A guide to anal fistulas

Written by: Mr Tushar Agarwal
Edited by: Conor Dunworth

Anal fistulas are painful tunnels running from within the anal passage to an opening on the skin outside. In his latest article, consultant colorectal surgeon Mr Tushar Agarwal shares his expert insight into the condition.  


What is an anal fistula?

Anal fistulas are abnormal communication from an opening inside the rectum to an opening on the skin. There is a tract joining the two openings together.


How do they form?

In the majority of cases, we don’t know why they form. Some people have underlying conditions such as Crohn’s disease that can make them more susceptible to getting an anal fistula.

In the majority of cases, fistulas form following the appearance of an abscess.


Can they be prevented?

Unfortunately, fistulas cannot really be prevented. They form and must be treated, and there is not much you can do to stop them from happening.


How are fistulas diagnosed?

The diagnosis is usually made clinically. After a clinical examination, you can have a fairly good idea if it is a fistula or not. The next investigation is an MRI scan. This not only confirms the fistula but can give us an idea of what type of fistula you have. It could be a low fistula or a high fistula, and these are treated differently.


What does an anal fistula treatment entail? When is surgery required?

If the fistula is symptomatic, then it needs to be treated. There are no medicines that will treat a fistula, so surgery is required. There are various surgical options depending on the type of fistula. Surgery usually involves opening up the fistula, and sometimes a stitch around it.

There are new techniques that have been introduced recently, which involve laser treatments. There are also more complex procedures, such as flaps or suturing of the fistula tract. The treatment depends on the type of fistula ascertained by a clinical examination and an MRI scan.


Mr Tushar Agarwal is a leading consultant colorectal surgeon based in London, with over 30 years of experience. If you would like to book an appointment with Mr Agarwal, you can do so today via his Top Doctors profile.

By Mr Tushar Agarwal
Colorectal surgery

Mr Tushar Agarwal is currently working as a colorectal surgeon at St. Marks Hospital, London. He qualified from the University of Delhi, India, and completed his initial postgraduate training in surgery from the University of Delhi.

After moving to the United Kingdom, he completed his higher surgical training from the North West Thames Surgical Rotation. He was awarded an FRCS (Intercollegiate) in 2008, and his speciality training focused on colorectal surgery.

Mr Agarwal subsequently completed a one-year fellowship in colorectal surgery at the University College Hospital and Guys & St. Thomas’ Hospital. He also undertook a period of observership at the Colorectal Unit at Cleveland Clinic in Ohio and at the Trauma unit of Charlotte Maxeke Hospital in Johannesburg, South Africa. Mr Agarwal, who was appointed as a consultant surgeon in 2011, initially joined Chelsea & Westminster Hospital as a locum consultant and was subsequently appointed as a substantive consultant at the London North-West NHS Trust as a colorectal surgeon.

Mr Agarwal specialises in colorectal cancers and carries out cancer operations both laparoscopically and openly. He routinely performs proctology procedures (surgery for haemorrhoids, anal fissures and anal fistulae), pilonidal sinus surgery and general surgical procedures such as hernia repairs. Mr Agarwal is a JAG-approved endoscopist and carries out diagnostic upper GI endoscopies and colonoscopies.

He is a recognised endoscopy trainer and routinely trains surgical trainees in endoscopy. He is committed to undergraduate and postgraduate surgical education and is an honorary senior lecturer at Imperial College, London. He is a training programme director for foundation year trainees.

He is so too a consultant trainer at the London Deanery Skills Lab and a recognised consultant trainer for higher surgical trainees in the London North-West Deanery. He is an examiner for the PLAB exam conducted by the General Medical Council for overseas doctors, and is a panel examiner for Imperial College for medical student entrance exams. Outside surgery, Mr Agarwal is an ECB-qualified cricket umpire. He regularly tutors on courses for cricket umpires in Middlesex and has recently been appointed the women’s umpires development officer for Middlesex.

View Profile

Overall assessment of their patients

  • Related procedures
  • Gastroscopy
    Pelvic floor reconstructive surgery
    Robotic surgery
    Rectal surgery
    Anal fistula surgery
    This website uses our own and third-party Cookies to compile information with the aim of improving our services, to show you advertising related to your preferences as well analysing your browsing habits. You can change your settings HERE.