## 4 Discussion  
The main findings of this article rely on the AHI values pre and post RME with or without previous AT. Related to the primary outcome, the AHI in 102 children with a mean age of \(6.7\pm 1.3\) with obstructive sleep apnea decreased after RME treatment. The AHI improved from a M \(\pm\) SD of \(7.5\pm 3.2\)/h to \(2.5\pm 0.2\)/h. A 66.1% improvement in AHI was detected. The most successful group based on percentage reduction of the AHI were the 23 children in the study of [PERSON] et al. [34] with a 97.7% compared to the least successful where the percentage was 24.4% ([PERSON] et al.) [17]. Aside from this study, RME demonstrated the capacity to provide at least a 60.7% reduction in the AHI value. In the meta-analysis by [PERSON] et al. [32], similar outcomes were described: AHI in their 313 patients demonstrated a 70% improvement. The pre RME apnea-hypopnea index was \(7.5\pm 0\) 3.2/h, which is considered by the ASSM to be a mild-to-moderate OSAS. A severe OSA was identified before RME therapy on [PERSON]'s case report [36], with an AHI value of 18.9/h and on [PERSON] et al. [34] with an AHI value of \(12.2\pm 2.6\)/h. Moderate-to-severe OSAS were observed by [PERSON] et al. [13] and by [PERSON] et al. [35] while a moderate OSA was analyzed in the studies of [PERSON] et al. [31] and [PERSON] et al. [17]. Regarding the secondary outcome, to evaluate the pre and post-RME AHI index outcomes based on tonsil size and if the patient underwent a prior AT or not, it was possible to observed a higher AHI change in patients with no tonsils (83.4%) and small tonsils (97.7%) in comparison with children characterized by large tonsils (56.4%). Similar outcomes were examined in the study of [PERSON] et al. [32] that indicated a higher AHI change in patients with no tonsils (85%) and small tonsils (95%) when compared to children with large tonsils (61%). In fact, in a sample of 33 children with large tonsils their AHI decreased from a M \(\pm\) SD of \(11.4\pm 11.6\)/h to \(4.5\pm 3.6\)/h after RPE. The authors of this study concluded that patients with large tonsils might continue to exhibit oropharyngeal obstruction although there are improvements at the level of the palate, underlying the importance of preceding the RPE with AT. [PERSON] et al. [35] stated that none of the children presented normal results after treatment 1 (only surgery or only orthodontics), with the exception of one case. Thirty children underwent treatment 2 with an overall significant improvement. This confirms the importance of an interdisciplinary approach on the treatment of children with OSAS, since both RME and AT are needed treatments. Nevertheless, there was no significant difference in the amount of improvement noted independently of the first treatment approach. [PERSON]'s case report [36] reported as well that performing exclusively AT is not sufficient to treat OSAS. Failure of RME treatment alone was observed in the study of [PERSON] et al. [13] only in an 8-year-old girl in whom the AHI did not change after 12 months of RME treatment, but instead increased after 24 months. The authors reported that she had tonsil hypertrophy, which is congruent with the secondary outcome of this meta-analysis. Related to the risk of bias, it may lie on the choice of literatures. [PERSON]'s study is a case report, and some others are included the literature from same authors. Nevertheless, this analysis demonstrated a general reduction of the daytime and nighttime symptoms of OSAS after RME therapy with or without previous AT. An overall improvement in the AHI index and in the symptoms related to sleep-disordered breathing was seen in the six articles used for this metanalysis. In fact, in [PERSON] et al. prospective case series [34], 23 children were evaluated with clinical interviews and evaluation, completion of the Pediatric Daytime Sleepiness Scale (PDSS) or Epworth Sleepiness Scale (ESS) and the Italian translation of the Pediatric Sleep Questionnaire.