Microtia is what we usually call auricular hypoplasia. In mild cases, the auricle is smaller than normal, while in severe cases, the auricle may be completely absent, with atresia of the external auditory canal and hypoplasia of the middle ear, but the inner ear development is mostly normal. Studies have shown that microtia is associated with viral infections in early pregnancy, medication, mental stimulation, or exposure to radiation or environmental pollution. These factors affect the development of the 1st and 2nd parotid arches of the fetus, resulting in congenital microtia. According to a survey, the incidence of this disease in China is as high as 4000:1. It should be noted that microtia is not a genetic cause. According to incomplete statistics, there is a 2.5% family prevalence rate in China, i.e. 2.5 out of 100 families have such patients. In typical microtia patients, the stump of the ear appears as a peanut-like mass that does not grow with age, so the only way to return a normal-sized ear to the child is through surgery. Some patients with microtia have normal hearing (which is less affected by atresia of the external ear canal), some have only residual hearing due to malformations of the middle ear, and about 2% have no hearing at all due to malformations of the middle and inner ear. Fortunately, most patients with microtia have one normal ear, plus the affected ear itself has partial hearing of 40-60 dB (normal 0-20 dB), so they are basically unaffected in their daily learning and life. Patients with bilateral microtia with external atresia should generally be considered for external and middle ear surgery first to improve their hearing. For patients with unilateral microtia with external atresia, if there is no hearing requirement, auricular reconstruction should be performed directly; for those who have hearing requirement, external ear canal and middle ear surgery should be performed first, followed by ossicular reconstruction at a later stage. Generally speaking, the auricle of 3-year-old children has already reached 85% of adult size physiologically, and has basically developed to adult size around the age of 6. Therefore, in order to reduce the psychological pressure and injury of children, theoretically 6 to 10 years old is a better age for auricle reconstruction surgery, but due to the requirements of the surgery on rib cartilage, blood vessels, fascia and skin, the best clinical age for auricle reconstruction is still in the teenage – when the body is more fully developed. There are many ways to reconstruct the auricle, which can be broadly divided into staged surgery and one-stage surgery. The materials used are divided into autologous materials (such as rib cartilage) and artificial materials (such as Medpor). Autologous rib cartilage is sculpted and combined to form the outer ear contour, forming the ear scaffold. The skin of the residual ear is reasonably transposed to preserve the earlobe, and finally the sculpted ear scaffold is buried under the skin behind the residual ear. After six months to a year, a second stage of surgery is performed to establish the ear and reconstruct the cranial angle of the ear. The advantages are that the reconstructed ear is realistic and well-defined, has blood supply and sensation, and can withstand normal pressure during sleep. The disadvantage is that the number of rib cartilage needed is high, at least two to three, and the patient suffers a lot of pain, with the possibility of complications such as pneumothorax and thoracic deformity, and must be operated in stages, so the patient has to suffer the pain of two operations. There is also the possibility of absorption and deformation of the transplanted rib cartilage, which can affect the shape. Medpor is a very high density porous polyethylene biomaterial with many interconnected pores, and the Medpor ear scaffold is highly stable and contains longitudinal and transverse pores that allow new tissue to grow in quickly and form a stable complex with the growing tissue. It has the advantages of good shape, realistic appearance, clear appearance of the auricular microstructure, and not easily deformed. The disadvantage is that there is a certain rate of tissue rejection, hard texture, poor elasticity, and the risk of exposure due to pressure or trauma, but this can be reduced by using local flaps and fascial flaps with blood vessels, which are slightly more expensive. To reduce complications, the ear can also be reconstructed using a MEDPOR ear base covered by a ring of autologous rib cartilage as the ear whorl, which provides better results.