Left- vs Right-Sided Upper Airway Stimulation

Introduction: Upper airway stimulation (UAS) is a treatment option for obstructive sleep apnea (OSA) in which electrical stimulation is applied to the hypoglossal nerve. Nerve branches that control tongue protrusion are located inferiorly. Due to positioning, left sided implants are typically placed with an inferiorly oriented electrode cuff (L-down) as opposed to superiorly on the right (R-up). In this study, we assess the impact of left versus right sided UAS on patient outcomes.

Methods: Patients who underwent UAS implantation between 2016 and 2021 with a L-down or R-up oriented cuff as confirmed by X-ray were included. Data were collected retrospectively. Most recent sleep study variables were used for analysis.

Results: 190 patients met inclusion criteria. The average age was 61.0±11.0 years, with 55 (28.9%) females. L-down orientation was present in 21 (11.1%) patients vs. 169 (88.9%) R-up. Indications for L-down included hunting/shooting (n=15), prior radiation/surgery (n=4), central port (n=1), and brachial plexus injury (n=1). Adherence was higher among L-down patients (47.1 vs. 41.0 hours use/week, p=0.037) with similar time to adherence data collection (4.4 vs. 4.2 months, p=0.612). Proportion of postoperative polysomnogram as opposed to home sleep study was similar between cohorts (73.7% vs. 66.7%, p=0.724). Decrease in apnea hypopnea index (21.3 vs. 22.8, p=0.734), treatment success (76.5% vs. 84.0%, p=0.665), functional threshold (1.5 vs. 1.6, p=0.550), therapeutic amplitude (2.3 vs. 2.4, p=0.882), and decrease in Epworth Sleepiness Scale (4.9 vs. 2.6, p=0.060), were not significantly different between cohorts.

Conclusions: Left sided UAS is associated with increased adherence with similar clinical outcomes, which may indicate improved patient comfort or perceived efficacy. Further investigation is warranted.