Objective To investigate the estimated hearing preservation rates in patients who underwent retrosigmoid (RS) surgery for treatment of sporadic vestibular schwannomas (VS) through implementation of a meta-analysis based on the published hearing outcomes within the current literature.
Data Sources The PubMed, Scopus, and Embase databases were used to identify retrospective and prospective studies which involved hearing outcomes of VS patients who underwent the RS approach. The first, second, and fourth authors independently reviewed the aggregated articles and final decisions of study inclusion were dependent on consensus.
Study Selection Of 383 articles, 28 studies (7.3%) met eligibility criteria. Together, these 28 studies comprised a total of 2,088 patients with serviceable preoperative hearing in the affected ear, for whom postoperative hearing preservation could be evaluated.
Data Extraction Both preoperative and postoperative hearing grades were extracted to determine the hearing preservation rate presented in the group of patients in each article. In addition, patient demographics regarding gender, age, mean tumor size and follow-up (FU) time were also extracted from each article.
Data Synthesis Study heterogeneity was quantified through the computation of t², Q, and I² statistics. A Wald-type Q statistic was used to assess statistical significance of study heterogeneity. Assessment of study bias was performed using standard funnel plot analysis and an Egger’s test for funnel plot asymmetry. Significant cross-study heterogeneity was found, with rates of hearing preservation ranging from 0-100% across studies. Aggregate hearing preservation was 32% under a fixed effects model and 35% when allowing for random study effects. When evaluating for study bias, Egger’s test indicated lack of small study effects (P=0.68). As expected, rates of hearing preservation were also strongly dependent on preoperative tumor size, with rates of 48%, 35%, and 12% observed for intracanalicular, small, and large (>20 mm) tumors, respectively.
Conclusions Hearing preservation rates are dependent on multiple factors, and tumor size likely has a strong effect. It is critical to discuss the patient’s expectations for hearing preservation when deciding on treatment plans for VS.