The main goals of treatment are to drain the pus, cure the fistula, and protect the integrity of the sphincter and the function of the anus. Most low-grade fistulas can be cured by incision or excision. At the same time, anal function can be preserved. However, the management of high-grade complex fistulas is more difficult because when the fistula passes through the upper 1/2 of the anal sphincter, the fistula alone can cause anal incontinence, and in such patients, sphincter-preserving surgery is required, including transanal rectal flap closure, perianal flap repair, and sphincter repair with excision (excision) of the high-grade fistula. The most traditional and convenient method is the seton. The word seton, which originated from the Latin word seta, meaning animal mane, now refers to any material used to cross a fistula, including silk, nylon, polyester, rubber, silicone rubber and plastic, metal wire, and herbal threads (twists). The thread can be loosely hung to mark and promote fibrosis for short and long term drainage. It is also possible to tighten the thread gradually to achieve the purpose of slowly cutting the sphincter. The role of the threads is mainly antibacterial, anti-inflammatory and promote the healing of anal fistula. History: The exact origin of surgical threads is not known. Sushruta, an Indian surgeon, was the first to use thread therapy in 600 B.C. by inserting a thread into a fistula. By 460-377 B.C. Hippocrates advocated wire cutting, and in the 11th century Albucasis followed the wire with fistulotomy. 1376 Arderne proposed a modified second-stage wire technique for the treatment of anal fistulas. 1873 Dittel in Vietnam was the first to report the advantages of using India rubber ligatures for the treatment of anal fistulas, Eighteen months later William Allingham of St Mark’s Hospital was inspired by Dittel’s work. The experience of applying the elastic ligation method for the treatment of anal fistulas in 60 cases was published at the London Medical Society and formally published in 1875. The first surgeon to resume the use of the hanging wire method in the 20th century was Pennington (1908). There are several methods of hanging wires for the treatment of anal fistulas. The different techniques used worldwide over the past 90 years are discussed and reviewed below. The different sutures used in surgery today include chemical sutures, sutures for drainage, sutures for excision and second stage sutures for fistulotomy. Traditional Indian medicine has used chemical threads to treat anal fistulas. In 1973, Deshpande reported 200 cases of fistulas treated with chemical threads and 193 cases were cured, and the authors concluded that the recurrence rate after threads was better than that after surgical excision. Moreover, this method was also successfully applied in the treatment of high anal fistulas and reported a cure rate of 96% (Deshpade 1976). The application of medicated thread therapy for the treatment of high anal fistulas results in a neat linear scar after healing, whereas surgical excision results in the formation of a deformity. Shukla (1991) in a randomized controlled study comparing 502 cases of low and high anal fistulas treated with Indian thread therapy and conventional surgery concluded that the recurrence rate and incidence of anal incontinence were comparable between the two, but the mechanism is not known and may be related to the alkalinity of the threads and suggested that the three herbal components have anti-inflammatory, antibacterial and promote wound healing. This traditional treatment for anal fistula is easier and less expensive than inpatient surgery, and does not affect work. 2. Hanging wire drainage Long-term hanging wire drainage method: It is mainly used for hanging wire drainage of perianal rectal abscess. The University of Minnesota Hospital reported that 55 cases of anal fistulas secondary to Crohn’s disease were treated by the hanging wire drainage method, of which 22 cases were high-grade complex anal fistulas and 19/22 cases remained in the resting stage after hanging wire drainage. Williams (1991) reported that 23 cases of Crohn’s fistulas were treated with wire drainage, with a recurrence rate of 39%. In recent years, long-term line drainage has also been effective in the treatment of perianal abscesses of the anorectum secondary to AIDS. Short-term wire drainage: Before the sphincter-preserving technique, Park’s and Stitz reported in 1976 that short-term wire drainage was also effective in the treatment of high-grade anal fistulas. Thompson (1989) reported a 44-86% success rate in 34 