The Association of Upper Airway Anatomy and Hypoglossal Nerve Stimulation Response in OSA

Hypoglossal nerve stimulation (HGNS) is a promising surgical treatment of obstructive sleep apnea (OSA) for patients intolerant to positive airway pressure (PAP). Nonetheless, more than one-third of patients have suboptimal outcomes, demonstrating the need for improved understanding of factors associated with treatment effectiveness. This study examined the relationship between anatomy measures from computed tomography (CT) and HGNS outcomes.

A prospective cohort study of consecutively enrolled adults with moderate or severe OSA (AHI > 15 events/h) who underwent HGNS implantation between February 2020 and June 2024. Preoperative CT scans were obtained following a standardized protocol. Anatomic traits, including the size of the tongue and the surrounding craniofacial structures, were quantified. HGNS response was defined by the Sher criteria (≥ 50% reduction in apnea-hypopnea index [AHI] and postoperative AHI < 20 events/h).

A total of 65 patients were included: 31 HGNS responders and 34 nonresponders. On average, patients were 63.3 ± 11.7 years old, overweight (BMI of 29.5 ± 4.0 kg/m²), about half were male (50.8%) and most were White (89.2%); the average AHI was 28.6 ± 13.3 events/h. No statistically significant associations with HGNS response were observed for relative tongue volume (tongue volume/total oral cavity volume; OR: 0.82 [0.48-1.40]; p = 0.46), absolute tongue volume (OR: 1.27 [0.62-2.61]; p = 0.52), or total oral cavity volume (OR: 1.81 [0.82, 3.99]; p = 0.14). Exploratory analysis showed hyoid position and transverse maxillary dimensions were associated with response status.

Our study did not find a significant association between relative tongue volume and HGNS response. Further investigations in larger samples may elucidate links between HGNS response and upper airway anatomy.