Congenital microtia is a congenital dysplasia of the auricle, with an incidence of 6000:1 in Europe and the United States, 4000:1 in Japan, and about 4000:1 in China.
The average incidence of microtia is about 1:7000, with the right side being more common, about 60%, the left side being 33%, and the bilateral microtia being 7%.
The causes are generally thought to be abnormal events in early pregnancy, such as viral infections, medication, mental stimulation, or exposure to radiation and environmental pollution. Congenital microtia is caused by abnormal development of the first and second gill arches during the embryonic period. The auricle is severely hypoplastic, with no normal auricular landmarks, only contractures in the ear area, small malformed cartilage masses and ectopic earlobes. About 50% of microtia cases have significant associated deformities, such as hemifacial atrophy and hypoplasia of the upper and lower jaws and zygomatic bones. The typical patient with microtia has a stump ear shaped like a peanut that does not grow open with age. The auricular deficiency can seriously affect the normal psychological development of children. Children will go to school and cause ridicule from their peers, causing normal psychological development of children, and as adults, they often grow long hair to cover the defect and are ashamed to interact with normal people. Unilateral hearing loss makes the patient’s sense of direction diminished, and the patient often compensates by hearing sounds sideways. Bilateral microtia is often associated with a lack of hearing and extreme inconvenience in life. In order not to affect the physical and mental health of the child, surgery should be done before school age as much as possible, generally after the age of 6 weeks and before puberty (around 14 years old) is the best age for surgery. If the age is too young, the development of the autologous rib cartilage is small and the extraction of material is limited, but also due to changes in growth and development may cause changes in the shape of the reconstructed ear and deformity of the thorax; however, do not wait until you are too old to have the surgery, as the texture of the rib cartilage will also change with age, which will have an impact on the sculpting of the outer ear reconstruction scaffold and the maintenance of the later shape. Congenital microtia is often associated with auditory dysfunction. This is both a medical problem and a social problem. The resulting auricular deformity and hearing impairment seriously affect the physical and mental health of the affected child, and patients require not only a reconstructed auricle and external auditory canal with normal morphology, but also functional hearing. It is of great social importance to find ways to enable patients to be treated and reintegrated into a healthy life in society. Simultaneous total ear reconstruction and hearing reconstruction is an extremely challenging problem.