Mouth breathing, "nasal disuse," and pediatric sleep-disordered breathing.

BACKGROUND: Adenotonsillectomy (T&A) may not completely eliminate sleep-disordered breathing (SDB), and residual SDB can result in progressive worsening of abnormal breathing during sleep. Persistence of mouth breathing post-T&As plays a role in progressive worsening through an increase of upper airway resistance during sleep with secondary impact on orofacial growth.

METHODS: Retrospective study on non-overweight and non-syndromic prepubertal children with SDB treated by T&A with pre- and post-surgery clinical and polysomnographic (PSG) evaluations including systematic monitoring of mouth breathing (initial cohort). All children with mouth breathing were then referred for myofunctional treatment (MFT), with clinical follow-up 6 months later and PSG 1 year post-surgery. Only a limited subgroup followed the recommendations to undergo MFT with subsequent PSG (follow-up subgroup).

RESULTS: Sixty-four prepubertal children meeting inclusion criteria for the initial cohort were investigated. There was significant symptomatic improvement in all children post-T&A, but 26 children had residual SDB with an AHI > 1.5 events/hour and 35 children (including the previous 26) had evidence of "mouth breathing" during sleep as defined [minimum of 44 % and a maximum of 100 % of total sleep time, mean 69 ± 11 % "mouth breather" subgroup and mean 4 ± 3.9 %, range 0 and 10.3 % "non-mouth breathers"]. Eighteen children (follow-up cohort), all in the "mouth breathing" group, were investigated at 1 year follow-up with only nine having undergone 6 months of MFT. The non- MFT subjects were significantly worse than the MFT-treated cohort. MFT led to normalization of clinical and PSG findings.

CONCLUSION: Assessment of mouth breathing during sleep should be systematically performed post-T&A and the persistence of mouth breathing should be treated with MFT.