Upper airway dimensions in adolescents with different craniofacial growth patterns: a retrospective cross-sectional comparison of independent samples from 2005 and 2020.

BACKGROUND

Craniofacial growth patterns and upper airway dimensions have been reported to be associated, but evidence regarding differences in airway morphology across growth patterns between different time periods remains limited. This study compared two independent adolescent samples collected in 2005 and 2020 to determine whether differences in upper airway morphology varied across craniofacial growth patterns.

METHODS

In this retrospective cross-sectional cephalometric study, 360 pre-orthodontic lateral cephalograms (180 from 2005; 180 from 2020) of Han Chinese adolescents (aged 10–15 years) from Hangzhou were analyzed. Cephalometric landmarks were used to identify growth patterns (vertical/horizontal/average) and to measure sagittal airway widths (nasopharyngeal: PNS-UPW, PNS-AD2; oropharyngeal: U-MPW; glossopharyngeal: TB-TPPW; laryngopharyngeal: V-LPW) and adenoid-nasopharyngeal ratios (A/N). Multivariate analysis of covariance (MANCOVA) adjusted for age, sex, and sagittal skeletal pattern was used to evaluate the effects of year, growth pattern, and their interaction. Adjusted mean differences with 95% confidence intervals were reported.

RESULTS

Significant year × growth pattern interactions were observed for nasopharyngeal and lower airway dimensions (p<0.05), indicating that differences between the two samples collected in 2005 and 2020 varied across craniofacial growth patterns. In the vertical growth pattern group, the 2020 sample exhibited significantly smaller nasopharyngeal widths (PNS-UPW: −3.10 mm; PNS-AD2: −2.75 mm) and reduced laryngopharyngeal width (V-LPW: −0.82 mm) compared with 2005. In the horizontal growth pattern group, narrower lower airway dimensions were observed in 2020 (TB-TPPW: −1.44 mm; V-LPW: −1.50 mm), while nasopharyngeal dimensions showed no significant differences. No significant differences were detected in the average growth pattern group. The A/N ratio was significantly higher in 2020 in the vertical (Δ = 0.067, p < 0.001) and horizontal (Δ = 0.044, p = 0.022) groups, but not in the average group (p = 0.266).

CONCLUSIONS

Differences in upper airway dimensions varied according to craniofacial growth patterns when comparing two independent adolescent samples. Adolescents with vertical growth patterns showed narrower nasopharyngeal and laryngopharyngeal dimensions in 2020, while those with horizontal patterns demonstrated reduced lower airway dimensions. These findings underscore the importance of considering craniofacial morphology in airway assessment.