Contents I MEDICAL RADIOLOGY. Diagnostic Imaging. Editors: A. L. Baert, Leuven M. Knauth, Göttingen K. Sartor, Heidelberg

Transcription

1

2 Contents I MEDICAL RADIOLOGY Diagnostic Imaging Editors: A. L. Baert, Leuven M. Knauth, Göttingen K. Sartor, Heidelberg

3 Contents III J. W. M. Van Goethem L. van den Hauwe P. M. Parizel (Eds.) Spinal Imaging Diagnostic Imaging of the Spine and Spinal Cord With Contributions by P. R. Algra C. Andreula D. Balériaux S. M. Belkoff R. G. Bhatia B. C. Bowen O. Boyunaga A. Cama S. Capoccia R. Cartolari A. Y. Choi M. Colajacomo C. Cristaudo P. Demaerel A. M. De Schepper M. Gallucci C. Gandolfo N. Gültaşli R. Gunzburg S. H. M. Kahn D. S. Katz P. E. Kim B. Koes J. Kråkenes S. J. Lypen M. Maes C. Manelfe L. Manfré M. Murrone A. O. Ortiz Ö. Özsarlak P. M. Parizel A. Rossi R. Salgado M. Szpalski E. T. Tali M. M. Thurnher P. Tortori-Donati G. Trasimeni A. Van Campenhout E. van de Kelft L. van den Hauwe J. W. M. Van Goethem F. M. Vanhoenacker M. van Tulder M. Voormolen C. S. Zee Foreword by A. L. Baert With 477 Figures in 1218 Separate Illustrations, 36 in Color and 67 Tables 123

4 IV Contents Johan W. M. Van Goethem, MD, PhD Department of Radiology, University Hospital Antwerpen Wilrijkstraat, Edegem, Belgium and Department of Radiology, Algemeen Ziekenhuis Nikolaas Moerlandstraat Sint-Niklaas, Belgium Luc van den Hauwe, MD Department of Radiology, University Hospital Antwerpen Wilrijkstraat Edegem, Belgium and Department of Radiology, AZ KLINA Augustijnslei Brasschaat, Belgium Paul M. Parizel, MD, PhD Department of Radiology, University Hospital Antwerpen Wilrijkstraat Edegem, Belgium Medical Radiology Diagnostic Imaging and Radiation Oncology Series Editors: A. L. Baert L. W. Brady H.-P. Heilmann M. Knauth M. Molls C. Nieder K. Sartor Continuation of Handbuch der medizinischen Radiologie Encyclopedia of Medical Radiology Library of Congress Control Number: ISBN Springer Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitations, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. Springer is part of Springer Science+Business Media http// Springer-Verlag Berlin Heidelberg 2007 Printed in Germany The use of general descriptive names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every case the user must check such information by consulting the relevant literature. Medical Editor: Dr. Ute Heilmann, Heidelberg Desk Editor: Ursula N. Davis, Heidelberg Production Editor: Kurt Teichmann, Mauer Cover-Design and Typesetting: Verlagsservice Teichmann, Mauer Printed on acid-free paper 21/3151xq

5 Contents V Foreword Medical imaging of the spine is among the most frequently performed diagnostic studies due to the high incidence of the very common clinical problem of acute or chronic back pain. Radiologists have a whole range of diagnostic modalities at their disposal to study spine pathology. It is of the utmost importance that they be familiar with the advantages and disadvantages of these different diagnostic techniques and are able to apply, in each clinical situation, the method that is most likely to optimally solve the clinical problem and indicate its correct management. Many authors, all well known specialists in their field, have contributed to this book which offers a very complete update of our current insights into and knowledge of common and less common disorders of the spine and the spinal cord. The illustrations are numerous, highly informative and of impeccable technical quality. I am very much indebted to the editors, J.W.M. Van Goethem, L. van den Hauwe and P.M. Parizel, for this superb volume which very much enriches the Medical Radiology series. It will be of great interest to radiologists in training, certified radiologists, as well as to neurosurgeons, neurologists and rheumatologists. Leuven Albert L. Baert

