Microtia is a relatively common birth defect in which the outer ear, also known as the pinna or auricle, is unusually small or misshapen. When the outer ear is missing altogether the disorder is known as anotia. While substantially more common as a unilateral condition, microtia may occur in one or both ears. Children with microtia are not only at risk of developing psychological problems because of their abnormal appearance, but are also likely to suffer from hearing loss to a lesser or greater degree. Since hearing loss will adversely affect the development of speech and language skills, surgery at an early age is usually recommended to treat this condition.
Types of Microtia
Microtia is usually categorized in gradations of severity determined both by the extent of the deformity of the outer ear and the effect of the abnormality on the hearing process.
When a patient has grade I microtia, the ear is slightly smaller than normal but is structured normally. The ear canal, though abnormally small, is present.
A patient with a partially missing ear is considered to have grade II microtia. With grade II microtia, the external ear canal is stenotic, or narrowed to point of blockage, so that the patient experiences a conductive hearing loss.
With grade III microtia, the patient has only a small vestigial remnant of the external ear and has extensive conductive hearing loss due to an absence of the external ear canal and ear drum. Sometimes this condition also involves a fusion of the ossicles, the small bones of the inner ear.
A patient born without any ear has the most severe type of microtia which is known as anotia.
Microtia and Hearing Loss
Many, or even most, children with microtia also have a disorder involving an underdevelopment of the ear canals and other structures of the middle ear. This condition, known as aural atresia, results in conductive hearing impairment. Most commonly, patients with microtia, have approximately a 40 percent loss of hearing. In some cases, patients with microtia suffer from sensorineural, of nerve-centered, hearing loss as well conductive impairment.
Microtia Repair Procedures and Treatments
Fortunately, there are surgical procedures to correct both the appearance of the outer ear and to improve hearing function. Most of the time, these surgeries are performed in early childhood, although adults can undergo this reconstruction as well. In most cases, several operations will be necessary due to the complexities of performing both cosmetic and functional, corrections and due to the fact that the outer, middle, and often inner, ear may all require repair.
Reconstruction may be performed using the patient's own tissue or, on occasion, by implanting a plastic prothesis. If the patient's own tissue is used, there will be a series of procedures that may involve repositioning existing ear elements, harvesting cartilage from other areas of the body and using skin grafts to create a normal-looking ear. This cartilage is molded and placed under the skin on the affected side of the scalp. These surgical procedures are complex and are usually performed in stages. When a prosthetic device is implanted, a specialist will craft it carefully to match the patient's other ear.Where the patient is experiencing sensorineural hearing loss, usually as a result of a cochlear abnormality, ear surgery is not the solution. In such a situation, hearing aids may be helpful. There is also the possibility that the patient will benefit from a cochlear implant. Many doctors believe that surgery is not necessary for the lesser grades of microtia and that hearing aids are a better choice. Patients with hearing loss from microtia, whether they undergo surgery or not, will usually benefit greatly from speech therapy.