Craniofacial Analysis of Lateral Cephalograms in Obstructive Sleep Apnea-An Exploratory Case-Control Study.

Background

The clinical value of lateral cephalograms for obstructive sleep apnea (OSA) risk assessment remains controversial, largely because previous case-control studies often lacked objective exclusion of OSA in control subjects and insufficiently controlled for confounding. This age-matched case-control study evaluated whether craniofacial characteristics differ between individuals with and without OSA and whether these craniofacial measurements independently predict OSA-related outcomes after adjustment for relevant confounders.

Methods

A total of 54 adults were included (27 with OSA and 27 without OSA). OSA was defined by poly(somno)graphy (apnea-hypopnea index [AHI] ≥ 5). Control subjects were prospectively recruited, and OSA was excluded through polygraphy (AHI < 5). Lateral cephalograms were used to assess six PAS levels (P1-P6), 16 hyoid- and soft palate-related parameters, and sagittal/vertical skeletal characteristics. Potential confounders were controlled for by adjustment for BMI and craniofacial skeletal pattern. The PAS measurements were defined as the primary endpoint; soft palate and hyoid-related variables were considered secondary exploratory endpoints. Statistical analyses included independent samples t-tests, multiple linear regression models, and sensitivity analyses adjusted for sex.

Results

Craniofacial skeletal characteristics did not differ between groups. PAS dimensions showed no significant intergroup differences and were not independently associated with AHI after adjustment, whereas BMI consistently emerged as the strongest predictor. Uvula length and thickness were significantly greater in the OSA group; however, neither parameter independently predicted AHI in regression models. In contrast, subjects with OSA exhibited a significantly more inferior/anterior hyoid position across multiple models. In the primary regression models, several hyoid-related variables were associated with AHI. However, these associations were attenuated in additional sensitivity analyses after adjustment for sex and were no longer consistently statistically significant. Sex was a relevant covariate in several models.

Conclusions

Static PAS measurements derived from lateral cephalograms provide no clinically meaningful information for OSA screening or risk stratification. Although several hyoid-related variables were associated with AHI in primary models, these associations were attenuated after adjustment for sex and should therefore be interpreted as exploratory. When lateral cephalograms are already clinically indicated, hyoid position may provide complementary anatomical information, but its independent predictive value remains uncertain.