Congenital Auricular Malformations: Description of Anomalies and Syndromes

Half of the malformations in the ear, nose, and throat region affect the ear. Malformations of the external ear (pinna or auricle with external auditory canal [EAC]) are collectively termed microtia. Microtia is a congenital anomaly that ranges in severity from mild structural abnormalities to complete absence of the external ear (anotia). Microtia occurs more frequently in males (approximate to 2 or 3:1), is predominantly unilateral (approximate to 70-90%), and more often involves the right ear (approximate to 60%). The reported prevalence varies geographically from 0.83 to 17.4 per 10,000 births. Microtia may be genetic (with family history, spontaneous mutations) or acquired. Malformations of the external ear can also involve the middle ear and/or inner ear. Microtia may be an isolated birth defect, but associated anomalies or syndromes are described in 20 to 60% of cases, depending on study design. These generally fit within the oculo-auriculo-vertebral spectrum; defects are located most frequently in the facial skeleton, facial soft tissues, heart, and vertebral column, or comprise a syndrome (e.g., Treacher Collins syndrome). Diagnostic investigation of microtia includes clinical examination, audiologic testing, genetic analysis and, especially in higher grade malformations with EAC deformities, computed tomography (CT) or cone-beam CT for the planning of surgery and rehabilitation procedures, including implantation of hearing aids.