Large sphenocavernous meningiomas: Is there still a role for the intradural approach via the pterional-transsylvian route?

Acta Neurochir (2003) 145: 273–282

DOI 10.1007/s00701-003-0003-8 Acta NeurochirurgicaPrinted in Austria

Clinical ArticleLarge sphenocavernous meningiomas: Is there still a role for the intraduralapproach via the pterional-transsylvian route?*

F. Tomasello, O. de Divitiis, F. F. Angileri, F. M. Salpietro, and D. d’Avella

Neurosurgical Clinic, Department of Neurosciences, Psychiatric and Anesthesiological Sciences University of Messina, Messina, Italy

Published online April 28, 20036 Springer-Verlag 2003

Summary

Background. Large-sized sphenocavernous meningiomas repre-

sent a surgical challenge. Although the role of skull base techniques

with combined extra- and intradural steps has been recently empha-

sized, pure intradural resection tactics via the pterional route consti-

tute the traditional microsurgical approach for resection of such

tumours.

Method. We report the application of the pterional-transsylvian

approach in 13 patients with sphenocavernous meningiomas. This

series is unique because it includes only patients with tumours ex-

ceeding 5 cm in their greatest dimension.

Findings. A gross total resection was accomplished in 10 patients

(77%). Eight patients had a good outcome, one had a persistent mild

hemiparesis, and one died. No recurrences occurred in this group.

Three patients (23%) had subtotal resections owing to invasion of the

cavernous sinus in one instance and encasement of the middle cere-

bral artery in the others. Two had a good outcome and one died. In

these patients minimal asymptomatic tumour progression was seen 3

and 6 years after surgery. The overall surgical outcome was good in

10 patients (77%), fair in one, and death in two.

Interpretation. In our experience, large sphenocavernous menin-

giomas may be operated on adopting pure intradural resection

tactics via the pterional-transsylvian route with rates of gross total

removal and surgical complications related to brain retraction

or vascular manipulation comparable to those of extensive skull

base approaches. The traditional intradural pterional trans-

sylvian approach continues to have a place in the treatment of these

lesions.

Keywords: Surgical approach; meningioma; skull base surgery;

cavernous sinus.

Introduction

Sphenocavernous meningiomas, arising from the

dura covering the medial portion of the sphenoid bone,

occupy the region of the anterior clinoid and adjacent

medial sphenoid wing and involve the pericavernous

or cavernous sinus structures [16, 24]. These tumours

are di¤erentiated from clinoidal meningiomas on the

basis of their dural attachment, growth pattern, neu-

rovascular relationships and clinical presentation. Tu-

mours with an ‘‘en masse’’ [3, 4] growth pattern may

attain surprisingly large size with relatively minimal

symptoms. Such huge (b5 cm in diameter) meningi-

omas still represent a surgical challenge.

Recent reports have emphasized the role of con-

temporary skull base surgical techniques with com-

bined extra- and intradural steps for resection of large

sphenocavernous meningiomas [2, 9]. Nevertheless,

the ‘‘pure’’ intradural resection tactics via the pterional

route, that are the traditional microsurgical approach

to these lesions, can result in excellent outcomes after

operation [3, 4, 5, 10, 16, 24]. Very large tumours,

however, were not specifically considered in these

publications. This paper describes the application of

the pterional transsylvian approach in 13 patients who

had a sphenocavernous meningioma, larger than 5 cm

in the greatest dimension. The aims of this article are:

1) to consider specifically the issue of suitability of the

intradural pterional-transsylvian route for large-sized

sphenocavernous meningiomas; and 2) to investigate

if this approach contributes to minimizing morbidity

after operation.* This paper was supported in part by Grant ‘‘Piano B008 – P.R.

2’’ from M.U.R.S.T. and European Community.

Patients and methods

Clinical presentation

Thirteen patients harbouring a large-sized sphenocavernous men-

ingioma were operated on by the senior author (F.T.) between June

1988 and June 2000 at the Neurosurgical Clinic of the University of

Messina School of Medicine in Messina, Italy. They were 11 women

and 2 men with a mean age of 57.6 years (range 43 to 71 years). The

clinical records, neuroradiological examinations, and operative

notes and videotape recordings of the procedures of these patients

were examined retrospectively. Signs on presentation consisted of

chronic headache present in eight of thirteen patients (61.5%), sei-

zures in eight (61.5%), visual acuity or visual field impairment in

three (23%), and altered mental status and personality changes in

four (30.7%) (Table 1). The beginning of symptoms preceded diag-

nosis by 3 to 36 months (average 14.6 months). No patient was

admitted in comatose condition requiring emergency craniotomy.

