Pharyngeal patency caused by stimulation of the hypoglossal nerve in anaesthesia-relaxed patients.

Impaired function of the genioglossal muscle is the most frequent reason for upper airway obstruction during sleep. Functional electrical stimulation (FES) of the hypoglossal nerve may be used to push the tongue forward to release the obstruction. Anaesthesia-induced upper airway obstruction resembles the situation during obstructive sleep apnea (OSA) syndrome. In order to develop an implantable FES system for treatment of OSA, we stimulated the exposed hypoglossal nerve in 6 patients undergoing radical cancer surgery of the head and neck region. Tongue movements during stimulation were video filmed and the amount of unobstructed airway achieved with stimulation was estimated using the adjacent intubation tube as reference. In every case, stimulation created an unobstructed airway, larger than the intubation tube.