Trigeminal schwannoma. Surgical series of 14 cases with review of the literature

A consecutive series of 14 patients with trigeminal schwannoma managed surgically at the Neurological Institute of New York since 1970 is reported. Nine women and five men (mean age 40 years) were diagnosed following a mean symptom duration of 33 months. Abnormalities of trigeminal nerve function were present in 11 patients on admission examination. Facial pain was a prominent feature in eight patients. Two patients, both with schwannomas arising from the trigeminal root, presented initially with typical trigeminal neuralgia. Additional cranial nerve palsies or cerebellar or pyramidal tract signs were noted in eight patients. The surgical approach to these tumors depends on their anatomical location. Four patients had tumors confined to the middle fossa, three patients had tumors limited to the posterior fossa, and seven patients had both supratentorial and infratentorial components of their tumors. Twenty operative procedures were performed on these patients, resulting in complete extirpation in six patients, nearly complete removal in seven patients, and partial removal in one patient. Adherence of the tumor to the lateral wall of the cavernous sinus or the brain stem precluded total removal. There was one postoperative death. In the immediate postoperative period, abnormalities of cranial nerves controlling the extraocular muscles were common. In general, these deficits were transient; however, some permanent loss of trigeminal nerve function occurred in nine patients. Two patients required tarsorrhaphy for neurotropic keratitis, and two patients underwent cerebrospinal fluid (CSF) shunting procedures for hydrocephalus or for a persistent CSF leak. The follow-up period ranged from 4 to 177 months (mean 47 months). The clinical features, anatomical considerations, and surgical approach to these rare tumors are discussed. A clinical review of 106 additional cases of trigeminal schwannoma, reported in the English literature since 1935, is also presented.