At a glance
Lateral internal sphincterotomy (LIS) is the most effective surgical treatment for chronic anal fissures. The decision to have it often comes after conservative treatments and botox have been tried. This guide covers the practical preparation, the day of surgery, and the immediate aftermath.
Before surgery
The weeks before
Once the decision for surgery is made, most surgeons recommend:
- Starting stool softeners — three to five days before surgery. Soft stools after surgery make the first bowel movements more manageable.
- Stocking up on supplies — sitz bath basin, soft towels, comfortable loose clothing, stool softeners, pain medication, soft foods
- Arranging time off — most people take one to two weeks off work, though some return sooner
- Asking questions — this is the time to clarify anything you are unsure about with your surgeon
The day before
- Light meals
- Continue stool softeners
- Follow any fasting instructions from the hospital (typically nothing to eat or drink after midnight)
- Prepare your recovery space at home
- Try to rest, even if anxiety makes this difficult
The day of surgery
Arriving
You arrive at the hospital or day surgery unit. People describe a mix of anxiety and relief — relief that after months of conservative treatment, something definitive is happening.
Standard pre-surgery steps:
- Check-in and paperwork
- Meeting the anaesthetist
- Changing into a hospital gown
- Final questions with the surgeon
The procedure
LIS is a brief procedure:
- You are given anaesthesia (general or regional)
- The surgeon makes a small cut in the internal sphincter muscle
- Some surgeons also remove any sentinel pile (skin tag) at the same time
- The procedure takes 15 to 30 minutes
- You wake up in recovery
Waking up
People describe waking up and feeling surprisingly okay. The area may be numb from local anaesthesia applied during the procedure. There is often gauze or a dressing in place.
Common first thoughts:
- “That was it?”
- “I feel fine — is it actually done?”
- “When can I go home?”
Going home
Most people go home the same day, within a few hours of the procedure. Arrangements for someone to drive you home are essential — you cannot drive after anaesthesia.
The first 24 hours
The local anaesthetic wears off within hours. This is when the surgical discomfort becomes apparent. People describe:
- A dull ache or throbbing in the area — different from fissure pain
- The first bowel movement as a source of significant anxiety
- Mild bleeding or discharge on the dressing
- Tiredness from the anaesthesia
Self-care in the first 24 hours:
- Take prescribed pain medication as directed
- Sitz baths — start as soon as you are comfortable enough
- Drink plenty of water
- Eat soft, fibre-rich foods
- Rest — this is not the day for activity
The first week
The first week after LIS is covered in detail in our LIS surgery recovery guide and our week-by-week recovery experience.
The headline: the first week is the hardest. It gets significantly better from there.