the corrected for the scoliotic curve height were calculated by age. Statistical analysis included descriptives (mean, ± 1 SD, median) and Mann - Whitney non-parametric test. Results: In boys of the 1st and 2nd group 4,25% had obesity (BMI = 30-35), 2,9% severe obesity (BMI = 30-35) and 1,7% morbid obesity (BMI = 40-45)- while 6,4%, 1,9% and 1,3% in girls respectively. In the 3rd group girls, 27,2% were underweight (BMI = 16-20) and 11,3% severely underweight (BMI < 16), while among boys 42% were severely underweight. In the 3rd group there were no obese girls and only 5% obese boys. The comparison of body weight between scoliotic (3rd group) and nonscoliotic children (1st and 2nd group) fails to show any statistical difference. In the 1st and 2nd group, the girls' mean height is greater than that of boys aged 9-12 years but less when boys are 13-18 years old. In the 3rd group a mean of 1,15 cm increase is observed after height correction for the scoliotic curve, in boys and 1,3 cm in girls respectively. The comparison of body height (both uncorrected and corrected) between scoliotic and nonscoliotic children fails to show any statistical difference. Discussion-Conclusions: A variety of findings regarding the stature and weight of AIS children has been published. In this studied Mediterranean sample of the population, the somatometric parameters of height and weight in children with scoliosis, regardless of curve type and site, are not statistically different from their nonscoliotic counterparts.

1. Introduction The somatometric parameters body weight and height are directly associated with the child's growth. Since idiopathic scoliosis is a deformity which develops mainly during growth, the above somatometric parameters are potentially related to this deformity. The progression of growth across the various geographical regions is not similar. Therefore, the study of body weight and height in healthy and scoliotic Mediterranean children may be interesting.

4S

T.R. Gnvas ct til. /Comparison of Rod\ Weight and Height

The aim of this report is the formation of a database with somatometric parameters (body weight and height) from school screening children and the comparison of the same somatometric parameters of non-scoliotic children with these of their counterparts suffering scoliosis with a Cobb angle of >10° curves.

2. Material and Method 2.1 The examined children. 3631 children, 1809 girls and 1822 boys, screened for scoliosis were included in the study. The children were divided into three groups. The 1st group comprised 1592 healthy children, 836 boys and 756 girls, with an 0 angle of trunk inclination, (ATI). The 2nd group comprised 1592 children, 1009 girls and 967 boys, with ATI >1° and < 6 °. The 3rd group comprised 63 scoliotics, 19 boys and 44 girls, with a ATI >7 and a Cobb angle of >10°. Subsequently the children of each group were sorted by age and sex. 2.2 The measurements. The mean body height, and weight with standard deviation (±1SD) and median was calculated for each of the above subgroups of children. The body mass index (BMI) was also measured as body weight divided by height2. The corrected for the curve height of the scoliotics was also calculated using the Bjureand Nachemson 1973,formulam: Logi0y = 0,011x- 0,177 where y is the body height loss in cm and " the Cobb angle of the major scoliotic curve. The stature meter for measurement of the standing height in cm and a scale with 0.5 Kg increments for the body weight was also used. The children were divided in relation to their weight according to Bray and Metropolitan Life Insurance classification as follows: BMI < 16 severe under-weight children, BMI 16-20 under-weight children, BMI 20-25 normal children, BMI 25-30 overweight children, BMI 30-35 obese children, BMI 35-40 severe obese children, BMI 40-45 morbid obese children, BMI > 50 severe morbid obese children. 2.3 The statistical analysis. The techniques used included frequencies, descriptives, (mean, ± SD, Median), Kruskal-Wallis test, Pearson Correlation Coefficient and independent Samples T-test, (SPSS).

3. Results A. Height. In the 1st group, figure 1, the girls' mean height is larger in 9-14 years of age. The boys' mean height is larger in 14 years, and after this age the difference is statistically significant. In the 2nd group, figure 2, the girls' mean height is larger in 10-13 years of age. The boys' mean height is larger following the age of 13 years with a statistically significant difference.

T.B. Grivas et al. / Comparison of Body Weight and Height

49

In the 3rd group, figure 3, the mean corrected height is larger for girls in 12-13 years of age compared with the boys matched for age, but this difference is not statistically significant. Comparing the girls' height in the three groups, it is noticed that scoliotics are taller but not significantly so than the healthy counterparts, figure 4. The same is also noticed for the scoliotic boys, figure 5. An increase of 1,15 cm is noticed in the mean height of the scoliotic boys and 1,3 cm of the scoliotic girls respectively, after the correction of the height for the curve. It is also interesting to note that there is no statistically significant difference for the height (nor for the corrected one) among scoliotics and the healthy groups (1,2) of children by age. B. Weight. It is shown that in the 1st group, figure 6, the girls' mean weight in 9-12 years of age is arithmetically larger than this of boys but not statistically different, while boys' mean weight is statistically larger from the age of 14 years and afterwards. In the 2nd group, figure 7, the girls mean weight, from the age of 8 to 12 years, is arithmetically larger than this of boys but not statistically different, while boys' mean weight from the age of 14 years and afterwards is statistically larger than this of the girls. Comparing the girl's weight in the three groups, figure 8, it is noticed that from the age of 8-12 years, scoliotics are heavier compared to their non-scoliotic counterparts but are thinner after the age of 13. Studying the BMI of the non-scoliotic boys it is shown that 4,25% are obese, 2,9% severe obese and 1,7% morbid obese. Similarly, for the non-scoliotic girls it is shown that 6,4% are obese, 1,9% severe obese and 1,3% morbid obese. The majority of scoliotics have normal BMI and there is no record of obese scoliotic girl in the study population. 4. Discussion Studying the height, it was found that scoliotic girls are taller compared to healthy counterparts, Willner 1974p41. On the contrary Duval-BaupereI8] did not report any height difference between scoliotics and healthy children. Buric et al, 1982t4', reported that scoliotic are 5 cm taller than the healthy girls in the studying population, but there was no difference in the weight between them. Dickson and Sevitt, 1982[7], in Britain and Leong et al, 1982, in south China, reported that AIS girls are taller compared to findings for girls from recent studies. Archer and Dickson, 1985[1], reported that the mean girls height suffering AIS with curves measuring Cobb angle > 15 , were significantly larger from the mean height of girls with curves measuring Cobb angle :£ 15 . Carr et al, 1989I5], found that scoliotics have a loss of height from 0 to 5,3 cm (mean 2,2 cm), when the estimation of height loss is based on the severity of the lateral curve of the spine and the kyphosis /lordosis. The formula they use to estimate the height loss in scoliotics is: CLS + (SSL - SSL normal). They used ISIS for curve assessment. When their measurements were compared to the height loss due to the curve using Bjure - Nachemson' s 1986131,

T.B. Grivas ct al. / Comparison of Body Weight and Hcis>hr

formula, it was found that the height loss was significantly smaller when ISIS was used for curve assessment. Miraloncar-Dusek et al, 1991^16', showed that scoliotic girls presented higher growth spurt (8,1 cm per year) compared to the healthy girls (7,1 cm per year). They showed a similar growth pattern for boys respectively. Nikolopoulos et al 19851' , reported that the scoliotics standing height is significantly increased compared with healthy girls. Goldberg et al 1993[91, found that scoliotic girls are taller when they are younger while there was no difference in adolescence. This findings are alike to these of Nordwall and Willner 1975fl9), namely there is an auxesis in scoliotics height only in younger age. According to Goldberg's findings the increased height observed in younger scoliotic children is due to the early adolescent growth spur of these girls with late commencement of IS. This theory is supported by the fact that the mean menarch age was significantly lower compared with the relevant national mean age. Grivas et al 19991'1', reported no difference of the menarch age for the scoliotics and the non scoliotic counterparts, using Mediterranean school screening population. It has been reported that in AIS boys and girls BMI is normal before the development of scoliosis, Nissinen et al 1993fl8], and it is decreased during the maturation, Shohat et al 198812'1. Cole et al'61 found that AIS girls show an increase in all their anthropometric parameters compared to their normal counterparts except in the thorax, where the lateral thoracic diameter is significantly different from normal. The mean stature growth in the preoperative AIS girls is constant, as is reported elsewhere too. Grivas, 19841'0*, reported that the healthy girls of 12 years of age are at average taller and heavier than their counterparts. Tsanakas et al 1985f 31, using BMI found that in a Greek study population, the obesity percentage for boys is almost constant in all the ages, while in girls it is increased significantly by the age. The same was shown by Bitsioris et al 1995'2' studying a population in Crete island. Mazagrioti et al 1986'15', documenting the national growth patterns, reported that boys show greater growth velocity from the age of 6 to 10,3 years. From the age of 10,3 and then, this pattern is changing and girls present a greater value of this variable of 0,7 cm compared to boys. From 12,3 years of-age when girls have attained their maximum of growth spurt, a gradual decrease in this difference is commencing so that at the age of 13 years boys are taller than girls. They also observed an obesity tendency in both sexes in all ages, which is stronger for girls. Kapetanoset al 20001'3', reported a significant difference in height between scoliotics and non-scoliotics, but he did not take into account the height loss due to the curve. It is reported that thin children are more susceptible to develop scoliosis at a percentage of 9%, while in fat children the percentage is 4% (Smymis et al 1979t22], Kapetanos et al 1986(12J). A variety of findings regarding the stature and weight of AIS children has been published. As it appears in this studied Mediterranean sample of population, the somatometric parameters of height and weight in children with scoliosis, regardless of curve type and site, are not statistically different from their nonscoliotic counterparts. These findings are in accordance to DuvalBeaupere [8] findings. Coldgerg et al 1993[9], and Willner 19751251, reported that stature development is independent from the severity of the curve. Normelli et al 1985'20', found that girls with thoracolumbar and double major curves are taller at menarch compared to girls suffering from right thoracic curves. It must be mentioned that variables as severity, type and site of the curve and the age at diagnosis of scoliosis are not defined in this study population.

T.B. Grivas et al. / Comparison of Bod\ Weight and Height

51

References 1. 2.

3. 4. 5. 6.

7. 8. 9. 10. 11.

12. 13.

14. 15. 16.

17. 18. 19. 20. 21. 22. 23. 24.

Archer IA, Dickson RA, Stature and idiopathic scoliosis, a prospective study. J Bone Joint Surg, 67B, 185-188, 1985. Bitsori M, Nearchou A, Kazmatzi B, Malathraki M, Kolidaki-Spiridaki M, Rebalakis B, Kafatos A, Kounali D, Kalafatis A. Growth and dietary habits of school age children in the region of Sitia. Paediatriki, 58: 326-335, 1995. Bjure J, Nachemson A: Non-treated scoliosis. Clin. Orthop. 93: 44-52, 1973. Buric M, Momcilovic B: Growth pattern and skeletal age in schoolgirls with idiopathic scoliosis. Clin Orthop 170: 238-242, 1982. Carr AJ, Jefferson RJ, Weiss I, Turner-Smith AR. Correction of Body Height in Scoliotic Patients Using ISIS Scanning. Spine 14: 2, 207-209, 1989. Cole AA, Burwell RG, Dangerfield PH, Grivas TB, Webb JK, Moulton A. Adolescent Idiopathic Scoliosis: Anthropometry. In State of the Art Reviews 2000 (STAR), Hanly and Belfus Inc, 210 South 13th Street, State of the Art Review, Etiology of the Adolescent Idiopathic Scoliosis, RG Burwell, PH Dangerfield, TG Lowe, JYMargulies, (eds). Vol 14(2) May 2000. Dickson RA and Sevitt EA Growth and idiopathic scoliosis: a longitudinal cohort study. J Bone Joint Surg. 64-B, 385, 1982. Duval-Baupere G: Pathogenic relationship between scoliosis and growth. In Zorab PA (ed): Proceedings of a Third Symposium London, Churchill Livingstone, 1971 pp. 58-64. Goldberg GJ, Dowling FE, Fogarty EE, Adolescent Idiopathic Scoliosis- Early Menarche, Normal Growth. Spine 18: 5, 529-535, 1993. Grivas TB: " Survey for the lower limbs of early school age children". MD Theses, University of Athens, Greece, 1984. Grivas TB, Samel is P, Pappa AS, Stavlas P, Polyzois D. Menarche in Scoliotic and Nonscoliotic Mediterranean Girls. Is There Any Relation between Menarche and Laterality of Scoliotic Curves? 2000 Meeting of the International Research Society of Spinal Deformities. Clermont, France, 23-26 May 2000, p.7. In: Research into spinal deformities 3, Peuchot B, Tanguy A (Eds), IOS Press, Amsterdam 2001, in press. Kapetanos G, Pournaras J, Christophoridis J, Pacharliotis A, Symeonidis P. Scoliosis in northern Greece. Proceedings of the Northern-Greece Medical Meeting Volume B, 1986. Kapetanos G: School screening in Macedonia, (Northern Greece). In: Grivas TB (ed): School screening for Scoliosis, Athens Paschalides Medical Publications, 2000, ISBN 960-7398-74-2, pp 47-53. Leong JC et al: Linear growth in southern Chinese female patients with adolescent idiopathic scoliosis. Spine 7, 471-475, 1982. Mantzagrioti-Meimarides M, Pandazides N, Doxiades S, Raphael M. "National growth Standards. Height and weight for children and adolescent Greek population". Paediatriki 49: 1-15, 1986. Mira Loncar-Dusek, Marko Pecina, Zivka Prebeg. A longitudinal study of Growth, Velocity and Development of Secontary Gender Characteristics Versus Onset of Idiopathic Scoliosis. Clin Orthop, 270, 278-282, 1991. Nicolopoulos KS, Burwell RG, Webb JK. Stature and its components in Adolescent Idiopathic Scoliosis, J Bone Joint Surg, 67-B: 594-601, 1985. Nissinen M et al: Trunk asymmetry, posture, growth, and risk of scoliosis. A three-year follow-up of Finnish prepubertal school children, Spine 18:8-13,1993. Nordwall A, Willner S, A study of skeletal age and height in girls with idiopathic scoliosis, Clin. Orthop. 110, 6-10, 1975. Normelli H et al : Anthropometric data relating to normal and scoliotic Scandinavian girls. Spine 10:123-126,1985. Shohat M. et al: Growth and ethnicity in scoliosis. Acta Orthop Scand 59: 310-313, 1988. Smyrnis P, Balavanis I, Alexopoulos A, Siderakis G, Gianestras N, School screening for scoliosis in Athens. J Bone Joint Surg, 61-B, 215-217, 1977. Tsanakas JN, Roilides EJ, Hatzimichaei A, Thodis S, Varlanis P, Karpouzas J: The significance of screening in schoolchildren's health care". Paediatriki 49:154-164, 1986. Willner S: A study of growth in girls with adolescent idiopathic structural scoliosis. Clin Orthop 101: 129-135, 1974.

T.H. (rrh'tif el dl. / Comparison of Htxh Weight and Height

25

Willner S: A study of height, weight and menarche in girls with idiopathic structural scoliosis. Ada OrthopScand 46:71-83, 1975.

of boy. Iglrto MgM to tfc» 1i» gn>w

•parim **•*• kngkl mrtwAnt

-f»fr

Figure 1: Comparison of boys and girls height in the Isr group. (Line with blue circle represents boys, with red triangle represents girls).

Figure 4: Comparison of girls' height in the three groups. (Line with blue diamonds represents group 1, with red triangle represents group 2. and with black rectangle represents group 3).

Figure 2: Comparison of boys and girls height in the 2sr group. (Line with blue circle represents boys, with red triangle represents girls).

Figure S: Comparison of boys' height in the three groups. (Line with blue circle represents group I, with red rectangle represents group 2, and with black triangle represents group 3).

Figure 3: Comparison of boys' and girls' corrected height in the 3rd group. (Line with blue circle represents boys, with red triangle represents girls).

Figure 6: Comparison of boys' \ girls' weight in the 1" group, (boys weight is represented by the line with blue diamonds, girls with red triangle respectively).

T.B. Grivas et al. / Comparison of Body Weight and Height

Comparison of boy» \ girls weight in the 2nd group

Figure 7: Comparison of boys' \ girls' weight in the 2 group, (boys weight is represented by the line with blue diamonds, girls with red triangle respectively).

53

Comparison of gire body wvight among UM thrM group*

Figure 8: Comparison of girls' weight among the three groups. (Line with blue diamond represents group 1, with red rectangle represents group 2, and with black triangle represents group 3).

54

Th.B. Gnvas(Ed.i Research into Spinal Deformities 4 IOS /Vrvs. 22

Evolution of 3D Deformities in Adolescents with Progressive Idiopathic Scoliosis I. Villemure1'3, C.-E Aubin2 3, G. Grimard1J, J. Dansereau2'3, H. Labelle 13 1- Universite de Montreal/2- Ecole Polytechnique de Montreal, POBox 6079, Station Centre-ville, MontrealH3C3A7, Canada 3-Research Center, Ste-Justine Hospital 3175 Cote Ste-Catherine Rd, Montreal, Canada Abstract. The objective of this study was to conduct an intrasubject longitudinal study quantifying the evolution of two- and three-dimensional geometrical scoliotic descriptors. The evolution of regional and local scoliotic descriptors was analyzed between two scoliotic visits on a cohort of 28 adolescents with progressive idiopathic scoliosis. Mean age at the first visit was 12.711.7 years old and averaged time interval between two assessments reached 22.8±10.8 months. Scoliotic descriptors were obtained from three-dimensionally reconstructed spines. The initial thoracic Cobb angle was on average 35.3°±8.4° (range, 14°-54°). The evolution of spinal curvatures and vertebral deformities was assessed statistically in terms of descriptor absolute variations, and of descriptor variations normalized with respect to time and to the increase in Cobb angle. At the thoracic level, vertebral wedging increased with curve severity in a relatively consistent pattern for most scoliotic patients and axial rotation mainly increased towards curve convexity with scoliosis severity. No consistent evolution was associated with the angular orientation of the maximum wedging. Thoracic kyphosis changes (increase and decrease) were observed in important proportions. Results of this study challenge the existence of a typical scoliotic evolution pattern and suggest that the scoliotic evolution is quite variable and patient-specific.

1. Introduction and objectives The development of adolescent idiopathic scoliosis (AIS) has been investigated using geometrical descriptors to quantify curvatures (regional scale) and intrinsic alterations of vertebral and intervertebral tissues (local scale). Evaluation of geometric descriptors is usually mainly reported in cross-sectional intersubject studies comparing configurations of different individuals. Some of these studies investigated 2D and 3D relationships between regional and local scoliotic deformities [1,2,3]. The literature reports that at the thoracic level scoliosis severity is associated with a "coronalization" of the plane of maximum deformity, an increasing vertebral wedging and an axial rotation evolving towards the curve convexity. Notwithstanding the potential individuality involved in scoliotic progression, the literature reports very few longitudinal studies evaluating different phases of progression for the same individual. The objective of this study was to carry out an intra-subject longitudinal study quantifying evolution of 2D and 3D geometrical descriptors in order to provide complementary information on the progression of adolescent idiopathic scoliosis.

/. Villemure et al. /Evolution of 3D Deformities in Adolescents

55

2. Material and Methods 2.1 Evaluation of regional and local descriptors Descriptors were evaluated analytically from 3D reconstructed spines of scoliotic subjects using a multiview radiographic technique based on calibrated PA and lateral X-rays [4]. For each vertebra, six anatomical landmarks were digitized on both X-rays and reconstructed in 3D using the Direct Linear Transform algorithm [4]. Eight additional noncorresponding points on the vertebral body extremities were used within an iterative procedure fitting 3D oriented ellipses of adequate diameters on both vertebral endplates [5]. The regional descriptors included (Fig.l): 1) the frontal Cobb angle in the global postero-anterior (PA) plane of the subject (Cobb); 2) the Cobb angle, confined by the same end vertebrae of the curve, projected in the plane of maximum deformity (CobbMax); 3) the angular orientation of the plane of maximum deformity with respect to the global sagittal plane of the subject (9 Max); 4) the thoracic kyphosis (Kt) measured using the Cobb method to describe the sagittal profile. The local descriptors included (Fig.2): 1) the maximum 3D wedging angle (oo 30), corresponding to the real 3D inclination magnitude (i.e. maximum) between two adjacent ellipses; 2) the angular orientation of the line joining the maximum and the minimum heights of the vertebral body with respect to the local sagittal plane of the vertebra (6 ^D); 3) the vertebral axial rotation (9 z), defined as the angle between the vertebral and global frontal planes when projected in an auxiliary plane perpendicular to the vertebral body axis (viewed from above, clockwise axial rotation is measured as negative).

Fig.l Regional scoliotic descriptors

Fig.2 Local scoliotic descriptors

2.2 Clinical investigation This study involved AIS thoracic curves developed in right thoracic (12 RT) and right thoracic left lumbar (16 RTLL) curve types. Adolescents (27 females; 1 male) were recruited based on a criterion of scoliosis progression defined as a minimum increase of 5°/year of the Cobb angle in the frontal plane (Cobb). Two visits were considered for each subject. Mean age at the first visit reached 12.7±1.7 years old and averaged time interval between two assessments was 22.8±10.8 months. The overall scoliosis severity as measured by the initial thoracic Cobb angle was on average 35.3°± 8.4° (range, 14°-54°). Regional descriptors were evaluated on the thoracic segment while local descriptors were computed on the thoracic apical vertebra. Absolute descriptor variations between two visits (AD for descriptor D) as well as descriptor variations normalized with respect to time (AD/At) and to the increase in scoliosis severity (AD/ACobb) were investigated to characterize the evolution of scoliotic deformities. Subjects were partitioned with respect to the pattern in the absolute variations of the descriptor (AD>0 or ADf 3D Deformities in Adolescents

3. Results Overall, a mean increase in Cobb angle of 16.1°±9.0° (from 35.3°±8.4° to 51.4°±8.5°) was found between two assessments, and translated an average progression of 8.8°±3.4° per year (Table I). The corresponding Cobb angle in the plane of maximum deformity (CobbMax) was slightly higher compared to the Cobb angle in the frontal plane, but resulted in a similar curvature progression (15.9°±9.7°) (Table I). Slightly greater increases were found in the normalized variations of Cobbm.x, with an average yearly progression of 9.2°±5.8°, and a mean increase of 1.05°±0.64° per degree of Cobb progression (Table I). The spinal curves in the plane of maximum deformity (Cobbmax) increased for all subjects (Fig.3). The angular orientation of the plane of maximum deformity 6 Max invariably remained in the right postero-lateral side of the subject (Table I), with this plane mostly evolving towards the frontal plane (in 71% of the subjects) (Fig.3). Corresponding normalized variations indicated an average yearly evolution of 3.0°±4.6° of this plane towards the frontal plane as well as a displacement of 0.42°±0.65° per degree of curve increase (Table I). The mean kyphosis (about 30°) was similar throughout the studied period (Table I), with most subjects having a kyphosis that increased with scoliosis (in 64% of the subjects) (Fig.3). The normalized variations of kyphosis also showed considerable variability, with relatively high standard deviations (Table I). Table 1. Statistics for descriptors and their variations between scoliotic visits. Proportions of subjects (%) as partitioned in positive and negative absolute variations of descriptors AD (e.g. counterclockwise axial rotation 6 z for 18%, and implicitly, clockwise axial rotation 6 z for 82 % of the cases).

Average variations in apical wedging was 5.1°±4.2° (co 30) over two visits (Table I), with increasing trend in 93% of the cases (Fig.3). Corresponding normalized variations indicated a mean yearly increase of 2.6°±2.0°, with a wedging increase of 0.31°±0.24° per degree of curve progression (Table I). Angular orientations 6 ,,30 were consistently located in the right lateral quadrant of the vertebra (Table I), but they showed variable evolutions (Fig.3). Correspondingly, the normalized variations indicated non-negligible variability with relatively high standard deviations (Table I). An average axial rotation of 7.8°±8.4° clockwise was obtained (Table I), indicating that the vertebral body is rotating towards the convexity of the curve. The vertebral axial rotation showed significant aggravating trend in 82% of the cases (Fig.3). This translated in an average clockwise rotation of 5.3°±8.2° per year and a clockwise increase of 0.60°±0.78° per degree of Cobb (Table I).

/. Villemure et al. /Evolution of 3D Deformities in Adolescents

Figure 3. Diagram presenting proportions of subjects (%) as partitioned in positive and negative absolute descriptor variations (e.g. clockwise axial rotation 9 z for 82% of the cases). Table 2. Correlations between absolute variations of regional and local scoliotic descriptors. A(K.)

A(Cobb)

ACCobbftb.)

A()

p = 0.91

p < 0.001

p = 0.02

A(e^,)

p = 0.91

p = 0.66

p = 0.58

p = 0.43

A(60

p = 0.36

p = 0.78

p = 0.75

p = 0.19

Aie.to)

A 10° after SRS. The standing forward bending test was used. An Orthopaedic surgeon always participated in the scientific screening team. 215899 children aged 5.5 - 15 years were screened. When there was suspicion of scoliosis, the child was further assessed radiolographically (standing postero - anterior spinal radiographs), for Cobb angle appraisal. Results: In 130689 screened children, scoliosis was considered when the consequent radiological assessment revealed Cobb angle of > 10°, (a), and in 85210 children when it revealed Cobb angle of 2 5° respectively, (b). In (a) studies the scoliosis incidence was 2.9% (range 1.1 - 5.7%), and (b) 4.9% (range 2.7 - 9.5%) respectively. The right thoracic curves dominated in both (a) and (b) studies and thoraco - lumbar, lumbar and double curves followed. Among 7965 scoliotics out of the total sample of 215899 children, 4.5% were conservatively treated with the use of a brace, and only 0.19% was treated surgically. Conclusions: From data of 1998 national census, the population of children aged 8 to 14 years old was approximately 751000. With the above mentioned datum and with a national mean scoliosis incidence of 2.9%, (Cobb angle > 10°), 21781 children will be found with scoliosis. 980 will need conservative treatment using a brace while 41 children will need surgical treatment.

1.

Introduction

The importance of preventive medicine especially in children and adolescents is widely recognized. School screening is still the best and more effective method for the prevention of severe scoliosis deformities. School screening has been performed at various geographical departments of Greece. In this report the results of 17 School Screening programs are presented. The aim is to define the national scoliosis incidence, as well as the number of children who will need conservative or surgical treatment.

71

T.K. Gri\'os el til. /'The Incidence ofIdiopathic Scoliosis in Greece

2.

Material - Methods

The geography of the screening programs. From 1975 to 1999, 17 School screening programs were performed in various geographical departments of Greece. The regions where these programs were performed are more specifically mentioned, namely the area of Thriasion Pedion at the prefecture of Attika, the cities of Athens, of Patra in Peloponissos, of Thessaloniki in Macedonia, of Xanthi in Thracki, the Evia, Chios, Mitilini, Samos, Crete and the Aegean sea Islands, the Ionian Islands, the prefecture of Larissa at the geographical department of Thessalia, and the geographical departments of Epirus, Aitoloacamania and Hemathia. The regions that where mentioned before are presented in Table I, as well as the total number of children who where participated in the School screening programs. Table I: Blue circles shows the regions were school screening programs were performed, as well as the total number (n) of participated children. The percentage of scoliosis is reported in parenthesis. Scoliosis was defined when Cobb angle > 5° for the SS2IO examined children in some school screening programs. More recently and according to SRS, scoliosis is defined when the Cobb angle of a lateral spinal curvature is > 10°.

Athens n=3494 (5.7%, Cobb>10°), Evia n=9537 (9.5%, Cobb>5°), Chios n=4206 (3.6%, Cobb>5°), Mitilini n=5380 (4.1%, Cobb>5°), Samos n=2700 (5.46%, Cobb>10°), Thessalia n=38044 (1.1%, Cobb>10°), Larissa n=22148 (2.7%, Cobb>58), Epirus n=21415 (3.2%, Cobb>10°), Aitoloakarnania n=16743 (1.7%, Cobb>10°), Ionia Islands n=6699 (1.1%, Cobb>10°), Patra n=10000 (2%, Cobb>10°), Thessaloniki n=7658 (6.%%, Cobb>5°), Hemathia n=12490 (7.12%, Cobb>5°), Xanthi n=26612 (2.7%, Cobb>5°), Crete n=21220 (1.7%, Cobb>10°), "St Sofia" Hospital - Athens n=3922 (2%, Cobb>10°), Attica Thriasio Pedio n=3631, (2.9%, Cobb>10°).

T.B. Grivas et al. /The Incidence of Idiopathic Scoliosis in Greece

The examination team of each School screening program comprised of Orthopaedic Surgeons, Physical Therapists and Health Visitors. The leading persons of the examination team are the Orthopaedic Surgeons. The children. 215899, (107226 boys and 108673 girls), aged 5.5 to 15 years old were included in the study. The procedure of the clinical and radiological examination was common in all School Screening programs. The assessment methods. As a rule, the forward bending test (FBT) was used. The FBT was performed as follows: The children were instructed to bend forward, standing with feet together, knees straight and arms dependent and held with fingers and palms in opposition. In the School Screening program of Samos, Patra and Thriasion Pedion, a scoliometer was also used. The readings from the prominence of the back in the thoracic, thoracolumbar and lumbar region were analyzed. The radiographical evaluation, using the Cobb angle, was performed when needed. Definition of scoliosis. Traditionally scoliosis was defined when a lateral spinal curvature measured a Cobb angle of > 5° on a posteroanterior radiograph. This was applied for the 85210 examined children in some school screening programs. More recently and according to SRS, scoliosis is defined when the Cobb angle of a lateral spinal curvature is > 10°. This convention was applied for 130689 examined children. Publicity. All the Greek school screening programs were analyzed and the findings were published, among other chapters, in a 272 pages book, under the title: "School screening in Greece", Athens, Paschalidis Medical Publications, 2000, ISBN 960-7398-74-2. 3.

Results

In 130689 children scoliosis was counted when the Cobb angle was > 10° group (a), and in 85210 children when the Cobb angle was > 5° - group b. After 1986 under the guidelines of SRS, patients were considered scoliotic only when the Cobb angle was > 10°. In group (a) scoliosis was observed at a percentage of 2.9% (range 1.1-5.7%), while in group (b) 4.9% (range 2.7-9.5%) respectively. Regarding the scoliotic curve location, thoracic curves dominated in both (a) and (b) studies and thoracolumbar, lumbar and double curves followed in frequency. In Evia, Chios, Mitilini, Epirus, Thessaloniki and "Thriasion" the girls outnumbered the boys. The highest scoliosis percentage was observed in Evia, Samos and Thessaloniki. From 215899 children, 7965 were found to be scoliotic. From these, 4.5% (358 children) were treated conservatively with braces, while only 0.19% (15 children) underwent surgery. Approximately 90% of the referred children reported for examination at hospital. 4.

Discussion

This study presents the idiopathic scoliosis incidence in Greece, analyzing the data from 17 domestic School Screening programs. From data of the 1998 national census, the children population aged 8 to 14 years old numbered 751000. With the above - mentioned datum and with a national mean scoliosis incidence of 2.9%, (Cobb angle of > 10°), 21781 children will be diagnosed with idiopathic scoliosis.

4

T.B. Grivas a al. / The Incidence of Idiopathic Scoliosis in Greece

According to Stuart & Weinstein (2002) the treatment indications for Idiopathic Scoliosis are given in Table II. The treatment of each patient must be individualized, taking into consideration the probability of progression based on curve magnitude, skeletal maturity, sexual maturity, and age. Following these widely accepted treatment indications, 980 (4.04%) of our scoliotics will need conservative treatment using a brace while 41 (1.88%) children will need surgery. This incidence of patients requiring treatment is close to that reported by Stuart L. Weinstein, in Department of Orthopaedic Surgery at University of Iowa Hospitals and Clinics that is 1.0% for females and 0.1% for males. Table II: Treatment indications for Idiopathic Scoliosis in skeletal immature people

10° was 1.04%. Rogala et al reported the findings of school screening of 26947 Canadian children from 138 schools. They found 1231 students with structural scoliosis and 48 with nonstructural scoliosis, with an incidence of 4.7%. The incidence of idiopathic scoliosis of > 10° was 2%. The incidence of idiopathic scoliosis of > 10° in a screening study involving 21333 Japanese children was 1.75%. Finally, the incidence of idiopathic scoliosis reported around the world ranges from 1% to 12%, although the incidence of the deformity with Cobb angle of > 10°, resulting from screening programs, is approximately 2%. References 1. 2. 3. 4. 5. 6.

Brooks HL, Azen SP, Gerberg E, Brooks R, Chan L: Scoliosis: A Prospective Epidemiological Study. J Bone Joint Surg 57A: 968-972,1975. Chan A, Molier J, Vimpani G, Paterson D, Southwood R, Sutherland: The case of scoliosis screening in Australian adolescents. Med J Austl45: 379-383, 1986. Cronis S, Gleeson AW: Orthopedic screening of children in Delaware. Phys Ther 54:10801083, 1974. Korovesis PG: Observations made during school screening for scoliosis in Greece. Spine 23 (17): 1924, 1998. Koukourakis I, Giakourakis G, Kouvidis G, Kivernitakis E, Blazos J, and Koukourakis M: Screening school children for scoliosis on the island of Crete. J. Spinal Disord. 10(6): 527531, 1997. Liu, Shang-li and Huang, Dong-Sheng: Scoliosis in China: A General Review. Clinical Orthopaedics and Related Research 323: 113-118,1996.

T.B. Grivas el al. /The Incidence of Idiopaihic Scoliosis in Greece

7. 8. 9.

10. 11. 12.

13.

Lonstein JE, Bjorklund S, and Wanminger MH, Nelson RP: Voluntary school screening for scoliosis in Minnesota. J Bone Joint Surg 64A: 481-488, 1982. Lonstein JE: Screening for spinal deformities in Minnesota schools. Clinical Orthopaedics and Related Research 126:33-42, 1977. Palmisani M, Bettini N, Gargiulo G, Nardi Y, Rizqualloh F, Cosco R, Savini R: The epidemiology of idiopathic scoliosis in the city of Bologna: A three year review of positive cases. Chir Organi Mov 75:353-360,1990. Rogala, EJ, Drummond DS, Gurr J: Scolosis: Incidence and natural history. J Bone Joint Surg 60A: 173-176, 1978. Smyrnis P, Valavanis I, Alexopoulos A, Siderakis G, Giannestras NI: School Screening for Scoliosis in Athens. J Bone Joint Surg 61B: 215,1979. Soucacos PN, Soucacos PK, Zacharis KC, Beris AE, Xenakis TA: School Screening for scoliosis: a prospective epidemiological study in northwestern and central Greece. J Bone Joint Surg 79A: 1498-1503,1997. Zhang GB, Li ZR, Wei XR, Li ZS, Cui QL: Application of Moire topography in school screening for scoliosis. J Chinese Surg 25:387-389,1987.

75

77;. fl. Gri\-as(Ed.i Research nun Spinal Deformities 4

School Screening in the heavily industrialized area Is there any role of industrial environmental factors in Idiopathic Scoliosis prevalence? TB Grivas, P Samelis, BD Polyzois, B Giourelis, D Polyzois Scoliosis Clinic, Orthopaedic Department, "Thriasio " General Hospital G. Genimata Avenue, Magula, 19600 Greece E-mail: [email protected] Abstract. Introduction: School-screening programs contributed greatly to the study of idiopathic scoliosis (IS) prevalence. A similar program confined to a highly industrialized area is being performed in our Department. Thus the comparison of the findings of IS prevalence of this program with those of programs performed in non-industrialized areas of the same country could imply the significance of special industrial environmental factors on IS aetiology. Materials and Methods: 3039 schoolchildren (1506 boys, 1533 girls), aged 5,5 to 17,5 years, have been screened for IS. These children comprise 20% of a total population of 20000 schoolchildren, who live in the region. The detection of the scoliotic children was attained utilizing the criterion of the angle of trunk inclination (ATI). The Prujis scoliometer was used to assess ATI. A cut off point of > 7° ATI was used as a criterion for children's referral to hospital. 262 (8,6%) were referred for further evaluation, whereas 118 (3,9%) among these children underwent radiological examination. Results: 90 children were found to have a Cobb angle of > 10° at their standing PA spinal radiographs (2,9 % of the screened population). A Cobb angle of 10° -20° was found in 74 (2,4%) children. Sixteen (0,5%) children, who had scoliotic curves with a Cobb angle of £20°, underwent conservative treatment by means of spinal orthosis. Relatively to their location on the vertebral column, 20% of the scoliotic curves were thoracic, 26,7% thoracolumbar, 20% lumbar, 24,4% double and 8,9% miscellaneous. Discussion: The screened area represents a place of particular interest because it experienced considerable environmental pollution during the past decades without any improvement of the available Health Services. A quite diverse population in relation to its occupation and its origin inhabits this area as well. The scoliosis incidence found in this area is similar to the incidence observed (2,9%) at other non-industrialized geographical departments of this country (2,6%). This implies that industrial environmental factors probably do not significantly influence the prevalence of AIS.

1. Materials and Methods From 17/1/1997 to 25/1/1999, during School screening for Scoliosis performed by the Orthopaedic Department of the Thriasio General Hospital of Elefsina in the region of Thriasio Pedio, 3039 children (1506 boys, 1533 girls), of ages between 5,5 to 17,5 years were examined. The total population of the pupils in the aforementioned area counts approximately 20000 children, which attend Elementary and High School.

