Wound lengthening is derived from debridement, which is a common surgical procedure that removes foreign bodies, dirt, and necrotic tissues from the wound, especially when there is severe contamination that will lead to non-healing of the wound and secondary infection. When the wound needs to be extended, the wound is further exposed on the basis of debridement, and the wound can be extended, the significance of the extension is mainly to make the debridement more thorough, and facilitate the cleaning and disinfection of the wound. If necessary, a drain should be placed. If there is a serious foreign body or tissue infection or the wound is already red, swollen, red and has a lot of exudate, it is impossible to close the wound after the extension, and a drain can only be placed and a second-stage suture can be placed.