Can You Hear Me Now? Long-Term Hearing Preservation in Intracanalicular Vestibular Schwannoma

Abstract

Introduction: The primary goal of treating intracanalicular vestibular schwannomas (IVS) is often hearing preservation. There are three viable approaches to this goal: watchful waiting, stereotactic radiosurgery, and microsurgical resection. We have favored microsurgical excision via the middle fossa route when hearing preservation is the patient's primary goal, but we have also utilized stereotactic radiosurgery and watchful waiting in appropriate circumstances. We review our experience in achieving the goal of hearing preservation in patients with intracanalicular vestibular schwannoma in whom a minimum of 8 years' follow-up is available. Methods: Consecutive patients evaluated with intracanalicular vestibular schwannoma at our institution were identified from clinic and hospital records and a prospectively managed data base. Pre- and serial postoperative audiometry, clinical evaluation of facial nerve function, and post-treatment complications were extracted from medical records. Serial postoperative contrast enhanced MRI were reviewed for evidence of tumor recurrence. Results: Data collection is ongoing and will be updated for the meeting. Between 1987 and 1997 we performed 36 middle fossa operations for vestibular schwannoma. Hearing preservation was attempted in 35 who had Gardner-Robertson class I or II hearing preoperatively, one of whom is lost to follow-up. Of the 34 patients, serviceable hearing was preserved in 20 (59%). In those with preserved hearing the median word recognition score is 96% and median pure tone average 33 dB. At 36 months of follow-up these values are statistically unchanged, suggesting that hearing, once preserved, is well maintained. Conclusion: When hearing is preserved after microsurgical excision of IVS it appears to be well maintained. Hearing progressively declines in untreated and radiosurgically treated patients followed up to 3 years after treatment or diagnosis. Longer follow-up of surgically treated patients, which will be presented at the meeting, will clarify the relative value of these approaches.