[Electrophysiologic monitoring of the facial nerve during otoneurosurgery].

The use of intraoperative facial electromyography (EMG) during otoneurosurgery facilitates anatomic and functional preservation of the VII nerve recording neural activation evoked both mechanically and electrically. The present work presents a personal experience involving the use of this technique in 27 cases of otoneurosurgery (16 neuromas of the acoustic nerve, 4 tympano-jugular paragangliomas, 5 VII nerve decompressions, 1 vestibular neurectomy, and 1 VII nerve neuroma monitored intraoperatively with Nicolet Nerve Integrity Monitor-1 (NIM-2). The latter is a highly sensitive instrument for intraoperative electromyographic recording. It is equipped with a system for electric stimulation, a display and a speaker for the EMG signal and acoustic alarm. During monitoring basically 3 types of EMG responses can be recorded: "burst", "train" and "pulse". In the present work the various EMG patterns are analyzed in detail as well as the relationship between their emergence and the type of surgical procedure performed. Intraoperative interpretation of the EMG activity makes possible more precise, intricate surgical maneuvers. It is felt that intraoperative monitoring has made it possible to preserve the anatomy and functionality of the facial nerve more frequently than is possible with other unmonitored cases. This becomes most evident when evaluating the long-term results.