Anal fissure repair surgery

What is an anal fissure?

An anal fissure is a tear or shallow ulcer in the lining of the anal canal, usually close to the opening of the anus. It is often painful and may or may not bleed. Fissures usually result from trauma to the anal canal—commonly from straining—and affect people of all ages, with a peak in children, young adults, and middle-aged people. If a fissure becomes chronic and does not heal, it can form extra scar tissue (sometimes called a sentinel pile or skin tag) that hangs near the opening. Do not self-diagnose or self-medicate; a proper examination is needed.

What causes anal fissures?

The main cause is strain that tears the skin around the anus. Contributing factors include:

• Reduced blood flow to the anorectal area.
• Straining from constipation or passing hard stools.
• Frequent diarrhoea.
• Pregnancy and straining during childbirth.
• Tightness or spasm of the ring of muscle (sphincter) that opens and closes the anus.
• Abnormal sphincter muscle function.
• Injury from scratching or wiping too forcefully.

Symptoms and diagnosis

Symptoms include blood on the stool or toilet paper, a visible crack or tear around the anus, constipation, burning and itching, sometimes frequent urination, and in some cases a smelly discharge. Diagnosis is by physical examination. The doctor may perform a digital rectal examination to check for other problems; in people aged 45 and over, a colonoscopy may be suggested to rule out other causes. It is important not to skip the examination out of embarrassment—getting the right diagnosis is the first step to effective treatment.

When is surgery recommended?

Many fissures improve with fibre, fluids, topical treatments (e.g. glyceryl trinitrate or calcium channel blocker ointments), and avoiding straining. When a fissure fails to heal and becomes chronic, or when symptoms are severe, surgery is the most effective and permanent option. A common operation is lateral internal sphincterotomy, which relaxes the anal sphincter to improve blood flow and allow the fissure to heal. We discuss the procedure, risks (including a small chance of affecting continence), and what to expect during recovery.

How to prevent anal fissures

Lifestyle changes and good habits can reduce the risk: drink plenty of water and healthy fluids; eat more fibre and consider a fibre supplement if needed; wipe gently after using the toilet; avoid straining when you pass stool; do not ignore the urge to open your bowels (holding it in can make stools harder and harder to pass); and aim for regular exercise (e.g. at least 150 minutes of physical activity per week). With treatment, many fissures heal within about six weeks.