Functional outcome and postoperative complications after the microsurgical removal of large vestibular schwannomas via the retrosigmoid approach: a meta-analysis

For large (≥30 mm) or giant (≥40 mm) vestibular schwannomas (VSs) for which microsurgical removal is the main treatment option, complete tumour resection and the preservation of acceptable facial nerve function can be safely and successfully achieved via the retrosigmoid approach. We performed a meta-analysis to provide a reliable estimate of functional outcome and postoperative complications for patients treated surgically for large VSs. We conducted a comprehensive search in Pubmed, Embase and the Chinese National Knowledge Infrastructure (CNKI) databases to identify publications that included only patients in whom the VSs were >3.0 cm in maximal diameter and microsurgically removed by a retrosigmoid approach. Pooled estimates of proportions with corresponding 95 % confidence intervals were calculated using the Freeman–Tukey double arcsine transformation. This meta-analysis revealed that the pooled proportion of gross total resections was 79.1 % (95 % CI, 64.2–90.8 %; I ² = 95.4 %). By combining microsurgical techniques with continuous electrophysiological monitoring, the anatomical preservation of the facial nerve at the end of surgery was achieved in 88.8 % (95 % CI, 83.6–93.2 %; I ² = 76.1 %) of the patients. The pooled proportion of good postoperative facial nerve function (House–Brackmann (HB) grades I–II) was 62.9 % (95 % CI, 50.0–74.9 %; I ² = 91.1 %). Cerebrospinal fluid leakage was reported in 7.8 % (95 % CI, 4.8–11.4 %; I ² = 49.8 %) of the patients. The mortality rate was 0.87 % (95 % CI, 0.22–1.78 %; I ² = 4.9 %). Our meta-analysis revealed that for large VSs, very favourable results can be obtained using the retrosigmoid approach with minimal mortality, especially with respect to anatomical and functional facial nerve preservation.