Springer Berlin Heidelberg New York Barcelona Budapest Hong Kong London Milan Paris Santa Clara Singapore Tokyo Spinal Meningiomas A. PANSINI F. P. Lo RE - CONTI - R. CONTI E. G. MONTALI - DE LUCA Springer ARNALDa PANSINI MD, Professor of Neurosurgery Director of the Department of Neurological and Psychiatric Sciences Director of the Department of Neurosurgery University School of Medicine of Florence-Italy FULVIO La RE MD, Professor of Neurosurgery PIERO CONTI MD, Professor of Neurosurgery RENATa CONTI MD, Professor of Neurosurgery Department of Neurological and Psychiatric Sciences Department of Neurosurgery University School of Medicine of Florence-Italy ENRICO MONTALI MD, Professor of Genetics Department of Clinical Pathophysiology University School of Medicine of Florence-Italy GIOVANNI DE LUCA MD, Professor of Neurophysiology Department of Neurological and Psychiatric Sciences Department of Neurosurgery University School of Medicine of Florence -Italy ISBN 978-88-470-2262-1 ISBN 978-88-470-2260-7 (eBook) DOl 10.10071978-88-470-2260-7 Die Deutsche Bibliothek - CIP-Einheitsaufnahme Spinal Meningiomas: A. Pansini ... -Berlin; Heidelberg; New York: Springer, 1996 ISBN 978-88-470-2262-1 NE: Pansini, Arnaldo This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of trans lation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in data banks. Dupli cation of this publication or parts thereof is only permitted under the provisions of the German Copyright Law of September 9, 1965 in its current version, and a copyright fee must always be paid. © Springer-Verlag Italia, Milano 1996 Softcover reprint of the hardcover 1st edition 1996 The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: the publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. Cover design by Marco Vaghi Spinal Meningiomas Preface This volume follows an earlier collection of cases from and the internal structures of the rachis. the Institute of Radiology at the University of Florence There are l25 cases of meningiomas in this mono entitled "Early Diagnosis ofM yeloradicular Compressions, graph, derived from the surgical treatment of 125 cases X-Ray, CT, MRI," (A. Pansini, P. Conti and Collaborators, of meningiomas operated on between 1962 and 1994. In 1987) which dealt with the diagnosis not only of spinal recent years surgical techniques have undergone a grad tumours but also of compressions of other natures. There ual evolution, making the removal of any form of menin we expressed the view that the new diagnostic techniques gioma safer than it was in the past. available today for the early diagnosis of medullary com Our intention in presenting these experiences in the pressions should by no means exclude other diagnostic diagnosis of meningiomas is to expand our knowledge procedures. After presenting in the previous volume the of the techniques available and of the respective roles most common radiographic and myelographic aspects which they can play in reaching an early diagnosis, there for the diagnosis of spinal tumours, we now evaluate the by improving surgical results. diagnostic capabilities of computed tomography (CT), My own deepest gratitude goes to my junior neuro myelo-CT and magnetic resonance imaging (MRI) which surgeons and to my Associate Professors F. Lo Re, P. Conti reveal the importance of these most recent methods of and R. Conti who have collaborated in clinical diagnoses, investigation. In our first publication, the comparative and complete surgical activity, and to the assistance of study of various methods was not restricted to the diag patients at the Neurosurgical Clinic of the University of nosis of spinal tumours but extended also to compres Florence which I have had the honour of directing since sions of other natures. 1970. This monograph has been completed with their val The experience we acquired in evaluating the various uable assistance, during the course of the years, by keep diagnostic investigations in medullary compression cases, ing rigorous accounts of all clinical observations over this prompted us to use a similar approach in examining a period, evaluated from an evolutionary perspective and series of meningiomas. In contrast to tumours which show with the addition of comments added immediately after an early onset of symptoms, meningiomas, among the each operation. primary intrarachidian tumours, are particularly subject We wish to thank our colleagues in the Department to a delayed development of symptoms. of Genetic Medicine at the University of Florence, who x We cannot stress enough the importance of a plain worked in close collaboration with the Neurosurgical ray of the rachis in the diagnosis of meningiomas. This is Clinic and participated in this study from a cytogenetic considered as being the fundamental neurological pro point of view, paying special attention to chromosomic cedure to be performed before all others, as it provides the anomalies of some tumours with particular emphasis on basis for identification of characteristic details which spinal meningiomas. Our gratitude is extended to Prof. E. assist in reaching an early diagnosis of medullary compres Montali and to Dr. L. Papi who have recorded data of their sions from tumours. experiences in the chapter on genetics. We also wish to In addition to the images supplied by CT and MRI, thank our