Fistula surgery is a procedure to close or remove an abnormal tunnel that forms between two body parts that shouldn’t be connected. The most common type treats anal fistulas, which are tunnels between the inside of the anal canal and the skin near the anus. But fistula surgery also includes creating a deliberate fistula in the arm for dialysis access, or repairing fistulas that develop between the bladder and vagina after childbirth. The specific technique depends entirely on where the fistula is, what caused it, and how complex the tunnel has become.
Why Fistulas Form
An anal fistula usually starts as an abscess, a pocket of infection in one of the small glands inside the anus. When that abscess drains (on its own or with help), it can leave behind a tunnel that refuses to heal. The tunnel keeps draining fluid, causing pain, swelling, and recurring infections. About 30 to 50 percent of anal abscesses eventually develop into fistulas. Conditions like Crohn’s disease significantly increase the risk.
Other fistulas form for different reasons. Vesicovaginal fistulas, tunnels between the bladder and vagina, most commonly result from prolonged obstructed labor during childbirth, especially in regions with limited access to emergency obstetric care. These cause continuous urinary leakage. Fistulas can also develop after pelvic surgery, radiation therapy, or as a complication of inflammatory bowel disease.
How Surgeons Diagnose the Problem
Before any fistula surgery, imaging helps map out exactly where the tunnel runs and whether it branches. For anal fistulas, MRI is the gold standard. It has about 90% sensitivity and 100% specificity for identifying the type and extent of the fistula tract. This matters because missing a hidden branch during surgery is one of the main reasons fistulas come back. Your surgeon may also do a physical exam under anesthesia, using a probe to trace the tunnel’s path.
Surgical Options for Anal Fistulas
There are several approaches, and the right one depends on how much of the anal sphincter muscle the fistula passes through. Simpler fistulas that involve only a small amount of muscle can be treated with straightforward procedures. Complex fistulas that cut through a significant portion of the sphincter require techniques that prioritize preserving your ability to control bowel movements.
Fistulotomy
This is the most common surgery for simple anal fistulas. The surgeon inserts a probe through the tunnel, then cuts open the entire tract from the inside, essentially converting the tunnel into an open groove. The wound is left open to heal from the bottom up. Because the tract is laid open rather than removed, the wound is smaller and heals faster than with other approaches. It has the highest success rate of any technique for simple fistulas, but it does cut through some sphincter muscle, which limits its use for fistulas that involve a large portion of the sphincter.
Fistulectomy
Instead of laying the tract open, the surgeon cores out the entire tunnel and surrounding tissue, removing it completely. This takes longer in the operating room because the tract must be carefully dissected away from surrounding tissue, and the internal opening must be closed. The advantage is that the removed tissue can be examined under a microscope, which helps rule out other conditions and ensures no secondary tracts were missed. Incontinence after fistulectomy ranges from about 11.5 to 20%, though the vast majority of those cases are mild, things like occasional difficulty controlling gas rather than significant loss of bowel control.
Seton Placement
A seton is a thin thread or rubber loop passed through the fistula tract and tied in a loose circle. It keeps the tunnel open so it can drain rather than forming another abscess. Setons are often used for complex fistulas as either a first step before definitive surgery or as a long-term solution on their own. The average time a seton stays in place is about 37 weeks, though the range is wide, from 6 weeks to over three years. A five-year study comparing cutting setons to other techniques found recurrence rates around 27%, which was statistically similar to more complex repairs.
LIFT Procedure
The LIFT procedure targets the fistula tract where it passes between the two rings of sphincter muscle. The surgeon makes a small incision between the muscles, finds the tract, ties it off on both sides, and cuts the portion in between. Because the sphincter muscles themselves aren’t cut, continence is well preserved. Success rates range from 60 to 94%, with about 23% of patients experiencing recurrence. Wound healing typically takes up to eight weeks.
Advancement Flap Repair
For this technique, the surgeon cuts a small flap of tissue from the rectal wall, cleans out the fistula tract, and covers the internal opening with the flap. This avoids cutting through sphincter muscle entirely. Recurrence rates hover around 24%, comparable to seton-based approaches.
