The inferior alveolar nerve mainly controls the sensation of skin near mandibular teeth and lower lip. Because the nerve passes through the mandible near the incision during sagittal split of mandible, it may be damaged by vibration and traction during the operation, or it may be injured when fixing the bone block. After the injury, the feeling of the skin near the lower lip will become insensitive, and the probability of occurrence is about one in ten. About 90% patients will gradually improve and recover after three or four months, but a few people may not recover completely, and the lower lip will continue to feel insensitive. However, it does not affect daily life, and the movements of various parts of the face are not affected, and there will be no situation in which the corners of the mouth are skewed and drooling.

Postoperative bleeding and hematoma

Because the periosteum in the operation area needs to be peeled off, there may be blood clots and swelling, which is called hematoma in medicine. The probability of it happening is about 20 to 30%. Most hematomas are mild and will be absorbed by themselves. Only in rare cases, the amount of hematoma will be very large, indicating that there is the possibility of continuous bleeding at the surgical site. At this time, we need to go to the operating room urgently to stop bleeding.

Postoperative infection

All operations have the chance of infection. Because the incision of orthognathic surgery is mostly in the oral cavity, poor oral hygiene and abnormal life and rest after operation will increase the chance of infection. Overall, the probability of infection is about 3%. The treatment of postoperative infection, most of them only need outpatient follow-up and antibiotic treatment. In some cases, it may be necessary to open the wound slightly during outpatient service to drain the infection and help recovery. Only a few people need hospitalization, antibiotics or debridement.

Skin abrasion of corners of mouth

Because the operation is in the mouth, all the instruments should be put in the mouth. For the skin near the mouth and lips, especially the corners of the mouth, there is probably more than 50% chance of causing some superficial skin abrasions, which will heal themselves in one to two weeks and generally will not leave scars.

Psychological problems after changing face

After orthognathic surgery, there will be obvious changes in the five senses. Although the result of the operation will make the face proportion normal, some people will have self-identity problems. Friends, relatives and colleagues around you may not know you because of your different faces. If they agree with the features of your face before the operation and have some unintentional negative comments after the operation, it will cause psychological stress and adaptation problems.