There are two types of skin straps used in anal fistula surgery: the first type of skin straps are dummy straps, which are not tightly threaded and play a role in drainage, and can usually be removed 7-10 days after surgery. In the second case, a solid wire is used instead of a scalpel for cutting. This is because some high anal fistulas are likely to lead to anal incontinence once a one-time incision is made. Therefore, it is necessary to use a leather band to cut the tissue instead of the knife, so that it can let the tissue grow while cutting, so as to preserve the function of the anus to the maximum extent and not to cause postoperative anal incontinence. Therefore, this skin band needs to be tightly threaded after surgery, and usually within ten days to two weeks, this skin band will fall off naturally.