Anal Fistula

What is an anal fistula? 
A fistula is an abnormal connection between two structures. In this case it is a connection between the inside of the rectum and the skin on the buttock. This usually starts with a boil (called a perirectal abscess) next to the anus. Most of the time these heal without problems. However, occasionally a permanent connection between the rectum and skin remains. Once this abnormal connection occurs, it will usually not heal on its own. It may cause continued drainage, discomfort, or recurrent infection. Any time this kind of fistula is present, it should be taken care of surgically.

What is the operation like?
This kind of surgery is usually done as an outpatient. This operation can be done with local anesthesia (novocaine), spinal anesthesia, or general anesthesia (asleep). In addition a long acting local anesthetic is injected to minimize discomfort during the first eight to twelve hours after the operation.

The procedure consists of finding both the inside and outside openings of the "tunnel", and placing a small metal probe (or wire) through the tunnel. Unfortunately, we can not just sew the ends of the tunnel closed, because the fistula will just come back. It is necessary to "un-roof" the tunnel. This means removing the skin and muscle that separates the tunnel from the anal opening. This is then left open, and the body's normal mechanisms for healing will fill in the defect.

What is recovery like ?
The amount of discomfort a patient will have is difficult to predict. Everyone seems to be different in this respect. Some patients feel that the post operative discomfort is not much worse than the pain they had from the fissure itself.

It is important to avoid constipation after the surgery. This will minimize the discomfort with bowel movements. Moist surgeons recommend a bulk laxative such as Metamucil, Fibercon or Citrucel for about 2 months after the hemorrhoidectomy.

Although there are no real restrictions on activity after the surgery, most patients take about five to seven days at home to recuperate.

There are two problems that can occur that are unique to this operation. The first is that the fistula could come back. Sometimes, as the postoperative healing occurs, the tunnel re-forms. If that happens, it will be necessary to re-do the operation. 

The other problem is related to control of the stools after the surgery. There are several muscles around the anus and rectum that control opening and closing the anus. Sometimes the fistula goes through or under these muscles and it is necessary to divide the muscle in order to open up the fistula. Because of this there can be some degree of loss of control of stools after the operation. Usually, this is no more severe than some occasional moisture on the underclothes for the first few days. Any permanent loss of control is very unusual.

Steven C. Immerman, M.D., FACS © 2000