Lateral anal sphincterotomy

Lateral anal sphincterotomy is an operation to treat an anal fissure. An anal fissure is a tear or split in the skin lining of the anus, just inside the back passage.

Printable Patient Information Leaflet

Patient Information leaflet (585kB)

Is the operation necessary?

Sometimes an anal fissure will not heal, even if you are using the medicated creams and stool softeners recommended by your doctor. You may continue to have uncomfortable symptoms. If this is the case, surgery can help. Your surgeon will discuss this choice with you.


What happens during the operation?

The operation is often done under a general anaesthetic. This means you will be asleep during the procedure and will feel no pain. Your surgeon will first make a small cut in the skin of your anal canal (back passage) to reach the anal sphincter (the muscle around your anal canal). This ring of muscle controls the opening and closing of the anus. The surgeon will then make a small cut in the sphincter to relax it and stop it going into spasm. This will allow the fissure to heal.

The small skin wound may be stitched or left open to heal naturally. Afterwards a pad or dressing will be put onto your anus to help stop the bleeding. Usually you will feel well enough to return home the same day, but sometimes you may need to stay in hospital overnight.


Are there any risks associated with cutting the sphincter muscle?

The cut in the sphincter muscle should not mean that the anus opens too easily, but very rarely the cut may affect your ability to control your bladder and bowels. The effects are usually minor and do not need to be treated.

If the sphincter muscle is damaged during the operation, you may need to have more surgery to correct the problem. This is very rare.


What can I expect after my operation?

You will have some discomfort after the operation. This can be eased using simple pain relievers which you will be given to take home when you leave hospital. You should have a bath the day after your operation – this will help to soak away any dressing. You may bleed a little in the bath. It is important to keep the anus area clean.

For the first few days after your operation try to take a bath or shower, or use the bidet (if you have one), after each time you open your bowels. Once the first few days have passed and you are back to normal activities, you can wipe your anal area using damp cotton wool. You may see a little blood with your stools (poo) or on the toilet paper, usually for seven to 10 days after the operation. If you are a woman, you should remember to wipe the anus area from front to back, away from the vagina.

It will be more comfortable for you to go to the toilet if the stool is soft. Make sure you drink plenty of fluids and eat a high-fibre diet (containing things like vegetables, pulses and bran). You may be given a stool softener (a laxative that makes your stools softer) to take home from hospital.

There may be a small amount of mucous discharge (slime) from your back passage for a few days after the operation. A small pad or panty liner will prevent stains on your underwear. Cotton underwear will be most comfortable.


When can I return to work?

The recovery time will vary but you should feel well enough to return to work after a few days.
If, after you leave hospital, you have any new concerns or problems (for example, severe pain around the anus, a raised temperature or bleeding from the anus) you must contact your own doctor (GP) or the hospital. You will be given contact numbers in case this happens.