Intraoperative vagal nerve monitoring

A variety of benign and malignant neoplasms occur in the superior cervical neck, parapharyngeal space or the infratemporal fossa. The surgical resection of these lesions may result in postoperative iatrogenic injury to the vagus nerve with associated dysfunctional swallowing and airway protection. Anatomic and functional preservation of this critical cranial nerve will contribute to a favorable surgical outcome. Fourteen patients with tumors of the cervical neck or adjacent skull base underwent intraoperative vagal nerve monitoring in an attempt to preserve neural integrity following tumor removal. Of the 11 patients with anatomically preserved vagal nerves in this group, seven patients had normal vocal cord mobility following surgery and all 11 patients demonstrated normal vocal cord movement by six months. In an earlier series of 23 patients with tumors in the same region who underwent tumor resection without vagal nerve monitoring, 18 patients had anatomically preserved vagal nerves. Within this group, five patients had normal vocal cord movement at one month and 13 patients demonstrated normal vocal cord movement at six months. This paper will outline a technique for intraoperative vagal nerve monitoring utilizing transcricothyroid membrane placement of bipolar hook-wire electrodes in the vocalis muscle. Our results with the surgical treatment of cervical neck and lateral skull base tumors for patients with unmonitored and monitored vagal nerves will be outlined.