T.B. Grivas et al. /School Screening in the Heavily Industrialized Area

77

This School-screening Program has been carefully organized, which enabled the examiners' team to rapidly obtain the maximal amount of possible information about the examined population. The Adam's Bending Test was performed in standing and sitting position and the amount of trunk rotation was assessed using the Pruijs scoliometer. The finding of Angle of Trunk Rotation (ATR) or Axial Trunk Inclination (ATI) of > 7° at any level of the lumbar, thoracolumbar or thoracic part during forward bending of the trunk, in a standing and sitting position, was used as a Pass-Fail criterion (or Cut Off Point) for the referral of the children for radiological examination [1,2]. Two hundred and sixty two pupils were referred to the hospital for further evaluation, 118 of which underwent radiological examination. This number represents 3,9 % of the examined population. Scoliosis was measured by the Cobb method [3]. 2. Results A summary of the successive steps in detecting and treating the scoliotic children after this school-screening program is presented in Table 1. One hundred and eighteen children underwent radiological examination of their whole vertebral column and chest (posteroanterior and profile standing radiograph). A Cobb Angle of > 10° was found in 90 children. This implies that the prevalence of scoliosis detected by school screening at Thriasio Pedio arises to 2,9 % of the examined population. The majority of the scoliotic children are girls, or 2 % of the examined pupils (boys: 0,9 %). The higher ratio of scoliotic girls is observed in all ranges of the Cobb angle, (table 2, figure 1). Furthermore, this ratio increases in the more serious cases. So the scoliotic girls-to-boys ratio turns from 2:1 at values of the Cobb angle of 10°-19°, to 14:1 when the Cobb angle is 20°- 40°. Depending on the location on the vertebral column the scoliotic curves are double curves (DB) 33.3%, lumbar curves (L) 20.0%, thoracic curves (T) 18.9%, thoracolumbar curves (TL) 27.8%. In scoliotic boys the left sided scoliotic curves predominate over the rightsided ones, regardless of the type of the curve, whereas in scoliotic girls a predominance of Right Thoracic and Left Lumbar curves was observed. Table 1: The steps in detecting and treating scoliotic children at Thriasio Pedio

Screened population

Children referred for further examination at Hospital (referrals)

Children who were finally examined at outpatients at Thriasio Gen. Hospital

Children referred for radiological examination

Scoliotic children followed up

Scoliotics treated with BOSTON BRACE

Girls

1533

170

115

77

48

15

Boys Girls/ Boys ratio Total

1506

92

63

41

26

1

1.01 3039 (100%)

1.84 262 (8,6%)

1.82 178 (5,8%)

1.87 118 (3,9%)

1.84 74 (2,4%)

15 16

(0,5%)

78

T.B. Grivas ct al. /School Screening in the Heavilv Industrialized Area

Figure 1: the ratio between scoliotic boys and girls

3. Discussion Thriasio Pedio is an area of particular interest. It is the main industrial area of Attica. It is inhabited by people who belong to a great variety of ethnic groups (native Greeks, Greeks who emigrated from the former Eastern Europe and the USSR, Gypsies, emigrants from Albania). They exercise various occupations (agricultural, industrial workers), and they are of a divergent range of educational status (analphabets, alumni of elementary school, high school and university) and of social classes. On the other hand, Thriasio Pedio is undoubtedly the most industrialized area of Greece: petrol refineries, metal industries, shipbuilding companies, chemical industries are the great majority of industries concentrated in this area, where approximately 300.000 industrial workers earn their daily living. High industrialization is accompanied by a proportional amount of environmental pollution, which was not followed by any improvement of the available Health Services. The referred pupils at Thriasio Pedio represent the 8,6 % of the examined population. This relatively high percentage of the referrals can be explained by the fact that in the beginning of the School screening a lower pass-fail criterion has been applied, namely ATR^6_. The purpose of the usage of the lower ATR was the attempt to select a group of children for clinical follow up and study of the natural history of their trunk asymmetry. On the other hand, the criterion of ATR>7° has been strictly followed in children who were examined by X-rays: only 118 (3,9 %) of the total of the examined pupils underwent radiological examination. This percentage is comparable to results published in other studies [4,5], which state that the ATR>7_ criterion leads to a referral ratio for radiological examination of about 3 % of the examined population. This criterion limits the false negative and false positive cases and thus lowers the total cost of School screening and the potential social discomfort to parents and children (psychological concern and absence from work or school) [4,6]. The incidence of AIS at Thriasio Pedio (2.9%) is comparable to the overall incidence (2,6%) of School screening - detected AIS in other geographic

T.R. Grivas et al. /School Screening in the Heavily Industrialized Area

79

departments in Greece [7]. It seems that the known environmental and social economic factors do not influence the incidence of AIS. Table 2: the number of the scoliotic children depending on the size of the Cobb angle COBB ANGLE 10_-19_ MALE

TYPE OF CURVE

DB L T TL

Scoliotic children

Count % within sex& Cobb angle

FEMALE

Left

Right

Left

Right

5 5 3 3 16

2 1 3 4 10

6 5 3 8 22

10 2 6 8 26

26 28,9

48 53,3

MALE Left

20_-40_ FEMALE

Right

Left

Right

1

2 3

1

1 6

5 1 2 1 9

1 1,1

15 16,7

Scoliotic children % Count within curve 30 33,3 18 20,0 17 18,9 25 27,8 90 100

The girls at Thriasio Pedio are more susceptible to develop scoliosis compared to boys. The same applies for Thessaloniki and loannina [8,9] but not for Kriti [10], where scoliosis affects equally both sexes. Several authors report a higher prevalence of AIS in girls [11,12,13,14], while other authors did not observe any difference [5,15,16]. After regular follow up of scoliotic children in Thriasio Pedio detected by school screening, Boston Brace was applied in 16 cases, of which the vast majority were girls (15 girls vs. 1 boy). Prevention of AIS focuses on early detection and on early initiation of treatment. It thereby aims to stop the vicious circle of the natural history of scoliosis and even to reverse it [5,17]. It is well known that scoliosis develops (worsens, resolves or remains) following the changes of the growing skeleton [4,18]. The early detection and the appropriate follow up of the population at risk to develop scoliosis [19] should be part of the available Public Health Services in order to protect the population from subsequent mental, physical and social complications attributed to severe scoliosis. 4. Conclusion The incidence of School screening detected AIS in Thriasio does not differ significantly to the overall incidence of AIS in Greece. This implies that industrial environmental factors probably do not influence the prevalence of AIS. This fact does not exclude the possibility that other than industrial environmental factors might be implicated in the development of AIS in this particular area, but more data are required to prove such a suggestion.

T. B. Grivas el al. / School Screening in the Heavily Industrialized Area

References 1. 2. 3. 4. 5. 6. 7. 8. 9.

10.

11. 12.

13. 14. 15. 16. 17. 18. 19.

Murrell GAC, Coonrad RW, Moorman CT, III, Fitch RD. An Assessment Of The Reliability Of The Scoliometer, Spine 1993:18(6) 709-712 Huang, S-C. Cut-off Point of the Scoliometer in School Scoliosis Screening Spinel997; 22: 1985-1989 Aunnell WP. The natural history of scoliosis. Clin Orthop 1988; 229:20-5. Bunnell WP. An objective criterion for scoliosis screening. J Bone Joint Surg [Am] 1984;66:1381-7. Lonstein JE, Bjorklund S, Wanninger MH, et al. Voluntary school screening for scoliosis in Minnesota. J Bone Joint Surg [Am] 1982; 64:481. Bunnell, WP. Outcome of Spinal Screening, Spine, 1993,18:(12), 1572-1580. Grivas TB, Koukos K, Koukou U, Theocharis N, Samelis P: 2001: Idiopathic Scoliosis - The analysis of the results of School screening in Greece. Abstract Book, Orthopaedics, 14, (2), 32 Kapetanos G: School screening in Macedonia: In: Grivas TB (ed): School screening for Scoliosis, Athens Paschalides Medical Publications, 2000, ISBN 960-7398-74-2, pp 48-53. Soultanis K, Zacharis K, Gelalis I, Soucacos PN: School screening in loannina. Identification and comparing study of Idiopathic Scoliosis in 4 geographical compartments in Greece. In: Grivas TB (ed): School screening for Scoliosis, Athens Paschalides Medical Publications, 2000, ISBN 960-7398-74-2, pp 26-33. Koukourakis I, Kouvidis I, Giannakoudakis N, Garefalakis N, Giaourakis G: School screening in Crete. In: Grivas TB (ed): School screening for Scoliosis, Athens Paschalides Medical Publications, 2000, ISBN 960-7398-74-2, pp 71-80. Chan A, Moller J, Vimbani G, Paterson D, Southwood R, Sutherland A: The Results of scoliosis screening in Australian adolescents. Med J Aust 145:379-383, 1986, Palmisani M, Bettini N, Gargiulo G, Nardi Y, Rizqualloh F, Cosco R, Savini R: The epidemiology of idiopathic scoliosis in the city of Bologna: A three year review of positive cases. ChirOrgani Mov 75:353-360, 1990., Weinstein, MD: Adolescent Idiopathic Scoliosis: Prevalence and Natural History: Instructional Course Lectures 1989, Volume 38:115, Soucacos NP, Soucacos K.P, Zacharis CK, Beris EA and Xenakis AT: School screening for scoliosis. J. Bone Joint Surg. 79A: 1498., 1997. Smyrnis PN, Valavanis J, Alexopoulos A, Siderakis G, Giannestras NJ: School screening for scoliosis in Athens. J Bone Joint Surg [Br] 61:215-217, 1979, Brooks HL, Azen SP, Gerberg E, Brooks R, Chan L: Scoliosis: A prospective epidemiological study. J Bone Joint Surg [Am] 57:968-972,1975. Ashworth, MA (ed.). Symposium on school screening for scoliosis. Scoliosis Research Society. Spine 1988; 13:1177. Dhar, S., Dangerfield, P. H., Dorgan, J. C., and Klenerman. Spinel993, 18:(1) 1419.Correlation Between Bone Age And Risser's Sign In Adolescent Idiopathic Scoliosis Soucacos PN, Zacharis K, Gelalis J, Soultanis K, Kalos N, Beris A, Xenakis T, Johnson EO. Assessment of curve progression in idiopathic scoliosis. Eur Spine J (1998) 7: 270-277

Th.B. Grivas (Ed.) Research into Spinal Deformities 4 IOS Press. 2002

Biomechanical factors affecting progression of structural scoliotic curves of the spine S. Lupparelli, E. Pola, L. Pitta, O. Mazza, V. De Santis, L. Aulisa Clin. Orthop. Pol. A. Gemelli - Universit_ Cattolica delSacro Cuore, Roma, ITALY Abstract: The development of the spine is affected by both biological and mechanical factors. As the geometry of the motion segment changes throughout growth, so does the mechanical behaviour of the spine owing to changing vectors acting on a variable geometry system. The biomechanical analysis of the growing spine enables the assessment of the role played by biological and mechanical factors in the pathogenesis of progressive scoliosis to be assessed and its comparison with factors acting on an adult scoliotic spine. The knowledge of these principles is instrumental to setting the right parameters for treatment and to design braces that may be capable of obtaining correction of the deformity. The elastic behaviour of child and adult spine differs because of both physiologic and pathologic conditions. In child scoliosis an abnormal geometry causes a persistent stress concentration in crucial areas of the motion segment. This induces a progressive elasto-plastic strain which modifies the geometry of the motion segment, thus worsening the stress concentration and the excessive strain through a vicious cycle. In adult scoliosis, on the other hand, deformation primarily affects the viscous-elastic structures, namely the intervertebral disc and the capsuloligamentous structures. This produces instabilty of the motion segments and slow deformation of the vertebrae through remodelling. It therefore ensues that the aim of the treatment differs in both conditions. In the child spine the aim is to prevent the motion segment deformity by means of braces which adequately modifies the stress distribution acting on the spine, thus enabling the spine to grow according to a quasi-physiological model. In adult scoliosis a stable equilibrium is required in order to prevent further deformation of the motion segment.

1.

Introduction

The evolutionary process of the skeletal deformities, and of the spine in particular, is conditioned by both biological factors and by the mechanical behaviour imposed by the new geometry of the system. The treatment of scoliosis and of hyperkyphosis follow such a principle. This resulted in the realisation of orthosis which, interfering with the natural dynamics of the spine, allowed, in the most successful cases, to get a substantial stabilization of the deformity. However, a less empirical biomechanical approach would specify the therapeutic choices and would design garrisons able to offer, when possible, a meaningful recovery of the deformity. The importance, therefore, of biomechanical studies aimed at defining the role played by the mechanical factors in the pathogenesis of the deformity is clear.

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S. Luppeirelli el cil. / Kiomechanical Factors Affecting Progression

2. Elastic behaviour of the spine In previous studies it has been observed that a spine in natural equilibrium is, in mechanical terms, an elastic carrying structure organized in many segments of movement; this structure is in a coercive state and so it is charged by bound energy [I]The entire spine, during the movements deriving from the natural dynamics, is subject to an elastic deformation. The spine structure has the capability of quickly returning to the primitive configuration when the actions that have produced the same deformation cease. The capability of returning, after every elastic deformation, to a ready and complete recovery of the natural state proves that the bound could be considered to have little importance in comparison to the elastic one. In this recovery of the natural state a physical phenomenon occurs, which, in the mechanical analysis of a system, takes the name of dynamic stability of a structure. The behaviour of an injured spine is different, since the loss of or the deterioration of some restriction bounds impose an unnatural mobility, followed by an altered elastic behaviour. In fact, while the intact column has a minimum bound energy, the injured spine, due to the incapacity to achieve a complete recovery of the natural state, has a progressively increasing bound energy. In the damaged spine a progressive increase of the elasto-plastic deformation will occur, at the elastic ones' expense, resulting in the generation of coercive states which are linked to some internal actions that progressively modify the geometric configuration of the whole structure. 3. Elastic behaviour of the scoliotic spine The scoliotic spine, because of the complex anatomical alterations that characterize it, changes in a meaningful way its own mechanical behaviour. In fact, the appearance of abnormal restraining reactions modifies the elastic properties of the system, favouring the accumulation of bound energy. Moreover, geometry's alteration induces a new model of the stress distribution, to which follows a concentration of tensions in specific areas of the vertebrae, of the disks and of the capsulo-legamentosus apparatus. The altered elastic behaviour and the concentration of the tensions induce coercive states and relative elasto-plastics deformations of the system. Such a mechanical behaviour can produce a permanent condition of unstable equilibrium. Therefore, the geometric configuration of the curve can progressively change, as time passes, due to mechanical factors. However, it is necessary to underline that the progression of a scoliotic curve is conditioned by the capacity of the biological structure to react to the induced forces and by the type of answer that the different structures offer to the same forces. According to such a principle, both the skeletal maturity level and the elastic characteristics of the restraining elements, moreover the characteristics of the intervertebral disks, take great importance. Age influences the different evolutive behaviour of the scoliotic curve, leading to the distinction between infanto-juvenile and adult scoliosis, based on clinical data. This concept is amply confirmed by the biomechanical analvsis.

S. Lupparelli et al. / Biomechanical Factors Affecting Progression

Infanto-juvenile scoliosis is characterized by the quick evolution, until the spine reaches the skeletal maturity. The plasticity of the bone tissue in growth mostly contributes to the worsening of the scoliotic curve. In the deformed spine, the action of the loads translates as concentrations of tensions in specific vertebral areas, and determines, due to the plastic reaction to the actions, typical of the growing bone, an asymmetrical development of the pedicles, of the vertebral soma and of the neural arch. The consequence is that, during growth, the scoliosis gets worse as the result of the progressive deformation of the vertebrae curve. Adult scoliosis, instead, are characterized by a slow development, so much that, for a long time, it has been considered not evolutive. Nowadays, the tendency to worsen recognizes, as principal cause, the instability of the movement segments included within the curve, if vertebral microfractures has been excluded. In the adulthood the instability shows as a progressive elasto-plastics deformation of the ligamentosus and diskal structures. It follows a deterioration of the restraining reactions with the formation of abnormal bounds. This modifies all the angular movements of the motion segments, in the three dimensions of the space. Instability is expressed by a progressive alteration of the geometric relationships between the single vertebrae, which determines subluxation phenomena in rotation and kyphosis of the movement segments included in the curve. As for the capacity of the biological structure to react to the induced loads, particular importance has the viscous-elastic ownership of the restraining elements. These, in fact, undergo many variations in relationship to both the age of the patient and the location of the deformity, and are able to condition, from a quantitative point of view, the phenomena expressed by mechanical factors. Such a behaviour can be studied by the biomechanical analysis of the G modulus of torsion rigidity of the intervertebral disks, that expresses, from a qualitative point of view, the resistance of the disks to the torsion determined by the action of a couple of forces. In previous studies it has been analysed, through a spine model, the course of the rigidities in relationship to the position of the disks in the spine and to the age of the person [2], [3] [4] (Fig. 1 and 2). In such a spine model, the G modulus presents, in the T2-T7 tract, elevated values and an homogeneous course. The high values, expression of a greater rigidity, that limits the torsion phenomena, and the homogeneous distribution, explain why the curves that include such disks are characterized by a harmonic evolution distributed through the motion segments included in the curve. In the lumbar spine, on the contrary, the values of the G modulus of torsion rigidity are inferior and are not homogeneously distributed, showing a significant reduction in skull-caudal direction. Therefore, the lumbar curves are characterized by a disharmonic evolution due to rotatory subluxation phenomena. Moreover, low G modulus of the lumbar disks, in association to the spine imbalance in the area with the most elevated loads, justifies the high degree of instability of the lumbar curves.

83

84

.S LitpfKirelli ct til. / Riomcchanutil Factors Affci

Fig.l Variation of the G modulus of elasticity of the disks in the adult model spine

Fig. 2 Variation of the G modulus of elasticity of the vertebral disks from T3 to L5 depending on age. The curves, shown as DT8....DT12 and DL1....DL5, rapresent the diagrams of the G values of the disks below respective vertebra.

S. Lupparelli et al. / Biomechanical Factors Affecting Progression

4. Conclusions In infanto-juvenile age the worsening of the scoliosis is the expression of a progressive deformation of the vertebrae, induced by an abnormal concentration of loads. The therapeutic act, therefore, must aim to reduce significantly such concentration and, where possible, to produce an inversion of the loads. In the presence of evolutive curves, therefore, the only valid therapeutic garrison is the brace, which, to be effective, must be used full time, until growth end [5] [6] [7]. In adulthood the most important factor of worsening is represented by the degree of instability, that varies in relationship to the location of the curve. The therapeutic approach to the adult scoliosis is based on the statement that is not possible to make a sure prognosis based exclusively on mechanical criteria. The reactions of the biological structure are able to influence the evolutive course of the scoliosis or, more rarely, to stop it, reaching a new equilibrium or forming new bounds, hi fact, during the structuring process of the curve, with the loss of some bound restriction, the biological structure is able to restructure itself creating new bounds, to guarantee a condition of stable equilibrium [8]. These are partly documentable and show by the hypertrophy of the articular apophyses, by the formation of osteophytes that determine a partial absorption of the loads and by the spontaneous arthrodesis of one or more segments. The therapeutic act of the adult scoliosis will be related to the degree of instability. In the minor instability the aim is to reduce the intensity of the loads and to optimise their distribution. This aim can be obtained with isometric exercises and with a correct educational posture. In the mild instabilities it can be useful the use of a brace in the period of restructuring of the curve. The treatment of the severe instabilities is, instead, surgical.

References 1.

Vinciguerra A, Aulisa L, Ceccarelli M. Stabilita e comportamento elastico del rachide. Minerva Orlop Traumatol 37: 717-723,1986

2.

Fineschi G, Aulisa L, Vinciguerra A. La rigidezza del rachide alia torsione. Progr Patol Vert 11:109-117,1990

3.

Aulisa L, Vinciguerra A, Tamburrelli F, Lupparelli S, Di Legge V. Biomechanical Analysis of the Elastic Behaviour of the Spine with Aging. In: Research into Spinal Deformities 1, J. A. SevastiK and K. M. Diab (Eds.) IOS Press: Amsterdam, 1997, pp. 229-231. Vinciguerra A, Di Benedetto A, Aulisa L. Sulla determinazione delle caratteristiche elastiche del rachide toracolombare. Minerva Ortop Traumatol 35: 133-138,1984 Aulisa L, Di Benedetto A, Vinciguerra A. Un'analisi biomeccanica del sistema tutore-rachide nelle scoliosi idiopatiche. Arch Putti 31: 185-194,1981 Aulisa L, Vinciguerra A, Valassina A, La Floresta P. II trattamento ortopedico mediante corsetto P.A.S.B. Progr Patol Vert 12: 135-142,1991

4. 5. 6. 7.

Fineschi G, Aulisa L, Vinciguerra A, Valassina A. Aspetti biomeccanici dei corsetti per il trattamento incruento della scoliosi. Minerva Ortop Traumatol 44: 543-548,1993

8.

Di Benedetto A, Vinciguerra A, Pennestr_ E, Aulisa L. Biomechanics of scoliosis using a new type of brace. In: Proceedings of the 8th Canadian Congress of Applied Mechanics, Moncton, N-B, Canada, June 7-12, pp 785-786,1981

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Tli.B. GrivasiEdi Rcseiirch into Spinal Deformities 4 I OS Press. 22

Positional cloning strategies for idiopathic scoliosis Stavros Bashiardes', Rose Veile', Carol A. Wise^, Laszlo Szappanos^, Michael Lovett* 1 Department of Genetics, Washington University School of-Iedicine, St. Louis, AIO, USA

2 Sarah Al. and Charles E. Scay' Center for Alusculoskeletal Research, Texas Scottish Rite, Hospital for Children, Dallas, TX, USA Abstract. >4rm: Idiopathic scoliosis (IS) affects approximately 1-2% of the population and has a heritable component. It is clear that in general IS displays the features of a complex genetic disorder; however families displaying a Mendelian inheritance pattern have been described. Our aim is to identify families segregating rare, highly penetrant loci. In the case described here the disorder appears to cosegregate with a chromosomal rearrangement. Methods and Materials: We have studied a family in which a pericentric inversion of chromosome 8 appears to cosegregate with idiopathic scoliosis in three generations. We have used fluorescent in situ hybridization (FISH) to identify cloned DNAs that span the breakpoints on the two arms of the chromosome. These clones allow the recovery of sequence information from the breakpoint region and identification of candidate genes. Results: We have identified a YAC of 1190kb that spans the p arm breakpoint and from this a cosmid of 35kb that also identifies the break. We have derived DNA sequence information on this region. We have identified a BAG of 150kb that crosses the q arm breakpoint. The complete genomic DNA sequence of this BAC is being analyzed to identify candidate genes and to further localize the precise breakpoint. Conclusion: We have sublocalized within two small genomic regions the position of a possible locus for idiopathic scoliosis.

The familial nature of idiopathic scoliosis (IS) has been widely described [1,2] and many epidemeological studies have suggested that approximately one third of IS cases may be familial [3] Even though a strong genetic component for IS is generally accepted, the mode of inheritance is unclear and the available studies sometimes support conflicting theories. The overall risk of scoliosis exponentially declines as one progreses from first to second to third degree relatives. This is consistent with a multi-factorial mode of inheritance [4]. At present, the genetic components that underly multi-factorial disorders can be identified by four distinct routes. Genetic linkage/association studies on large family collections or collections of sporadic cases, coupled with positional cloning methods are routes that hold great promise. However, this type of approach is severely complicated by the fact that IS appears to be both heterogeneous in its' genetic causes and also frequent in occurrence. Gene expression profiling methods, such as gene chips or Serial Analysis of Gene Expression (SAGE) are also very powerful methods for the identification of potential key players (and genetic loci) in disease states [5]. Unfortunately, this type of analysis is difficult to apply to IS because it is unclear what tissue(s) to profile and which exact comparisons should be made. Another successful route into the genetic underpinnings of

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87

complex disease is to ideunfy families that exhibit early onset disease and that appear to segregate highly penetrant alleles. We recently applied this approach in the successful cloning of a gene that causes a severe immunoinflammatory disease [6]. The final approach is to identify a chromosomal alteration that results in the disease state cloning [7, 8]. Balanced chromosomal rearrangements that cosegregate with disease have proved extremely useful in the identification of the molecular basis of many Mendelian traits. Type 1 neurofibromatosis [9, 10], poly cystic kidney disease [11], Duchenne muscular dystrophy [12] and Lowes syndrome [13] are just a few examples of diseases that have benefited from this approach. Chasing chromosomal breakpoints as markers for the location of susceptibility genes is open to the criticism that the correlation may be coincidental. In this context it is relevant to point out that a large epidemiologi cal study of early developmental disorders [14] concluded that about two thirds of observed chromosomal abnormalities were probably causally related to these early onset disorders. When later onset disorders are considered (such as IS) this number may be much higher.

Figure 1: Family with scoliosis in three generations used in our study. Father and son (X-ravs indicated) have a common chromosomal rearrangement identified as a pen centric inversion of Chromosome 8.

Therefore, as a parallel approach to our ongoing positional cloning strategies, we sought to identify a balanced chromosomal rearrangement in at least one familial IS pedigree. One small family we have studied, with scoliosis in three generations, appears to cosegregate with a pericentric inversion of chromosome 8. The G-banded metaphase of one affected member is shown in Figure 1. Our strategy to identify the precise breakpoint involved using genomic information to walk to and clone the chromosomal break regions and identify flanking genes.

Figure 2: G-banded Metaphase of father. Wildtype Chromosome 8 and Chromosome 8 wiLh pericentrie inversion are shown bv arrows.

8S

5. Bashiardes el ai / Positional Cloning Strategies for Idiopathic Scolio.iix

Fluorescence In Situ Hybridization (HSH) was used to identify YAC and BAG clones that spanned the breaks on the p-arm and q-arm of chromosome 8. These clones were used to walk to those regions, identifying ones that lie above, below and across the breaks. The position these BACs and YACs map to on the chromosome with respect to the breakpoints were classified according to the location that fluorescence was observed on the chromosome during the FISH experiments (Figure 3). The actual results observed during our HSH experiments are illustrated in Figure 4. In this case, we are illustrating results with respect to the q-arm of the chromosome, the same principle was applied to clone the p-arm break point. The BACs and YACs that were characterized as crossing the breakpoints

Figure 3: Schematic representation of results expected during FISH experiments. All representations of expected FISH results are shown for q-arm. (A) indicates the pericentric inversion occuring (B) Position of BAC hybridization and consequently fluorescence of a BAC that maps below break point. (C) Position of Fluorescence for a BAC that maps above break point. (D) Position of fluorescence for a BAC that crosses the break point

were subdoned into cosmids and those that crossed the breaks were identified by FISH. Sequence information from these cosmid clones and comparison with the completed human genome sequence was used to determine the presence of disrupted genes in the region. This analysis revealed that the p-arm does not appear to break any known gene whereas in the q-arm we have identified a gene that is disrupted by the break

Figure 4: Results obtained during FISH experiments. (A). BAC that maps below break on q-arm. (B) BAC that maps above break on q-arm. (C) BAC that crosses break point on q-arm.

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occurring during the pericentric inversion. Currently, we are analyzing sporadic IS patients for mutations in the identified genes using predicted exon sequences.

References 1. 2. 3. 4. 5. 6.

7.

8. 9.

10. 12.

13.

14.

Beals, K. K. Nosologic and genetic aspects of scoliosis. Clinical Orthopaedics 93 (1973) 23-32 Hairington, P.R. The etiology of idiopathic scoliosis. Clinical Orthopaedics 126 (1977)17-25 Weinstein, S. L. Advances in the diagnosis and management of adolescent idiopathic scoliosis Journal of Pediatric Orthopaedics 11(1991) 561-3 Riseborough, B. J., Wynne Davies, K. A. Genetic survey of idiopathic ScoliosiS in Boston, Massachusetts. Journal of Bone and Joint Surgery 55-A (1973) 974-982 Blackshaw, S., Fraioli, K. E., Furukawa, T., Cepko, C. L. Comprehensive analysis of photoreceptor gene expression and the identification of candidate retinal disease genes. Cell 107 (2001) 579-589 Wise, C. A., Gillum, J. D., Seidman, C. E., Lindor, N.M., Veile, K., Bashiardes, S., Lovett. M. Mutations in CD2BP- disrupt binding to RYP PEST and are responsible for PAPA syndrome an autoinflammatory disorder. Human Molecular Genetics 11 (2002) 961-969 Bugge, M., Bruun-Petersen, G., Brondum-Nielsen, K., Friedrich, U., Hansen, J., Jensen, G., Jensen, P. K. A., Kristoffersson, U., Lundsteen, C., Neibuhr, E., Rasmussen, K. R., Rasmussen, K., Tommerup, N. Journal of Medical Genetics 37 (2000) 858-865 Collins, F. S. Positional cloning moves from perditional to traditional. Nature Genetics 9 (1995) 347-350 Fountain, J. W., Wallace, M. K., Bruce, M. A., Seizinger, B. R., Menon, A. G., Gusella, J. F., Michels, V. V., Schmidt, M. A., Dewald, G. W., Collins, F. S. Physical mapping of a translocation breakpoint in neurofibromatosis. Science 244(1989)1085-1087 The European Polycystic Kidney Disease Consortium. The polycystic kidney disease I gene encodes a ~4kb transcript and lies within a duplicated region on chromosome 16. Cell 77(1994) 881-894 Ray, P. N., Belf~l, B., DuIT, C., Logan, C., Kean, V., Thompson, M. W., Sylvester, J. E., Gorsky, J. L., Schmickel, K. D., Worton, R. G. Cloning of the breakpoint of an X:21 translocation associated with Duchenne muscular dystrophy. Nature 318 (1985) 672-675 Attree, 0., Olivos, I. M., Okabe, I., Bailey, L. C., Nelson, D. L., Lewis, K. A., Mclnnes, K. K., Nussbaum, K. L. The Lowels oculocerebrorenal syndrome gene encodes a protein highly homologous to inositol polyphosphate~5~phosphatase. Namre. 358 (1992) 239-42 Warburton D. DC novo balanced chromosome rearrangements and extra marker chromosomes identified at prenatal diagnosis: clinical significance and distribution of breakpoints. American Journal of Human Genetics 49 (1991) 995-1013

Research into Spinal Deformities 4 IOS Press. 2002

Prediction of Curve Progression in Idiopathic Scoliosis from Gene Polymorphic Analysis Masatoshi Inoue, Shohei Minami, Yoshinori Nakata, Masashi Takaso, Yoshinori Otsuka, Hiroshi Kitahara, Keijiro Isobe, Toshiaki Kotani, Tetsuro Manila, Hideshige Moriya. Department of Orthopedic Surgery, School of Medicine, Chiba University, 1-8-J Inohana, Chuo-ku, Chiba, Japan.

Abstract. Three hundred and four girls with adolescent idiopathic scoliosis were investigated to determine if DNA polymorphisms in the vitamin D receptor (VDR), estrogen receptor (BR), and CYP17 gene were related to curve progression of idiopathic scoliosis. The results suggested that XbaJ site polymorphism in the ER gene was associated with curve progression. The Cobb's curve angle with genotype XX and Xx was statistically greater than that with genotype xx. The curve progression risk (~5 degrees) was higher for genotype XX and Xx than for genotype xx. Furthermore, patients with genotype XX and Xx had a higher risk of receiving operative treatment than those with genotype xx. In conclusion, DNA analysis may predict curve progression, although other polymorphisms were not associated with curve severity.

1.

Introduction

Many research studies have been performed to identify factors that predict curve progression in idiopathic scoliosis. Twin studies revealed that curve progression was related to a hereditary factor [1,2], while other studies indicated that it was influenced by skeletal and sexual maturation [3, 4, 5]. Currently, growth and sexual maturation in girls are considered to be influenced by hereditary factors. Techniques of DNA analysis have revealed that nucleotide sequence variation in the human genome is common. These single base pair differences in DNA nucleotide sequence are inherited in Mendelian codominant manner. If a DNA sequence difference occurs within a restriction enzyme recognition sequence, the restriction enzyme fragments produced will be different lengths in different people, producing restriction fragment iengdi polymorphisms (RFLPs). Several investigators recently ascertained that RFLPs of several genes were responsible for menarcheal age as well as increase in height. Genes associated with growth in height include the vitamin D receptor (VDR), estrogen receptor (ER), and dopamine receptor (DRD2) [6, 7, 8, 9], while genes associated with menarcheal age include VDR and CYP17 [10, 11].

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Since in scoiiosis, curve progression is influenced by growth and puberty, we hypothesized that some variant of these genotypes might be related to curve progression in idiopathic scoiiosis. The purpose of this study was to investigate the relationship between DNA polymorphisms found in the VDR, ER, and CYP17 gene and the severity of idiopathic scoiiosis

2. Patients and Methods Patients with idiopathic scoiiosis were evaluated by clinical examinations and roentgenograms. The curves were measured by Cobb's method, and girls with a curve greater than 10 degrees with rotation were included. All patients were followed until growth maturation, and the maximum Cobb's angle during follow-up was selected for analysis. In addition, curve progression was defined as progression greater than 5 degrees from the initial evaluation. Exactly, 304 girls with adolescent idiopathic scoiiosis, who gave informed consent to DNA analysi- could be followed until the time of growth maturation. The mean (L SD) initial Cobb's angle was 24.6 ±10.0 degrees, and the mean (±SD) maximum Cobb's angle during follow-up was 31.3± 12.6 degrees. The mean menarcheal age was 12.3±1.2 years, and the mean age at growth maturation was 15.0±1.6 years. The mean (±SD) height was 158.3±5.6 cm, while the mean arm span was 161.6±6.4cm. The indication for brace treatment was a curve magnitude greater than 25 degrees with a Risser grade of 3 or less, and that for surgery was a curve magnitude greater than 45 degrees. In sum, 42,109, and 153 patients received operations, brace treatment, and did not undergo curve progression or refused brace treatment, respectively. As for the curve pattern, if minor curves were 10 degrees or more, a curve pattern was defined as a double curve. In sum, 189, 62, 25, 13, and 15 patients had double curves, a right thoracic curve, a thoracolumbar curve, a lumbar curve, and triple curves, respectively. Patient lymphocyte DNA samples were extracted from peripheral blood. The restriction fragment length polymorphisms (RFLPs), which included the VDR Apal, Fokl, and the TaqI site polymorphism, the ER PvuII and the XbaJ site polymorphisms, and the CYP17 MSPAI site polymorphism, were selected for analysis. All RFLPs were first amplified using the polymerase chain reaction (PCR) as described previously [6,7,11, 12], and then subsequently digested with each restriction enzyme, with the genotypes determined by gel electrophoresis. The RFLPs were coded as Pp (PvII) and Xx (Xbal), where the uppercase letter indicates the absence of the site, and the lowercase letter indicates its presence. Association between each genotype and the maximum Cobb's angle, and association between each genotype and idiopathic scoiiosis treatment were compared using the x^ test or the one-way analysis of variance (ANOVA) as appropriate. P value differences of 0.05 were considered statistically significant.

M. Inoue et al. /Prediction of Curve Progression in Idiopalhic Scoliosis

3. Results Table 1 shows the VDR, ER, and CYP17 genotype distribution. The frequency ofApal, Fokl, and TaqI site polymorphisms for the VDR genotypes and MspAl for the CYP17 genotype in idiopathic scoliosis patients was not significantly different from controls previously described [6, 7, 11]. As for the ER genotype distribution, the PvuII site polymorphism frequency was not significantly different from controls previously described. However, the genotype XX frequency for the Xbal site (Group A) was 14%, which was greater than the 3% frequency reported by other groups [12, 13,14]. As for the ER gene, the Xbal site polymorphism was associated with curve severity. The mean (± SD) Cobb's angle with genotype XX and Xx was greater than that with genotype xx, with statistically significant differences (Table 2). The ER PvuII site polymorphism was unrelated to curve severity. Furthermore, other polymorphisms in the VDR and CYP17 genes were not associated with curve severity (Table 2). Table 1. Genotye distribution in each group Gene RFLP Group A VDR Apal 0.10 VDR Fokl 0.46 VDR TaqI 0.80 ER PvuII 0.21 ER Xbal 0.14 CYP17 MspAl 0.27

Group B 0.47 0.46 0.18 0.47 0.25 0.55

Group C 0.43 0.08 0.02 0.32 0.61 0.18

Group A: restriction site absence in both alleles, such as XX or PP Group B: heterozygous, such as Xx or Pp Group C: restriction site in both alleles, such as xx or pp

Table 2. RFLPs and curve severity association Cobb's angle (degree) Group B Gene RFLP Group A 31.9±15.8 31.3±12.1 VDR Apal 30.5±11.9 31.6±12.8 VDR Fokl 31.0±12.7 VDR Taql 31.5±11.9 ER PvuII 33.6±14.6 31.1±12.3 34.2±13.7 34.9±15.8 ER Xbal 30.2±12.4 31.2±12.7 CTP\7MspAI Data are mean ±SD. N. S.: not significant (P>0.05). Group A: restriction site absence in both alleles, such as XX or PP Group B: heterozygous, such as Xx or Pp Group C: restriction site in both alleles. such as xx or pp

P value Group C 30.5±12.1 32.2±15.1 30.6±15.7 30.1±11.7 29.3±11.0 29.8±12.5

(ANOVA) N. S. N.S. N.S. N.S. 0.002 N.S.

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Table 3. RFLPs and curve severity association (The brace treatment patients were excluded) Cobb's angle (degree) P value Group B Group C Gene RFLP Group A 30.6±19.7 27.6±16.3 31.4±26.3 VDR Apal 27.8±17.9 34.0±24.5 30.2±18.8 VDR Foki 29.0±22.5 30.9±22.5 29.1±18.3 VDR TaqI 30.1±17.6 34.2±21.7 25.6±15.3* ER PvuII 36.3±18.7 35.3±21.8 24.5±14.8 ER Xbal 30.0±19.5 27.2±18.0 27.6±16.9 CYPllMspAl

(ANOVA) N. S. N. S. N. S. N. S. 0.05). *P30 degrees was 55%, 57%, and 42% for patients with genotype XX, Xx, and xx, respectively (P = 0.04). Additionally, the risk of Cobb's angle >40 degrees was 29%, 26%, and 12% for patients with genotype XX, Xx, and xx, respectively (P = 0.004) (Table 5). Table 4. Association between ER Xbal site RFLP and curve progression Genotype Curve progression XX Xx XX 34 (44%) 5 degrees

16(38%)

43 (56%)

71(38%)

Analysis was by x^ test. "Curve progression" was defined as progression greater than 5 degrees.

M4

M. Inoiie et til. /Prediction of Curve Progression in Idiopathic Scoliosi\

Table 5. Association between Xbal site RFLP and the risk of Cobb's angle >30 and > 40 degrees Genotype Cobb's angle XX Xx XX P value 19(45%) 33 (43%) 108 (58%) 30 degrees 23 (55%) 44 (57%) 77 (42%)

Cobb's angle 40 degrees Analysis was by x^ test.

12(29%)

Table 6. Association between the ER Xbal site RFLP and scoliosis treatment Genotype XX Xx XX Treatment 33 (79%) 58 (75%) 171 (92%) Non-op (45 degrees) Op: operation Analysis was by x^ test.

P value ineni(il Kincnmtic Trunk Morion

pressure maps COP patterns and opto-electronic 3D kinematic measurements enlightening the contribution at several body levels with a particular focus on the spine.

2. Methods In order to proceed to the joint kinematic and COP patterns analysis, we use both optoelectronic measurement system and force platforms or baropodographic systems. In the protocol adopted we measure the 3-D spatial positions of 27 small passive markers placed on anatomical repere points located on the patient's head, spine, trunk and lower limbs. The vertebral column is identified by 11 markers placed on the spinous processes from C7 down to S3 every second vertebra, while the head, chest and pelvis movements are taken into account by placing markers on the zygomatic bones, chin, sternum, ASIS and PSIS respectively [3,4]. The three dimensional co-ordinates of the markers are measured with an accuracy of 1mm at lOOHz sampling rate by using an optoelectronic posture analyser equipped with two pairs of TV cameras filming the patient's back and front. Vertical ground reaction forces and centre of pressure (C.O.P.) time courses are simultaneously recorded. COP analysis is approached by using bivariate scattergrams statistical techniques. To ensure uniformity with COP pattern analysis, only horizontal plane projections of spatial coordinates are taken into account to extract bivariate scattergrams for kinematic variables. In this case, the correct statistical model is the "correlation statistical model" in which it is generally sought to determine whether two variables are independent or covary. A number of parameters are in general used in descriptive statistics to quantitatively identify scattergrams behaviour and characteristics. A full discussion of such statistics is beyond the aim of this paper, in which only the most important parameters are summarised; the reader can refer to [5] for a complete treatment. The main quantitative parameters used are the so called two principal axes of motion, the equal-frequency ellipses and confidence ellipses. The first ellipse refers to statistical behaviour of the actual sample while the second one refers to statistical characteristics of the bivariate expected mean. The bivariate mean per each variable (and the related standard deviation) are firstly assessed identifying the centre position of the ellipses. The variance-covariance matrix is then determined and its eigenvalues are used both to assess the directions of ellipses major and minor axes and to estimate the level of variability of the considered variables along the latter. The shape of such ellipses is a function of correlation between variables, and the area of the ellipse is a function of confidence coefficient 1 - a. "Equal-frequency" ellipses describe the covariation found in a sample. They enclose about 100(1 - a)% of the observations in the given sample. On the other hand "confidence" ellipses for the bivariate mean are expected to contain the true parametric mean at a 100(1 - a)% probability.

