Progressive hemifacial arophy is an acquired facial deformity characterized by progressive unilateral atrophy of the skin, subcutaneous tissue and bone structures. The lesion mainly involves the hemifacial tissues, and in mild cases it leads to sunken cheeks and bilateral facial asymmetry. In severe cases, the upper and lower jaws are underdeveloped, the eyes are sunken, and the vision is diminished or blinded, resulting in serious disfigurement of the face. According to the severity of hemifacial atrophy, hemifacial atrophy deformity is classified as mild, moderate or severe. 1. Mild Local soft tissue atrophy of the affected cheek, the overall facial contour is basically symmetrical, the nose and lips are not obviously involved, and there is no obvious angle of mouth tilt. 2.Moderate Facial soft tissue atrophy, forming a clear demarcation with the healthy side, nasal wing atrophy, upper lip atrophy on the affected side, mouth angle skewing to the affected side, facial bone involvement. 3.Severe Facial soft tissue atrophy, deep bone dysplasia, with chin deviation and jaw plane tilt. Treatment principles Bilateral asymmetrical deformities of the craniomaxillofacial region caused by hemifacial atrophy are a group of deformities that are common and difficult to treat clinically, with varying degrees of severity, involving the treatment of soft and bone tissues. The etiology and pathogenesis of this deformity are still unclear, and there is no effective treatment to stop or reduce the development of the deformity for patients in the progressive stage, and only surgical treatment can be used after the development of the disease has stopped. According to the patient’s specific situation, a personalized surgical plan should be reasonably designed, and the techniques of plastic surgery and craniomaxillofacial surgery should be used to reconstruct the deformity in stages. 1, the skeletal deformity is not obvious but mainly soft tissue atrophy depression, can be filled and repaired by means of tissue transplantation. 2.For patients with craniofacial skeletal dysplasia, the reconstruction of facial skeletal scaffold should be emphasized. 3. For patients with severe hemifacial atrophy and obvious soft tissue atrophy, the blood supply of local bone and soft tissue is poor, so soft tissue coverage should be solved first and bone reconstruction should be considered in stage II. Surgical methods Soft tissue reconstruction 1. Mild to moderate facial soft tissue atrophy and depression – use autologous fat particles to fill in by injection. 2. Localized depression of autologous fat particles cannot be filled by sub-injection – autologous dermal graft is used to fill. 3. Severe facial soft tissue atrophy – free tissue graft with anastomosis of blood vessels. Anterolateral fascial fat flap or scapular dermal fat flap can be used to fill the depressed face, and contouring will be performed after 3-6 months. Reconstruction of facial bones According to the degree of skeletal involvement, the following methods can be used to reconstruct 1, mild zygomatic and mandibular dysplasia with a normal occlusal relationship (1) bone grafting of the affected zygomatic bone and mandible to increase the anterior protrusion of the zygomatic bone and the width of the mandible. (2) chin osteotomy to correct the skewed chin deformity. (2) Maxillary and mandibular dysplasia with occlusal plane tilt (1) maxillary Le Fort I osteotomy rotation, mandibular sagittal split osteotomy rotation and chin osteotomy displacement (2) patients with severe occlusal plane tilt, simultaneous maxillary Le Fort I osteotomy and mandibular sagittal split osteotomy rotation to correct jaw plane skew is often difficult, such patients are best first mandibular ascending branch and body retraction lengthening surgery In such patients, it is better to perform mandibular ascending and body distraction lengthening first to correct the mandibular deformity, and then perform maxillary Le Fort I osteotomy in stage II to rotate down and correct the open jaw on the affected side. In conclusion, the treatment of severe hemifacial atrophy is still one of the most difficult problems in plastic surgery, mainly because of the difficulty of surgery, the number of operations and the unsatisfactory results. Atrophy of the nasal flank, the angular deviation of the mouth caused by the shortening of the upper lip, and the sunken eyes caused by the atrophy of the orbital contents are among the most difficult to treat.