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African Journal of Neurological Sciences
Pan African Association of Neurological Sciences
ISSN: 1015-8618
Vol. 14, Num. 1, 1995
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The African Journal of Neurological Sciences
Vol 14 No.1, 1995
The surgery of meningiomas: a review of 215 cases
R F Ruberti
Nairobi, Kenya
Code Number: NS95003
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SUMMARY
Out of a total of 1041 verified neoplastic lesions of the
central nervous system (CNS) operated by the Author over a
period of 40 years of neuro-surgical practice in Italy and in
Kenya (this series does not include vascular malformations or
haematomas, parasitic or infectious lesions and/to cystic
arachnoiditis), 215 patients have been operated for benign
meningiomas of CNS. Meningiomas with signs of hystologic
anaplasia were excluded. Of the 215 meningiomas, 174 were
intracranial and 41 intraspinal. A critical review of the
surgical treatment of these cases is carried out.
RESUME
En 40 ans l'Auteur a opere en Italic et au Kenya 1041
tumeurs du S.N.C., sans tenir compte des realformations
vasculaire, des hematomes, des processus expansifs d'origine
infectieuse ou parasitaire ni des arachnoidites. Parmi ces
tumeurs, 215 etaient meningiomes benins a localization
intracraniens 174 lois et intraspinale 41 lois. Une revue
critique du traitement chirurgical de ces cas est exposee.
Key words: Meningiomas - Surgical treatment.
INTRODUCTION
The incidence of neoplastic lesions of the CNS constitutes
normally around 10 percent of the surgical material in a
neurosurgical practice (ZULCH). In our experience of nearly
6000 major neurosurgical operations carried out in 40 years,
the number of 1041 verified neoplastic lesions of the CNS is
the 17.5 per cent of the whole neurosurgical material. This
high incidence may be due to the high incidence of neoplastic
lesions admitted and operated in the Neurosurgical Clinic of
the University of Padua Italy, where I have worked for fifteen
years, and to the high incidence of the same lesions referred
from all over Eastern Africa to Nairobi, were I have been
working for the last 25 years.
In this series, the relative incidence of meningiomas compared
with other tumours of the CNS, was as follows:
TABLE 1
TYPE OF TUMOUR NO. OF CASES PERCENTAGE
-------------------------------------------------
GLIOMAS 474 45.5
MENINGIOMAS 215 20.6
PITUITARY ADENOMAS 81 7.8
NEURINOMAS 74 7.1
SARCOMAS 63 6.0
CRANIOPHARYNGIOMAS 46 4.4
EMBRIONIC TUMOURS 28 2.7
METASTATIC TUMOURS 27 2.6
OSTEOMAS 20 1.9
LIPOMAS 5 0.5
HAEMANGIOMAS 6 0.6
LYPHOMAS 2 0.2
The meningiomas constitute about 20 per cent of all neoplastic
lesions of the CNS in this series, more than a third of the
number of the gliomas.
The relative incidence of histopathological type of various
neoplasms of this series compared in percentage with other large
series, was as follows:
TABLE 2
Types of Tumors Cushing Olivercrona Zulch Ruberti
--------------------------------------------------------
GLIOMAS 36.6% 46.6% 43.3% 45.5%
MENINGLIOMAS 13.4 19.2 18.0 20.6
PITUITARY ADENOMAS 17.8 8.5 8.0 7.8
EMBRYONIC TUMOURS 0.9 1.0 2.1 2.7
CRANIOPHYARYNGIOMAS 4.6 1.7 2.5 4.4
NEURINOMAS 8.7 8.0 7.6 7.1
SARCOMAS 0.7 - 2.7 6.0
METASTATIC TUMOURS 3.2 3.4 4.0 2.6
OSTEOMAS 0.7 - 0.5
1.9
There are not very significant difference, except for a
slightly higher incidence in the meningiomas, a higher
incidence in the sarcomas, osteomas and embryonic tumours and
a lower incidence of neurinomas and pituitary adenomas in the
Author's series compared with those of CUSHING'S, OLIVECRONA
AND ZULCH.
