Microtia and atresia: When ears don't develop fully

Microtia is a rare birth defect in which the external ear is not completely developed. It affects about one of every 3,800 babies born annually, according to the US Centers for Disease Control and Prevention.

Microtia usually occurs with atresia, also known as aural atresia, a condition in which the auditory ear canal is either underdeveloped, absent or closed. When this happens, a child will likely have severe conductive hearing loss in the affected ear.

Microtia and atresia almost always affect hearing and generally require ongoing medical care from a pediatric ear-nose-throat (ENT) specialist as well as an audiologist. It's more common in males than females, and is more likely to affect the right ear.

When the external ear is missing completely, it's known as anotia.

More: Understanding how we hear

What causes microtia and atresia?

Medical professionals aren’t sure exactly what causes microtia. It's theorized that it occurs during the first trimester of pregnancy when the soft tissues of the outer ear and middle ear are being formed. It's also linked to using skin products that contain retinol, or vitamin A, during pregnancy.

There are four grades of microtia:

• Grade 1—a smaller version of a typical ear with a smaller ear canal
• Grade 2—a partially formed ear with a narrow ear canal
• Grade 3—the external ear is missing but there may be a peanut-shaped structure made primarily of cartilage and earlobe; there is no external ear canal or ear drum (aural atresia)
• Grade 4—absence of the entire ear, known as anotia. 

Treatment options

Because this condition affects the outer ear, it is often accompanied by hearing loss. Affected children are also susceptible to ear infections and may become self-conscious about their condition as they grow older. Fortunately, microtia and atresia can usually be repaired, and the hearing loss treated.

Microtia 

Treatment options for microtia include:

• Rib graft construction, a procedure in which a surgeon creates an ear sculpture from the patient’s own rib cartilage.
• Medpor ear reconstruction, which involves a plastic ear frame that is covered with tissue grafted from the patient.
• Those who choose not to have reconstructive surgery might opt for a prosthetic ear, which is secured with magnets or adhesive.

The patient advocacy site Ear Community has in-depth information on microtia surgical procedures.

Atresia 

Treatment options for atresia include:

• Corrective surgery, in which the ear canal is widened or created.
• Surgery to implant a bone-conducting hearing system.

Surgical risks

One of the biggest risks of surgery is damage to the facial nerve, although modern surgical techniques have substantially lowered this risk. Other complications can include stenosis (stiffening), drainage from the ear and infection.

Medical professionals recommend parents wait until children are 5-7 years old to ensure compliance with postoperative care instructions.

Advocacy and awareness

Colorado native Melissa Tumblin was inspired to learn more about microtia when her daughter Ally was born with the condition. Through advocating for Ally's unique needs, she learned a great deal and wanted to find new ways to educate and support other parents. Tumblin subsequently founded Ear Community, an online support group and caring place for families affected by microtia and atresia.

November 9 is National Microtia Awareness Day, an observance created by Tumblin in the hopes of bringing public awareness to the rare congenital birth defect of the ear. 

Detecting hearing loss in babies and kids

Newborn hearing screenings can help detect hearing loss in infants even before parents bring their babies home from the hospital. When abnormalities such as microtia and atresia are apparent at birth, or when other hearing problems are detected during the screenings, medical professionals can help you decide which treatment options are best, and direct you to the resources needed to make the right decisions.

Children with hearing loss caused by ear abnormalities are best served through a team approach led by their pediatrician or ENT specialist. Pediatric audiologists have the equipment and education to evaluate hearing loss in babies and children. They will work with your pediatrician and medical specialists to implement the best treatment options so your little one has every social, educational and developmental advantage.

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