3. Results To illustrate the procedure outcomes, two kinds of postural trials on a 30 years old healthy subject are taken into account: a 10 seconds indifferent orthostasis and a right lateral spinal bending (starting from an indifferent orthostatic standing position untill to maximum lateral flexion). Analysis of orthostatic averaged posture enlightened the subject presented on the frontal plane a slight scoliotic lateral deviation with right convexity at lumbar level, and a slight compensation with left convexity at upper level. Moreover, the subject presented a lateral right global offset. On the sagittal plane, the subject showed the hyper-kyphosis at thoracic level, a forward position of the pelvis and finally a forward global offset. By analysing the directions of the estimated main axes of motion and the dimension of 95%

M. D 'Ainico ami P. Roncoletta / Joint Seff mental Kinematic Trunk Motion

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equal-frequency ellipses, particularly at spine metameric level (C7 to S3 every second vertebra), compared to force platform COP motion, it is evident how the oscillation of the spine is higher and in different direction with respect to the COP, thus confirming lhat COP analysis alone cannot represent adequately the complexity of motor control applied by CNS to maintain upright stance. This last aspect is proved also in the analysis of the lateral bending test, where the directions of the estimated main axes of motion and the dimension of equalfrequency ellipses of spine landmarks, indicate some «locked and/or push-pull phase» oscillating regions along with movement execution. The COP motion is of course smaller in size in that COP is constrained not to move out of the global feet area support in order to avoid the fall.

Fig. 1 Orthostatic Posture Average Standing Skeleton Model frontal and sagittal view (left panel). Posturographic analysis -95% equal frequency ellipses- of spine (behaviour starting from C7 to S3 every second vertebra) and Force platform COP pattern (last bottom-right box).

Fig. 2 Lateral Bending Skeleton Model frontal and sagittal view (left panel). Posturographic analysis of spine (behaviour from C7 to S3 every second vertebra) and Force platform COP pattern (last bottom-right box).

Conversely, the size of COP motion in relationship with that of other body districts can witness the good quality of CNS control in maintaining balance. Such possibility to subdivide segmental spine and body mobility into congruent movement regions give important insights about CNS motor control actions and balancing adopted strategies, correlating them with individual anthropometrical morphological characteristics.

M. D'Amico ami P. Koncolctui /Joint Scxmcnidl Kinematic Trunk Minion

Fig. 3 Lateral Bending. Posturographic analysis -95% equal frequency ellipses- of spine (behaviour starting from C7 to S3 every second vertebra) and computed angular variations of main ellipses axis directions along each evaluated level

3. Conclusions The presented methodology allows to point out different CNS motor control strategies and provides a powerful tool to better characterise pathological influences enlightening particular segmental behaviour at various body levels. In this sense, it demonstrates to be particularly useful for the study of pathological conditions that can alter static and dynamic balance.

References 1. 2. 3.

4. 5.

F.B. Horak et al., Components of Postural Control in the Elderly: A Review, Neurobiology of Aging, 10:727-738, 1989. D. Winter, Human Balance and Posture Control during Standing and Walking, Gait & Posture 3 (I99S) 193-214. D'Amico M. et al., 3D Spine Morphology Identification by Mean of Parametric Curve Modelling and Self-Adapted Digital Filtering, Proceedings of the 8th Int. IMEKO Conf. on Measurement in Clinical Medicine, Dubrovnik, 16-19 September 1998,1998,8/26-8/31. M. D'Amico et al., A 3-D Parametric BJomechanicaJ Skeleton Model for Posture and Spine Shape Analysis, Proceedings of the 3rd IRSSD Meeting, Clermont-Ferrand France (2000), in press. R. Sokal and J. Rohlf, Biometry The Principles and Practice of Statistics in Biological Research, W.H. Freeman and Company, New York, 1994

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Transverse Plane Pelvic Rotation Measurement Brennen Lucas, Marc Asher, Terrence Mclff, Dick Lark, Doug Burton Kansas University Medical Center, Kansas City, Kansas USA Abstract: Aim: To determine how pelvic rotation in the transverse plane relates to coronal plane anatomical landmark location. The problem this addresses is the observation that iliac crest medial lateral width as seen in the coronal plane Cobb is often asymmetrical in patients with idiopathic scoliosis before treatment, and sometimes after treatment. Materials and Methods: A pelvis was marked with radiographically opaque markers at symmetrical sites in the ilium, sacrum and acetabulum; mounted in a jig; and radiographed at varying degrees of transverse and sagittal plane angulation. The medial lateral distance from two similar landmarks on opposite sides of the pelvis was then determined and a left/right ratio correlated with the degrees of transverse plane angulation. In addition, a theoretically derived equation was developed to describe the effect of pelvic shape on the degree of transverse plane rotation. Results: The left/right ratio for the distance from the sacro iliac joint to the anterior superior iliac spine proved to be the most reliable for determining the degree of pelvic rotation in the transverse plane. The relationship is nearly linear up to 2S( rotation and is little influenced by the degree of sagittal plane angulation. Based on theoretical considerations, the importance of the anterior to posterior angular relationship of the two coronal plane landmarks measured influences the degree of rotation but not the linear relationship. Conclusion: Within limits the transverse plane rotation of the pelvis can be determined by a left/right ratio of the distances between two similar landmarks on each side of the pelvis.

1. Aim

For many years we have pursued the concept of idiopathic scoliosis correction as being torsional and countertorsional loads in the transverse plane.1'2 We have reported some success in accomplishing this correction.3'4 In the process we have noted that torsional loads sometimes appear to be translated to the pelvis with postoperative pelvic rotation in the direction of the applied thoracolumbar/lumbar torsion. We have also observed that this transmitted torsion usually appears to lessen or resolve with time. This study addresses how to determine the relationship between pelvic rotation in the transverse plane and anatomical landmark location as seen in the coronal plane. 2. Methods & Materials This study was based on the hypothesis that bony landmarks in the pelvis visible in the coronal plane could be determined that would reflect transverse plane rotation. This follows Nash and Moe's experiments on vertebral body transverse plane rotation.5 A pelvis was marked with radiographically opaque markers at symmetrical sites on the ilium at the inferior edge of the sacroiliac joint (I), the lateral most projection of the anterior superior iliac spine (ASIS), the outer superior lateral edge of the acetabulum (A),

154

H. Lucas et a/. / Tn/n\\t'r\c Plane Pclvu. Rotation Measurement

the projected center of the femoral heads (FH), the medial and lateral edges of the obturator foramen (MO and LO), as well as the base of the spinous process at SI (MID). It was mounted in a positioning jig and radiographed posterior to anterior at a tube film distance of 183 cm (72") in varying degrees of transverse, sagittal, and coronal plane angulation. The medial to lateral distances on radiographs from two similar landmarks on opposite sides of the pelvis were measured, and a left/right ratio was calculated and correlated with the degrees of transverse plane angulation. In addition, a lateral x-ray of the specimen was obtained, and two theoretically derived equations were developed to describe the effect of pelvic shape and the location of compared landmarks on the degree of transverse plane rotation. The effect of any intrinsic differences in right to left hemipelvis sides was not studied. 3. Results The left/right ratio for the distances on radiographs from the inferior ilium adjacent to the sacroiliac joint to the anterior superior iliac spine (I-ASIS) proved to be the most reliable for determining the amount of pelvic rotation in the transverse plane. The relationship was nearly linear up to 25° transverse plane rotation and was little influenced by the degree of sagittal or coronal plane angulation or by the vertical location of the x-ray beam, either aimed at the thoracolumbar junction or directly at the pelvis. Based on theoretical considerations, the importance of the anterior to posterior projected transverse plane angular relationship of the two coronal plane landmarks measured influenced the linear relationship of the left-right hemipelvis ratio, the corresponding degrees of transverse plane pelvic rotation, and the linear relationship of the left-right ratio to the transverse plane rotation. For the adult female pelvis model studied, left-right I to ASIS ratios of .5 and .75 approximated 10° and 5° of clockwise transverse plane pelvic rotation and ratios of 2 and 1.3 approximated 10° and 5° of counterclockwise rotation, respectively.

4. Conclusion Within limits the transverse plane rotation of the pelvis can be determined by left-right ratios from the distance between two similar landmarks on each side of a symmetrical pelvis. The most reliable distances we found were the horizontal distance between vertical lines drawn through the inferior edge of the ilium at the sacroiliac joint and the lateral most shadow of the anterior superior iliac spine. To convert the ratios to degrees requires additional, more complex calculations. 5. Acknowledgments The authors wish to thank Terry Orrick, academic secretary, and Barbara Funk, editor, for their assistance in the preparation of this manuscript. This study was supported in part by the Marc A. and Elinor J. Asher Research Endowment at the Kansas University Endowment Association and the Scoliosis Research Fund, Kansas University Surgical Association.

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6. Conflict of interest disclosure See Asher et al: Trunk deformity correction stability... This volume.

References 1. 2. 3. 4.

5.

Asher, M.A.: Isola spinal instrumentation system for scoliosis. In The Textbook of Spinal Surgery. Edited by Bridwell, K.H., and Dewald, R.L. Philadelphia, Lippincott, pp. 569-609, 1997. Asher, M.A., and Burton, D.C.: A concept of idiopathic scoliosis deformities as imperfect torsion(s). Clin.Orthop. 364:11-25,1999. Burton, D.C.; Asher, M.A.; and Lai, S.M.: The selection of fusion levels using torsional correction techniques in the surgical treatment of idiopathic scoliosis. Spine 24:1728-1739, 1999. Gondo, H., and Asher, M.A.: Mid-term effects of Isola instrumentation on the configuration of the spine and the thoracic cage in adolescent idiopathic scoliosis. In Research into Spinal Deformities. Edited by Sevastk, J.A. and Diab, K.M. Amsterdam, IOS Press, pp. 433-436,1997. Nash CL Jr., Moe JH. A study of vertebral rotation. J Bone Joint Surg 51A:223-229,1969.

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Tli.R.Gri\-(i.\tE

4. Discussion and Conclusion The burden of such complex processing is justified by the peculiarity of the obtained results. In fact, in this way, the true mean gait cycle phase can be correctly identified. By the analysis of its time courses variations and of all the possible derived parameters, the foot/floor interaction investigation can rely on a statistical significance that improves the clinical and biomechanical reliability and understanding of the obtained results. The proposed method allows to obtain a mean gait cycle phase each frame of which is obtained as a complex, mathematically rigorous averaging process. We propose this approach to increase the statistically significance of foot/floor interaction analysis.

Fig. 4. Mean Stride pressure maps and vertical forces assessed from the above locomotion. (See text)

M. D 'Ainico and P. Roncolelta / Baropodographic Measurements and A veragin}>

\ 61

References 1.

2. 3. 4.

5. 6.

7. 8.

P. Dangerfield et al., Gait Analysis ogf Patients with Adolescent Idiopathic Scoliosis, Three Dimensional Analysis of Spinal Deformity (Eds. M. D'Amico et al.) Proceedings Of the 2nd Int Sym. On 3D Scoliotic Deformities, Pescara 1994, IOS Press, 1995,297-301. R. Sokal and J. Rohlf, Biometry The Principles and Practice of Statistics in Biological Research, W.H. Freeman and Company, New York, 1994 M. Whittle, Gait Analysis An Introduction, Butterworth-Heinemann, Oxford, 1996. M. D'Amico and G. Ferrigno, Technique for the Evaluation of Derivatives from Noisy Biomechanical Displacement Data Using a Model-Based Bandwidth-Selection Procedure, Med. & Biol. Eng. & Comput 28, pp. 407-415 (1990). M. D'Amico and G. Ferrigno, Comparison between the More Recent Techniques for Smoothing and Derivative Assessment in Biomechanics, Med. & Biol. Eng. & Comput 30, pp. 193-204 (1992). M. D'Amico and P. Roncoletta, A Self-Adapted Filtering Procedure for Normalisation and Averaging, IFMBE Proceedings of the 9th Mediterranean Conference on Medical and Biological Engineering and Computing, Pula Croatia (2001), pp.6-41 - 6-44. M. D'Amico et al., A 3-D Parametric Biomechanical Skeleton Model for Posture and Spine Shape Analysis, Proceedings of the 3rd IRSSD Meeting, Clermont-Ferrand France (2000), in press. M. D'Amico, Algorithm for Estimation, Classification and Graphical Representation of Clinical Parameters in the Measurement of Scoliosis and Spinal Deformities by Means of Non-Ionising Device, in Three Dimensional Analysis of Spinal Deformity (Eds. M. D'Amico et al.) Proc. Of the 2nd Int Sym. On 3D Scoliotic Deformities Pescara Sep. 94, IOS Press 1995,33-38.

Movement analysis of scoliotic subjects using Fastrak Aziz Rahmatalla ', Nachiappan Chockalingam 2'3, Peter Dangerfield 3, El-Nasri Ahmed ', Tom Cochrane2, John Dove ' and Nicola Maffulli l ' Hartshill Orthopaedic Centre, North Staffordshire Hospital, Stoke on Trent ST46QG 2 School of Health, Staffordshire University, Leek Road, Stoke on Trent ST4 2DF 3 Departments of Clinical Anatomy and Cell Biology and Musculo Skeletal Medicine, University of Liverpool, Liverpool L69 3GE

Abstract. An attempt has been made to simplify the measurement of composite movement involving abnormal rotation in scoliosis, which is considered to have an important role in the diagnosis and treatment of the condition. Analysis of three-dimensional movement provides pertinent information concerning the morphological description of scoliotic deformities. The description of this movement is of clinical interest for aiding diagnosis and/or prognosis of spinal deformity evolution. Previous studies have indicated that idiopathic scoliosis is a three-dimensional deformity accompanied by a generalised torsion phenomenon and attempts have been made to associate the geometric torsion index with the curvi-linear shape of idiopathic scoliosis. Although previous investigations have documented the three-dimensional reconstruction of scoliotic spine, most methods either expose the subject to a high level of radiation, as in stereo-radiographs, or demand a high degree of technical input and time, as in video based gait analysis systems. This study employs an electro magnetic field capturing system (FASTRAK) to estimate the spinal movements. This simple system is inexpensive and highly portable. Furthermore, it can give instant graphic and numerical values of the composite movement. The results of this study indicate the usefulness this system in the diagnosis of scoliosis and highlights the possibility of its uses in screening school children and other surveys.

1. Introduction Although previous studies have successfully demonstrated 3D reconstruction of the spine from radiographs [1], there remains a need to evolve a non-invasive measurement that would describe the configuration of the scoliotic curve in three dimensions. A number of non-invasive measurements have been reported including the use of Scoliometer (I SI Instruments) [2], formulator [3], electrogoniometer [4] and other electromagnetic techniques [5]. Some of these measurements have been criticised for their poor precision and inadequate diagnostic accuracy [2]. While most studies focussed primarily on the resultant back surface shape and rib hump geometry, Pearcy [5] demonstrated the efficient use of electromagnetic techniques to obtain accurate and reliable results for trunk measurements. Smidt [6] reported a potentiometer system to study range of movement and spine configuration. While indicating that the thoraco-lumbar ranges of motion for scoliotics and normals were similar, this study observed similar effects for normals and scoliotics in a variety of seated positions.

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Previous investigations have examined the coupling motion in the thoracic spine and demonstrated a repeatable upper thoracic movement pattern within and between subjects [7]. Commercially available non-invasive electromagnetic systems measure the position and orientation of a skin mounted sensor (receiver) relative to a fixed source (transmitter) in space. These systems demonstrate high resolution, good accuracy and repeatability. However, as in other skin marker based systems, accuracy is affected by the skin movement artefacts [5]. 2. Methods The Fastrak electromagnetic tracking system (Polhemus Navigation; Colchester, VT, USA), which has been described elsewhere, [8] was used for this study. 9 patients (3 males and 6 females) with a mean age of 15 years (range 12-20) participated in the study. Data was collected from four receivers attached to the skin by strips of double sided adhesive tape over the spinal processes of C7, T6, T12 and SI. The patient was asked to perform three cycles of maximum flexion/extension, right and left side lateral bending and right and left rotational movement at their own pace. . The study received approval by the local Ethics Committee.

3. Results

left axial rotation

right axial rotation

Time Figure 1: Graphical display of the movement at C7, T6, T12 and SI at the dominant planes

Figure 1 indicates results from a typical trial. The first three cycles represents movement during flexion and extension. The second shows the movement of the right and left lateral flexion. The last three cycles represent the right and left axial rotation. All measurements started from the zero position and the actual angles at the start point were recorded. The pattern of movement and the associated symmetry between the right and left sides between and across subjects as well as the ratio between the dominant and minor movement in different planes were investigated. Figure 2 shows the comparison between dominant and coupling movement at various joints and the table 1 shows the range of motion at various levels.

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c7 flex/ext

c7 lat bending c7 rotation T6 flex/ext

T6 lat bending T6 rotation Tl2 flex/ext

Tl 2 lat bending \ Tl2 rotation si flex/ext

si lat bend Figure 2: 3-D display of dominant and couplings movemen

si rotation

Table 1: Mean values in degrees of spinal movement of 9 cases C7

T6

T12

SI

Flexion

109.27

109.77

80.49

49.21

Extension

27.01

23.56

14.95

11.83

Right bending

50.85

40.07

20.65

10.34

Left bending

47.89

41.50

19.48

12.15

Right rotation

94.65

73.03

64.62

63.04

Left rotation

87.59

75.63

57.11

55.07

Figure 3

Figure 4

•

A. Rahmatalla et al. /Movement Analvsix of Scoliotic Subjects using Fastrak

Figure 5

Figure 7

165

Figure 6

Figure 8

Figures 3 to 8 show the graphical representation of various movements ie flexion, extension, right lateral bending, left lateral bending, right axial rotation and left axial rotation respectively at different levels of the spine. Figures 9 and 10 shows the composite movement during lateral flexion at T6 and T12 respectively.

4. Discussion

Figure 9

Figure 10

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Spinal deformity is characterised by 3-D changes in the spinal column. Therefore any correction of such a deformity requires accurate assessment of any changes to the normal spinal curvatures such as lordosis and kyphosis, or detecting abnormal structural changes such as rotation. Existing methods either allow 2-D static analysis or expose the patients to a high level of radiation [5]. Video and camera tracking systems provide threedimensional analysis but these techniques are expensive, time consuming and require high technical skill to operate. With the introduction of electromagnetic tracking systems, movement analysis, with a capability of computing with 6 degrees of freedom (3 translational and 3 angular orientations in real time), is now possible. These systems have been used in other fields such as animation, navigation, and virtual reality applications. The results of the present study have demonstrated good reproducibility over number of cycles. The investigation has examined the pattern of movements and the relationship between the dominant plane and coupling movement. Preliminary results indicate that there is excessive rotational coupling, and to a lesser degree, flexion during right and left lateral bending at T6 and T12. There are no reciprocal movements during rotation and this may prove to be significant in clinical conditions. Although previous studies have compared Fastrak and a similar potentiometer based (CA6000: Spine Motion Analyser) system and demonstrated a good test-retest reliability, no conclusive evidence is reported on the accuracy of measurement of true angular movements of the vertebrae [9]. Frontal plane angles were comparable between both systems but the sagittal and transverse plane angles were significantly different. However, Mannion and Troke (1999) compared only lumbar segment range of movement and the values could be different for thoracic region, which is not, reported anywhere. The Fastrak system, reported in this study, may provide the solution to the need for inexpensive, simple and portable tools which can be used for surveying technique outside hospital and clinics. The system also has a high degree of accuracy and good inter- and intra- reliability and reproducibility [8,9]. References 2

M. J. Pearcy and S. B. Tibrewal, Axial Rotation and Lateral Bending in the Normal Lumbar spine measured by three-dimensional radiography. Spine 9(6) (1984) 582-587. 3 P. Cote, B. G. Kreitz, J. D. Cassidy, A. K. Dzus, J.A. Martel, Study of the diagnostic accuracy and reliability of the scoliometer and Adam's forward bend test. Spine 23 (1998)796-803. 4 P. H. Dangerfield, J. S. Denton, S. B. Barnes, N. B. Drake, The assessment of rib cage and spinal deformity in scoliosis. In I A F Stokes et. al., eds. Surface topography and spinal deformity: Gustav Fischer Verlag, Germany. 1987, pp. 53-66. 5 W. S. Man-as, M. Pamianpour, J Y Kim, S. A. Ferguson, R. R. Crowell, S. R. Simon, The effect of task asymmetry, age and gender on dynamic trunk motion characteristics during repetitive trunk flexion and extension in a large normal population. IEEE transactions on Rehab. Eng. 2 (1994) 137 - 146. 6 M. J. Pearcy, R J. Hindle, New method for the non-invasive three dimensional measurement of human back movement Clinical Biomechanics 4 (1989)73-79. 7 G. L. Smidt, S. E. VanMeter, M. D. Hartman, S. E. Messaros, D. L. Rubsam, K. A. Welle, Spine configuration and range of motion in normals and scoliotics. Clinical Biomechanics 9 (1994)303-309. 8 D. Theodoridis and S. Riston, The effect of shoulder movements on thoracic spine 3D motion. Clinical Biomechanics 17 (2002) 418-421. 9 K. Jordan, K. Dziedzig, P.W. Jones, B.N. Ong, P.T. Dawes,. The reliability of the three-dimensional FASTRAK measurement system in measuring cervical spine and shoulder range of motion in healthy subjects. Rheumatology 39 (2000) 382-388. 10 A. Mannion and M. Troke, A comparison of two motion analysis devices used n the measurement of lumbar spinal mobility. Clinical Biomechanics 14 (1999)612-619.

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Motion segment stiffness measured without physiological levels of axial compressive preload underestimates the in vivo values in all six degrees of freedom Mark G. Gardner - Morse, Ian A. Stokes , David Churchill, Gary Badger Department of Orthopaedics and Rehabilitation, University of Vermont, Stafford Hall, Burlington, Vermont 05405-0084, USA Abstract: Axial preload is known to alter the mechanical properties of spinal motion segments. The objective of this study was to compare the experimentally measured loaddisplacement behavior (stiffness, hysteresis and linearity) of porcine lumbar motion segments in vitro with physiological axial compressive preloads of 0, 200 and 400 N equilibrated in a physiological fluid environment. At each preload, displacements in each of six degrees of freedom (±0.3 mm AP and lateral translations, ±0.2 mm axial translation, ±1° lateral bending and ±0.8° flexion/extension and torsional rotations) were imposed. The resulting forces and moments were recorded. Tests were repeated after removal of posterior elements. Using least squares, the forces at the vertebral body center were related to the displacements by a symmetric 6x6 stiffness matrix. The stiffness, hysteresis area and linearity of six diagonal and two off-diagonal load-displacement relationships were examined for differences between preload conditions. Results: Mean values of the diagonal terms of the stiffness matrix for intact porcine motion segments increased significantly by an average factor of 2.2 and 2.9 with 200 and 400 N axial compression respectively (pO.OOl). Increases for isolated disc specimens averaged 4.6 and 6.9 times with 200 and 400 N preload (p2, Aziz Rahmatalla3, Peter Dangerfield2, Tom Cochrane ', ElNasri Ahmed 3 and John Dove 1

School of Health, Staffordshire University, Leek Road, Stoke on Trent ST4 2DF Departments of Clinical Anatomy and Cell Biology and Musculo Skeletal Medicine, University of Liverpool, Liverpool L69 3 GE 3 Hartshill Orthopaedic Centre, North Staffordshire Hospital, Stoke on Trent ST4 6QG 2

Abstract. Although various factors have been attributed to the etiology of idiopathic scoliosis, studies have indicated that the kinematic differences in the spine, pelvis and lower limb may contribute to the causation and progression of idiopathic scoliosis. The aim of this investigation was to identify asymmetries in lower limb kinematics and pelvic and back movements during level walking in scoliotic subjects that can be related to the spinal deformity. The study has employed a movement analysis system to estimate various joint angles in the lower extremities and other kinematic parameters in the pelvis and back. The results of a pilot study have highlighted the potential usefulness of a range of parameters in the indication of asymmetries and their implications for spinal deformity generation. While demonstrating the value that movement analysis systems may have in investigating pathogenesis and aetiology, these preliminary findings indicate that the identified variables can also used in the kinematic analysis of spinal deformities such as scoliosis. Further studies are being undertaken to validate these findings.

1 Introduction Detailed biomechanical description of normal and pathological gait is now possible with the help of gait analysis. Furthermore, gait analysis has now become a useful clinical tool providing an accurate three-dimensional measurement of gait [1]. Gait Analysis combined with optoelectronic systems would be useful, since it has a minimal interference in the walking pattern of a person [2]. Previous studies have investigated the factors responsible for the progression of normal gait [3] and the characteristics of pathological gait [4]. A number of studies have demonstrated the value of gait analysis in understanding the etiology of idiopathic scoliosis [5]. Scoliosis affects the physical orientation of the shoulders and head to the pelvis and lower extremities. Although previous investigations indicate the asymmetric growth of the vertebrae as a factor responsible for scoliosis [6,7,8] and the existence of a relationship between lateral flexion and axial rotation [9], the interaction between vertebral deviation and axial rotation is not fully understood [10]. Studies indicate that the causation and progression of idiopathic scoliosis is still unclear [11,12]. However, a recent extensive review indicates possible aetiological factors [13]. Furthermore, several reports suggest a lack of understanding in the pathomechanics of scoliosis progression deters the scientific treatment process [14].

I 74

,V. Clu>ck(ilini>am cr ai / Kinematic Differences in Lower Limb Chut AnJ*A Scjp bead II--^x "~--....

3

Results and discussion

Various gait cycle parameters are given in table 1 and mean kinematic measurements for various subjects during individual gait cycle are given in tables 2 and 3. These values indicate the maximum range of motion in a particular plane for a specified joint. Recorded gait cycle parameters do not show substantial asymmetries between left and right sides, except for the unloading response in 4 subjects. However there are intersubjects differences which can be attributed to the anthropometric measurements, cadence and gait velocity. Table 2 indicates inter-subject changes in pelvic tilt, obliquity and rotation. Examining the pattern of curves within subjects, indicates a minimal change in tilt and obliquity between the left and right side of the body. However, the internal and external rotation of the pelvis varies within and between subjects. There are pattern differences between the left and right side and the range of movement varies from 4 to 10 degrees. Although further studies are being conducted to validate the findings, these initial results support the theory put forward by Burwell et al., [21]. Table 3 indicates the results of the measurements at the hip. As shown for the pelvis, and taking anthropometric parameters into consideration, there is no substantial difference in the sagittal (Flexion/ extension) plane across and within subjects. However, there are differences in the frontal (adduction/ abduction) and the coronal plane angles (rotation) within and across the subjects. While demonstrating the usefulness of gait analysis in assessing spinal deformities in general and scoliosis in particular, the initial results of this study validate the Nottingham concept of pathogenesis of idiopathic scoliosis. Most published results, including the present study, concentrate on kinematic measurements. However, it would be useful to couple the movement data with force platform data as this would allow insight into the understanding of the relationship between movement patterns and the etiology of scoliosis.

References: 1. 2. 3. 4.

Chockalingam N, Dangerfield P H and Giakas G (2002) Biomechanical clinical assessment: an introduction to gait analysis, British Journal of Therapy and Rehabilitation, 9 (1), pp 15-23. Winter D A (1990), Biomechanics and motor control of human movement, Wiley - Interscience. Rose J and Gamble J G (1994) Human Walking, Willams and Wilkins. Gage, J. R and Koop, S. E (1995) Clinical gait analysis : Application to management of cerebral palsy. In Three Dimensional Analysis of Human Movement. Allard, P., Stokes, I. A. F and Blanchi, J. P (ed.). Human Kinetics, pp. 349-362.

176

5. 6. 7. 8. 9. 10. 11. 12. 13. 14 15. 16. 17. 18. 19. 20. 21. 22. 23 24. 25.

,V. Chockalini>(iii\ i'l al. / Kinematic Diffcrcin-cs

in Li>wci Linih (iitir Annl\'

Swatzky B, Tredwell S, Sanderson D (1997), Postural control and trunk imbalance following CotrelDubousset instrumentation for adolescent idiopathic scoliosis. Gait and Posture 5, pp 116 -119. Roaf R (1963) The treatment of progressive scoliosis by unilateral growth arrest . J. Bone and Joint Surgery 45 B: pp 637-651. Stokes I A F, Dansereau J, Moreland M S (1989). Rib cage asymmetry in idiopathic scoliosis. J Orthop. Res. 7: pp599-606. Tadano S, Sakai K, Kanayama M, Ukai T, Kaneda K (1994). Finite element simulation in the progression of idiopathic scoliosis. Second World Congress of Biomechanics. Veldhuizen A G, Scholten P J M (1987). Kinematics of the scoliotic spine as related to the normal spine. Spine 12: pp852-858. Stokes I A F, Gardner-Morse M (1991). Analysis of the interaction between vertebral lateral deviation and axial rotation in scoliosis. J Biomechanics 24: pp753-759. Sevastik J A (1987). Idiopathic Scoliosis. What is it ? In: Research into spinal deformities, ed by Sevastik J A, Diab K M. IOS Press. pp37-40. Stokes I A F (1997) Analysis of symmetry of vertebral body loading consequent of lateral spinal curvature. Spine 22: pp2495-2503. Burwell R G, Dangerfield P H, Lowe T G , Margulies J Y (2000). Etiology of Adolescent Idiopathic Scoliosis. State of the art reviews. Hanley & Belfus Inc.,USA. Burwell R G, Dangerfield P H (2000). Adolescent Idiopathic Scoliosis: Hypotheses of causation. In: Etiology of adolescent idiopathic scoliosis. State of the Art Reviews. Ed by Burwell R G, Dangerfield PH, Thomas G L, Margulies J Y, pp319-334. Crosbie J, Vachalathiti R, Smith R (1997). Patterns of spinal motion during walking. Gait & Posture, 5, pp6-12. Stokes V P, Andersson C, Forssberg H (1989). Rotational and translational movement features of the pelvis and thorax during adult human locomotion. JBiomechanics, 22, No (1) pp 43-50. Crosbie J, Vachalathiti R (1997). Synchrony of pelvic and hip joint motion during walking. Gait and Posture 6: pp237-248. Crosbie J, Vachalathi R, Smith R (1997). Age, gender and speed effects on spinal kinematics during walking. Gait and Posture 5: pp 13-20. Crosbie J, Vachalathiti R, Smith R (1997) Patterns of Spinal motion during walking. Gait and Posture 5:pp6-12. Vaughan C L, Davis B L, O'Connor J C (1999). Dynamics of Human Gait, Human Kinetics. Burwell R G, Cole A A, Cook T A, Grivas T B, Kiel A W, Moulton A, Thirlwall A S, Upadhyay S S, Webb J K, Wemyss-Holden S A, Whitwell D J, Wojcik A S, Wythers D J (1992). Pathogenesis of Idiopathic scoliosis: the Nottingham concept, Acta Orthopaedica Belgica, Vol 58, Suppl. 1, pp 33 - 58. Lemmers L G, Sanders M M, Cool J C, Grootenboer H J (1991). The cause of axial rotation of the scoliotic spine. Clinical Biomechanics 6: pp!79 -184. Beck R J, Andriacchi T P, Kuo K, Fermier R W, Galante J O (1981). Changes in the gait patterns of growing children. J Bone Joint Surgery 63 A: pp!452-1457. Elftman, Herbert (1939). The function of the arms in walking. Human Biology 11: pp529-535. Eke-Okoro S T, Gregoric M, Larsson L E (1997). Alterations in gait resulting from delibrate changes of arm swing amplitude and phase. Clinical Biomechanics 12: pp516 -521.

N. Chockalinffcim et al. / Kinematic Differences in Lower Limb Gait Analysis

111

Table 1 : Gait Cycle parameters Subject Loading Single Response Stance Right leg 10.41 1 39.58

Unloading Swing response

Step Cadence Stride Step Stride Duration Duration Length Length 0.48

104.16

1.37

0.57

0.13

1.43

0.5 0.48

96.15 100

1.18 1.16

0.55 0.61

0.1

1.14

0.06

1.16

0.98 1.04

0.5

102.04

1.19

0.58

0.11

1.21 1.14

10.41

39.58

40.38

11.53

36.53

0.96 1.04

3

11.53 14

38

10

38

1

4

10.2

38.77

14.28

2

Step Gait Width Veloi

5

11.53

34.61

17.3

36.73 36.53

0.56

96.15

1.18

0.56

0.07

6

14.06

35.93

14.06

35.93

1.28

0.64

78.12

1.23

0.62

0.09

1.07

7

15.38

34.61

13.46

36.53

1.04

0.52

96.15

0.98

0.52

0.17

0.94

0.48 0.54

104.16

1.28

0.58

0.07

1.34

94.33

1.23

0.68

0.02

1.16

1.42

0.54

0.09

1.4

1.26

0.55

0.09

1.26

Left leg

1

10.41

39.58

8.33

41.66

0.96

2

11.32

37.73

11.32

39.62

1.06

3 4

13.72

13.72

37.25 38

1.02 1

0.52

12

35.29 40

0.48

98.03 100

5 6

12 14.06

40 35.93

12

1

14.06

36 35.93

1.28

0.48 0.64

100 78.12

1.18 1.18

0.54 0.61

0.06 0.06

7

16.66

35.18

14.81

33.33

1.08

0.52

92.59

1.05

0.51

0.07

10

Table 2: Mean Kinematic measurements (Pelvis) Subject

Pelvic Tilt

1

7.8 10.26 4

2 3 4 5 6 7

3.55 4.26 3.07 6.7

Pelvic Obliquity 8.5 8.9

14.54 10.94

Pelvic Rotation 10 8.36 9.91 6.6

5.45

8.18

6.18 5.03

4.88 9.67

Table 3: Mean Kinematic measurements ( Hip) Right Subject

Left

Flexion/ Extension 43 46.26

Adduction/A bduction 11.69 16

Rotation

3 4

41.02

20.9

45.73

5

38.99

6 7

45.1

1 2

41.57

Flexion/ Extension 40.9 47.7

Adduction/A bduction 11.2 15.2

21.7

41.81

20.33

7.53

18.2 11.72

11.18 32.6 15.71

43.76 34.57

15.13 9.25

29.99 11.9

11.4 12.7

15.09 14.14

44.99 38.32

8.18 12.2

9.08 7.39

23.4 24.53

Rotation

22

1.18 0.92 0.97

Th.B GnvitstEiLi Research into Spinal l)c(f>nninc\ 4 I OS Pi < sv 22

Assessing Changes in Three Dimensional Scoliotic Deformities with Difference Maps D.L. Hill, D.C. Berg, T. Church, V.J. Raso Capital Health Authority, Glenrose Rehabilitation Hospital Site, Edmonton, AB Canada dhill@cha. ab. ca Abstract: Topographical difference maps were used to compare the trunk surfaces of subjects over the course of their treatment. Three-dimensional points representing the trunk surfaces were aligned accounting for growth and positioning. A goodness-of-fit score was calculated and a color map used to display trunk surface changes. Fifty-one successive subjects were assessed with difference maps. Two subjects each had 10 repetitions taken on the same day to assess reliability. A blinded observer used a five-point scale that extended from full agreement to full disagrment to judge the maps according to the extent and location of changes. The observations were compared to clinical measures mapped onto the same scale by another blinded observer. Goodness of fit for repeated measures averaged 5+1, for subjects deemed to have no change 7+2, for subjects with slight change 9+2, and 14+2 for subjects with significant change. Judges were in full agreement or in agreemnt with forty of the fifty-one subjects (78%) and in slight disagreement with the remaining eleven. When the cohort was subdivided in surgical, brace and no treatment groups, the judges were in full agreement or in agreement 76%, 80%, and 85% respectively. The difference map provides a qualitative and quantitative measure of how the trunk surface has changed as a whole.

1. Introduction The cosmetic deformity is an important concern to many adolescents with idiopathic scoliosis and often motivates them to seek treatment. Physical measurements consider asymmetries due to lateral sway, trunk rotation, abnormal sagittal profile, as well as waist, shoulder and scapula asymmetries [1]. Change in the deformity, not its absolute measure, provides the important information necessary for making treatment decisions. The physical measurements of the surface deformity do not always adequately describe the changes in deformity over time. Difference mapping provides a holistic technique for examining change in data sets. Early difference mapping in the medical field involved analyzing the shape of pregnant women's abdomens using moire" topograms [2,3]. Qualitative shape analysis has been used to assess the trunk and to compare changes during treatment [4]. More recent work includes the analysis of corneal shape [5] and dentition wear [6,7] using close-range photogrammetry. Elevation deviations are typically displayed as a 3D color-coded difference map to reveal abnormalities. In each of these examples, the surfaces are either compared to an idealized mathematical model, or fitted to previous surfaces with prominent surface features. These surface fitting algorithms are based on minimizing the least squares differences between the surfaces [8]. This works best for fitting surfaces with common landmarks, analytic models or surfaces with steep

D.L Hill et al. /Assessing Changes in Three Dimensional Scoliotic Deformities

179

gradients, as matching can be performed in areas of identical shape, leaving areas of change to be identified [2,3,8]. Unfortunately, the trunk surface lacks prominent features and does not lend itself well to this approach. Taking a full 360 degree view of the torso [10] may improve the surface matching by providing common landmarks and steeper gradients. The surfaces must be fitted manually as it is difficult to reliably and accurately choose landmarks, fit the back surface to an analytic model, or ensure that steep gradients exist from visit to visit. Surface matching is further complicated by the changing shape of the whole trunk through growth and/or weight change, unrelated to the effects due to the scoliotic deformities. 2. Objective The aim of this study was to assess the utility of difference mapping in the clinical followup of children with scoliosis. 3.

