Oct 4, 1994 - mon tumor in the cerebellopontine angle, accounting for. 10% to 15% of neoplasms in ... posterior surface of the petrous bone, clivus, and foramen magnum. ..... benign intracranial meningioma: Late recurrencerate and fac-.
Essam A. Saleh, M.D., Abdel Kader Taibah, M.D., Vittorio Achilli, M.D., Miguel Aristegui, M.D., Antonio Mazzoni, M.D., and Mario Sanna, M.D.
Posterior Fossa Meningioma:
Surgical Strategy
Posterior fossa meningioma is the second most comin the cerebellopontine angle, accounting for 10% to 15% of neoplasms in this area.1 2 Unlike acoustic neuroma, posterior fossa meningioma presents a real surgical challenge. A relatively higher morbidity and mortality have characterized the different series presented in the literature when compared to acoustic neuromas.3-5 The variable location of these tumors, their usually large size at diagnosis, their frequent encroachment on neural and vascular structures, and their potentially invasive behavior are some of the criteria that make the resection of these lesions a difficult task. Castellano and Ruggiero' classified posterior fossa meningiomas according to their site of dural implant into five groups-namely, cerebellar convexity, tentorium, posterior surface of the petrous bone, clivus, and foramen magnum. Desgeorges et a16 adopted this classification and further divided the posterior surface of petrous bone meningiomas according to the exact site of implant in relation to the internal auditory canal (IAC) and labyrinth into an anterior group, a median group (centered on the IAC), mon tumor
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and a posterior group. En plaque meningiomas have a wide base of implant and involve all zones. We utilize both classifications but further distinguish a particular type in which meningiomas are basically centered on the jugular foramen. Out of 648 posterior fossa tumors managed in our centers 40 cases were meningiomas, constituting about 5.6% of our cases. The aim of this report is to present our strategy in the management of posterior fossa meningiomas based on our experience in treating these cases.
MATERIALS AND METHODS The charts of all the patients with posterior fossa meningiomas managed in our centers between the years 1985 to 1993 were reviewed. The clinical features, diagnostic approach, operative procedures, postoperative outcome, and clinical and radiological follow-ups were studied. Operative videotapes were also reviewed when necessary.
Skull Base Surgery, Volume 4, Number 4, October 1994 Department of Otolaryngology, Alexandria University, Alexandria, Egypt (E.A.S.), Gruppo Otologico, Piacenza, Italy (E.A.S., A.K.T., M.A., M.S.), Department of Otolaryngology, Ospedale Riuniti, Bergamo, Italy (V.A., A.M.), and Servicio de ORL, Hospital Central Cruz Roja, Madrid, Spain (M.A.) Part of this work was presented at the 1st Congress of the European Skull Base Society, September 26-30, 1993, Riva del Garda, Italy This work was supported by a grant from the Associazione Italiano Neuro-Otologica Reprint requests: Dr. Sanna, Gruppo Otologico, Via Emmanueli 42, 29100 Piacenza, Italy Copyright C 1994 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
POSTERIOR FOSSA MEN INGIOMA-SALEH ET AL
There were 40 cases, of whom 30 (75%) were females and 10 (25%) were males. Their age ranged from 17 to 77 years with a mean of 50 years.
RESU LTS Otologic symptoms were the most frequent complaints at the time of diagnosis. Table 1 lists the different clinical features in these patients. Audiometry revealed normal or mild sensorineural hearing loss in 16 cases (40%), moderate sensorineural hearing loss in 5 cases (12.5%), severe sensorineural hearing loss in 11 cases (27.5%), and profound sensorineural hearing loss in 7 cases (17.5%). One case (2.5%) showed moderate conductive hearing loss. An auditory brain stem response test was performed in 18 cases; response was normal in 6 (33%) and pathologic for retrocochlear pathology in 12 (67%) cases. Radiological investigations included comTable 1. Clinical Manifestations of Patients with Posterior Fossa Meningioma (n = 40) Manifestation Number Hearing loss 22 (55%) 20 (50%) Disequilibrium Tinnitus 19 (47.5%) 11 (27.5%) Trigeminal anaesthesia 3 (7.5%) Trigeminal neuralgia 3 (7.5%) Headache Facial palsy 3 (7.5%) Diplopia 3 (7.5%) Ataxia 3 (7.5%) 2 (5%) Dysphonia-dysphagia Gait disturbance 1 (2.5%)
Figure 1. Magnetic resonance imaging with gadolinium enhancement (saggital view) showing an extensive posterior fossa meningioma (arrows) extending from the petroclival region through the foramen magnum to the neck.
