Effect of Malocclusion on Response to Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea

Variations in craniofacial anatomy have been associated with the development of obstructive sleep apnea (OSA) and may impact the response to medical and surgical therapies. This study aims to evaluate the effect of malocclusion on the clinical response to hypoglossal nerve stimulator (HNS) therapy.

This is a retrospective cohort study evaluating patients with OSA who underwent HNS placement between May 2017 and December 2022. Occlusion was determined using Angle's Classification Criteria, and outcome measures including preoperative and postoperative Apnea-Hypopnea Index (AHI), lowest O2 saturation (SpO2), and Epworth Sleepiness Scale (ESS) scores were analyzed. Two cohorts were created by grouping patients with normal occlusion and those with class II or class III malocclusion.

Of the 64 patients included in the study, 49 had normal occlusion and 15 had malocclusion. There was no significant difference in age, BMI, or pre-operative AHI between groups. The median AHI in those with normal occlusion was significantly reduced with HNS therapy, going from 35.9 to 8.2 (p < 0.0001), while the reduction in those with malocclusion was not significant (32.8 vs. 24.0, p = 0.1258). 75.5% of those with normal occlusion met criteria for surgical success as defined by Sher et al. while success was only achieved in 33.3% of those with malocclusion (p < 0.01).

This study suggests patients with malocclusion may experience diminished efficacy to HNS therapy. This information may help identify individuals who are less likely to benefit from HNS therapy or who may require alternative (maxillomandibular advancement) or combination therapy (HNS with oral appliance).

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