Gastrointestinal Fistula Clinical Trials

The goal of this clinical trial is to compare two different surgery methods for treating a complex type of anal fistula. This condition is an abnormal tunnel connecting the inside of the anus to the skin nearby. The main questions the study aims to answer are: Which surgery has a lower chance of the fistula coming back (recurrence)? Which surgery has a lower chance of causing problems with bowel control (incontinence) after healing? Researchers will compare two surgery groups: Group 1: Fistula Rerouting Technique - a two-step surgery that moves the fistula tract to a safer area before opening it. Group 2: LIFT Technique - a surgery that ties off and closes the fistula tract from between the anal muscles. Participants will be randomly assigned by a computer to one of these two surgery groups. This helps ensure the comparison between the two surgeries is fair. Participants in this study will: * Have tests before surgery, including an MRI scan, to confirm they have the specific type of fistula being studied. * Undergo one of the two planned surgical procedures. * Attend follow-up visits after surgery at 1 week, 2 weeks, 1 month, and 3 months. * Be checked during these visits for wound healing, pain, infection, and bowel control. * Have another MRI scan if the fistula is suspected to have come back.