6 Contents VII Preface Diseases of the spine are very common. They affect up to 80% of the population worldwide and may cause pain, disability and economic loss. Pain or discomfort originating in the spine is usually a self-limiting condition. In more than 50% of patients, symptoms usually resolve spontaneously within 4 8 weeks, but there is a very high recurrence rate, estimated at about 85%. Back pain ranks seventh among the top costliest health conditions and is only preceded by heart disease, diabetes, hypertension, stroke-related conditions, osteoarthritis and pneumonia. Spinal imaging is one of the most common radiology procedures in general and is also the most performed MR imaging examination in many countries. Although the indication for spinal imaging in specific spinal problems, such as trauma, is evident, the role of imaging in the diagnosis of neck and low back pain often remains controversial. Many so-called radiographic abnormalities seen on CT and MRI are commonly also encountered in asymptomatic individuals, a phenomenon carefully explained in this book. This book aims to provide an overview of diagnostic spinal imaging. It is a comprehensive textbook with many illustrations and tables, yet easy to use with logical chapter-by-chapter coverage of different spinal pathologies. Extensive coverage of common spinal conditions, such as the degenerative diseases, spinal trauma, spinal surgery and imaging of the postoperative spine, spinal tumors, as well as spinal infection and inflammation, make this a very helpful book for everyday use in any practice involved with spinal imaging. I would like to take the opportunity to thank everybody who made this project possible. In the Name of Friendship My thanks go first of all to my co-editors, Paul Parizel and Luc van den Hauwe, without whom this book would not have existed. Luc was the originator, pointing out the fact that a volume on spinal imaging was missing in the Diagnostic Imaging series. Additionally, I have to thank Prof. Albert Baert for believing in our ability and giving us the opportunity to write this book. I also wish to thank the more than 40 contributors for their tremendous efforts in making this book possible; I know most of them personally and am very grateful to have been able to collaborate on this project with real friends. Finally, I have to thank Paul and Luc for their remarkable efforts in realizing this book together with me it would not have been possible without them.

7 VIII Preface In the Name of Love and Family This book could not have been completed without the continuing support of my wife, Isabelle, who, as a radiologist herself, not only understood my endeavours to complete this work, but who was also my most loyal supporter. As the mother of our three daughters, Alexia, Olivia and Félicia, she is also the cornerstone of our wonderful family and I wish to dedicate this book to these four women in my life. Edegem Johan W. M. Van Goethem This book is dedicated first and foremost to the ones I love: Marleen, my wife, and our children Vincent, Isabel, Liesa and Marie. Our children, they are the future. My thanks go to Paul and Johan, not only for teaching me neuroradiology, but primarily for their friendship. We have been working together for many years now in the spirit of the three musketeers (Les Trois Mousquetaires, a novel by Alexandre Dumas), inseparable men who chant the motto One for all, and all for one. Edegem Luc van den Hauwe I dedicate this book to: My wife, Vera, and to my son, Maxim, who mean everything to me My neuroradiology teachers in Antwerp, Boston, Brussels and Philadelphia, who programmed my brain with their wisdom and enthusiasm My friends and colleagues, Johan Van Goethem and Luc van den Hauwe, from whom I still learn everyday The happy coincidence which brought us all together: in infinito vacuo, ex fortuita atomorum collisione Edegem Paul M. Parizel

8 Contents IX Contents Congenital Congenital Malformations of the Spine, Spinal Cord, and Cranio-Cervical Junction Andrea Rossi, Carlo Gandolfo, Armando Cama, and Paolo Tortori-Donati 3 Pediatric Spine The Spine and Spinal Cord in Children Turgut Tali and Oznur Boyunaga Biomechanics Biomechanics of the Spine Stephen M. Belkoff Scoliosis Johan W. M.Van Goethem and Anja Van Campenhout Degenerative Disease Evidence-Based Medicine for Low Back Pain Maurits van Tulder and Bart Koes Degenerative Disc Disease Paul M. Parizel, Johan W. M. Van Goethem, Luc van den Hauwe, and Mauritis Voormolen Pathology of the Posterior Elements Luc van den Hauwe Spinal Stenosis Massimo Gallucci, Siliva Capoccia, and Mauro Colajacomo Spinal Instability Axial Loaded Imaging of the Spine Luigi Manfré, Roberto Cartolari, Guido Trasimeni, and Concetto Cristaudo Osteoporosis Insufficiency Fractures Menno Maes

