What is a Fistula?

A fistula is an abnormal connection between intestine, vessel or organ, and another structure. Anal fistula is a small channel that develops between the end of the bowel, called the anal canal, and the skin near the anal opening. The end of the channel appears as a hole on the skin near the anus, and can cause severe pain and bleeding while passing bowel movements.

Causes of Fistula

Perianal fistula usually results from perianal abscess (painful collection of pus). The condition may also develop as a complication of surgery, abnormal growths, ulcers, congenital abnormality, or may be associated with certain conditions including TB, HIV/AIDS, sexually transmitted diseases (syphilis, chlamydia), rectal cancer, diverticulitis, ulcerative colitis, and Crohn's disease.

Symptoms of Fistula

A fistula can cause pain, swelling and tenderness around the anus. You may also experience discharge of pus or blood when passing stools, causing irritation and itching of the skin. Other symptoms include abdominal pain, diarrhoea, fatigue, fever and chills.

Diagnosis of Fistula

Dr Krishnan may diagnose the condition by reviewing your medical history and physical examination. Rectal exam is performed by inserting a lubricated finger into the rectum. A proctoscope, a lighted telescope may be inserted to examine the rectum. Additionally, special imaging tests such as X-rays, CT scan, MRI and ultrasound may be needed if the condition is complicated.

Treatments for Fistula

It is very rare that the problem resolves on its own. Injection of fibrin glue, a solution of fibrinogen and thrombin, may be used to close the anal fistula as a non-surgical procedure, but has not shown good prognosis.

Surgical Treatments for Fistula

Surgery is usually the first line of treatment. It aims at healing the fistula without damaging sphincter muscles that control the opening of the anus. Surgery will depend on the location of the fistula. Some of the procedures may include:


The most common treatment for an anal fistula is an operation called fistulotomy. The procedure involves opening the fistula along the entire length, flushing out the contents and flattening it out. The fistula will heal into a flat scar in a month or two. Your surgeon may cut a small part of the sphincter muscle in order to access the fistula.

Advancement Flap Procedure

For complex fistulas an advancement flap procedure is considered. It usually follows a fistulotomy and involves the removal of a portion or flap of the rectal wall or anus and then attaching it to the internal opening from where the fistula was removed.


For deeper fistulas a seton, a piece of surgical string, is placed along the fistula tract to keep it open. This allows for proper drainage before it heals. It may be used for secondary tract fistulas.

Bioprosthetic Plug

A cone-shaped plug made from tissue is placed to block the internal opening of the fistula. Stiches keep the cone in place but it is not sealed completely, allowing the fistula to drain. New tissue grows around the plug, healing it.