Microtria Atresia



Microtia (meaning 'Small ear') is a congenital deformity of the outer ear. Over 90 % of the time, microtia is unilateral, meaning only one ear is affected, but it can also be bilateral, affecting both ears. Boys are affected more than girls, and in unilateral microtia, the right side is affected more than the left. Microtia occurrence in the general population is approximately one in 8,000 globally, but ranges wildly depending on ethnic group in question -- from less than one in 1000 in some indigenous groups in Mexico, the US and South America, to one in 2100 in the Japanese/Korean community, to 1 in 20,000 in the overall Caucasian community.

There are four grades of microtia:

  • Grade I: A slightly small ear with identifiable structures and a small but present external ear canal

  • Grade II: A partial or hemi-ear with a closed off or stenotic external ear canal producing a conductive hearing loss

  • Grade III: Absence of the external ear with a small peanut vestige structure and an absence of the external ear canal and ear drum

  • Grade IV: Absence of the total ear or anotia.

Grade III is most common, and can be corrected by surgery.