This topic provides information about microtia.
What is microtia?
Microtia is a congenital deformity of the outer ear (pinna). The term congenital means that it is present at birth. The pinna of the ear is underdeveloped or completely absent, called anotia.
Microtia-anotia can affect one ear (unilateral) or both ears (bilateral).
Four grades are used to classify the severity of the microtia:
- Grade I: The ear canal is small but present and the structures of the pinna are identifiable but not completely developed.
- Grade II: The ear canal is closed and the pinna is partially developed.
- Grade III: No ear canal, ear drum or pinna, with a small appendage of skin in it’s place. This is the most common type of microtia.
- Grade IV: Absence of the whole ear, also called anotia.
What causes microtia?
Microtia occurs when the ear does not fully develop when the embryo is in the womb. The reason for this malformation is unknown.
Microtia can also be linked to a spectrum of syndromes, particularly hemifacial microsomia, Goldenhar syndrome, and Treacher-Collins syndrome.
Some have theorized that the medication, Accutane, is linked to microtia if the mother is taking it during pregnancy.
You have a greater chance of getting microtia if you are male.
What are the symptoms?
Symptoms of microtia include a moderate to severe conductive hearing loss in the affected ear. In most microtia cases, the inner ear remains unaffected, meaning the hearing organ (cochlea) and hearing nerve function normally.
Since the sound cannot reach the inner ear because of the deformed and/or missing ear canal, the child will not hear normally out of the affected ear.
How is microtia diagnosed?
Microtia is easily diagnosed by the presence of a missing or deformed ear at birth.
The hearing loss can be diagnosed in infancy using an Auditory Brainstem Response (ABR) test. If the inner ear is unaffected, the test will be normal.
A CT Scan can also be performed to determine if the structures of the middle ear are affected. This may be necessary to determine whether surgical options would be beneficial for improving hearing.
How is it treated?
There are several options for treating the hearing loss for a child with microtia, specifically if the hearing loss is solely conductive. The Audiologist will work with your child’s Otolaryngologist and Pediatrician to inform you of your child’s options for improving their hearing. These can include the following rehabilitation devices:
- Osseointegtrated hearing device to include the Cochlear Baha or the Oticon Ponto Pro
- Sophono bone-anchored device
- Med-El Soundbridge and Bonebridge
Before the invention of bone-anchored hearing devices, a procedure called atresiaplasty was the only option to attempt to improve hearing. This involves surgically opening the ear canal.
Surgical reconstruction of the ear or the use of an ear prosthetic can be done to improve the cosmetic look of the outer ear.
Does microtia cause lasting problems?
In cases of unilateral microtia, there are little to no lasting effects. Even if no hearing device is used, the child should still develop normal speech and language because of the normal hearing in the unaffected ear.
In cases of bilateral microtia, the child will have significant speech and language delays if the hearing loss is left untreated.