MENINGIOMAS OF THE CENTRAL NERVOUS SYSTEM
Age incidence
The incidence of age per decade was as follows:
TABLE 3
YEARS OF AGE NO. OF CASES PERCENTAGE
-------------------------------------------
0 - 10 7 3.2
11 - 20 16 7.4
21 - 30 47 21.9
31 - 40 49 22.8
41 - 50 59 27.4
51 - 60 23 10.7
61 - 70 10 4.6
71 and over 4 1.8
As seen in table 3, meningiomas may occur at any age but reach
their peak of incidence in the middle age. The oldest patient
of this series was 74, the youngest was 2. The average age was
36 years. The sex incidence shows, as in other series, that
the meningiomas are commoner in female (123 cases or 57
percent) than in males (92 cases or 43 percent).
ANATOMICAL LOCATION
Although meningiomas may arise anywhere, they show a strong
predilection for some anatomical sites. The anatomical
location and the biological behaviour of the tumours lead to
the recognition of typical clinical syndromes, characteristic
for each group; these clinical features are not considered in
this paper.
From the histopathological point of view, only benign
meningiomas were included in this series, excluding the
meningosarcomas and fibrosarcomas.
a) Intracranial Meningiomas
Out of the 174 intracranial meningiomas, 165, were
supratentorial and only 9 in the posterior fossa. 43 of them
were located on the right side, 58 on the left and 73 in the
midline.
The incidence of the anatomical location of these meningiomas
as well as its percentage are compared with the same location
in cushing's series and are as follows:
TABLE 4
ANATOMICAL LOCATION NO OF CASES CUSHING'S % RUBERTI'S%
-----------------------------------------------------------
PARASAGITTAL AND FALX 52 24 30
CONVEXITY 41 18 23
SPENOIDAL RIDGE 26 18 15
OLFACTORY GROOVE 14 10 8
SUPRASELLAR 24 10 14
POSTERIOR FOSSA 9 8 5
LATERAL VENTRICLES 3 1 2
TENTORIUM 5 1 3
There are some differences between the percentage in the two
series: there is a higher incidence of parasagital, falx,
convexity, suprasellar, ventricular and tentorium meningiomas
in our series and a lower incidence of sphenoidal ridge and
posterior fossa meningiomas in our series compared
CUSHING'S.
Incidentally in our series the proportion of parasagital (38
cases) to falx (14 cases) meningiomas was 3 to one as in
McKISSOCK'S series (GAUTIER and SMITH, 1970) and not 10 to one
as in CUSHING'S series. Of the sphenoidal wing meningiomas, 15
were of the outer third, 7 of the middle third and 4 of the
inner third.
Of the meningiomas of the posterior possa, 4 were located in
the ponto-cerebellar angle, 2 in the clivus and 3 were in the
convexity.
Out of three lateral ventrical meningiomas, all were on the
left side as in the other series.
The tentorium meningiomas were all supratentorial, on being
located on the free edge of the tentorium.
B) Intraspinal meningiomas
Out of 41 cases of intraspinal meningioma, 17 were located in
the cervical spinal whilst 24 in the thoracic spine. Of the 17
cervical meningiomas, 11 were located in the upper cervical
and 6 in the middle cervical spine. In the thoracic spine 7
meningiomas were located in the upper thoracic spine, 12 in
the middle and 5 in the lower thoracic spine. No meningiomas
have been found in this series in the lumbar spine.
SURGICAL TREATMENT
The results of the surgery ofmeningiomas depends on many
factors: the size and location of the tumor, the degree of
involvement of vascular and nervous surrounding structures,
the experience of the surgeon, and his attitude to the
alternatives of total or partial extirpation. The removal of
some meningiomas is often a matter of great difficulty, mainly
in the deeply placed ones. It is in such deeply placed tumors
that the modern aids such as intravenous mannitol, lumbar CSF
drainage, controlled respiration, induced hypotension,
improved light and magnification helps in reducing and better
controlling the haemorrhage as well as improving the approach
and excision of the tumours.
Since the successful total removal of a large olfactory groove
meningioma, my first meningioma of this series operated on
the 4th of November, 1960, my policy has always been to try to
achieve a total removal of these tumours, and this for the
following reasons:
1 ) Operations on recurrent meningiomas are much more
traumatizing and often complicated by thick adhesions, with
consequent high mortality and morbidity
2) At least 90 per cent of all meningiomas can be totally
removed in one stage (rarely in two stages close to each
other) with a reasonable surgical risk, low morbidity and
relative low mortality.
