The Effect of Neuromuscular Stimulation of the Genioglossus on the Hypopharyngeal Airway

OBJECTIVES: To determine the effects of neuromuscular stimulation (NS) of the genioglossus muscle on hypopharyngeal airway size. STUDY DESIGN: Fourteen consecutively recruited healthy volunteers underwent percutaneous electrical NS of the genioglossus muscle. METHODS: Bipolar hooked wires were inserted percutaneously into the genioglossus muscle and used for NS. The anterior--posterior diameter of the hypopharynx was measured at the level of the superior edge of the epiglottis at baseline and during NS from recorded video endoscopic examinations. RESULTS: NS of the genioglossus muscle resulted in a significant increase in the diameter of the hypopharyngeal airway (P =.002) compared with baseline, ranging from a 33% to 284% increase in airway diameter. Three of the 14 patients demonstrated modest decreases in airway diameter, likely the result of faulty electrode placement in surrounding tongue retrusive muscles. CONCLUSIONS: NS of the genioglossus muscle was effective in increasing the hypopharyngeal airway and may provide a useful alternative to direct stimulation of the hypoglossal nerve with a nerve cuff electrode in the development of neuroprosthetic treatments for obstructive sleep apnea.