Patients characteristics.

Data are presented as mean±SD for data with normal distribution.
AHI: apnea/hypopnea index, BMI: body mass index, ESS: Epworth sleepiness score.
GH-d: distance between bilateral greater horns, LH-d: distance between bilateral lesser horns, AP: distance from most anterior end of hyoid arch to GH-d, GH-LH, Rt: distance from the right greater to right lesser horn, GH-LH, Lt: distance from the left greater to left lesser horn, H-angle: distance from greater to lesser horn, and anterior angle between bilateral extensive lines from greater to lesser horn.