The hyoid bone position and upper airway morphology among children with and without adenotonsillar hypertrophy: a cross-sectional study.

Background: Adenotonsillar hypertrophy (ATH) is a major cause of pediatric obstructive sleep apnea (OSA), potentially impacting craniofacial growth and development. Currently, whether children with ATH exhibit distinctive hyoid bone position and upper airway morphology remains uncertain. This research aimed to compare the hyoid bone position and upper airway morphology of children with and without ATH.

Methods: A total of 199 children aged 6-8 years were recruited for the study, and their pre-treatment lateral cephalograms were obtained. The size of the adenoids and tonsils on the lateral cephalogram was assessed based on Fujioka's and Baroni's methods for classification into groups: adenoid hypertrophy only (AHO) group, tonsillar hypertrophy only (THO) group, adenoid and tonsillar hypertrophy (AH + TH) group, and control group (CG). The position of the hyoid bone and upper airway morphology was analyzed using Dolphin Image Software.

Results: The distance between the hyoid bone and mentum was greater in the THO group compared to the AHO group (P = 0.005). Children in the AHO group exhibited a longer soft palate (SPL) compared to the THO group (P = 0.014), whereas the THO group displayed a reduced SPL in comparison to healthy controls (P = 0.008). The THO group showed a more inferior tongue position compared to children in the AHO group (P = 0.004). Subjects in the THO group exhibited significantly wider inferior airway space compared to healthy children (P < 0.001).

Conclusions: Adenotonsillar hypertrophy may be associated with hyoid bone position and upper airway morphology in children seeking for orthodontic treatment. In children with enlarged tonsils, the hyoid bone was positioned farther from the mentum than in those with enlarged adenoids. Conversely, children with enlarged adenoids had a longer soft palate compared to those with enlarged tonsils.