puted tomography in 18 cases, magnetic resonance imaging in 3 cases, and both modalities in 19 cases. Angiography was performed in 20 cases, with preoperative embolization performed in 4. Preoperative diagnosis was obtained in 31 cases (77.5%) and was suspected in another 2. In the remaining patients, a preoperative diagnosis of acoustic neuroma was made in 6 cases and a facial neuroma was suspected in 1 case. Forty-two surgical procedures were performed in 39 patients. One patient has an en plaque meningioma involving the petrous bone and extending to the neck as evidenced with magnetic resonance imaging (Fig. 1). This patient is asymptomatic apart from profound ispilateral deafness and is undergoing regular follow-up and watchful expectancy. In 3 patients complete tumor removal was accomplished in two stages. The remaining patient is scheduled for a second-stage removal of a residual supratentorial component of a petroclival meningioma. Singlestage total tumor removal was grossly accomplished in all the other cases as ascertained by postoperative computed tomography or magnetic resonance imaging. Three cases presented with recurrences following surgical procedures performed elsewhere. Tumor size measured as the largest tumor diameter as seen on computed tomography or magnetic resonance imaging ranged from 5 mm to 7 cm with a mean of 3.4 cm. Three cases had en plaque meningiomas involving the clivus, petrous bone, IAC, middle ear, jugular foramen, and lateral border of the foramen magnum and extending to the neck. Table 2 illustrates the different locations of the tumors.
Eighteen cases (43%) were approached by the translabyrinthine (TL) approach (Fig. 2). The modified transcochlear (TC) approach7,8 (Fig. 3) was performed in 11
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Tumor Site IAC
Petroclival Posterior to IAC
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Table 2. Location of Posterior Fossa Meningioma (n = 40) Number of Cases Small Tumor Medium Tumor Large Tumor (< 1 cm) (1-2.5 cm) (>2.5 cm) 2 5 8 9 5
Jugular foramen En plaque
2
Anterior to IAC Tentorial Total 2 (5%) = IAC interior auditory canal. *Three cases had supratentorial extension. tTwo cases were attached to the sigmoid sinus dura.
2
9 (22.5%)
2 3 2 29 (72.5%)
15 9 5 4 3 2 2 40
Total (37.5%) (22.5%)* (1 2.5%)t (10%) (7.5%) (5%) (5%) (100%)
Figure 2. A: Computed tomography (CT) scan with contrast showing a left 7-cm meningioma lying posteriorly to the internal auditory canal. The patient had a preoperative ipsilateral severe sensorineural hearing loss. B: Postoperative CT scan of the same patient showing total tumor removal through a translabyrinthine approach.
POSTERIOR FOSSA MENINGIOMA-SALEH ET AL
A
Figure 3. A: Magnetic resoimaging with gadolinium showing a large right petroclival meningioma crossing the midline. B: Computed tomography (CT) scan with contrast of the same patient at a higher axial cut showing supratentonial tumor extension. C: Postoperative CT scan of the same patient demonstrating total removal of the infratentorial component of the tunance
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mor via a modified tran scoch lear ap-
proach. A second stage is planned for removal of the supratentorial part.
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cases (26%). Besides uncovering the IAC, posterior re- moval of the neck extension of two patients (5%) with en routing the facial nerve, and drilling the cochlea, the plaque tumors (Fig. 5), and a subtemporal transtentorial modified TC approach entails removing the external audi- approach for a supratentorial residual tumor in the remaintory canal wall, closing it as a cul de sac, and drilling the der (2%). The surgical approaches used for different petrous apex and middle clivus. The petro-occipital trans- tumor locations are shown in Table 3. Many cases showed some degree of dural and bone sigmoid (POTS) approach9 (Fig. 4) was performed in 5 cases (12%) and the suboccipital (SO) approach in 4 cases invasion by the tumor as proven by histopathologic exam(10%). In 1 case (2%) a POTS transtentorial approach was ination. Massive bone involvement was evident in five done. In 3 cases where a modified transcochlear approach cases. New cranial nerve deficits constituted the main posthad been performed, a planned second-stage procedure was undertaken for total tumor removal. This included operative morbidity in this series. This included paralysis POTS combined with a transcervical approach for re- of cranial nerves IX and X in five cases, with evidence of
Figure 4. A: Magnetic resonance imaging with gadolinium illustrating a right posterior fossa meningioma in the region of the jugular foramen. B: Postoperative computed tomography scan of the same patient showing total tumor removal through a petro-occipital transsigmoid ap206
proach.
POSTERIOR FOSSA MEN INGIOMA-SALEH ET AL
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cochrerappa. TiiMagnesc (conalce w).FmatnoblIteratinthe jaopanium i ustratin g a huge left en plaquesida extracranltuo cnl meningioma extenuing ally down to the level of upper borr vertebra. B: MRI of the de of C-2 6 monthsafter theecond same patient firstth nec in~_ a(arw) small tumor~~~~~~~~~ by modifiedA_transncs stage removal cochlear approach. Tl images (coronal view). Faton ofera-t_theower c can be Note tive cavity seen. residual aifiat c tumor in the neck (arrows). A small residual intracranial tumor can also be seen (white arrow). C: Computed tomography (CT) scan of the iJ_