9 X Contents Trauma Whiplash Injuries Jostein Kråkenes Cervical Trauma Özkan Özsarlak Thoracolumbar Spine Trauma Rita G. Bhatia and Brian C. Bowen The Postoperative Spine Surgical Procedures: Discectomy and Herniectomy Erik Van de Kelft Imaging of the Postoperative Spine: Discectomy and Herniectomy Johan W. M. Van Goethem and Rodrigo Salgado Surgical Procedures: Cages, Prostheses, and Instrumentation Robert Gunzburg and Marek Szpalski Imaging of the Postoperative Spine: Cages, Prostheses and Instrumentation Paul E. Kim and Chi Shing Zee Tumors Intradural Spinal Tumors Danielle Balériaux and Neslìhan Gültaşli Metastatic Disease of the Spine Cosma Andreula, Mario Murrone, and Paul R. Algra Primary Tumors of the Osseous Spine S. H. M. Kahn and Arthur M. De Schepper Bone Marrow Spinal Bone Marrow Disorders Philippe Demaerel Infection and Inflammation Spinal Infections Majda M. Thurnher Seronegative Spondylarthropathy Claude Manelfe and Filip M. Vanhoenacker Sacrum Imaging of the Sacrum Andrew Y. Choi, A. Orlando Ortiz, Douglas S. Katz, and Steven J. Lypen Subject Index List of Contributors

10 Congenital Malformations of the Spine, Spinal Cord, and Cranio-Cervical Junction 1 Congenital

11 Congenital Malformations of the Spine, Spinal Cord, and Cranio-Cervical Junction 3 Congenital Malformations of the Spine, 1 Spinal Cord, and Cranio-Cervical Junction Andrea Rossi, Carlo Gandolfo, Armando Cama, and Paolo Tortori-Donati CONTENTS 1.1 Congenital Malformations of the Spine and Spinal Cord Introduction Embryology Gastrulation Primary Neurulation Secondary Neurulation Development of the Vertebral Column Terminology Open and Closed Spinal Dysraphisms Spina Bifida Placode Tethered Cord Building a Classification Classifying Open Spinal Dysraphisms Classifying Closed Spinal Dysraphisms Open Spinal Dysraphisms Myelomeningocele and Myelocele Hemimyelomeningocele and Hemimyelocele Closed Spinal Dysraphisms CSDs with Subcutaneous Mass CSDs without Subcutaneous Mass Congenital Abnormalities of the Cranio-Cervical Junction Bony Abnormalities Basilar Invagination Achondroplasia Down Syndrome Klippel-Feil Syndrome Chiari Malformations Chiari-I Malformation Chiari-II Malformation Chiari-III Malformation Chiari-IV Malformation 37 References Congenital Malformations of the Spine and Spinal Cord Introduction Congenital malformations of the spine and spinal cord are generally referred to as spinal dysraphisms. These conditions are usually diagnosed prenatally, at birth, or in early infancy; however, some may be discovered in older children or adults. Magnetic resonance imaging (MRI) has made the diagnosis of these disorders easier, faster, and more accurate, thereby enhancing the possibility of an early and case-tailored treatment, mainly thanks to its multiplanar imaging and tissue characterization capabilities. Classification of spinal dysraphisms requires a balanced correlation of clinical, neuroradiological, and embryological information. Use of classification schemes may prove helpful in making a diagnosis in everyday clinical practice (Tortori-Donati et al. 2000; Tortori- Donati et al. 2001; Rossi et al. 2004a,b; Tortori- Donati et al. 2005b). Although the MRI picture in patients with spinal cord malformations may appear complicated and puzzling even to the experienced observer, we believe that a rational approach focusing on a correlation among clinical, embryological, and neuroradiological data greatly facilitates the diagnosis. Neuroradiologists should pursue the maximum degree of collaboration with neurosurgeons and other specialists involved in the management of A. Rossi, MD Senior Staff Neuroradiologist, Department of Pediatric Neuroradiology, G. Gaslini Children s Research Hospital, Largo G. Gaslini 5, Genoa, Italy C. Gandolfo, MD Staff Neuroradiologist, Department of Pediatric Neuroradiology, G. Gaslini Children s Research Hospital, Largo G. Gaslini 5, Genoa, Italy A. Cama, MD Head, Department of Pediatric Neurosurgery, G. Gaslini Children s Research Hospital, Largo G. Gaslini 5, Genoa, Italy P. Tortori-Donati, MD Head, Department of Pediatric Neuroradiology, G. Gaslini Children s Research Hospital, Largo G. Gaslini 5, Genoa, Italy

