Abstract
Introduction: The prevalence of obstructive sleep apnea (OSA) in children with Down syndrome (DS) ranges between 30 to 100%. The complexity of the pathogenesis of OSA in these children is illustrated by a high incidence of residual OSA after adenotonsillectomy (AT). The aim of this study is to get a better insight in this pathogenesis through a detailed analysis of the upper airway (UA) by functional respiratory imaging.
Methods: Children with DS diagnosed with OSA by polysomnography were prospectively recruited. All underwent an ultra-low dose CT scan of the UA. 3D reconstructions were built from these images and were further analyzed using computational fluid dynamics. A second polysomnography was performed 6 months after treatment.
Results: Eighteen children without previous UA surgery were included (8 boys; mean age 5.4±7.5 years with a median obstructive apnea/hypopnea index (oAHI) of 17.5/hr (range 3.5-61.3)). The majority of subjects had their smallest cross-sectional area located in the overlap region between adenoids and tonsils and in the upper trachea. Tonsillar hypertrophy was inversely related to UA volume derived by imaging. 18 patients underwent tonsillectomy or AT and a post-treatment polysomnography. Sixteen of these 18 patients had a post-treatment oAHI > 2/hr. The improvement in oAHI between the first and second sleep study was correlated with baseline oAHI (r=0.83;p<0.001) and a trend was observed with UA resistance (r=0.46;p=0.056).
Conclusions: This pilot study in children with DS and OSA demonstrated correlations between UA volumes and tonsillar hypertrophy. The value of this technique to predict outcome of UA surgery in DS patients, needs to be investigated further.
- Copyright ©ERS 2015
