0647 The Promise and Pitfalls of Hypoglossal Nerve Stimulation (HNS) in Obstructive Sleep Apnea

Abstract Introduction Obstructive sleep apnea(OSA) is a prevalent disorder associated with cardiometabolic and neurocognitive morbidity. While CPAP remains gold-standard therapy, many patients are intolerant to it. HNS has emerged as an alternative for patients with moderate-to-severe OSA and BMI 40kg/m2 ,but adherence and response are variable. This study assesses long-term outcomes, compliance, and symptom improvement among patients using HNS and identifies subgroups more likely to struggle with therapy. Methods We conducted a retrospective data-analysis of patients implanted with Inspire HNS and followed at Corewell Health Beaumont University Sleep Clinic from January2021-December2024. All patients underwent preoperative drug-induced sleep endoscopy and baseline polysomnography or home sleep apnea testing. Outcomes included apnea-hypopnea index(AHI) reduction, device compliance(4hours per night on 70% of nights), and Epworth Sleepiness Scale(ESS) improvement(10 at baseline to 10 on follow-up). Patient-reported adverse effects and co-morbid sleep disorders like insomnia and insufficient sleep were also recorded. Results 52patients were implanted with HNS during the study period. Seven were excluded due to lack of follow-up after activation. Of the included 45, ten patients did not complete titration studies and three had no post-titration follow-up. One patient discontinued use due to intolerance and three transitioned to alternate therapies. The mean age was 64.5years(range 42–83), mean BMI 30.3kg/m2, and 35.6% were female. Mean and median AHI were 31.8 and 24.7, respectively, improving to 8.7 and 1.4 at final titration amplitude. 26 patients(57.8%) met compliance thresholds, with mean nightly use of 6.7hours; but only 15 maintained the therapeutic amplitude identified during titration. ESS improvement was limited, with 5 patients meeting the criteria. Adverse effects included nocturnal awakenings, jaw pain, neuropraxia, and intolerance to higher amplitudes. Pre-existing sleep disorders strongly influenced outcomes: of 16 patients(35.6%) with insomnia, half demonstrated poor compliance; among 10 patients(22.2%) with insufficient sleep syndrome, 70% were non-adherent. Conclusion HNS is an effective alternative for CPAP-intolerant OSA patients; however, compliance and symptom improvement remain inconsistent. Adverse effects and difficulty maintaining therapeutic amplitude limited outcomes. Pre-existing insomnia or insufficient sleep strongly predicted non-adherence, highlighting importance of individualized patient selection and targeted screening. Future research comparing CPAP and HNS adherence and assessing long-term cardiovascular and quality-of-life outcomes are warranted. Support (if any)