12 4 A. Rossi, C. Gandolfo, A. Cama, and P. Tortori-Donati KEY POINTS Spinal Dysraphism General term used for congenital malformations of the spine and/or spinal cord. Spina bifida is widely used as a synonym but strictly speaking only indicates defective fusion Caused by embryological derangement between gestational weeks 2 and 6 Open spinal dysraphism (OSD; characterized by exposure of nervous tissue through a congenital defect Almost 99% are myelomeningoceles Variable degree of sensorimotor deficits, bowel and bladder dysfunction All patients with OSD have Chiari II Role of MRI: anatomic characterization; presurgical evaluation; identification of cord splitting when present Closed spinal dysraphism (CSD) is covered by skin and has two main subtypes: CSD with subcutaneous mass In the vast majority this mass is a lipoma tethering the spinal cord: lipomyelo(meningo-)cele CSD without subcutaneous mass are often clinically occult and several types are recognized among which: Intradural lipoma Filar lipoma Tight filum terminale: conus inferior to L2 Dermal sinus: above the intergluteal cleft Persistent terminal ventricle, usually asymptomatic except when very large Diastematomyelia: split cord. Associated tight filum terminale, hydromyelia, vertebral anomalies, and/or scoliosis are common. Type I with osteocartilaginous spur, type II without spur Caudal agenesis: total or partial agenesis of the caudal portion of the spine, anal imperforation, genital anomalies, renal dysplasia, pulmonary hypoplasia, and/or lower limb anomalies. Type I with high and abrupt-ending conus, type II with low and tethered conus. Congenital malformations of the cranio-cervical junction Can be bony and/or nervous Measurements: Chamberlain s line: hard palate posterior margin foramen magnum McGregor s line: hard palate lowest point occipital bone Chiari-I malformation Cerebellar tonsils >5 mm below basion-opisthion line or 3 5 mm and neurological signs or peg-like tonsils or syrinx 14 56% neurologically normal Significant incidence of hydrosyringomyelia and/or hydrocephalus Chiari-II malformation Small posterior fossa Downward displacement of vermis, brainstem and fourth ventricle 90% has OSD Associated brain malformations Chiari-III malformation Chiari II + cephalocele Chiari-IV malformation Severe cerebellar hypoplasia + myelomeningocele

