Ear Reconstruction

Microtia

Microtia refers to an absence or underdevelopment of the external ear with or without development of an ear canal (Aural Atresia). Both of these conditions can occur by themselves in otherwise healthy children, or as part of a syndrome (e.g. Treacher-Collins or Goldenhar's syndrome). Microtia and aural atresia can affect one ear or both and can be associated with normal or abnormal inner ears. In many cases, children with microtia and/or aural atresia have normal inner ears and subsequently have normal "nerve" hearing levels. However, if children do not have an external ear and patent ear canal, then sound is physically blocked from reaching the inner ear and the child demonstrates what's called a "conductive" hearing loss. To further complicate matters, children with microtia, and to a lesser extent aural atresia, are faced with difficult social problems due to their different appearance as well as difficulty hearing. The CHDR has established a program to provide comprehensive care for children with these complex medical problems. Our management philosophy centers first on restoration of functional hearing whenever possible and then on aesthetic reconstruction of the ear so that a child's self-esteem and confidence are improved to allow normal social interaction and maturation.

Microtia includes a variety of outer ear developmental defects - ranging from mildly underdeveloped ears to complete failure to form any sort of ear structure. The degree of hearing loss and other developmental defects often coincides with how severe the outer ear malformation is. The better developed the outer ear, the better developed the middle and inner ears usually are. Being a fairly obvious congenital problem in most cases, microtia is typically detected at birth and the child referred for an initial evaluation by an ear specialist. Our primary concern is functional hearing in children. Therefore, a hearing test is usually performed early on in the process. In cases of unilateral microtia (one ear affected), the unaffected ear commonly has normal hearing. However, it is necessary to confirm that the child has at least one normal hearing ear so that the child can remain on track for normal communication skills development. If both ears are affected (bilateral microtia), then earlier intervention is indicated so that the child is given the chance to develop hearing and speech. CT scans of the ear region are obtained after the 1st year of life in order to determine whether the inner and middle ear structures have formed properly. (Although scans can be obtained at any time, since no interventions would be recommended so early in infancy, no reason exist to obtain a scan earlier than 1 year of age). If the scans show a normal inner and middle ear, and hearing tests confirm normal nerve hearing levels, then the child is typically considered a good candidate for a hearing restoration type procedure. This would typically involve creation of an outer ear, ear canal and eardrum. However, this typically involves a lengthy 4 stage procedure in the case of a permanent autologous reconstruction, or 2-3 staged procedures with a prosthetic reconstruction. Several considerations need to be weighed in deciding which options are best for any given child and their family. Below are discussed the two reconstruction options offered at the CHDR along with the relative advantages and disadvantages. It should be noted that both surgical options are normally delayed until the child reaches 5-6 years of age. The rationale for waiting is that a child's outer ear is adult size by the time the child reaches this age range. Since a reconstructed ear does not grow like a normal ear has to be modeled upon the opposite ear for a symmetric appearance, performing the surgery any earlier would result in an asymmetric appearance. Waiting any later tends to cause more social problems as children enter elementary school at an age where other children are more observant of physical differences.

Autologous Reconstruction

With autologous reconstruction, a new ear is constructed by using cartilage and tissue borrowed from other sites of the body. In the 1st stage, rib cartilage is harvested, shaped into a framework for the new ear using the opposite (normal) ear as a template or model. This cartilage is then buried under the skin where the new ear will be reconstructed. Each stage is planned several months later (anywhere from 3-5 months) to allow the child to recover completely and to let the transplanted tissue establish its own blood supply for survival. At the 2nd stage, the developed ear lobe is transposed to a more natural position in line with the contour of the cartilage framework. At a 3rd stage, the transplanted cartilage is elevated off the side of the head so that it protrudes at an angle similar to the opposite ear. A free skin graft is necessary to line the back side of the ear framework and can be harvested from a concealed area such as the hip, upper thigh or upper inner arm. Finally, the 4th stage involves creation of an ear canal and eardrum in an attempt to restore hearing to the ear. Again a skin graft is required to line the newly created ear canal and eardrum to promote rapid healing without excess scarring. Overall, the process typically takes ~1 year from beginning to end with most procedures being either an overnight admission to the hospital or outpatient surgery. The end results of such a process are variable and largely depend upon the original degree of development (or maldevelopment) of the ear. In terms of hearing, a child's final hearing result is largely determined by the size and development of the middle ear space and the three ossicle (bones) that normally vibrate and transmit sound to the inner ear. In cases with poorly developed middle ears and ossicles, hearing tends to be improved but below normal hearing levels postoperatively. In children with well-developed middle ears and ossicles, the hearing results tend to be significantly better with some children attaining normal hearing thresholds. It is significant to consider that even if hearing restoration is not complete, with the creation of a patent ear canal and eardrum, it is now an option to insert a hearing aide which can help compensate for any residual hearing loss. The cosmetic appearance of the outer ear is also somewhat variable and is in part determined by the individual's healing process. A reasonable expectation from this procedure is to have an ear that on direct frontal view does not draw any attention (even with short hair cuts) and that the child is comfortable with in interacting with friends. Most patients will have an ear that is recognizably different on close examination. However, it should not be the first feature that draws your attention when seeing the child in daily life. A major disadvantages of this method of reconstruction is the number of procedures that have to be performed and the fact that rib cartilage and skin grafts are needed and may cause minor scarring at the donor sites. The advantages are that it provides a very reasonable and acceptable cosmetic and functional result that is permanent and doesn't require "maintenance" as prosthetic ears need on a daily basis.

Prosthetic Reconstruction

With prosthetic reconstruction, an artificial ear is fabricated by the CHDR's prosthetic surgeon, Gordon Huntress, D.M.D. Depending upon the status of the middle and inner ears, this prosthetic outer ear reconstruction can be combined with creation of an ear canal and eardrum, or performed alone to provide an improved appearance for the child. In order to provide a stable attachment of the prosthetic ear, permanent titanium implants (hollow screws) are surgically placed into the bone underlying the ear region. Once these implants are incorporated into the bone (called "osteointegration" and usually requiring 6-8 months), small posts are inserted that protrude through the skin and allow attachment of the prosthetic ear either by clips or magnets to these posts.