Causes of recurrence after anal fistula surgery Recurrence after anal fistula surgery refers to the re-formation of an anal fistula in situ after anal fistula surgery, not to the formation of a new anal fistula in another part of the perianal area. The causes of postoperative recurrence are different for low anal fistula and high anal fistula. The first one is that the inner mouth of the surgery is not found or treated properly, especially in the case of simple hanging threads that may lead to the inner mouth not being treated properly. 3. Individuals who originally had perianal purulent sweat glands were operated on as anal fistulas, and then the sweat glands became inflamed again. This is not much, but I have encountered several cases. Second, high anal fistula 1, again, is a problem of the internal opening. 2. The blind stump of the fistula can form an anal fistula again. Unlike low-grade fistulas, high-grade fistulas can be very complicated, with some being very deep and some leading directly to the rectal wall. Some have multiple branches forming a horseshoe shape. The surgical approach to high anal fistulae as described in textbooks and in the anorectal literature remains the same: hanging a wire from the internal opening, scratching the fistula, and opening the fistula. However, in patients treated with this procedure, there is a recurrence rate of 10-20% (reported in domestic and international literature), although the internal port is well treated. Of the 31 cases of high anal fistulas done by total fistula excision in recent years, only one case was cured by simple incision because the internal opening was not found during the operation and then formed a low anal fistula, and the rest were cured without recurrence. In one case, the deepest fistula was found to be straight through the rectal wall, forming a small hole in the posterior rectal wall, which was repaired by cutting off this part of the posterior rectal wall.