Flaps do not usually become necrotic and can grow into normal skin, but necrosis may occur if the flap is damaged early in its life. Flap survival means that the flap is transferred to a new location, the blood supply is re-established, and the flap is integrated with the recipient area. Simply put, it means that the whole piece of tissue has changed to a new place to continue to survive. Once the flap has survived, most of it will not necrose if no abnormalities occur, at this time, you can observe that the flap is reddish in color, and the flap responds well to light pressure and engorgement. If the flap is activated and then traumatized by external impact or infection at an early stage, which injures the vascular tip, i.e., the area where the flap is connected, necrosis may occur. It is recommended that patients pay attention to the protection of the flap after the flap transplantation, pay attention to the observation of local blood circulation, skin temperature, skin color and other conditions, and keep the local clean, dry, and regularly change the medicine, avoid collision, extrusion, trauma and other conditions, pay attention to preventing the wound infection, in order to ensure that the flap survives normally.