Lateral wall collapse from sleep endoscopy and airflow shape predicts hypoglossal nerve stimulation efficacy in obstructive sleep apnea.

Rationale: Patient selection for hypoglossal nerve stimulation (HGNS) for obstructive sleep apnea (OSA) requires assessment of pharyngeal site of collapse using drug-induced sleep endoscopy (DISE).

Objectives: The current study aims to address two key knowledge gaps: First, we prospectively confirm that, among HGNS candidates, reduced HGNS efficacy is associated with oropharyngeal lateral wall (OLW) collapse (Aim 1). Second, given DISE is resource-intensive procedure and delays treatment, we evaluate whether a recently-developed non-invasive method for identifying OLW collapse using airflow shapes is associated with reduced HGNS efficacy (Aim 2).

Methods: Patients who underwent DISE, HGNS implantation, and follow-up sleep testing were included in Aim 1 (n=369) as part of an observational cohort study. For Aim 2, airflow data estimating OLW collapse probability were collected during DISE pneumotachograph (n=138, DISE Flow cohort); and from a home sleep test nasal cannula for validation (n=46, HST cohort). Linear regression quantified associations between HGNS efficacy (%reduction in AHI) and DISE-determined OLW collapse (Aim 1) or flow-shape-determined OLW collapse (probability score per 2SD; Aim 2), adjusting for baseline AHI.

Results: Compared to non-OLW collapse, DISE-determined OLW collapse reduced HGNS efficacy [95%CI] by ‒18.0[‒31.9,‒6.2]%. Increased flow-shape-determined OLW collapse probability (Δ2SD) was associated with reduced HGNS efficacy in both DISE Flow (‒24.8 [‒40.4, ‒11.7]%) and HST (‒22.7 [‒50.0, ‒2.6]%) cohorts.

Conclusion: This study prospectively validates OLW collapse as a key factor in HGNS failure and shows that airflow-based identification of OLW collapse can effectively estimate HGNS efficacy, representing a significant advancement in patient selection for HGNS.