Mandibular dimensions in children with obstructive sleep apnea syndrome

Objective: We hypothesized that mandibular size may play a role in the etiology of obstructive sleep apnea syndrome (OSAS) in children, since a smaller mandible may reduce airway size. We used magnetic resonance imaging to determine the mandible dimensions of children with OSAS. Design: Case control study. Setting: Tertiary-care pediatric hospital. Participants: Twenty-four subjects (mean age 4.9 ± 1.7 years) with mild to moderate OSAS (Apnea Index 3.5 ± 5.1), and 24 matched controls (mean age 4.9 ± 1.8 years). Intervention: Magnetic resonance imaging of the upper airway under sedation. Measurements: Eight measurements were obtained from a 3-dimensional segmentation of the mandible using 3DVIEWNIX software. Measurements included length, height, width, midsymphysis menti angle, angle of mandible, enclosure area, surface area, and volume. Descriptive comparisons using Student t test and multivariate analyses of variance were performed. Results: Individual measurement comparisons revealed no significant differences between groups. Multivariate analysis showed a lower bound of a 95% confidence interval for an effect size measure for "general mandibular size," including all 6 linear, the area, and the volume measurements, to be -0.25. Conclusion: Our study shows that a smaller mandible is not a feature in children with OSAS who do not have apparent craniofacial abnormalities.