Comparison of balance outcomes according to treatment modality of vestibular schwannoma.

OBJECTIVES: We sought to compare balance outcomes according to treatment modality of vestibular schwannoma (VS) via a meta-analysis that divided measuring tools of balance outcomes into three categories based on type. METHODS: A comprehensive review of the literature from January 1966 to September 2017 was performed, looking for studies about long-term balance outcomes after microsurgery (MS), radiotherapy (RT), or observation for VS. A comprehensive meta-analysis was used to analyze effect sizes, explore possible causes of heterogeneity, and check publication bias with a funnel plot and Egger's regression. RESULTS: Among 633 references, 34 were included in the meta-analysis. Perceived dizziness improvement rate was significantly higher in the MS group than in the RT group (odds ratio [OR]: 1.61; 95% confidence interval [CI]: 1.08 to 2.40; P < .05, I2 = 4.18], but no significant difference was observed between the two groups with regard to validated dizziness questionnaire score (standardized mean difference: 0.04; 95% CI: -0.36 to 0.44; P = .84, I2 = 69.61) or dizziness or disequilibrium-related symptom incidence rate (OR: 0.91; 95% CI: 0.50 to 1.68; P = .77, I2 = 0). In a subanalysis conducted within the groups after intervention, the MS group demonstrated a lower vertigo incidence rate (P < .001), and the RT group experienced a significant reduction in validated dizziness questionnaire score (P < .05). CONCLUSIONS: Our results indicate that MS should be considered at least equal to RT in regard to resolving long-term dizziness and improving balance outcomes. Furthermore, well-designed studies are necessary to predict balance outcomes after VS treatment and to choose from among possible treatment options. LEVEL OF EVIDENCE: 2a Laryngoscope, 130:178-189, 2020.