CHOANAL ATRESIA

Choanal atresia is a congenital anomaly of the nasal choanae that is usually diagnosed at birth (respiratory distress in the neonate). There is an abnormality of canalization (or recanalization) resulting in total or partial obstruction to the posterior nasal airway.

Classification The original classification proposed by Fraser (1): 90% bony. 10% membranous. Brown et.al. (2) reviewed the literature and found no cases of pure membranous atresia. 29% bony. · 71% mixed bony-membranous.
Ultrasound All cases have bony abnormalities (narrowed nasal cavity, lateral impingement by the pterygoid bone, thickened abnormal posterior vomer with or without a central membranous connection) (3,4). Unilateral (50-60%) (1). Echogenic bony abnormality in the posterior nasal cavity. Nasal alae are patent. Color doppler during nasal breathing may demonstrate the absence of flow in the nasal cavity. · Diagnosis is usually made at postnatal CT scan ± nasal contrast.
Associated Syndromes 33% sporadic that is present in otherwise normal individuals (5). 66% are associated with a recognized syndrome: CHARGE Association (59% have bilateral choanal atresia). 9p Syndrome (6). Treacher Collins Syndrome. Aperts Syndrome.

REFERENCES

1. Fraser JS. Congenital atresia of the choanae. Br J Med 1910;2:1698-1701.
2. Brown OE, Pownell P, Manning SC. Choanal atresia: A new anatomic classification and clinical applications. Laryngodcopy 1996;106:97-101.
3. Brown OE, Burns DK, Smith TH et.al. Bilateral posterior choanal atresia: a morphologic and histologic study and computed tomography correlation. Int J Padiatr Otorhinolaryngol 1987;13:125-142.
4. Harner SG, McDonald TJ, Reese DF. The anatomy of congenital choanal atresia. Otolaryngol Head Neck Surg 1981;89:7-9.
5. Hall BD. Choanal atresia and associated multiple anomalies. J Pediatr 1979;95:395.
6. Shashi V, Golden WL, Fryberg JS. Choanal atresia in a patient with the deletion (9p) syndrome. Am J Med Genet 1994;49:88-90.