Anal fistula is usually a chronic inflammatory disease of the perianal area secondary to a ruptured perianal abscess or perianal abscess surgery, the size of the anal fistula surgical wound is not fixed, mainly according to the location of the fistula high and low, the complexity of the fistula to decide, usually 3cm-5cm, or it may be larger. Low, simple fistula wound is relatively small; high, complex fistula wound is generally larger. 1. anal fistula position high and low: anal fistula is mainly composed of internal, fistula, external, when the fistula walks in the external sphincter deep below, that is, low anal fistula, can be anal fistula incision or fistula excision, the wound is usually relatively small, in 3cm or so, if the fistula passes through the external sphincter deep above, the emergence of high-level anal fistula, need to carry out the low-level incision, high-level hanging surgery and other treatments, the surgical wound is relatively big, may be In 5cm or more. 2. anal fistula complexity: simple anal fistula is a mouth, a fistula, if it is complex anal fistula, there may be more than one fistula and mouth, simple anal fistula surgical incision is small, complex anal fistula surgical wound will be according to the number of fistula will be correspondingly larger. Anal fistula surgery wound due to the actual anal fistula situation is different, the size varies, it is recommended that the patient to the regular hospital, in the doctor’s diagnosis, according to the patient’s specific condition, to take targeted treatment.