How is an anal fistula treated?

Written by: Professor Lee Dvorkin
Published: | Updated: 03/10/2023
Edited by: Conor Dunworth

Anal fistulas are a painful and distressing condition, and can cause persistent and troubling symptoms for the patient. In his latest online article, renowned colorectal surgeon Professor Lee Dvorkin explains this condition in detail. He offers his expert insight into the symptoms, causes and treatment of fistulas. 


What are anal fistulas?

An anal fistula is an abnormal connection from the anal canal (back passage) to the surface of the skin near the anus. 

Fistulas are not common, but they can cause significant distress for patients who have them. Symptoms include pain and the discharge of pus, blood or faeces from the skin openings. 

If a fistula develops into an abscess, symptoms may include: 

  • Pain
  • Swelling
  • Fever 

An abscess needs emergency surgery. 


How serious is a fistula?

Usually, patients with a fistula have persistent and troubling symptoms so, whilst it doesn’t not cause very serious problems, it can cause a real nuisance to patients and reduce their quality of life. Occasionally the fistula can develop into an abscess around the bottom. This causes severe pain and sepsis and will require emergency surgery to resolve it.


What’s the main causes of anal fistula?

Most patients (70-80%) do not have an underlying condition that causes the fistula. It arises because an infection develops around the anal muscles and within the anal glands which can become blocked.

For other patients, there are many other reasons  that can cause a fistula to develop. Pre-disposing causes include; Crohn's disease (where 30% of patients will develop a fistula), TB, HIV/AIDS, previous surgery or radiotherapy around the anus and rarely cancer of the rectum/anus.


Can a fistula heal by itself?

It is rare for a fistula to heal on its own.


How is it treated? Does it always require surgery?

Patients with a fistula should consult a colorectal surgeon with expertise in fistula surgery. They will carry out an examination to confirm the diagnosis and may request an MRI scan to get further information.

The treatment of anal fistulae will be different in each patient but will require surgery. All treatments aim to drain infection away, improve quality of life and, where possible, cure the fistula. If there is an underlying condition that caused the fistula, this will also need treating.

The type of operation suggested will depend on the location and severity of the fistula. With complex fistulas, more than one operation may be needed. With a simple fistula one of the most common operations is a fistulotomy.  In this, the infected tract is cut open. The wound created can take some time to heal but the success rate is 80-100%. Surgeons commonly don’t recommend this option in Crohn’s disease as there may be concerns about wound healing.

With complex fistulas which involve the anal sphincter muscle, there can be more of a risk of incontinence if the fistula is cut open.  So, the surgeon may put in a ‘seton’.  This is a thread which is passed through the fistula and out through the anus.

The most common type of seton is a loose seton.  This allows drainage of any infection and prevents abscesses forming. The seton may be removed later or can remain in place for some time.  Another option may be a ‘cutting seton’.  Here the seton is gradually tightened over time and this makes the seton ‘cheesewire’ slowly through the muscle closing the fistula as it moves.

Other treatment options for anal fistulas may include Collagen paste or plugs made of porcine (pig) tissue or laser treatment. These techniques are about 50% successful. Research is currently looking at injecting the fistula with stem cells, but more results are needed before this can be recommended routinely.

Professor Lee Dvorkin is a renowned consultant colorectal surgeon based in London, with over 25 years of experience. If you would like to book a consultation with Professor Dvorkin you can do so today via his Top Doctors profile.

By Professor Lee Dvorkin
Colorectal surgery

Professor Lee Dvorkin is a leading and well-respected consultant colorectal and general surgeon based in London.

Professor Dvorkin specialises in all aspects of benign and malignant bowel diseases including bowel cancer and inflammatory bowel disease. His clinical practice also includes the investigation and management of gastrointestinal problems, such as irritable bowel syndrome (IBS), inflammatory bowel disease, diverticular disease, abdominal pain and all common anal conditions (rectal bleeding, haemorrhoids, fissures and anal fistulae). He is formally accredited in colonoscopy and gastroscopy and undertakes laparoscopic (keyhole) surgery for gallstones, appendicitis, hernias and bowel cancer.
He practices privately at The Hospital of St John & St Elizabeth Hospital, The Wellington Hospital, The Hendon Hospital and The Cavell Hospital, while his NHS base is the North Middlesex University Hospital NHS Trust.
Professor Dvorkin holds an ​MBChB from the University of Leeds and the FRCS from the Royal College of Surgeons. He completed his basic surgical training in Wessex and after undertaking a period of research at The Royal London Hospital, was awarded his MD by the University of London. His research focused on pelvic floor disorders and has been presented both nationally and internationally. Professor Dvorkin continues with his surgical research and to publish numerous original works. 

Professor Dvorkin's higher surgical training took place in London and was completed in 2010. He then undertook an 12-month fellowship and a six-month laparoscopic colorectal fellowship at St Marks Hospital, which is internationally renowned for the treatment of bowel diseases.
He has held and continues to hold various senior academic and educational roles in the NHS and enjoys training the next generation of surgeons as director of an RCS Senior Clinical Fellowship programme. He is one of only a few colorectal surgeons in England to hold such a position, and he is also an honorary senior lecturer at University College Hospital. 

Professor Dvorkin is a member of various professional organisations including the Association of Coloproctology of Great Britain and Ireland (ACPGBI), the Royal College of Surgeons of England and the General Medical Council. 

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