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Botox vs LIS surgery for fissure

Published 13 March 2026 ·Last reviewed 13 March 2026 by the editorial team ·How we create our content

At a glance

For people with a chronic anal fissure that has not responded to conservative treatment, the two main procedural options are botox injection and lateral internal sphincterotomy (LIS). Both aim to relax the internal sphincter muscle to break the fissure-spasm cycle and allow healing.

They differ significantly in approach, success rate, risk profile, and reversibility. This guide compares them clearly to help you understand the trade-offs before discussing with your surgeon.

How each procedure works

Botox

Botulinum toxin is injected into the internal sphincter muscle, temporarily paralysing it. This relaxes the spasm, increases blood flow to the fissure, and creates a window for healing. The effect lasts two to four months, after which the muscle returns to normal function.

LIS (lateral internal sphincterotomy)

A small portion of the internal sphincter muscle is surgically divided (cut). This permanently reduces the resting pressure of the sphincter, breaking the spasm cycle and allowing the fissure to heal. The effect is permanent.

The comparison

Success rate

LIS: approximately 90 to 95 percent for chronic fissure healing. It is the most effective surgical treatment available.

Botox: approximately 50 to 80 percent, depending on the study and definition of success. Some people heal completely. Others experience partial improvement. Some do not respond.

Reversibility

LIS: permanent. The muscle that is divided does not regrow. This is a one-way decision.

Botox: temporary. The effect wears off in two to four months. If there are unwanted effects, they resolve on their own.

Continence risk

LIS: there is a small but real risk of minor continence changes — most commonly difficulty controlling gas. The risk of significant faecal incontinence is very low but not zero. This risk is permanent.

Botox: temporary continence changes are possible while the botox is active but resolve as the effect wears off. This temporary nature makes botox lower-risk from a continence perspective.

Recovery

LIS: a surgical procedure requiring anaesthesia, typically as a day case. Recovery takes two to four weeks for most people, with pain during the first week.

Botox: a brief injection, sometimes done under sedation, sometimes in clinic. Recovery is minimal — most people return to normal activities within a day or two.

Pain

LIS: post-operative pain for several days to a week, though many people describe it as less severe than the chronic fissure pain they were living with.

Botox: the injection itself causes minimal pain. Post-procedure discomfort is typically slight.

Recurrence

LIS: recurrence rates are low — the permanent sphincter modification makes re-tearing less likely.

Botox: recurrence is more common, as the sphincter returns to its normal pressure once the botox wears off. Some people need a second injection or proceed to LIS.

How people typically decide

The decision between botox and LIS often follows a pattern:

Try botox first

Many clinicians recommend botox as a first step because:

  • It is less invasive
  • It is reversible
  • If it works, the fissure heals without permanent sphincter modification
  • If it does not work, LIS remains available

Go directly to LIS

Some clinicians recommend LIS directly when:

  • The fissure is severe and longstanding
  • Conservative treatment and topical therapies have already failed
  • The patient prefers a single, definitive procedure
  • The anatomy and sphincter assessment suggest low continence risk

Factors that influence the choice

  • How long the fissure has been chronic — longer-standing fissures may be less likely to respond to botox alone
  • Sphincter pressure — very high resting pressure may respond better to LIS
  • Continence concerns — people with any existing continence issues may prefer the reversible option
  • Personal preference — some people want to try the least invasive option first; others want the highest chance of resolution

The honest picture

Neither option is perfect.

Botox offers safety and reversibility at the cost of a lower success rate and the possibility of needing further treatment.

LIS offers the highest success rate at the cost of a permanent change to the sphincter and a small but non-zero risk of continence change.

Most people who go through this decision describe it as genuinely difficult. There is no obviously right answer — it depends on your specific situation, your risk tolerance, and your priorities. This is a conversation to have thoroughly with your surgeon, who can assess your fissure, your sphincter, and your individual risk profile.

Common questions

Which has a higher success rate — botox or LIS?

LIS has a higher success rate for chronic fissure healing, generally reported in the range of 90 to 95 percent. Botox success rates are lower, typically 50 to 80 percent depending on the study and the definition of success. However, botox is reversible and carries less risk, which is why it is often tried first.

Is botox always tried before LIS?

Not always, but it is a common pathway. Many clinicians recommend trying botox first because it is less invasive and reversible. If botox does not work or the fissure recurs, LIS is then considered. Some clinicians may recommend going directly to LIS for certain patients, particularly those with severe, longstanding fissures.

What is the continence risk with each?

