1313 Marked Reduction in Apnea–Hypopnea Index After Hypoglossal Nerve Stimulation in Severe Obstructive Sleep Apnea: A Case Report

Abstract Introduction Hypoglossal nerve stimulation (HNS) is an alternative treatment for obstructive sleep apnea (OSA) in patients who are unable to tolerate continuous positive airway pressure (CPAP). This case describes a patient with extremely severe OSA and a BMI slightly above typical eligibility cutoffs who experienced substantial improvement after HNS therapy. Report of case(s) A 51-year-old man (BMI 35 kg/m²) was evaluated for long-standing loud snoring and marked daytime sleepiness. Home sleep apnea testing on 11/16/2022 showed very severe OSA with an apnea–hypopnea index (AHI) of 92.3 events/hour, oxygen saturation nadir of 74%, and 27.2% of total sleep time below 89% saturation. Several trials of auto-adjusting positive airway pressure (APAP) were unsuccessful because of pressure intolerance and mask discomfort. Drug-induced sleep endoscopy on 5/17/2024 revealed partial anteroposterior tongue-base collapse without concentric palatal collapse, supporting candidacy for HNS. The patient underwent HNS implantation on 11/12/2024, with device activation on 12/30/2024. Titration polysomnography on 7/22/2025 demonstrated a reduction in AHI to 6.9 events/hour at a stimulation amplitude of 2.6 V. The oxygen saturation nadir improved to 89%, with only 0.1% of sleep time below 89%. Sleep efficiency was 74.6%, REM sleep accounted for 8.7% of total sleep time, and the periodic limb movement index was 0. Mean nightly HNS use was 6 hours 56 minutes, with 100% adherence (>4 hours/night). The Epworth Sleepiness Scale score improved from 18 to 4, and both snoring and daytime sleepiness resolved. BMI remained stable (35→34 kg/m²). No perioperative complications occurred, and improvements persisted at 10-month follow-up. Conclusion This case highlights the sustained benefit of HNS in a patient with extreme OSA severity and a BMI above 34 kg/m². Careful DISE-guided selection and consistent device use resulted in marked physiologic and symptomatic improvement. This experience supports the real-world effectiveness of HNS for selected patients who fall slightly outside traditional BMI cutoffs. Support (if any) None.