[Intraoperative monitoring of the lower cranial nerves during skull base surgery: evoked electromyographic technique].

Functional preservation of the lower cranial nerves is an important issue in the surgery of the skull base to avoid postoperative serious complications such as aspiration pneumonia and respiratory disorders. We presented our experience of intraoperative monitoring of the lower cranial nerves during skull base surgery. The evoked electromyographic (EMG) activities were successfully recorded from the muscles innervated by the lower cranial nerves. These EMG recordings are helpful to guide the surgeon intraoperatively and to avoid careless severing of these nerves. Although the glossopharyngeal nerve that innervates only one small muscle in the pharynx (M. stylopharyngeus) cannot be monitored with the evoked EMG technique described in this paper, the position of this nerve can be deduced from the position of the vagus nerve.