Abstract:

Objective To evaluate the changes in upper airway and surrounding structures under intraluminal pressure using cephalometry with Müller’s maneuver in obese and overweight obstructive sleep apnea and hypopnea syndrome(OSAHS) patients and non-obese controls. Methods Thirty-nine male patients were enrolled, anthropometric measurements and polysomnography data were collected prior to the study. Lateral cephalograms of each patient were obtained either at the end-expiration phase or the Müller’s maneuver phase. The patients included in the study were classified into two groups according to the body mass index(BMI). The BMI of patients <24 kg•m-2 was regarded as normal group, including 12 cases; while the obese group includes 27 cases. Craniofacial and upper airway structures were measured in lateral cephalometry using Cassos 2001 computed aided measurement software before and after the patients’ practicing the Müller’s maneuver. Results Two groups are similar in the craniofacial hard bony structures. However, when compared with the upper airway and surrounding structures, the obesity group exhibits a wider anterior-posterior dimension of upper airway, especially significant in retropalatal, tip of the palatal, retroglossal area. In addition, the obesity group shows a more collapsible airway than the controls after practicing the Müller’s maneuver. Conclusion The pathogenesis of OSAHS in obese patient may different from the patients of normal weight. The increased compliance to negative intraluminal pressure may predispose to the onset of OSAHS with obese status.

Key words: cephalometry, obstructive sleep apnea and hypopnea syndrome, obesity, Müller’s maneuver