Saw off the chin joint, pull out the first incisor on the affected side, and cut off the chin joint with a wire saw. 5. Cut off the connection between coracoid process and condyle: Pull the sawed mandible outward, cut off the muscles and mucosa lining the lingual floor of mandible, then cut off the attachment of medial pterygoid muscle and temporal muscle, ligate and cut off the inferior alveolar nerve and blood vessels, finally cut off the attachment of articular capsule and lateral pterygoid muscle around condyle, and then cut off one side of mandible. 6. Suture the oral mucosa: sew the incisal edge of the oral mucosa and buccal mucosa tightly, and use 1-2 layer for submucosal reinforcement suture. 7. Immediate bone grafting: Take a rib with proper length and curvature, with cartilage at the end. Immediate transplantation of mandibular defect. One end with cartilage is placed in the magnetic recess of the temporal bone. 1 multiple cortical bones were removed from the side of healthy mandible, so that the ribs with the same cortical bones were anastomosed with them. After drilling, fix it with thin steel wire to make it heal. 8. Suture: This is the last step of the operation. After stopping bleeding, the doctor washed the wound with normal saline, placed a rubber drainage strip or negative pressure suction tube, and sewed it layer by layer.