Surgical Management of Internal Auditory Canal and Cerebellopontine Angle Facial Nerve Schwannoma

Abstract

OBJECTIVE: To investigate the long-term patient outcomes after tumor debulking for internal auditory canal facial schwannoma (FNS). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Patients operated on between 1998 and 2010 for a preoperative diagnosis of vestibular schwannoma with the intraoperative identification FNS instead. INTERVENTION: Diagnostic and therapeutic. MAIN OUTCOME MEASURES: House-Brackmann facial nerve score immediately and at long-term follow-up (>1 yr); recurrence of tumor. RESULTS: Sixteen patients were identified who were presumed to have vestibular schwannoma but intraoperatively were diagnosed with facial nerve schwannoma. Eleven underwent debulking surgery (67%-99% tumor removal), 2 underwent decompression only, 2 were diagnosed with nervus intermedius tumors and had total tumor removal with preservation of the motor branch of cranial nerve VII, and 1 had complete tumor removal with facial nerve grafting. Five of 11 debulking patients underwent the middle cranial fossa approach for tumor removal; the remainder had translabyrinthine resections. One debulking patient was lost to follow-up. Nine of 10 patients with long-term follow-up had House-Brackmann Grade I or II facial function. One patient had recurrence of the tumor that required revision surgery with total removal and facial nerve grafting. CONCLUSION: Tumor debulking for FNS provides an opportunity for tumor removal and excellent facial nerve function. Continuous facial nerve monitoring is vital for successful debulking surgery. FNS debulking is feasible via the middle cranial fossa approach. Serial postoperative imaging is warranted to monitor for recurrence.