Prognostic factors for hearing preservation in vestibular schwannoma surgery

Objective: To determine whether prognostic indicators for hearing preservation could he identified in patients with vestibular schwannoma undergoing middle fussa craniotomy resection. Study Design: Prospective case review. Setting: Private practice tertiary referral center. Patients: 333 patients with serviceable hearing and vestibular schwannoma resected by middle fossa craniotomy From 1992 to 1998. Main Outcome Measures: Potential prognostic indicators, including tumor size and nerve of origin, preoperative pure-tone average, speech discrimination, distortion product otoacoustic emission testing, age, auditory brainstem response (ABR), and electronystagmography. Results: Postoperative hearing near preoperative levels was attained in 167 patients (50%), with an American Academy of Otularyngology-Head and Neck Surgery Class A hearing result in 33% and a Class B result in 26%. Comparison of potential prognostic indicators between groups with hearing preserved and the group with no measurable hearing revealed significant differences in preoperative hearing, ABR, and tumor origin data. Better preoperative hearing, shorter intraaural wave V latency, shorter absolute wave V latency, and superior vestibular nerve origin were associated with higher rates of hearing preservation. Conclusions: Preoperative hearing status, ABR, and intraoperative tumor origin data were shown to be of value as prognostic indicators.