13 Congenital Malformations of the Spine, Spinal Cord, and Cranio-Cervical Junction 5 these patients in order to improve their diagnostic capabilities and to provide more useful information for the management of these children. In this chapter, the basic concepts about normal and deranged spinal cord embryogenesis are summarized, the principal malformations are described, and a practical approach to neuroradiological decision-making is offered. Additionally, because the Chiari-II malformation is part of the myelomeningocele malformative spectrum, the Chiari malformations are also discussed in this chapter Embryology Spinal dysraphisms are caused by derangements that occur during a fairly limited period of time in the early embryological development, situated between gestational weeks 2 and 6. During this period, three consecutive stages occur, i.e., gastrulation (weeks 2 3), primary neurulation (weeks 3 4), and secondary neurulation (weeks 5 6) (Tortori-Donati et al. 2000; Tortori-Donati et al. 2001; Rossi et al. 2004a,b; Tortori-Donati et al. 2005b) Gastrulation During gastrulation, the bilaminar embryonic disk, formed by epiblast (future ectoderm) and primitive endoderm is converted into a trilaminar disk because of formation of an intervening third layer, the mesoderm (Fig. 1.1). This process begins by day 14 or 15 when the primitive streak, a stripe of thickened epiblast composed by totipotential cells, appears along the midline of the inferior portion of the dorsal surface of the embryo. The primitive streak has a knob-like cranial termination called Hensen s node. Epiblastic cells start migrating toward the primitive streak and pass inward at the primitive pit, a central depression of Hensen s node, to ingress the interface between the epiblast and the primitive endoderm. Subsequent waves of epiblastic cells migrating laterally along the interface form the interposed mesoderm, whereas cells migrating along the midline form the notochord. The notochord is the foundation of the axial skeleton and extends throughout the entire length of the future vertebral column. From the mesoderm surrounding the neural tube and notochord, the skull, vertebral column, and the membranes of the brain and spinal cord are developed. The notochord is traditionally believed to induce the overlying ectoderm that differentiates into neural ectoderm; however, it has been hypothesized that the default state of the ectoderm is neural ectoderm, and that the notochord is required to preserve such condition (Naidich et al. 2002) Primary Neurulation Establishment of the neural plate marks the onset of primary neurulation (Fig. 1.2). This occurs on about day 18, when the neural plate starts bending, forming paired neural folds. In the following days, these progressively increase in size and approach each other to eventually fuse in the midline to form the anterior Prochordal plate dorsal Primitive streak Epiblast Notochordal process Hensen s node ventral Primitive ectoderm Prospective mesoderm b a posterior Primitive streak Cloacal membrane Fig. 1.1a,b. Gastrulation. a Dorsal view and b transverse view of the bilaminar embryonic disk. First ingressing cells at Hensen s node move anterior to form head processes and notochord. Cells ingressing through primitive streak migrate ventrally and laterally to form mesodermal and endodermal precursors

14 6 A. Rossi, C. Gandolfo, A. Cama, and P. Tortori-Donati neural tube. According to the traditional zipper model, closure of the neural tube occurs first at level of the fourth somite (future craniocervical junction) and then proceeds both cephalad and caudad. The cranial extremity of the neural tube (rostral or anterior neuropore) closes at day 25, whereas the caudal extremity (caudal or posterior neuropore) closes at days 27 or 28. Closure of the posterior neuropore marks the termination of primary neurulation Secondary Neurulation The posterior neuropore, corresponding to the caudal extremity of the primary neural tube, corresponds to the 32nd somite, i.e., the future third sacral metamere. The segment of the spine and spinal cord caudad to somite 32 is formed by secondary neurulation (Fig. 1.3). This embryological step begins immediately after completion of primary neurulation and proceeds until approximately gestational day 48. During secondary neurulation, the tail bud, a mass of cells deriving from the caudal portion of the primitive streak, lays down an additional part of the neural tube caudad to the posterior neuropore. This cord segment differs from the one formed by primary neurulation in several ways. While the primary neural tube results from an upfolding of the lateral borders of the neural plate which join at the midline, the secondary neural tube is formed by an infolding of the neural plate, creating an initially solid medullary cord that subsequently becomes cavitated (Catala 2002; Nievelstein et al. 1993). The fate of the secondary neural tube is to undergo an incompletely understood process of regression, degeneration, and further differentiation, called retrogressive differentiation. This process results in the formation of the tip of the conus medullaris, which contains the lower sacral and coccygeal cord metameres, and the filum terminale, a fibroconnectival structure practically devoid of neural elements. Notably, retrogressive differentiation has not been clearly demonstrated Anterior neuropore Neural plate Neural crest Neural plate Neural groove Notochord Neural folds Neural groove Fused neural folds Somite Neural groove Surface ectoderm Neural crest Neural groove Posterior neuropore Neural crest a Neural tube Skin Fig. 1.2a,b. Primary neurulation. a Dorsal view of the embryo on gestational day 21 shows fusion of the neural folds to form a neural tube has begun at the cervical level and proceeds bidirectionally. b Set of transverse views shows evolution from flat neural plate to fused neural tube. Also notice disjunction of the neural ectoderm from the surface ectoderm at the time of neural tube fusion Neural tube Spinal ganglia b

