Early Experience with Hypoglossal Nerve Stimulation in Japanese Patients: Trends in Operative Time and Treatment Outcomes

OBJECTIVE:Hypoglossal nerve stimulation (HNS) has emerged as an effective treatment for obstructive sleep apnea (OSA) in patients who cannot tolerate continuous positive airway pressure. However, data on Asian populations, particularly Japanese patients, are limited. This study evaluated the operative time and clinical outcomes of HNS therapy in a Japanese cohort. METHODS:This study included 18 patients with moderate-to-severe OSA who underwent HNS implantation (Inspire UAS system®) at the study hospital between August 2022 and December 2024. Operative time, intraoperative blood loss, and perioperative complications were recorded to assess surgical efficiency. Sleep parameters, including apnea-hypopnea index (AHI), 3 % oxygen desaturation index (ODI), minimum SpO₂, time with SpO₂ < 90 %, Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and patient-reported impressions, were evaluated at 6 and 12 months post-implantation. RESULTS:The average operative time was 118.4 ± 48.6 min. Analysis of the surgical learning curve showed a significant decrease in operative time with increasing case number (ρ = -0.876, p < 0.01). Nonlinear regression using a logarithmic model indicated that operative time tended to decrease progressively with increasing surgical experience, with greater reductions observed in the early cases and more gradual decreases in later cases. Adverse events were infrequent, with one patient requiring device explantation. At 6 months, the mean AHI decreased from 30.8 events/hour (/h) to 9.5/h (p < 0.001), ODI from 25.9 /h to 7.2 /h (p < 0.001), ESS from 11.3 ± 6.0-7.3 ± 4.0 (p = 0.006), and PSQI from 11.4 ± 3.6-7.3 ± 3.1 (p = 0.008). These improvements were sustained at 12 months, with high patient satisfaction reported in ≥ 90 % of cases. CONCLUSION:HNS implantation is safe, and operative time decreases progressively with increasing experience. HNS therapy is effective and feasible for Japanese patients with OSA and produces substantial improvements in both objective sleep parameters and patient-reported outcomes. Despite the small sample size and short follow-up period, this pilot study provides important initial evidence supporting the applicability of HNS in Asian populations.