Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea Treatment

Abstract

Objective: Reduced upper airway muscle activity during sleep contributes to obstructive sleep apnea (OSA) pathogenesis. A novel therapy (HGNS, Apnex Medical, Inc) is designed to address this issue by stimulating the hypoglossal nerve synchronous with respiration during sleep. This study evaluated the safety and effectiveness of HGNS for OSA treatment. Method: From 2009-2010, 32 subjects with moderate to severe OSA underwent implantation of the HGNS system. Subjects had objective assessment using laboratory polysomnography (PSG) and subjective symptom assessment using validated questionnaires. Preliminary analyses are presented. The primary outcome variable was the change in apnea hypopnea index (AHI). Results: HGNS was used on a median of 97% of nights, with a mean use of 5.1 ± 1.7 hours per night. Thirty-one/32 subjects had PSGs at the 3- and/or 6-month interim time points. Treatment with HGNS therapy resulted insignificant improvement in AHI (45.4 ± 17.5 to 23.2 ± 18.50; P < .05). Symptoms also improved (all P < .05): Epworth Sleepiness Scale (12.0 ± 4.6 to 8.3 ± 3.9), Functional Outcomes of Sleep Questionnaire (14.2 ± 2.0 to 16.6 ± 2.3), and Pittsburgh Sleep Quality Index (10.5 ± 3.0 to 8.4 ± 4.1). There was no change in body mass index. Conclusion: HGNS therapy was associated with a significant decrease in AHI and improvement in symptoms, and compliance was high. Based on the results of this feasibility trial, the HGNS System will be evaluated in a randomized pivotal trial.