micrognathismdistraction osteo-genesistracheostomyrespiratory systemairway obstructionobstructive sleep apneaenteral nutritiondeglutition disordersretro-spective studiesMANDIBULAR DISTRACTION OSTEOGENESISPIERRE-ROBIN-SEQUENCEFEEDING DIFFICULTIESAIRWAY-OBSTRUCTIONCHILDRENSLEEPMANAGEMENTMICROSOMIAINFANTSGROWTH