What are microtia and atresia?
Microtia is the term used to describe malformation of the external part of the ear (the pinna). Microtia varies in severity from minor changes where the ear may only be smaller than expected, to complete absence of the pinna. Absence of the ear canal (external auditory meatus) is called atresia.
Microtia is often associated with atresia because the outer ear and ear canal develop together during pregnancy.
Microtia and atresia are conditions people are born with (congenital). They can affect one (unilateral) or less frequently, both ears (bilateral). They can occur alone, alongside other craniofacial anomalies, or as part of a syndrome. Common syndromes which may involve microtia are goldenhaar, treacher-collins or hemifacial microsomia. When occurring alone the exact cause is not known but more research is emerging.
What does this mean for me or my child?
People with microtia and atresia do not have a normal pathway for sound to reach the inner ear on the affected side. When there is no outer ear canal or a very narrow ear canal, the ear drum and middle ear can be affected too.
Usually, sound is transmitted through the middle ear by the bones of hearing, but in microtia and atresia this may not be possible. However, even though the outer and middle ear can be affected by the condition, often the inner ear is healthy.
What are the management options?
Sometimes hearing can be restored by bypassing the parts which aren’t present or working properly - taking sound directly to the inner ear.
If one ear is affected, often the other ear can hear normally. This will usually be confirmed with hearing tests at a young age. Stimulation to the affected side is still recommended and we advocate aiding on that side as soon as possible. More and more research and our experience as a team supports both ears having access to sound. This helps with listening fatigue and maximises speech and language development.
In some cases, both ears can be affected, it is vital babies and children are fitted with hearing aids to help them develop speech and language as soon as possible. This is initially a bone conduction device which bypasses the blocked outer and middle ear, taking sound directly to the inner ear. Small children can have this held in place with a headband. Older children and adults can have more permanent alternatives.
At St Thomas’ Hospital's hearing implant centre, we can offer more permanent solutions such as implantable bone conduction hearing devices and middle ear implants. The hearing rehabilitation options will be discussed within our team of experts to offer your child the most appropriate hearing solution tailored to their specific needs and depending upon the parts of the hearing pathway that are affected. This field is developing all the time and our specialists have access to the newest available solutions.
Options include:
- bone conduction implants (percutaneous – abutment going through the skin, this used to be called BAHA (a bone anchored hearing aid)
- bone conduction implants (transcutaneous – skin intact with magnets keeping the internal and external equipment connected)
- middle ear implants to directly vibrate the bones of hearing or stimulate the inner ear
The other important consideration is the appearance of the outer ear.
There are two main possibilities for improving this:
- surgical reconstruction of the outer ear
- creation of a prosthetic outer ear
Our team has specialists with the skills and equipment to provide a suitable longterm solution for your child with either option.
Specialist microtia and atresia clinic
Our clinic is held 4-5 times per year. Before the clinic, we present an information session for patients, parents and families so we can explain more about the condition and the treatment options. The clinic involves meeting all the specialists together which enables us to optimally coordinate care for children with this complex problem.
A number of appointments are likely to be necessary to assess, discuss and plan management. It also may require appointments for further tests such as hearing and language tests or scans of the ear. As a general rule, implantable hearing solutions are considered from the age of 3 and a half whereas ear reconstruction is not possible until children are older (usually between 10 and 13).