The hanging thread technique is to use materials such as medicine thread and rubber band to selectively bind to the fistula tract, drainage or slow cutting to treat anal leakage and canker, etc. Especially for the treatment of high anal leakage, the damage to the sphincter is small and the anal function is better maintained. A. Commonly used apparatus 1. rubber band 2. silk suture 7 or 10 non-absorbable surgical suture. 3.Probe Ball-headed silver or copper probe. (a) Drainage and hanging technique 1.Indications Drainage of anal fistula and perianal abscess. 2. Preoperative preparation Preoperative skin preparation and enema cleaning of the lower rectum. 3. Position Lateral or truncal position. 4., anesthesia mode Lumbar point anesthesia. 5. Surgical steps (1) Drainage and hanging of perianal abscess: after the abscess fluctuates obviously or drains out the pus under the guidance of ultrasound in the cavity, separate the interval in the abscess cavity with fingers, and use drainage and hanging of the line for the abscess that affects several interstices. The abscess cavity is explored from the incision with curved vascular forceps, and one or more incisions are made next to the anus to facilitate drainage and avoid damage to the sphincter, and rubber bands or multi-stranded silk threads are introduced to form a loop respectively to keep the drainage in a relaxed state. For abscesses with a clear internal opening, a probe can be inserted through the abscess cavity and a rubber band or silk thread introduced through the internal opening for marking or second-stage incision. After the operation, daily flushing and drug changes are performed until the redness and pain subsides and there is no obvious pus, the drainage is removed and the pad is wrapped with cotton method until the abscess cavity is closed. (2) Anal fistula drainage hanging line: determine the drainage hanging line site according to the location, number and relationship between the fistula and the sphincter. The ball probe is inserted into the fistula at the external opening, and if the external opening is temporarily occluded, a slight incision can be made, and the fistula can be passed through to the main tube, then the fistula can be scraped with a spatula to remove the carrion tissue, and then the ball probe is placed into the tube, and the tip of the probe is connected to 10 strands of No. 7 medical silk and then introduced into the fistula tract to keep the wire loose. Multiple branches can be treated in the same way. After the operation, the wire can be removed in stages when the purulent discharge is reduced, and the wire can be removed with the cotton pad method until the fistula is closed. (2) Cutting and hanging technique 1. Indications High anal fistula, complex anal fistula. 2. Preoperative preparation, position and anesthesia: the same as the drainage technique. 3, surgical steps ① probe of the internal port: anal finger examination through the anal canal skin palpable fistula, near the tooth line can be palpable hard nodes or depressions, often the internal port; or staining method, the rectum of the anal canal filled with gauze, from the external port injection of methylene blue solution, the filled gauze stained blue can determine the existence and location of the internal port; the most commonly used probe method, the left hand index finger into the anus, the right hand holding a ball probe from the external port of the fistula probe, along the route of the fistula gently and gently. The most common method is to place the index finger of the left hand into the anus, and the ball-tipped probe of the right hand into the external orifice of the fistula and gently and carefully search for the internal orifice along the fistula. If the probe reaches the mucous membrane of the internal orifice and cannot be directly probed out, the probe should be withdrawn slightly and probed into the adjacent saphenous fossa, if still not sure, the suspected anal sinus can be probed with a saphenous hook under the anoscope, if the depth of the anal saphenous fossa is more than 25px, it is mostly the internal orifice, and continued probing can often meet with the probe and guide the probe to probe out from the internal orifice. For those who do not recover from multiple treatments or have complicated recurrent episodes, preoperative fistulography, endorectal ultrasound or magnetic resonance imaging should be performed to help determine the fistula pathway and the location of the internal orifice. ②Cut and hang wire: Probe the fistula from the external opening, cut the skin and subcutaneous along the fistula alignment, remove the carrion or wall of the fistula, expose its sphincter portion, and leave the hang wire in place. The fistula is then removed from the skin and subcutaneous skin along the path of the fistula to reveal the sphincter. For complex fistulas or fistulae with one internal opening, a tight thread can be hung between the internal opening and the main fistula, and the fistula can be closed using the Chinese medicine method. For complex fistulas with multiple internal openings, they can be threaded separately, but only one thread can be tightened at a time and according to the thickness of the sphincter, the superficial fistula should be tightened first to minimize damage. When tightening the thread, compound lidocaine injection can be used in the muscles around the threaded area and at the wound edge to reduce pain. Special tips: 1. For high anal fistula and perianal abscess, preoperative ultrasound or magnetic resonance imaging of the rectal cavity should be performed if possible to clarify the extent and depth of the abscess, the fistula and the location of the internal opening. 2. To protect anal function, the cutting and hanging of sphincter tissue should be minimized. The rubber band will fall off after 7-10 days for superficial fistulas; for high fistulas, multiple tightening should be used, 2-4 mm each time. 3. Daily herbal fumigation baths and medication changes. The wound should be observed when changing the medication, so that the wound gradually heals from the base upwards to prevent bridge-shaped healing. Contraindications 1. rectovaginal fistula. 2.Anal fistula with malignant transformation or due to malignant tumor. Precautions 1.For patients with high perianal abscess with unclear internal opening, only hanging line drainage is performed, and after marking, second stage incision or cutting and hanging line is performed. 2.For multiple anal fistulas with multiple internal openings, they can be treated by hanging wires separately at the same time and alternating tight wires to avoid simultaneous incision, reduce damage and maintain anal function. 3, anal fistula trauma deeper need to wait for the trauma surface to reduce the tightening of the line. 4.If the internal opening is large, multiple strands of silk thread can be used for hanging and drainage, and gradually removed as the trauma shrinks until it heals.