The severity of microtia is referred to in 4 grades:
- Grade I: A structurally-intact, slightly small ear and a small external ear canal
- Grade II: A partial ear; in this grade, the external ear canal is closed off, resulting in conductive hearing loss
- Grade III: The absence of an external ear with a small peanut vestige structure and an absence of the external ear canal and ear drum
Grade IV: Complete absence of entire ear structure
Although microtia itself does not present problems with development, the level of hearing loss caused by the ear deformity can. Occasionally, a child with microtia can have a malformation of the inner ear, which leads to a sensorineural hearing loss. Sensorineural hearing loss is caused by a problem in the inner ear, the cochlea. Malformation or problems with the cochlea cannot be corrected by surgery. Rather they are treated with hearing aids. If a child with sensorineural hearing loss goes untreated, the child can struggle with speech and might require speech therapy.
You will probably have many questions concerning your child’s well being, development, and hearing. At the Yale Craniofacial Program, our team will answer all your questions and thoroughly explain what you can expect based on your child’s unique situation.
Causes of Microtia
Microtia occurs in 1 out of about 8,000 to 10,000 births and generally has no known cause, including genetics. In some cases, research has linked taking Accutane in pregnancy with microtia. Otherwise, there is nothing the mother or doctors could have done to prevent the ear deformity.
Microtia can happen alone or as a part of another syndrome, such as Treacher Collins and hemifacial microsomia.
It is natural to wonder if you will have another baby with microtia. The chance of having another baby with microtia is 1 in 6,000. Because there is no link to genetics or something that the mother did while pregnant, there is not necessarily an increased risk in having multiple children affected by microtia. Although there is currently no genetic testing for microtia or a direct genetic link, a geneticist can discuss with you the chances of having another baby with the same birth defect.
Features of Microtia
The way your child’s ear looks will vary by the severity of the defect:
- Grade I: The external ear is small but the outer part retains most of its normal structure.
- Grade II: The outside of the ear might be shaped like a hook, an S, or a question mark.
- Grade III: The outer ear is soft tissue without any cartilage and has an abnormal appearance.
- Grade IV: There is no outer ear.
The level of hearing generally depends on the level of microtia. Even children with microtia on both sides can have some level of hearing. An ear, nose, and throat surgeon (ENT) can assess the level of hearing and prescribe hearing aids, including bone-anchored hearing aids.
Because your child’s condition may be a symptom of a more complex syndrome, we use 3D CT imaging to provide a diagnosis more quickly and with more accuracy than ever before. Traditional CT scans provide black and white, one-dimensional scans, while advanced 3D imaging technology provides colored, multidimensional images that allow us to see the specific characteristics of your child’s condition. In this way, we can better understand how your child’s birth defect will specifically impact his or her health and development.
This list should be used as a guideline. Not every symptom is included. If your child has one or more of these symptoms, it does not mean that he or she has microtia. If you are concerned that your child might have microtia, please make an appointment with your child's doctor.
Treatments for Microtia
Treatment for microtia is generally two fold:
- Improve the quality of hearing
- Improve the visual appearance of the outer ear, also called auricular reconstruction
By 5 or 6 years old, a CAT scan can be done of the middle ear to find out the level of its development. This scan will help determine if your child is a candidate for surgery to improve his or her hearing.
Treatment options for auricular reconstruction include:
- Rib Cartilage Graft Reconstruction: This technique uses cartilage from your child’s rib cage. This ensures that the reconstructed ear grows with your child. Generally, this surgery is performed when the child is 8 years old – around the time the child has enough donor tissue in the rib cage.
- Prosthetic Framework Method: In this procedure, surgeons use a polyethylene plastic implant to reconstruct the ear. This surgery can start at age 3 as an outpatient without hospitalization. A porous framework in the implant allows your child's own tissue to grow into the material and their own tissue flap. A new ear is constructed in a single surgery. Sometimes a follow-up surgery is required for minor adjustments.
- Ear Prosthesis: In cases where other treatments aren’t successful or possible, a prosthetic ear is custom made for your child to mirror the unaffected ear. They are typically made of silicone, which is colored to match your child's skin and can be attached using an adhesive or titanium screws.
- Simulate the outcome of proposed surgical plans and adjust any discrepancies before surgery
- Follow and monitor your child’s condition during the post-surgical healing process
- Monitor your child’s long-term development