By total removal it is intended that not only the tumour, but
its dural or vascular implant and any bone possibly involved
has to be largely removed. If this is not the case, and only a
doubt is left that some tumoral cells are left behind, one has
to talk of a subtotal removal because most certainly a
recurrence may occur, even at a long distance.
In my personal experience two are the golden rules for the
removal of these tumours: one is the large access to the
lesion and the second, the most important, is to interrupt as
soon as possible its blood supply.
There is no doubt that convexity, falx, lateral ventricle and
intraspinal meningiomas can be removed totally. The greatest
problem arises in the parasagital, the sphenoidal ridge,
mainly the ones of the inner third, the suprasellar and the
ones of the posterior fossa and clivus.
For those in the last group, there are rare cases where the
risk of total removal may suggest a subtotal one. The results
of surgery in this series are as follows:
TABLE 5
ANATOMICAL TOTAL SUBTOTAL MORT- RESULTS
LOCATION REMOVAL REMOVAL ALITY GOOD FAIR BAD
-------------------------------------------------------
PARASAGITTAL 34 4 3 22 10 3
FALX 14 - 1 12 1 -
CONVEXITY 41 - - 38 3 -
SPENOIDAL RIDGE 23 3 2 15 7 2
OLFACTORY
GROOVE 14 - - 13 1 -
SUPRASELLAR 22 2 2 11 5 6
POSTERIOR
FOSSA 7 2 1 6 2 -
LITERAL
VENTRICLE 3 - - 3 - -
TENTORIUM 4 1 1 3 1 -
INTRASPINAL 41 - - 16 13 2
TOTAL 203 12 10 149 43
13
A few comments on the results, although the statistics are
often complicated and of doubtful value, mainly when there are
not on very large series.
Nevertheless, out of 203 maningiomas totally removed, the
mortality rate was of 8 cases, around 4 per cent, and it has
to be mentioned that one of the eight cases, a meningioma of
the falx died of a cardiac arrest, without any connection with
the surgery. Out of 12 subtotal removal, the mortality was of
4 cases, meaning 33 per cent: it is obvious that the subtotal
removal was performed in the poor risk patients and in the
poor risk tumours. I remember that the one of these cases was
a very bad recurrence of a meningioma of the tentorium
operated elsewhere.
A relatively high mortality rate is found in the meningiomas
of the tentorium (20%), less in the suprasellar meningiomas
(8%), posterior fossa (11%) and sphenoidal ridge meningiomas
(8%).
Out of 205 survivors, 149 (73%) made a good recovery with full
working capacity, 43 patients (21%) made a fair recovery, able
to support themselves but with neurological deficits (several
of them had visual problems) 13 patients (6%) are completely
disabled.
The best prognosis for the meningiomas of the CNS is for the
meningiomas of the convexity and for the intrapinal
meningiomas. For the rest, the prognosis, as said before,
depends on many factors. It may be possible that the next
generation of neurosurgeons may achieve always a total removal
without mortality and very low mobility as has been emphasized
some years ago by GOSTA NORLEN.
And eventually the problem of the recurrence should be
mentioned. In this series a final assessment on the recurrence
is difficult to do, mainly due to the short time the patient
in Italy has been followed up: in seven years of time there
have been no recurrence. Many of the cases operated in Kenya
have gone lost in the follow up. Again, in all cases followed
up for a long period of time (twenty years) there have been
only one recurrence of a suprasellar meningioma 13 years after
surgery.
In conclusion, in the surgery of the meningiomas an aggressive
attitude towards a total removal is probably the treatment of
choice.
REFERENCES
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meningiomas of the spheniod ridge. J. Neurosurg.
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2. CHAN R.C., THOMPSON G.D. (1984) Morbidity, mortality and
quality of life following surgery for intracranial
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classification, regional behaviour, life history, and surgical
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central nervous system. Geneva: World Health Organization.
Copyright 1995 Pan African Association of Neurological
Sciences
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