Anal Fistula

What is a Fistula?

A fistula is a small tunnel or an abnormal connection between two body parts, such as between an organ or bowel and another body part.

What is anal Fistula?

An anal fistula is a small abnormal tunnel that forms between an infected cavity or abscess in the anus to a skin opening around the anus connecting the two.

The anus is the body’s external opening through which the body expels feces.  Being the last part of the intestine, there are small glands inside the anus which makes up the mucus.  If these glands get clogged or blocked, it can cause infection, which leads to abscess.  If these abscesses are not treated, it will grow and it will eventually make its way outside creating a hole near the anus so that it can drain the fluid inside it.  This tunnel that connects the anus to the opening is called the fistula.

Causes of anal fistula

Anal glands that are clogged and abscesses in the anal canal are the main causes of anal fistula.

Other causes include:

• Crohn’s disease
• Diverticulitis
• Cancer
• Trauma

Symptoms of anal fistula

Some of the symptoms and signs of anal fistula includes:

• Pain
• Swelling around the anus
• Frequent anal abscesses
• Redness
• Skin irritation around the anal area
• Pain with bowel movements
• Bleeding
• Fever, chills, fatigue

How is anal fistula diagnosed?

The doctor examines the area around the anus looking for any opening on the surface, any drainage from the opening, and will try to determine how deep the fistula tract is, and the direction it is going. 

Sometimes, anoscopy is conducted, where a special instrument is used to visualize the anal canal and rectum.  MRI is ordered to better visualize the fistula tract.  The doctor might also order a colonoscopy to find out the status of the large intestine.

Treatment for anal fistula

The patient may need to undergo surgery for treatment of the anal fistula.  Some common procedures include:

Fistulotomy:  This procedure is used when there is little or no sphincter muscle involved.  The muscle over the tunnel is cut open in this procedure.

Advancement Flap procedure:  The fistula is covered with a flap that is taken from the rectum.      

LASER Treatment:  LASER for fistulectomy is also in good practice as the postoperative pain is very less.

In very complex cases diversion colostomy and staged procedures may be necessary.