Materials and Methods

3.1 Generating the Difference Map Three dimensional trunk surface data sets were captured with a non-contact laser scanner [12]. The subject was positioned in a fixed frame to enhance reproducibility by maintaining predefined scanner-subject separation, and minimizing subject sway and whole body rotation. The subject took a deep breath, and asked to hold it for the 0.6 seconds required to capture the surface map. The surface map comprised up to 40,000 X,Y,Z coordinate points, measured in millimeters, and a TIF image to aid in visualization and image cropping. Difference maps were generated with a program written in MATLAB. The program accepted two ASCII coordinate files, and plotted them as a cloud-of-points in a window that allowed removal of extraneous points. These cropped surfaces were transferred to a surfacefitting window to align the surfaces. The first surface was fixed, while the second surface was manually manipulated to match the first as a best fit. Manipulations included translation in X, Y, and Z to account for differences in positioning, independent scaling in X and Y to account for growth and weight change, and rotation in pitch to account for possible forward leaning. Once the surfaces were matched to the operator's satisfaction, each surface was rendered onto a common triangular grid using standard MATLAB commands. The surfaces were then cropped to the original silhouette to minimize edge effects generated by interpolating the cloud-of-points to a regular grid surface. Areas within the region of interest, not containing surface data (i.e. outside the trunk boundary), were assigned a constant depth value on both surfaces to generate a controlled, common background. Both surfaces were interpolated to a grid of identical dimensions. To generate a difference map, the first surface was directly subtracted from the second on a point-by-point basis. This subtraction produced a third surface with Z values indicating the difference in depth between the original surfaces. Absolute depth differences of greater than 40mm were clipped to either + 40mm, to ensure a fixed depth gradient. A color map ranging from Red (+40mm) to Beige (Omm) to Blue (-40mm) matching the fixed depth gradient, was applied to the surface. A goodness-of-fit score was calculated, based on the average of the absolute value for all trunk surface points, with zero being a perfect match.

ISO

/) L. Hill ct ul. /,-Vv.u'.v.v/;;(,' Chtiniti", in Three Dimensional Scoliniii Dctormitii's

To establish a baseline for the goodness-of-fit score, two subjects each had ten surface images taken at the same session. The subjects moved freely between scans, and repositioned in the frame for each surface image. Each subject's ten topographies had two selected as the first surface against which the other nine were compared. The resulting 36 comparisons (two subjects X two selected references X nine comparisons) were the basis of the repeated measures calculation. The goodness-of-fit scores were only due to positioning and manual errors in fitting the surface images. 3.2 Evaluating the Difference Map Fifty-one consecutive subjects who had two surface topographic images were included. The visits were separated by a mean interval of 6 ± 2 months. The subjects (54 females, 7 males) had a mean age of 14 ± 2 years on their first visit. Of the fifty-one subjects, thirty-four (67%) were diagnosed with AIS and seventeen (33%) with scoliosis of a congential nature or secondary to other conditions. The study group was further divided by treatment modality into twenty-nine surgical subjects (both pre- and post-operative), eleven brace subjects, and eleven subjects undergoing observation only. Two observers judged the changes in surface topography, one observer used only the difference maps and the other observer used all the clinical information available, in the absence of the difference maps. Each subject's color-coded difference map (Figure 1) was generated and analyzed by a blinded observer knowledgeable in scoliosis. This observer was given no information about the subjects, only the 3D surface coordinate points. This observer scored each analysis into one of five categories (Much Better, A Little Better, No Change, A Little Worse, Much Worse). The observer also commented on how the surface topography had changed and recorded the goodness-of-fit score. To analyze the goodness-of-fit scores, A Little Better and A Little Worse were grouped together as slight change, and Much Better and Much Worse were grouped together as severe change. A second independent observer, blinded to the first observer's scorings, analyzed the clinical records for the visits used to generate the difference maps. Examining all available clinical measurements and impressions from the corresponding visits, the second observer scored the subject onto the same five-category scale. This observer also commented on how the individual had changed according to the established clinical measures (Cobb angle, trunk rotation, cosmetic score, scoliometer, and sagittal profile) and physician comments.

Figure 1. Difference map of a subject with moderate worsening of the deformity, showing increased kyphosis and trunk rotation in the thoracic region. Goodness-of-fit = 10.1

D.L Hill et id. /Assessing Changes in Three Dimensional Scoliotic Deformities

18 1

The two observers' category scores and comments were compared and further categorized into one of four levels of agreement. Subjects with identical category scores were considered in Full Agreement. Subjects whose category scores differed by one, but had a consistent deformity assessment were considered in Agreement. Those subjects with category scores differing by one, with inconsistent deformity assessment, were considered in Disagreement. Subjects whose category scores differed by more than one were considered in Full Disagreement. Consistency of the deformity assessment was based on comments on how the surface topography had changed, deemed to be consistent only when the observers agreed upon which specific features had changed (i.e. trunk rotation, flattening of the back, shoulder asymmetry). Agreement scores were analyzed for the entire group, as well as by treatment modality and clinical diagnosis. Goodness of fit scores were assessed using an unpaired two-tailed Student's t-test with a p=0.05 significance level. The effects of treatment and diagnosis were assessed using a chisquared test with Yates correction for discrete data at a p=0.05 significance level. 4.

Results

Judge 1 rated 26 subjects as no change, 21 with slight change, and 4 with severe change. Judge 2 rated 30 subjects as no change, 17 with slight change, and 4 with severe change. Goodness-of-fit scores averaged 5±1 for repeated measures, 7±2 for subjects deemed by judge 1 to have no change, 9±2 for subjects with slight change, and 14+2 for subjects with significant change. These groups were significantly different from each other at p5°, R> threshold and R had the same sign as LA. In other cases TST result was "Negative". Pose averaged LA and R angles are compared with the threshold for TST in functional poses. Only those arches location of which corresponded to that in a natural pose or differed in one or two vertebrae were included for averaging. Results of this comparison are presented in Tables 3 and 4. The analysis of sensitivity, specificity and positive predictive value of TST in functional poses demonstrated essential growth of the diagnostic efficiency, which is reflected in Table 4. Thus, the TST in functional poses is significantly better than the TST only in natural pose.

V..V. S(irnt«lski\' ct al. / Vsc of Functional Tests to Increase

Efficient^

Table 3. The findings for topographic screening test with group GO and G1 Result

Positive Negative Totals

TST only in natural posture Meanings of used thresholds for rotation R>1.5° R>2.0° R>2.5° R>3.0° GO Gl GO Gl GO Gl GO Gl 55 81 30 80 23 77 15 73 41 7 3 66 4 73 81 11 84 96 84 96 84 96 84 96

TST with functional poses Meanings of used thresholds for rotation R>2.5° R>1.5° R>2.0° R>3.0° GO Gl GO Gl GO Gl GO Gl 13 82 7 81 21 83 3 77 83 2 89 3 93 7 75 1 84 84 96 84 96 84 96 96

Table 4. Sensitivity, specificity and positive predictive value for topographic screening test TST only in natural posture | Meanings of used thresholds for rotation Sensitivity

Specificity PPV

TST with functional poses Meanings of used thresholds for rotation

R>1.5°

R>2.0°

R>2.5°

R>3.0°

R>1.5°

R>2.0°

R>2.5°

R>3.0°

96% 43% 60%

95% 69% 73%

92% 76% 77%

87% 84% 83%

99% 78% 80%

98% 86% 86%

96% 93% 92%

92% 97% 96%

5. Conclusion The performed studies demonstrated that use of functional poses allows solving the problem of high percentage of false-positive results of TST. It should be noted that due to complete automation of topographic data processing by COMOT method labour consumption of screening does not increase essentially. References Fomichev N.G., Kharinov V.N., Sarnadskiy V.N., Sadovoy M.A., Malakhov O.A. School spinal deformity screening by computer optical topography. Research into Spinal Deformities 2,1.A.F. Stokes Ed.), IOS Press, 1999, p.241. Drerup B., Hierholzer E. Back shape measurement using video rasterstereography and three-dimensional reconstruction of spinal shape, Clin. Biomech. 1994, Vol.9, pp. 28-36. Wojcik A.S., Phillips G.F., Mehta M.H. Recording of the back surface and spinal shape by the Quantec imaging system- a new technique the scoliosis clinic.J.Bone Joint Surg.,1994,V76-B(Supp. I), pp. 10-11.

777.fi. Grivas(E(l.) Research into Spinal Deformities 4 IOS Press. 2002

Cotrel-Dubousset instrumentation (GDI) in the treatment of congenital spinal deformities. Computer topography evalution Mikhailovsky M.V., Sarnadsky V.N., Khanaev A.L. Research Institute ofTraumatology and Orthopaedics, Department of Spinal Surgery for Children and Adolescents, 630091,Frunze str. 17, Novosibirsk, RUSSIA Abstract. Aim of the study. GDI and other types of segmental instrumentation are wide used in surgical treatment of congenital spinal deformities. At the same time we didn't find in orthopaedic literature any data concerning 3-D evaluation of the results of such procedures. The aim of this study is the assessment of 3-D effect of GDI using of computer optical topography.

1. Introduction Cotrel-Dubousset instrumentation (GDI), developed in 1983, is widely applied in the surgery of congenital deformations of the spine. Its high efficiency is convincingly proved by numerous researches (Dubousset,1985; Bradford, 1985; Winter,1988; Lonstein, 1991). In the last years methods of three-dimensional estimation of dorsal trunk surfaces of the patient for comparison of intervention results are used. For this purpose ISIS optoelectronic topographical system (Turner-Smith, 1993) based on computer and television techniques, and such systems as Formetic (Drerup, 1994) and Quantec (Wojcik, 1994) based on rasterostereography are most widely applied. In 1994 at Novosibirsk Research Institute of Traumatology and Orthopaedics a COMputer Optical Topography technique was developed based on a fringe projection method. It surpasses all the above mentioned systems in many parameters: rate of processing (10 seconds instead of 1 - 2 minutes), the spatial resolution of a restored surface, a level of automation of processing. 2. Aim

To estimate short term changes in the shape of a trunk dorsal surface and the position of a patient's body in three-dimensional space by computer-optical topography after surgical correction of congenital deformation with Cotrel-Dubousset instrumentation. 3. Material and methods The results of the surgery of patients with congenital scoliosis treated with various modifications of GDI are studied. The data of standard radiographic and clinical examinations,

212

M. V. Mikhoilovsk\ et al. / Cotrel-Dtihousset Instrumentation tCDIl

and computer optical topography estimations of shape of a trunk dorsal surface before and after surgery were used for analysis of outcomes in 27 operated patients with congenital scoliosis (22 girls and 5 boys) at the age of 8 - 36 years (mean age 16,4 years). In 78 % of cases the deformations were caused by multiple anomalies of vertebral development. Results of complex examination before and after surgery were analyzed. Standing spondilograms in two projections were performed before surgery and in a week after it. The sizes of scoliotic arches, kyphosis and lordosis were determined according to Cobb. Rotation of the apex vertebra was not studied as the application of GDI for congenital spine deformations does not assume "derotation manoeuvre", and consequently, changes in this parameter (Dubousset, 1991). The computer optical topography was performed at standard follow-up terms and contained 90 parameters of shapes in two basic lateral and horizontal-sagittal planes, out of which only 11 parameters correlating with clinical and radiological data were selected for analysis. These parameters are the following: Frontal plane: Pelvic inclination -from 3,9° to 2,98° (-23,6%) Shoulder tilt -from 4,3° to 2,7° (-36,6%) Frontal balance-from 19,6MM to 18,9MM(-3,9%) Sagittal plane: Thoracolumbar inclination -from 30,53° to 19,62°(-35,7%) Thoracic kyphosis height -from 35,5 MM to 29,9 MM (-15,6%) Lumbar lordosis height -from 34,3 MM to 26,9 MM (-21,5%) Pelvic inclination -from 22,5° to 20,9°(-7,5%) Sagittal balance -from 4,04° to 3,34° (-J7,3%) Horizontal plane: Primary curves apex rotation -from 36,7° to 26,3° (-28,4%) Volumetric asymmetry of the thorax —from 23,9MU to 18,6MM (-22,1%) Relative twisting of shoulder and pelvic girdles -from 6,6° to 4,6° (-30,5%) 4. Results Pre- and postoperative values of radiographic and topographical parameters in both groups of patients are presented in Tables 1 and 2. Sizes of scoliotic arches, kyphosis and lordosis and deformations determined on x-ray pictures correspond to the numerous results published in the orthopaedic literature and require discussion only in a context of their correlation with the computer topographical data. The initial average size of the spine scoliotic deformity was 80,3°, after operation it decreased up to 63,6°.The size of a kyphotic component initially comprised 84,0°,after operation-69,3°(Table 1). The radiological data were compared with the data received during computer - topographical examination (Table T).

213

M. V. Mikhailovsky et al. / Cotrel-Dubousset Instrumentation (CDI)

Table 1. X-ray parameters. Parameter No 1. Primary curve (°) 2. Secondary curve (°) 4. Kyphosis (°) 3. Lordosis (°)

Before 80,3 61,8 84,0 49,7

After 63,6 52,0 69,3 43,6

Alter 14,13

9,2 6,5 12,3

% -20,8 -15,9 -17,4 -12,6

Table 2. Topographical parameters before and after operation. No

1 Parameter

Before

After

Alter

%

Frontal plane

1

Pelvic tilt (°)

3,92

2,98

2,88

-23,6

2

Shoulder tilt (°)

4,27

2,7

11,6

-36,6

3.

Frontal balance (mm)

18,9

8,73

-3,9

8,73 8,04

19,62 29,9 26,9 20,85 3,34

9,7 2,8

-35,7 -15,6 -21,5 -7,5 -17,3

9. 10

19,6 Sagittal plane Thoraco-lumbar region's inclination (°) 30.53 Thoracic kyphosis height (mm) 35,5 Lumbar lordosis height (mm) 34,28 Pelvic sagittal inclination (°) 22,55 4,04 Sagittal balance (mm) Horizontal plane Primary curves apex rotation (°) 36,68 Volumetric asymmetry of the thorax (mm) 23,98

26,26 18,63

9,04 4,78

-28,4 -22,1

11

Horizontal balance (°)

4,56

3,5

-30,5

4. 5. 6. 7. 8.

6,56

6,79

Computer optical topography of a patient's trunk in the frontal plane has shown, that in the nearest postoperative period GDI substantially reduces an inclination of the shoulder girdle (parameter 2), essentially reduces an inclination of the pelvis (parameter 1) and to a lesser degree influences the frontal balance (parameter 3). Correction with polysegmental instrumentation normalizes the position of the scapulae and corrects a shoulder tilt. Reduction of the shoulder girdle inclination (parameter 2) is probably related to the influence of CDI on the rigid thoracic arch. Parameters 1 and 3 are not changed much, probably due to initially small misbalance of the trunk at the expense of compensating lumbar counter-curve. In the sagittal planes distinct positive dynamics of correction of the thoracolumbar curve (parameter 4) is revealed, which is in its turn related to height reduction of the thoracic kyphosis (parameter 6) and reduction of lumbar lordosis (parameter 7). The correction of pelvic tilt is insignificant (parameter 5). Sagittal parameters strictly correspond to the magnitude of kyphosis correction and characterize restoration of sagittal balance of the trunk (parameter 8). Apex rotation of a main arch and volumetric asymmetry of the rib cage (parameters 9 and 10) characterize derotation effect of CDI and changes in parameters in the horizontal plane. Although derotation manoeuvre is not used for congenital deformations, we managed to achieve the effect of passive derotation. Perhaps, this effect of CDI application is caused by the direct influence of hooks installed in intermediate vertebrae on the apex of deformation. Changes in

M. V. Mikhailovsk\ et al. / Cotrel-Dnhoussei Instrumentation (CDI}

parameters 10 and 11 are explained by the indirect action of corrective efforts on the shape of the rib cage via the main arch (Fig. 1).

Fig.l. Back shape of patient before and after surgery with CDI, left panel - before, right panel - after surgery.

5. Conclusions The computer optical topography has allowed to estimate inherent changes in the trunk position of a patient in three-dimensional space and to receive an additional parameter, which cannot be received by radiography - a change of the shoulder girdle position relative to the pelvis in the horizontal plane (parameter 11). This parameter evidently gives an opportunity of threedimensional correction of congenital deformations of the spine with circular fusion (360° fusion) and CDI installation. This instrumentation provides normalization of the trunk balance and a significant cosmetic effect. Computer optical topography confirms significant improvement of a large number of parameters in surgical correction of congenital spinal deformities. The course of the adaptation of patients to new conditions of static and dynamics resulted from the correction of the spine will prove within time and further researches.

M. V. Mikhailovsk\ et at. / Cotret-Dubousset Instrumentation (CD!)

215

References 1. 2.

3. 4. 5.

6.

7.

8. 9. 10.

Cotrel Y, Dubousset J, Guillaumat M: New universal instrumentation in spinal surgery. Clin Orthop, 1988, N 227, pp 10-23 Csongradi JJ, Bleck EE: Moire toporgaphy: use in scoliosis observation. In Moire fringe topography and spinal deformity. Edited by Drerup B., Frobin W., Hierholzer E. Stuttgart, New Jork, Gustav Fischer Veriag. 1983, pp 141-148 Drerup B, Hierholzer E: Back shape measurement using video raster-stereography and threedimensional reconstruction of spinal shape. Clin Biomech, 1994, v.9,Nl,pp 28-36 Dubousset J: Congenital kyphosis. In. Bradford DS, Hensinger RM (eds): Pediatric Spine. New York. The Theieme- Stratton, 1985. Edgar MA, Bettany JA, Ransford AO, Harrison DJ: ISIS assessment of costoplasty: Preliminary results. Surface Topography and Spinal Deformity. Edited by-Albert! A, Drerup B, Hierholzer E. Gustav Fischer Veriag, Stuttgart, Jena, New Jork, 1992, pp 83-88 Lecire C, Skalli W, Zeiler R, Dubousset J, Lavaste F: Three-dimensional per-operative opto-electronic analysis of Cotrel-Dubousset surgery. Research into Spinal Deformities 2. Edited by I.A.F.Stokes, 1998, pp 118-121 Mikhailovsky M, Sarnadsky V, Novikov V: Three dimensional correction with CD instrumentation and pure Harrington distraction in the treatment of idiopathic scoliosis. GICD-s 3rd Eastern European Forum. St. Petersburg 1999. Takasaki H: Moire Topography. AppI Opt, 1970, v.9, N 6, pp 1467-1472 Turner-Smith AR: A television/computer three-dimensional surface shape measurement system. J.Biomechanics, 1988, v.21, pp 515-529 Willner S: Spinal pantograph - a non-invasive anthropometric device for describing postures and asymmetries of the trunk. J Pediatr Orthop, 1983, v.3, pp 245-249

216

Th.R. ('-mas tEd i Research into Spinal Deformities 4 !(>S /••;•2

Three-dimensional correction with CD Instrumentation and Harrington rod in the treatment of idiopathic scoliosis M.V. Mikhailovsky MD V.V. Novikov, V.V Sarnadsky PHD Research Institute ofTraumatology and Orthopaedics, Department of Spinal Surgery for Children and Adolescents, 630091 Frunze str. 17 Novosibirsk. RUSSIA 1. Introduction The Cotrel-Dubousset instrumentation developed in 1983 is widely applied in scoliosis surgery. Its high efficiency is convincingly proved to numerous researches [5,6 7]. However, Harrington instrumentation in its modifications (Harrington-Luque. Resina. Drummond ea.) is widely used in scoliosis correction. The comparative analysis of these methods is still an object of discussion [2, 11]. In the last years the methods of three-dimensional assessment of the dorsal surface of patients trunk are widely applied for comparison purposes of results of surgical intervention [ 1 . 4, 8]. Among them the electron optical topographical system ISIS [9] based on computer and television engineering, and also Formetic [3] and Quantec [10] in which basis the rasterstereography are most widely used. In Novosibirsk Research Institute of Traumatology and Orthopaedics in I 994 the electron-optical topographical system 'Computer optical topographer' (COMOT) was created on the basis of a method of a projection of strips and spatial detecting of a phase. It surpasses the above mentioned systems in a lot of parameters: speed of processing (1 0 seconds instead of 1 -2 minutes), spatial sanction of a restored surface, level of automation of processing. 2. Aim

The aim of the present research is the assessment of the results of the surgical treatment ol patients with adolescent idiopathic scoliosis (AIS) with the help of COMOT on two basic directions: the change of relief of the back surface of a trunk and the position of a patients' body in three-dimensional space after correction of the deformation by GDI and Harrington and during follow-up period 3. Material and methods Clinical charts, X-ray films and computer optical parameters of 71 patients with adolescent idiopathic scoliosis were investigated All of them were operated in the department of spinal surgery forthildren and adolescents in the period since January 1998 till February 2000. Depending on the method of operative treatment the patients were divided in two groups. 39

M. V. Mikhailovsk\ et al. / Three-Dimensional Correction with CD Instrumentation

217

patients, operated with application of GDI where the first group. There were 37 girls and 2 boys. Patients operated with application of Harrington rod with addition as wire loops on Drummond have come in second one. There were 31 girls and 1 boy. The average age of both groups was 14.1 years (range I 2,2 to 21,5). In 26 cases of GDI group and in 7 cases of the Harrington group the intervention was one-staged, in 13 others of GDI and 25 others of Harrington anterior discectomy and interbody fusion with autobone were performed in one session. Pre- and postoperative (one week) investigation included standing AP and lateral radiograms. Cobb angles were identified for scoliotic kyphotic and lordotic curves, apical vertebrae rotation was measured according to the Nash-Moe technique. The procedure of computer-optical topography: The patient stands before a reference plane by his back to the telechamber. With the help of a projector the picture of black-and-white vertical strips is projected on the patients' back on the surface of which strips image is deformed. This picture is processed in the computer with the special program during 10 seconds. The results are submitted in two basic forms - "lateral analysis" and sagittal-horizontal analysis. Both forms contain in total 90 parameters, from which for the present research 11 are selected: Frontal Plane • pelvic tilt • shoulder tilt • frontal balance (clinical analogue is the distance from a plumb line omitted from processus spinosus C7 to the interbuttock fold) Sagital plane • thoraco-lumbar region's inclination • pelvic sagittal inclination • kyphosis • lordosis • sagittal balance Horizontal Plane • primary curve's apex rotation • volumetric asymmetry of thorax • horizontal balance

4. Results Preoperative, postoperative and 1 year after value of radiological parameters in both groups of the patients are presented in table 1. All radiological parameters in the Harrington group decreased after operation (from 6,5% to 56,2%). All parameters got some worse lyear after operation (from 2,5% to 1 5%) and thoracic kyphosis increased on 31,5%. GDI group has the same changes (decrease from 1 3% to 5 1 %), but kyphosis increased on 1 9% right away after operation. All parameters increased 1 year after operation insignificantly (4%- 11 %), and overall kyphosis was higher in GDI group than in Harrington group (28° and 21 ° respectively). X-ray parameters were compared with computer optical parameters (Table 2). In GDI group all parameters in the frontal plane became better after operation (from 7% to 49%). In Harrington group pelvic tilt and frontal balance got worse (39% and 24% respectively). Nevertheless, shoulder tilt decreased significantly. In GDI group parameters didn't change noticeably 1 year after operation (shoulder tilt decreased 7%, frontal balance 11 % and pelvic tilt

Table 1. X-ray parameters after operation CDI

Harrington

Parameter

Before

After

%

1 year

%

Before

After

%

1 year

%

Primary curve

68,6

33,6

-51

36,1

3,6

76,5

33,5

-56,2

39,8

8,2

Secondary curve

55,9

31,1

-44,4

37,3

11,1

54,7

25,7

-53

33,9

15

Kyphosis

22,5

26,7

18,7

28,2

6,7

16,8

15,7

-6,5

21

31,5

Lordosis

48,6

42,5

-12,6

45,1

7,2

44,7

38,6

-13,6

39,7

2,5

Primary curve apical rotation

29,4

22,9

-22,1

24,1

4.1

35,6

27,1

-23,9

29,8

7,6

Secondary curve apical rotation

20,3

15,9

-21,7

17

5.4

22

16,8

-23,6

18,2

6,4

Table 2. Topographical parameters before and after operation CDI

Harrington

Parameter Before

After

%

1 year

%

Before

After

%

1 year

%

Frontal plane Shoulder tilt °

3,9

2

-49

1,7

_7

5,7

1,1

-81

1,7

11

Pelvic tilt °

1,6

1,4

-13

1,5

7

2,3

3,2

39

1,5

-74

Frontal balance (mm)

16,3

15,2

-7

13,4

-11

14,3

17,7

24

10,9

-48

Sagittal plane Thoraco-lumbar region's inclination °

17

10,5

-38

14,1

21

13,2

9,1

-31

10,2

8

Pelvic sagittal inclination °

25,3

18,2

-28

22,5

17

24,8

19

-24

19,8

3

Kyphosis (mm)

26,1

27,3

5

27,9

2

19,1

24,3

27

20,8

-18

Lordosis (mm)

27,9

21,5

-23

22,7

4

21,8

15,4

-29

17,5

10

Sagittal balance °

3,1

2,2

-29

2,4

6

2,8

2,2

-21

1,3

-32

Horizontal plane Primary curve apical rotation °

36,8

11,4

-69

23,7

33

27,5

17,4

-37

25,7

30

Volumetric asymmetry of thorax (mm)

18,6

8,1

-56

16,6

46

17,2

12,4

-28

19,2

40

Horizontal balance °

3,4

3,8

12

3

-24

6,5

6,8

5

2,8

-62

M.V. Mikh(iilo\'sk\ ct til. / Tlircc-Dimcnsutnal Correction with CD Instrumentation

increased 7%). In Harrington group parameters, that have got worse after operation, became much better I year later (from 48% to 74%). In sagittal plane all parameters decreased in the GDI group, except for kyphosis (23%38%). Sagittal balance restored significantly (on 29%). Only pelvic sagittal inclination and thoracolumbar region's inclination changed 1 year after operation (increase of 17% and 21% accordingly). This reflects the improvement of the sagittal plane. In the Harrington group the same changes occurred after operation (decrease on 21 %-31 %), but 1 year after operation sagittal balance restored (on 32%) and kyphosis decreased (on 18%). It doesn't reflect the improvement of the trunk profile. In horizontal plane primary curve apical rotation and volL-etric asymme~y of thorax decreased significantly in GDI group (on 69% and 56% accordingly), horizontal balance got worse insignificantly (on 1 2%). Partial restoration of these parameters occurred 1 year after operation (apical rotation on 33% and volumetric asymmetry of thorax on 46%), but horizontal balance became better (on 24%). In Harrington group primary curve apical rotation and volumetric asymmetry of thorax decreased too (on 37% and 28% accordingly), but horizontal balance didn't change. Nevertheless, these parameters returned 1 year after operation to that before and even more (apical rotation increased on 30% and volumetric asymmetry of thorax on 40%). Horizontal balance decreased significantly 1 year after operation (on 62%). 5. Conclusions COMOT allows not only to study features of a relief of dorsal trunk surface of the patient with high accuracy, but also to receive the information concerning a position the patient's body in three-dimensional space. Correction of adolescent idiopathic scoliosis with Cotrel-Dubousset and Harrington instrumentation leads to pronounced changes of back shape and 3-D trunk balance (Fig. 1 -6). Nevertheless, GDI leads to more even improvement of all COMOT parameters, than Harrington. Moreover, the changes during the follow-up period after GDI less than Harrington. That give a chance to prognosticate the changes in patient's trunk after surgical treatment of adolescent idiopathic scoliosis. Partial loss of correction during the follow-up period leads to back shape and trunk balance changes more than radiological changes. It tells about more deep mechanism of patient's trunk adaptation to surgical intervention than simply mechanical resistance to corrective forces. CDt is more complex and has an opportunity of applying distraction, contraction, translation and derotation simultaneously. It is more rigid in all planes and can used in correction of severe scoliosis with double curves and kyphosis. Moreover, Harrington instrumentation leads to severe changes of back shape and trunk position in three-dimensional space during a long time after surgical correction of idiopathic scoliosis. So it makes modern instrumentation like CD as more preferable than Harrington rod. References 1 .

2.

Bettany J., Forbes H., Edgar M., Harrison D. The ISIS experience at the Royal National Orthopaedic Hospital // Surface Topography and Spinal Deformity. Proceedings of the gth International Symposium. Estoril: Fischer, 1992. P.70-75. Burwell R.G., Jacobs K.J., Polak F.J., Webb J.K., Wqjcik A.S., Wytbers D.J. The back hump after Cotrel-

M. V. Mikhailo\'sk\ ct cil. / Three-Dimensional Correction with CD Instrumentation

Fig.l Back shape of patient before GDI

Fig.2 Back shape of patient after CDI

Fig.3 Back shape of patient 1 year after CDI

10. I1

221

Fig.4 Back shape of patient before Harrington

Fig.5 Back shape of patient after Harrington

Fig.6 Back shape of patient 1 year after Harrington

Dubousset, Harrington-Luque and Zielke instrumentation // Surface Topography and Spinal Deformity. Proceedings of the gth International Symposium. Fstoril: Fischer, 1992. P. 180-195. Drerup B., Hierholzer E. Back shape measurement using video rasterstereography and three-dimensional reconstruction of spinal shape. Clin Biomech, 1 994,9, 1 , pp 28-36. Edgar M.A., Bettany J.A., Ransford A.O., Harrison D.J. ISIS assessment of costoplasty: Preliminary results. In: Alberti A, Drerup B, Hierholzer B (eds) Surface Topography and Spinal Deformity. Gustav Fischer.Stuttgart, 1992, pp 83-88. Krismer M., Bauer R., Sterzinger W. Scoliosis correction by Cotrel-Dubousset in-strumentation. The effect of derotation and three dimensional correction // Spine.-1 992.-Vol. 17, No8.-P.263-269. Puno R.M., Grossfeld S.L., Johnson J.R., Holt R.T. Cotrel-Dubousset instrumentation in idiopathic scoliosis /I Spine.-1992.-Vol J7 J~o8.-P.258-262. Richards B.S., Birch J.G., Herring J.A., Johnston C.F., Roach J.W. Frontal plane and Sagittal plane balance following Cotrel-Dubousset instrumentation for idiopathic scoliosis // Spine.-1989.-Vol 14. No7.-P.733-737. Tredwell S.J., Rose R., Sawatzky B.J. ISIS review of Cotrel-Dubousset instrumentation for adolescent idiopathic scoliosis. In: Alberti A., Drerup B., Hierholzer F. (eds) Surface Topography and Spinal Deformity. Gustav Fischer, Stuttgart, 1992, pp 1 16-1 18. Turner-Smith A.R. A television/computer three-dimensional surface shape measurement system. J Biomechanics, 1988, 21, pp 515-529. Wojeik A.S., Phillips G.F., Mehta M.H. Recording of the back surface and spinal shape by the Quan~c imaging system - a new technique in the scoliotic. 1994. Wojeik A.S., Webb J.K., Burwell R.G. Harrington-Luque and Cotrel-Dubousset instrumentation for idiopathic thoracic scoliosis. A postoperative comparison using segmental radiologic analysis /I Spine.-1990.-Vol J_5 No5.-P.424-431.

Tit B. (jn\ii

~y \y /^

_.^TV~"~!

0.00

0.20 0.40 0,80

0.80

1.00

1.20

1.40 1.60 1.10

2.00

2.20 2.40 2.00 2.80

Tlmt.MC

—FSN

—-FP

Shoulder girdle (GH) and pelvic (GP) rotation In the horizontal plane

0,00

0.20 0,40 0,60

0.60

1.00 1,20

1.40 1.60 1.80 2.00 2.20 2.40 2.80

2.80

Tlm«,i»c

-•-GH

->-GP

Trunk and pelvic Inclination In the sagittal plane

0.00

0.20 0,40 0.60 0,80 1,00 1.20

1.40 1.60

1.80 2.00 2.20 2.40 2.60

Time, Me

2.80

-—SNAN

-*-ANS

Lumbar lordoele (LA2) and thoracic kyphosla (KA2)

-*- LA2

— KA2

Lateral deviation of the aplnoua proceaaea to the l*ft (DSDL) ind to th* right (DSDR) In a frontal plan*

A ;>f/v\ /*'*-_

f.iSf \.v y iXxv/ y Iv>^*"•"•\ /

r— %.

y----^ I ^\==s^fL—

— OSDL -.-DSDR

Fig.6. Movement of a patient's trunk in three planes and changes in the spine shape during walking

V..V. Santddski\ cl cr ni / Accuracv of' Rasierstereographv versus Radiograph*

The patients were examined pre- and postoperatively by rasterstereography and radiography in relaxed standing posture. The radiographs were digitized according to the method of Drerup [6,7]. This method allows an accurate determination of lateral deviation, Cobb angle and vertebral rotation. In particular the postoperative measurement of vertebral rotation is more precise than conventional non-digital methods owing to the calculation of smooth curves instead of pointwise segmental measurements. The similarity of rasterstereographic spinal reconstruction and the radiographic skeletal deformity was quantified by means of best-fit superimposition of the two curves and calculation of the root mean square (rms) differences of corresponding lateral deviation and rotation curves according to the method of Drerup and Hierholzer [8,9,10], see Fig. 1. Instead of local features the whole shape of both curves was taken in account.

Fig.l Comparison of radiographic and rasterstereoraphic spine curves before and after anterior surgery (52° thoracolumbar)

The location of vertebra prominence used for the longitudinal fitting of the

L. Hackenberg et al. /Accuracy of Rasterstereography versus Radiography

243

rasterstereographic curves is determined automatically, but slight manual corrections (±30mm) could improve the results. This has to be attributed to the fact that the position of C7 may deviate from the location of the bulge produced by its spinal process. Moreover the vertebra prominence may even be produced by C6 or Tl. Furthermore, different torsions between pelvis and shoulder in the relevant rasterstereographs and radiographs were considered as systematic errors due to possible posture variations and corrected before the curve comparison (correction of trunk torsion). In addition to the calculations of the curve comparisons the correction of the Cobb angles were determined from the digitised radiographs. 3. Results T he Cobb angles of the instrumented primary curves of the deformities could be reduced from 57.2 F (52-88 F) to 17.2° (6-34 F). The non-instrumented thoracic secondary curves corrected spontaneously from 34.5 F (16-48 F) to 21.5 F (7-43 F).

Table 1: Comparison of lateral deviation and vertebral rotation curves measured from rasterstereographs and digitised radiographs Note: A few rasterstereographs and radiographs were not taken on the same day, therefore some radiographs were compared with more than one rasterstereograph.

For the curve comparisons 149 radiographs (48 preoperative) were compared with 173 rasterstereographs. A few of them could not be taken on the same day. Therefore some radiographs were compared with more than one rasterstereograph. The comparisons of the lateral deviation curves showed a rms difference of 6.4 mm pre- and 3.4 mm postoperatively. The comparisons of the vertebral rotation curves without correction of systematic trunk torsion showed a rms difference of 5.3° preoperatively and 4.1° after surgery. With correction of trunk torsion the rms difference was 4.5° pre- and 3.2° postoperatively (Table 1). Particularly poor

244

L. Hackenherg el al. / Act uracv ofRastersiereograph\ versus Radiograpln

results of the curve comparisons in the preoperative group were analysed regarding the sources of error. The underestimation of the rasterstereographic vertebral rotation in the apical region of the deformities in the automatic reconstruction of the spine was a frequent problem in severe scoliosis and was considered to be the most important reason for the limited accuracy in the preoperative group. 4. Discussion A technique for a fast and objective quantification of the postoperative cosmetic improvement and both vertebral and back surface derotation appears to be helpful in scoliosis surgery. This investigation proved a good precision of the method in scoliosis corrected and fused by anterior surgery. The rms difference of lateral deviation and vertebral rotation is comparable with that found in scolioses below 50 F Cobb. This could be expected because after surgery the Cobb angles were lower than 50 F in all cases and no posterior implants or scars disturbed an accurate back surface analysis. The results of the comparison of the preoperative radiographic and rasterstereographic curves showed higher rms differences compared with those of scolioses below 50 F Cobb and of postoperative scolioses. In these severe scoliosis with Cobb angles higher than 50° the rasterstereographic curve reconstruction is reliable but its accuracy is limited to 6.4 mm lateral deviation and 4.5 F vertebral rotation on average. The comparison of MRI and rasterstereography in another examination [11] revealed that an underestimation of the vertebral rotation particularly at the apex causes the reduced accuracy of rasterstereography in severe scoliosis. 5. Conclusion The accuracy of rasterstereography in scoliosis after correction and fusion by anterior surgery is good and comparable with that of non-surgically treated deformities with similar Cobb angles. The accuracy in severe idiopathic scoliosis with Cobb angles of more than 50° is satisfactory. In future, the precision of the device may be improved by comparing MRI scans with rasterstereographs and developing new mathematical models. The authors hope to significantly reduce the postoperative radiation exposure of surgically treated patients with idiopathic scoliosis. References 2.

U. Liljenqvist, H. Halm, E. Hierholzer, B. Drerup, M. Weiland. Three-dimensional surface measurement of spinal deformities using video rasterstereography. Zeitschrift fur Orthopedic und ihre Grenzgebiete 1998; 136:57-64

3.

B. Drerup, E. Hierholzer. Back shape measurement using video rasterstereography and three-dimensional reconstruction of spinal shape. Clinical Biomechanics 1994; 9:28-36

4.

K. Zielke. Ventral derotation spondylodesis. Results of treatment in cases of idiopathic lumbar scoliosis. Zeitschrift fur Orthopedic und ihre Grenzgebiete 1982; 120:320-329

L. Hackenberg et al. /Accuracy of Rasterstereography versus Radiography

245

5. H. Halm, U. Liljenqvist, T. Niemeyer, D.P.K. Chan, K. Zielke, W. Winkelmann. Halm-Zielke instrumentation for primary stable anterior scoliosis surgery: Operative technique and 2-year results in ten consecutive adolescent idiopathic scoliosis patients within a prospective clinical trail. European Spine Journal 1998; 7:429-434 6.

M. Morin Doody, J.E. Lonstein, M. Stovall, D.G. Hacker, N. Luckyanov, C.E. Land. Breast cancer mortality after diagnostic radiography: Findings from the U.S. Scoliosis Cohort Study. Spine 2000; 25:2052-2063

7.

[B. Drerup. Principles of measurement of vertebral rotation from frontal projections of the pedicles. J. Biomechanics 1984; 17:923-935

8.

B. Drerup. Improvements in measuring vertebral rotation from the projection of the pedicles. J. Biomechanics 1985;18:369-378

9.

B. Drerup, E. Hierholzer. Evaluation of frontal radiographs of scoliotic spines-Part 1: Measurement of position and orientation of vertebrae and assessment of clinical shape parameters. J. Biomechanics 1992; 25:1357-1362

10. B. Drerup, E. Hierholzer. Evaluation of frontal radiographs of scoliotic spines-Part 2: Relations between lateral deviation, lateral tilt, axial rotation of vertebrae. J. Biomechanics 1992; 25:1443-1450 11. B. Drerup, E. Hierholzer. Description of scoliotic deformity by modulated sinusoidal functions. Threedimensional Analysis of Spinal Deformities (ed. by D'Amico M, Merolli A, Santambrogio GC), IOS Press/Omsha Amsterdam/Tokyo 1995; 113-118 12. E. Hierholzer, L. Hackenberg. Three-dimensional shape analysis of the scoliotic spine using MR tomography and rasterstereography (this volume)

246

Th.BGnvastEdt Research into Spinal Deformities 4 IOS Press. 2

14

F

161

47

10

11

F

133.5

37

Table 1 : general information about patients 2.2 3D Geometry For each patient, front and profile X-rays were taken in a specific calibration device in order to get the radiographic environment . X-rays were scanned with a VIDAR® scanner and the radiographic images were processed with a specific software to obtain 3D reconstruction of spine and pelvis using NSCP method . Accuracy of such reconstruction has been assessed in previous studies for the shape of the vertebrae and pelvis (mean point-surface error 1.5 nun), t h e i r orientation (mean values of rotation : lateral 0.4 . sagittal 0.7 . axial 1.4 ). and the 3D position of vertebral body geometric center i 1 m m ) . 2.3 Foot pressure measurement The basis of stereoradiographic device is equipped by a ZEBRIS® plate-form ( F i g u r e 2 ) . This system permits foot pressure measurement using sensors of 1cm 2 in a sensor area of 32 \ 47 cm 2 , The measurement accuracy is about +/- 5cf.

