[Clinical aspects of choanal atresia]

Clinical examination was performed on 10 patients with recently treated choanal atresia, 8 unilateral and 2 bilateral cases. All patients showed an asymmetrical facial skeleton, which could be classified as hemifacial microsomia, although sometimes in a rather subclinical form. In all unilateral cases of choanal atresia hypoplasia of the facial skeleton was manifest on the affected side. These cases did not reveal that choanal atresia can occur without any abnormality in the facial skeleton. Hemifacial microsomia is not only a clinical entity, but also has a distinct pathogenesis. In early embryonic development a trauma occurs in the first or second branchial arch, which causes focal mesenchymal destruction, and this is thought to present the pathogenesis of hemifacial microsomia. Choanal atresia did not always occur with associated orthodontic abnormalities. Clinical examination, however, revealed transversal maxillar compression at the affected side in three out of eight unilateral cases.