What Is Microtia?
Microtia is a congenital condition of the ears that occurs during a child’s development in the womb and results in one or both ears being abnormally small, malformed or absent. Malformed ear canals are also a feature of microtia.
A relatively small number of children are affected by this condition. Of those, the majority experience microtia on one side of their head. Few children experience microtia on both sides of the head. The right side of the head is the most common side for the occurrence of microtia.
Although microtia primarily affects the pinna, or outer ear, of a child, it can also be accompanied by aural atresia or stenosis. Aural atresia is the closing of the ear canal, while aural stenosis refers to its narrowing.
Microtia often occurs on its own, though it can also occur as part of syndromes such as hemifacial macrosomia, Goldenhar syndrome and Treacher Collins syndrome. Other common disorders that accompany these syndromes can affect the eyes, kidneys, heart and bones.
What Causes Microtia?
The causes of microtia are still being studied, and doctors and scientists have not defined specific causes for this congenital ear defect. However, some believe that a decreased blood supply to the child’s ear during development in the womb is a cause.
The use of certain medications by the child’s mother during pregnancy have also been suggested as possible causes. Using medications such as Accutane, thalidomide and retinoic acid in the first trimester of a pregnancy may play a role in the development of microtia.
Doctors are still unsure of the role genetics plays in the development of microtia, though it does not appear to be a genetic order. While microtia may be able to be passed on as a gene in a family, it does not arise as a malfunction of a person’s genetic process.
What Are the Symptoms of Microtia?
Most children born with microtia also suffer from aural atresia or aural stenosis. Depending on the severity, this can cause a child to have either lessened hearing or deafness in the ear. These conditions of the ear canal and its inner components can occur without microtia.
The most noticeable symptom of microtia is a malformed or absent outer ear. In mild cases, the ear may not appear malformed at first glance. In severe cases, the ear may appear only as a small piece of skin or be completely absent.
Doctors base the severity of microtia on four grades:
- Grade I: The ear appears normal, however reduced in size. The ear canal is present, but is also reduced in size.
- Grade 2: The outer ear is partially formed, and the ear canal will be very small, narrow or closed.
- Grade 3: The external ear is mostly or completely absent along with the ear canal and eardrum. A small peanut-shaped structure of skin and cartilage may be present in place of the ear.
- Grade 4: The ear and its internal structures are completely absent.
What Are the Treatments for Microtia?
The goal of any treatment plan is to restore form and function to a child’s underdeveloped ear. Pediatric reconstructive plastic surgery can help in many cases to both create a more normal look while opening the child’s ear canal.
For children who do have surgery to correct microtia, the two predominate techniques used by craniofacial surgeons are the rib graft and MEDPOR® techniques. Because microtia alone rarely causes medical complications outside of possible hearing difficulties, in some cases parents and children may choose to forego surgery entirely.