What Is the Best Tumor Size to Achieve Optimal Functional Results in Vestibular Schwannoma Surgery?

Objectives: To analyze our own functional results to delineate a critical vestibular schwannoma size for middle cranial fossa (MCF) surgery with the best possible outcome. Study Design: Retrospective chart review. Setting: Academic tertiary referral center. Methods: Tumors were divided into intracanalicular, tumors 1 to 5, 6 to 10, and 11 to 15 mm in the cerebellopontine angle (CPA). Patients were evaluated at 2 months, 1 year, and 5 years after surgery. Results: At 1 year, House-Brackmann score of I or II was obtained in 100% of intracanalicular and in 96%, 86%, and 85% with tumors up to 5, 10, and 15 mm in the CPA, respectively. Class I hearing was postoperatively preserved in 61%, 41%, 29%, and 20%, and measurable word recognition in 67%, 51%, 35%, and 21% of patients, respectively. Conclusion: The outcome is predominantly a function of tumor size, and these changes influence MCF surgery at an earlier stage than in the translabyrinthine or retrosigmoid approach. For the facial nerve, there is a cutoff at 5-mm extracanalicular extension. Also, chances for successful hearing preservation decrease rapidly with size, and in tumors beyond 1.5 cm are below 20%. Consequently, although an expectant policy with small tumors may be reasonable in some instances, it is not so for MCF candidates.