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Anorectal Fistula

(Fistula in Ano)

By

Parswa Ansari

, MD, Hofstra Northwell-Lenox Hill Hospital, New York

Last full review/revision Feb 2021| Content last modified Feb 2021
Click here for the Professional Version
Topic Resources

An anorectal fistula is an abnormal channel that leads from the anus or rectum usually to the skin near the anus but occasionally to another organ, such as the vagina.

  • Anorectal fistulas are common among people who have an anorectal abscess, Crohn disease, or tuberculosis.

  • Anorectal fistulas can cause pain and produce pus.

  • The diagnosis is based on an examination and other viewing techniques.

  • Treatment nearly always involves surgery, but some less invasive alternatives now exist.

The rectum is the section of the digestive tract above the anus where stool is held before it passes out of the body through the anus. The anus is the opening at the end of the digestive tract where stool leaves the body. (See also Overview of the Anus and Rectum Overview of the Anus and Rectum The anus is the opening at the end of the digestive tract where stool leaves the body. The rectum is the section of the digestive tract above the anus where stool is held before it passes out... read more .)

The Digestive System

Locating the Rectum and Anus

Fistulas that connect the rectum and vagina (called rectovaginal fistulas) may result from radiation therapy, cancer, Crohn disease, or an injury to a mother during childbirth.

Symptoms of Anorectal Fistula

An infected fistula may be painful and may discharge bloody pus.

Diagnosis of Anorectal Fistula

  • A doctor's evaluation

  • Sometimes anoscopy, sigmoidoscopy, or colonoscopy

A doctor can usually see one or more openings of a fistula or can feel the fistula beneath the surface.

A probe may be inserted to determine its depth and direction. By looking through an anoscope (a short, rigid tube) inserted into the rectum and exploring with the probe, the doctor may locate the internal opening of the fistula. Inspection with a sigmoidoscope (see Endoscopy Endoscopy Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). Endoscopy can also be used to treat many disorders because doctors are able to pass instruments... read more ), which is a much longer viewing scope, also helps the doctor locate the internal opening of the fistula and helps the doctor determine whether the problem is being caused by cancer, Crohn disease, or another disorder. Colonoscopy is done if the doctor suspects Crohn disease (see diagnosis of Crohn disease Diagnosis Crohn disease is an inflammatory bowel disease where chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both and may affect any part of the... read more Diagnosis ).

Treatment of Anorectal Fistula

  • Surgical procedures

  • For fistulas caused by Crohn disease, drugs

Previously, the only effective treatment was surgery to open the fistula (fistulotomy). During surgery, sometimes the sphincter is partially cut. If too much of the sphincter is cut, the person may have difficulty controlling bowel movements. Newer surgical procedures use advancement flaps (flaps are stretched over the opening of the fistula) or other procedures to close the fistula tract. Biologic plugs and fibrin glue instillations are alternatives to fistulotomy.

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