Dragline procedure Indications: For complex anal fistulas with multiple ducts (branches). Main method: Place silk threads, skin pieces, and glue tubes between the inner and outer openings (fistulas) to make a loop, rotate and drain to avoid residual pus decaying tissue and necrotic detached tissue, and cooperate with flushing and compression of the fistula. The duration of drainage is usually 14 days. Advantages and disadvantages: No skin incision, no muscle cutting, maximum protection of anorectal tissue, reflecting the concept of “minimally invasive” treatment. It requires high requirements for perioperative dressing change. Line drainage This method is a sphincter-preserving procedure developed on the basis of dragline surgery, which is divided into three stages. The first stage: 7-day “wire” drainage, using 10 strands of silk wire thick drainage, can be decomposed with drugs, but has residual lumen and other hidden problems, and pain is more obvious. The second stage: 7 days “tube” drainage, with a small hole with a thin tube drainage, less painful, with a spraying effect. The third stage: 5 days “pressure closure”, generally control the stool for 2 to 3 days, pad cotton sitting pressure for 4 to 5 days, in order to achieve the role of pressure closure of the tube lumen.