Limitations of the Study:
Our study has some limitations. First of all, it is a retrospective study. However, in some instances, when clinical trials are not possible, retrospective studies are available to compare different treatments, define prognostic factors, helpful to assess the feasibility of prospective studies and to help in their design. Secondly, as only two sizes of flexible bronchoscopes (with outer diameters 3.8 and 4.8 mm) were available in our centre, we could not evaluate young infants and newborns with bronchoscopic examination and that may affect the results hence incidence of malacia. Thirdly, after starting a treatment type the patients were evaluated only with clinical improvement to figure out the effect of the treatment modality and to decide to terminate it. However, determining the effect of the treatment with bronchoscopic evaluation might be more valuable and objective.