Skip to main content

Lateral Internal Sphincterotomy - the definitive fix for chronic anal fissure.

For chronic anal fissure that has stopped responding to GTN, diltiazem and Botox. A consultant colorectal surgeon, day-case, and a proper continence conversation before you consent.

See indicative pricing
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Indicative pricing

What lateral internal sphincterotomy costs privately in the UK.

Indicative ranges across our colorectal network.

In short

£2,800–£4,800, home the same day.

Procedure Indicative range
Colorectal consultation £250–£450
Botox injection for fissure £1,200–£2,200
Lateral internal sphincterotomy £2,800–£4,800
LIS + haemorrhoid banding £3,500–£5,800
Anorectal manometry £450–£800
Endoanal ultrasound £450–£850
Colonoscopy (if indicated) £1,600–£2,600

Prices vary by hospital, by the consultant and by whether medical trials were done privately or on NHS first. Combined procedures (e.g. fissure + haemorrhoid banding) sit at the top of the range.

The problem

The right ladder, the right sphincter, the right continence conversation.

LIS is one of the most effective operations in surgery. It also carries a real continence risk - which is why we insist on proper medical trials first and honest counselling before consent.

  • Try medical treatment properly first

    Not a two-week GTN dabble. Six to eight weeks at the right dose, then diltiazem and Botox as needed.

  • Divide only the internal sphincter

    Never the external. The internal is dividable; the external protects your continence.

  • A full continence conversation

    Small permanent minor incontinence risks exist. We put them in writing, before you sign, not after you wake up.

When it helps

When LIS is the right step.

The situations we see most, plus the red flag that means colonoscopy urgently, not a fissure operation.

  • Chronic anal fissure (over 6–8 weeks)

    A fissure that has failed to heal with proper medical treatment - the classic indication.

  • Fissure with skin tag or sphincter hypertrophy

    Chronic changes - sentinel pile, hypertrophied papilla, exposed sphincter fibres - that predict medical failure.

  • GTN or diltiazem intolerance

    Where headache or hypotension makes medical treatment impossible at effective doses.

  • Recurrent fissure after Botox

    Where Botox healed the fissure but it has returned - LIS gives durable healing where Botox does not.

  • Fissure with high resting anal pressure

    Where anorectal manometry confirms high pressure driving the fissure - LIS directly addresses the mechanism.

  • Multiple failed medical treatments

    Two or three failed medical courses justify surgery where continence risk is acceptable.

  • Preoperative continence concerns

    Where continence is already borderline, we do manometry and endoanal ultrasound first - sometimes Botox is safer than LIS.

  • Red flag: bleeding with change in bowel habit

    A fissure with weight loss, altered bowel habit or a family history of colorectal cancer needs colonoscopy first, not a fissure operation.

Alternatives

Not every fissure needs surgery - start higher up the ladder.

What each option involves, in the order most patients try them.

  • Conservative measures

    High-fibre diet, adequate fluid, stool softeners, sitz baths. Cures many acute fissures in 4–6 weeks.

  • Topical GTN (0.4% rectogesic)

    Reduces sphincter tone. Cures 40–60% at 6–8 weeks. Headache limits adherence.

  • Topical diltiazem (2%)

    Similar mechanism, fewer headaches. Cures 60–70% at 6–8 weeks. First-line in most UK centres.

  • Botox injection

    Weakens the internal sphincter chemically for 2–3 months, allowing healing. Cures 60–80% durably. Reasonable alternative to LIS in high-risk patients.

  • Lateral internal sphincterotomy (open)

    A small incision under direct vision divides the distal internal sphincter. 90–95% healing at 8 weeks.

  • Lateral internal sphincterotomy (closed)

    A percutaneous technique - same effect, no visible skin incision. Slightly higher rates of incomplete division.

  • Anal advancement flap

    Occasionally used for atypical or recurrent fissures where sphincter division is contraindicated - preserves continence.

