Accurate diagnosis minimizes postoperative anal fistula damage Anal fistula is an ancient and common disease in anorectal surgery, and records of its treatment date back to the 4th century BC. There are tens of thousands of clinical cases treated each year in China, but the clinical outcome of anal fistula varies greatly due to differences in the level of diagnosis and treatment and philosophy, and the functional impairment of the anus is greater. In the domestic literature, the cure rate of high-grade complex anal fistula is 80%-90%, while foreign reports are only 30%-70%; the difference in reports of postoperative anal incontinence is even greater, with the incidence of anal incontinence reported to be only 5%-10% in China, while the incidence of anal incontinence in foreign patients with cut-and-link wires can be 30%-40%]. Why is there such a huge difference in treatment at home and abroad? There are still many questions that need to be answered in the diagnosis and treatment of anal fistula in China, such as what are the diagnostic and classification criteria for anal fistula? What are the principles of fistula treatment? It is undesirable to increase the trauma without limit in order to improve the cure rate, but it is also suspicious of physicians’ inaction to reduce the cure rate without limit in order to increase surgical safety. The treatment of anal fistula is a double-edged sword, and in this paper, the author discusses and considers the contradiction between balancing the cure rate of anal fistula and the rate of anal incontinence. The diagnosis and classification of anal fistulas seems to be an easy task, and many fistulas can be diagnosed simply by the experience of the physician. However, subjective examination alone does not preclude individual physicians from classifying patients with non-high complexity fistulas as high complexity fistulas in order to emphasize the complexity of the disease or because of inexperience. Because of the complexity of fistula treatment and the potential risk of anal incontinence during treatment, routine intracavitary ultrasonography or (and) magnetic resonance examination is recommended for patients suspected of having a high-grade complex fistula to clarify the extent and depth of the fistula and the relationship with the sphincter, which is important for guiding surgical treatment and postoperative follow-up. If possible, preoperative anorectal manometry can be performed, which is also an important reference for postoperative anal function prediction and postoperative follow-up. How to classify anal fistulas is another issue that deserves consideration. The commonly used domestic classification standard for anal fistula is the diagnostic standard for anal fistula developed in 1975, which divides anal fistula into high and low by the upper and lower anorectal rings, and into complex and simple by the number of external openings. Of course, if there are more external openings and fistulas, the more difficult the treatment will be, but not all fistulas with more than 2 external openings are very complicated to treat. In addition, in the domestic classification, a high anal fistula is one with a fistula above the anorectal ring, while a fistula below the anorectal ring is a low anal fistula. It is known that the sphincter below the anorectal ring includes the subcutaneous, superficial and deep external sphincter and most of the internal sphincter, and if so much of the sphincter is severed during surgery, the patient may be at risk of anal incontinence. Therefore, in the determination of the location of fistulas in China, the extent of low anal fistulas is too large, and if these “low anal fistulas” are subjected to any kind of sphincterotomy, there is a greater risk of anal incontinence. The classic diagnosis of high anal fistula and complex anal fistula is still used in many of our hospitals, and this diagnosis is limited in guiding the treatment of anal fistula. The most common international classification of fistulae is the Parks classification, which classifies fistulae into four categories based on the relationship between the fistula and the sphincter, namely intersphincter, trans-sphincter, extrasphincter, and suprasphincter fistulae. Keigley et al. refined the Parks classification to be more instructive. In general, a clinically meaningful classification is one that takes into account the relationship between the internal and external orifices, the fistula and the sphincter, and the fistula and the cavity in the diagnosis of anal fistula. In the treatment of anal fistula, there is also a balance between functional impairment and disease cure. The most common complications during anal fistula treatment are anal agenesis and anal incontinence. If the anus is functional but there is a slight anal defect, patients are often okay with this; after all, functional normalcy precedes structural perfection. For the treatment of anal fistula, preservation of anal function should be placed first in all treatment goals, and the impact of anal incontinence on life far exceeds the impact of anal fistula itself on the patient’s quality of life. In the author’s opinion: (1) for intersphincteric fistulas, the goal of treatment should be complete healing without any damage to anal function, and the more perfect goal is to minimize anal scarring; (2) for trans-sphincteric fistulas, try to choose a procedure with a high cure rate and maximum preservation of anal function; (3) for supra-sphincteric fistulas, any attempt to cut the entire sphincter may lead to The aim of treatment is also to minimize recurrent infections caused by fistula, and the main goal is not to cure the fistula; ④ Extra-sphincter fistula is often secondary to anorectal injury, Crohn’s disease, pelvic tuberculosis, pelvic abscess and other diseases. The specific treatment plan is set according to the specific situation. The choice of surgical method for anal fistula is consistent with the goal of surgery, and the key is to choose the right method for the right