neurophysiopathology assistant, Prof. G. De we have stressed the importance of myelo-CT features Luca, who handled the recordings of pre-, intra -and post and the axial scans produced with an iodine contrast operational evoked potentials, and who contributed to medium introduced by means of lumbar puncture, which the chapter on neurophysiopathology. very clearly identify the borders of pathological tissue Dr. A. Franchi from the Institute of Anatomy and v Preface Pathological Histology at the University of Florence dealt F. Cioffi, Dr. J. Buric, Dr. S. Carnesecchi, and Dr. S. Romoli. with and closely examined all the histopathological mate Thanks also to the technicians of the Radiological rial on the 125 menigiomas, classifying them according Service: Maurizio Galli and Riccardo Lombardo. to the WHO criteria. Our sincere thanks we express to We are also indebted to Professor G. Staderini, Direc him, particularly for the meticulous work which he carried tor of the Didactic Television Centre at the University of out in the preparation of the staining methods. Florence, and to his collaborators G. Guidi and his techni Our gratitude also goes to all of our radiologist and cians who produced the long-distance images taken dur neuroradiologist colleagues and particularily to Prof. G. ing surgery, allowing us to demonstrate the highlights of Dal Pozzo, G. Pellicano and to Dr. S. Mangiafico who car the surgical techniques employed. These were recorded ried out the necessary neuroradiological investigations on video tape and were recently presented at the Euro on the clinical material which we supplied and helped pean Congress of Neurosurgery in Berlin. us to identify the exact location and nature of the lesions. Our gratitude and sincere thanks we also extend to Sincere thanks to the young assistants and to those the distinguished publisher Springer-Verlag for their inter specializing in neurosurgery, who have worked with ded est shown and for the collaboration in the preparation ication and competence on the study of clinical material, and editing of this monograph. on the elaboration of all statistical data and on postoper ative checks. These include Dr. P. Bono, Dr. P. Gallina, Dr. A. Pansini VI Spinal Meningiomas Contents 1 General Considerations .................................................................................................................. 1 2 Historical Origins of Embryology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 Genetics .............................................................................................................................. . . . . . . . . 7 4 Vascularization of the Spinal Cord and Variations in Myelitic Blood Flow ................................................. 9 5 Case Reports....................................................................................................................... ......... 15 6 Clinical Symptoms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 6.1 Regionally Localized Pain. .. ... .. ... .. .. .. .. . ... .. .. . .. .. .. ... .. .. .. .. .. .. .. .. .. .. . .. .. . .. .. .. . .. .. ... ... . ... . . .. ... .. .. . .. .. .. .. .. 23 6.2 Sensory Radicular Symptoms. .. .. ... .... .. .. .. .. .. .. ... .. .. . . . .. .. .. .. .... .. .. .. .. . .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 28 6.3 Cervical Root Syndrome ........................................................................................................... 31 6.4 Dorsal Root Syndrome. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 6.5 Lumbar Root Syndrome... .. ... .. ... .. .. .. . .. .. ... .. ... .. .. . .. .. .. .. .. .. .. .. .. .. .. . . . .. ... .. .. . . . . .. .. .. .. .. ... . .. .. .. .. .. .. .. . .. .. 37 6.6 Sensory Cord Syndrome ........................................................................................................... 37 6.7 Motor Cord Syndrome ............................................................... " .. ... .. .. . .. .. .. .. .. .. .. ... .. . . .. .. .. . . . .. .. . 37 6.8 Brown-Sequard Syndrome..... .............. ..... ................................ ................................................. 38 6.9 Clinical Signs in the Development of Meningiomas. .. .. . .. ... ...... . .. .. .. .. . .. .. . .. .. .. . .. .. .. .. .. .. .. .. . .. .. .. .. .. . .. .. .. 39 6.9.1 Cervical Tract.................................................................................................................. 39 6.9.2 Dorsal Tract .................................................................................................................... 40 6.9.3 Lumbar Tract.. .. .. .. . .. ... ..... ... .. .. .. .... .. .. .. .. .. ..... .. .. .. .. ... .. . .. .. .. .. . .. ... .. .. .. . .. .. .. .. ... .. ..... . .. .. .. .. .. .. .. 44 6.10 Differential Diagnosis ....................................................................................... " .. .. ... .... .. .. .. .. .. . 44 6.11 Causes of Diagnostic Error and Delay.. .. .. ..... .. .. .. . .. .. .. .. .. .. .. .. ... ... .. .. ... .. . .. .. . ... . . . .. .. .. ... .. .. .. .. .. .. .. .. .. .. 46 6.12 Supra-and Sublesional Symptoms ........................................ " .. .. . .. .. ... .. . .. .. .. .. .. .. .. .. .. .. .. ... . .. .. .. .. .. .. 