Congenital posterior choanal atresia

Radiographic Diagnosis of Choanal Atresia Induced Prenatally with Triamcinolone in the Baboon ( Papio cynocephalus)

“…The accepted ernbryological explantation of choanal atresia in humans is failure of the buccopharyngeal membrane to rupture between the 35th and 38th day of fetal life. Nasal obstruction in 90%of reported cases is due to an osseous septum, while a fibrous membrane is present in the remainder [11]. In the reported cases, osseous obstruction is located a few millimeters rostral to the posterior edge of the hard palate and the septum can be 1-10 mm thick, whereas membraneous obstructions are generally located caudal to the bony obstructions.…”

“…an osseous septum, while a fibrous membrane is present in the remainder [11], In the reported cases, osseous obstruction is located a few millimeters rostral to the posterior edge of the hard palate and the septum can be 1-10 mm thick, whereas membraneous obstructions are generally located caudal to the bony obstructions. Associated orofacial anomalies, including high arched hard palate and increased thickness of the vomer bone and nasal septum, may further reduce the capacity of the nasal cavity and naso pharynx [14].…”

“…Positive contrast choanograms were performed, using a modification of the method described for human infants [11]. The animal was placed in the supine position, an infant feeding tube was introduced approximately 1 cm into the nasal fossa, and 1-5 cm3 of a thick, water soluble, iodinated contrast medium (Hytrast N [propyl-2:3-diol]-3:5-diiodo-4-pyridone and 3:5-diiodo-4-pyridone, Andre Guebert Laboratories, Paris, France) was slowly infused into the nasal fossa.…”