A Focus on Anal Fistulas

Posted on Healthcare By Dr. Matthew Tytherleigh - FRCS - Published on 2014-12-15


What are anal fistulas?
An anal fistula is a track between the skin on the outside of the buttock/anal area and the anal canal on the inside. There are many different types of fistulas. They can be simple or complex, depending on whether there is a single fistula tract or multiple interlinking connections. Fistulas may be low or high, depending on its position and how close it is to the sphincter muscle, which opens and closes the anus and controls continence.

What are the common symptom and signs?
Recurrent perianal abscesses are very likely to be due to an underlying fistula. There may be pain and swelling around the anus. Discharge of blood and pus from an opening near the anus often improves the pain. The skin around the anus becomes irritated and sore due to the persistent discharge.

What is the cause of an anal fistula?
A fistula is the end result of a perianal abscess. An abscess results from an acute infection of a small gland just inside the anus, when bacteria or foreign matter enters the tissue through the gland. Certain conditions, such as diabetes or Crohn's disease, can sometimes make these infections more likely. Approximately 50% of perianal abscesses develop into a fistula. Rarely, fistulas can result from other diseases such as tuberculosis, diverticulitis or cancer.

How are anal fistulas diagnosed?
The simplest way to diagnose these problems is an examination by a colorectal surgeon who deals with this condition. Digital rectal examination, together with proctoscopy and sigmoidoscopy (simple telescope test to look into the rectum) are used to confirm the diagnosis. An MRI scan is used to define the exact location of the fistula and its relationship to the sphincter muscles.

What is the treatment for anal fistulas?
Surgery is necessary to treat anal fistulas and the type of surgery will depend on the location of the fistula. The aim of surgery is to heal the fistula while avoiding any damage to the sphincter muscle. Damage to the muscle can lead to incontinence. Simple, low fistulas that do not involve the sphincter muscle can be treated by fistulotomy, where the fistula is cut open, cleaned and allowed to heal. Complex fistulas and fistulas that pass through the sphincter muscle are initially treated by inserting a surgical thread or seton through the fistula. This keeps the tract open and prevents further abscesses forming. It is left in for a number of months. During this time, the body reacts to the seton and pushes it out, so that at a further operation the seton can be removed by just dividing the skin. Occasionally, fistulas need to be treated with fibrin glue or bio-prosthetic plugs. The LIFT procedure (Ligation of Intersphincteric Fistula Tract) is a relatively new operation that is also used for complex fistulas.


About Author

Dr. Matthew Tytherleigh - FRCS

Dr. Matthew Tytherleigh is a consultant general surgeon. He was trained at St. Bartholomew's Hospital in London, UK. Dr. Tytherleigh's surgical training was at John Radcliffe Hospital, Oxford with Professor Neil Mortenson. In 2006, he was awarded the Fellowship of the Royal College of Surgeons of England (General Surgery). His research was undertaken at the Weatherall Institute of Molecular Medicine, Oxford with Professor Sir Walter Bodmer. Dr. Tytherleigh spent his Colorectal Fellowship year with Professor Les Bokey at Concord Hospital in Sydney, Australia. Following completion of his training, Dr. Tytherleigh was appointed as a locum Consultant Colorectal Surgeon at Addenbrooke's Hospital, Cambridge and subsequently, to a substantive post at Ipswich Hospital. Dr. Tytherleigh has been instrumental in improving guest safety, clinical governance issues and has implemented a number of initiatives including an enhanced recovery program. In 2011, he gained a Clinical Excellence Award for this work. Dr. Tytherleigh specializes in colorectal cancer, laparoscopic (keyhole) surgery, inflammatory bowel disease and colitis, proctology (such as hemorrhoids, fissures and fistulas), fecal incontinence, prolapse, hernia surgery and advanced colonoscopy. To his credit, he has co-authored the Colorectal Surgery chapter in The New Aird's Companion in Surgical Studies, the recommended UK surgical trainee textbook.

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