50 6.13 Von Recklinghausen's Disease .................................................................................................... 51 6.14 Rare Cases ............................................................................................................................. 56 6.15 Conclusions.................................................................................................................... ........ 66 VII Contents 7 Neurophysiopathology.......................................................................................................... . . . . . . . . . 69 7.1 Evoked Potentials .................................................................................................................... 69 7.2 Somatosensory and Motor Evoked Potentials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 7.3 Intraoperative Neurophysiological Monitoring .............................................................................. 70 7.4 Materials, Methods, Case Reports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 7.5 Results, Discussion, Conclusions................................................................................................. 80 8 Neuroradiology................................................................................................................. . . . . . . . . . . . . 83 8.1 Bone Alterations from Compression of the Meningioma on the Vertebral Sac.. .. .. ... .. ... .. ... . .. ... . ... ... .... . .. 83 8.1.1 Modification of a Single Pedicle ........................................................................................... 86 8.1.2 Bilateral Peduncular Alterations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 8.1.3 Morphological Alterations in the Vertebral Body .................................................................. , . . 91 8.2 Calcifying Features of a Meningioma.. . .. .. . .. .. ... .. .. .. .. . .. .. .. . .. .. . .. . .... .. .. .. .. ... .. .. .. .. . .. .. . .. .. . .. ... ... . .. . .. . ... 100 8.3 Neuroradiological Diagnostic Examinations.. . .. .. .. .. . .. .. .. . .. .. ... .. ... .. .. .. ..... .... .. .... . .. ..... .. . .. .. ... .. . .. ... ... . 111 8.3.1 Myelography ................................................................................................................... 111 8.3.2 Computed Tomography..................................................................................................... 117 8.3.3 Myelo-Computed Tomography............................................................................................ 119 8.3-4 Magnetic Resonance Imaging.... .. . .. .. . .. .. .. ....... .. .. ... .. ... .. . .. .. .. . .. .. .. .. .. .. .. ... .. .. ... .. .. . .. .. . .. .. . .. ... .. . 129 8.3.5 Angiography ................................................................................................................... 143 8.4 Conclusions.................................................................................................................... .. .. . .. . 143 9 Surgical Techniques................ .................................. ....... ..... ..... .................................. ............ ...... 147 9.1 Microscopic Features and Variations in the Relationship with the Spinal Dura and Leptomeningeal and Myeloradicular Structures ................................................................................................... 147 9.2 Neighbouring Relationships with the Leptomeninges.. ... .. .. . .. .. . .. .. . .. .. .. .. .. .. .. . .. .. .. . .. .. .. . .. .. ... .. .. . .. .. . .. .. 147 9.3 Position of the Patient .............................................................................................................. 148 9.4 Laminectomy, Lamina-arthrectomy with Foraminotomy.................................................................. 149 9.5 Deformations of the Spinal Dura as Seen in the Operative Microscope................................................ 150 9.6 Microsurgical Splitting of the Dura and Variations in Dural Incisions................................................. 156 9.7 Opening the Arachnoid. . .. .. .. ..... .. ...... .. .. ... .. ... ... .. .. . .. ... .. ... .. .. .. ... .. ..... .. .. .. ... .. .. . .. .. . .. ... .. . .. . .. ... .. ... .. 168 9.8 Radicotomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 9.9 Modes of Excision ......... , .. . .. .. .. .. .. .. .. .... ... .. ... .. . .. .. ... .. ... ... .. .. .. ... .. .. .. .. . .. .. .. . .. .. .. . .. .. . .. ... .. . .. .. . .. ... .. . . 171 9.10 Complications and Follow-Up............... ..... ..... .......... ... ....... ............. .............. ........... ..... ........ .... 189 9.11 Conclusions.................................................................................................................... .. ..... . 190 10 Other Anatomical-Clinical Observations ................................................... , .. ... .. .. ... .. ... ... ... ... .. . .. ... ... .. . 193 References ............................................................................................................................... . . . . . . . . 