Microtia & Ear Deformities
Congenital ear deformities occur in many different syndromes or alone. The term microtia indicates a small, abnormally shaped or absent external ear. It can occur on one side only (called “unilateral”) or on both sides (called “bilateral”). The unilateral form is much more common, occurring in approximately 90% of patients. Unilateral Microtia occurs in 1 out of 8,000 births and Bilateral Microtia occurs in 1 out of 25,000 births.
Repair of congenital microtia requires the coordinated efforts of both facial plastic surgeon and ear surgeon. Reconstruction of the microtic ear is usually delayed until the child is 6-10 years old. At that age, cartilage from the rib is used to reconstruct the external ear. Several operations may be necessary. The ear surgeon will usually delay reconstruction of the external auditory canal, (i.e. correction of the atresia), until the initial phases of the microtia repair are completed.
Microtia does not always occur along with atresia. Isolated atresia can occur in an ear which appears normal. Microtia repair falls under the province of the facial plastic surgeon, so a complete explanation of this surgery will not be offered here. Microtia is a most obvious abnormality. Any child with microtia should be seen early by an ear surgeon in order to coordinate the procedure between the facial plastic surgeon and ear surgeon. In addition, testing for hearing in both ears is indicated early, using Brain Stem Evoked Response Audiometry. This testing must be done early to determine the adequacy of hearing in the “normal” ear, as well as to confirm whether it is really normal.
Surgical Techniques
Surgical correction over the last twenty ears has been dominated by a technique by Dr. Burt Brent from California. This technique is based on a four-stage procedure that is started at 5-6 years of age. Newer techniques based on the designs of Dr. Satoru Nagata in Japan require 2 separate procedures, six months apart beginning when the patient is between 8-10 years of age. There is substantial evidence that delaying surgery until 8-10 years of age will produce results which are more stable and the definition is superior.
This procedure requires cartilage from the ribs that allows a very detailed reconstruction of the new framework that includes all parts of the ear, including the tragus and the lobule. The second stage, six months later, involves the elevation of the cartilage and skin framework to achieve the projection required. Within a six-month period and subsequent healing, the entire ear, framework and projection is complete.
Additionally, many patients with microtia also have aural atresia and may be candidates for atresiapalty or inner ear reconstruction. This is performed by a specially trained surgeon called a neuro-otologist. These procedures are generally performed after the microtia reconstruction is complete so as to place the canal in the correct position and so it will not damage the delicate flaps for the ear reconstruction. Prior to this is bi aural hearing is desired, a bone anchored hearing aid (BAHA) can be placed. This procedure is somewhat controversial in patients that have unilateral hearing and should be discussed with the ear reconstruction team.
Treatment Team
The Microtia/Aural Atresia team is comprised of the following specialists:
- Craniofacial/plastic surgeon
- Neuro Otologist
- Audiologist
- Speech Therapist
- Social Work
- Photography
Patient Evaluation
Patient evaluations usually begin early in life, sometime in the first 3 months as the families usually have many questions and are nervous about the deformity. Annual follow-ups are necessary until the time for surgery is met. Often, the Neuro-otologist will be the first to operate by placing the BAHA. Computer tomography scans are required at different intervals to evaluate the internal anatomy of the ear and may be repeated on a regular basis to evaluate growth. If other anomalies are present, different radiographic interventions may be necessary as well as surgery.