cases of high trans-sphincteric fistulas treated with short-term nylon wire drainage, and a 44% cure rate. Williams (1991) reported 14 cases of high-grade fistulas treated with short-term drainage with a recurrence rate of 14%. St Mark’s Hospital Buchaman reported a 30% recurrence rate at 6 months, 55% at 15 months, and 75% at 60 months for complex fistulas treated with short-term drainage. Although temporary line drainage is effective in the treatment of complex fistulas, preserving the integrity of the sphincter and not causing anal incontinence, its success rate decreases with longer follow-up and its efficacy is uncertain. Therefore, the patient should be consulted and followed before the decision is made to perform a line drainage. Although some patients can be cured with this method, many patients will have a recurrence of abscess and require further surgery. The mechanism of the hanging wire cutting method is to use the elastic tension of the hanging wire to slowly cut the sphincter, and the fibrosis formed after cutting ensures that the sphincter does not separate at the severed end. There are two methods of cutting the hanging wire (1) one-stage hanging wire cutting method. Cutting is achieved by maintaining static tension or gradually tightening the thread. In 1927, Buie reported the use of silk thread as a cutting wire for the treatment of high anal fistulae, but there was a lot of tissue damage. 57 years later, Dr. Culp of the Mayo Clinic used elastic hanging wire material to treat 20 cases of complex anal fistulae with good results in terms of anal self-control, one case had mucus leakage and two cases had intermittent fecal incontinence, but it did not affect work and social activities. Williams at the University of Minnesota Hospital reported 13 cases of high anal fistulae treated by wire hanging with no recurrence at 24 months of follow-up, but 7 of them had mild anal incontinence. Isbister reported 47 cases of trans-sphincteric fistulas treated by the wire-cutting method with an average follow-up of 1.1 years, one recurrence and 30% anal incontinence, and Ustynoski reported 18.1% recurrence rate in horseshoe fistula abscesses treated by the wire-cutting-to-oral drainage method. Despite the cure of anal fistulas by the one-stage incision and hanging wire method, 50-62% of patients have anal incontinence, which is mild but does not improve with time, and the anal deformity caused by scar formation is an important factor in anal incontinence. Therefore, McCourtney and colleagues advocated nylon hanging line drainage followed by removal of the fistula and immediate sphincter stage I reconstruction. (2) The second stage (staged) wire-cutting method consists of fistulotomy followed by wire-cutting, or wire-hanging drainage followed by tight wire-cutting. Many scholars have used silk thread or other materials to hang thread and tighten it in stages to treat complicated anal fistulae, and Hanley used rubber band to hang thread to treat 35 cases of female fistula abscesses. It takes 6-8 weeks for the sphincter to be completely cut, and the patients treated by this method have good anal function and little damage. Allen and Haskell reported 119 cases of complex anal fistulas treated successfully with this classic second-stage procedure. Williams used this technique to treat 24 cases of high anal fistulae with an 8% recurrence rate and a 54% incidence of minor anal incontinence. Pearl reported 116 staged fistulotomies with an overall recurrence rate of 3% and an anal incontinence rate of 5%. Proponents of staged fistulotomy argue that this technique is superior to staged fistulotomy because of the pain and uncontrollable sphincter severance associated with the latter. The Garcia-Aguilar study concluded that there was no significant difference between the wire-cut and the staged fistulotomy in terms of abscess cure and prevention of anal incontinence. The surgeon’s personal experience and preference ultimately determines which wire method is used. Threaded fistulas have been treated for thousands of years and have been shown to be successful in the treatment of complex fistulas and perianorectal abscesses, both abroad and in the past. In particular, wire-cutting is the easiest way to cure high-grade complex fistulas. It is also important in the treatment of perianal abscesses associated with Crohn’s disease and in immunodeficient patients. Modern surgery believes that the wire technique still plays an important role in the treatment of anal fistulas. Therefore, hanging wire treatment is one of the important treatment tools that we should learn well.