After anal fistula surgery, the anus can not be closed tightly is usually due to the anal sphincter muscle damage, postoperative trauma scars, postoperative anal retraction function decline and other reasons. 1. Anal sphincter injury: anal fistula excision surgery can damage the sphincter muscle, resulting in patients with anal sphincter injury, the anus can not be tightly closed. 2. Postoperative wound scar: the wound scar after anal fistula surgery is large and the recovery time is long, due to the hardness of the scar, which may lead to the patient’s postoperative anus can not be tightly closed. 3. postoperative anal function decline: in the process of anal fistula surgery, may affect the local nerves and muscles, resulting in a decline in the function of anal retraction, resulting in anal fistula surgery after the anus can not be tightly closed symptoms. It is recommended that patients go to the hospital in time for examination, always observe the physical condition, under the guidance of the doctor symptomatic treatment, to slow down the symptoms of discomfort.