Results of surgery following stereotactic irradiation for acoustic neuromas.

Stereotactic irradiation has been proposed as an alternative to surgical intervention for the treatment of acoustic neuromas. The authors present their experience with five patients previously treated with stereotactic irradiation who had progression of symptoms due to tumor enlargement. Intraoperatively, the tumors were severely scarred to the facial nerve. Histopathologic examination demonstrated viable cells typical of schwannomas. Two patients received auditory brainstem implants; neither received benefit from the implant. Three of the patients had House-Brackmann grade VI facial nerve function preoperatively, and all four patients with greater than 1 year follow-up had a grade VI postoperatively. It is concluded that, with stereotactic irradiation, surgical morbidity is increased, brainstem implant results are poor, and viable tumor persists.