Electrical Stimulation of the Genioglossus in Patients with Residual Obstructive Sleep Apnea Post-UPPP Surgery

Abstract

Objective: Genioglossus is a major upper-airway dilator muscle, which leads to upper-airway obstruction when its activity is decreased. We evaluated the effect and safety of genioglossus stimulation for patients with residual mild-to-moderate obstructive sleep apnea (OSA) after uvulopalatopharyngoplasty (UPPP). Methods:We enrolled 23 patients diagnosed with OSA by polysomnography (PSG) 6 months after UPPP, who underwent nightly transcutaneous genioglossus stimulation (TGS) therapy. Apnea hypopnea index (AHI), microarousal index (MAI), the ratio of duration of SpO2 < 90% to total sleep time (T90) and Epworth sleepiness scale (ESS) before and during TGS treatment were compared. We first observed the overall effect of TGS, and then compared its influence on patients with mild and moderate sleep apnea.Results: Compared with non-TGS therapy, there was a significant decrease in AHI, MAI, T90, and ESS (9.15 ± 4.21 vs. 17.90 ± 6.85, p < 0.0001; 6.33 ± 3.75 vs. 10.93 ± 4.90, p < 0.0001; 4.87 ± 4.02 vs. 9.13 ± 4.24, p < 0.0001; 8.65 ± 3.35 vs. 9.30 ± 3.10, p = 0.002, respectively), and a significant increase in mean SpO2 and minimal SpO2 (mini SpO2) (95.52% ± 0.95% vs. 94.43% ± 1.12%, p < 0.0001; 88.74% ± 2.94% vs. 85.17% ± 4.67%, p < 0.0001, respectively) during TGS treatment. Patients in the mild and moderate groups had the same variation trend between TGS and non-TGS therapy nights. However, the moderate group had a higher absolute value of changed AHI (AHI; 11.12 ± 3.95 vs. 5.66 ± 1.70, p < 0.05) and MAI (MAI; 5.8 (3.3, 8.6) vs. 2.5 (1.05, 5.6), p < 0.05) than the mild group. There were no significant differences in absolute changed mean SpO2 (mean SpO2), absolute changed miniSpO2 (miniSpO2), changed T90 (T90) and absolute changed ESS (ESS) between the two groups. Moreover, the percentage of AHI was not different between the two groups (47.89% ± 13.79% vs. 51.04% ± 13.32%, p = 0.587). There was no perceived discomfort during TGS therapy and no procedure-related adverse events. Conclusion:Submental transcutaneous electrical stimulation of the genioglossus led to a significant reduction in AHI and improvement of daytime sleepiness for existing mild-to-moderate OSA patient's post-UPPP surgery.