223 VIII Spinal Meningiomas General Considerations 1 The traditional division of primary intradural-extramed ularly elongated, being both intra-and extrarachidian at ullary spinal tumours, intramedullary and epidural the same time. It is important to note at the beginning tumours is still used today to describe tumours on the that its structure together with its histological variants basis of location. However, one must also consider that a is identical to cerebral meningioma, and the spinal menin meningioma can grow towards the inner spinal dura and gioma is sometimes clinically confused with a neurinoma in the epidural site, thereby becoming extrameningeal at or neurofibroma, not only in structure but also because the same time. The various forms of development are both undergo a slowly progressive course of development associated with the histological nature of the tumour; and show similar initial symptoms. When the lesion syn benign characteristics and transformation processes drome is minimal and motor impairment is slight, man towards malignancy, which brings about an alteration in ifest by the swaying motion of the lower limbs, one is the dimension of the tumour although the tumour attach reminded of the numerous types of cord syndromes. ment remains well defined. However, the presence of constant pain leads to perplex Meningeal tumours are referred to as meningioma, ity in diagnosing noncompressive root syndromes; radic the term proposed originally by Cushing. This refers to a ular coinvolvement at the lumbar level, often on one side particular type of tumour characterized by the same ele only, or with some contraradicular sensitivity, suggests ments that constitute the connective tissues of the menin a possible painful cauda syndrome which is not of tumour ges, to such a degree that it becomes easy to distinguish the ous nature. In cases in which the meningioma is com major fibre component in the histological classification. pletely extradural and extends out of the vertebral canal These are distinguished from tumours that undergo trans through the intervertebral foramen, the initial pattern of formation of a degenerative or other nature which may sensitive disturbance is the same as that of the neurofi develop into neoplasm and, especially, those that show bromas with hourglass appearance. This sensitive distur distinct signs of dysembryogenetic development. bance is also frequently found at the level of the dorsal The spinal meningioma inserts itself on the spinal spine. dura and is a well-defined tumour, varying in consisten In the forms with the level syndrome restricted to cy in each case, subject to a variable progressive course but the grey matter of the cervical spine in the initial phase of frequently a very slow formation. The morphological meningiomatous compression one must consider mye appearance of meningiomas is described as encapsulated lopathy, especially in the presence of arthrosis alterations by a dense connective tissue formation under which the on the cervical tract of the spine, which may also account intrinsic tissue of the tumour may appear friable, haem for the symptoms of second motor neuron involvement. orrhagic, soft or otherwise dense, fibrous, strident in the These simple caveats, which are not the only ones, have excision phase, not very haemorrhagic, of a yellowish been evaluated in recent publications on the progressive white colour and granular due to its calcifying transfor course of meningiomas. We draw attention to the vari mation. Other forms have a hard, compact consistency ous possible diagnoses to underline the fact that a menin similar to bone tissue. Normally when a diagnosis is gioma is a tumour which delays in showing recognizable reached the tumour shows an exclusively intradural devel signs of a compression, misguiding the clinical discus opment and has the size of a cherry. sion to other pathologies. There are other forms, however, which are much Diagnosing intrarachidial compression simply with larger, especially when the meningioma becomes partic- the help of the patient's medical history and clinical signs 1 1 General Considerations already present, frequently proves too late in the case of a literature that has accumulated over the past 10 years is suspect tumour to request neuroradiological confirmation. reviewed but without neglecting previous fundamental In many forms of tumours this delay could influence sur work on this subject, including particularly diagnostic gical results, particularly when the preoperative semio aspects and therapy. logical picture expresses bilateral involvement of the cord, The impressive set of statistical data collected by affecting movement in a way resembling severe parapar Pagni from the most important neurosurgical centres of esis tending towards paraplegia. the world has been an enormous help to us. We have At the October 1988 Turin Congress on "Primary included references from this work and used a similar Tumours of the Spinal Cord" we were indebted to Pagni for methodology in order to produce a significant contribu presenting the most valuable and up-to-date information tion from a neurodiagnostical point of view, with the addi ever collected on this pathology. This Congress also dis tion of some innovative details regarding the techniques cussed experimental research and genetics as these areas that we use. may in future prove crucial in the search for means to We also include here our considerations after each modify and improve acute or chronic damage to the cen operation as these observations, together with the explan