[Evaluation of upper airway and surrounding structures in patients with obstructive sleep apnea using cephalometry combined with Muller's maneuver].

PURPOSE: To evaluate the upper airway and surrounding structures under intraluminal pressure using cephalometry combined with Muller's maneuver in obstructive sleep apnea and hypopnea syndrome(OSAHS) patients with different severity. METHODS: Thirty-nine male patients were enrolled in our department during June 2011 to February 2012. Polysomnography(PSG) and anthropometric measurements data were recorded prior to the study. The lateral cephalograms of each patient were obtained during both the end-expiration phase and M u ller's maneuver phase. The patients enrolled were classified into 3 groups according to the results of apnea-hypopnea index(AHI), including mild group(n=11), moderate group(n=14), and severe group(n=14). Craniofacial and upper airway structures were measured in lateral cephalometry by application of Cassos 2001 computed aided measurement software before and after the patients practicing Muller's maneuver. The data was analysed using SAS 9.13 software package. RESULTS: Muller's maneuver had a great influence on the upper airway and surrounding tissue, including increased thickness of the uvula, reduction in the anteroposterior dimension of retropalatal and increased vertical distance of the hyoid bone to the mandible in all groups(P0.05). In addition, Muller's maneuver also had an impact on the length of the upper airway, which was more significant in severe cases. CONCLUSIONS: Cephalometry combined with Muller's maneuver can display how the intraluminal pressure function on the upper airway and surrounding tissues, and they also can distinguish some minor differences of the upper airway in patients with different security.