Effect of Mandibular Advancement Device Treatment on the Site-Specific Degree of Upper Airway Collapse During Drug-Induced Sleep Endoscopy.

Background: Mandibular advancement device (MAD) therapy is a non-invasive treatment for obstructive sleep apnea (OSA). Although the effect of MAD on OSA outcomes is widely known, its effect on the upper airway collapse degree remains poorly understood. This study aimed to assess the impact of MAD therapy on site-specific airway collapse degree during drug-induced sleep endoscopy (DISE). Methods: One hundred participants were recruited and underwent a baseline polysomnography. Overall, 69 participants with OSA (AHI 5-50 events/h) underwent DISE at baseline and with MAD set to 75% of maximal mandibular protrusion. Collapse degree (none, partial, complete) was evaluated at the palate, oropharynx, tongue base, hypopharynx, and epiglottis without and with MAD. Ordinal logistic regression was used to analyze changes in degree of collapse. Results: MAD therapy reduced collapse degree at the palate (OR = 5.92 [3.28; 10.66], p < 0.001), oropharynx (OR = 2.70 [1.48; 4.92], p = 0.001), tongue base (OR = 1.83 [1.32; 2.53], p < 0.001), and hypopharynx (OR = 2.90 [1.53; 5.48, p = 0.001), with no effect at the epiglottis (OR = 0.65 [0.42; 1.02], p = 0.058). Conclusions: MAD therapy reduces upper airway collapse at most anatomical levels, except at the level of the epiglottis. These findings confirm its therapeutic efficacy while underscoring the importance of identifying patients with residual or worsening collapse who may benefit from combined or alternative treatments.