Endoscopy evaluation to predict oral appliance outcomes in obstructive sleep apnoea

The objective of this study was to determine the utility of nasoendoscopy of the upper airway as a predictor of the efficacy of oral appliance treatment in obstructive sleep apnoea (OSA). A total of 61 consecutive patients with moderate-to-severe polysomnographically diagnosed OSA were recruited for this study. Using nasoendoscopy, we prospectively assessed the velopharynx and oro/hypopharynx in each patient while awake and in the supine position. We measured cross-sectional area (CSA), and anteroposterior and lateral diameters of the airway before and after mandibular advancement, and expressed the changes in dimensions as expansion ratios (after/before). We then compared the measurements of responders and nonresponders with oral appliance treatment. The expansion ratio (median (interquartile range)) for the CSA was greater in responders compared with nonresponders in the velopharynx (2.9 (2.3-5.0) versus 1.7 (1.5-1.9), p<0.001) and in the oro/hypopharynx (3.4 (2.5-5.6) versus 2.4 (1.8-3.7), p<0.05). Baseline apnoea-hypopnoea index and the CSA expansion ratio of the velopharynx were independent predictors of oral appliance treatment outcome based on a multivariate logistic regression analysis. The estimated area under the receiver operator characteristic curve was 0.87 and the cut-off value of the expansion ratio was 2.00. These results indicate that nasoendoscopy may have significant clinical utility in predicting the success of oral appliance treatment.