Microtia Defined
Microtia, defined simply, is a deformity of the outer ear that is present at birth. There may or may not be an external ear canal. Microtia can range from no ear visible and no auditory canal (anotia and atresia) to having parts of the ear visible. Usually only one ear is affected, although both can be affected.It is a very common birth defect, happening in one of every 6,000 to 12,000 births. In some cases, it can even be identified prenatally. Definitive causes of microtia are unknown. However, studies that have been done have found possible genetic causes and associations with drugs such as thalidomide.
Microtia Types
There are four types or grades of microtia.
- Type I:Small but normal looking ear
- Type II: Moderately deformed external ear
- Type III: Only a little tissue visible
- Type IV: Anotia - no sign of any ear
Microtia - Hearing Loss
In microtia, the middle ear may be deformed, and conductive hearing loss of approximately 40 to 60 db may be present. If the microtia is bilateral and there is no ear canal, bone conduction hearing aids (such as the bone anchored hearing aid) can be used.Microtia Treatment
Microtia can be treated through surgery to repair the external ear. This surgery is usually done in early childhood, when the normal ear has grown to or is near the adult size. An alternative to surgery is to use an artificial ear prosthesis. Middle ear surgery may also be done if there is severe hearing loss in both ears. Even if there is only one ear affected, it still makes sense to do middle ear surgery because unilateral hearing loss negatively impacts children's academic performance and adults' earning potential.Microtia Support Groups
Although it is a mild condition, microtia/atresia does have some psychological impact, mostly from having a visible condition. Yahoo groups has an AtresiaMicrotia support group.Microtia Research
The medical knowledge on microtia is so advanced that researchers may want to seek out only the most recently published material. A PubMed.gov search on microtia turned up sample articles from journals on plastic reconstructive surgery.Sources:
J.E. Cho Lieu, Speech-language and educational consequences of
unilateral hearing loss in children, Archives of Otolaryngology-- Head and Neck Surgery. 130 (2004), pp. 524-530.
