Microtia (Ear Reconstruction)
What is Microtia?
Microtia is present when a baby is born with one or both ears that are smaller than normal. The ear is usually so abnormally shaped and small that it no longer looks like an ear, and it is occasionally completely absent (anotia). The ear canal and ear drum are also commonly absent, a condition called aural atresia. In 80-90% of cases microtia is present on only one side and the other ear is of normal dimensions. The mildest form of microtia is when the ear appears smaller than usual but still has most of the features that a normal ear has. The most common scenario is one where the cartilage part of the ear is very small and abnormally shaped and the ear lobe is present, but rotated forward and upward giving it an abnormal appearance. In this most common scenario, the ear canal is also absent or very narrowed. When the ear canal is absent it is called aural atresia. If aural atresia is present the child should be evaluated by an Ears, Nose and Throat (ENT) specialist to determine what the effects on hearing are and what if anything should be done to improve hearing. There are several grading systems used to describe how severe the microtia is. Below are examples of the different grades of microtia.
It is important to note that microtia is most often associated with a condition called hemifacial microsomia (craniofacial microsomia). This condition is present when there are abnormally small facial features present on one or both sides of the face, including the ear, lower jaw and bulk of the cheek. Craniofacial microsomia is believed to be due to an abnormal circulation of blood to the face during development which leads to decreased growth of the skin, fat and bone of the face and often microtia.
More rare conditions are also associated with microtia. These include Goldenhaar syndrome and Treacher Collins syndrome. These patients can have multiple issues in addition to craniofacial microsomia and microtia and should be treated in a special way for these reasons.
HOW IS MICROTIA DIFFERENT FROM OTHER MISSHAPEN EARS?
Differences in the shape, size and position of any of the key features of the ear can cause the ear to look abnormal and draw unwanted attention. Unfortunately for children, this is often accompanied by teasing from peers and the development of self-esteem issues that may be carried on into adulthood. Differences in the appearance of the ear can be divided into two main categories. The first category of congenital ear anomalies includes ears with differences in the shape, size or position of the ear that are minor and can be corrected by reshaping the existing tissues of the ear with an otoplasty or more minor ear reconstruction. These more minor congenital ear anomalies include prominent ears, mild or moderate constricted ear, Stahl ear and Cryptotia. The second category of ear anomalies are those where the ear is severely underdeveloped resulting in differences in the shape and size of the ear that are severe and require creation of an entirely new ear. This group includes microtia and severe constricted or lop ear deformity. The remainder of this page will discuss ear reconstruction for creation of an entirely new ear. Please click on the appropriate links to see information on treatment of prominent ears, constricted ears, cryptotia and Stahl ear deformity that can be corrected by reshaping the ears.
When considering creation of a completely new ear it is helpful to understand what the normal features of the ear are.
Normal Ear Anatomy
Just like noses, eyes and lips, ears can look quite a bit different from one person to the next, but our minds will recognize almost all of them as normal. There are some key features that our minds look for when determining if an ear appears normal or not. Below are the key features of a normal ear.
Treatment of microtia
The external ear is mostly made up of skin and cartilage. The ear cartilage is fairly unique in the body. It bends very easily and returns to its exact shape. This special property helps the external ear avoid injury. The ear canal leads to the eardrum which transmits sounds to the inner ear that allows us to hear. It is possible to have a normal appearing external ear and not have a canal, and also possible to be missing the external ear and have an open canal and normal hearing. However, most often people with microtia have some abnormality of the canal and possibly the inner ear.
There are three main approaches to reconstruction of the external ear for treatment of microtia, each is discussed in detail on their respective pages. The two most popular methods involve burying a framework under the skin to create a new ear which will be a permanent part of the patient. The first method uses an implant made from Porous Polythylene (Medpor) to create a normal appearing ear. The second, which is the oldest type of reconstruction, uses rib cartilage harvested from the chest that is carved and assembled into a framework with a shape similar to the Medpor framework. The third method which is not part of the patient, is to use a prosthetic ear that is anchored to implants in the bone. This prosthesis can be removed.
Porous polyethylene (Medpor) Ear Reconstruction
The key concept of ear reconstruction is that a scaffold must be placed under the skin in the normal ear position to create a contour that looks like a normal ear. The implant approach relies on a Medpor implant (porous polyethylene) to provide the shape and projection of the ear. The pore structure of the Medpor allows for growth of the patient’s tissue into the implant. Using the Medpor implant removes the need for surgery in the chest to harvest of rib cartilage. Thus there is no pain, scarring or deformity of the chest with this approach. The Medpor implant is made up of two pieces that are custom assembled to provide the new ear with a similar size and shape and details of a normal ear.
