Choanal atresia is a congenital disorder where the back of the nasal passage (choana) is blocked, usually by abnormal bony or soft tissue (membranous) due to failed hole development of the nasal fossae during prenatal development. It causes persistent rhinorrhea, and with bilateral choanal atresia, an obstructed airway that can cause cyanosis and hypoxia. Choanal atresia is diagnosed based on the inability to place a nasal catheter, and radiology results (particularly CT scans)...