Morphological analysis by lateral cephalography of sleep apnea syndrome in 53 patients.

To determine the morphologic characteristics of patients with sleep apnea syndrome (SAS), the facial skeleton, tongue area, soft palate area and upper airway area were examined on lateral cephalograms from 53 male patients with SAS. The SAS patients were divided into two groups according to their body mass index (BMI): Group N (BMI < 25, N = 23) and Group O (BMI > or = 25, N = 30). Fifty non-snoring adult men were used as a control (Group C). The mean BMI of all 53 patients with SAS was 26.2 +/- 3.1 kg/m2. The mean SNB was smaller in Group N (76.7 +/- 3.2 degrees) than in Group C (78.4 +/- 3.0 degrees). The mean airway area was markedly smaller in Groups N and O than in Group C. The tongue area was larger in Groups N (36.0 +/- 2.3 cm2) and O (39.3 +/- 2.7 cm2) than in Group C (33.3 +/- 3.4 cm2). There was a positive correlation (R2 = 0.670) in all subjects between tongue area and body weight. There was also a positive correlation (R2 = 0.656) between tongue area and the distance between the ANS and the base of the epiglottis in the 103 subjects, the base of the epiglottis being shifted to a posteroinferior position as a result of the enlarged tongue. The findings suggest that micrognathia is a morphological characteristic of the Japanese patients with SAS. Micrognathia and enlargement of the tongue and soft palate due to obesity, were considered to be involved in the narrowing of the airway in SAS patients.