patient. The most basic procedures for anal fistula are anal fistulotomy and anal fistulotomy. Fistulotomy is often used for simple subcutaneous fistulas or intersphincteric fistulas, and the incision can even be sutured after surgical excision for better wound conditions and shorter healing times, but fistulotomy requires the removal of all fistula tissue and is relatively invasive and unsuitable for more complex fistulas. For fistulotomy, the fistula is incised to cure the fistula. For fistulas with low location and small sphincter removal, the incision can be performed directly; for fistulas with larger incisions, cutting and hanging wires are used to reduce the incidence of post-incision anal incontinence. Although the incidence of severe anal incontinence decreases significantly with the use of cutting and hanging wires, there is still a certain incidence of mild anal incontinence, especially in cases where more than 1/2 of the external sphincter is incised, and postoperative anal function is affected to some extent. The literature reports an incidence of anal incontinence of about 30-50% after anal fistula incision or anal fistula incision and hanging surgery, and even patients who do not develop anal incontinence immediately after anal fistula surgery are at a significantly increased risk of developing anal incontinence in old age]. To reduce anal incontinence due to anal fistula surgery, it is important not to attempt to cure some particularly complex anal fistulas, especially combined Crohn’s disease anal fistulas and tuberculous anal fistulas, which are often difficult to achieve by attempting to enlarge the surgery to achieve a cure. Can we achieve a cure for anal fistula without damaging the sphincter? Is there a way to cure a fistula without damaging the sphincter? Total sphincter preservation surgery is a new direction in the treatment of anal fistula, and the total sphincter preservation procedure can reduce postoperative anal function damage, but the clinical efficacy reports vary widely. Currently, the commonly used methods include bioprotein seal, anal fistula plug filling, drainage hanging, nudging mucosal flap or nudging skin flap, and ligation of trans-sphincteric fistula (LIFT). However, the success rate is only 10%-30%, and the recent long-term follow-up study may be even lower and may be gradually abandoned; fistula plugs are a new treatment method for anal fistula reported in recent years. The effect is not very satisfactory, but this procedure also has less damage to the sphincter muscle, even if it fails, you can operate again, the results of which have not been reported authoritatively, looking forward to the results of the clinical study of 500 cases in the United Kingdom; the anal fistula suppository produced by the United States COOK company has landed in mainland China, I hope not for various reasons “popular “The purpose is to keep the fistula drained and free from infection; the effect of mucosal flap and nudging flap in the treatment of anal fistula is more certain, the cure rate can reach more than 50-60%, and the possibility of anal incontinence is also low, but in some patients However, in some patients, it is difficult to create a nudge flap or nudge flap, and necrosis of the flap and serious infection may occur, so it is only suitable for some patients. The ligation of the intersphicteric fistula tract (LIFT) is a new completely sphincter-preserving procedure for the treatment of complex anal fistulas, reported by Rojanasakul in 2007, which closes the internal opening by ligating and cutting the fistula in the space between the internal and external sphincters, thereby This procedure is performed by ligating and cutting the fistula in the gap between the internal and external sphincters, thereby closing the internal opening, stopping the source of infection in the rectum, scratching to remove the necrotic tissue in the external remnants of the fistula, and achieving healing by drainage. Since the surgery is performed through the normal anatomical gap, the internal and external sphincters are not damaged and the postoperative decline in anal function is avoided; the surgical operation is relatively simple and does not affect the reoperation at all, and the operation time and hospital stay are significantly shorter than those of other procedures such as flap/mucosal flap. Aboulian et al. reported a success rate of 68% in the treatment of complex anal fistulas with LIFT. These procedures suggest that LIFT surgery seems to be a highly desirable procedure. In China, Wang Zhenjun reported a recurrence rate of 3.6% in 36 patients undergoing LIFT with a 3-month follow-up time, but the follow-up time was short and no controlled study was performed. In general, LIFT has obvious advantages compared with other surgical methods for treating complex anal fistula: it protects the anal sphincter, reduces tissue damage, shortens the healing time, has a small invasive surface, is simple to operate, and has a low cost, etc. Phase II has no obstacles to secondary surgical treatment after recurrence. Throughout the reports on LIFT surgery at home and abroad, the follow-up time is short and there is no randomized control group study, which lacks sufficient convincing power, and a large sample of randomized control study is needed to confirm its value and explore the methods and treatment plans adapted to total sphincter preservation surgery. In conclusion, in the diagnosis and treatment of anal fistula, the relationship between the internal orifice, external orifice, fistula and sphincter, and the relationship between the fistula and the cavity should be fully considered, and the relationship between functional damage and disease cure should be balanced, and surgery that can minimize damage to the sphincter is the preferred surgical method. Total sphincter preservation surgery is a new trend in anal fistula treatment, but there is still a lack of large randomized controlled studies in clinical practice, which needs to be further explored and promoted.