The pores of the Medpor implant allow the patient’s tissues to grow into the implant. While the implant not living tissue, this tissue ingrowth helps provide resilience to infection. The implant is covered with a thin layer of tissue from the scalp and skin from the ears. This thin tissue allows for the delicate features of the ear to be created. The skin on the front of the ear is ear skin from around the microtic ear and from the back of the unaffected ear. The color match of the skin covering the back of the ear is less important cosmetically, therefore harvesting from the groin crease is preferred because it leaves the donor scar that is hidden in the under wear line. In our experience, the average ear reconstruction from the Medpor approach looks like a normal ear after a single surgery and alleviates unwanted attention.
ADVANTAGES OF MEDPOR EAR RECONSTRUCTION
The Medpor technique can be done at a much earlier age than the rib cartilage approach because we don’t have to wait for the rib cartilage to grow. As surgeons have gained more experience with rib cartilage ear reconstruction they pushed the age of surgery back farther and farther to allow the children to grow more before performing surgery to get enough cartilage to make the ear. Now surgeons typically wait until age 10-12 years old for rib cartilage ear reconstruction. There are undoubtedly significant self-image, self-esteem and psychocial issues related to the appearance of the ear by this age. This is the primary reason why we prefer the implant based approach to ear reconstruction. We usually perform Medpor ear reconstruction from age 5 years old and up. While patients are aware that their ear appears different by age 5, it is rare that patients have been teased or will have long-lasting psychosocial issues related to the appearance of the ear if reconstruction is performed at this age. Using the Medpor ear reconstruction approach allows the whole reconstruction process to be completed before any issues with self-esteem or teasing arise.
In addition to earlier completion of reconstruction, use of the implant avoids the need to borrow cartilage from the ribcage. This removes the scarring, pain and chest deformity associated with the harvest of the rib cartilage. The use of the tissue from the scalp and small skin grafts to completely cover the ear at the first surgery also allows the typical Medpor reconstruction to be completed in fewer surgeries than the average rib cartilage approach. Usually there is a well projected ear with normal features including positioning of the earlobe after one surgery.
The Medpor approach can easily be integrated with an atresia reconstruction or BAHA placement to improve hearing. Careful coordination between the Ears, Nose and Throat surgeon and plastic surgeon is needed to make sure that the best possible result in both hearing and the appearance of the ear is achieved.
Rib Cartilage Ear Reconstruction
This approach is the oldest and most widely performed technique for ear reconstruction. It has been used for well over 50 years. This approach is usually performed at around10 years of age. The general idea is to harvest the strong cartilage from the rib cage, carve this cartilage and assemble it into a framework using wires or suture material to create a construct with the normal features of the ear. The framework is placed under a skin pocket in the location of the microtia to create a new external ear.
This approach uses the child’s own tissue (cartilage) to create the new ear which is appealing to many patients. The cartilage is strong and resistant to breaking. It is the patient's own tissue that is fully integrated into the new location. These are all positive attributes. There are a couple of downsides to this approach as well. To harvest the cartilage an incision must be made in the chest and the removal of cartilage from several ribs is needed. This places a scar on the chest and can cause an irregular shape to the chest on the side of surgery. In order to get enough cartilage to make an ear of normal size, we must wait until the child is about age 10 years old. This is an age when teasing from peers and self-esteem issues are already present. A picture of a typical cartilage construct and finished construction is shown below.
The primary disadvantage of rib based ear reconstruction is that there is not enough skin in the location of the microtia to allow for the ear framework to be covered on its front and back sides at the same time. Therefore, the framework is put under the skin and lies flat against the head. This must be allowed to heal for a period of time to allow the skin to become adherent to the cartilage. The ear is then elevated in a second surgery to try to project the ear forward sufficiently to match the normal side. Other components of the ear reconstruction are also performed in stages. The rib cartilage approach usually takes 2-4 surgeries with the classic approaches.
We do not favor this approach for most patients. Perhaps the most significant issue with the rib cartilage approach is that it is usually performed at an average age of 10 years of age, an age at most children will already have significant self esteem issues and problems with teasing by peers. Our other concerns are related to the deformity and pain in the chest donor site, the number of surgeries required and the quality of the average result. While some surgeons, with many years of experience, can provide reliably good results with the rib cartilage approach, in our experience the results obtained with rib cartilage can be quite variable. We believe that the goals of ear reconstruction should be to have the average result obtained look like an ear. In our experience the average result of an ear reconstruction from rib cartilage does not look like a normal ear and still draws unwanted attention.