Hearing preservation rates after microsurgical resection of vestibular schwannoma

Preservation of hearing is a major goal of surgery for patients with vestibular schwannoma (VS). We performed an analysis of the published literature on hearing outcome after microsurgery for VS. Our objective was to provide a comprehensive and unbiased description of published results. We completed a comprehensive search of the English language literature, most recently in October 2009, and identified a total of 62 studies publishing disaggregated hearing outcome data of patients undergoing microsurgical resection of VS. Inclusion criteria for articles were: (i) hearing preservation rates were reported specifically for VS; (ii) hearing status was reported using the American Association of Otolaryngology-Head and Neck Surgery (AAO-HNS) or Gardner-Robertson (GR) classification; and (iii) initial tumor size was documented. We performed a multivariate step-wise logistic regression based on the results of univariate analysis, to determine factors which significantly impacted rates of hearing preservation in these patients. Of these, 49 articles involving 998 patients presented disaggregated data regarding the outcomes of individual patients, and were included in our analysis, with an over-all hearing preservation rate of 52%. In total, 286 patients underwent surgery by the middle cranial fossa (MCF) approach, and 702 patients underwent surgery via the retrosigmoid (RS) approach. The follow-up in these series ranged from 6months to 7years. Rates of hearing preservation in general declined with increasing age and tumor size. Patients undergoing surgery via the MCF had better hearing outcomes on univariate analysis than those undergoing the RS approach (63% vs. 47%, p<0.0001). Multivariate analysis found that tumor size >1.5cm (odds ratio [OR] 2.81, 95% confidence interval [CI]=1.59-4.95, p<0.001), and the RS approach (OR 4.15, 95% CI=1.97-8.77, p<0.001) were independent significant risk factors for loss of serviceable hearing during VS surgery. Use of the MCF demonstrates superior hearing outcomes to the RS approach, even after correcting for the effect of the increased size of tumors addressed by the RS approach.