Fourteen operations were performed in thirteen patients. Karnofsky

performance status was taken as a gross measure of neurological

functional impairment [13]. When graded preoperatively, Karnofsky

index averaged 70% (range 60 to 90%). Post-operative clinical and

neuroradiological follow-up periods ranged from 12 to 156 months

(average 48.3 months).

Preoperative neuroradiological findings

All but one patient (in whom a contrast-enhanced CT scan was

obtained) underwent sequential contrast-enhanced magnetic reso-

nance imaging (including T1 weighted, T2 weighted, spin-echo and

gradient echo multiplanar images), preoperatively, in the early post-

operative period, and at subsequent follow-up examinations (6–12

months postoperatively and when this series was reviewed for publi-

cation purposes). Preoperative MR images were evaluated for tu-

mour size, direction of growth in anterior and middle cranial fossa,

cavernous sinus involvement, involvement of the carotid, anterior

and middle cerebral arteries as well as the optic apparatus, and de-

gree of perilesional oedema. The tumour’s maximum diameter was

measured and found to be greater than 5 cm in all cases (mean

5.7 cm). The largest tumour of this series reached 7 cm in maximum

diameter (Fig. 1). The cavernous sinus structures were clearly in-

vaded in one case while in the others the tumour appeared to be only

adherent to the sinus lateral wall. The tumour never extended into

the sella turcica. The carotid artery, the carotid bifurcation and the

A1 and M1 segments were engulfed by the tumour in all patients as

confirmed by cerebral DSA which was obtained in all cases. Tumour

embolization was performed only in one patient in whom the exter-

nal carotid artery contribution to meningioma vascularization

appeared particularly dominant. The extent of perilesional oedema

was graded as severe in ten cases (83%) (Fig. 2) and moderate in

three cases. In all cases it was of the di¤use type [19].

Postoperative magnetic resonance evaluation

The post-operative early-phase MR images were examined for

extent of tumour removal, postoperative sequelae, and the presence

of additional oedema or vascular congestion. Standard late follow-

up MRI served to confirm completeness of excision and lack of re-

currence. Studies were supplemented by obtaining fluid attenuated

inversion recovery (FLAIR) sequences to evaluate postoperative

changes in the brain parenchyma. FLAIR sequences were performed

according to the scanning parameters reported by Tsuchiya et al. [22]

and other reports from our group [6]. Parameters examined included

evidence of permanent parenchymal alterations, including degener-

ative changes or tissue gliosis, and persistence of areas of white mat-

ter oedema. These changes were examined in regions of interest of

the frontal and temporal lobes ipsilateral to the operative approach.

Operative technique

The patient is placed supine with shoulder ipsilateral to the

approach slightly elevated and the head fixed in the Mayfield head-

Fig. 1. Case 2: preoperative magnetic resonance images with contrast enhancement: (A) coronal and (B) axial planes showing a large sphe-

nocavernous meningioma in a 63 years old woman who presented with headache and short-term memory impairment

