The depth of the anal fistulotomy wound is generally related to the depth of the fistula. In most cases, anal fistulotomy is a low level fistula, so the depth of the wound is mostly within 1~2cm. Anal fistulotomy mainly refers to the fistula completely cut or excision, through the later growth of granulation tissue, wound healing to completely heal the anal fistula, mainly applicable to the treatment of low anal fistula, mucous membrane or subcutaneous fistula of the anal canal. Due to the low fistula location is relatively low, usually in the anal canal external sphincter deep below, surgical incision generally only damage the superficial part of the external sphincter, so the depth of the wound after surgery is shallow, mostly within 1 ~ 2cm. After incision of anal fistula need to be in the wound Vaseline gauze filling, to promote the growth of traumatic granulation tissue and to avoid wound closure to form pus cavity, so the postoperative need to be regular wound cleaning and changing and keep the wound clean and dry, and comply with the doctor’s instructions for treatment.