Microsurgical Approach to Cerebellopontine Angle Tumors

ABSTRACT

The authors reviewed one hundred and twenty cases of cerebellopontine angle(CPA) tumors that were operated upon at the department of neurosurgery of Seoul National University Hospital between 1977 and 1987. The pathologic diagnosis of the tumors were acoustic neurinoma(66%), meningioma(13%), epidermoid(5%) and trigeminal neurinoma(5%). The age incidence was most frequent in the 5th and the 6th decades and 6.7% of cases occurred at the pediatric ages. Acoustic neurinomas were frequent in the 5th decade and on admission more than half of patients were poor clinical grades with large tumors more than 3cm in diameter(78.5%). There was good correlation between the clinical grade and tumor size on admission. All of the acoustic tumors were operated through the suboccipital transmeatal approach and total removal was possible in 73% with 5% of motality rate. Facial nerve was preserved in 62% of total removal-cases and the size of tumor was the important factor for the total removal of tumor with preservation of facial nerve. Cerebellopontine angle meningioma comprised 13% of all CPA tumors and incidence of male to female ratio was 213. Operations were performed either through retromastoid suboccipital approach or combined supra-infratentorial approach. Total temoval was possible in 67% without mortality. Six trigeminal neurinomas were locatedone in the middle fossa, one in the posterior fossa and the other four cases appearing as dumbbell shape. Total removal was possible in two cases and subtotal removal in four cases and the outcome was rather good in all cases. Pediatric CPA tumors were two each of medulloblastomas and ependymomas and one each of astrocytoma, primitive neuroectodermal tumor(PNET) and trigeminal neurinoma, Masson's hemagioendothelioma. Total removal was possible in four cases and the outcome was good in all cases.