Both procedures carry some risk of temporary changes to gas control. For botox, this is temporary by nature — the botox wears off. For LIS, any continence change is potentially permanent because the sphincter is physically divided. The risk with LIS is generally low and relates mainly to minor gas incontinence, but it is not zero.

Can I have botox more than once?

Yes. Some people have a second botox injection if the first was partially effective or if the fissure recurs after initial healing. There is no strict limit, though the decision to repeat versus move to surgery is made on a case-by-case basis.

How long does botox last?

The muscle-relaxing effect of botox typically lasts two to four months. During this window, the fissure has the opportunity to heal. Once the botox wears off, the sphincter returns to its normal tone. If the fissure has healed during that window, the benefit is permanent.

When to seek care Heavy bleeding or feeling faint? Get emergency help now. Emergency: 911

Not sure how urgent it is? Get help today.

  1. Emergency

    Heavy bleeding, black tarry stools, feeling faint, severe pain or trouble breathing.

    Call 911 or go to the ER.

  2. Today

    Fever, pain getting worse, a hot swollen lump, or trouble passing urine.

    Call your doctor or go to urgent care.

  3. Soon

    Bleeding or bowel changes nobody has checked, or anything lasting 3 weeks.

    Book a doctor’s appointment.

Feeling overwhelmed? Call or text 988, any time.

See all the signs

For this topic, get medical advice if you notice:

  • Bleeding that is heavy or will not stop
  • Severe pain that is getting worse
  • Difficulty controlling gas or bowel movements
  • Fever or signs of infection

Recording how you feel is not the same as being checked. These are the signs that need a doctor’s attention.

Call 911 or go to the emergency room now if you have:

  • bleeding that will not stop, a lot of blood (the toilet water turns red, or you pass large clots), or any bleeding with feeling faint or dizzy
  • fainting, a racing heart or trouble breathing
  • confusion or slurred speech, extreme shivering, no urine in a day, or blotchy skin
  • sudden severe belly pain, or a swollen, hard belly with vomiting or not passing stool or gas
  • you cannot pass urine at all, or your bladder feels full and painful and you can’t empty it
  • redness, swelling or severe pain spreading quickly around your anus, genitals or groin, especially with a fever or feeling very ill
  • a fever with a painful swelling near your anus if you have diabetes or a weakened immune system (for example, from chemotherapy or transplant medicines)
  • black, tarry stools

Call your doctor or go to urgent care today (or the ER if you can’t be seen today) if you have:

  • a temperature of 100.4°F (38°C) or higher, chills, vomiting, or feeling generally unwell
  • pain that is getting worse over days, or severe pain that stops you sitting or sleeping
  • a hot, swollen or very tender lump near your anus or at the top of the crease between your buttocks, or foul-smelling discharge
  • trouble urinating
  • bleeding that is getting heavier or more frequent, or blood mixed into your stool
  • feeling much more tired than usual, looking pale, or getting out of breath more easily than you used to
  • not passing stool for several days, or new belly pain

Make an appointment with your doctor if:

  • you have never had these symptoms checked by a doctor or nurse — whatever your age
  • you have had rectal bleeding for more than 3 weeks
  • your bowel movements have been looser, thinner or more frequent than usual for 3 weeks or more, or you have lost weight without trying
  • symptoms have not settled after a week or so, or keep coming back
  • you notice a new lump near your anus, between your buttocks or in your belly, or an itch or discharge that does not clear
  • you have new leakage or trouble controlling your bowels
  • you are 45 or over, or have a family history of bowel cancer or inflammatory bowel disease, and any of these symptoms are new for you

If you are unsure, it is always reasonable to ask. If things feel overwhelming, call or text 988 (Suicide & Crisis Lifeline) or chat at 988lifeline.org, any time. If you don’t feel safe, call 911.

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Related symptoms

BleedingPain during bowel movementsPain after bowel movementsSpasm or crampingConstipation

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Related guides

Botox for fissure: what people report

What botox treatment for chronic anal fissure involves, what people report about the procedure and recovery, effectiveness patterns.

Recovery after LIS surgery

What to expect during recovery from lateral internal sphincterotomy (LIS) for chronic anal fissure — pain patterns, bowel movement recovery.

Thinking about fissure surgery

A framework for weighing surgical options for a chronic fissure — the questions to ask, the factors to consider.

Related experiences

Fissure botox vs LIS surgery

The decision journey between botox and LIS for a chronic fissure — people who tried botox first, what happened, and why some moved to surgery.

LIS surgery: the full journey

The full emotional arc of lateral internal sphincterotomy — from failed conservative treatment through the decision, the NHS wait, the day itself.

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