Lateral sphincterotomy is an operation to treat a chronic anal fissure that has not responded to conservative therapies. The procedure is performed under a short general anaesthetic (10 – 15 minutes) and is done as a day case. A 5-10mm incision is made at the anal verge usually on the left side. The internal anal sphincter is exposed and small amount of the muscle is cut (approx. 5mm). The wound is left open to heal. The fissure is sometimes debrided and tags and scar tissue can be removed. Local anaesthetic is injected into the wounds. Lateral sphincterotomy is a highly successful operation with a success rate of > 96% with a low recurrence rate.
What to expect post-operatively
The fissure wound and the sphincterotomy wound will take up to 4 – 6 weeks to completely heal.
Local anaesthetic will be injected into the wound at the end of the operation and therefore you should be comfortable when you wake up. There will be discomfort in the perianal region for the first few days. The severe fissure pain usually resolves within 1 – 3 days but occasionally some chronic fissures take longer to feel more comfortable. You should take regular analgesia in the first 48 hours including paracetamol (Panadol) 1g (2 tabs) every 4-6 hours (max 8 tabs per day) and an anti-inflammatory such as ibuprofen (nurofen) 400mg every 4 – 6 hours with food. Occasionally, stronger pain-killers such as tramadol and endone are needed. After 48 hours, use the painkillers only if needed.
Most commonly, no dressings are needed in the wound and a simple sanitary pad should be worn in the under wear to collect any discharge. Discharge from the wounds is expected and can last for weeks. This is normal. The discharge can be blood stained and/or pus like. Keep the wound clean by showering with soap and water or by taking a salt bath (add table salt to a warm bath), pat the wound dry and replace the sanitary pad.
Keeping the stool soft is very important. Use either movicol 1-2 sachets daily or Metamucil 1-2 sachets daily (especially if using endone). Try not to strain.
You can return to work and exercise when you feel comfortable. This may be a couple of days for some people and some weeks for others.
Complications are unusual.