Anal fistula is an infected channel between the anal canal and the perianal skin, consisting of three parts: internal opening, fistula, and external opening. Mainly violates the anal canal, rarely involves the rectum, after a long time, is a common disease in the anorectal diseases, the rate of disease is second only to hemorrhoids, any age can be onset, mostly seen in young and middle-aged men. Etiology The cause of anal impotence is mostly generalized purulent infection, a few for tuberculosis, Crohn’s disease, ulcerative colitis, malignant tumors, anal canal trauma, etc. can also form anal fistula. Most of the anal impotence from the perirectal abscess, when the abscess breaks down or cut and drain the place to become the outer mouth; abscess shrinkage, the formation of infected pipes, the primary lesion becomes the source of infection into the pipe mouth, so long-lasting. The outer mouth of the skin grows faster, often false healing, so that it breaks out again, repeated attacks. Symptoms of anal fistula 1, pus The amount and nature of pus is related to the length of the fistula, thickness, and the size of the inner mouth. Generally more pus in the early stage, thick, smelly, yellow color, with the prolongation of time pus reduction, or sporadic, intermittent pus. 2, pain If the fistula drainage is smooth, generally do not feel pain, only feel anal discomfort, walking aggravated. If the external mouth is temporarily closed, or the drainage is not smooth, pus accumulation, local distension or throbbing pain may occur. 3, itching With repeated stimulation of secretion, perianal skin is moist and itchy, even causing anal eczema, skin papules or epidermal shedding. Long-term non-healing may lead to thickening of the skin to become mossy. 4, defecation General anal fistula does not affect defecation. High complex anal fistula or horseshoe fistula due to chronic inflammatory stimulation caused by anorectal ring fibrosis, or fistula around the anal canal to form a semi-circular fibrous strips, affecting the anal sphincter diastasis and the emergence of defecation. Treatment Anal fistula can not be self-healing, traditional Chinese medicine and drug treatment is not effective, whether it is a low anal fistula or high anal fistula, must be surgical treatment of anal fistula. 1, fistulotomy is suitable for fistula belonging to the inter-sphincter type or sphincter type of shallow part of the anal fistula, cut only part of the internal sphincter or external sphincter damage to the lower part of the skin and shallow, will not cause postoperative anal incontinence. 2, hanging line therapy is a slow incision method, the use of rubber bands of mechanical compression, so that the ligature at the gradual necrosis of tissue compression, in the fistula surface tissue cutting process, the basal wound at the same time gradually healing, the ligature line can be used as a fistula drainage, so that the fistula seepage discharge, to prevent the occurrence of acute infection of anal fistula. The biggest advantage of this method is that the anal sphincter is gradually cut, but not due to excessive contraction and position change, generally does not cause anal incontinence, and easy to operate, less bleeding, easy to change the medication, the patient’s pain is small, is the most commonly used anal fistula surgical method. 3, anal fistula excision for low simple anal fistula. After cutting the fistula, the fistula wall will be removed to the healthy tissue, and make the wound inside small outside large, generally do not suture.