Fistula Surgery

What is fistula in ano?

There are anal glands in the muscles surrounding the anus & rectum. These glands can get infected & form pus. This pus can then spread in various directions & form an abscess. When these abscesses (pockets of pus) burst or when they are incised, they form a tract which is known as fistula in ano (see animation). These tracts have an internal opening in the anus & an external opening outside on the skin. The site of the external opening depends on the spread of the infection. Usually they are situated around the anus, but could be located as far away as the groin, abdomen & thigh. Uncommonly fistula can be due to tuberculosis, Crohn’s disease or cancer. Rarely one can develop a fistula between the anus/ rectum & the urethra or vagina. This is usually following a surgical procedure

What are the symptoms?

Commonly it starts with a boil around the anus – rarely the boil can be situated in a far away place like groin, abdomen & thigh. Uncommonly the boil can be inside the anus. The boil is very painful & the pain is relieved either when the boil ruptures spontaneously or when it is drained by a doctor. After the boil has ruptured or drained, the opening so formed keeps on discharging a yellowish fluid for some time. This may persist or the opening may close. In the later situation another boil may develop at the same site or another site. This episode may be repeated over a period of time. One can have multiple external openings too. The fistula tracts may spread & branch out over a period of time.

Do I need any special tests to diagnose it?

Majority of fistulas are diagnosed by the doctor after a detailed examination of the anal area. Only if the doctor is unable to come to a diagnosis or is not sure about the extent of the disease, he/ she may advice special tests for it. The tests commonly done are endoanal ultrasound or MRI. Fistulogram is another simple test, but provides limited information. It is not always necessary to do these tests & treatment may be offered without these tests. Usually all the fistula tracts are sent for histopathological examination after surgery.

Which doctor should I consult?

Most of the simple fistulas are treated by the general surgeon. The difficult fistulas are treated by specialists or colorectal surgeons. It is important to consult at least a general surgeon who will diagnose it & recommend a suitable line of treatment. A family physician may or may not be able to diagnose fistula in ano.

What is the treatment?

The acute stage of the disease – the abscess or the pocket of pus, is very painful & has to be surgically drained by a surgeon. This will give immense pain relief. Antibiotics are usually prescribed along with it. After draining the abscess, some patients may not require any further treatment as the whole disease process may get cured. In the rest the wound may not heal & may actually form the external opening of the fistula. These would require surgery for the fistula

Surgery for fistula in ano
There are various surgical procedures available for the treatment of fistula like fistulectomy, fistulotomy, coring out, seton, fibrin glue & anal fistula plug. The main aim of the surgery is to eradicate the disease along with the causative anal gland & keep the patient continent. The surgeon usually decides which procedure is most suitable depending on the type of fistula & his/ her past experience. The post operative dressings & wound care are as important as the surgery itself.

Can it recure?

On an average there may be a 10% chance of recurrence of a fistula after surgery. Experienced colorectal surgeons may have a 5% or lower rate of recurrence. Recurrence of a fistula depends on various factors ranging from the complexity of the fistula, the extent of the surgery, the post operative wound care & the experience of the surgeon.

Are there any complications of the surgery?

Recurrence is the major complication of surgery. Other significant complication includes inability to control the passing of faeces. This is not a common complication & can occur if the surgeon has cut the muscles responsible for the control of faeces. The incidence of this complication is very less if the surgery is done by an experienced colorectal surgeon. The cut muscles however can be stitched together & significant control can usually be achieved.