A meta-analysis of surgical treatment for vestibular schwannoma: is hospital volume related to preservation of facial function?

To investigate the relation between hospital volume and preservation ratios of facial function in surgery for vestibular schwannoma. A meta-analysis was conducted on current literature concerning preservation ratios of facial function after surgical resection of vestibular schwannoma. Studies reported by the House-Brackmann grading system for facial function were searched; all studies were published in English in peer-reviewed journals between 1992 and 2007. Articles had to report 1) patients who had surgery for vestibular schwannoma, 2) House-Brackmann grades for facial function, and 3) calendar time and number of procedures. Standard methods for meta-analysis were adapted. Data were pooled by weighing studies according to their accuracy. Results were sorted for low-, moderate-, and high-volume hospitals. Linear relations were quantified by metaregression analysis (n = 5,560). Findings of this meta-analysis suggest that there is a linear relation between hospital volume and preservation ratio of facial function. The concentration of surgical treatment might be a consideration to optimize clinical outcome. Prospective and nationwide registration of surgical results might contribute to more definitive conclusions regarding outcome of vestibular schwannoma surgery