Comparison of cephalometric analysis with ethnicity in obstructive sleep apnea syndrome.

Many studies have documented significant craniomandibular abnormalities in obstructive sleep apnea syndrome (OSAS) patients. Recent literature clearly describes the cephalometric abnormalities commonly associated with OSAS. Studies have not evaluated specific cephalometric abnormalities that may contribute to OSAS by various ethnic groups. Data were collected on 48 patients (20 Caucasian, 15 Black and 13 Hispanic) with completed cephalometric analysis and polysomnography. Cephalometric landmarks, angles and measurements [angle measured from sella to nasion to subspinale point (SNA), angle measured from sella to nasion to supramentale point (SNB), difference between SNA and SNB (ANB), perpendicular distance from gonion to gnathion to hyoid (MP-H), distance from posterior nasal spine to tip of soft palate (PNS-P) and posterior airway space (PAS)] commonly used in the evaluation of OSAS patients were recorded. Measurements were normalized by dividing the observed value by the mean value for the ethnic group. Statistically significant differences in normalized SNA and SNB appeared in the Black and Hispanic groups when compared to the Caucasian group. For both SNA and SNB, Blacks averaged approximately 3.5% above their ethnic mean, whereas Hispanics averaged 1.8-2.8% below their ethnic mean. There was a statistically significant correlation between respiratory distress index (RDI) and MP-H. These baseline cephalometric differences in the ethnic groups studied suggest that surgical intervention might be approached differently in various ethnic groups. Further studies that evaluate the surgical success achieved by various procedures among different ethnic groups may help define surgical protocol in various ethnic groups for OSAS.