Acoustic Tumor Surgery and Tinnitus.

A total of 311 patients with a unilateral acoustic neurinoma were operated on via the enlarged middle cranial fossa approach. A total tumor removal was achieved in 98% of cases. The mortality was 0.6%. Overall in acoustic neurinoma surgery, the percentage rates of meningitis (1.6%), cerebrospinal fluid fistula (1.6% requiring surgery), and neurological deficits were fairly low. The facial nerve could be preserved anatomically in 99%. A House I or House II classification was demonstrated in 91% of all tumors and in 98% of small- and medium-sized tumors. Preservation of the hearing function was possible in 49% of all patients (71% in small tumors). A positive effect on tinnitus usually occurred in 45% of cases. The enlarged middle cranial fossa approach allows function-preserving surgery of the cranial nerves (e.g., the facial and cochlear nerves) and cerebral structures, even including total removal of large acoustic neurinomas of up to 3-4 cm.