Static measurement using this platform yields location of projection of the patients' center of gravity. The vertical line based on that point is named GL. Furthermore, the coordinate system of the force platform was located with regard to that of the stereoradiographic evice in order to assess GL location with regard to spine and pelvis. The accuracy was estimated to +/- 1 cm. 2.4 Reference group: A previous study conducted in collaboration with "Tripode" hospital (Bordeaux, France) with the same protocol concerned 34 asymptomatic adult volunteers (mean age 30,5 yrs, range 2 I -53)\ These subjects were considered as a reference group.

2.5 Data processing: Various clinical indices were calculated to characterize the vertebral and spinal deformity as well as patient's posture and imbalance. In the present study we focused on the distance between each vertebra center and the GL. 3. Results A great variability was found among the 10 measured patients. To illustrate this variability, we focused the results on 3 patients who were considered as particularly demonstrative. Figure 4 presents the 3D reconstruction of the spine and the pelvis with regards to the GL tor these 3 patients. Figure 5 shows the projection of vertebra center position w i t h regards to GL. These data are compared with reference group results. Patient 10 has a mild thoracolumbar 5° curve (D11-L4). Although a slight left deviation of the spine is observed, the top view of its vertebral line keeps within those of the reference group, both in the sagittal and frontal directions. Patient 05 has a mild thoracolumbar 20° curve (D9-L2). The frontal view indicates this curvature and a slight right imbalance. The sagittal view shows reduced lumbar curve. On the top view, the vertebral line projection is situated at the borderline of reference group lines. Third, patient 09 has a double curvature (D5-D1 1 and Dl 1-L4, respectively 10° and 14"). The frontal view shows small right global imbalance of this patient. The sagittal view indicates reduced both lumbar and thoracic curves. On the top view, the location of the projection of the vertebral line is also situated at the borderline of reference group data.

-V Champain et al. /Geometric and Postural Analvsis

4. Conclusion The results of this study underline the advantage of combining 3D reconstruction with force pressure measurements in the same coordinate system. This innovative protocol gives the possibility for clinicians to have qualitative observation of the global equilibrium of spine and pelvis for scoliotic patients and quantitative parameters for this observation. This protocol could be used in long-term follow-up study of patients with mild idiopathic scoliosis, in order to better understand biomechanical parameters, which influence scoliosis aggravation.

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5. Acknowledgments The authors gratefully thank « Fondation Yves Cotrel pour la recherche en pathologic rachdienne », Institut de France, for its financial support. References 1.

Clerc AL, Mitton D, Skalli W. Contribution a la semi automatisation des reconstructions 3D du rachis scoliotique et etude de la precision des parametres quantitatifs de la scoliose. 2000, DEA de Biomecanique, ENSAM, Paris. 2. Dumas R, Mitton D, Steib JP, De Guise JA, Skalli W. Pre and Post 3D modeling of scoliotic patients operated with in situ contouring technique. 2002, International Meeting of the IRSSD, Athens, Greece. 3. Duval-Beaupere G. Rib hump and supine angle as prognostic factors for mild scoliosis. Spine 1992; 17:103-7. 4. Duval-Beaupere G, Lamireau T. Scoliosis at less than 30 degrees. Properties of the evolutivity (risk of progression). Spine 1985; 10:421-4. 5. Gangnet N, PomeroV, Dumas R, Skalli W, Vital JM. Variability of the spine and pelvis location with respect to the gravity line: a 3D stereradiographic study using a force platform. Surg. & Radio Anat. 2001; submitted 6. Graf H, Hecquet J, Dubousset J. 3-dimensional approach to spinal deformities. Application to the study of the prognosis of pediatric scoliosis. Rev Chir Orthop Reparative Appar Mot 1983; 69:40716. 7. Labelle H, Dansereau J, Beliefeur C, Jequier JC. Variability of geometric measurements from threedimensional reconstructions of scoliotic spines and rib cages. Eur Spine J 1995; 4:88-94. 8. Mitton D, Dumas R, Laporte S, Leborgne P, Bataille Ph, Quidet D, Skalli W. Simplified calibration system for stereordiography in scoliosis. 2000, International Meeting of the IRSSD, Clermont Ferrand, France. 9. Mitton D, Landry C, Veron S, Skalli W, Lavaste F, De Guise JA. 3D reconstruction method from biplanar radiography using non-stereocorresponding points and elastic deformable meshes. Med Biol Eng Comput. 2000; 38:133-9. 10. Mitulescu A, Semaan I, De Guise JA, Leborgne P, Adamsbaum C, Skalli W. Validation of the nonstereo corresponding points stereoradiographic 3D reconstruction technique. Med Biol Eng Comput 2000; 38:133-9. 11. Mitulescu A, Skalli W, Mitton D, De Guise JA. Three-dimensional surface rendering reconstruction of scoliotic vertebrae using a non-stereo corresponding points technique. Euro Spine J 2000, in press. 12. Sahlstrand T, Petruson B, Ortengren R. Vestibulospinal reflex activity in patients with adolescent idiopathic scoliosis. Postural effects during caloric labyrinthine stimulation recorded by stabilometry. Acta Orthop Scand. 1979; 50:275-81.

Tli.B. C/Y/u/A/£[4). It allowed a reconstruction of a very limited number of reconstructed points per vertebra because of the necessity to have anatomical landmarks identifiable on both radiographs (stereocorresponding points). A real advance in this technique was the development of the NSCP algorithm [9]. This algorithm, based on an a priori knowledge of the 3D mean generic object gave the possibility to reconstruct non-stereocorresponding points. This allowed having 3D representations with accuracy close to 3D CT-scan reconstructions191'1'01. Despite of this good accuracy, personalised reconstruction was not enough morpho-realistic because of the limited set of points defining the generic object (150 to 214 points per vertebra). The aim of this study was to propose and validate a method allowing very detailed and accurate personalised reconstruction (2000 points per vertebra), using EOSi system. 2. Materials and Methods 63 dry vertebrae coming from the Laboratoire d'Anatomic des St Peres (Paris, France) were used for this study. These vertebrae were divided in 2 subsets. Subset A contained 1 non-pathologic vertebrae per level from C3 to L5 (i.e. 22 vertebrae). It was used to define a detailed generic object for each vertebral level and was not taken into account for the validation method protocol. Subset B, containing 36 non-pathological (10 inferior cervical vertebrae, 12 thoracic vertebrae and 14 lumbar vertebrae) and 5 scoliotic vertebrae was used for the validation protocol. We briefly remain existing reconstruction method, which details have already been presented191, then we present the adaptation to improve morphorealism. The 3D-

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stereoradiographic reconstructions were obtained using the SCP, NSCP and kriging algorithms1181. Kriging consists in deforming a generic object with regard to a set of control points to fit to on a specific object containing some of the same identified control points. In this study, this method was extended to obtain 2000 points reconstructed models. The main steps and specificity of the current method will be given in the following parts. 2.1

Generation of Detailed Generic Object

Existing generic objects were taken from a database of 3D direct measurements (accuracy error< 0.2 mm) obtained in previous studies18"51'117"121. This database provided the average 3D geometry (10 to 30 vertebrae per level) for an approximately 200 points set per vertebral level. To improve the morphology definition of this existing generic objects described above, we used for each vertebral level a 3D CT-scan reconstruction containing up to 2000 points. The dry vertebrae coming from the subset A were all scanned in a CT-scan device at the Centre d'Imagerie Veterinaire (Billancourt, France) with the following CT settings: slices thickness of 1 mm and slice spacing of 0 mm. The 3D reconstruction was realised using the SliceOmatic® software by piling the CT slices of the vertebrae and using the standard marching cube reconstruction p]. At first, bone surfaces on each CT slice are recognised by an automatic segmentation of grey level, then a manually correction of the potential segmentation errors are realised and finally the 3D reconstruction is performed containing up to 2000 points. However this 2000 points CT-scan models are not usable for NSCP + kriging technique because they have no control points and they are not representative models of a vertebral level. On these CT-scan reconstructions, an infographic method [191 was applied to extract semiautomatically the set of points corresponding to the generic objects described above (150, 214 and 178 points for the cervical, thoracic and lumbar vertebrae respectively). These points were then associated with the CT-scan reconstruction in order to use them as control points for our future 2000 points models. Finally, the control points associated with the 2000 points specific mesh were kriged, on the corresponding average models to obtain a 2000 points average model for each vertebral level (Figure 1).

2.2

Validation of the method

The calibration of the radiological environment was realised with a modified DLT algorithm to fit to the specificity of the low dose digital systemtll] in order to obtain the 3D parameters of the radiographic device. For all specimens of the subset B, depending on the specificity of the vertebral level and the radiographs visibility, 20 to 28 landmarks per vertebra were identified, i.e. from 8 to 13 stereo-corresponding points and from 13 to 19 non-stereo-corresponding points.

2S8

.4. Le Bras ct al. / 3D Detailed Reconstruction of Vertebrae

Once the 3D co-ordinates of these controls points are obtained (DLT+NSCP), the deformation of the detailed generic object is realised using extrapolation and interpolation algorithms ("kriging"), which yields an approximate global shape of a given vertebra that is consistent with the 3D co-ordinates of the control points. Finally a detailed personalised model with 2000 points is obtained. All vertebrae were then CT-scanned and reconstructed with the same protocol reconstruction defined for the detailed generic object generation. The accuracy of this reconstruction technique protocol was evaluated at ± 1mm [7]. They were used as reference reconstruction for the comparison with the 3D detailed stereoradiographic model. The comparison consisted in superimposing the two models by using geometrical transformation (rotation, translation) and a least square matching method. On a first step, a qualitative comparison was performed to have an idea of how adequate the reconstructed shape is, when compared to the reference vertebral topology (CT scan). Moreover, visualisation of the superimposed reconstruction of the same vertebra makes visible the vertebral regions where maximum deviations may occur. On a second step, to quantify the accuracy of the stereoradiographic technique with regard to the reference technique (CT-scan), the results of the comparisons were expressed as point to surface distances. After superimposition, each point of the model (obtained from stereoradiography) was projected on the surface defined by the reference (obtained from the CT scan) in order to calculate the point to surface distance I91"01. The mean point to surface distance, the 2 RMS (2 Root Mean Square, representing the maximal error for 95 % of the points) and the maximum distance values (representing the isolated extreme values obtained for the entire sample) were evaluated. This comparison was processed on the entire set of 2000 points per vertebra for the whole sample with regard to 3D CT scan reconstruction. 3. Results A qualitative evaluation of reconstructed vertebrae was realised. An example is shown for a thoracic vertebra (figure 2).

The quantitative results of the point to surface comparisons between detailed stereoradiography reconstruction and CT scan technique are presented in Table 1 as mean, 2 RMS and maximum value and for the entire sample of 36 vertebrae and the scoliotic ones. Table 1; Results of the quantitative comparison between detailed stereoradiographic reconstruction and CT-scan reconstruction

Point to surface error (mm) Mean 2RMS Max Non-pathok>gical vertebrae (36 vertebrae)

0.9

2.2

5

5 Scoliotic vertebrae

1.1

2.5

6

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4. Discussion The qualitative evaluations of the reconstructed vertebrae proved realistic morphological shapes and quite similar to the CT scan ones. Moreover, this is the first study about stereoradiographic reconstruction accuracy considering the geometric specificity of each spine level visible on a classical spine radiograph (from C3 to L5). The quantitative results showed error comparable to previous studies (the previous more accurate one showed an average error of 1.1 ± 2.8 mm for lumbar vertebrae [IO] whereas the current models taking into account a very larger set of points. Indeed, approximately 2000 reconstructed points are evaluated for the current model versus only 178 points for the previous most detailed one l101. Therefore, this is a real improvement compared to all the previous stereoradiographic reconstruction method [1I>191>110]. These very encouraging results are certainly due in one way to the image quality permitting a good visibility of specific anatomical points and contours of the X-rayed vertebrae, and in an other way to the iterative control process allowing fitting the real radiograph contours with the retro-projected ones. But this capacity of control is only possible thanks to the high detail level of the 3D model, which allow a very realistic retro-projection. The maximal errors (~ 6mm) for certain cases could be explained by osteophyts on few vertebrae. Effectively, this reconstruction method using the deformation of a generic mean object can produce local deformation induced by a global deformation (case of a degenerative scoliotic pathology for example) but it can not take into account important local deformation caused by a local degenerative pathology. This fact could be explained by the limitation of the NSCP algorithm, which can deform the generic object only in the region where geometrical informations (anatomical landmarks identified by the operator) are sufficient. Nevertheless, integrating a non-stereocorresponding contours algorithm in the 3D-stereoradiographic reconstruction method could probably diminish the higher reconstruction errors. 5. Conclusion The results showed high accuracy of the detailed reconstruction models obtained from the low dose X-ray device. As the X-ray dose is significantly diminished and the personalised 3D geometric models seem to be quite accurate, this new 3D imaging technique could be a good alternative to existing techniques for the follow-up of scoliotic patients, allowing quantitative 3D analysis. Moreover this method could give a very detailed geometry for personalised finite element model, and thus showed a real progress in the planning of surgical acts. 6. Acknowledgements The authors thank A. Mitulescu for her technical advice as well as Biospace Instruments for financial support.

References 1 2 3 4

Aubin CE, Dansereau J, Parent F, Labelle H, de Guise JA (1997): Morphometric evaluations of personalised 3D reconstructions and geometric models of the human spine. Med Biol Eng Comput 35: 611-618 De Guise J.A., Martel Y., (1988): 3D biomedical modelling: merging image processing and computer aided design. IEEEEMBS 10th International Conference, New Orleans, pp. 426-427. Dubousset, J. (1992) : Importance of three-dimensional concept in the treatment of non scoliotic deformities. Proc. Int. Symp. 3D Scoliotic Deformities, Montreal, Quebec, Canada, pp. 302-311. Dansereau J. and Stokes, I.A.F. (1988) : Measurements of three-dimensionnal shape of the rib cage. J. Biomech., 21, pp. 893-901.

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Ismael B. (1995): Etude morphometrique des vertebres thoraciques.Memo\Te de DEA, LBM ENSAM, Paris 6 Kalifa G., Boussard J.M. (1996): L'appareillage de radiologie numerique dit Charpak. J. Radio!., pp 77-85 7 Landry C., de Guise J.A., Dansereau J., Labelle H., Skalli W., Zeller R. and Lavaste F. (1997): Analyse infographique des deformations tridimensionnelles des vertebres scoliotiques. Ann. Chir., 51, pp. 868874. 8 Maurel N. (1993): Modelisation geometrique et mecanique tridimensionnelle par elements finis du rachis cervical inferieur. These de doctoral en mecanique, LBM-ENSAM, PARIS. 9 Mitton D., Landry C., Veron S., Skalli W., Lavaste F., and de Guise J.A. (2000): 3D reconstruction method from biplanar radiography using non-stereocorresponding points and elastic deformable meshes. Med. Biol. Eng. Comput., 38, pp. 133-139. 10 Mitulescu A., Semaan I., de Guise J.A., Leborgne P., Adamsbaum G., and Skalli W. (2001): Validation of the non-stereocorresponding points stereoradiographic 3D reconstruction technique. Med. Biol. Eng. Comput., 39, pp. 152-158. 11 Mitulescu A. (2001). Contribution a la reconstruction tridimensionnelle du rachis et du bassin a partir de la ste~reoradiographie conventionnelle et basse dose (Charpak). These de Doctoral de I'ENS AM, Specialite Mecanique. 12 Parent S.et al. (2000): Morphometry of normal thoracic vertebrae. In CORS 2000. 13 Pearcy M J.,Whittte M.W.( 1982): Movements of the lumbar spine measured by three-dimensionnal X-rayanalysis. 3. Biomed Eng., 4, pp. 107-112.

14 PenJrioUe R. (1979): La scoliose: son aspect tridimensionnel in Mak)ine(Ed.), Paris. 15 Rainaut J J. (1994): Les scolioses. Ellipse (Ed.), Paris. 16 Selvik G., Olsson T.H., and Willner S. (1976): High accuracy analysis of movement of the spine with the aid of a roentgen stereophotogrammetry method. Biomechanics V-B. Edited by P.V. Komi, University Park Press, Baltimore Maryland, USA, 1976, pp. 502-507. 17 Semaan I.(1997): Etude morphometrique des vertebres lombaires.'MtmoiK de DEA (LBM, ENSAM, Paris). 18 Trochu F.(1993): A contouring program based on dual kriging interpolation. Eng. Comput.. 9, pp. 160177. 19 Veron S. (1997): Modelisation geometrique et mecanique tridimensionnelle par elements finis du rachis cervical superieur. These de doctoral en mecanique, LBM-ENSAM, Paris.

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Pre and Post 3D Modeling of Scoliotic Patients Operated with In Situ Contouring Technique R. Dumas(1), D. Mitton(1), J. P. Steib(2), J. A. de Guise(3), W. Skalli

CD

(/)

Laboratoire de Biomecanique, ENSAM-CNRS, Paris, France m Hopitaux Universitaires de Strasbourg, France Laboratoire de recherche en Imagerie et Orthopedic, ETS-CRCHUM, 5.1 Montreal, Canada Abstract. A three-dimensional segmental analysis was performed on the stereoradiographic reconstructions of ten right thoracic scoliotic patients. From the quantitative model of the spine and pelvis, the vertebral and intervertebral orientations were computed pre and post operatively. These orientations allow to determine the apical and junctional zones of the high thoracic, thoracic and lumbar curves. The apical zone corresponds to the maximum of vertebral axial rotation. Pre operatively, the tendency was T7 for the thoracic transverse apex with 20,/Eof axial rotation. The junctional zone corresponds to the maximum of vertebral lateral rotation and the maximum of intervertebral axial rotation. The tendency was T5 and T12 for the junctional vertebrae of the thoracic curve with, at both levels, 3QJE of vertebral lateral rotation and \OJE of intervertebral axial rotation. The surgical correction obtained by in situ contouring technique was evaluated through these 3D orientations. The vertebral axial rotation at the high thoracic, thoracic and lumbar apex was corrected with respectively 52%, 60% and 60%.

1. Introduction Several authors have pointed out the importance of the three-dimensional concept in scoliosis management. Among them, Perdriolle [1] and Dubousset [2] described a three dimensional segmental analysis. They observed, on one hand, the apical zones with maximum of axial rotation (without intervertebral axial rotation) and segmental lordosis in thoracic levels (intervertebral sagittal rotation) and, on the other hand, the junctional zones with maximum lateral rotation and intervertebral axial rotation. However, the three-dimensional deformity and the surgical correction evaluation are generally assessed plane by plane with global measurements (Cobb angles, lordosis and kyphosis). When multiplanar radiography is used, the reported measurement [3] is still global, with the plane of maximum deformity. As for the segmental (vertebral) orientation, the analysis is generally limited to the axial rotation, studied by frontal radiography, CT-scan [46], and intra-operative measurements [7, 8]. Moreover, the axial rotation remains controversial, due to variations and accuracy of computation methods and application difficulties. Using a quantitative stereoradiographic reconstruction [9], the purpose of this study is to assess, pre and post operatively, the segmental orientations, which are the characteristic of the curve (at the apical and junctional vertebrae).

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2. Materials and methods Ten scoliotic patients, 7 adolescents (13 to 19 years old) and 3 adults (33, 34 and 54 years old) presenting a basic right thoracic curve (5 double thoracic and lumbar and 5 triple curve patterns) were included in this study. The mean Cobb angle was 56° (range 36 ° to 78°). All patients underwent a surgical correction with the in situ contouring [10] technique at the Hopitaux Universitaires de Strasbourg. Pre and early post operative standing frontal and lateral X-rays were taken using a stereoradiographic device [11]. The patient's spine, from the 7th cervical vertebrae to the pelvis, was reconstructed in 3D by stereoradiographic methods using NSCP technique [9]. According to the SRS definition [12], the global axis system and the local (vertebral) axis systems were constructed. The vertebral orientation with regard to the global axis system and the relative inter-vertebral orientation (one vertebra with regard to the inferior one) were calculated using the LSA (Lateral, Sagittal, Axial) sequence [13]. The error of orientation has been evaluated in several combined rotations of a vertebral specimen and demonstrated 0.6 ° (0.5 °), mean and (SD) for lateral rotation, 0.7 ° (0.7 °) for sagittal rotation and 1.4 ° (1.3 °) for axial rotation. On three curves: the high thoracic (counter) curve (A), the thoracic curve (B) and the lumbar (counter) curve (C), the following characteristics were computed from the 3D reconstructions (see Figure 1): • • • •

In a junctional zone, the vertebra with the maximum/minimum Vertebral Lateral Rotation (VLR) In a junctional zone, the two consecutive vertebrae with the maximum/minimum Intervertebral Axial Rotation (IAR) In an apical zone, the vertebra with the maximum/minimum Vertebral Axial Rotation (VAR) In an apical zone (for thoracic curves only) the two consecutive vertebrae with minimum Intervertebral Sagittal Rotation (ISR)

Junctional Zone

Apical Zone ^"

Intervertebral Sagittal Rotation ISR Research into Spinal Deformities 4 /OS /Vov 22

The Role of Muscles and Effects of Load on Growth Ian Stokes and Mack Gardner-Morse Department of Orthopaedics and Rehabilitation University of Vermont, Burlington, VT 05405, USA

Abstract: If mechanical modulation of growth explains progression of scoliosis during adolescent growth, two elements of the 'vicious cycle' must be quantified. Firstly we must identify the magnitude of the asymmetrical loading imposed on the spine as a function of the scoliosis curve magnitude. Secondly, we must characterize the growth response of vertebrae and remodeling response of discs to this asymmetrical loading. Animal models are helpful to quantify the former, and extrapolation to the human spine should be possible once the parameters that influence the growth modulation response have been identified. Direct measurement of spinal loading is not currently feasible, so analytical modeling to estimate plausible loading states is required. Our simulations using a model that represents the lumbar spinal musculature and a spine with increasing degrees of spinal curvature suggests that there is a range of muscle activation strategies that may predispose to progression by the 'vicious cycle' mechanism, but other strategies can load the spine uniformly, or even reverse the asymmetrical loading that would lead to progressive deformity. However, the latter strategies have a physiological 'cost' associated with increased muscle stress and increased spinal loading.

1. Introduction The notion that progression of spinal deformity is mediated through mechanical modulation of growth, producing asymmetrically wedged vertebrae is intuitively attractive. It provides a supposed basis for scoliosis management with bracing, etc. The 'vicious cycle1 theory of scoliosis progression proposes that scoliosis causes loading of the spine that is asymmetrical in the coronal plane, and that vertebral growth and disc remodeling respond to the chronic presence of these asymmetrical forces. While qualitatively plausible, the 'vicious cycle' requires quantification of two crucial components: the magnitude of the loading distribution across discs and vertebral growth plates, and the growth response to mechanical loading of these structures. This paper focusses on quantifying the first of these presently qualitative elements. While it seems intuitively reasonable that coronal plane curvature (scoliosis) would produce coronal plane asymmetrical loading of the spine, this has not been proven. Direct measurement of the loading asymmetry in the spine during functional activities has not been attempted, since there is no available instrumentation capable of providing this information in live humans with scoliosis. Therefore, mathematical modeling was used in this study to estimate lumbar spinal loading as a function of the external effort of the modeled subject, the muscle forces required for equilibrium, and the trunk geometry including the degree of scoliosis. The trunk muscle activation strategy in persons with and

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without scoliosis is not known. In these simulations we used an optimization approach in which the muscle activation strategy had the objective to achieve spinal loading that either decreased or increased the asymmetry of vertebral loading, or did not take vertebral loading asymmetry into account. The goal of this study was to find whether there are muscle strategies that can produce coronal-plane symmetrical loading of the spine with scoliosis, and also to find the plausible magnitude of the spinal loading asymmetry for muscle strategies that do not take into account the loading symmetry of the spine. Furthermore, we investigated the physiological cost in terms of muscle forces and spinal loading of adopting a strategy that loads the spine symmetrically. 2. Methods A previously reported mathematical model of the lumbar spine and its musculature [1,2] was used as the basis for this study. The model represented six motion segments of the lumbar spine (T12-L1 through L5-S1), and the muscles that cross these levels. The thoracic spine was not included, in order to avoid additional variables associated with the ribs. The skeletal and muscular geometry, and motion segments represented as beam elements, was based on that reported in Stokes and Gardner-Morse [1,2]. The initial spinal geometry (with sagittal plane curvature, but no scoliosis) was then transformed in order to produce five idealized scoliosis curves with increasing scoliosis magnitudes of 13, 26, 38 and 51 degrees Cobb angle, apex at L-2, as was done by Stokes [3]. For each deformed spine shape, the muscle end points were repositioned according to displacements and rotations of their associated vertebral attachment sites.

Figure 1: Model geometry (vertebrae and lines of action of muscles) for the model that represented a lumbar scoliosis magnitude of 38 degrees Cobb, apex at L-2. The modeling problem of determining the muscle forces associated with any given external load is statically indeterminate, since the number of muscles crossing the lumbar spine exceeds the number of intervertebral degrees of freedom. Four muscle activation strategies were analyzed. In Strategy 1, the indeterminate problem was solved for the unique case of maximum external efforts. These were calculated for the 58 degrees Cobb scoliosis geometry, and for positive and negative external moments generated about each

/. Stokes and M. Gardner-Morse / The Role of Muscles and Effects of Load on Growth

of the global axis directions (flexion, extension, left and right lateral bending, clockwise and counter-clockwise axial rotation) in turn. Then simulations were performed for two loading states: 50% and 75% of the maximum efforts calculated previously. For the submaximal efforts, each muscle activation strategy was defined by an objective function in a non-linear optimization. At each level of effort (50% and 75% of maximum), simulations were performed for three different muscle activation strategies. In Strategy 2, the objective was to minimize the sum of squares of the muscle stresses, as proposed by Hughes et al. [4]. In Strategy 3, the objective was to minimize the sum of the squares of the lateral bending moments at all motion segments of the lumbar spine, in addition to minimizing the sum of squares of the muscle stresses. Then, if the moment objective is met, the loading distribution across the vertebrae can be considered to be uniform (the 'follower load' as described by Patwardhan et al. [5]). In Strategy 4, the objective was to maximize the curve correcting moment at the two motion segments adjacent to the curve apex (L-2). As in Stokes et al. [1], bounds were placed on muscle forces and intervertebral displacements according to physiologically plausible limiting values. 3. Results Strategy 1 predicted maximum external effort moments of 56 and 66 Nm (flexion and extension), 72 Nm lateral bending, and 20 Nm axial rotation at the 51 ° Cobb curve magnitude. At 50% and 75% of these moments, the Strategy 2 simulations (minimize muscle stresses) predicted spinal loading that was offset up to 12 mm at the L2-3 level (apex). This loading is compatible with growth modulation that would increase the scoliosis according to the 'vicious cycle' theory. Strategy 3 (minimize lateral bending moments) predicted zero intervertebral lateral bending moments in all cases ('follower load'). However, the muscle recruitment pattern that achieved this 'follower load' state required greater muscle stresses (Figure 2), and correspondingly greater intervertebral compression force magnitudes. In Strategy 4, a correcting moment was achieved under all simulated conditions at the apex, and this was associated with asymmetrical loading of the vertebrae that would reverse the 'vicious cycle'. However, to achieve this, the mean muscle stresses and associated spinal forces were increased relative to Strategy 2 values by about twice as much as for Strategy 3.

i Figure 2: The increase in mean muscle stress that was required to achieve a 'follower' loading of the spine (Strategy 3), relative to that for Strategy 2 (minimize muscle stress only). MX is lateral bending moment, My is flexion/extension, and Mz is axial rotation moment.

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4. Discussion A muscle activation strategy that minimized the lateral bending moments was able to reduce these moments to zero, thereby creating a loading state that would produce no scoliosis progression according to the 'vicious cycle' theory. This loading condition is similar to the 'follower load' [5] where the load takes the same path relative to the vertebrae as the spine deforms. Thus the follower loading imposes minimal or zero moments about the spinal motion segments. Furthermore, it was possible to simulate a muscle activation strategy (Strategy 4) that would produce a correction moment and a loading asymmetry compatible with reversing the presumed 'vicious cycle' mechanism of curve progression. One can speculate that different individuals with scoliosis adopt differing muscle activation strategies, and that some strategies predispose to a spinal loading state that produces substantial progression during growth, while others do not. This paper demonstrates that there are multiple plausible loading states, resulting in a wide range of lateral bending moments in the motion segments; hence differing degrees of asymmetrical loading of the vertebrae and discs. Some loading conditions might cause scoliosis progression, while others would not. References: 1

2 3 4 5

Stokes and Gardner-Morse. Lumbar spine maximum efforts and muscle recruitment patterns predicted by a model with multijoint muscles and joints with stiffness. Journal of Biomechanics 1995; 28(2): 173-186. Stokes IAF, Gardner-Morse M: Quantitative anatomy of the lumbar musculature. Journal of Biomechanics 1999, 32: 311 -316. Stokes IAF: Analysis of symmetry of vertebral body loading consequent to lateral spinal curvature. Spine 1997; 22(21): 2495-2503. Hughes RE, Chaffin DB, Lavender SA, Andersson GB. Evaluation of muscle force prediction models of the lumbar trunk using surface electromyography. Journal of Orthopaedic Research 1994; 12(5):689-98. Patwardhan AG, Havey RM, Meade KP, Lee B, Dunlap B. A follower load increases the load-carrying capacity of the lumbar spine in compression. Spine, 1999; 24(10): 1003-1009.

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Achondroplasia: 3D - CT Evaluation of the cervical spine I. Tsitouridis, D. Melidis, M. losifidis, A. Morichovitou, F. Goutsaridou, S. Stratilati, G. Giataganas, Ch. Papastergiou.

Radiology Dept, Papageorgiou General Hospital, Thessaloniki, Greece.

The purpose of our study is to present our experience from the evaluation with 3D - CT, 9 patients with spinal achondroplasia. Achondroplasia is the most common form of congenital dwarfism and spinal manifestation is the deformity of the spine due to the achondroplastic configuration of vertebral bodies. The examinations were performed with a spiral CT scanner picker PQ 5000, a Picker Voxel Q visualization workstation. The original axial CT scans were reconstructed in 3D models with MPR, SSD and VR techniques. All the 9 patients revealed small spinal canal, occipitalization of Cl, Cl was hypoplastic in 7 cases and odontoid process was shorter than normal in 5 cases. In one patients there was a C2 - C3 sublutation. 3D - CT reconstractions clearly revealed the whole cervical spine in different angles, which help us to understand clearly the previous reported abnormal findings. In conclusion 3D - CT evaluation of the achondroplastic patients is the method of choice in the detection and characterization of the lesions. Achondroplasia is a rhizomelic short - limbed dwarfism with genetically determined derangements of cartilaginous growth. It is an autosomal dominant disease with a very high mutation rate, so 80% of all cases actually appear as spontaneous mutation in normal families. Males and females are affected equally. Spinal neurologic symptoms, observed in 40 - 50% of patients, result from compression of normal neural structures within an abnormally narrow, ligamentously unstable spinal canal. Clinically, the neurological presentation falls into four major groups (1) progressive insidious onset of increasingly severe paresthesias, sciatic pain and back pain followed by inability to walk and urinary incontinence (2) intermittent claudication with intermittent pain or paresthesia (3) nerve compression signs and (4) acute onset of severe back or leg pain. The ossification centers in cartilage are obnormally small. Insufficient longitudinal growth of enchondral bone reduces the height of the vertebral bodies to one - third normal size. The abnormally large achondromplastic head increases vertical loading on the spine. Thoracolumbar kyphosis is common. The enchondral skull base is small, although the overall head size is increased. The foramen magnum is extremely small and seems to be displaced anteriorly. Basilar impression is present in 37 - 50% of cases. The petrous pyramids may be elevated asymmetrically and the paranasal sinuses are unusually prominent. In our study, we examined 9 patients with achondroplasia. We pointed our interest in cervical spinal anomalies. All the 9 patients had reduced height, (with an average height of 1,2m for males and 1m for females) and had small spinal canal. Occipitalization of Cl revealed in all patients. In 7 cases Cl was hypoplastic and in 5 cases the odontoid process was shorter than normal. Finally in 1 patient there was atlantoaxial subluxation.

All 9 patients were performed with plain radiographs and axial CT scans of the cervical spine. Then we proceed in 3D reconstruction of the original CT scans with MPR, SSD and VR techniques. With the last methods we managed to pick up the previously reported anomalies in detail and to discover same of them not visible in plain scans.

References 1. T. H. Newton, D. G. Potts: Computed Tomography of the spine and spinal Cord, 1983

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Malformations of the craniocervical junction: 3D - CT Evaluation I. Tsitouridis F. Goutsaridou,, A. Morichovitou, G. Giataganas, M. losifidis, D. Melidis, S. Stratilati. Radiology Dept, Papageorgiou General Hospital, Thessaloniki, Greece.

The purpose of our study is to present our experience from the evaluation of the craniocervical junction malformations with 3D - CT. The examinations were performed with a spiral CT scanner picker PQ 5000, a Picker Voxel Q visualization workstation. The original axial CT scans were reconstructed in 3D models with MPR, SSD and VR techniques. In the group of the patients of our study, included 13 patients with malformations of the arches of Cl and C2, 3 with atlantoaxial fusion and irregular segmentation, 5 with fusion of C2 and C3 and the rest with dens malformations. 3D - CT examination clearly picked up the lesions in detail, although some of them also detected with plain radiographs. In conclusion, we believe that 3D - CT is the method of choice in the detection and characterization of the malformations of the craniocervical junction. The malformations of the foramen magnum and upper cervical spine include occipital and suboccipital dysplasia. Occipital dysplasia signifies primary malformation of the occipital bone and includes manifestations of occipital vertebrae, congenital basilar impression, condylar hypoplasia and assimilation of Cl to the occiput. Suboccipital dysplasia signifies primary malformations of Cl and of C2. Those of Cl include aplasia of the arch of Cl, clefts in the arch of Cl, atlantoaxial fusions and irregular segmentation of Cl and C2. Those of C2 ovelap with those of Cl and include atlantoaxial fusions, irregular segmentation of C1 and C2, persistent as terminate and os odontoideum, dens dysplasia, hypoplasia and aplasia, spina bifida of C2 and fusion of C2 with C3. Patients with cervical segmentation anomalies frequently manifest a short or asymmetrical neck or fixed - head position (65%), unilateral high scapula (41%), kyphosis or scoliosis (28%) and miscellaneous other anomalies. Symptoms consist mainly of pain in the occiput and neck, vertigo, unsteady gait, paresis of the limbs and varied cerebellar, medullary and cervical root signs. Symptoms often begin late in life and progress slqwly. In our study, we examined 25 patients with malformations of the craniocervical junction. Of our patients. 13 had malformations of the arches of Cl and C2. There was no complete absence of the anterior or posterior arch of Cl, which is rare. Partial aplasia is more frequent. 3 patients had partial aplasia of the posterior arch of C1: one had aplasia with persisting posterior tubercle, 1 hemiaplasia, 1 partial aplasia of one half an arch. In 1 patient, partial aplasia of the posterior arch of Cl combined with hypertrophy of the dens. The rest 10 patients had clefts within the arches of the atlas, 2 of them anterior and 8 posterior. The posterior clefts were all median. We had no clefts in the arches of axis. 3 of our patients had atlantoaxial fusion and irregular segmentation. In 1 patient we found irregular fusion of the lateral masses of C2 with the arches of Cl. The result was asymmetrical vertebrae with displaced intervertebral joints. The other 2 patients had partial

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fusion of Cl and C2 with in the level of anterior arch of Cl with dens the first and in the level of right hemiarches the second. 5 patients had fusion C2 and C3. 2 of them presented with complete fusion (klippel - Fleil syndrome) and 3 with fusion of the posterior elements only. The last 4 patients had dens malformations. 2 of them with moderate hypoplasia, 1 with hypoplasia with persistent os terminale and 1 with advanced hypoplasia with os odontoideum. All the 25 patients were performed with plain radiographs and then with CT scans of the craniocervical junction. In almost all cases we recognized some of the malformations in plain radiographs and nearly all of then in CT scans. Then we proceed in 3D reconstruction of the original axial CT scans with MPR, SSD and VR techniques. With this method we managed to pick up the lesions in detail and to find out some lesions which were not obvious in the plain CT scans. References 1. T. H. Newton, D. G. Potts: Computed Tomography of the Spine and Spinal Cord, 1983 2. Wackenbeim A: Roentgen Diagnosis of the Craniovertebral Region. New York: Springer - Verlag, 1974 3. Wickbom I, Hopafee W: Soft tissue masses immediately below the foramen magnum. Acta Radiol. 1: 647 - 658, 1963.

Th.B Gnva.M Research into Spinal Deformitie I OS fV [121

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G.P. Spanos / Sciatic Scolinsis

7. Results 40 patients with a deformity of more than 5 m.m. with LBP of less than 12 weeks duration entered the study. 18 of them had lower leg pain in a root distribution. 12 had SLR less than 50°. The deformity had resolved in the 64% of the Mckenzie patients by 28 days compared with 50% of the control group. There was a significantly greater resolution (89% compared with 50% of the control group, p=0,04) after 90 days. Other studies resulted at similar figures of resolution but much more quicker, actually within the first week.npl As a matter of fact, data collected from the R. Mckenzie's studies results in a resolution of 93,6% of the population, m these studies 470 patients out of 526 were symptoms free much more quicker, that is in the first week, with full reduction of the deformity. Additionally, the majority of them had great improvement after 24 to 48 hours. In this group the 33% had referred pain in the lower leg and 75% neurological insuficiency. Further, 24 patients out of 526[11 had some delay in their progress. As a matter of fact 18 of them were symptoms free in the first week but some deformity remained, which was corrected the second week. Three patients needed 3 weeks and for the other three remaining it took a month for full correction of the deformity and abolition of the syndromes. Finally, 32 patients out of 526 failed in the management. Twenty seven of them had symptoms of more than 12 weeks duration, 3 of them had symptoms for 8 weeks and 2 had symptoms for 3 and 5 weeks respectively.'11 8. The Mckenzie treatment The Mckenzie treatment follows the principles of the derangement syndrome management. Especially the one for the derangement number 4 or 6. The steps for this treatment are: a. correction of the deformity (figures 2,3,4,5) b. reduction of the derangement c. maintenance of reduction d. restoration of function and e. prophylaxis.1'1121161

Figure 2

Figure 3

Figure 4

Manual convenor! of (he deformitv h\ the Mcken/ie method

Figure 5

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9. Conclusions - Discussion The Gillan et al study suggests that Mckenzie management may well be an improvement of the natural history of the sciatic scoliosis as 50% of the controlled group had it at 90 days and only 11% of the Mckenzie group.[8] Further, if we consider the figures of the R. Mckenzie's study [11[2] had better results regarding effectiveness, time of treatment and disability, the whole procedure of the Mckenzie method certainly warrants further investigations. In that case, more attention should be paid on the correct application of the principles of Mckenzie method, such as: 1. Treatment should be applied on a daily basis, not twice a week or less. 2. Patient's self correction of deformity and education is of paramount importance. 3. Restoration of lordosis and prophylaxis should be achieved, too. References 1. 2. 3. 4. 5. 6.