274 F. Tomasello et al.

rest and turned 45� to the opposite side. The skin incision, the tem-

poralis muscle preparation, and the bony steps are performed as for a

standard pterional craniotomy, including extensive drilling of the

sphenoid wing and temporobasal craniectomy. In this step, care must

be taken to identify and coagulate the deep branches of the middle

meningeal artery (e.g. orbito-meningeal artery and its branches) al-

lowing partial devascularization of the tumour. After opening the

dura the sylvian fissure is dissected and widely opened. This allows

elevation of the basal posterior aspect of the frontal lobe with mini-

mal retraction pressure, also as a consequence of the upward dislo-

cation of the frontal lobe exerted by the tumour itself. The capsule is

coagulated and incised and the tumour partially debulked with the

aid of the ultrasonic aspirator. Central tumour enucleation is alter-

nated to coagulation of the feeding vessels at the base of the tumour

along the sphenoid ridge, as well as control and coagulation of lep-

tomeningeal feeding arteries. Tumour devascularization results in

reduction in turgor and consistency and facilitates its debulking. Be-

cause these large tumours grow massively into the sylvian fissure,

dissection commences at a more distal point. The branches of the

sylvian artery are identified and the artery is followed proximally to

establish a dissection plane. This manoeuvre allows a better spatial

identification of the seeming ‘‘intratumoural’’ position of the encased

vessels. The tumour is removed in a piecemeal fashion under strict

visual control of the middle cerebral artery and its branches, which

can be shifted, stretched, or encased. In the latter case the tumour

may remain separated from the arteries by an arachnoid layer, which

facilitates dissection, conducted either with sharp instruments or

blunt dissection. During this phase small arterial branches from the

internal carotid artery nourishing the tumour are coagulated and

divided. When enough tumour volume reduction has been achieved,

the proximal (paraclinoid segment) carotid artery, the optic nerve,

and the cisternal portion of the III cranial nerve are recognized and

dissected free from the tumour. After control of the paraclinoid ICA

is gained, dissection of the MCA and its perforating branches, and

the posterior communicating and anterior choroidal arteries can be

completed. The base of the tumour can now be fully exposed and

devascularization completed. The invaded dura is coagulated and

resected. The dissection is finally carried out on the lateral wall of the

cavernous sinus, peeling the walls with sharp instruments and com-

pleting tumour removal with cautious bipolar coagulation. In only

one case the lateral wall barrier was frankly crossed by the tumour.

In such instances we intentionally follow a predetermined strategy

aimed at removing the extracavernous portion of the tumour and

preserving anatomic continuity and existing function of cavernous

sinus vascular and nervous structures [15].

Results

Clinical features and outcome

The salient aspects of each patient’s peri- and post-

operative course are summarized in Table 1. A gross

total resection (defined as grade II according to De

Monte tumour removal grading system) [8] (Table 2)

was accomplished in 10 patients (77%) who underwent

eleven operations. In all cases the surgeon’s impres-

sion was confirmed by postoperative MR studies.

Eight patients had a good outcome, 1 patient had a

mild persistent left hemiparesis and 1 patient died from

pulmonary embolism after she had recovered from

anaesthesia and appeared neurologically intact. No

recurrence was identified at late clinical and neuro-

radiological follow-up examinations in this group of

patients. Three patients (23%) had subtotal resections

Fig. 2. Case 7: (A) pre-operative axial T2 weighted magnetic resonance images showing severe peritumoural edema (di¤use type). (B) Post-

operative scan at six months follow-up demonstrating complete resolution of the oedema

Large sphenocavernous meningiomas: Is there still a role for the intradural approach via the pterional-transsylvian route? 275

(defined as grade IVa in De Monte grading system)

owing to invasion of the cavernous sinus in one in-

stance and encasement with frank tumoural infiltra-

tion of the MCA trunk in the others. Of these patients,

one died from a surgical complication and 2 had a

good outcome. In these patients, minimal asympto-

matic tumour progression was seen 3 and 6 years after

surgery, respectively (Figs. 3, 4). No patient received

post-operative radiotherapy. Karnofsky performance

status graded 6 months postoperatively averaged 90%

(range 70 to 100%). The overall surgical outcome was

good in 10 patients (77%) who had resumed indepen-

dent activity by 3 months after surgery, fair in one

patient, and death in two. Seven patients (53.8%)

required blood replacement in the perioperative time.

The mean amount of blood replaced was 208 cc. There

were no permanent cranial nerve deficits; however,

three patients experienced a transient III nerve palsy

that had recovered completely three months after

surgery.

Magnetic resonance imaging investigations

In the total removal group, early post-operative

studies revealed no evidence of a surgical complication

and confirmed completeness of excision (Figs. 5, 6).

Lack of recurrence was documented by late follow-up

contrast-enhanced MR scans, also demonstrating no

evidence of any significant structural change and the

resolution of the intense perilesional oedema demon-

strated in preoperative studies. Late post-operative

changes in the frontal and temporal lobes ipsilateral to

the approach were specifically examined on FLAIR

MR sequences (Fig. 7). These lobes consistently ex-

hibited a repetitive pattern of post-operative alter-

ations, which were thought to represent permanent

parenchymal gliosis. It should be noted, however, that

the extent of such structural alterations was limited

and that they did not result in specific functional mor-

bidity in the present series.

