Mandibular angle osteotomy can be divided into two methods: intraoral incision and extraoral incision. Intraoral incision has certain risks, which usually occurs under anesthesia. The extraoral incision is safer. What my friend did in Weifang Boya was extraoral incision, and the effect was very good. It takes a long time to make an incision from the outside, and you can't tell it without looking carefully.