VAGAL NERVE MONITORING DURING PARAPHARYNGEAL SPACE TUMOR REMOVAL

The vagus nerve innervates the intrinsic and extrinsic laryngeal muscu lature as well as the complex pharyngeal plexus. Acute paralysis of th is nerve results in dysfunctional speech, deglutition, and airway prot ection. These untoward effects, which lead to additional infectious an d aerodigestive complications, may arise following manipulation of the vagus nerve during the surgical removal of a variety of neoplasms fou nd in the parapharyngeal space. The vagal nerve has been intraoperativ ely monitored in an effort to maintain its anatomic and functional int egrity. Bipolar hook-wire electrodes are introduced transcutaneously t hrough the cricothyroid membrane and are guided into the vocalis muscl e by an assistant performing direct laryngoscopy. Continuous, real-tim e monitoring of the vagal nerve is provided by audio and visual feedba ck to the operating surgeon. Potentially injurious stretching, heating , and compression of the nerve are easily detected, and monopolar stim ulation of the nerve is used to map the nerve's course through the tum or bed. This presentation outlines our technique for vagal nerve monit oring in patients with tumors of the parapharyngeal space and intact p reoperative vocal cord mobility. Selected cases are presented and illu strated through intraoperative and postoperative videotapes.