Table 1. Summary of thirteen patients with sphenocavernous meningiomas

Case n�, age,

sex

Symptoms on admission Max

dimension

(cm)

Surgical

approach

Extent of

resection (De

Monte Grade)

Outcome Follow-up

(months)

Case 1 58/F headache, visual deficit, seizures 5.3 left pterional IVa, II1 Good 156 (*)

Case 2 63/F headache, short term memory impairment 7 left pterional II Died2 N/A

Case 3 62/M headache, seizures 5.4 right pterional II Good 96

Case 4 45/F intracranial hypertension 5 right pterional IVa Fair 88

Case 5 66/M headache, frontal syndrome, seizures 6 left pterional IVa Good 53

Case 6 69/F headache, visual deficit 6 left pterional II Good 39

Case 7 46/F frontal syndrome 5 left pterional II Good 21

Case 8 43/F headache, seizure 5.2 right pterional II Good 21

Case 9 52/F seizure 6.6 left pterional IVa Died3 N/A

Case 10 67/F seizure 5 left pterional II Good 18

Case 11 71/F headache, visual deficit 6 left pterional II Good 15

Case 12 54/F seizure, frontal syndrome 6 left pterional II Good 12

Case 13 58/F headache, seizure 6.5 left pterional II Good 12

1 Recurrence 3 years later, 2nd operation, total resection with a good outcome. 2 Pulmonary embolism 2 days after surgery. 3 Surgical com-

plication (*) Time length from the second operation in 1991.

Good: return to previous occupation; Fair: no major neurological deficit, but not able to return to previous occupation.

Table 2. De Monte tumour removal grading system [8]

Grade Definition

I complete microscopic removal of tumour and dural

attachment with any abnormal bone

II complete microscopic removal of tumour with diathermy

coagulation of its dural attachment

IIIa complete microscopic removal of intra- and extradural

tumour without resection or coagulation of its dural

attachment

IIIb complete microscopic removal of intradural tumour

without resection or coagulation of its dural attachment

or of any extradural extension

IVa intentional subtotal removal to preserve cranial nerves or

blood vessels with complete microscopic removal of

attachment

IVb partial removal leaving tumour < 10% in volume

V partial removal leaving tumour > 10% in volume, or

decompression with or without biopsy


Discussion

In this era of microneurosurgical technique refine-

ments, excellent surgical results can be achieved in ex-

cising skull base meningiomas. However, meningi-

omas arising from the medial sphenoid ridge with

involvement of the lateral wall of the cavernous sinus

or invasion of the sinus itself, and achieving very large

size, still represent a surgical challenge.

According to Yasargil [24] sphenocavernous men-

ingiomas are a distinct subgroup of medial sphenoid

meningiomas. Day [9] defined sphenocavernous men-

ingiomas as those arising from the dura covering the

sphenoid ridge, with or without invasion of the peri

cavernous and cavernous sinus structures. This classi-

fication is important from the nosographic point of

view, and has clinical implications. Sphenocavernous

meningiomas are distinguished from medial sphenoi-

dal meningiomas originating from the superior and/or

lateral aspect of the anterior clinoid process [2]. Due to

their growth pattern, clinoidal meningiomas are char-

acterized by an earlier involvement of the optic nerve

Fig. 3. Case 4: (A) pre-operative contrast-enhanced CT scan of a large sphenocavernous meningioma. (B and C) Contrast-enhanced follow-up

CT scans obtained at 4 and 6 years post-operative respectively. Note the minimal progression of the residual tumour embedding the MCA

trunk. Due to the asymptomatic course this patient was treated conservatively

Fig. 4. Case 5: Coronal T1 weighted contrast-enhanced magnetic resonance images showing: (A) pre-operative appearance of a large sphe-

nocavernous meningioma; (B) its follow-up enhanced MRI scan at 6 months and (C) 3 years follow-up. Note the minimal progression of the

residual tumour into the cavernous sinus. Due to the asymptomatic course this patient was treated conservatively


and proximal carotid artery. In contrast sphenoca-

vernous meningiomas tend to spread lateral-inferiorly

into the middle cranial fossa so that ICA and optic and

oculomotor nerves are generally involved later. This

di¤erence may explain the huge dimensions they may

attain before becoming symptomatic. For example,

while visual disturbances were present in 84% of cases

of clinoidal meningiomas reported by A1-Mefty [2],

only 3 of our 13 patients (23%) had visual impairment.