Laser Closure
A newer option uses a laser fiber inserted into the fistula tract. The laser delivers energy in all directions, destroying the lining of the tunnel and causing it to shrink and scar closed. It’s gentle on the sphincter muscles, making it attractive for complex fistulas. However, the primary healing rate sits around 57 to 60%, lower than traditional surgery. Its main appeal is that it’s repeatable if the first attempt doesn’t work and carries very low risk of incontinence.
Dialysis Fistula Surgery
This is an entirely different type of fistula surgery. Rather than closing an unwanted tunnel, the surgeon deliberately creates one by connecting an artery to a vein in your arm. The high-pressure arterial blood flow causes the vein to enlarge and thicken over time, creating a durable access point that can be punctured repeatedly for dialysis.
The most common version connects the radial artery to a vein near the wrist. If those vessels aren’t suitable, the surgeon moves up to the elbow area, connecting the brachial artery to a larger vein. In some cases, a deeper vein must be surgically repositioned closer to the skin surface so it can be accessed with a needle, which may require one or two separate operations.
After creation, the fistula needs time to mature before it’s usable. The standard benchmark is the “Rule of 6s”: six weeks after surgery, the fistula should have a blood flow rate of at least 600 milliliters per minute, a diameter of at least 6 millimeters, and sit no deeper than 6 millimeters below the skin. If two-stage surgery was needed, the fistula matures for 6 to 8 weeks between operations.
Obstetric Fistula Repair
Surgery to repair a fistula between the bladder and vagina involves closing the abnormal opening, usually through a vaginal approach. The surgeon separates the bladder wall from the vaginal wall, closes each layer individually, and sometimes places a flap of tissue between them to reinforce the repair. A catheter stays in place afterward to keep the bladder empty while healing occurs. Research shows that 7 days of catheterization works just as well as 14 days, with fistula breakdown rates under 4% either way. Closure rates using dye tests to check for leakage range from about 69 to 90%, depending on the repair technique and whether tissue flaps are used.
What Recovery Looks Like
Recovery after anal fistula surgery revolves around wound care and pain management. Most procedures are done as day surgery, meaning you go home the same day. You’ll likely have some drainage from the wound for days to weeks, and wearing a soft gauze pad is standard. Sitz baths, sitting in a few inches of warm water for 20 minutes, are a cornerstone of healing. The general recommendation is three times daily plus after every bowel movement.
Pain is usually most intense during bowel movements in the first week or two. Stool softeners and a high-fiber diet help significantly. Most people return to desk work within one to two weeks, though physically demanding jobs may require longer. Complete wound healing after a fistulotomy or fistulectomy typically takes several weeks, and your surgeon will monitor for signs of recurrence during follow-up visits.
For dialysis fistula surgery, recovery is quicker in terms of pain, but you’ll need to wait at least six weeks before the fistula can be used. During that time, you may be asked to do hand-squeezing exercises to encourage blood flow and help the vein mature. The surgical site in your arm generally heals within a couple of weeks.
Recurrence and Long-Term Outlook
The biggest concern with anal fistula surgery is recurrence. No technique completely eliminates this risk. Simple fistulotomy for straightforward fistulas has the lowest recurrence rates, generally under 10%. More complex fistulas treated with sphincter-sparing techniques see recurrence in roughly 20 to 27% of cases, regardless of whether the approach is a LIFT procedure, advancement flap, or cutting seton. Patients who need additional procedures during the healing period, such as draining new collections or replacing a seton, face about seven times the risk of recurrence or treatment failure.
For dialysis fistulas, the long-term concern is keeping the access functional. Fistulas can narrow or clot over time, sometimes requiring additional procedures to reopen or revise them. Still, a well-functioning arteriovenous fistula lasts longer and has fewer complications than other dialysis access options, which is why surgical creation remains the preferred approach for long-term dialysis patients.