15 Congenital Malformations of the Spine, Spinal Cord, and Cranio-Cervical Junction 7 Notochord Terminal ventricle a Tail bud Primary neural tube b Secondary neural tube Fig. 1.3a-c. Secondary neurulation. a The tail bud forms as a result of coalescence of the neuroectoderm with the lower notochord. b A secondary neural tube connects cranially with the neural tube formed by primary neurulation. c Eventually, the tip of the conus medullaris and the filum terminale result from this process. The terminal ventricle is the sole remnant of the secondary neural canal (From Tortori-Donati et al. 2005a) c Filum terminale in humans, and a lack of proliferation, rather than regression or degeneration, could actually account for the rudimentary character of the filum terminale (M. Catala, pers. commun.). The conus medullaris contains a focal expansion of the ependymal canal called terminal ventricle, representing the remnant of the lumen of the secondary neural tube Development of the Vertebral Column At first, the paraxial trunk mesoderm is unsegmented. As development proceeds, epithelial spheres, called somites, are formed in a cephalo-caudal gradient. These somites mature during development according to a cephalo-caudal gradient. This maturation leads to dissociation of the epithelial somite, forming the dermatome (dorsal), the myotome (intermediate), and the sclerotome (ventral). The dermatome is located underneath the surface ectoderm. It will give rise to dermal cells for the dorsal moiety of the body. The myotome gives rise to all striated muscle fibers of the body. The sclerotome differentiates into cartilaginous cells of the vertebrae, cells of the intervertebral discs and ligaments, and cells of the spinal meninges. Furthermore, the somite gives rise to endothelial cells. The sclerotome is first located ventrally, and then it spreads to enwrap the entire neural tube forming at its dorsal face, the so-called dorsal mesoderm that will insinuate itself between the neural tube and the surface ectoderm after disjunction. On a next step of differentiation, the sclerotomes divide in half horizontally; the bottom half of one fuses with the top half of another to form the vertebrae. Notochordal remnants between the vertebrae become the nucleus pulposus within the intervertebral disk Terminology Open and Closed Spinal Dysraphisms Etymologically dysraphism implies defective closure of the neural tube and should therefore be used to refer to abnormalities of primary neurulation only; however, the term has gained widespread use as a synonym to congenital spinal cord malformation. Spinal dysraphisms are categorized into open spinal dysraphisms (OSD) and closed spinal dysraphisms (CSD) (Tortori-Donati et al. 2000; Tortori-Donati et al. 2001; Rossi et al. 2004a,b; Tortori-Donati et al. 2005b). The OSDs are characterized by exposure of nervous tissue to the environment through a congenital defect in the child s back. On the contrary, CSDs are covered by skin, although cutaneous birthmarks, such as angiomas, dimples, overgrowing hair, dyschromia, and dystrophy, are present in more than 50% of cases (Drolet 1998; Warder 2001). Use of the term occult spinal dysraphisms is discouraged as it suggests complete absence of external abnormalities, a condition that occurs only in a minority of CSDs (Tortori-Donati et al. 2000) Spina Bifida Strictly speaking, spina bifida indicates defective fusion of the vertebral neural arch (French 1983); however, it is widely used as a synonym of spinal dysraphism. The terminology spina bifida aperta (or cystica ) and spina bifida occulta refers to OSD and CSD, respectively (Sattar et al. 1996),