Nonvestibular schwannomas of the brain: a 7-year experience

Nonvestibular schwannomas are uncommon tumors of the brain. Trigeminal nerve schwannomas are the most common of this group, followed by glossopharyngeal, vagal, facial, accessory, hypoglossal, oculomotor, trochlear, and abducens nerve schwannomas, in descending order of frequency. We present a series of nonvestibular schwannomas that were surgically treated during a 7-year period.

Forty-six patients with schwannomas of Cranial Nerves V (26 cases), VII (7 cases), IX, X, and XI (9 cases), XII (3 cases), and III (1 case) were microsurgically treated by the senior author (LNS) during a 7-year period, from 1993 to 2000. The clinical presentations, operative approaches, complications, and results were studied.

Forty-five patients underwent gross total tumor resection in the first operation. One patient who had undergone subtotal tumor resection in the initial operation experienced a large recurrence after 4 years, and gross total tumor resection was achieved in the second operation. There were no postoperative deaths. Postoperative morbidity consisted of cerebrospinal fluid leaks for 5 patients (3 patients required a second operation to repair the leak, and 2 patients responded to lumbar drain placement), meningitis for 3 patients (2 cases were aseptic and 1 involved bacterial meningitis, which resolved with antibiotic therapy), vasospasm requiring angioplasty for 1 patient, temporary hemiparesis for 2 patients (who experienced good recoveries), and permanent hemiparesis for 1 patient. New cranial nerve deficits were observed for 24% of patients but were usually partial. The mean follow-up period was 33.3 months (range, 0.2-93 mo). No patient experienced tumor recurrence after complete tumor removal. The patient who experienced regrowth of the tumor did not exhibit recurrence after the second operation. The Karnofsky Performance Scale scores at the latest follow-up examination were 80 or more for 45 patients (98%) and 70 for 1 patient.

Nonvestibular schwannomas can be treated via microsurgical excision, with excellent functional results. Recurrence is rare after total tumor excision, although much longer follow-up monitoring is required.