Patterns and Predictors of Hearing Loss in Observed Vestibular Schwannoma

Abstract

Objective: Reliable long-term hearing preservation with vestibular schwannoma remains elusive. The majority of patients will ultimately lose serviceable hearing in the tumor ear as a result of disease or treatment. The primary objective of this study is to characterize long-term hearing loss in a large cohort of conservatively managed vestibular schwannoma patients and to identify predictors of audiometric decline. Patients and Methods: Retrospective review of 89 adult patients from two independent centers who were managed with observation, receiving serial MRI, and audiograms. Only patients with serviceable hearing at the time of diagnosis were included. Patients with neurofibromatosis type 2 and those who have received prior treatment were excluded. Tumor size and hearing capacity were classified according to the 1995 American Academy of Otolaryngology–Head and Neck Surgery reporting guidelines. Results: A total of 89 patients were included in the analysis. The mean age at the time of diagnosis was 56 years, 60% were females, and the average duration of audiometric follow-up was 64 months (range, 11–126 months). Overall, 64% of tumors were purely intracanalicular and 55% were leftsided. Overall, 16% of tumors demonstrated radiologic growth during the period of study. At time of diagnosis, 41 (50%) had class A hearing and 41 (50%) had class B hearing. At the last follow-up, 62% of patients remained within the same hearing class. Overall, at a mean of 64 months, 62% maintained serviceable hearing, whereas31% progressed to class C (8%) or class D (23%) hearing. Patients who started with class A hearing were significantly more likely to retain serviceable hearing at last follow-up, compared with those with class B hearing at diagnosis (85 vs. 46%; p < 0.001). Conclusion: At a mean of 64 months following diagnosis, 62% of observed VS patients with baseline serviceable hearing will maintain class A or class B capacity. Class B hearing at diagnosis and longer duration of audiometric follow-up were the primary predictors of nonserviceable hearing.