(1328) Hypoglossal Nerve Stimulation: Correlation Between Intraoperative Extinguishing Thresholds and Postoperative Therapeutic Amplitudes

Introduction: Hypoglossal nerve stimulation (HGNS) is an effective surgical therapy for obstructive sleep apnea, yet postoperative programming requirements vary. Intraoperative extinguishing thresholds are routinely recorded during implantation, but their relationship to postoperative therapeutic amplitudes and treatment success remains unclear. Clarifying this association may inform early programming and patient counseling.

Methods: A retrospective review of adults undergoing HGNS implantation by a single surgeon (December 2021–May 2025) was conducted. Inclusion required completed implantation, device activation, and available postoperative apnea–hypopnea index (AHI) data. The primary exposure was intraoperative extinguishing threshold. Outcomes included postoperative amplitudes, AHI reduction, and HGNS treatment success (>50% AHI reduction and final AHI < 20 events/hour). Pearson correlation and multivariable regression analyses were performed.

Results: Of 181 patients, 143 had postoperative AHI outcomes, with an overall success rate of 80.4%. Starting postoperative amplitude correlated with intraoperative extinguishing threshold (r = 0.211, p = 0.005) and was higher in females (1.82 vs 1.41 mA, p < 0.001). In multivariable analysis, intraoperative threshold (B = 0.356, p = 0.020) and female sex (B = 0.384, p = 0.001) predicted starting amplitude (R² = 0.108). Most recent amplitude showed a weaker correlation with intraoperative threshold (r = 0.152, p = 0.044) and remained higher in females (2.07 vs 1.74 mA, p = 0.005); only sex remained significant. No amplitude measures were associated with AHI reduction or HGNS success.

Conclusions: Intraoperative extinguishing thresholds predict early postoperative HGNS amplitudes but do not predict long-term programming needs or treatment success. Female patients required higher stimulation amplitudes independent of intraoperative thresholds. While intraoperative measurements may aid initial programming, they should not be used to predict HGNS outcomes. Prospective study is needed to clarify physiologic contributors to programming variability.