The average rate of choanal atresia is 0.82 per 10,000 individuals. Unilateral atresia occurs more frequently on the right side. A slightly increased risk exists in twins. Maternal age or parity does not increase the frequency of occurrence. Five percent of patients have monogenic syndromes or conditions.
Choanal atresia occurs equally across races.
The nasal cavities extend posteriorly during development under the influence of the posteriorly directed fusion of the palatal processes. Thinning of the membrane occurs, which separates the nasal cavities from the oral cavity. Failure of this rupture results in choanal atresia. Although these choanae are not in the same location as the definitive choanae, which will eventually be located more posteriorly, it does explain the unexpectedly anterior extent of choanal atresia. A complete nasal and nasopharyngeal examination is performed using a flexible fiberoptic endoscope to assess the deformity.