Facial nerve monitoring during acoustic neuroma removal.

As the surgeon's ability to perform total acoustic tumor removal without major neurologic deficit has reached a pinnacle, preservation of facial nerve function has assumed a higher priority. Satisfactory postoperative facial function depends upon an anatomically and physiologically intact facial nerve. Precise localization of the facial nerve is the first step toward preservation of function. Intraoperative facial nerve (FN) stimulation allows the surgeon to safely locate the facial nerve. Monitoring evoked electromyographic activity with an audio speaker provides direct, ongoing information regarding trauma to the nerve during dissection. Intraoperative FN monitoring was used in 18 consecutive translabyrinthine acoustic tumor removals. Seventeen patients had an excellent facial nerve result (Grade I or II using the House 6-point scale). The authors conclude that intraoperative FN stimulation and monitoring during acoustic tumor removal is a safe and reliable method of locating and protecting the facial nerve during cerebellopontine angle surgery.