Obstructive sleep apnoea syndrome: results and conclusions of a principal component analysis.

A cephalometric analysis according to Hasund, supplemented by special obstructive sleep apnoea syndrome (OSAS) parameters, was performed on 169 patients who had been referred from the sleep laboratory. Statistical analysis showed a correlation between specific cephalometric landmarks including posterior airway space (PAS), a soft palate length, hyoid position and posterior growth development of the mandible and OSAS severity. A principal component analysis differentiated between four subgroups of OSAS patients: (1) orthognathic obese subjects; (2) patients with a long soft palate and low-positioned hyoid; (3) retrognathic patients with narrow PAS; and (4) prognathic ones. Lateral cephalometry is an important contribution to OSAS diagnostics and oral and maxillofacial therapy procedures.