The foregoing anatomical, radiological and clinical

considerations, lead us to suggest the use of the term

sphenocavernous meningiomas should be reserved for

this particular subgroup of lesions.

Literature review

The pterional approach followed by intradural de-

bulking and microsurgical resection of the tumour is

the most widely used surgical route for large-sized

meningiomas of the middle cranial base. The standard

pterional intradural approach for the removal of such

tumours has been comprehensively described by Do-

lenc [10], Bonnal [3], Ojemann [16], and systematically

adopted by Yasargil [24]. The advantages and dis-

advantages of this surgical strategy have been recently

discussed and compared with those o¤ered by con-

temporary cranial base surgical techniques in a paper

reporting six patients with large sphenocavernous

meningiomas [9]. The present report presents our ex-

perience using the pterional-transsylvian route fol-

lowed by intradural microsurgical tumour resection in

a selected series of thirteen patients with a large sphe-

nocavernous meningioma. To our knowledge, this

series is the largest in the literature that specifically in-

cludes only patients with a sphenocavernous meningi-

oma larger than 5 cm diameter. A gross total removal

was achieved in 77% of patients and 77% resumed an

independent life, with marked improvement in their

neurological symptoms.

It is well known that the likelihood of unsatisfactory

surgical results and of failure to achieve complete

removal increases when a tumour is larger than 3 cm

[1, 21]. When compared to the results in published

series of Sphenocavernous meningiomas, the results

from the present series support the suitability of the

intradural approach, via the pterional-transsylvian

route, for resection of such large-sized meningiomas

(Table 3). In 1979 Dolenc reported on 10 patients who

had been operated upon via a bifrontal approach (in 2

cases) or a pterional approach (8 cases). Two deaths

occurred, 2 patients developed a transient IIIrd nerve

paresis, and four patients experienced a transient

hemiparesis. Nevertheless, the final outcomes were

good for these 8 patients [10]. In 1991 Bonnal pre-

sented 15 patients with an en masse sphenocavernous

meningioma; eight of these patients had slight or

Fig. 5. Case 7: (A) pre-operative coronal T1 weighted magnetic resonance images with contrast enhancement showing a large sphenoca-

vernous meningioma (max diameter 5 cm). (B) Post-operative scan at six months follow-up demonstrating complete excision of the lesion (De

Monte grade II)


severe post-operative morbidity. The other seven

patients had good outcomes [3]. In 1992 Ojemann

reported 17 patients, some of whom had a clinoidal

meningioma, operated upon via a fronto-temporal

craniotomy. A subtotal removal was achieved in 14

patients and a radical subtotal removal in the remain-

ing three. The outcome was good in 16 patients. One

patient had a permanent dysphasia and hemiparesis

[16]. In his monograph (1996) Yasargil described 9

patients with ‘‘medial sphenoid’’ meningiomas oper-

ated upon via a pterional approach. Seven patients

experienced a good outcome and the other two had a

‘‘fair’’ outcome [24]. Contemporary cranial base sur-

gical techniques do have a major role in the treatment

of such tumours, particularly when a large spheno-

cavernous meningioma has extensively crossed the wall

of the cavernous sinus [11, 14, 18]. Very recently, Day

[9] reported six patients in whom an aggressive skull

Fig. 6. Case 11: (A) pre-operative coronal T1 weighted magnetic resonance images with contrast enhancement showing a large sphenoca-

vernous meningioma (max diameter 6 cm). (B) Post-operative scan at six months follow-up demonstrating complete excision of the lesion (De

Monte grade II). (C and D) Late post-operative FLAIR MR axial views. There is no evidence of permanent structural changes. The frontal and

temporal lobes exhibit circumscribed areas of hyperintense signal changes. These alterations may represent permanent parenchymal gliosis


base surgical strategy was adopted to resect a large

sphenocavernous meningioma. Extensive bone work

at the cranial base was performed in each patient. Un-

roofing of the foramina rotundum, ovale, and spino-

sum of the superior orbital fissure, and of the optic

canal, removal of the anterior clinoid process, and

elevation of the undersurface of the temporal lobe, were

performed before opening the dura. Following this

strategy, four patients had a gross total resection, and

two had only a subtotal resection as result of invasion

of the cavernous sinus or the middle cerebral artery.

