[Intraoperative facial nerve monitoring in parotid surgery]

Neurophysiological monitoring of cranial motor nerves has proved to be of value in cerebellopontine and skull base surgery. Unfortunately, facial nerve monitoring has been used infrequently for routine parotid gland surgery because suspicion of expense, possible unreliability and the requirement for extra personnel. This study presents clinical experience at the University of Erlangen with facial nerve monitoring during parotid gland surgery done by residents. Advantages are also emphasized for the experienced ENT-surgeon for use during revision parotidectomy. In 35 consecutive patients with benign parotid gland tumors intraoperative monitoring of the facial nerve was done using two different two-channel electromyography units. Bipolar coaxial electrical stimulation was superior to the monopolar stimulation mode. The average operative time and postoperative functional results were compared with those of a control group consisting of 24 patients without monitoring. Findings demonstrated a reduction is operative time and better functional outcome in the patient group with monitoring. Additionally four patients had to undergo total revision parotidectomy because of recurrent benign tumors, while one patient suffered from chronic parotitis due to sialolithiasis and required complete parotidectomy for relief of symptoms. No patient developed permanent facial paresis and nerve monitoring proved to be very helpful for identification and protection of the facial nerve in scar tissue.