Mandibular advancement for obstructive sleep apnea: relating outcomes to anatomy

This study provides insight into the response and cure rates of oral appliances (OAs) in patients with primary retropalatal, retroglossal, or retroepiglottic obstruction, as well as the effect of minimal cross-sectional area on the overall decrease in the apnea-hypopnea index (AHI) across all anatomical locations of collapse.

To examine the role of regional upper airway obstruction measured with acoustic pharyngometry as a determinant of OA success.

This retrospective case-series included patients with obstructive sleep apnea-hypopnea syndrome at a tertiary care center.

Patients were fitted with a custom OA between July 1, 2011, and January 1, 2012.

Regions of maximal upper airway collapse were determined on acoustic pharyngometry: retropalatal, retroglossal, or retroepiglottic. Apnea-hypopnea index improvement at titration polysomnography was assessed against regional collapse.

Seventy-five patients (56 [75%] men; mean [SD] age, 49.0 [13.6] years; mean body mass index [calculated as weight in kilograms divided by height in meters squared], 29.4 [5.2]; and mean AHI, 30.6 [20.0]) were assessed, and data were grouped on the basis of region of maximal collapse at pharyngometry (retropalatal in 29 patients, retroglossal in 28, and retroepiglottic in 18). The overall reduction in AHI at OA titration showed no significant difference between groups. There was no significant difference in the response rate to treatment, defined as more than 50% AHI reduction plus an AHI of less than 20 (response rate, 69% for retropalatal, 75% for retroglossal, and 83% for retroepiglottic collapse; P = .55) or the cure rate, defined as an AHI of less than 5 (cure rate, 52% for retropalatal, 43% for retroglossal, and 72% for retroepiglottic collapse; P = .15). The correlation between minimal cross-sectional area and response trended toward significance (r = 0.20; range -0.03 to 0.41; P < .10).

Oral appliance therapy achieves reasonable response and cure rates in patients with primary retropalatal, retroglossal, or retroepiglottic obstruction at the time of initial titration polysomnography. However, success is not predicted by identification of the region of maximal upper airway collapse measured with acoustic pharyngometry.