Long‑Term Outcomes of Hearing Preservation After Retrosigmoid Removal of Large Vestibular Schwannoma.

Background: Hearing preservation after large vestibular schwannoma (VS) removal is challenging and the long‑term outcomes of postoperatively preserved hearing have not been elucidated. Objective: We aimed to clarify long‑term outcomes of hearing preservation after the retrosigmoid large VS removal and to recommend a strategy for treating large VS. Materials and Methods: Hearing preservation with total/nearly total (T/NT) tumor removal was accomplished in six of 129 patients who underwent retrosigmoid large VS (≥3 cm) removal. We evaluated the long‑term outcomes of these six patients. Results: Preoperative hearing of these six patients was 15–68 dB by pure tone audiometry (PTA) (Class I: 2, II: 3, and III: 1 by the Gardner‑Robertson (GR) classification). Postoperatively, magnetic resonance imaging (MRI) with gadolinium administration confirmed T/NT removal, the preserved hearing was 36–88 dB (Class II: 4 and III: 2), and no facial palsy occurred. After long‑term follow‑up (8–16 [median: 11.5] years), five patients maintained hearing of 46–75 dB (Class II: 1 and III: 4) while one lost hearing. Three patients showed small tumor recurrence on MRI; two recurrences were controlled by gamma knife (GK) and one showed minimal change only by observation. Conclusions: Hearing preserved after T/NT removal of large VS is maintained for a long time (>10 years), though tumor recurrence on MRI is somewhat common. Detecting small recurrence early, and regular MRI follow‑up contributes to the long‑term maintenance of hearing. Hearing preservation with tumor removal is a challenging yet worthwhile strategy in large VS patients with preoperative hearing. [ABSTRACT FROM AUTHOR]