7. 8. 9. 10. 11. 12.

R. A. Mckenzie "Manual Correction of Sciatic Scoliosis, NZ Med. Journal 484, 76:194-199, 1972. R.A. Mckenzie "The Lumbar Spine Mechanical Diagnosis and Therapy". ISBN 047300644 Spinal Publications, New Zealand, 1981. RW Porter, CG Miller. "Back Pain and Trunk List". Spine 11:596-600, 1986. J. Kramer. "Intervertebral Disk Diseases, ISBN 3-13-582 402-0. Georg Thieme Verlag, Stuttgart - New York, 1990. PW Porter. "Pathology and Multifactorial Aspects of Symptomatic Disc Protrusion, 3rd Mckenzie Institute International Conference, Torondo, Canada, 1993. R Donelson, C Aprill, R Medcalf, W Grant. "A Prospective Study of Centralization of Lumbar and Referred Pain. A Predictor of Symptomatic Discs and Annular Competence". Spine, 22, 10:1115-1122, 1997. B Khuffash, RW Porter. "Cross Leg Pain and Trunk List" Spine, 14:602-603, 1989. MG Gillan, JC Ross, IP Mcklean, RW Porter. "The Natural History of Trunk List, Its Associated Disability and the Influence of Mckenzie Management". Eur Spine Journal, 7(6) :480-3, 1998. IP Mclean, MG Gillan, JC Ross, RM Aspden, RW Porter. "A Comparison of Methods for Measuring Trunk List". Spine, 21:1667-1670, 1996. S Kilpikoski et al. "Interexaminer Reliability of Low Back Pain Assessment Using the Mckenzie Method". Spine, 27:E 207-E 214,2002. H Rajmjou, JF Kramer, R Yamada. "Intertester reliability of the Mckeknzie Evaluation in Assessing Patients with Mechanical Low Back Pain" J Orthop & Sports Phys Ther, Jul;30(7):368-383,2000. MS Donahue, Riddle DL, Salivan MS. "Intertester Reliability of a Modified Version of the Mckenzie's Lateral Shift Assessments obtained on patients with L.B.P." Phys Ther 1996;76:706-716

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Pathomechanic basics of conservative treatment of progressive idiopathic scoliosis according to Dobosiewicz method based upon radiologic evaluation Krystyna Dobosiewicz, Jacek Durmala, Krzysztof Czernicki, Hanna Jendrzejek Department of Rehabilitation, Medical University of Silesia, Katowice, Poland 40-635 Katowice, ul. Ziolowa 35/37, POLAND e-mail rehabilitacjasam @poczta. onet.pl Abstract Conservative treatment of idiopathic scoliosis, especially kinesitherapy, is not widely appreciated due to its suspected low effectiveness in relation to a surgical treatment. After long-year assessment of patomechanics of scoliosis in Department of Rehabilitation of Medical University of Silesia a conservative method of treatment, asymmetric trunk mobilization in strictly symmetric positions, was developed. This method enables to detain progression of scoliosis, or even decrease lateral curvature of a spine and angle of rotation assuming adequate cooperation of patient and its family.

1. Introduction Idiopathic scoliosis (IS) is a three-dimensional deformation of a vertebral column and entire trunk. After many years of extensive researches the cause of idiopathic scoliosis still remains unknown. It is possible that idiopathic scoliosis develops and progress on a basis of multifactor disorder, perhaps different for curve initiation and curve progression. From possible pathologic factors nervous system dysfunctions affecting postural equilibrium and proprioceptive control seem to be especially important. [1,2, 6, 3] Progression of IS could be determined by vertebrae remodeling under eccentric loading created by axially acted gravitational forces in presence of muscular imbalance in the trunk. [2] The vertebral column under scoliotic conditions is an unstable system with tendency to further curve development. [12] Lateral bending of a vertebral column, visible in X-ray examination, is only a two-dimensional presentation of a complex deformity, consisting of pathological axial rotation, torsion and other deformations of vertebrae. [7, 8, 10, 11, 14] In IS physiologic curvatures of vertebral column are disturbed. Total length of an anterior column of a spine, consisting of vertebral bodies and intervertebral discs, becomes greater than length of a posterior column - vertebral arches and processes. [11, 15] It is apparent that physiological thoracic kyphosis in region of a scoliotic curve diminishes. Each vertebra of a structural curve of scoliosis is orientated in hyperextension in relation to adjacent vertebrae, [7, 11] resulting

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K. Dobosiewicz et al. / P athome chanic Basics of Conservative Treatment

Fig. I .

Symmetric t

Symmetric exercise positions (1-5) and intermediate position (I). Derotation forces during asymmetric mobilisation of a trunk.

in decreased kyphosis or even true lordosis in an affected region. Axial rotation in hyperextended region produces picture of lateral curvature, described as rotation lordosis. [10, 13] The two factors, overextension and rotation, reflex lateral curvature development, eventually aggravated by positive feedback of eccentric load in condition of muscular instability .

2. Kinesitherapeuthic method of treatment according to Dobosiewicz: trunk mobilization in strictly symmetric positions

asymmetric

Main assumption of kinesitherapeuthic method developed by Dobosiewicz is creation of thoracic kyphosis and derotation of vertebrae with simultaneous dilation of intercostal and paravertebral spaces on the concave side of scoliosis. Basic foundations of method of asymmetric trunk mobilisation in strictly symmetric positions depend on type of scoliosis, value of thoracic kyphosis and asymmetry of pelvis position. [6, 4, 5] Following conditions should be met to attain demanded effect: - Initial exercise positions should be maximally kyphotic and strictly symmetric to allow adequate extend of asymmetric movement of a trunk (Fig. 1). Most initial positions exclude action of erector spinae and psoas major muscles and axial gravity load on vertebral column. Stabilisation is provided by superficial muscles of chest and back, mostly pectoralis major and minor, anterior serrate, trapezius, rhomboidei and latissimus dorsi.

K. Dolwsiewic- el nl. / Pathomechanic Ruxica of Conservative Treatment

- Asymmetric movement of a trunk is conducted accommodating intercostal muscles and a diaphragm. Asymmetric contraction of intercostal muscles in the concave area in symmetric position causes physiological 'buckle handle' movement of ribs. This kind of movement elevation and rotation in costo-vertebral joints - effects in dilation of intercostal and paravertebral spaces and derotation of vertebrae (Fig. 2). Eventually lateral curvature of vertebral column also decreases. - Muscles of anterior abdominal wall serve for movement control and correction of pelvic rotation and inclination. Oblique muscles mainly correct axial pelvic rotation and additionally stabilise initial position. Rectus abdominis muscle rotating pelvis around a transverse axis (decreasing angle of inclination) causes additional elongation of a thoracic and lumbar segment. Elongation primarily concerns with posterior columns of a spine, producing further correction of a scoliosis. 3. Material 208 children (21 boys and 187 girls aged 6-19, mean 13.8 M and 14.3 F) suffering from idiopathic scoliosis has been treated since November 1999 till September 2001 in Department of Rehabilitation of Medical University of Silesia. 114 of them presented single scoliosis and 94 double-major scoliosis. In single scoliosis mean Cobb angle was 11 - 55° (mean 33.2_ ± 17.1_), angle of axial rotation 3 - 20 ° (mean 9.4 ° ± 6.1_). In double major scoliosis Cobb angle in thoracic region was 12 - 66 ° (mean 34,2_ ± 15.1_), angle of axial rotation 3 - 30 ° (mean 12.6 ° ± 8.9_). In lumbar region of double major scoliosis Cobb angle was 20 - 59 ° (mean 35.3_ ± 12.4J and angle of axial rotation 4 - 30 ° (mean 17.8 ° ± 10.2J.

K. Dobosiewicz el al. / Pathomechanic Basics of Conservative Treatment

4.

339

Method of treatment

X-ray evaluation of scoliosis was carried out in standardised technical conditions at least twice in periods of at least 6 months. Cobb angle and angle of axial rotation of an apical vertebra according to Pedriolle technique were measured always by the same physician.

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K. Dohosicwic: et ni / Ptithinneclutnic Hastes of Conservative Treatment

5. Results Results of treatment obtained on the basis of X-ray evaluation of progression of a scoliosis (Fig. 3) are shown in Table 1. Method of asymmetric trunk mobilization in strictly symmetric positions is especially valuable in treatment of single structural curves of IS. Results in double major scoliosis are less promising, but still worth considering. Proposed method was applied mostly in children in age of puberty and related adolescent growth 'spurt'. Natural history of scoliosis progression shows usually dramatic scoliotic curve worsening related to this period of life. [9] This opportunity furthermore advocates proposed method of treatment. 6. Conclusions Table 1. Results of Dobosiewicz method of conservative treatment of idiopathic scoliosis. single scoliosis Cobb angle rotation angle

regression progression regression progression

33.6% 33.6% 21.6% 19.8%

Double major scoliosis thoracic region 22.8% 28.3% 16.3% 25.0%

lumbar region 26.1% 28.3% 16.3% 30.4%

1. Method of asymmetric trunk mobilization in strictly symmetric positions in most cases results at least in detention of a scoliosis progression. Proposed method should be then considered in scoliosis treatment as a single method of treatment or as an element of rehabilitation before planned surgery. 2. In conservative method of treatment biomechanical function of a vertebral column remains preserved and benefits in further quality of life of patients. References 1. 2. 3. 4.

5.

Abbott Byrd J.: Current theories on the etiology of idiopathic scoliosis. Ciin Orthop. 229,1988,114-119. Burwell R. G.: The aetiology and pathogenesis of adolescent idiopathic scoliosis (AIS). Eur. Spin. Resonances 1994, 3-6. Dobosiewicz K., Czernicki K., Dyner-Jama I.: Mono- and polysynaptic reflexes in aetiology of idiopathic scoliosis. European Spine Journal, 1999,8 (Suppl. 1), 34. Dobosiewicz K., Durmala J., Dyner-Jama I. et al.: Evaluation of the conservative treatment (asymmetric mobilisation of the trunk in strictly symmetric positions) of idiopathic progressive scoliosis by radiological and exercise efficiency testing. European Spine Journal 2001,10 (Suppl. 1), 58. Dobosiewicz K., Durmala J., Kotwicki T. et al.: Wp_yw asymetrycznej mobilizacji tu_owia na zachowanie si_ k_ta Cobba i rotacji w przypadkach bocznych idiopatycznych skrzywie_ kr_gos_upa u dzieci i m_odzie_y. Post_py Rehabilitacji, 2001, XV(3), 21-22.

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6. 7. 8. 9.

10. 11. 12. 13. 14. 15.

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Dobosiewicz K.: Boczne idiopatyczne skrzywienia kr_gos_upa. Slaska Akademia Medyczna, Katowice 1997. Dubousset J, Herring J. A., Shufflebarger H.: The crankshaft phenomenon. J. Pediatr. Orthop., 1989, 5, 541-550. Dubousset J.: Three-dimensional analysis of the scoliotic deformity. In: Weinstein S. L. (ed.): The pediatric spine, Raven Press, New York, 1994,479-496. Duval-Beaupere G.: Pathogenic relationship between scoliosis and growth. In: Ph. Zorab (ed.): Scoliosis and growth. Proceedings of a 3rd symposium held at the Institute of Diseases of the Chest, Brompton Hospital, London, 13 Nov 1970. Churchill Livingstone, 1970, pp. 57-63. Pedriolle R.: La scoliose. Son etude tridimensionelle. Maloine S. A. (ed.), Paris, 1979. Roaf R.: The basic anatomy of scoliosis. J. Bone Joint Surg., 1966,48-B, 786-792. Smith T. J., Fernie G. R.: Functional biomechanics of the spine. Spine 16 (10), 1991,1197-1203. Sommerville E. W.: Rotation lordosis: the development of the single curve. J. Bone Joint Surg., 1952, 34-B, 421-427. Tylman D.: Patomechanika bocznych skrzywie_ kr_gos_upa. Severus, Warszawa, 1995. Winter R. B., Lovell W. W., Moe J. H.: Excessive thoracic lordosis and loss of pulmonary function in patients with idiopathic scoliosis. J. Bone Joint Surg., 1975, 57-A. 972-977.

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Conservative management in patients with scoliosis - does it reduce the incidence of surgery? Hans-Rudolf Weiss, Grita Weiss, Hans Jiirgen Schaar Asklepios Katharina-Schroth-Klinik, Korczakstr. 2, D-55566 Bad Sobernheim Abstract The effectiveness of conservative scoliosis treatment, including bracing, is widely denied. Like any therapeutic intervention, conservative scoliosis treatment including patient education, techniques of brace moulding, and time-consuming follow-ups is reasonable only if the benefits outweigh the strain placed upon the patient by the treatment. The most important benefit of early intervention in scoliosis is prevention of the need for spinal fusion surgery. Retrospective analysis of the incidence of surgery for patients with scoliosis, by comparison with incidence in an untreated control group. Since 1992 the bracing technique according to Cheneau has been applied in parallel with the scoliosis inpatient intensive rehabilitation programme (SIR). For this study we chose from our data base the scoliosis patients who had conservative treatment at our center between 1993 and 1996. All patients, like those of the control group, were at least 15 years of age at the time they were evaluated for the last time. The incidence of surgery of our group was compared with that reported by a center in Ireland. Of 343 female scoliosis patients with a curve angle of 33.4^€ (SD=18.9), 41 (11.95%) had surgery. The incidence of surgery of our collective was significantly lower than the incidence of surgery of the control group which reported an incidence of 28,1%. The AIS matched group of patients (n = 179) had an incidence of surgery of slightly more than 7%. When compared with a matched control group of untreated patients, incidence of surgery was significantly reduced by SIR combined with bracing. So conservative management is indicated in patients with scoliosis.

1. Introduction On the one hand the literature confirms the effectiveness of certain orthoses in the treatment of scoliosis [1, 2], and yet on the other hand their effectiveness is generally denied and the treatment is widely rejected [3, 4]. Although conservative methods of treatment with physiotherapy and braces are generally accepted in central Europe as special branches [5, 6], conservative treatment in the USA is largely discounted. In addition to the language barrier, which is so prejudicial to the English-speaking countries in that it reduces the availability there of up-to-date information about conservative methods of treatment of scoliosis, a number of mistaken and unhelpful ideas even exist in the practice of this treatment which, far from being beneficial to patients, may actually put strain on them [7]. In Germany conservative treatment is regarded as effective if a curvature shows no further progression (even when further growth is expected) or if there is a clear tendency towards a decreasing curvature. Hanks et al. [7] nevertheless speak of successful brace treatments in the USA, providing the increase of the curvature is no greater than IQJE. Based on our own review of the literature we were able to prove that there does indeed

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exist a direct positive correlation between the primary effect of an orthosis and the end result [8]. In his study of the treatment of idiopathic scoliosis with the aid of the ChSneau brace, Landauer [2] also concludes that compliance on one hand and the primary effect of the brace on the other, are the main parameters of successful brace treatment. In the USA however braces are not very often "custom-made". They are able to achieve a corrective effect of 50% in relation to the initial curvature, but only on smaller curves, and thus may indeed exercise an essential influence on the final prognosis [9]. This shows that the question of the effectiveness or not of conservative treatment in general and of scolioses orthoses in particular is very complex and cannot be answered on a onedimensional basis. By contrast the treatment of scoliosis with the Cheneau brace is currently most practised here in Germany [10] .The clinical histories of individuals enjoying excellent corrective effects and favourable outcomes are encouraging the use of this method here. We must emphasise nevertheless that however well-adjusted an orthosis may be, there do indeed exist curvatures whose progression cannot be halted. And so we ask the following questions: are our efforts reasonable and worthwhile - involving as they do the time-consuming education of patients, moulding techniques and follow-ups, and the strain put on patients by all the conservative methods? Or should we follow the American way of scoliosis treatment? - that is to say, "Wait until the scoliosis has to be corrected surgically!" In a recent study Goldberg and her collaborators [4] analysed the incidence of surgery in patients with adolescent idiopathic scoliosis at several centres in which a comparison between the incidence of surgery in braced patients and the incidence of surgery in non-braced patients was made. The authors concluded in their study that as far as the number of surgical interventions was concerned, from a statistical point of view, patients who used a Milwaukee brace in the years between 1950 and 1970 did not differ from untreated patients in the 90's. Although the methodology of this study showed some weaknesses [6] it has enabled us to use the collective of Goldberg et al. [4] as a control group for a retrospective study of our own. When offered unbiased information, many patients, even those with curvatures of over 40M, nevertheless opt for conservative treatment. And so in order to be able to explain to patients whether surgery is a reasonable procedure or not, we thought it would be useful to make a study of the effectiveness (or not) of conservative scoliosis management including outpatient physiotherapy, inpatient intensive scoliosis rehabilitation and brace treatment.

2. Material and method In order to answer the question as to whether conservative methods (outpatient physiotherapy, inpatient intensive rehabilitation (SIR) and brace treatment - in this case mainly the Cheneau brace - are effective, we have compared the incidence of surgery in patients presenting various kinds of aetiology treated conservatively at the our centre with the incidence of surgery reported by Goldberg et al. [4] in patients without conservative management. In the study by Goldberg and her collaborators [4] the criteria for inclusion were: 1. Diagnosis of adolescent idiopathic scoliosis 2. Minimum age of 15 years at last check-up (not younger than 10 years at first check-up) 3. Documentation for Cobb angle without brace at first check-up (at least 10°). Curve pattern distribution was given for the whole collective. In girls, menarchial status and the incidence of surgery were also known. In order to be able to compare the patients at our centre who had had one or more

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H.-R. VVV/.vv a al. /('onsen-alive Management in Patients with Sculiosix

inpatient intensive courses of rehabilitation (with or without brace) with the collective of Goldberg and her collaborators [4] we followed their study design. All patients (girls only in our study, aged between 10 and 13) diagnosed with scoliosis of every kind of aetiology and who had attended our centre between 1993 and 1996, were included in this study. As not all patients in this group had had repeated treatment at our centre or had had only outpatient appointments elsewhere, the study was conducted by means of a questionnaire. 689 patients were sent questionnaires by post.The number of responses was low - only 214 questionnaires were returned. We could not therefore present any convincing results with this group, and so all patients who failed to answer our questionnaire received a phone call and were subsequently sent the questionnaire for a second time. In this way we were able to reach 343 patients out of the described group. All others had moved away from their original addresses. The average angle of curvature according to Cobb before the first inpatient intensive course of rehabilitation was 33.4 ° (SD=18.9), which was comparable to the angle of curvature evaluated by Goldberg et al. (33 °) [4]. The distribution of the pattern of curvature was as follows: 1. Thoracic scolioses: 35% 2. Double major scolioses: 37.2% 3. Lumbar scolioses: 10.2% 4. Thoracolumbar scolioses: 17.2% 244 of the patients studied (71 %) wore braces. 235 of these also gave details of how long they wore their braces for. 58 patients (25%) wore the brace for up to 8 hours daily, 47 patients (20%) for up to 16 hours, 54 patients (23%) 16-21 hours, and 76 patients (32%) more than 21 hours daily. In surgically treated scoliosis patients (n=41) the angle of curvature according to Cobb was 50 ° (SD=25.4).

3. Results Patients treated with a programme of inpatient intensive scoliosis rehabilitation (SIR) showed an incidence of surgery of 11.95%; the patients in the Goldberg collective however showed an incidence of 28.1%. The differences are statistically highly significant. Out of the first 214 patients who sent back completed questionnaires, 11% had been treated surgically, whereas out of the 343 patients who were finally included in the study, 41 had had surgical treatment. There was no statistical difference between the incidence rate reported in the questionnaires returned initially and the incidence of surgery in the whole collective. A one-sided statistical test for the comparison of two independent proportions was used [11]. Using this method of testing highly significant differences with a test value of 3.995 at p< 0.0001 (a=0.05) were shown by reference to Goldberg's collective (no brace treatment, incidence of surgery 28.1%, n=153). Comparing this value with the Milwaukee-braced control group of Lonstein and Winter [12] (incidence of surgery 22.4%, n=1020) a highly significant difference was also evident (test value 4.7553, p< 0.0001 (a=0.05)). The differences by reference to the control group without brace treatment as studied by Noonan and co-workers [13] (surgery incidence 31%, n=88) reveal a similarly high significance. There was a probability of error of p=0.0001 with a test value of 3.6329).When comparing the diagnosis-matched patient groups (Adolescent idiopathic scoliosis Goldberg n =153, incidence of surgery 28.1% versus Weiss n = 179, incidence of surgery 7.3%) we found a test value of 5.05 with a probability of error of p5 degrees in angle of the most severe curvature was used to define 'progression.1 A onesided statistical test to compare two independent proportions was used to test the hypothesis that the proportion of patients with progression differed between the two study groups [19]. 3. Results Group I (5 degrees. Even though more severe curvatures (range 6-52 degrees) were included in the SIR Group I, the incidence of progression in the SIR test group was only 46.66%, and was statistically distinct at the 0.011 level of probability (Table 1). Within the SIR test subgroup la, whose range of curvatures was closely matched with that of the control group, only 40.0% of the cases progressed. The difference was statistically significant at the 0.0029 level of probability.

Table 1. Progression in matching subset of treated and control groups Source (a) Weiss I*

n** Ila***

Total

Aee

Curve

FoUowuo

Procression

30 59 26

10±P.85 13±0.71 13.6+0.5

21±10.7 29.5±14.3 42.3+10.9

35±23 34±37 36+34.1

14/30 (46.7%) 18/59(30.5%) 5/29 (19.2%)

64 43

12-cm difference between circumference of the left and right sides of the ribcage (Figure 2). By the end of treatment, the difference was less than 1 cm.

Figure 2. Relationship between improved chest expansion (solid line) and improved torso deformity (broken line). 'Chest expansion was measured directly based on the difference in total chest circumference at minimum and maximum inhalation [5]; 'torso deformity* reflects left-right torso asymmetry, measured directly based on the difference between left and right ribcage from anterior and posterior midiine. Each value represents mean and standard deviation from at least 30 measurements taken over a 48-h period.

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Af C. Hawcs und W.J. Rrooks / Reversal t>t the Sign* and Svinpronis

5. Discussion Improved signs and symptoms in longstanding, previously untreated idiopathic scoliosis occurred in response to a combination of mobilization therapies applied daily over a sustained period. The forty-percent improvement in magnitude of Cobb angle achieved in this study is in the thirty- to forty-percent range of improvement that can be obtained using spinal fusion surgery in adult scoliosis [6]. The change in curvature was correlated with a 7.5-cm increase in chest expansion, a > 10-cm reduction in torso asymmetry, and a near-elimination of pain and respiratory symptoms [5]. The fastest rate of change occurred during 1992-1995, and 1999-2000, two periods when the patient was treated with CMM. During thefirst period a range of therapies including psychotherapy, massage therapy, CMM and daily self-therapy were employed. From 1995-1999 only daily self-therapy was used. From 1999-2000 seven sessions of CMM were used in addition to daily self-therapy. The results are consistent with the possibility that CMM significantly influenced outcome when mobilization therapies were used to treat signs and symptoms of longstanding thoracic spinal deformity. References 1.

2. 3. 4. 5. 6.

7.

Bowen, R. M. 1995 Respiratory Management in Scoliosis. In Lonstein J, Bradford D, Winter R, Ogilvie J (Eds.) Moe's Textbook of Scoliosis and Other Spinal Deformities, 3rd Edition, WB Saunders, Philadelphia: 1995, pp572-580. Szeinberg, A., Canny, C.J., Rashed, N., Veneruso, G., and Levison, H. Forced VC and maximal respiratory pressures in patients with mild and moderate scoliosis. PedPu/mo,? 4: 8-12.1988. Chong, K.C., Letts, R. M., and Gumming, C. R. Influence of spinal curvature on exercise capacity. JPe'l Orthop 1: 251-254.1981 Myers, J., Prakash, M., Froelicher, V., Dat, D., Partington, S., Atwood, J.E. Exercise capacity and mortality among men referred for exercise testing. NEngUAfed346: 793-801.2002. Hawes, M.C. and Brooks, W.J. Improved chest expansion in IS after intensive, multiple modality, non surgical treatment in an adult Chest 120: 672-674. 2001. Bradford, D. S. Adult Scoliosis, In Lonstein J, Bradford D, Winter R, Ogilvie J (Eds.) Moe's Textbook of Scoliosis and Other Spinal Deformities, 3rd Edition, W.B. Saunders, Philadelphia: 1995,369-386. Kappler, R. E., Jones, J.M., and Kuchera, W.A. Diagnosis and Plan for Manual Treatment - A Prescription. In Ward, R.C. (Ed.). Foundations for Osteopathic Medicine. Williams and Wilkins, Baltimore: 1997, 483-488.

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Long-term effects of scoliosis Marc Asher, Douglas Burton Kansas University Medical Center, Kansas City, Kansas USA The focus of this presentation is adolescent idiopathic scoliosis (AIS), which is by far the most common scoliosis. It is a lifetime, incurable, and usually mild condition of unknown cause or, more likely, causes. Its natural history is generally favorable in comparison to the general population. Mortality is not increased in comparison to the non-scoliotic control population.2'3'15'18 Mortality is increased for patients with scoliosis onset during their juvenile years.15 Risk of mortality appears to be limited to patients with thoracic curves whose vital capacity is less than 45% predicted and scoliosis greater than 110° by age 15.14 Shortness of breath symptomatology occurs not only in patients with thoracic but also those with double and even occasionally with thoracolumbar curves. Severe shortness of breath does not appear in patients with curves of less than 80° and vital capacity of more than 70% predicted.18 Acute and chronic back pain is increased in comparison with the control population. However, pain does not correlate with curve pattern, curve magnitude, or the presence of osteoarthritic changes.19 Pain management does not appear to be a problem except in occasional patients who have been operated.11 Work and social histories are generally similar.9 These findings have been confirmed in a recent study in which neither work nor activity levels were different between the control group and the scoliotic group of patients at an average age of 66 years and follow-up of 44 to 61 years.19 Fortunately, most curves are small enough (less than 30°) that treatment is never needed. For patients with larger curves the treatment is conceptually unsatisfactory. Bracing is poorly tolerated and its effectiveness debated.7'12'13'16 Surgery involves the trade-off of a stiff and less curved spine for a stable and curved spine. In addition, a patient's risk of subsequent surgery is 6% to 32% at a minimum follow-up of 5 to 12 years.4'5'6'10 The lifetime risk is unknown. Primary surgery in adults is infrequently indicated. In the Iowa series it would appear to be about 8 in 203 or 4%.19 Primary degenerative spondylosis is an important and little understood co-morbidity. Subsequent surgeries following primary deformity surgery in adulthood are necessary in at least 15% of patients at a minimum follow-up of 2 to 3 years.7'17 The lifetime risk is, again, unknown. When indicated, there are several advantages for surgery during adolescence. Among the reasons are a less fixed trunk deformity, better capacity for secondary curves to compensate, and achievement of anterior column load sharing through residual growth. However, there are a number of disadvantages, including the generally kind natural history of the condition, the fact that few adults present with symptoms severe enough to warrant surgery, and the reality that a patient's co-morbidities have yet to appear.

In conclusion, when managing patients with adolescent idiopathic scoliosis, it is important to remember that it is not a fatal condition. In addition, most curves are so small that they do not require any treatment. Selection of treatment requires considerable judgment as the generally accepted treatment options have substantial shortcomings. It is becoming increasingly clear that curve size alone is not the only important factor in selecting treatment.1 Acknowledgments The authors wish to thank Terry Orrick, academic secretary, and Barbara Funk, editor, for their assistance in the preparation of this manuscript. This study was supported in part by the Scoliosis Research Fund, Kansas University Surgical Association. CONFLICT OF INTEREST DISCLOSURE: See Asher et al: Trunk deformity correction stability... This volume. References 1.

2. 3. 4.

5.

6. 7. 8.

9. 10.

11. 12.

Asher, M.A.; Lai, S.M.; Burton, D.; and Manna, B.: Discrimination Validity of the Scoliosis Research Society-22 Patient Questionnaire: Relationship to idiopathic scoliosis curve pattern and curve size. Spine (Accepted) Branthwaite, M.A.: Cardiorespiratory consequences of unfused idiopathic scoliosis. Br J Dis Chest 80:360-369, 1986. Collis, O.K.; Ponseti, I.V.: Long-term follow up of patients with idiopathic scoliosis not treated surgically. J Bone Joint Surg 51-A:425-445, 1969 (12). Connolly, P.J.; Von Schroeder, H.P.; Johnson, G.E.; and Kostuik, J.P.: Adolescent idiopathic scoliosis. Long-term effect of instrumentation extending to the lumbar spine. J Bone Joint Surg 77-A:1210-1216, 1995 (14). Danielsson, A.J.; Nachemson, A.L.: Radiographic findings and curve progression twenty-two years after treatment for adolescent idiopathic scoliosis-Comparison of brace and surgical treatment and with a matching control group of straight individuals. Spine 26:516-525,2001. Dickson, J.H.; Erwin, W.D.; Rossi, D.: Harrington instrumentation and arthrodesis for idiopathic scoliosis: A twenty-one year follow up. J Bone Joint Surg 72-A:678-683, 1990 (18). Dickson, J.H.; Mirkovic, S.; Noble, P.C.; Nalty, T.; and Erwin, W.: Results of operative treatment of idiopathic scoliosis in adults. J Bone Joint Surg 77-A: 513-523, 1995. Goldberg, C.J.; Dowling, F.E.; Hall, J.E.; and Emans, J.B.: A statistical comparison between natural history of idiopathic scoliosis and brace treatment in skeletally immature adolescent girls. Spine 18:902-908, 1993. Harol J: The clinical appearance of low back disorders in the city of Goteberg, Sweden. Acta Orthop Scand M8{Suppl}, 1969 Lenke, L.G.; Bridwell, K.H.; Blanke, K..; Baldus, C.; Weston, J.: Radiographic results of arthrodesis with Cotrel-Dubousset instrumentation for the treatment of adolescent idiopathic scoliosis: A five to ten year follow up study. J Bone Joint Surg 80A.-807-814,1998. Mayo, N.E.; Goldberg, M.S.; Poitras, B.; Scott, S.; Hanley, J.: The Ste-Justine Idiopathic Scoliosis Cohort Study. Part III: Back pain. Spine: 19:1573-1581, 1994. Nachemson, A.L.; Peterson, L-E.; and members of the brace study group of the scoliosis research society: Effectiveness of treatment with a brace in girls who had adolescent idiopathic scoliosis. J Bone Joint Surg 77-A: 815-822, 1995.

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13.

Noonan K.J.; Dolan, L.A. Jacobson, W.C.; and Weinstein, S.L.: Long-term psychosocial characteristics of patients treatment for idiopathic scoliosis. J Pediatr Orthop 17:712-717 1997.

14.

Pehrsson, K.; Blake, B.; Larsson, S.; Nachemson, A.: Lung function in adult idiopathic scoliosis: A 20 year follow up. Thorax 46:474-478,1991. Pehrsson, K.; Larsson, S.; Oden, A.; and Nachemson, A.: Long-term follow-up of patients treated with untreated scoliosis. A study of mortality, causes of death, and symptoms. Spine 17(9): 10911096,1992. Rowe, D.E.; Bernstein, S.M.; Riddick, M.F.; Adler, F.; Emans, J.B.; and Gardner-Bonneau, D.: A meta-analysis of the efficacy of non-operative treatment for idiopathic scoliosis. J Bone Joint Surg 19-A:664, 1997. Sponsellor, P.D.; Cohen, M.S.; Nachemson, A.L.; Hall, I.E.; Wohl, M.B.: Results of surgical treatment of adults with idiopathic scoliosis. J Bone Joint Surg 69A:667-675,1987 (78). Weinstein, S.L.; Zavala, D.C.; Ponseti, I.V.: Idiopathic scoliosis. Long term follow up and prognosis in untreated patients. J Bone Joint Surg 63A:702-712,1981. Weinstein, S.L.: Long term follow-up of pediatric orthopaedic conditions: Natural history and outcomes of treatment. J Bone Joint Surg 82-A: 980-990,2000.

15.

16.

17. 18. 19.

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Quantitative Measurement of Spinal Brace Use and Compliance in the Treatment of Adolescent Idiopathic Scoliosis G.P. Nicholson1; M.W. Ferguson-Pell1; K. Smith2; M. Edgar2; T. Morley2

1. Centre for Disability Research and Innovation, Institute of Orthopaedics and Musculo Skeletal Sciences, University College London, Brockley Hill, Stanmore, HA 7 4LP. 2. Royal National Orthopaedic Hospital Trust, Brockley Hill, Stanmore , UK, HA 7 4LP.

Sources of support: RNOH Board of Clinical Studies and ASPIRE

Abstract. The objective measurement of compliance with spinal bracing in adolescents with idiopathic scoliosis (AIS) is fundamental in the validation of clinical trials of bracing effectiveness, and in helping clinicians better understand reasons behind poor compliance. Current technology has been developed and tested for discrete, reliable and objective measurement of the times of day a brace is worn and consistency in its use. TLSOs were instrumented with data loggers measuring temperature at the skin/brace interface at 16 minutes intervals over a period of 88 days; between routine follow up and without patient interference. 10 female patients (age 14 years, sd 1.1) with AIS using spinal bracing as part of their treatment regime took part in the study over 15 months. Skin/brace interface temperature during periods of wear in the UK was >30°C, ambient 23°C, sd 4. Compliance ranged from 8-90%, average 65%. Patients tended to over estimate their compliance by ISO % (sd 50%). There was no significant difference between weekday and weekend compliance but wear patterns differed. Nightwear was significantly greater than daywear. Patients with very good compliance only removed their brace for washing or exercise periods but where poor compliance was evident, the brace was only worn sporadically during the day. Temperature provides a clear signal of brace use and can be used for long-term data logging using discrete instrumentation, providing a tool to help identify and understand the reasons behind poor compliance.

1. Introduction

Adolescent Idiopathic scoliosis (AIS) is a deformity of the spine, characterised by lateral curvature and vertebral rotation; cause still unknown. It is in danger of progressing during the years of greatest skeletal growth and if left untreated will cause increased symptoms, especially those involving the respiratory system. Conservative treatment consists of regular monitoring using observation and radiography to assess progression of the deformity, and if warranted spinal bracing to try and prevent it from

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worsening and so prevent surgery. Currently, clinicians specify that braces should be worn for 20-23 hours a day. However, there is little objective evidence to recommend the actual number of hours a brace should be worn. The accurate measurement of compliance with this treatment regime is fundamental in validating clinical trials of bracing effectiveness, and help clinicians understand reason's for non-compliance. Wearing a brace isn't fashionable, restricts movement and may be uncomfortable, especially as the patient grows out of the brace. Historically, the "time in brace" has been measured subjectively by questionnaire, interview, or for signs of brace wear and fatigue. This has suggested 38100% of patients in the studies complied with their prescribed regime1"2 and actual compliance ranged between 58-98%3' . From such information the clinician could only make subjective judgement upon whether compliance was adequate, realising this information may not be particularly accurate. It also made it extremely difficult to show any significance in trials on the effectiveness of bracing, especially when comparing full time and part time use. In recent years several quantitative techniques have been used to measure compliance. These included skin/brace interface temperature5, strap tension4 and skin/brace interface force6'7. This work has shown that actual time in brace is less than reported by the user and clinical judgment of brace use is not a reliable way to distinguish between compliant and non-compliant users. However, doubts have been expressed as to the validity of these quantitative methods. Point force measurement cannot reliably distinguish whether zero force indicates no brace use or the sensor is unloaded when the brace is being worn. These devices are generally too bulky for discrete long term monitoring or require permanent connection to a computer, limiting their use to laboratory devices or short-term (days) remote data loggers, requiring intervention by the patient. Temperature measurement at the skin/brace interface5 gave an unambiguous signal of time in brace but did not record information on daily use. As technology has evolved it is now possible to develop smaller discrete temperature data loggers with large memory capacity and high sampling frequency. This paper presents work on developing and testing these devices to measure the times of day the brace is worn and consistency in using the brace. 2. Methods The "time in brace" was determined by monitoring the skin/brace interface temperature. Bracing materials have poor thermal conductivity and the temperature will be similar to body temperature, and very different from ambient temperature, especially in the UK. Two data loggers were tested, each comprised sensor, real time clock, memory and power source. Their size did not affect the efficacy of the brace nor change its appearance, were acceptable to the patient and did not interfere with their daily routine. They also withstood harsh treatment such as washing and being dropped. A HOBO H8 temperature data logger (Onset Computer Corporation, MA, USA), modified to reduce its size to 70x45x6 mm, was placed in a hole cut in the back of the brace and sandwiched between two layers of closed cell foam, the inner one being

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perforated to allow air to circulate. The logger was wrapped in aluminium foil and a liquid proof/vapour permeable membrane to protect it from electromagnetic interference, static, and washing. 7920 date/time stamped points were logged at 16 minutes intervals over a period of 88 days. The data logger was fitted, launched and the data downloaded at normal routine visits to the orthotics department, not extending the visit by more than 15 minutes. 10 female subjects (average age 15 yrs, sd 1.2) with AIS (Thoraco-lumbar) took part in the study over a period of 14 months, sd 4.5. Actual logging time spread over this period was 3.4 months, sd 1.2. The subjects had a period of scoliosis 29 months, sd 22, and had been in bracing 16 months ± sd 9.5. The average number of braces was 3 (sd 1.3) and average period between braces 8 months, sd 7.3. IButton Thermochron data loggers (Dallas Semiconductors, CA, USA) were compared with the HOBO devices on a single patient and a trial is underway to assess suitability for long term monitoring in terms of reliability and patient acceptability. The iButtons are very small devices in environmentally sealed cans, 17mm diameter by 6-mm thick, and fitted to the brace in the same manner as a rivet. These loggers store up to 2048 date/time stamped values, but can be wired together to increase it, and can also store up to 65,536 temperature values as a histogram giving compliance only information. 3. Results Temperature at the skin/brace interface was 32.8°C (sd 1.6°C) and a clear threshold for time in brace was 30°C (e.g. Fig 1), unworn brace temperature was 23.3°C (sd 3.6°C). Compliance with the treatment regime was determined by dividing the measured hours worn with the time specified by the clinician for the brace to be worn. The average weekly compliance was 65% (sd 25%), range 8%-90% (Table 1). For all subjects there was no significant difference between weekday and weekend wear compliance (Student paired t-test, P>0.05). For all subject data there was a significant difference (Student paired t-test, P30°C this clearly indicated the "time in brace". The average compliance measured in this paper was 65%, closely matching previous studies. The patient's estimated compliance was 89%, tending to overestimate by as much as 200%. However, it was apparent the patient was not deliberately misleading but attempted to judge compliance accurately, admitting poor compliance where applicable.

