Clinical variables determining the success of adenotonsillectomy in children with Down syndrome.

Objectives: To evaluate the evolution of polysomnographic parameters of children with Down syndrome and obstructive sleep apnea syndrome submitted to adenotonsillectomy and the interaction of comorbidities on therapeutic outcome.

Methods: Ninety patients with Down syndrome and habitual snoring were identified between 2005 and 2015 in a Pediatric Otorhinolaryngology Clinic. Parent's complaints were evaluated by the test of equality of two proportions. Wilcoxon test was used to examine pre- and post-operative polysomnographic differences. Mann-Whitney test evaluated the influence of comorbidities. A p < 0.05 was considered significant.

Results: A total of 27 patients met the inclusion criteria (55.6% patients were males; mean (SD) age were 6.7 (3.6) years (range, 1.5-16 years). Significant improvement of parent's complaints (p < 0.001), arousal index (p = 0.045), and minimum oxygen saturation were observed post-adenotonsillectomy (p = 0.034). Adenotonsillectomy was able to resolve obstructive sleep apnea syndrome in 29.6% of children with Down syndrome. Nineteen patients (70.4%) remained with obstructive sleep apnea syndrome and 44.4% showed a reduction of at least 50% of obstructive apnea-hypopnea index. Central apnea index post-adenotonsillectomy was worse in patients with heart disease (p = 0.022). Sleep efficiency (p = 0.031), N1 sleep stage (p = 0.001), apnea-hypopnea index (p = 0.023), and central apnea index (p = 0.008) were worse after surgery in patients with hypothyroidism. Patients with severe OSAS showed significant improvement in polysomnographic parameters after surgery.

Conclusion: Although adenotonsillectomy improved symptoms and objective sleep data in children with Down syndrome, it was not able to resolve obstructive sleep apnea syndrome in most patients. Congenital heart diseases and hypothyroidism may affect the outcome.