At a glance
If you have a chronic anal fissure that has not healed with topical treatments, your doctor may discuss surgical options. The two most common procedures are fissurectomy and lateral internal sphincterotomy (LIS). They are different operations with different mechanisms, different risk profiles, and different trade-offs.
This guide is a clinical comparison to help you understand what each procedure does, how they differ, and what factors might make one more suitable than the other for your situation. It is not a recommendation — that conversation belongs with your surgeon, who knows your specific anatomy, history, and clinical picture.
We have separate guides covering what fissurectomy involves, LIS recovery, the combined procedure, and whether to have fissure surgery at all. This page focuses on the comparison between the two.
What each procedure does
LIS (lateral internal sphincterotomy)
LIS involves making a small, controlled cut in the internal anal sphincter muscle. The cut is typically made on the lateral (side) aspect of the sphincter, away from the fissure itself.
The purpose is to permanently reduce the resting pressure of the sphincter. High sphincter tone is central to why chronic fissures do not heal — the sustained spasm restricts blood flow to the fissure bed. By reducing this tone, LIS allows blood flow to improve and the fissure to heal.
Key characteristics:
- Targets the underlying cause (sphincter spasm) directly
- Creates a permanent reduction in sphincter pressure
- Small surgical wound, often internal
- Does not remove the fissure tissue — the fissure heals on its own once pressure is reduced
- Long track record with extensive published evidence
Fissurectomy
Fissurectomy involves excising the chronic fissure tissue, including any sentinel pile (skin tag) and scarred wound edges. The wound is left open to heal from the inside out.
The purpose is to remove tissue that has become too scarred and fibrotic to heal on its own, creating a fresh wound that the body can repair properly. It does not directly address sphincter spasm — which is why it is often combined with botox or, in some cases, a sphincterotomy.
Key characteristics:
- Targets the damaged tissue directly
- Does not cut the sphincter muscle (unless combined with sphincterotomy)
- Leaves an open wound that requires care during healing
- Removes sentinel pile and hypertrophied papilla
- Increasingly performed with botox to address sphincter spasm temporarily
The trade-offs
This is the core of the decision. Each procedure offers something the other does not, and each carries risks the other avoids.
Healing rates
LIS has the strongest published evidence for fissure healing. Large studies and meta-analyses consistently report healing rates in the range of 90 to 95 percent. It has been the gold standard surgical treatment for decades.
Fissurectomy alone has somewhat lower healing rates in most published studies — the fissure tissue is removed, but if the underlying sphincter spasm is not addressed, the wound can struggle to heal or the fissure can recur.
Fissurectomy with botox narrows the gap. The botox provides temporary sphincter relaxation during the critical healing window, and published series report healing rates that approach those of LIS. This combination has become increasingly popular, particularly among surgeons who want to avoid the permanent sphincter changes of LIS.
Incontinence risk
This is the factor that weighs most heavily on many people’s minds.
LIS involves a permanent cut to the internal sphincter. Published studies report varying rates of continence disturbance depending on how it is defined and measured — typically in the range of 5 to 15 percent for any change, with significant fecal incontinence much rarer. Most continence changes involve gas control rather than stool control, and many improve over time. But the change to the muscle is permanent.
Fissurectomy alone does not cut the sphincter. The risk of continence disturbance from the procedure itself is minimal.
Fissurectomy with botox may cause temporary gas control changes while the botox is active, but these resolve as the botox wears off over two to three months. There is no permanent change to the sphincter muscle.
This is the primary reason the fissurectomy-with-botox combination has gained popularity — it offers sphincter relaxation without a permanent structural change.
Recovery experience
LIS recovery typically involves less wound management. The sphincterotomy wound is small and often internal. Pain is generally moderate in the first week and settles relatively quickly. Many people describe a dramatic improvement in fissure pain within the first few days as the spasm is released.
Fissurectomy recovery involves managing an open wound. The wound can look alarming — it is intentionally left open and heals from the bottom up over four to eight weeks. Wound care (sitz baths, dressing changes, keeping the area clean) is a daily part of recovery. Some people find this more demanding than LIS recovery.
Both procedures have similar overall recovery timelines — most people are back to normal activities within two to four weeks, with full wound healing taking longer.
