Cephalometric analysis of the obstructive sleep apnea syndrome.

The cephalometric measurements of 33 Finnish OSAS patients showed a fairly normal relationship between the base of the skull and the maxilla (SNA 82.3), whereas the mandible was slightly smaller than average (SNB 78.0). In 58% of the patients the mandible was significantly retrognathic and/or small in relation to the maxilla, even if dental occlusion was satisfactory. The sagittal lengths of the anterior cranial base and the maxilla were fairly normal. The hyoid bone was constantly situated more inferiorly and posteriorly than on average (MP-H 32.6). UPPP, genioplasty and advancement of the floor of the mouth and hyoid suspension were found to be effective in severe OSAS. The changes caused by the operation could best be verified cephalometrically by a more anterior position of the hyoid bone (average change of 11.1 mm).