Abstract
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 (∼2 or 3:1), is predominantly unilateral (∼70–90%),
and more often involves the right ear (∼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.
Keywords ear malformations - pinna - classification - syndromes