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There was no significant difference in average compliance between weekday and weekend wear. However, closer examination of the daily wear profiles showed there was an observed difference in use patterns. For example, it was clear that at weekends some patients had a greater lie in period in the morning and wore the brace less during the rest of the day. There was a significant difference between average daytime and night time wear, primarily due to the large differences for individuals with compliance 2. Bracing is currently the accepted nonoperative treatment to prevent curve progression in mild to moderate scoliosis during the growth period. Corresponding to the natural history of untreated curves, Lonstein and Winter3 found a relationship between the final outcome of brace treatment and curve factors and factors that predict future skeletal growth. Factors that predict potential remaining skeletal growth do not always predict spinal growth correctly. Only a few studies have concentrated on the correlation between direct radiologic measurements of spinal growth and the progression of the scoliotic curve4. The present study evaluated the velocity of spinal growth, measured with the length of the scoliotic spine on longitudinal series radiographs, and its relationship to the progression of the scoliotic curve. Progression is evaluated in terms of Cobb angle, lateral deviation, and axial rotation increase in the period before brace therapy and during the time the brace was worn.

2. Materials and methods Patient group The longitudinal study was based on measurements made on conventional standing anteroposterior (AP) radiographs of 54 girls with adolescent idiopathic scoliosis. In all patients, a Boston brace was prescribed during the followup period. This brace treatment was indicated in skeletally immature patients with a Cobb angle between 20°

388

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and 45°. Patients who underwent surgical procedures performed during the followup period were excluded from the study. Radiographs of the patients from their first visit to the clinic until skeletal growth was completed were used for the study. The mean age of the patients at diagnosis was 11.1 (standard deviation, 2.01 years). All had a major thoracic curve with the apex between T6 and T12. The mean Cobb angle on the first radiographs of the thoracic curves was 25.9° (standard deviation, 8.69°). Subsequent radiographs were taken at 4 to 6 month intervals with the patients in the standing position using the same standardized method. Radiological measurements For the radiographic measurements, six landmarks per vertebra on each AP radiograph were identified and marked with a fine white ink pen (point size: 0.4 mm). These landmarks were positioned at the corners of the vertebral bodies and the inner edges of both pedicles from Tl to L4. The corners of the vertebrae were determined by means of tangent lines through the upper and lower endplates and both lateral sides of the vertebrae. The landmarks were scanned with a MX5 CCD camera (Adimec, Eindhoven) and digitized with the Bioscan OPTIMAS* (V4.1, Bioscan Inc, Washington, Virginia) software package. The accuracy of identifying the anatomic landmarks was assessed in 20 radiographs taken at random during the study. The average variability of the digitized landmarks was 0.42 mm for the horizontal coordinates and 0.75 mm for the vertical coordinates. With the two-dimensional coordinates of the landmarks, the midpoints of the vertebral bodies and the lateral tilt of the upper and lower end plates of each vertebra were calculated by a computer algorithm. The lateral deviation for each vertebra was measured as the distance between the calculated midpoint of the vertebral bodies and the line passing through the centers of the upper end plate of Tl and the lower end plate of L4. The axial rotation was determined with a method adapted from Stokes et als. The length of the scoliotic spine was determined through the distance of the line through the midpoints of all vertebrae and discs between the upper end plate of Tl and the lower end plate of L4. All these measured dimensions on the AP radiographs have been corrected for the magnification. The spinal length measured on two consecutive radiographs, was used to calculate the growth velocity in millimeters per year. With these data, a spinal growth velocity curve was determined for each patient during the followup period. Subsequently, the followup period was divided into three phases, a phase of rapid spinal growth, a phase of moderate growth, and a phase of little or no spinal growth. On the basis of the mean spinal growth velocity values of all 54 female patients in the study, these three phases were quantified. In the various growth phases the mean increase of the Cobb angle, the mean increase of the lateral deviation, and the mean increase of the axial rotation were determined. A distinction was made between curve progression rate before brace treatment and curve progression during brace treatment.

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3. Results Spinal gowth velocity The median, fifth, twenty-fifth, seventy-fifth and ninety-fifth percentiles of the spinal growth velocity of the female patients, fitted with a third-grade polynomial (r2 = 0.93) are presented Figure 1. The maximum spinal growth velocity of the female patients was found to be between the ages of 11.5 and 12.5 years. The mean maximum growth velocity was 18.3 mm per year which extended from approximately 10 to 30 mm per year. The remaining growth of T1-L4 versus age, derived from the growth velocity rates of the patients in this study is presented in Figure 2. On the basis of the spinal growth velocity curve of the female patients, the period of the most rapid growth was defined as the period in which spinal growth exceeded 20 mm per year, the period with moderate growth as the period with a growth velocity between 10 and 20 mm per year, and the period with the least rapid growth as the period in which the growth velocity did not exceed 10 mm per year. Progression rate The mean progression rate of the Cobb angle, lateral deviation, and axial rotation of the thoracic curve of all patients in the three growth phases is presented in Table 1. A distinction has been made between the progression rate in the period before brace treatment and the progression rate during brace treatment. The mean progression rate in the phase of little growth was found to be significantly smaller compared with the mean progression rate in the phases with moderate and a large spinal growth velocity. This observation was valid for the Cobb angle, the lateral deviation, and the axial rotation increase. A significantly smaller mean progression rate of the Cobb angle was observed in the group which was treated with a brace than in the group which had not yet been treated with a brace. This brace effect could not be seen in the progression rate of the lateral deviation and axial rotation. 4. Discussion In this study, spinal growth was measured with the length increase of the scoliotic spine (T1-L4) on longitudinal standing AP radiographs. A significantly greater average progression rate of the scoliotic thoracic curve was found in the periods with rapid to moderate growth (> 10 mm per year) compared with the periods with small or no growth (< 10 mm per year). The difference in progression rates concerned the increase of the Cobb angle and the increase of the lateral deviation and axial rotation. Despite curve progression during the growth periods, the brace treatment had a significant effect on the Cobb angle increase. This brace effect, however, could not be seen for the progression rate of the lateral deviation and axial rotation. These results are in agreement with recent studies concerning the three dimensional analysis of the shortterm effects of the Boston brace system6.

D.J Wc\:er el al. / Curve Progression and Spinal Growth

asm.75m.2S0i.Mi

Fig l

The median, 95th, 75th, 25th and 5th percentiles of the spinal growth velocity at consecutive chronologic ages of the patients. The different percentiles of the growth velocity were fitted with a third grade polynomial (r2 = 0.93). ~l

Remaning '» Grow* T1-14

(mm)

too

I

t

10 11 12 11 14 is

ie

u

Chronologic*

Fig 2

The median, 95th, 75th, 25th and 5th percentiles of the remaining spinal growth at consecutive chronological ages of the patients. The different percentiles of the growth velocity were fitted with a third grade polynomial (r2 = 0.99).

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Growth charts were derived from the measured individual growth velocity values of the patients of the study. At the age of 10 years an average length increase of 10 cm of the T1-L4 segment is expected, which varies from 4.5 cm to 17 cm. This variation in growth speed per individual may be an explanation for the variation of expression of idiopathic scoliosis. After the age of 16.5 years the growth speed barely exceeds 10 mm per year, the growth speed under which only small progression should be expected on the basis of the data of the current study. In conclusion, it is clear that the length of the spine measured on subsequent radiographs is an excellent parameter to determine spinal growth and therefore an excellent predictor of scoliosis progression. The current advance of digital radiographs makes it possible to easily quantify various geometric variables of the scoliotic curve. In addition to the various three dimensional parameters, the length of spine is an important variable for the clinician to determine the growth of the patient with scoliosis.

References 1. 2.

3. 4. 5. 6.

Lonstein JE, Carlson JM: The prediction of curve progression in untreated idiopathic scoliosis during growth. J Bone Joint Surg 66 A:106\-\Q71, 1984. Peterson LE, Nachemson AL: Prediction of progression of the curve in girls who have adolescent idiopathic scoliosis of moderate severity. Logistic regression analysis based on data from The Brace Study of the Scoliosis Research Society. J Bone Joint Surg 77A:823-827, 1995. Lonstein JE, Winter RB: The Milwaukee brace for the treatment of adolescent idiopathic scoliosis. A review of one thousand and twenty patients. J Bone Joint Surg 76:1207-1221,1994. Ylikoski M: Spinal growth and progression of adolescent idiopathic scoliosis. Eur Spine J 1:236-239, 1993. Stokes LAP, Bigalow LC, Moreland MS: Measurement of axial rotation of vertebrae in scoliosis. Spine 11:213-218,1986. Aubin CE, Dansereau J, de Guise JA, Labelle H: Rib cage-spine coupling patterns involved in brace treatment of adolescent idiopathic scoliosis. Spine 22:629-635, 1997.

Table 1

The mean progression rate of the thoracic curve of all patients, in the period before brace treatment, and during brace treatment, in the three growth phases.

Growth rate < 1 o mm/year

Progress! on rate

Growth rate >10, 20 mm/year Mean

SEM

n

8

6.8

1.34

12

33

3.3*

1.40

12

Cobb angle increase (degrees/year) No Brace Brace Lateral deviation increase (mm/year) No Brace Brace

4.6

1.41

8

5.7

1.48

12

4.0

0.94

33

5.1

2.17

12

3.6

0.98

8

4.4

1.31

12

3.3

0.67

25

4.1

2.07

10

Axial rotation increase (degrees/year) No Brace Brace SEM

standard error of the mean

*

Significant different from no brace group (Mann-Whitney U test; p < 0.05)

**

Significant different from other growth velocity groups (Kruskal Walls H test; p < 0.05)

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Personalized Biomechanical Modeling of Boston Brace Treatment in Idiopathic Scoliosis D. Perie D., C.E. Aubin Ph.D., M. Lacroix B.Eng., Y. Lafon B.Eng., J. Dansereau Ph.D., H. Labelle H. M.D. 1 - Canada Research Chair "CAD Innovations in Orthopedic Engineering ", Ecole Polytechnique, PO Box 6079, Downton St., Montreal (Quebec) Canada H3C 3A7 2 - Research Center, Sainte-Justine Mother-Child University Hospital, 3175 Cote-Sainte-Catherine Rd, Montreal (Quebec) Canada H3T1C5 Abstract. The aim of this study was to describe how the Boston brace modify the scoliotic curvatures using a finite element (FE) model and experimental measurements. The experimental protocol, applied on 12 scoliotic girls, was composed of the pressure measurement at the brace-torso interface followed by two radiographic acquisitions of the patient's torso with and without brace. A 3D FE model of the trunk was built for each unbraced patient. The brace treatment was represented by two different modeling approaches: 1) using equivalent forces calculated from the measured pressures; 2) by an explicit personalized FE model of the brace (hexahedral elements) and its interface with the torso (contact elements). In the first model, measured brace forces less than 40N and up to 113N induced respectively less than 21% and up to 87% of real correction. Thoracic forces induced the main correction, affecting partially both lumbar and thoracic curves, in agreement with the literature. In the second model, the brace closing reduced the curves up to 35% of real correction. Contact reaction forces (16-79N) were similar to real brace forces (11-72N). The results suggested that other mechanisms than brace pads contribute to the equilibrium of the patients. Postural control by the muscular system remains a problem to address in a future study. The second model represented more realistically the load transfer from the brace to the spine than external forces application. With such model, it is expected to predict the effect of a brace before its design and manufacturing, and also to improve its design.

1. Introduction and objectives In the literature few biomechanical studies were conducted to assess brace effectiveness in the treatment of idiopathic scoliosis. Strap tensions and pad pressure were measured within the Boston and Milwaukee braces. But the way these loads modify the 3D spine curvatures was not clearly described. Biomechanical models were developed to simulate and analyze brace biomechanics [1, 2, 3, 4, 5]. External forces representing brace pads were applied to specific scoliotic patient's geometry. This way of modeling is not truly realistic since brace loads are in fact reaction forces and are depending on the relative flexibility and geometry of the brace and trunk. Also, the complex mechanical action of the brace on the entire torso was not completely addressed. The aim of this study was to describe how the Boston brace modify the scoliotic curvatures using a finite element (FE) model and experimental measurements. Two different approaches of the brace treatment modeling were proposed and compared.

3^4

/). Peru1 ct til. / Pci'soiHiti-t'el Hioniecluintcal Modeling of Boston Brace Ii'ciitnirnt

2. Materials and Methods Eleven girls (13-14 years old) were recruited from the scoliosis clinic at Sainte-Justine Hospital on a volunteer basis. The subjects were having progressive adolescent idiopathic scoliosis. The average spine deformity was measured at 36/E±7JE and 27vfi±8/t of Cobb angle respectively for the thoracic and lumbar segments, with apical vertebrae in T7-T12 and L1-L4. They were all treated by a Boston brace system. Two radiographic acquisitions of the patient's torso geometry (standard posteroanterior (PA), PA with a 2(h€ angle down pitch, and lateral) were done, the first one without the brace and the second wearing the brace (Fig. 1-a). It was followed by the measurement of the pressure at the brace-toYso interface (Fig. 1-b). The entire protocol was performed at the brace delivery within the same hour, and was approved by the hospital

ethic committee. A FE model of the trunk [2, 6, 7] was built for each patient without brace (Fig. 2a). The thoracic and lumbar vertebrae, intervertebral discs, ribs, sternum and cartilages were represented by 3D elastic beam elements. A detailed modeling of costo-vertebral, costotransverse and zygapophyseal joints was developed using point-to-surface contact, shell and multilinear elements. The vertebral and intercostal ligaments were represented by 3D elastic spring elements. The mechanical properties were taken from experimental data [7J. The brace treatment was represented by two different modeling approaches: 1) using equivalent forces calculated from the measured pressures (Fig. 2-a); 2) by an explicit personalized FE model of the brace (hexahedral elements) and its interface with the torso (contact elements) (Fig. 2-b). The first brace treatment modeling was simulated in 3 successive load steps. The first one consisted in applying the lumbar forces, then in adding the thoracic forces and finally in applying the real in-brace displacement of Tl (which approximated the patient's righting reflex). The second brace treatment modeling was simulated in 3 successive (different) load steps: 1) the brace opening, 2) the brace translation onto the trunk (to include the patient's trunk); and 3) the brace closing. In both approaches, the lowest available vertebra or the pelvis was fixed. The deformed geometry of the patient's trunk was computed at each load step and compared to the real in-brace geometry by means of several computed geometric

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parameters. The reaction forces in contact elements were compared to equivalent forces calculated from the measured pressures. 3. Results Two Boston brace force patterns were identified. The first one consisted in high right thoracic forces of 56-113N and lumbar forces less than 47N. The second one consisted in low thoracic forces less than 20N and lumbar forces up to 70N. Using the first model (Fig. 3-a), these passive forces produced up to 9JE of Cobb angle correction and up to 20mm of vertebral displacements. Brace forces less than 40N entailed less than 21% of real correction. Brace forces up to 113N entailed up to 87% of real correction.

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Contact reaction forces of 16-79N were obtained form the second model, while measured forces were in the range 11-72N. The closed contact nodes of the model were located near the application node of the measured force (standard deviation of 6 cm). The brace closing reduced the spinal curvatures up to 35% of real correction.

4. Discussion The results of the first brace treatment model showed that high thoracic pads reduced more effectively both thoracic and lumbar scoliotic curves than lumbar pads. The response of this model to the application of the passive external forces should be interpreted with caution because of the boundary conditions (zero displacement applied to L5 and Tl). Also, the lumbar forces were applied directly on the spine while the effective loads could be different from pressure measurements. The second biomechanical model of the trunk used in this study is considered as an improvement over previous biomechanical models developed for orthotic treatment simulations because of the explicit patient-specific representation of the brace. This way of modeling is more appropriate that the traditional application of external loads because brace loads are in fact reaction forces and are depending on the relative flexibility and geometry of the brace and trunk.. This study showed the feasibility and the interest of such novel approach to analyze brace biomechanics. This model represents more realistically the load transfer from the brace to the spine than the external forces application. For both brace treatment models, the results suggested that other mechanisms than brace pads produce correction and contribute to the force equilibrium within the brace. Postural control by the muscular system remains a problem in this study. This phenomenon is difficult to quantify. An active representation of the muscles in the model should improve the simulations.

References 1. 2. 3. 4. 5. 6. 7.

Andriacchi et al. (1976) Milwaukee brace correction of idiopathic scoliosis. J. Bone and Joint Surg. 58A(6): 806-815. Aubin et al. (2002), Personalized Biomechanical Simulations of Orthotic Treatment in Idiopathic Scoliosis. J. Orthop. Research, in revision. Gignac et al. (2000), Optimization method for 3D bracing correction of scoliosis using a finite element model. Eur. Spine J. 9:185-190. Parwardan et al. (1986), A biomechanical analog of curve progression and orthotic stabilization in idiopathic scoliosis. J. Biomech. 19-2: 103-117. Wynarsky et ai. (1991) Optimization of skeletal configuration: studies of scoliosis correction biomechanics. J. Biomech. 24-8, 721-732. Aubin C.E. et al. (1995) Geometrical modeling of the spine and thorax for biomechanical analysis of scoliotic deformities using finite element method (in French). Ann. Chir. 49(8), 749-761. Descrimes J.L., Aubin C.E. et al.,, (1995): Introduction des facettes articulaires dans une modelisation par dements finis de la colonne vertebrale et du thorax scoliotique: aspects mecaniques, Rachis, 7:5, 301-314.

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Intelligent Brace System for the Treatment of Scoliosis E. Lou1, D. Benfield1, J. Raso1, D. Hill1, N. Durdle2 'Capital Health Authority, Glenrose Site, 10230-111 Ave Edmonton AB, Canada T5G OB7 2 University of Alberta, Edmonton, AB, Canada T6G 2G7 email: [email protected]

Abstract Measurement of the biomechanical effectiveness of a brace for the treatment of scoliosis has been hampered by the lack of compressive information about wear characteristics. Orthotists and orthopaedic surgeons believe that the effectiveness of bracing is correlated with the strap tensions. If the strap tensions can be maintained at the optimal level while patients wear their braces, a better treatment outcome may be obtained. However, strap tensions vary significantly during different activities. An intelligent brace system has been developed to control the strap tension so that the optimal prescribed level is maintained at all time. This system consists of an innovative strap tension transducer, a microcomputer unit and a motorized unit. The strap transducer has been developed with an accuracy ±1.0N in the range of 0 to 100N. An instrumented Boston brace was built to test the concept. When the strap tension was below 80% of the prescribed level for a 15 minutes interval, the microcomputer unit signaled the motor to tighten the strap. While the strap tension level was above 120% of the prescribed level for a IS minutes interval, the motor reversed the direction. Laboratory testing results showed that the strap tension could be maintained at the optimal prescribed level.

1. Introduction Scoliosis is an abnormal curvature of the spine with vertebral rotation. Brace treatment is the most commonly used in non-surgical treatment for patients who have potentially progressive spinal deformity. The primary purpose of brace treatment is to prevent further increase of spinal curvature. However, the effectiveness of bracing is uncertain [1,2]. The amount of support and corrective action provided by a brace depends on the location, magnitude and direction of the pressures exerted upon the spine [3]. Successful brace treatment is thought to require patients to wear braces as prescribed, including securing the straps to provide a level of pressure on the convexity of the curve. Opinion concerning the effectiveness of braces turns on two points: do patients wear the brace as prescribed and is the correction due to mechanical support. By examining in-brace curvatures, Willner [4] showed that lateral forces are more important than elongation forces to the correction of spinal deformities. Jiang et al [5] measured the magnitude, location and direction of pressure generated by the brace as well as the forces in the straps, and found that there was considerable variation in how braces are worn by patients. Some children secured the brace very aggressively and imposed high loads on their trunks; other children, who wore the brace loosely, imposed little pressures. Wong et al [6] found that the standing Cobb angle correlated with the pressure pad and the

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strap tension. If the strap tension of the brace can be adjusted automatically and maintained at the prescribed level, optimal treatment outcome may be obtained. 2. Objective The purpose of this study was to determine whether the strap tension was able to be controlled by a microcomputer system to maintain the strap tension at the optimal prescribed level. 3. Methods and Materials The intelligent brace system consists of a strap tension transducer, a microcomputer unit and a mechanical motor system (Figure 1). The strap tension transducer will be mounted at the top buckle position to measure the strap tension. The microcomputer unit will be carried while a subject wears her brace. The motor system is used to control the tightness of the strap tension. 3.1 The Strap Tension Transducer The instrumented strap tension transducer was built by the authors. The constraints were that it was small, consumed low power, sensitive over the load range, non-obtrusive and cost effective. The transducer consisted of an aluminum ring in the center with two brass rectangular loops at each end (Figure 2). Four strain gauges were mounted on the aluminum ring (2 on the outer surface and 2 on the inner surface) and formed a wheatstone bridge circuitry. Each pair of strain gauges provided temperature compensation and greater the sensitivity. The electronics with amplifier were mounted close to the transducer so that electronic noise picked up from the strain gauge fine wires to the amplifier was minimized. The voltage from the transducer was linearly proportional to the applied tension. ^ Motorized system J Microcomputer Unit Strap tension transducer

Figure 1. Block diagram of the brace system.

Figure 2. An instrumented strap tension transducer.

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3.2 The microcomputer unit The microcomputer unit consisted of a microcontroller and memory with associated circuitry, battery recharging circuit and rechargeable battery. The unit was packaged in a box with dimensions 55mm x 80mm x 20mm and its weight was only 60g. The system was easily to carry and hide under clothes. This unit has been used for measuring forces and compliance during daily activity [7]. Only the software was modified to control the motor. Patients use a belt clip or velco to carry the system while they wear their braces. The system requires recharging everyday for a maximum 2 hours. Data stored in memory can be downloaded for further analysis. 3.3 The motorized system The mechanical motor system consisted of a motor with a gearmotor mechanic. The selection of motor was very challenging. The motor was required to be small and consume low power, but at the same time it had to provide enough torque to adjust and hold the strap. Also, a safety release was necessary in case of the malfunction of the motor. If the strap tension was below 80% of the prescribed level for a 15 minute interval, the microcomputer unit caused the motor to tighten the strap tension level. When the strap tension level was above 120% of the prescribed level for a 15 minute interval, the motor reversed the direction. The motor with its gear mechanism can hold loading up to SON. The frequency of strap adjustment is software controllable and is a trade-off between power consumption, subject intrusiveness and effectiveness. When adjusting the strap tension, the motor was loosened or tightened a fixed amount. It is necessary to prevent the motor from tightening the strap too much. Excessive loosening although causing the brace to be less effective does not cause a safety risk. Having the brace too tight could impose excessive loads upon the body and also damage the mechanism. The limiting of the active motor was controlled by software. 4. Laboratory Experiments and Results An instrumented Boston brace (Figure 3) was developed to test the concept of controlling strap tension by using the microcomputer system. The strap tension transducer was calibrated by hanging weights on one side and fixing the other end. Three trials of loading and unloading experiments were performed. Calibration (Figure 4) showed that the system could calculate the forces accurately to within ±1N with resolution ±0.5N. 4 3.532.5-

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The instrumented Boston brace was tested after the buckle transducer was calibrated. An air bladder was put inside the brace and inflated to known pressure levels using a standard blood pressure measurement gauge. In practice, an orthotist will set the prescribed tightness of the brace. The microcomputer will "learn" and record the corresponding strap tension. In this test, the prescribed level was set at 18N. The trigger points were set at 80% and 120% of the target level. Tightening occurred when the pressure was below 80% of the target (14N) for 15 minutes (30 consecutive samples at 1 sample per 30 seconds). Loosening occurred when the pressure was above 120% of the target (22N) for 15 minutes. During tightening or loosening the sample rate was increased to 1 sample per 10 seconds. The air bladder was inflated and deflated to level below and above the trigger points to verify correct operation of the unit. 5. Conclusions and Future work A prototype intelligent brace had been developed to prove that the strap tension was able to be controlled and maintained at the optimal prescribed level. However, the actual design of the motorized system still requires improvement. A safe mechanism and a motor with higher loading specifications are required. Clinical trials will be conducted in future. References 1. 2. 3. 4. 5. 6. 7

M. A. Asher and W. H. Whitney, Orthotics for Spinal Deformity, Orthotics Etcetera, Baltimore, 1986. R. G. Houghton et al., Monitoring True Brace Compliance. Proceedings of the 21st. Meeting of the Scoliosis Research Society, Hamilton, 21-25 September 1986, 101. G. T. Wynarsky, A. B. Schultz, Trunk Muscle Activities in Braced Scoliosis Patients. Spine 14 (1989), 1283-1286. S. Willner, The effect of the Boston brace on the frontal and sagittal curves of the spine. Ada Orthop Scand, 55 (1984), 457-460. H. Jiang et al., Interface Pressures in the Boston Brace Treatment for Scoliosis. Proceedings Int'l Symposium on 3-D Scoliotic Deformities, Montreal, 27-30 June 1992,395-399. M. S. Wong et at., Effectiveness and biomechanics of spinal orthoses in the treatment of adolescent idiopathic scoliosis (AIS).' Prosthetics & Orthotics International, 24, (2000), 148-162. E. Lou et al., The Daily Force Pattern of Spinal Orthoses in subject with Adolescent Idiopathic Scoliosis. Prosthetics and Orthotics International, 26, (2002) 59-63.

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Spine-Straight Device for the Treatment of Kyphosis E. Lou1, J. Raso1, D. Hill1, N.Durdle2, M.Moreau2 'Capital Health Authority, Glenrose Site, 10230-111 Ave Edmonton AB, Canada T5G OBJ 2 University ofrfAlberta, Alberta, Edmonton, Edmonton, AB, Canada Cane T6G 2G7 email: edmond [email protected]

Abstract Kyphosis is an excessive rounding of the upper spine. Its treatment depends upon the severity, the age of the patient and the levels of the spine that are affected. Early diagnosis is a key to providing optimal treatment. In a skeletally immature patient, an exercise program or bracing is the most commonly used treatment. However, the compliance of bracing for adolescents is poor and exercise training is labor intensive. The purpose of this study is to determine whether a Spine-Straight device can help patients to correct their kyphosis themselves and there by reduce back pain without the biomechanical support of a brace. The Spine-Straight device consists of an accelerometer and a microcomputer unit. The accelerometer is used to measure the kyphotic angle and the microcomputer unit controls a pager vibrator to alert patients when their posture exceeds personalized thresholds. The system was tested in the laboratory before used by subjects. The results were compared to back data obtained from a laser scanner imaging system. The maximum angle deviation between the laser scanner and the Spine-Straight device was 1.5 degrees. Two volunteers tested the systems for 2 days. The accelerometer was placed at the T3 location and the microcomputer unit was carried during daily activities. The angle measurement was recorded at 1 minute intervals during daily activity over a period of 2 days. The preliminary trials demonstrate subjects can improve their posture when feedback signals were provided.

1. Introduction Kyphosis is defined as standing in a hunched over posture with shoulders drooped forward. Kyphosis results from a variety of causes. The most common cause for kyphosis is purely postural. Children stand in a hunched over position for a variety of non-physical reasons: it is easier, they may be lazy, they may have low self-esteem, or, in adolescent girls, they may slouch to hide developing breasts [1]. Poor posture usually worsens during the adolescent growth spurt, when a child may assume a more pronounced round back. Poor posture of this form, in which no underlying deformity or disease exists, is known as postural round back and usually is a correctable situation. The diagnosis of postural round back can be made in two ways. First, determination of the flexibility of the spine - during examination the roundness corrects with hyperextension (bending backwards) or improvement of posture by the patient. When the child bends forward, a smooth gentle curve is seen, as opposed to a sharp peak as seen in Scheuermann's disease. The second way to diagnose postural round back is by exclusion ruling out other causes through radiographs. The standard treatment for postural round back is education regarding proper sitting and standing. For children who continue to stand in a slouched position, an exercise program is the second line of treatment. Exercises can strengthen the scapular muscles and spine extensor muscles. Typically, a physical therapist teaches an exercise regimen to the child and

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sets up a program for the patient to do at home. The therapist is required to periodically meet with the child, to assure that the exercises continue to be done properly. The sooner physical therapy is started, the less likely the child will end up with a humpback deformity. Everyone has kyphosis to some extent, and curves as seen on radiographs of 20 to 40 degrees are considered normal. For curves over 40 degrees, an exercise program is beneficial. Surgery will not generally be performed unless the curve goes beyond 75 degrees. If exercises are not effective in reducing the kyphosis, then a brace may be used. Bracing can be effective for kyphosis in the growing child if patients are compliant. However, the exercise program is labor intensive and the compliance for bracing is poor. An un-obtrusive selfteaching device has been developed to provide an alternative treatment for kyphosis.

2. Objective The purpose of this study was to determine whether a Spine-Straight device could detect the postural changes during daily activities and help patients to correct their kyphosis. 3. Constraints 1. Spine-Straight device compliance must be higher than brace compliance. 1. Spine-Straight device reduces the overhead cost. 1. Subjects must be able to improve their kyphosis when feedback is given.

4. Methods and Materials An accelerometer, 1 .Ocm x 1 .Ocm x 0.6cm, was attached to the back of the patient at around T3 location (Figure 1). This accelerometer was selected because of the low power consumption, small size and high accuracy. The resolution of the accelerometer was 1.5 degrees over a full range (0 - 90 degrees). The microcomputer unit consists of a microcontroller, memory with associated circuitry and a battery pack. The whole unit was packaged into a box (Figure 2) with dimensions of 5.5cm x 8.0cm x 2cm and its weight was approximately 25g. Subjects carried the system with a belt clip during this study. The system requires recharging everyday for a maximum 2 hours. 0 is the angle measured from the accelerometer.

Figure 1. Sagital view of the accelerometer location.

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Figure 2. The microcomputer unit.

In laboratory testing, measurements were taken at 2 samples per second for 10 seconds in each of four postures (standing, forward and backward bending, and repeated standing). The repeated standing was used to detect any movement of the accelerometer after activites. Digital images were captured at each of the positions (Figure 3). To test the accuracy of the Spine-Straight device, an image with a laser scanner (Minolta 700) was taken with the accelerometer in place. Software written in MATLAB was used to calculate the kyphosis. Two volunteers used the system for 2 days trial during their normal daily activities. On the first day, no feedback was provided. Feedback was provided on the second day while the measured angle was more than the personalized threshold value. Feedback was in the form of buzzer (similar to a pager) emitting a vibration for two seconds. For this study, the threshold was set 5° higher than normal standing. The sample rate was set at one sample per minute. The sampling rate was adjustable under software control and was set at a level that was not too frequent as to cause annoyance but often enough to make the subjects aware of their posture. Both subjects used the system more than 6 hours per day. 5. Results The accuracy as measured during calibration in a laboratory setting of the laser scanner system and the accelerometer for the angle measurement were ±1° and ±1.5°, respectively. In laboratory measurements, the angles measured from the accelerometer on subject 2 at the three postures, standing, bend forward and bend backward, were 15±0.7°, 52±0.5° and 5±0.7°, respectively. The repeated standing measurement was 15±0.4°. The

Figure 3. The back images of the three postures.

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angles from the laser scanner system at the same postures were 15.5°, 53.5° and 5°, respectively. The maximum angle deviation between the laser scanner system and the SpineStaight device was 1.5 degrees. On the 2 day trial, the average angle 0 on day 1 and day 2 during normal daily activities were 63116° and 72±15° for subject 1, and 68±21° and 76±14° for subject 2. Both subjects used the system while they did their routine work during the day. No specific activities or movements were recommended. Subjects were asked to respond to the feedback on the second day. Figure 4 (a) and (b) shows the frequency distribution of the angle measurements of subjects 1 and 2, respectively.

6. Discussion and Conclusions For the 2 day trial, subject 1 reported that he was standing more often than sitting during both days; however, subject 2 was sitting more often than standing. Also, they both reported that they tried to respond to the feedback as many as possible. The change of the angle 9 was more significant on subject 1 than subject 2. This might be due to the subject 1 has a bigger kyphotic angle than subject 2. Both subjects commented that the system was light, easy to carry and un-obtrusive. From both results, we found that the average value of angle 9 was smaller on the second day than on the first day. This might be due to both subjects straightening their spines more often. This preliminary study illustrated that the system was able to detect the change of subjects' postures, and may help subjects to improve their postures if they respond to the feedback. Reference Detroit Medical Center: Definition of Kyphosis. [Patient Information web site]. Available at http://www.dmc.org/health info/topics/bone3433.html Accessed since 1998.

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Study of vertebral morphology in Scheuermann's kyphosis before and after treatment E. Pola, S. Lupparelli*, A.G. Aulisa, G. Mastantuoni, O. Mazza, V. De Santis Clin. Orthop. Pol. A. Gemelli - Universit_ Cattolica del Sacro Cuore, Roma, ITALY * Centra Orthopedico Umbro, Perugia, ITALY Abstract Variation of vertebral morphology in Scheuermann's Kyphosis before and after orthopedic treatment is usually measured by the entity of the curve, using Cobb's method, and by vertebral wedging. But the lack of correlation between these parameters and the clinical evolution of the deformity , lead to the possibility of other alterations that can explain part of the kyphosis deformities before and after the treatment. In this group of alterations the inclination of anterior and posterior walls, that express the trapezoid deformity of vertebras, seem to be more reliable indicators of curve response to ortopedic treatment.

1. Introduction In 1920 Scheuermann [1] first described the association of developmental Kyphosis and wedging of thoracic vertebrae; he used the term "osteochondritis juvenilis dorsi" [2], but the condition is universally known today as Sheuermann's kyphosis. Sorenson [3], proposed a diagnosis based on the presence of three or more adjacent vertebrae wedged 5° or more and no evidence of congenital, infectious or traumatic disorders of the spine. These criteria are widely accepted and used today. Vertebral geometry alterations in Scheuermann's kyphosis and results of the orthopedic treatment have been measured by radiographic measure of both curve entity and vertebral wedging on longitudinal section [4,5,6,7,8]. Clinical evolution of the deformity is not always correlated to presently used radiographic parameters. On the other hand, it is possible that vertebal morphology alteration in kyphotic curve could be explained by a more complex theory model than the currently accepted one. In this case currently used radiographic parameters could be insufficient for the evaluation of entity, progression and response to medical treatment. We have made a revision of our cases in order to define present parameters limits and, at the same time, to determine new parameters, which could be useful for a better correlation between clinical and radiographical findings and a better description of vertebral alterations. 2. Materials and Methods We made a retrospective study on a specimen of 16 patients with Scheuermann's kyphosis, treated using anti-gravity brace between 1996 and 2000, at Agostino Gemelli Hospital, department of Orthopaedics, Rome, Italy. 90% of our patients is male, 10% female.

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The mean age at the beginning of the treatment was 13 years. All patients had the same bone maturity grade, determined by Bick's method [9,10]. The mean curve entity before treatment , measured by Cobb's method, was 54,5°, a value that, according to literature data, requires orthopaedic treatment [11]. Radiographical measurement were performed on radiographs taken from a focal distance of 2 meters, on radiographic film 36x91 cm, from a lateral projection, at the beginning and at the end of the treatment. Vertebral geometry modifications before and after treatment were analysed according to the following parameters, evaluated by three independent researchers: - Anterior wedging angle (ALFA) Anterior wall inclination (AANT) - Posterior wall inclination (APOS) Anterior wedging angle ALFA has been calculated by two methods (figure la and Ib). The first method, used in the measurement of small deformities, is the calculation of the convex angle obtained by the intersection of two lines, orthogonal to both of the two lines passing through the extremities of superior and inferior vertebral body limits. The second method, used in the measurement of severe deformities, is the calculation of the convex angle formed by both of the two lines passing through the vertebral plates. The degree of inclination of the anterior wall (AANT) and posterior wall APOS has been measured by the disk limit of every vertebral body (figure 2). Specifically, we measured the angles formed by the line orthogonal to the inferior plate and the line passing trough inferior and superior limits of the anterior and posterior wall. Study of the variation of these three parameters (ALFA, AANT, APOS) before and after orthopaedic treatment was conducted in two phases. During first phase modification of both parameters was analysed with the confrontation of pre- and post-treatment vertebral values, not considering the vertebra position in the kyphotic curve. During the second phase we analysed data dividing vertebras in sub-groups, or sectors, in relationship to their position in the curve. Inclusion of the vertebras in a defined sector followed these criteria: apex vertebra received, conventionally, value 4; upper vertebra received value 3, and lower vertebra value 5. Vertebras positioned at highest and lowest limits of the kyphotic curve received, respectively, value 2 and 6. We took L2 as control vertebra, and gave it value 1. 3. Statistics Measurement variability among observers has been analysed by the Bland-Altman test. The absence of a significant variability among measurements performed by three independent observers enabled us to use, in the statistic elaboration, the mean value of three measurements, taking into consideration every parameter. We used the Shapiro-Wilk test in the evaluation of the gaussian distribution of the pre-treatment ALFA, AANT and APOS values. This evaluation was necessary, as we were analysing a specimen not selected from general population through a random process, and because it could not satisfy central limit teorema. Test signification (P8), as represented in figure Ib and Ic.

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2.3 Mechanical personalization In a first step material properties of vertebrae, disks and posterior elements were introduced from in vitro experiments ^. Preoperative clinical bending tests were used to assess specific mechanical characteristics of the patient. These tests were simulated in the following way: Tl and pelvis displacements (measured on Xrays) were introduced as boundary conditions in the model, and difference was quantified between spine configuration yielded by the model and that measured on Xrays in bending Mechanical characteristics of soft tissues were then adapted locally or regionally [sl until the error between simulation and radiographic measurement tend to 5° for the vertebrae orientation and 10 mm for the body line. 2.4 Simulation of surgical correction To mimic the surgical procedure of correction the five steps of surgery*21 were defined as follow: • Surgical preparation: Under anesthesia, in ventral decubitus, the patient is fixed under traction, vertebrae within the instrumented area were then exposed and the surgeon proceeded to an articular facets resection. To simulate this resection, contact elements and capsular ligaments of the instrumented area were deleted. The traction was simulated as a displacement of CO along the axis imposed by the table's geometry. • Hooks placement and rod geometry: This second step needed no calculation. Hooks of the concave side were modeled using an elastic beam. • Distraction: During the surgery, the first rod was firstly inserted in extreme hooks or screw, then the spine was pushed toward the rod until the rod was hooked. To simulate this step of distraction, for each intermediate hook (from bottom to top), its posterior node was displaced toward the rod. • Rod derotation: During the surgery, the first rod was rotated toward the concave side of about 90 °. For the simulation, the link between the rod and the hook or the screw was represented by a sliding pivot. A local axis was defined by the two end nodes of the rod, the concave rod was rotated of 90 ° around his local axis. • Hooking the second rod: finally, the second rod was hooked on the convex side of the scoliotic curve and transverse mechanisms of fixation were fixed.