Two patients experienced a transient III nerve paresis,

and two developed transient postoperative cerebral

oedema that required intensive treatment. All six pa-

tients, however, had a good outcome. The use of this

technique resulted in low blood loss during the opera-

tion and obviated the need for preoperative emboliza-

tion [9].

Technical considerations

The principal advantages claimed for aggressive

skull base approaches to these lesions include: 1) better

control of arterial blood supply to the tumour 2) wider

exposure and minimization of brain retraction 3) con-

trol of neurovascular structures at the cranial base 4)

more possibility of complete excision and hence long

term, recurrence-free tumour control. These issues de-

serve detailed discussion.

1) Interruption of its blood supply before a debulk-

ing tumour is undoubtedly a great advantage. In our

experience, however, pure intradural resection tactics

did not result in significant intraoperative blood losses

as judged from blood replacement needs. In this con-

text we emphasize that a component of the vasculari-

zation of these meningiomas is from the ICA dural and

leptomeningeal branches [23], which can be dissected

and controlled during the intradural phase of the op-

eration.

2) According to Yasargil [24], the pterional-

transsylvian approach takes advantage of those planes

and spaces naturally provided to expose the base of the

brain without significant brain retraction. Moreover,

large tumours produce large ‘‘birth’’ canals through

which atraumatic brain tissue decompression can be

performed. The most striking complication, which oc-

curred in one third of patients reported by Day, was

post-operative oedema of the temporal lobe requiring

ICU management. We agree with Dolenc [12] that

venous drainage problems, related to extradural tem-

poral lobe manipulation were probably the cause of

the brain swelling. Retraction of oedematous paren-

chyma, chronically compressed by an underlying mass

may precipitate postoperative oedema, infarction, and

intracerebral haemorrhage. This holds particularly

true with a huge meningioma. Indeed, in a previous

paper by our group we showed a positive correlation

between tumour size and extent of perifocal edemata.

A positive correlation was also found between grade

of oedema and cortical penetration [19]. Minimal re-

traction and preservation of the venous drainage are

therefore crucially important. The extradural strategy

described by Day [9] involves extensive temporal lobe

manipulation, in which the undersurface of the tem-

poral lobe is separated from the cavernous sinus wall.

In our experience, the choice of the pterional trans-

sylvian intradural approach resulted in venous drain-

age preservation and avoided frontal and temporal

lobes damage from retraction. A satisfactory preser-

vation of brain structural integrity was demonstrated

by late follow-up FLAIR MR studies. We choose this

particular sequence for its capability to show brain

tissue oedema or degenerative and gliotic components

more clearly than conventional T2-weighted and pro-

Table 3. Summary of selected published series of sphenocavernous meningiomas

Author, year N� of

patients

Approach Excision Follow-up Outcome

Cook, 1968 (5) 11 pterional, intradural 2 D, 4 SD

Dolenc, 1979 (10) 10 bifrontal, pterional 2 D

Bonnal, 1980 (3) 7 pterional intra-extradural 7 subtotal 1–13 years 3 D, 1 SD, 3 GO

Ojemann, 1992 (16) 17 pterional intradural 3 RST, 14 ST 5 (1–11) years 1 SD, 16 GO

Yasargil, 1996 (24) 9 pterional intradural 2 MD, 7 GO

Day, 2000 (9) 6 extensive extradural 2 ST, 4 T 24 months (max) 6 GO

Present series, 2001 13 pterional intradural 3 ST, 10 T 48.3 (12–156) months 10 GO, 1 MD, 2 D

RST Radical subtotal resection; ST subtotal resection; T total resection; D Death; SD severe disability; MD Moderate disability; GO good

outcome.


ton density-weighted images [22]. Its clinical usefulness

in neuroimaging has been described in regard to sev-

eral conditions [7, 22]. The frontal and temporal lobes

ipsilateral to the approach consistently showed post-

operative alterations consistent with permanent pa-

renchymal gliosis. These changes, however, were of

limited extent, were not associated with any specific

neurological morbidity, and correlated well with the

neurobehavioral outcome in this series.

