Preoperative predictive factors for hearing preservation in vestibular schwannoma surgery

Objectives: We performed a retrospective chart review to evaluate the various predictive factors for postoperative hearing preservation in the surgical management of vestibular schwannoma. Methods: Of 792 patients operated on for vestibular schwannoma between April 1987 and July 2002. 107 were candidates for hearing preservation surgery. These patients were divided into group I (hearing preserved) and group 2 (hearing not preserved), and both of these groups were evaluated for age, sex, pure tone average, sound discrimination score, tumor size, and auditory brain stem response parameters. A corrected chi(2) test and a corrected t-test were used for statistical analysis. Multiple regression analysis was further done to evaluate independent predictive factors. either alone or in combination. The results were evaluated by use of the modified Sanna classification and the guidelines of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS). Results: Preoperative pure tone average and tumor size were the 2 predictive factors in our study. A Pearson correlation test showed that there was no multicollinearity between the factors. On multiple regression analysis by backward elimination of nonsignificant factors, we found that tumor size is an independent predictive factor for postoperative hearing. According to the modified Sanna classification, postoperative hearing was preserved in 11.2% of patients (equivalent to class A of AAO-HNS guidelines). Conclusions: In our series, preoperative pure tone average and tumor size were found to be predictors of postoperative hearing levels.