Recurrence risk
After LIS, fissure recurrence rates are low — the permanent reduction in sphincter tone continues to protect the area long after healing.
After fissurectomy alone, recurrence rates are somewhat higher because the sphincter spasm can return.
After fissurectomy with botox, recurrence depends partly on whether the underlying sphincter tone remains elevated after the botox wears off. Some people stay healed. Others may experience recurrence months later, potentially requiring further treatment.
What surgeons consider when recommending
Your surgeon’s recommendation will be based on several factors specific to you. Understanding what they are weighing can help you engage in the conversation:
Sphincter tone
If your resting sphincter pressure is very high — which can be assessed during examination — the case for addressing it directly (via LIS or botox) is stronger. Fissurectomy alone may be less likely to succeed if the sphincter tone remains very elevated.
Previous surgery or sphincter damage
People who have had previous anal surgery, multiple vaginal deliveries, or known sphincter weakness are generally steered away from LIS. The sphincter has less reserve to absorb a permanent cut. For these patients, fissurectomy with botox is often preferred.
The fissure tissue itself
If the fissure has become heavily scarred with a large sentinel pile and hypertrophied papilla, the damaged tissue may need to be removed regardless of what is done to the sphincter. In these cases, some element of fissurectomy is often appropriate — the question is what it is combined with.
Patient concern about incontinence
If you have significant anxiety about continence changes — or if your occupation or lifestyle makes any change in bowel control particularly problematic — this is a legitimate factor in the decision. Surgeons who understand this concern may lean toward fissurectomy with botox as the lower-risk option.
The surgeon’s own expertise and preference
Surgeons tend to recommend what they do well. A surgeon with extensive LIS experience and excellent outcomes may recommend LIS. A surgeon who has adopted the fissurectomy-with-botox approach and sees strong results may recommend that. Both recommendations can be reasonable. What matters is that the surgeon can articulate why they prefer their approach for your specific situation.
The combined approach
It is worth noting that fissurectomy and LIS are not always either/or. Some surgeons perform both together — fissurectomy with sphincterotomy — removing the chronic tissue and making a controlled sphincter cut in the same procedure.
This combined approach addresses both the damaged tissue and the underlying spasm. It may be recommended when the fissure tissue is heavily scarred and the sphincter tone is very high. The trade-off is that it combines the wound care demands of fissurectomy with the incontinence risk of sphincterotomy.
A decision framework
There is no universal right answer. But the decision often comes down to this:
Fissurectomy (with botox) may suit you if:
- You are particularly concerned about incontinence risk
- You have risk factors for continence problems (previous surgery, childbirth history, older age)
- Your fissure has significant chronic tissue (sentinel pile, scarring) that needs removing
- You are comfortable with the open wound care that recovery involves
- You accept the possibility that the fissure may recur if sphincter tone returns
LIS may suit you if:
- Your fissure is primarily driven by high sphincter tone
- You do not have significant risk factors for incontinence
- You want the approach with the longest track record and highest published healing rates
- The fissure tissue is not heavily scarred and does not need surgical removal
- You prioritise a lower recurrence rate over a lower incontinence risk
The combined approach may suit you if:
- You have both heavily scarred tissue and high sphincter tone
- Your surgeon recommends addressing both problems simultaneously
- You understand the combined risk profile
Questions to ask your surgeon
These are not confrontational questions. They are the questions that help you make an informed decision:
- Which procedure do you recommend for my specific situation, and why?
- What is your own experience with each approach — how many have you done, and what are your outcomes?
- What is the incontinence risk with the approach you recommend, based on your own patients?
- What is the recurrence rate you see?
- If the first procedure does not work, what are the next steps?
- Is there a reason not to try the less invasive option first?
A good surgeon will welcome these questions. The decision is ultimately yours, and having the information to make it is your right.
When to contact your doctor
After either procedure, seek medical attention if you experience:
- Heavy bleeding that is not slowing
- Worsening pain, particularly after the first few days when things should be improving
- Fever or signs of infection
- Difficulty with bowel control — any new changes should be reported, even if they seem minor
- Any symptom that concerns you
If you are in the decision-making phase and feeling overwhelmed, remember that this is a conversation — not an exam. Your surgeon is there to help you understand your options, not to judge your questions. Take the time you need.