Anal fistulas are fairly common in people who have had an anal abscess. It's important to treat an anal fistula to reduce the chance of reinfection. Effective treatment also relieves accompanying symptoms. Patients treated for anal fistulas at Colorectal Physicians & Surgeons of PA benefit from skilled surgeons experienced in treating the most complex fistulas. Patients also have access to newer treatments, such as fibrin glue, collagen fistula plug and LIFT procedures.

An anal fistula is a small tunnel (tract) with an internal opening in the anal canal and an external opening in the skin near the anus. It forms when an anal abscess that's drained (either on its own or via surgery) doesn't heal completely.

Anal fistulas are classified by their location in relation to the anal sphincter muscles. They are listed from most common to least common:

• Intersphincteric fistula. The tract begins in the space between the internal and external sphincter muscles and opens very close to the anal opening.
• Transphincteric fistula. The tract begins in the space between the internal and external sphincter muscles or in the space behind the anus. It then crosses the external sphincter and opens an inch or two outside the anal opening. These can wrap around the body in a U-shape, with external openings on both sides of the anus (called a horseshoe fistula).
• Suprasphincteric fistula. The tract begins in the space between the internal and external sphincter muscles and turns upward to a point above the puborectal muscle, crosses this muscle, then extends downward between the puborectal and levator ani muscle and opens an inch or two outside the anus.
• Extrasphincteric fistula. The tract begins at the rectum or sigmoid colon and extends downward, passes through the levator ani muscle and opens around the anus. These fistulas are usually caused by an appendiceal abscess, diverticular abscess or Crohn's disease.

A history of recurring anal abscess with drainage is a clue that a person may have an anal fistula. The external opening usually appears as a red, inflamed spot that oozes pus, sometimes mixed with blood.

The location of the external opening gives a clue to a fistula's likely path, and sometimes the fistula can actually be felt as a hard cord. In many cases, however, visualizing its path may take various tools, and sometimes the path may not be clear until surgery.

Tools doctors may use include:

• Fistula probe. An instrument specially designed to be inserted through a fistula
• Anoscope. A small instrument to view the anal canal

If a fistula appears particularly complicated or in an unusual place, doctors may also use:

• Hydrogen Peroxide. Injected into a fistula
• Fistulography. Injection of a contrast solution into a fistula and then X-raying it
• Magnetic Resonance Imaging - to image the fistula tract
• Trans-Rectal Ultrasound

To rule out other disorders such as ulcerative colitis or Crohn's disease, doctors may use:

To rule out other disorders such as ulcerative colitis or Crohn's disease, doctors may use:

• Flexible sigmoidoscopy. A thin, flexible tube with a lighted camera inside the tip allows doctors to view the lining of the rectum and sigmoid colon as a magnified image on a television screen
• Colonoscopy. Similar to sigmoidoscopy, but with the ability to examine the entire colon or large intestine 

The goal of treatment is to cure the fistula with as little impact as possible on the sphincter muscles. The plan will depend on the fistula's location and complexity, and the strength of the patient's sphincter muscles.  

Fistulotomy
The surgeon first probes to find the fistula's internal opening. Then the surgeon cuts the tract open, curettes it (scrapes and flushes out its contents), then stitches its sides to the sides of the incision so the fistula is laid open (flattened out). To treat a more complicated fistula, such as a horseshoe fistula (where the tract extends around both sides of the body and has external openings on both sides of the anus), the surgeon may lay open only the segment where the tracts join and remove the remainder of the tracts. If a significant amount of the sphincter muscle must be cut, the surgery may be performed in more than one stage. It may also need to be repeated if the entire tract can't be found.  

Advancement Rectal Flap
Sometimes, to reduce the amount of sphincter muscle cut, a surgeon may core out the tract and then cut a flap into the rectal wall to access and remove the fistula's internal opening. The flap is then stitched back down.  

Seton Placement
The surgeon uses a seton (silk string or rubber band) to either: 

• Create scar tissue around part of the sphincter muscle before cutting it with a knife
• Allow the seton to slowly cut all the way through the muscle over the course of several weeks

The seton can also help the fistula drain.  

Fibrin Glue or Collagen Plug
In some cases, a doctor may use fibrin glue, made from plasma protein, to seal up and heal a fistula rather than cutting it open. The doctor injects the glue through the external opening after clearing the tract and stitching the internal opening closed. The fistula tract can similarly be sealed with a plug of collagen protein and then closure of the internal opening.  

LIFT
Ligation of Intersphincteric Fistula Tract (LIFT) is a new procedure. The midportion of the fistula is surgically isolated and stitched closed, allowing the internal and external openings to collapse and heal.

To make an appointment with a doctor from Colorectal Physicians & Surgeons of PA, please call 814-453- 2777.