Intraoperative monitoring of the vagus nerve during intracranial glossopharyngeal and upper vagal rhizotomy: technical note.

Intracranial section of the glossopharyngeal and upper vagal rootlets for the treatment of vagoglossopharyngeal neuralgia may cause dysphagia or vocal cord paralysis from injury to the motor vagal rootlets in 10% to 20% of cases. To minimize this complication, we recently applied a technique of intraoperative monitoring of the vagus nerve (previously described by Lipton and McCaffery to monitor the recurrent laryngeal nerve during thyroid surgery) in a patient undergoing intracranial rhizotomy for vagoglossopharyngeal neuralgia. By inserting an electrode in the ipsilateral false vocal cord and stimulating the rostral vagal rootlets intraoperatively under general anesthesia, we could differentiate the rostral vagal motor rootlets from the sensory rootlets. In this patient, the technique allowed us to preserve a rostral vagal rootlet, which if sectioned, could have caused dysphagia or vocal cord paralysis. We conclude that intraoperative monitoring of the rostral vagal rootlets is an important technique to minimize complications of upper vagal rhizotomy.