Impact of Fundal Extension on Hearing After Surgery for Vestibular Schwannomas

Objective: To compare hearing preservation after surgery for intracanalicular vestibular schwannomas with or without fundal extension. Study Design: Retrospective chart review. Patients: Patients with intracanalicular tumors (<= 10-m maximal dimension) undergoing retrosigmoid craniotomy between 2001 and 2010. Intervention: Preoperative and postoperative audiograms, preoperative magnetic resonance imaging, and operative reports were reviewed. Main Outcome Measures: Preoperative and postoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery classification). Results: Complete data for 53 patients (27 female and 24 male subjects, sex was not recorded for 2 patients) meeting selection criteria was available. Fundal involvement was identified in 39 (73.6%) of the 53 patients. The remaining 14 patients did not have tumor with fundal extension (26.4%). Average tumor size for patients with fundal extension (+FE) was 6.9 +/- T 2.2 mm and without fundal extension (-FE) was 8.2 +/- 1.9 mm (p = 0.05, Student's t test). Average preoperative speech discrimination score for the entire study was 90.5 +/- 11.8 (n = 53). After retrosigmoid approach for tumor resection, 79% of patients (42/53) had preserved hearing defined as American Academy of Otolaryngology-Head and Neck Surgery class A, B, or C. Average postoperative speech discrimination score for these patients was 89.3 +/- 12.1, and average postoperative pure-tone average was 35.9 +/- 9.1%. Eighty-five percent (33/39) of +FE patients had preserved hearing (class A, B, or C). In contrast, 64% (9/14) of -FE patients had hearing preserved (class A, B, or C; Fisher's exact test, p = 0.034). Conclusion: Hearing preservation rate after retrosigmoid craniotomy for intracanalicular vestibular schwannomas may be superior for tumors with fundal extension compared with tumors that do not extend to the fundus.