Craniofacial short deformity plastic surgery repair treatment – traction extension osteogenesis: a side of the craniomaxillofacial bone tissue and soft tissue congenital dysplasia, short deformity of the disease, clinically known as: craniofacial dwarfism or hemifacial dwarfism. It is caused by the obstruction of the development of the first and second gill arches of the fetus in utero. It causes craniofacial asymmetry on both sides. The degree of deformity may be mild or severe. Clinical manifestations] The main manifestations are short mandible and maxilla, small ear deformity, and in severe cases, it also affects the adjacent zygomatic bone, pterygoid pterygoid, temporal bone, as well as the expression muscle, masticatory muscle or subcutaneous tissues, and even orbital ectopia, microphthalmia, and orbital and facial clefts. It may also be accompanied by neurological abnormalities, most commonly facial nerve palsy. Mandibular anomalies: the main ones are hypoplastic mandible, short or completely absent ascending mandibular branch, and upward displacement of the mandibular body, resulting in mandibular deviation to the affected side. The most important abnormality of the lower skull is in the condyle of the mandible, which can be divided into three categories according to the severity of the deformity: Category 1: slight dysgenesis; Category 2: small condyle and mandibular ascending ramus, flattening of the condylar joints, and disappearance of the temporomandibular joint fossa; and Category 3: complete disappearance of the mandibular ascending ramus, or very little left. Correction of this deformity requires surgery, and the timing of corrective surgery of the maxilla and mandible is usually performed after the patient’s jaw development is basically stabilized. Currently, mandibular osteotomy and lengthening surgery can have a good effect on maxillofacial asymmetry, and its advantage lies in the fact that it can be carried out at an early stage, when the patient is about 2-4 years old. In some patients, it can be performed as early as 1 year of age; the surgery is less traumatic; the mandible tends to grow and develop normally after the surgery due to physiological stimulation; and the maxilla will improve vertically and horizontally under the stimulation of opening and closing or occlusion. All these are favorable to the overall development of the patient’s craniomaxillofacial region and the restoration of the appearance and shape, as well as the patient’s psychological health. The basic method is to make osteotomy in the bone segment ready to be extended, and then place the mandibular retractor, adjusting the rod from the mouth, and start adjusting the mandibular lengthening one week after the operation, usually adjusting 1~2mm per day. the speed of adjusting and the total length are controlled by the plastic surgeon according to the actual situation of the individual. In addition, soft tissue weaknesses can be filled with autologous fat tissue grafting. In this way, the asymmetry of the jaw and face can be improved as a whole. Early correction stimulates the development of the mandible and adjacent bones and contributes to the psychological well-being of the child. Reconstruction of the outer ear can be done as early as 5-6 years of age, when the child’s outer ear is already close to adult size. Depending on the individual situation and the patient’s wishes, autologous rib cartilage or biomaterials can be used to implant an ear brace, and depending on the severity of the defect, either partial or full ear reconstruction can be performed. Of course, adult patients who have not had reconstructive ear surgery can also benefit from this treatment. [Distraction Osteogenesis] Craniomaxillofacial Distraction Osteogenesis is a technique in which two bone segments, which have retained their soft tissue attachment and blood supply after truncation, are fixed for a period of time with a retractor, and then gradually retracted at a certain speed, frequency, and direction, and new bone is formed in the interstices of the severed ends of the bone in the process, thus lengthening the skeleton. The American doctor McCarthy in 1992 for the first time used the retraction osteogenesis to lengthen the human mandible, and in 1994 further reported a group of 15 cases of patients with clinical experience, 15 cases of patients with 8 cases of unilateral craniofacial shortness, 1 case of bilateral craniofacial shortness, 6 cases of small jaw deformity due to Treacher-Collins syndrome and Nager syndrome due to micrognathia, aged 1.6 to 13.7 years. After osteotomy of the ascending mandible, the mandible was fixed with an external fixator and retracted at a rate of 0.5 mm each time, twice a day, to lengthen the mandible by 18-36 mm according to the preoperative design, with an average of 24.5 mm. After the retraction was completed, the mandible was fixed for another 8 weeks, and the fixator was taken off after the bone healing was shown on the X-ray. An appropriately sized occlusal pad was placed in the surgically created posterior space and adjusted by the orthodontist a few months later to reduce the volume of the occlusal pad and facilitate the downward growth of the maxillary alveolar process. Regular postoperative follow-up and orthodontics may also be performed. McCarthy advocated that children can be considered for surgical correction at the age of 2 years, and proposed the indications for distraction osteogenesis for mandibular shortness: ① moderate or severe deformity of the mandible. ② The deformity must be corrected by osteotomy followed by bone grafting. The deformity must be corrected by osteotomy followed by bone grafting. ③ Conventional surgical reconstruction through external incision is required. We have made technical improvements to the previous methods and used a small intraoral retractor to advance the start of the corrective surgery; only the bone cortex is cut during osteotomy to protect the periosteum and inferior alveolar neurovascularity; the surgery is generally performed by an intraoral approach, leaving no scars on the facial skin. There are several keys to distraction osteogenesis to lengthen the mandible: preoperative model surgery or surgical simulation is required to determine the cortical incision line, fixation screw position, direction of distraction and lengthening length. The screw position should avoid the root and the capsule, and the cortical osteotomy should protect the periosteum, inferior alveolar artery, and nerves. After bone healing, the gap between the posterior teeth caused by the surgery is filled with dental pads, and the thickness is gradually reduced to guide the growth of the maxilla and mandible, alveolar bone and teeth. [Technical characteristics] Drafting osteogenesis has been perfected through a large number of experimental studies and clinical applications, and is generally divided into four phases: ① Osteotomy: it is best to perform cortical osteotomy to avoid cutting off the medullary blood vessels and to protect the periosteum as much as possible. Some scholars have also suggested that one week after complete osteotomy, the blood supply has been re-established, only for the cortical osteotomy is not necessary for bone regeneration, osteotomy and distraction can also become bone. ② Delayed period: that is, the stage from osteotomy to the beginning of distraction, generally 7-14 days, similar to the early stage of fracture repair, to remove blood clots, remove inflammation, and establish the blood supply, at this time, the osteogenic activity has been quite active. ③Retracting period: the speed of retraction is very important, too slow and easy to lead to premature osteogenesis and fusion, too fast is the formation of fibrous tissue in the retraction gap, resulting in bone non-connection. It is generally believed that the rate of distraction is 0.5~1.5mm per day, which is basically consistent with the synthesis of bone matrix. ④Fixation period: from the completion of distraction to the release of the distractor. During this period, the new bone is further formed, matured and remodeled, and obtains sufficient strength. This period usually lasts 6 to 8 weeks. Improvements in technique have avoided many complications such as infection, necrosis, and bone nonunion. With osteotomy followed by bone grafting, the recurrence rate is as high as 40% to 64%, whereas distraction osteogenesis has very few recurrences and retraction is about 7%. A small intraoral distraction fixator is used to avoid skin scarring. In conclusion, the operation of retraction osteogenesis is simple and safe, the effect is stable and reliable, no need for bone grafting, small injury, easy to control, the family soon learns to adjust the retractor after the operation, the hospitalization time is short, no need for intermandibular ligation and fixation, and it provides a new method for the correction and treatment of hemifacial shortness of mandibular hypoplasia, and underdevelopment of the middle part of the face. In recent years, medical device companies in the United States and Germany have produced three-dimensional retractors and intraoral retractors, and their use has reduced the occurrence of complications. With the advancement of craniofacial plastic surgery technology, distraction lengthening osteogenesis has been extended to the corrective treatment of midface and craniosynostosis.