Monitoring of the hypoglossal nerve during general anesthesia

Abstract

Injury to a cranial nerve during carotid surgery is a common complication, with an incidence of more than 10%. 1,2 In redo procedures or in irradiated necks, the incidence is estimated to be as frequent as 20%. 3 The hypoglossal nerve is affected in more than half of these patients.Recently the use a nerve stimulator was described in the Journal of Vascular Surgery. 4 This nerve stimulator allowed identification and preservation of the hypoglossal nerve in a case of carotid surgery in a scarred neck, but its use was restricted to an awake, cooperating patient.We recently used a commercially available neuromonitoring system (NeuroSign 100; Inomed, Teiningen, Germany)-widely used in thyroid surgery 5 -to monitor the hypoglossal nerve with the patient under general anesthesia. A very thin detection needle is placed in the ipsilateral half of the tongue; the earthening electrode is placed in the sternocleidoid muscle. A stimulator is then used to either identify the location of the nerve or to document its function, which is proven through an acoustic and an optic signal.This easy method to identify the hypoglossal nerve and to document its function may help to prevent the nerve's injury in locally complex situations. In contrast to the technique described previously, 4 it may also be performed with the patient under general anesthesia.

Hypoglossal Nerve Palsy After Airway Management for General Anesthesia

“…Bohner et al described the first use of a nerve stimulator for the successful identification and continuous monitoring of the hypoglossal nerve during an anatomically challenging carotid endarterectomy under general anesthesia. 81 …”