Utility of Cephalometry and Acoustic Pharyngometry for the Assessment of Moderate to Severe Obstructive Sleep Apnea Before Treatment in Childhood

Abstract

Purpose The ERS Statement dealing with childhood obstructive sleep apnea (OSA) declared that cephalometry and acoustic pharyngometry may be useful exams for the management of OSA. The objective of our cross-sectional study was to evaluate the correlations between the severity of OSA, namely obstructive apnea-hypopnea index (OAHI), and indices obtained from both acoustic pharyngometry and cephalometry in children referred for OSA treatment. Methods Children referred for treatment of their moderate to severe OSA (AHI ≥ 5/hour) underwent acoustic pharyngometry in sitting and supine positions (measurement of pharyngeal volume and calculation of estimated pharyngeal compliance) and cephalometry (measurement of Frankfort Mandibular plane Angle: FMA and Frankfort Mandibular Incisal Angle: FMIA, hyoid bone distance to mandibular plane). Results Two hundred and five consecutive children were enrolled (mean age ± SD: 11.2 ± 3.7 years, 73 females, type 1 OSA “enlarged tonsils”: 55 children, type 2 “obese”: 80, type 3 “syndromes”: 70). In a multiple regression analysis, only FMA and hyoid bone distance remained independently linked to OAHI (adjusted r2 of the model: 0.12, p< 0.001, weak explanatory power). The FMA angle allowed differentiating normodivergence (21°< FMA < 29°: 41% of the children), hyperdivergence (FMA ≥ 29°: 32%), and hypodivergence (≤ 21: 27%). The participants with hyperdivergence were younger, less obese, and had a longer lower face (adenoid facies). In a multiple regression analysis, only height and FMIA remained independently linked to pharyngeal volume (adjusted r2 of the model: 0.32, p<0.001, moderate explanatory power). Conclusion Childhood OSA can be associated with hypodivergence. Its severity is linked to craniofacial morphology, and cephalometry provides additional endotypic information in selected children.