3) A sphenocavernous meningioma usually spares

the paraclinoid segment of the ICA and proximal

control of this vessel can be safely achieved through a

pure intradural strategy. In our experience the optic

apparatus was frequently shifted and compressed, but

never embedded in the tumour and it was always pos-

sible to dissect it free. Although the cisternal portion of

the III nerve could be displaced, stretched, and rarely,

half surrounded by the tumour it was always possible

to dissect it free. A transient III nerve palsy was ob-

served in three patients. One patient’s investigations

showed an intracavernous component of the tumour

which was not removed. We believe with others [15,

16, 20] that, in a giant tumour in which the main part

responsible for the clinical features is extracavernous,

operation should be directed at the extracavernous

portion of the tumour.

4) None of our patients had a recurrence after

undergoing a grade II resection. One patient, who had

a subtotal resection (grade IVa), showed symptomatic

tumour progression and required reoperation. These

low rates of recurrence are based on an observation

period averaging 42.3 months.

Conclusions

Large meningiomas arising from the dura cover-

ing the medial portion of the sphenoid bone, with

or without invasion of the pericavernous and cavern-

ous sinus structures, may be operated on adopting

pure intradural resection tactics via the traditional

pterional-transsylvian route. The major indications for

this pure intradural approach are lateral growth of the

tumour into the middle cranial fossa that limits the

possibility of temporal lobe retraction, and a lack of

frank cavernous sinus invasion. In our experience, the

rates of gross total removal and surgical complications

related to brain retraction or vascular manipulation

are acceptable and not worse those reported for com-

plex extra-intradural skull base approaches. These, on

the other hand, still need validation based on long-

term follow-up evaluations for this group of meningi-

omas. We believe that the major hazards of perioper-

ative morbidity in these patients are related to the

intradural vascular and neural dissection phase, and

these steps therefore represent the most important

focus in defining the strategy for approaching these

meningiomas.

We conclude that, although contemporary skull

base approaches, with intra and extradural strategies,

represent the gold standard to approach cranial base

meningiomas, the traditional intradural pterional

transsylvian approach continues to have a role in the

treatment of selected subgroups of cranial base tu-

mours such as giant sphenocavernous meningiomas.

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Comment

This is a very well written paper on the surgical treatment of large

spheno-cavemous meningiomas. The tenor of the article appeals be-

cause the authors go back to basics and prove in a convincing way

that a well executed, straightforward pterional approach is very ef-

fective in treating these tumours. In the light of all the skull-base

surgery violence it is a relief to find an article that points out the

merits of such a time-honoured approach.

The results presented are as least as good as the results in those

studies where extensive portions of the skull-base were removed to

get better access to the tumor, enabling the surgeon to carry out a

more complete resection. In this respect the message of the paper is a

very timely one since there seems to be a tendency among skull-base

surgeons to perform much more limited resections than some years

ago, because of the often very slow growth-rate of these meningi-

ornas and because of the possibility to treat the remnant or the re-

currence by way of stereotactic irradiation.

The advice of the authors to expose the distal middle cerebral ar-

tery and its branches first before starting the removal of the tumor is

well taken. However, in my opinion it might be advisable to delay

the tumor-resection and to look for the intracranial portion of the

Internal Carotid Artery and from there to follow the Middle Cere-

bral Artery in a distal direction. The extra time spent in performing

these manoeuvres is well invested since when the operation has a

poor outcome it is in the majority of cases caused by a lesion of the

ICA or the MCA, or one of its branches.

K. Tulleken

Correspondence: Domenico d’Avella, M.D., Neurosurgical

Clinic, Department of Neuroscience, Psychiatric and Anesthesiol-

gical Sciences, Policlinico Universitario, via Consolare Valeria 1,

98122 Messina, Italy.

282 F. Tomasello et al.: Large sphenocavernous meningiomas

Large sphenocavernous meningiomas: Is there still a role for the intradural approach via the pterional-transsylvian route?

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