At a glance
Lateral internal sphincterotomy (LIS) is a surgical procedure for chronic anal fissures that have not responded to other treatments. A surgeon makes a small, controlled cut in the internal sphincter muscle to reduce the spasm that prevents the fissure from healing.
This page covers what people commonly report about recovery — pain patterns, bowel movements, incontinence concerns, and when to seek care after the procedure.
What the procedure involves
LIS is typically a short procedure, often done under general or local anaesthesia. People commonly describe:
- The procedure itself lasting around 15 to 30 minutes
- Going home the same day in most cases
- A small wound at the side of the anus where the sphincter was cut
- Dressings that are minimal and straightforward to manage
Your surgeon will explain the specifics of your procedure and what to expect.
Recovery timeline
Recovery varies between individuals, but people commonly report this general pattern:
- Days 1 to 3 — soreness and swelling around the surgical site. Many people describe this as different from fissure pain — less sharp, more of a dull ache. Some people feel significant relief from fissure pain almost immediately.
- Days 4 to 14 — gradual improvement. Bowel movements may still be uncomfortable but people often report the intense fissure pain is gone or greatly reduced.
- Weeks 2 to 4 — most people feel substantially better. The surgical wound is healing. Many return to normal daily activities.
- Weeks 4 to 8 — full healing of the wound. Some people report occasional twinges or sensitivity during this period.
Pain patterns after surgery
People describe the post-surgical pain as notably different from chronic fissure pain:
- The sharp, tearing fissure pain often improves dramatically within the first few days
- Post-surgical soreness tends to be duller and more manageable
- Pain with bowel movements typically decreases significantly within the first week or two
- Some people report the first post-surgery bowel movement as nerve-wracking but less painful than expected
Bowel movement recovery
The first bowel movements after LIS are a common source of anxiety. People report:
- Keeping stools soft is essential — fiber, hydration, and stool softeners as discussed with your surgeon
- The first bowel movement often happens within 1 to 2 days after surgery
- Minor bleeding with bowel movements is common in the early days and tends to decrease
- The fear cycle often breaks after a few pain-free (or much-less-painful) bowel movements
Incontinence concerns
This is one of the most common worries people have before LIS. What people report:
- Minor gas control changes — some people notice reduced ability to hold gas, especially in the first few weeks. This usually improves over time.
- Occasional urgency — some people describe needing to reach a toilet more quickly than before, particularly early in recovery.
- Significant incontinence is uncommon — but it is a real risk that should be discussed with your surgeon before the procedure.
- Risk factors — people who have had previous anal surgeries, multiple pregnancies, or pre-existing sphincter weakness may have higher risk. Your surgeon can assess this.
What tends to help
- Following your surgeon’s post-operative instructions carefully
- Keeping stools soft with fiber and hydration from day one
- Sitz baths after bowel movements to soothe the area and keep it clean
- Taking prescribed pain relief as directed rather than waiting until pain is severe
- Giving yourself permission to rest during the first week
- Keeping a brief recovery journal to share with your surgeon at follow-up
What tends to make things worse
- Allowing stools to become hard during recovery
- Returning to strenuous activity too soon
- Skipping follow-up appointments
- Comparing your recovery timeline to others — individual variation is significant
- Ignoring new or worsening symptoms after initial improvement
Talking to your doctor
Before surgery, make sure you understand:
- Why LIS is being recommended for your case
- The specific risks, including incontinence
- What to expect during recovery
- When to call if something does not seem right
After surgery, contact your surgeon if you experience:
- Pain that is getting worse rather than better after the first few days
- Heavy bleeding or bleeding that increases over time
- Signs of infection — increasing redness, swelling, warmth, or discharge
- Fever
- Difficulty controlling bowel movements beyond what was discussed
If you experience severe pain, heavy bleeding, fever, or symptoms that concern you, seek medical care.