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V7. La fage er at. / Finite Element Simulation i>f Various Strategies for CD Correction

2.5 Simulation of alternative surgical strategies To analyze the effects of the alternative surgical strategy, surgeon asked us to simulate the surgery correction with various choices of end vertebrae: • Case 2: lower claw in L1-L2 (figure 2) instead of Tl 2-L1 • Case 3: two hooks in L1 instead of a claw (figure 2) • Case 4: upper claw in T4 (figure 2) instead of T5 One may notice that case 3 represented the strategy used at the earlier times of the CD correction.

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2.6 Validation The results of the bending test simulations were compared to the measurements extracted from the lateral bending films in terms of vertebral body line and vertebrae orientation. As for the surgery simulation, results were compared with the post-operative 3D reconstruction obtained using stereoradiography. 3. Results and discussion 3.1 Mechanical Personalization For the posterior ligaments and for the disk stiffness in torsion, we found no differences between this specific patient and a normal one. As for the stiffness in bending, we found 2 areas (T1-T7 and T12-L3) much stiffer than in the standard model. These qualitative results were in adequation with the surgeon analysis to appreciate the reducibility of the scoliotic curve. For the vertebra body line in the frontal plane, this mechanical personalization allowed to reduce mean errors from 11.3mm (max 25mm) to 4.3 mm (max 10mm). The same phenomena were obtained for the vertebrae orientations: mean errors of vertebrae axial rotations were reduced from 10.9° (max 25°) to 2.1° (max 5°) and mean errors of vertebrae lateral bending from 5.1° (max 15°) to 2.3° (max 5°).

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3.2 Surgical Simulation Simulation results were compared with the post-operative 3D reconstruction. For the vertebral body line (figure 3), mean errors were 3.9 mm (max 5mm) in the sagittal plane and 4.1 mm (max 8 mm) in the frontal plane. As for the vertebrae orientation (figure 4), mean errors were 2.3° (max 4.8°) for the axial rotation and 2.1° (max 4.9° )for the lateral bending. Differences between the simulated surgery and the real one may be due in part to an excessive simulated correction: the frontal balance was better in the simulated case as well as the correction of the vertebrae axial rotation. The maximal error in axial rotation (in T12) was localized on the lower claw (T12-L1) : the hook mechanical action may need to be better modeled. Axial Rotation Sagittal plane

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3.3 Simulation of alternative surgical strategies In this preliminary study, results were analyze qualitatively. • Case 2 yielded excessive vertebrae axial rotation and frontal imbalance • Case 3 improved slightly the frontal balance • Case 4 yielded a slight frontal imbalance and a significant sagittal imbalance These first results allowed the expert surgeon to confirm his intuition and may indicate that either strategy corresponding to case 1 or to case 3 could have been considered. 4. Conclusion The results of this preliminary study are relevant for two reasons. First, it demonstrated that a finite element model can simulate the specifc mechanical behavior of a given patient. To do this, the model must be personalized not only geometrically but also mechanically. Secondly, the coherence between the simulations and the post-operative 3D

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reconstruction proves the feasibility of this finite element modeling approach as a qualitative and quantitative predictive tool of correction. As for the alternatives strategies, we didn't found in literature any reference on the effect of the surgical strategy. Nevertheless the model prediction was coherent with surgeon feeling. After extensive validation, the model should constitute an invaluable predictive tool for surgery planning. 5. Acknowledgements The geometry of the model was developed in collaboration with the Laboratoire de recherche en Imagerie et Orthopedic (LIO) of Pr J. de Guise (ETS, Montreal, Canada). References 1. 2. 3. 4. 5. 6 7. 8 9.

Cotrel Y, Dubousset J, Guillaumat M. New universal instrumentation in spinal surgery. Clin Orthop 1988;227:10-23. Dubousset J, Cotrel Y. Application technique of Cotrel-Dubousset instrumentation for scoliosis deformities. Clin Orthop 1991:103-10. Le Borgne P, Skalli W, Lecire C, Dubousset J, Zeller R, Lavaste F. Simulation of CD Surgery on a personalized Finite Element Model : Preliminary results. 4th International Symposium on three dimensional scoliotic deformities. Vermont, USA, 1998. Mitton D, Landry C, Veron S, Skalli W, Lavaste F, De Guise JA. 3D reconstruction method from biplanar radiography using non-stereocorresponding points and elastic deformable meshes. Med Biol Eng Comput 2000:38:133-9. Le Borgne P, Skalli W, Dubousset J, Dansereau J, Zeller R, Lavaste, F. Finite Element Model of scoliotic spine: Mechanical Personalization. 4th International Symposium on three dimensional scoliotic deformities. Vermont, USA, 1998. Stokes IA, Bigalow LC, Moreland MS. Three-dimensional spinal curvature in idiopathic scoliosis. J Orthop Res 1987;5:102-13. Descrimes JL. Modelisation par elements finis du rachis et de la cage thoracique pour I'etude des deformations scoliotiques. PhD Thesis, 199S Ecole Nationale Supdrieure des Arts et Metiers Le Borgne P. Modelisation par elements finis de la correction chirurgicale de la scoliose par instrumention Cotrel-Dubousset. PhD Thesis, 1998 Ecole Nationale Superieure des Arts et Metiers Koubaa W. Modelisation geometrique et mecanique tridimensionnelle par elements finis du rachis thoracique. PhD Thesis, 1995 Ecole Nationale Superieure des Arts et Mftiers

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Idiopathic Scoliosis. Segmental Fusion With Transpedicular Screws A.Christodoulou2,A.Ploumis2,C.Zidrou1, J.Terzidis2, J.Pournaras1 1. A' Orthopaedic Department of Aristotelian University ofThessaloniki 2. Orthopaedic Department of Hippokration General Hospital ofThessaloniki Abstract. The purpose of this study is to evaluate whether the surgical correction of the scoliotic curve with the use of segmental pedicle screw fixation system is effective. We studied 20 patients (19 girls, 1 boy) with a mean age of 14,6 years (range from 13 to 22). The spinal deformities were evaluated by Cobb method with anteroposterior and lateral bending radiographs. There were 13 right thoracic curves and 7 left thoracolumbar curves. The width of the pedicles was estimated in all patients by computerized tomography of the thoracic and lumbar spine. Posterior instrumentation (Moss-Miami transpedicular system) was used and additional thoracoplasty was performed in 2 patients. The transpedicular screws were placed between T2 and L5. Intraoperatively the image intensification was indispensable and the wakeup test was always conducted. All the patients were assessed both clinically and radiographically at 3,6,9,12 months and annually until now. The average follow-up was two years. There was an average correction of 73% of the primary curve (pre-op standing average 59° (range from 42° to 87°), lateral bending average 33° (range from 10° to 75°), post-op average 13° (range from 6° to 30°), at last examination average 14° (range from 6° to 33°). Infection and neurological complications were not noted. No major complications were observed. Exact evaluation of the pedicles by CT scan is an essential prerequisite for transpedicular screw insertion. The correction of idiopathic curves with the use of segmental pedicle screw fixation system is a very effective method(correction > 70%) It seems that control of the three columns of the spine by the transpedicular screws offers sufficient apical translation and coronal realignment.

1. Introduction The surgical correction of scoliosis in adolescence remains a last resort treatment. This is usually performed when there is a significant curve (>40°) or a rapidly progressive curve. The aim of such surgical correction has many facets. The first one is to stop the irremediable progression of the angulation of scoliosis. The second one is to obtain through a surgical technique the reequilibrium of the curves in the frontal and sagittal planes and also to obtain derotations of the vertebrae. The final aim is to obtain the correction of the structural deformity. To obtain these results different surgical methods were developed in the 1950s. Until the 1980s the Harrington rod procedure was considered the gold standard. Through a simple posterior surgical approach, this instrumentation had advantages, like rapidity of application. The main disadvantages of the Harrington procedure are a fragile construction, neurologic risks by distraction, difficulties in restoration of the sagittal plane curves and the requirement of postoperative cast support for a significant period. Hook insertion techniques are standard, familiar and generally accepted. However, hook displacement may occur during curve reduction maneuvers. By definition all hooks intrude the spinal canal and may be associated with neurologic complications.

Pedicle screw fixation in the lumbar spine has received widespread acceptance in the treatment of fractures and degenerative conditions, but there has been less documentation of it for the treatment of AIS15. In theory, pedicle screw fixation offers more stable fixation in the lumbar spine with the possibility of better correction over a shorter segment9 while remaining completely external to the canal. Screws inserted through the three columns of the spine, are inherently stable and resist loads in all planes, thus offering a potential advantage in comparison with hooks. Although accurate pedicle screw insertion may present problems, numerous authors report a low complication rate and a better three-dimensional correction as well as a shorter fusion length and less loss of correction in comparison to hook fixation2'3'46'78'1112 Thoracic pedicle screw instrumentation , is sometimes regarded as having a higher risk of serious neurologic injury10. Suk et al12 published 15 cases of exclusively pedicle screw instrumented idiopathic scoliosis with fusion extending to the thoracic spine. Based on increasing experience with pedicle screw instrumentation in scoliosis surgery, the authors of the present study have extended its application from the lumbar to the thoracic spine. The purpose of this study is to evaluate whether the surgical correction of the scoliotic curve with the use of segmental pedicle screw fixation system is effective. 2. Material and Method Twenty patients with adolescent idiopathic scoliosis who were operated on by the senior author during the period 1998-2000 were included in this study. They were 19 females and one male with a mean age at the time of surgery of 14,6 years (range, 13-22). The curves appeared to be right thoracic in 13 patients and left thoracolumbar in 7. The preoperative assessment included apart from the routine blood tests and ECG studie^poster^anterior and lateral films with the patients standing as well as posteroanterior films in lateral bending positions for evaluation of the reducibility of the curves. The cobb method was used to measure the angles of the curves (fig.2). Evaluation of the vertebral rotation with the Perdiolle method was intended to be performed initially, but the frequent postoperative implant shadow covering of the pedicles made it impossible. The width of the pedicles was estimated in all patients by computerized tomography of the thoracic and lumbar spine (fig. 1). MRI was performed in all patients for diagnosis of spinal dysraphism. Posterior instrumentation (Moss-Miami transpedicular system) was used in all patients. An additional thoracoplasty was performed in 2 of them. The Moss-Miami is a universal spinal instrumentation system consisting of a titanium 5,5 mm solid rod, hooks and pedicle screws of different lengths and diameters. The screw rod interface is fixed by double (inner and outer) nuts. The principles of Cotrel et all5 were followed for curve correction by rod rotation and slight distraction on the concave side and compression when this was necessary on the concave side. Through a posterior approach, the chosen levels were prepared and visualized. The point of introduction of the pedicle screw was defined by the transaction between the horizontal line of the transverse process level and the vertical line passing through the articular facet. The convergence of the introduction pin was depended on the rotation of the scoliotic vertebra, and was parallel to the upper plateau of it. First, the pedicle was entered and widened with an awl, and the pedicular cavity was explored with a sounder to verify an intact medial, lateral.

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superior and inferior cortex. After screw insertion, the correct placement and length was confirmed with intraoperative fluoroscopy in both planes. Facet resections were performed to give mobility and enhance the fusion. Posterior element decortication was performed at the end of instrumentation to decrease blood loss, and then autologous bone grafts were inserted. Intraoperatively the wake-up test was conducted. Suction drain was used in none of the patients. A peridural catheter was placed through the ligamentum flavum of the first free intervertebral space. The peridural catheter was left in place for an average of two days after surgery. Pain control was obtained with morphine solutions. All blood transfusions were done by autotransfusions of predonated blood apart from two patients. The patients began walking without brace protection during the first 5 postoperative days. All the patients were assessed both clinically and radiologically at 3,6,9,12 months and annually until today. The results were analyzed by comparing the pre and post-operative radiographs regarding the curve measurements and the balance of the spine 3. Results The primary curves measured 42° - 87°, (average 59°) on the standing films and 10°75° (average 33°) on the lateral bending films preoperatively. These curves were corrected to 6° - 30° (average 13°) postoperatively (fig.3) (73,4% correction). At the last follow up (average two years) the average curve was 14° (range 6° - 33°). Screws of 5 mm diameter were inserted in the thoracic spine with exception at T4 T5 T6 levels in which the 4,35 mm screws were used (paediatric instrumentation set). 5mm or 6mm screw were inserted in the lumbar spine. Transpedicular screws were placed between T2 and L5 in this series of patients. No major complication such as abnormal neurologic signs or infection were noted. The patients were free of pain and fatigue and had satisfactory cosmetic result with balance spine. Cases of screw dislocation or rod breakage were not noted. Complications related to the pedicle screw placement were not observed either. All the patients were transfused with autologous blood except for two. In those patients two blood units for each of them were necessary in addition to the predonated three blood units. 4. Discussion Pedicle screws are used with increasing frequency for fixation in spinal fractures and instrumentation for degenerative spinal disorders. Their widespread use stems from the idea that pedicle screws provide better fixation and potential control of the coronal and sagittal planes than hooks and wires and require no reliance on distraction or compression. Screws achieve fixation by a means completely external to the spinal canal. Achievement of a solid spinal fusion continues to be the most important measure of success in spinal deformity surgery. Fixation for adolescent idiopathic scoliosis has continued

4?6

to evolve from cast fixation, to nonsegmental rods, to segmental sublaminar or spinous process wire fixation with nonsegmental hooks. The series by Suk et al12 and Hamill et al6 suggest the routine use of pedicle screws in the lumbar spine. The availability of pedicle screws begs the question of whether they become part of the standard instrumentation for adolescent idiopathic scoliosis. Evolution of prevalent instrumentation techniques for AIS has reflected not only the availability of these techniques but also the pursuit of a set of evolving goals. Solid fusion remains paramount, but enhanced correction of coronal and sagittal plane deformity has become a goal of spinal instrumentation. Better, more aggressive fixation, is also used in the name of instrumenting fewer levels, leaving potentially more mobility below the fusion mass. It is clear that segmental multihook contourable rod fixation has improved the attainment of these goals. Pedicle screw instrumentation of the lumbar curve may enhance the improvements achieved by multihook segmental fixation. Thus , it would seem clear that enhanced coronal plane correction can be attributed to the use of pedicle screws in the lumbar spine. Enhanced fixation is a presumed benefit of pedicle screws. Thus the theoretical benefit of enhanced fixation seems to be reflected in less loss of correction at follow-up which was observed in this series (average loss 1 °). Theoretically, enhanced fixation in the sagittal and coronal planes with pedicle screws would enable enhanced correction of rotational deformity in lumbar curves when pedicle screws are used at every pedicle and every level. The safety of pedicle screws has been questioned and discussed extensively. In theory, screws placed in the pedicle are safer than hooks or wires which must pass into the spinal canal. The most important features of the currently reported operative technique include application of forced translation to the apical vertebra into an overcorrected position. In addition, distinctive force is applied to the concave pedicle screw on the end vertebra. The current authors have not found pedicle screws in every vertebra necessary, nor have they found substantial compressive force along the rod on the convexity helpful. Measurement of the transverse pedicle width preoperatively is very essential when using traspendicular screw-rod systems for correction of idiopathic scoliosis. In the plain films these measurements are impossible. Weinstein et al13 and Whitecloud et al14 demonstrated that a roengenogram-based assessment using traditional anteroposterior and lateral views even for implanted pedicle screws resulted in an unacceptably high rate of false-positive and false-negative evaluations. As computed tomography scans have shown to provide a reliable assessment of pedicle screw placement. With the same method evaluation of the pedicles mainly of the apical and end vertebrae was carried out pre-operatively in this series. The results of this evaluation lead us to the use of paediatric screws (4,35mm) in certain thoracic levels. Pedicle screw instrumentation in scoliosis surgery is gaining in popularity because of its higher immediate rigidity , better correction and shorter fusion length. Several authors have reported on the neurologic hazards of pedicle screw instrumentation of the lumbar spine. Mulholland 10 attributed a greater risk of serious neural injury to thoracic pedicle screw placement than to lumbar pedicle screw instrumentation. Medial penetration is certainly the most feared screw misplacement because spinal canal encroachment may lead to spinal cord injury. Liljenqvist et al7 pointed out the direct contact between the pleural lining of the thoracic cavity and the inferolateral wall of the pedicle. A lateral screw penetration thus may endanger the lung or segmental vessels. Neither spinal cord injury nor segmental vessel trauma was noted in this.series.

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Predonation of autologous blood has been proved a safe method of intra and post operative blood transfusion in this series. All the disadvantages of homologous transfusion were avoided especially in the young population involved in spinal surgery. The correction of idiopathic curves with the use of segmental pedicle screw fixation system is a very effective method (correction>70%). Pedicle screws appear safe and are associated with a statistically greater curve correction, maintenance of correction, and improvement in the uninstrumented vertebral segments below the fusion. It seems that control of the three columns of the spine by the transpedicular screws offers better apical translation and coronal realignment. Despite of them, pedicle screw placement in the thoracic spine scoliosis surgery requires meticulous caution and considerable experience because of the limited applicability of the originally described landmarks of screw insertion to a scoliotic spine and because of the confined dimensions of the thoracic pedicles. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

14. 15.

Aebi M., Thalgoff J. S, Webb J.K. Scoliosis: Posterior correction and Stabilization. In AO ASIF principles in spine surgery p. 158 Springer Verlag 1998. Barr SJ, Schuette AM, Emans JB. Lumbar pedicle screws versus hooks. Spine 1997;22:1369-79 u66s N, Webb JK. Pedicle screw fixation in spinal disorders:a European view. Eur Spine J 1997;6:2-18. urown CA, Lenke LG, Bridwell KH, Geideman WM, Hasan SA, Blanke K. Complications of paediatric thoracolumbar and lumbar pedicle screws. Spine 1998;23:1566-71. Cortel Y, Dubousset J, Guillanmat M. New universal instrumentation in spinal surgery. Clin. Orthop 1988;229:10-23 Hamill CL, Lenke LG, Bridwell KH, Champan MP, Blanke K, Baldus C. The use of pedicle screw fixation to improve correction in the lumbar spine of patients with idiopathic scoliosis. Is it wanted? Spine 1996;21:1241-9. Liljenqvist U, Halm H, Link Th. Pedicle screw instrumentation of the thoracic spine in idiopathic scoliosis. Spine 1997;22:2239-45. Liljenqvist U. Vertebral morphology in idiopathic scoliosis. Didactic Session 1-7. Monney G. MD, Kaelin A. MD. Short posterior fusion for patients with thoracolumbar idiopathic scoliosis. Clin. Orthop. and Related Research, 364,32-39. Mulholland RC. Editorial:Pedic!e screw fixation in the spine. J. Bone Joint Surg [Br] 1994;76:517-9. Suk SI, Lee CK, Kim W, Chung Y, Park Y. Segmental pedicle screw fixation in the treatment of thoracic idiopathic scoliosis. Spine 1995;20:1399-1405. Suk SI, Lee CK, Min HI, Cho KH, Oh JH. Comparison of Cotrel-Dubousset pedicle screws and hooks in the treatment of idiopathic scoliosis. Int Orthop 1994;18:341-6. Weinstein JN, Spratt KF, Spengler D, Brick C, Reid S. Spinal pedicle fixation: Reliability and validity of roentgenogram-based assessment and surgical factors on successful screw placement. Spine 1998;13:1012-8. Whitecloud TS HI, Butler JC, Cohen JL, Candelora PD. Complications with variable spinal plating system. Spine 1989;14:472-6. Zindrick MR. Pedicle screw fixation. In Weinstein SL, ed. The Paediatric Spine: Principles and Practice. New York: Raven Press, 1994:1683-715.

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Spinal Surgery Procedure Discretization F. Verniest"23), D. Chopin (4), A-P.Godillon-Maquinghen (l)

Res. Cent., S-Justine Hospital, 3175 Cote Ste-Catherine, H3T1C5, Montreal, Canada Biomed. Eng. Inst., Ecole Polytechnique de Montreal, Montreal H3C 3A7, Canada LAMIH, Universite de Valenciennes, 59313 Valenciennes Cedex 9, France Institut Calot, 62608 Berck sur Mer Cedex, France

I2>

Abstract: In the last decades, scientists developed analytic models of spinal surgery to assess surgical choices and instrumentation parameters. They noted the difficulty to represent the boundary conditions on their deterministic models and recognize the lack of knowledge in surgical procedures. This paper presents a formalization technique applied to spinal surgery to improve the formulation of biomechanical models. This technique consisted into two steps: knowledge extraction and knowledge representation. The protocol was established with an expert surgeon using Colorado2 instrumentation. Surgeon's knowledge acquisition has permitted to define eleven detailed independent data cards for the different steps of surgery like hook or screw insertion, rod installation, etc... The behaviour of the concerned elements on its neighbouring entity were specified using three matrices. The link between surgery and modelling becomes easier and permits to better define the boundary conditions on each entity during the simulation.

1.

Introduction

Over the past two decades, new advancing in surgical strategies to spinal deformities treatment and instrumentation systems have been realized [1]. To assess surgical choices and instrumentation parameters, scientists have developed 3D analytic models simulating surgical procedure [2-4] by simplifying it into two or three stages. Their representation of surgical acts is based on the general principles of the instrumentation technique, and is not personalized to the surgeon's experience and knowhow. Stokes et al. [5] note that the segmental instrumentation offers surgeons many variables and multistep maneuvers to adapt to individual patient's needs. But it conversely creates many unknowns for the biomechanical analyses (boundary conditions, number of stages, applied forces), and difficulties in validation of model predictions. They conclude that to help surgeon in the elaboration of his surgical planning, deterministic modeling of scoliosis surgery requires more information to formulate the models, better specifications of inputs and improved analysis tools. To this end, we propose to use techniques of artificial intelligence (AJ).The purpose of this paper is to present the mechanical formalization of surgical acts for scoliosis surgery from the know-how and knowledge of an expert surgeon using Colorado2 instrumentation. 2.

Methods

The surgeon expert technique is empirical and implies many conflicted variables and objectives that require an elaborate knowledge extraction. It is decomposed into two steps: knowledge extraction and knowledge representation.

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Knowledge Extraction It is based on IA techniques [6-10]. The first part of our protocol is to extract the expert's generalized knowledge. During interviews with the surgeon, a specific questionnaire related to specific cases is submitted. It permits to identify several variables that the surgeon is using during surgery and to evaluate their importance. To complete and refine the expert acquisition knowledge, the second part of the protocol was established during expert's activities. 20 surgical interventions of scoliosis were directly observed. These clinical cases were operated by the same expert surgeon. They were 18 females and 2 males. The mean age was 19 years. Each patient has idiopathic scoliosis pathology. All surgical procedures were applied by a posterior approach using Colorado2 instrumentation. Four stages were considered. Stage 1: Before beginning the surgery, the knowledge engineer with the surgeon analyse the clinical and geometrical data of the patient. The surgeon exposes his operative strategy and explains his choices. Stage 2: During surgery, the surgeon describes and explains each maneuver (implant insertion, deformation of rod, installation of rods,...). Stage 3: At the end of surgical intervention, the result of surgery is analyzed. Obscure points are discussed Stage 4: To validate expert's data collected during the other stages, and to finalize the knowledge extraction, it needs to confront the expert to his results. A few days later, using per-operative data, the specific strategy of the surgery is discussed and compared with operative strategy of similar cases operated by the same expert surgeon. Knowledge Representation The process is established from the decomposition of knowledge extraction analysis into two independents frames. The first steps consist to identify the different entities and surgical maneuvers of the surgery. Variables that appear clinically important to the surgeon and subjectively significant to the knowledge engineer, are classified and encoded. The scheme OBJECT-ATTRIBUTE-VALUE is affected to each variable and is inferred into IFTHEN rules[6]. This analysis permits to decompose the expert approach into standard leading facts. To each fact corresponds a card that contains a very detailed description of associated surgical act, geometrical and mechanical data of entities requested, representation analysis results [9]. The second frame consists to sequence the different surgical acts and associated variables to define the global procedure based on adapted constrained planning. Villeneuve et al. [11] propose to sequence the different tasks in tables, matrices or "deciding tree". Our choice is to organize different surgical acts through matrices. Each matrix specifies the behaviour of the concerned element on its neighbouring entity. 3.

Results

The different meeting between the expert surgeon and the knowledge engineer corresponded to eighty hours of interviews and analysis on two years. The expert's knowledge extraction permitted to define ten independent data cards : 1.- Patient Positioning ; 2.- Instrumented Zone Preparation ; 3.- Closed Laminar Hook Insertion ; 4.- Pedicular Hook Insertion ; 5.- Pedicle-Laminar clip ; 6.- Pedicular Screw Insertion ; 7.-Inter Pedicular Plate Positioning ; 8.- Fusion Preparation ; 9.- Rod Bending ; 10.- Clip insertion ; and one card corresponding to global surgical procedure: sequencing of surgical acts. To resume the sequence of activation and deactivation of joints or forces, the global surgical procedure was defined into three matrices: convex rod installation, concave rod

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installation, reduction by translation of the spine on the rods. Each matrix specifies the behaviour of the concerned element on its neighbouring entity. In application, the formalized data have been encoded into ADAMS software to formulate the mechanical model, using Poulin et al.[2] approach, to simulate the surgical procedure of a clinical case. The model is in respect with real surgical acts sequence and permitted to simulate independents actions like the translation of clip through rod, translation of clip to screw or hook, translation of nuts to mooring points, or rod adjustments. The figure 1 illustrates the configuration of the model at different steps.

Figure 1: Rods insertion on spine 4.

Discussion

The results of this study show the possibility to represent the link between the kinetics approach and the scoliosis surgery by the redaction of ten data cards describing the surgical actions and proposing associated biomechanical formalization and representation, and by three matrices sequencing all surgical actions. These results reflect a very detailed description and a more precise mechanical representation of different mechanical variables of scoliosis surgery as compared to precedent studies [2, 3]. The analysis of scoliosis surgery in our study is qualitative. But our method was allowed to identify most variables and steps of scoliosis surgery to improve the associated mechanical representation. In application a model using multi-body approach was generated and permitted to simulate all identified independent surgical acts of scoliosis surgery. Specific expert's information are not easily extracted because of the number and of the difficulty to analyze the interaction between them. To this end, we have proposed to use the IA techniques. This work was established about techniques of knowledge analysis, used in different domain like conception of aided process in fabrication or assembly to sequence machining operations [11] or in development of expert system flight monitor [12], and recently in scoliosis research [10]. The feasibility to use these techniques in scoliosis surgery modeling is now shown. However this protocol needs a large investment of the knowledge engineer and the surgeon. The small number of clinical cases and the planning of each associated surgery during the year is an important parameter to evaluate the expertise time. Quality of its analysis depends on many parameter: localization of protocol applications and meetings, personal investment of each actor, data treatment, number of clinical cases. The second stage of our protocol is in respect with the expectations defined by Fadier et al [13] who advise to realize the knowledge formalization from expert's work localization.

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This knowledge extraction is performed with only one expert surgeon, and the results are personalized to his know-how. We precise that a realization of a "universal" mechanical formalization of surgical acts could impose a muti-expert knowledge extraction that seems empirical in the scoliosis surgery domain using these formalization techniques. 5.

Conclusion

We have shown the feasibility to identify many surgical variables and parameters using the AI techniques. From these formalized data the biomechanical formulation of models is more complete and permits a great flexibility in the simulation of different surgical acts. The simulation of scoliosis surgery can now be personalized to patient's procedure and to the surgeon's know-how. The surgeon can now find in biomechanical model all surgical acts that they realized during surgery and can validate the modeling approach. 6. Acknowledgements CRNSG (Canada), FCAR (Canada), and MESR (France), Consulat de France (Quebec) References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

12.

13.

Chopin D., Advances in the Surgical Treatment of Scoliosis. European Instructional Course Lecture, 1997. 3: p. 173-180. Poulin F., et al., Modelisation Biomecanique de I'Instrumentation du rachis Scoliotique a I'aide de Mecanismes Flexibles: Etude de Faisabttite. Annales de Chirurgie, 1998. 52: p. 761-767. Aubin C-E., Finite Element Analysis for the Biomechanical Study of Scoliosis. Spine, 2000. 14(2): p. 489-504. Verniest F., et al., Biomechanical Simulation of Colorado Instrumentation of the Scoliotic Spine: Preliminary Results, in IRSSD 2000. 2000. Stokes I.A.F., et al., Biomechanical Simulations for Planning of Scoliosis Surgery, in Research into Spinal Deformities 2,1.A.F.S. Ed., Editor. 1999, IDS Press, p. 343-350. Olson J. R. and Rueter H. H., Extracting Expertise from Experts: Methods for Knowledge Acquisition. Expert Systems, 1987.4: p. 152-167. Boy G., Acquisition des connaissances, in Assistance a I'operateur : une approche de I'intelligence artiflcielle, Teknea, Editor. 1988. Benkirane M., et al. Aspects de la Psychologic Cognitive dans I'acquisition des connaissances. in Actes de la 2eme Conference Europeenne et les Applications de VIA en milieu industriel et de service. 1990. Anselmetti A. and Villeneuve F., Computer Aided Process Planning : two ways for inclunding a user's know-how. Manufacturing Systems, 1992.21: p. 167-172. Chusseau S., Systeme d'aide a la decision pre-operatoire en chimrgie orthopedique de la scoliose, in These en Automatique Industrielle et Humaine. 1999, Univerist£ de Valenciennes et du Hainaut Cambr&is: Valenciennes. Villeneuve F. and Sabourin L. Machining Features, Production Rules and Constraint Programming, Keys for a Capp System, in Proceedings of the 2nd International Conference on Industrial Automation. 1995. Disbrow J.D., Duke E.L., and Regenie V.A. Development of Knowledge Acquisition Tool for an Expert System Fligth Status Monitor, Technical Memorandum, in AIAA 24th Aerospace Sciences Meeting. 1986. Reno, Nevada. Fadier E., et al., Valorisation du Retour d'Experience - dossier Retour d'experience. Performances Humaines et Techniques, 1994. 69: p. 34-37.

Th.B. Gri\as(Ed.t Research into Spinal Deformities 4 IDS Press. 22

Surgical treatment of scoliosis in myelomeningocele Patrizio Parisini, Tiziana Greggi, Mario Di Silvestre, Federico Giardina, Georgios Bakaloudis Spine Surgery Dept., Rizzoli Orthopedic Institute, Via Pupilli, 1, 40136 Bologna, Italy

Abstract The high incidence and rapid progression of scoliosis in myelomeningocele make it one of the most disabling aspects of such disease. The choice of the surgical procedure to treat scoliosis in myelomeningocele is related to the peculiar features of this deformity. The purpose of this study is to review the results obtained by means of various surgical techniques and verify if posterior fusion with pedicle screws can improve results as compared to the single posterior approach. Patients were classified into three groups defined by treatment approach. The single posterior approach following either the Harrington or the Harrington-Luque technique yielded the least satisfactory results. The two-stage anterior-posterior spinal fusion provided good correction and stability. Correction and instrumented fusion through a single posterior approach with segmental fixation by means of pedicle screws proved to be valid and reliable, even when severe deformities had to be corrected and fused. In these latter cases pelvic fixation using ilio-sacral plates also made it possible to correct and stabilize pelvic obliquity.

1. Introduction Scoliosis is one of the most frequently (50-80%) encountered problems in myelomeningocele patients [1,2]. Since it progresses rapidly, very severe curves may develop early (Figure 1). Pelvic obliquity and deviations from the physiologic curves in the sagittal plane are the peculiar features. Trunk can really collapse on account of the thoraco-lumbar hyperkyphosis, or very severe lumbar hyperlordosis and pelvic obliquity can lead to lateral trunk shift. When the spinal deformity worsens, patients who cannot deambulate any more (or never could) may develop an imbalanced sitting position. Treatment with braces cannot generally decrease the high rate of progression of these deformities. Surgery therefore becomes mandatory to achieve, and above all maintain, adequate spinal balance and allow patients to tolerate pelvic obliquity. In most of the cases the aim of correction and fusion is to achieve at least a wellbalanced sitting position and preserve respiratory function [3]. Surgery for scoliosis in myelomeningocele is very demanding and often associated with complications [2,4]. The purpose of this study is to review and compare results obtained by means of various techniques. Above all, the present authors aim to verify if pedicle screws can improve the single posterior approach in terms of outcomes.

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Figure la. SA, A 1 yr-old boy affected with rapid evolving scoliosis secondary to myelomeningocele; Ib. at the age of 6 yrs ; Ic. at the age of 11 yrs ; Id. at the age of 14 yrs.

2. Materials and Methods A review of 33 patients surgically treated at our Department for scoliosis in myelomeningocele was undertaken. Subjects were divided into 3 groups of 10 fundamentally based on the different surgical approach used. Only three cases were excluded from the study since their follow-up was too short. Consequently, the study included 30 cases operated on from 1974 to 1997. There were 22 male and 8 female patients, aged 11.5 yrs on average (range, 2 to 22). The first group was made up of 7 male and 3 female patients, aged 12.6 yrs on average (range, 2 to 22). They were treated from 1974 to 1978 by single posterior approach using the Harrington technique in 3 cases and the same technique with sublaminar wiring fixation according to Luque in the remaining 7 cases. Distal fusion was extended to the sacrum in all cases. The second group was made up of 2 female and 8 male patients aged 11 yrs on average (range, 7 to 14 yrs). All the subjects received treatment during the 80s by combined anterior and posterior approach. The posterior approach was performed following the HarringtonLuque technique with fusion extended to SI in 4 cases, and following the Luque technique with Galveston fixation extended to SI in the remaining 6. Zielke and Dwyer instrumentation were used for the anterior procedure in 1 and 9 cases, respectively. Mean time interval between the anterior and posterior approach was 1 month. Treatment in one session was performed only in one case in which the double approach was carried out. The third group was made up of 3 female and 7 male patients always aged 11 yrs on average (range, 8 to 14 yrs). They were treated from 1995 to 1997 via a single posterior approach using segmental instrumentation with lumbar pedicular fixation, associated with laminar and pedicular hook fixation and sublaminar wiring in the thoracic region. Fusion was extended to L5 in the 2 cases who had good walking autonomy, whereas the remaining 8 cases with severe pelvic obliquity and complete paraplegia were fused to the sacrum and underwent pelvic fixation with ilio-sacral plates.

P. Parisini et ui / .Snn>icdl Treatment 1 Scoliosts in Mveloineningoceli'

Figure 2a. Harrington instrumentation; 2b. Harrington-Luque instrumentation posteriorly and Dwyer system anteriorly ; 2c. Posterior pedicular instrumentation with ilio-sacral plates.

3. Results Results obtained in the various groups were assessed and compared. At a mean followup of 15 years, a mean correction of scoliosis of 17%, no correction of hyperlordosis, and a modest correction of hyperkyphosis of 12% were observed in the historical group (patients treated only by posterior approach using the Harrington or Harrington-Luque technique) (Table 1).

FIRST GROUP SCOUOSIS KYPHOSIS PELVIC OBLIQUITY

Preop" 88 51 16

Postop0 65 31 7

Final Follow-up0 Improvement 17 73 57 12 50 8

Table 1 Ten complications were encountered (100%): 3 pseudarthroses, 4 dislodged instrumentation and 3 deep infections. Reinterventions were 7 (70%). Three cases with deep wound infection observed postoperatively, required wound revision and positioning of drainages. The remaining 4 reinterventions were necessary to repair a pseudarthrosis (2 cases), fix a dislodged hook (1 case) and adjust the instrumentation rods that protruded under the skin proximally. At an average follow-up of 11 years the following mean values were registered for the second group (patients treated by double surgical approach): correction of scoliosis of 57%,

P. Parisini et al. /Surgical Treatment of Scoliosis in Myelomeningocele

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correction of hyperkyphosis of 53%, correction of pelvic obliquity of 43%, and correction of hyperlordosis of 30% (Table 2). SECOND GROUP SCOLIOSIS KYPHOSIS PELVIC OBLIQUITY LORDOSIS

Preop0 101 93 37 95

Postop0 32 36 19 55

Follow-up0 43 44 21 67

Final lmprovement% 57 53 43 30

Table 2

The incidence of complications was equal to 70%: 2 pseudarthroses, 3 dislodged instrumentation and 2 deep infections. The total number of reinterventions in this group was 5 (50%). Three were carried out in the same patient: the onset of pseudarthrosis with loss of correction and recurrent severe pelvic obliquity made it necessary to perform a first revision of the posterior arthrodesis with removal of the Harrington-Luque instrumentation. Progressive traction was then exerted, and the Harrington-Luque system with compressor was subsequently applied surgically. Afterwards, two years after the first surgery, a deep infection with cutaneous fistula required a posterior surgical revision with partial removal of instrumentation and cutaneous plastic surgery. Another reintervention was carried out in a subject who showed severe worsening of the kyphosis above the fusion level that had been extended proximally. Finally, the remaining reintervention was performed in a case who had a distal subcutaneous protrusion secondary to dislodged posterior instrumentation with no loss of correction: the patient required posterior instrumentation removal. At an average follow-up of 3 years the following mean values were registered in the third group: correction of scoliosis of 47%, correction of hyperlordosis of 70%, correction of hyperkyphosis of 50%, and correction of pelvic obliquity of 40% (Table 3).

THIRD GROUP SCOLIOSIS KYPHOSIS PELVIC OBLIQUITY LORDOSIS

Preop0

85 71 25 117

Postop0 40 32 13 26

Final Follow-up0 lmprovement% 45 47 36 50 15 40 28 76

Table 3

Statistical analysis of the results (ANOVA) revealed a significant improvement (p2

Spine Deformity Correlates Better Than Trunk Deformity with Idiopathic Scoliosis Patients' Quality of Life Questionnaire Responses Marc Asher, Sue Min Lai, Doug Burton, Barbara Manna Kansas University Medical Center, Kansas City, Kansas USA Abstract. Aim : To determine whether either spine or trunk deformity measurements correlate with patients quality of life questionnaire responses. Materials and Methods: Forty five pre operative patients (5M, 40F), average age 15 years, 9 months (range, 10-20) met the inclusion criteria of age (£ 20 years), Posterior Trunk Symmetry Index (POTSI) and Suzuki Hump Sum (SHS) determination from surface topography, and Scoliosis Research Society -22 (SRS-22)patient questionnaire completion. Average measurement and measurement ranges were largest Cobb 62° (range, 40-137 °), POTSI 49 (range, 17-149), SHS 16 (5-32), and SRS-22 subtotal score 3.86 (range, 4.7-2.35). The individual SRS-22 domain scores were function 4.13 (4.80-2.20), pain 4.01 (51.60), self image 3.34 (4.4-1.80) and mental health 4.01 (5-1.80). (Scale 5 Best1 Worst). Correlations between deformity and questionnaire measurements were determined, p