Chronic anal fissure: old fissures in the skin of the anal canal, accompanied by anal papillary hypertrophy and sentinel hemorrhoids. Clinical symptoms of anal fissure 1. Pain: Pain is the main symptom of anal fissure, characterized by anal pain during defecation, followed by brief pain relief. Then more intense persistent anal pain occurs, which can last for several hours. We call this intermittent pain. 2. Bleeding: Anal fissures do not bleed much, and there is blood dripping from the anus during stool or blood on hand paper. 3. Constipation: Due to the fear of anal pain, patients try to reduce the number of bowel movements, resulting in prolonged retention of fecal masses in the rectum and absorption of water, forming constipation. Treatment of anal fissures: For fresh anal fissures, usually not longer than one month, conservative treatment can be taken, including keeping the stool open, using some ointment outside the anus, Chinese herbal sitz bath, local closed anal injection, etc. can be subject to good results. For chronic anal fissure, the Department of Proctology of our hospital adopts the treatment of anal fissure by cutting off part of the internal anal dilator muscle, which has short operation time, less pain and good clinical effect.