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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 ...
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ISBN 978-88-470-2262-1
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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
