Systematic analysis of cephalometry in obstructive sleep apnea in Asian children

Objectives/Hypothesis: This study was designed to systematically analyze the relationship between a cephalometric analysis and the apnea-hypopnea index in a group of Asian children with obstructive sleep apnea. Study Design: Retrospective study. Methods: Data were collected from 56 children with obstructive sleep apnea who were between 3 and 13 years old. Each child underwent attended overnight polysomnography and cephalometry. We measured nine angles, 10 lines, and two ratios as well as adenoid size on each cephalometric film. Data included five segments of the upper airway: nasal cavity (segment 1), nasopharyngeal space (segment 2), retropalatal space (segment 3), retroglossal space and hyoid (segment 4), and oral cavity-related space (segment 5). Results: Four cephalometric anthropomorphic findings (Gn-Go-H, MP-H, MPH/GnGo, Ad/Na) were related to the apnea-hypopnea index. Three of the four parameters belonged to segment 4, indicating the importance of hyoid position in pediatric obstructive sleep apnea. Conclusions: This study showed that segment 4 was the most important segment affecting the apnea-hypopnea index. Most of the cephalometric parameters in segment 4 did not show a difference from the results of Caucasian groups, except that mandibular length and position appeared to have more positive findings in the Caucasian results. In segment 2, the apnea-hypopnea index was less affected by the skull base-related parameters in our data. The reason why the other segments appeared to play a lesser role in pediatric obstructive sleep apnea might due to the limitations of two-dimensional imaging. Further cephalometric studies with anterior-posterior view and on the differences between Caucasian and Asian children are mandatory.