What is microtia?
Microtia is a condition where one or both ears failed to form or only a small remnant of an ear formed during development. Most commonly, patients are born without an ear canal and only a small remnant of abnormal cartilage and an earlobe, which may be positioned abnormally on the face.
What causes microtia?
Many patients with microtia also have a condition called hemifacial microsomia. Microtia may occur alone, but most patients have findings suggesting they have a minor case of hemifacial microsomia. Researchers do not yet know for certain what causes hemifacial microsomia or microtia. The leading theory is that an abnormality or injury to an artery in the head during development leads to abnormal development of the affected structures. Most cases of microtia or hemifacial microsomia are not genetic or inherited.
What are the symptoms of microtia?
Patients with microtia have an obvious deformity of their external ear. In addition, patients may have an absent external ear canal and an absent or abnormal middle ear. These conditions result in hearing loss in the affected ear. Typically, patients with microtia still have the nerves needed to hear on the affected side, and hearing aids are helpful. Patients with hearing loss in one ear can hear, but often have difficulty locating sounds. Your child should be taught the importance of looking both ways when crossing the street.
How are patients with microtia evaluated?
It is critical for patients with microtia to be evaluated by an audiologists and a pediatric ENT specialist. It is critical to confirm that they have hearing in the unaffected ear and that ear infections and other conditions which may affect hearing in the normal ear are treated. Patients with unilateral microtia may benefit from hearing aids and patients with bilateral involvement need them to learn to speak normally. When your child is older, if a canalplasty is considered to open the ear canal, an otologist may recommend a CT scan to determine if their anatomy makes this possible.
Patients who have microtia as a result of a more significant case of hemifacial microsomia require a coordinated team of specialists. This includes a plastic surgeon, a pediatric ENT specialists, a pediatrician, a geneticist, an ophthalmologist, a pediatric dentist, an orthodontist, an audiologist, a speech therapist, and a social worker. All of these specialists will evaluate your child and coordinate a comprehensive plan for their care.
How is microtia treated?
The first priority in treated patients with microtia is to make sure they hear well enough to learn to speak. Your audiologist and pediatric ENT specialist will assist with this. Most patients wear a bone conduction hearing aid that is held in place with a soft elastic band. When patients are older they may be a candidate for a bone anchored hearing aid (BAHA) where an implant is placed so your child’s hearing aid can be worn without a headband. Some patients are a candidate for creation of an external ear canal, a procedure called a canalplasty. This procedure is performed by an otologist and consultation with this specialist will help you find if your child is a candidate for this surgery.
If you are considering either of these procedures, and desire your child to have ear reconstruction as well, please discuss them with your plastic surgeon. They are both valuable procedures, but if they are performed before ear reconstruction surgery they may increase the risk of complications or compromise the outcome of ear reconstruction.
Most patients with microtia can have an ear created for them around 8-10 years of age. By this time, most patients are big enough that there is enough cartilage in the ribs to create an entire ear and the children are mature enough to undergo the process. Most cases of microtia can be reconstructed in 2 operations. Many patients would benefit from a small “touch-up” operation afterward to maximize their result. More severe cases require 3 or 4 operations to complete the construction of a new ear.
The first operation in this process requires the surgeon to carve an ear from rib cartilage and place this where the missing ear should be located. The second operation is performed 6-12 months later and involves elevating the ear so it sticks out from the head. This is done using tissue taken from the scalp (TPF flap) or behind the ear and a skin graft taken from another location.