Determining benchmarks in hearing preservation surgery for vestibular schwannoma

Abstract

Objectives: The objectives of this study were to determine minimal benchmarks of success in vestibular schwannoma hearing preservation surgery, wherein the likelihood of having preserved hearing in a single patient is at least as likely as having created a poor facial nerve outcome for a single patient. Design: This is a statistical analysis of published literature. Setting: Academic Tertiary Medical Center. Main Outcome Measures: Based on published natural history data, the number needed to treat (NNT) equation was used to calculate the minimally acceptable hearing preservation rates within various hearing classi fication schemes. Results: Given good facial nerve outcome rates of 85, 90, and 95%, the corresponding hearing preservation rates at 4.7 years that are likely to preserve classes A and B hearing (American Academy of Otolaryngology-Head and Neck Surgery classi fication) in a single patient as to cause a poor facial nerve outcome are 70, 65, and 60%, respectively. If surgery is limited exclusively to intracanalicular tumors, these rates drop to 62, 57, and 52%, respectively. If the word recognition scoring classification is used, required hearing preservation rates are higher. Conclusion: It is possible to use the NNT equation alongside projected facial nerve outcomes to estimate benchmarks of minimally acceptable hearing preservation rates. Copyright © 2012 by Thieme Medical Publishers, Inc.