Anal Fissure

Patient Information

What is an anal fissure?
A fissure is a split, tear or crack in the skin of the anal canal. This split fails to heal and forms a painful ulcer associated with spasm of the anal sphincter muscle.

Causes

Most anal fissures arise following trauma (injury) to the anus. The most common cause of anal fissures includes the passage of a hard, dry, constipated stool. However, anal fissures can occur following episodes of diarrhoea, childbirth etc. Anal fissures cause anal sphincter muscle spasms, and it is the spasms that causes the severe pain. The anal spasm decreases the blood supply to the anal fissure and slows down the healing process. The pain and spasm can lead to constipation and more tearing of the anal canal. This can become a vicious cycle and therefore prevents the healing of the anal fissure.

Symptoms

Pain is the main symptom of an anal fissure. Pain is described as a burning, sharp or stinging sensation that occurs during the passage of a bowel motion and may last for a variable period afterwards. The pain is due to tenderness of the fissure itself and the intense spasm of the internal anal sphincter muscle. Bleeding is a common symptom, especially when the fissure first develops and is usually fresh, bright red in colour and seen on wiping. Sometimes a swollen skin tag or lump develops at the external end of the fissure, and may be mistaken for a haemorrhoid.

Medical Treatment

Approximately 50% of anal fissures heal with non-operative (conservative) management. The ones that do not, become long term (chronic) fissures. Medical treatment includes ensuring soft stools by maintaining high dietary fibre, aperients, adequate fluid intake and careful anal hygiene to keep the fissure clean and dry. Frequent warm baths and topical application of muscle relaxing ointments (0.2% GTN or 2% diltiazem) help relax the anal sphincter muscle to reduce pain and help the fissure heal. These creams may cause headaches, so are best avoided in a history of migraines or recurrent headaches. Anal fissures may recur months or years later.

Surgical Treatment

Surgical treatment of an anal fissure can usually be performed as a day procedure with minimal hospital stay. The first surgical option includes injecting Botox® into the anal sphincter muscle space under a short general or spinal anaesthetic. Botox® is offered by some surgeons and Dr. Nagham provides this particular type of treatment. Botox® injection causes temporary relaxation of the sphincter and lasts 2-4 months giving time for the fissure to heal. It is a minimally painful procedure. Sometimes, a fissurectomy is done at the same time ( excision of the anal fissure) as the Botox® injection.

Persistent anal fissures may require a lateral sphincterotomy which involves a small cut near the anal opening, with the division of the lowest part of the internal anal sphincter muscle. The spasm is relieved, which helps the fissure to heal. Sometimes the fissure itself may be excised, together with any nearby haemorrhoids and any large or troublesome skin tags. The aim is to break the cycle of spasms, pain and constipation. This is usually done under a short general or spinal anaesthetic, and is also a day case procedure.

Results

There is usually rapid relief from the pain, even though healing of the fissure may take some weeks. Healing of the fissure is to be expected in 75-80% of those who have Botox® injection and 95% of those with sphincterotomy. Those with persisting symptoms may need a further procedure (Botox® injection or sphincterotomy). Post operative care includes keeping the stools soft and the anal area clean and dry.

Complications Of Surgery

These are very uncommon as the operation is relatively minor and safe. There may be postoperative bleeding or infection of the sphincterotomy wound. In approximately 5% of patients the healing of the wounds may be delayed.

Anal Sphincter Function After Surgery

Lateral sphincterotomy and Botox® injection may occasionally result in some difficulty of the control of “wind” in the rectum. This usually settles down within 3 months with Botox® injection but may be longer lasting following a sphincterotomy. Incontinence of faeces (loss of control of bowel movement) is an extremely rare complication.