Anal fistula surgery silk thread is clinically called hanging thread, hanging thread does not fall off after anal fistula surgery, if it is a solid hanging thread can be tightened to expand the tension to make it fall off, if it is a false hanging thread can be used scissors to cut it off. 1. When the purpose of the hanging thread is to cut the anal fistula with the real hanging thread, if the hanging thread does not fall off, you can tighten the thread again to increase the tension of the hanging thread, when the hanging thread cuts the anal fistula, it will fall off by itself. 2. When the purpose of the hanging line is to use the virtual hanging line for drainage of pus, so the hanging line does not play a role in cutting, it will not fall off. In about 2~3 weeks after the operation, when there may be no secretion or pus in the fistula, you can use scissors to cut the hanging threads, and the fistula will heal on its own after the threads are removed. Recovery after anal fistula surgery often takes a long time, and patients are advised to keep the area around the wound clean and dry, change the medication in a timely manner, and have regular checkups to observe the healing of the wound. If there is any discomfort, inform the doctor as soon as possible for treatment.