[Examination of low palatal arch with long low hanging soft palate in obstructive sleep apnea syndrome and cephalometry].

In order to clarify morphological abnormalities of the upper airway in patients with obstructive sleep apnea syndrome (OSAS), and to predict the severity as well as the effect of surgery, we statistically examined the relationship between the degree of low palatal arch and the result of cephalometry in 45 adult male patients with OSAS who underwent uvulopalatopharyngoplasty. The patients were divided into 3 types, A, B and C, according to the degree of low palatal arch on inspection, and type C was regarded as having a low palatal arch with a long low-hanging soft palate. It was found that (1) type C patients showed a higher preoperative apnea index and lower minimal blood oxygen saturation, suggesting a serious condition. (2) In type C patients, the long axis (PNS-H) of the airway was larger, and the oral area was smaller. The area of the entire tongue, especially the upper half of the tongue, was larger than that in patients of other types. Type C patients were further divided into 3 subtypes: (1) those with a substantially long low-hanging soft palate; (2) those with a long low-hanging soft palate and large tongue; and (3) those in whom the large tongue is the main factor for the apparent low-hanging soft palate. These subtypes should be confirmed by cephalography before treatment for effective surgical results.