This is a congenital developmental facial malformation, which is characterized by multiple structural dysplasia on one side of the face, hence the name “syndrome”, also known medically as first and second gill arch syndrome, mouth-mandibular-ear syndrome, and ear-mandibular dysplasia. The pathogenesis is unclear. It mainly involves soft and hard tissue deformities of the face due to abnormal development of the first and second gill arches. The most important manifestation is the short growth of the lower part of one side of the face, the face is large on one side and small on the other, and it is obviously skewed. If you look closely, you will find the poor development of ear, mandible, maxilla, zygoma, muscle and other soft tissues. 1. Skeletal deformity: One side of the mandible is poorly developed, manifesting as a small, skewed chin, and in severe cases, there may be a defect in the ascending branch of the mandible and a defect in the condyle. Some zygomatic and maxillary bones exhibit dysplasia, shortening, and delayed eruption of molar teeth with shortened vertical height. The upper and lower dentition is also skewed, with the healthy side low and the affected side high. 2.Muscle deformity: One side has poor muscle development, including expression muscle and masticatory muscle, sometimes the performance is not obvious, but only shows local depression. 3. External ear deformity: In mild cases, the deformity may appear as shell-shaped ears or curly ears; in severe cases, the deformity may appear as small ears or no ears, often accompanied by hearing impairment. Many congenital microtia are actually manifestations of various degrees of craniofacial shortening deformities, often synchronized with the degree of mandibular dysplasia. 4. Other soft tissue malformations: Most of the moderate and severe craniofacial microtia are accompanied by partial or complete facial nerve hypoplasia, which can be the buccal branch or the mandibular rim branch, and can also involve the ophthalmic branch or the frontal branch. Sometimes there is also transverse facial cleft or corners of the mouth redundancy. In addition to congenital developmental causes, there are also similar dysmorphic changes that occur in childhood when one side of the face is treated with radiation or isotope therapy due to hemangioma or vascular malformation. Another disease that causes similar changes is progressive facial atrophy, which occurs especially in childhood and is often so severe that the skin, subcutaneous tissue, muscles, glands, and bones all atrophy, like a layer of skin wrapped around shrunken bones. This deformity can only be treated by surgery. It is divided into early and adult treatment, and it should be treated early. Doing early treatment after the age of 6 can stop the development of more serious deformities. So once this condition is detected, it is important to be seen early. A number of doctors recommend waiting until adulthood (after the age of 17) to do the surgery, which is inappropriate. The need for multiple surgeries is a feature of the treatment of this disease. Performing the right surgery at the right time is the key to getting the best treatment results. The most appropriate time and treatment methods are: from 6 to 9 years of age, a simple mandibular traction osteogenesis followed by orthodontics to correct the inclined occlusal plane, and after 6 years of age, auricular reconstruction, usually using autologous rib cartilage for the auricular scaffold. After the age of 9 years old and into adulthood, the maxilla and mandible can be osteotomized and traction lengthened at the same time to achieve a balance between the upper and lower jaws in the upward and downward directions. There is no definite cut-off time for bony and soft tissue augmentation surgery, which is usually considered at an older age. Prof. Liou generally chooses to do this type of surgery after the age of 13 years, including bone augmentation with materials, fat injection filling, and dermal fat tissue grafting. If a patient is seen late or is already an adult and has significant asymmetry in the skewing of both sides of the face, in addition to surgery on the affected side, the bones on the healthy side may have to be cut appropriately to make both sides of the face more easily balanced and symmetrical.