Upper airway and its surrounding structures in obese and nonobese patients with sleep-disordered breathing

The objective was to understand the pathophysiological relationship between obesity and sleep-disordered breathing by using cephalometry with the Muller maneuver.

A prospective study.

One hundred habitually snoring men were evaluated for sleep-disordered breathing at the Sleep Center of Chang Gung Memorial Hospital (Taipei, Taiwan). Each subject received overnight polysomnography and two lateral cephalograms at the end-expiration phase (L1) and the Muller maneuver (L2), respectively, to evaluate the facial skeleton and the upper airway and its surrounding structures (soft palate, tongue, epiglottis, and hyoid bone). After excluding 14 patients from the study because of jaw opening during cephalometry, 86 (39 nonobese and 47 obese) patients with sleep-disordered breathing were enrolled.

Patients with varying degrees of obesity significantly differed in terms of the facial skeleton and the structure and function of the upper airway and its surrounding structures. The Muller maneuver caused dynamic changes in the hypopharyngeal airway and position of the tongue, and these dynamic changes were related to the pathogenesis of sleep-disordered breathing for the two groups (nonobese and obese patients). The regression model generated for the nonobese group revealed that the apnea hypopnea index was significantly related to the pharyngeal length (L2) and the soft palate thickness (L1). In contrast, the regression model generated for the obese group revealed that the apnea hypopnea index was significantly related to the soft palate (length [L1] and dynamic position change), the hyoid position (vertical [L1] and horizontal [L2]), the tongue (dynamic position change), and body mass index.

Cephalometry with the Muller maneuver may provide further insight into the pathogenesis of sleep-disordered breathing for the two groups of patients (nonobese and obese patients).