Anal Fistula

What is a anal fistula ?

An anal fistula — also called fistula-in-ano — is an abnormal connection or tunnel that develops between the inside of the anus and the outside skin around the anus.

What causes anal fistulas ?

Most anal fistulas are the result of an infection that starts in an anal gland. The infection causes an abscess that drains on its own or is drained surgically through the skin next to the anus. This drainage tunnel remains open and connects the infected anal gland or the anal canal to a hole in the outside skin around the anus.

Very rarely anal fistula can be associated with other conditions like Crohn’s disease, Cancer, radiation therapy, Diverticular disease, Tuberculosis and Trauma

What are the symptoms of anal fistulas?

Symptoms of an anal fistula can include an opening or a wound on the skin around the anus that doesn’t heal. It can be after drainage of perianal abscess. It can be associated with Intermittent swelling, redness and pain. Patient also complains of oozing of pus, blood, gas or stool from the tunnel opening. Often patient develops recurrent perianal abscesses.

What are the types of fistulas ?

A fistula can be simple or complex depending upon underlying cause, amount of muscle involved and risk of incontinence.

They can be divided in to superficial, inter-sphincteric, trans-sphincteric, extra-sphincteric and supra-sphincteric based on relation to anal sphincter muscles.

How do we diagnose anal fistula?

Usually diagnosis is suspected from history and examination at the time of consultation in the office and confirmed after examination under anaesthesia (EUA) in operation theatre. In some complex cases MRI or Endoanal ultrasound can be required.

How do we treat anal fistulas?

There is no “one size fits all” option for treatment of an anal fistula. The treatment depends on the type of fistula, position of fistula, complexity, underlying cause and degree and risks the patient has of incontinence. The aim of the treatment are to repair the anal fistula completely to prevent recurrence and to preserve the continence by protecting the sphincter muscles. Damage to these muscles can lead to faecal incontinence.

Although surgery is usually required, sometimes nonsurgical treatments may be an option. Some anal fistula treatments can take a long period of time and be a difficult and frustrating condition for the patient. Healing rates are variable and sometimes multiple or staged operations can be required.

The options includes:

The initial treatment can be placement of seton (soft rubber band) for drainage of infection and allowing fistula tunnel to develop strong car tissues.

Fistulotomy involves cutting open the fistula tract and scraping and flushing out the infected tissue. This treatment is most appropriate for simple fistula where minimal amount of muscles are involved and there is no risk of faecal incontinence.

More complex fistulas or where fistulotomy cannot be performed may require complex procedures like mucosal advancement flap (MAF), Ligation of the inter-sphincteric fistula tract ( LIFT), Video assisted fistula treatment ( VAFT), Insertion of fistula plug and others.