Anal Fistula Can Be Difficult To Treat

This model illustrates various pathology of the rectum. (iStockphoto/Thinkstock)
This model illustrates various pathology of the rectum. (iStockphoto/Thinkstock)

Last week, I was in San Francisco, California to attend the Clinical Congress (convention) organized by the American College of Surgeons. It is one of the largest surgical conventions in the world. The convention lasts five days (Sunday to Thursday). By Wednesday afternoon, total registration for the convention was 14,397: 8916 were physicians and the rest were exhibitors, guests, spouses and convention personnel.

Not everybody is in one auditorium or room at the same time. Each room has its own list of speakers and topics for discussion. So you head yourself to a room which offers discussion on a topic which interests you the most. The conference was held at the Moscone Convention Center. It is the largest convention and exhibition complex in

San Francisco. It comprises three main halls with total of 84,000 square meters of space (900,000 square feet).

One of the symposiums I attended was on surgical problems of anus and rectum: cancer, fistula, fissure and hemorrhoids. Today, I will review the subject of anal fistula (fistula-in-ano).

What is a fistula? A fistula is an abnormal tunnel connecting two body cavities (such as the rectum and the vagina) or a body cavity to the skin (like the rectum to the outside of the body). Fistulas are usually the result of infection, injury or surgery. With an anal fistula there is a tunnel between the anus (and/or rectum) to the skin. A peri-anal abscess has a 50 per cent risk of turning into a fistula.

Anal fistulas do not generally harm the body. They are mainly a nuisance with some pain or discomfort and irritating intermittent discharge of blood, pus or stool. They can form recurrent abscesses which may require drainage under local anaesthetic.

Most of the time the diagnosis of fistula is made on the basis of classical clinical history and physical findings. Examination of the rectum may show an opening of the fistula onto the skin, the area may be painful on examination, there may be redness, a discharge may be seen or it may be possible to explore the fistula using a fistula probe (a narrow instrument) and in this way it may be possible to find both openings of the fistula.

Treatment of the fistula depends on the presentation of the problem. If there is active infection or abscess then it needs to be treated with drainage of the pus and antibiotics. Once the infection is cleared the fistula can be treated surgically. If it is difficult to get rid of the infection then long term drainage can be established by inserting a seton – a length of suture material or thin rubber tubing is looped through the fistula which keeps it open and allows pus to drain out.

The treatment aim should be to prevent recurrence of fistula. Treatment depends on where the fistula lies, and which parts of the anal sphincter it crosses.

There are several options. Doing nothing – a drainage seton can be left in place long-term to prevent problems. But this does not cure the fistula. Fistula can be layed open under anaesthetic. Once the fistula has been layed open it will be packed on a daily basis for a short period of time to ensure that the wound heals from the inside out. Depending on the depth of the fistula, this option may affect continence if the fistula involves sphincter muscles. Most fistulas are superficial and can be layed open under local anaesthetic without much problem with continence.

Other methods of treating fistula are: using fibrin glue injection, using fistula plug, creating a flap to cover the internal fistula opening and using a seton to cut through the deep fistulous tract. Each method has advantages and disadvantages.

Some fistulas are very difficult to treat if they are caused by inflammatory bowel disease like Crohn’s disease. Any patient with recurrent fistula should be investigated for inflammatory bowel disease. Otherwise, most fistulas can be cured with patience and perseverance.

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