The symptom of patients with microtia is that the auricle is completely undeveloped and there is no trace locally. This disease is extremely rare and the incidence rate is very low. At present, no special pathogenic factors of microtia have been found, and the cause is not very clear.

First, genetic factors.

Although practice has proved that a small number of patients with congenital microtia have family aggregation (there are many similar patients in the family), the probability of the next generation suffering from congenital microtia is much higher than that of the general population. Whether congenital microtia is passed on to the next generation, that is, the genetic factor of the disease, is also an important factor that parents of patients pay attention to. However, although congenital microtia has some genetic factors, it is not the most critical factor.

Second, the drug factor.

Mother's treatment of threatened abortion, anti-cold or antibiotic drugs and taking retinoic acid drugs are also important factors leading to congenital microtia.

Third, infection factors.

Pregnant mothers have a history of infection in early pregnancy, such as colds, respiratory and digestive diseases, which sometimes lead to congenital microtia of the fetus.

Fourth, the pollution factor.

Pregnant mothers have been exposed to toxic chemical corrosive agents or radiation for a long time during pregnancy, some have been engaged in fur products for a long time, and they have been exposed to computers for a long time without paying attention, which will cause health pollution and bring the risk of congenital microtia to the fetus.

Although the cause of microtia is not very clear, parents need not worry. By treating microtia, it can be completely cured without any serious influence.

Second, what are the hearing problems of microtia?

Parents are most concerned about hearing problems of microtia when consulting. They either think that the affected side has no hearing at all, or that hearing can be restored after drilling, or even that there will be an ear canal as long as the skin is cut. In fact, they all made conceptual mistakes, which have to be explained from embryonic development.

The ear consists of three parts: the outer ear, the middle ear and the inner ear. The external ear consists of auricle and external auditory canal; The inner ear is composed of snail cochlea, which acts like an electronic system, transmitting information to the brain through auditory nerve to form hearing; The middle ear is an air-containing cavity between the two, and there are three ossicles, namely the malleus, the incus and the stapes, forming a movable ossicular chain. During embryonic development, the outer ear and middle ear originated from the same tissue block, mainly the first and second branchial arches; However, the inner ear is another unique tissue origin.

Therefore, the middle ear of patients with microtia is deformed at the same time, while the inner ear is normal, so patients with microtia also have certain hearing (bone conduction hearing). The key to the problem is air conduction, because of atresia of external auditory canal and middle ear malformation, the hearing threshold of the affected side of the patient is 40-60 dB (normal 0-20 dB).

Fortunately, most patients with microtia have a normal ear on the healthy side, and the affected ear itself has a certain hearing, so apart from auditory localization, it has little impact on daily life and study. To correct hearing problems through surgery, it is necessary to avoid facial nerve and make a hole in the bone. Tissue transplantation will form tympanic membrane, but the deformed and fused ossicles may not be repaired.

There are also many problems in bone tunnel skin grafting, and as a result, chronic bleeding often occurs, followed by infection and unpleasant smell, and the opened bone hole (external auditory canal) often narrows. Even in the absence of complications, hearing has improved in the near future, and its long-term effect is difficult to last.

In addition, patients should avoid water in the ear canal and swimming after operation. In view of the technical limitations and healing problems mentioned above, most doctors in the world believe that the effect of middle ear surgery cannot offset the postoperative risks and complications, so it is only used for patients with bilateral microtia. Some doctors even think that if you can't handle patients with unilateral microtia well, don't do both. If hearing surgery is needed for bilateral microtia, it is generally believed that ear reconstruction should be done first, because hearing surgery will destroy the skin and form scars, and it is difficult to reconstruct the external ear in the future.