tral nervous system. atory and schematic diagrams of the relationship between This monograph examines a series of 122 meningio tumours and the myeloradicular structures, may contrib ma cases operated on by the same group of neurosur ute to much more accurate interpretation of the anatom geons from the University of Florence between 1962 and ical-clinical picture. This was made possible by the oper 1994. The data include those from the period (1962-1980) ative microscope and by micro neurosurgery, which has when neuroradiological diagnosis depended solely upon improved our surgical techniques. myelography performed suboccipitally. The subsequent This monograph concludes with an evaluation of the introduction of computed tomography (CT) and mag various elements regarding spinal meningiomas and the netic resonance imaging (MRI) has allowed us to consid problem of early diagnosis, which continues to be of fun er many additional clinical-anatomic factors. The vast damental importance in obtaining optimal results. 2 Spinal Meningiomas Historical Origins of Embryology 2 A. Pansini - P. Conti Following the pioneering research by His (1890), Salvi been provided by Levi-Montalcini (1950,1967), Hambur (1897) and Kolliker (1896) on the differentiation of the ger (1952), Harris (1965) and Romanes (1951,1964). neural tube, many researchers studied particular aspects In young embryos the outline of the cord shows an of cellular development in neuroepithelium. According irregular oval shape; as seen in a cross-section, the later to His' theory, the neuroepithelium is heterogeneous in al sides are thick while the ventral and dorsal sides are nature, and the spongioblasts in their ventricular site thin, leading to their being termed lamina. The ventral gradually move away from one of the bordering mem side is called the basal lamina and the dorsal side the teg branes and assume the cellular nature of astroblasts, astro mental lamina. In a cross-section of a I-month -old embryo cytes, oligodendroblasts or oligodendrocytes. The spon the cavity of the cord resembles a fissural lumen, such as gioblasts which remain connected to the internal mem a great vertical axis. In embryos older than 1 month the lat brane form the future ependymal cells. eral sides of the cord present increased thickness and a sag Salvi (1897) used the term primitive meninges for ittal sulcus in the interior wall (bordering sulcus) that all the layers between the cord and the vertebral primor separates a higher and thicker ventral portion which is dium. However, this mesenchyma constitutes the menin shorter and thinner and is known as the wing lamina. On ges and the endorachis, and Sterzi (1915) referred instead each side on the surface of the fundamental lamina the to the perimedullary mesenchyma, which later divides anterior and lateral cords of the white matter differen into two layers: one adhering to the vertebrae and form tiate and the anterior grey horns, from within the lamina, ing the endorachis and the other surrounding the cord give rise to the anterior spinal root. Peripherally from the forming the early primordium of all the meninges. This is wing lamina, the posterior white cord differentiates from the only feature which could properly be termed primitive the deep grey horn, from which arises the posterior spi meninges. According to Sauer (1935,1936), the neuroepi nal root medially. thelium during the very early phases of development is In this phase the exterior of the spinal cord appears formed by a homogeneous grouping of cells whose pro in cross-sections as a triangle with a large base situated liferation and differentiation stabilize eventually at a spe ventrally and the rounded apex rising dorsally. The cav cific point to form the matrix or ventricular layer. This ity still appears in the shape of a vertical fissure as a great layer is formed by cells with a particular selective poten axis. The bordering sulcus enlarges the fissure as it joins tial of differentiation and is considered responsible for two-thirds of its length ventrally and one-third dorsally. the origin of all the elements that form the adult nervous The cavity of the cord which represents the future epen system. Sauer's theory has been confirmed by numerous dymal cavity then declines in height as the posterior por researchers, including Watterson et al. (1956), Sidman and tion, which corresponds to the wall of the wing lamina, ColI (1959), Fujita (1963) and by Hinds' ultrastructural gradually disappears to form the posterior septus on the studies (1971). median line. The remaining portion of the cavity gradual Neuroblasts originate from the pluripotent cells of the ly transforms into the central canal of the spinal cord. ventricular area and are destined to various layers of the In cross-sections we can distinguish three layers in the cerebral cortex and to the medullary neuroblasts. Fur spinal cord. Peripherally and under the meningeal sheath ther insight into cellular dynamics, the differentiation there is a white thin layer called the marginal veil which and maturity of distinct groups of cells present in the at first appears as a thin border corresponding to the adult spinal cord and the behaviour of neuroblasts have external surface of the fundamental and wing laminae. 3 A. Pansini et al. Spinal Meningiomas © Springer-Verlag Italia 1996