  • Fissurectomy (rarely alone)

    Removes chronic tissue but without dividing sphincter - sometimes combined with Botox for the continence-averse.

Safety and recovery

What to expect afterwards - honestly.

LIS has one of the best success rates in colorectal surgery - 90–95% healing at 8 weeks. What we plan around is the small continence risk and the recovery.

  • GA or spinal in a proper day-case theatre

    Home the same day. Anaesthetic risks are low but real; someone must collect you.

  • Healing rate is excellent

    Around 90–95% of properly selected chronic fissures heal after LIS by 8 weeks - the best of any single treatment.

  • Minor incontinence risk is real

    Transient minor incontinence to gas and mucus in the first few weeks is common. Permanent minor incontinence occurs in 3–8% depending on series.

  • Permanent major incontinence is rare

    Under 1% in experienced hands with proper technique. We use tailored sphincterotomy (not full-length division) to minimise risk.

  • Higher risk in specific groups

    Women with previous vaginal deliveries, older patients and those with pre-existing continence issues need extra caution - Botox may be safer.

  • Bleeding and infection are uncommon

    Minor bleeding is expected in the first week. Significant bleeding, spreading infection or fever needs same-day review.

  • Perianal abscess or fistula are rare

    Uncommon (<2%) but recognised complications. Managed with prompt drainage and appropriate follow-up.

  • Failure to heal is uncommon

    Where LIS fails to heal, causes include incomplete division, missed distal disease, or Crohn’s. Repeat assessment with manometry and MRI where needed.

  • Red flags after surgery

    Heavy bleeding, spreading redness, high fever, inability to pass urine or severe unrelieved pain need same-day review.

Reading your notes

Your operation note in four parts. Read the last one first.

A short operation, but the note still has the same shape.

A UK consultant colorectal surgeon reviewing an operation note

A quiet reminder

Clinical language is precise - we translate it if you would like.

If you would like us to talk you through your notes before your review, just ask.

  1. 01 Header

    Indication and prior treatment

    Duration of fissure, medical treatments trialled and outcomes, and continence status pre-operatively.

  2. 02 Technique

    Approach and extent of division

    Open vs closed, side, extent of internal sphincter divided (typically dentate line to fissure apex - tailored).

  3. 03 Findings

    Fissure anatomy and other pathology

    Presence of sentinel pile, hypertrophied papilla, other haemorrhoidal or fissure pathology addressed.

  4. 04 Plan

    Aftercare and continence follow-up

    Read this first: fibre, softeners, sitz baths, return-to-work timeline, and the 3-month continence review.

Recognised by major UK insurers

BupaAXA HealthVitalityAvivaWPACignaHealixBupaAXA HealthVitalityAvivaWPACignaHealixBupaAXA HealthVitalityAvivaWPACignaHealix

Lateral internal sphincterotomy is usually covered when medically indicated and after failed medical treatment.

Frequently asked

Everything patients ask about LIS.

Quick answers on incontinence risk, healing, cost and cover.

  • Will LIS make me incontinent?

    The risk of transient minor flatal or mucus incontinence in the first weeks is real - perhaps 20–30% in the short term. Permanent minor incontinence sits at 3–8% depending on series, and permanent major incontinence at under 1% in experienced hands. Tailored sphincterotomy (not full-length) reduces risk. We test continence first if you have any pre-existing concern.

  • When should I try LIS instead of Botox?

    Botox first for lower-risk fissures and continence-anxious patients, and where a first medical trial has failed. LIS is preferred when Botox has failed at least once, when a durable single-shot solution is wanted, and when continence baseline is normal.

  • How much does LIS cost privately in the UK?

    Roughly £2,800–£4,800 as a day-case, or £3,500–£5,800 if combined with haemorrhoid banding. Botox alone runs £1,200–£2,200.

  • How long is recovery after LIS?

    Most patients are back to sedentary work in 3–5 days and to full activity in 2 weeks. The fissure heals over 6–8 weeks. Sitz baths, fibre and stool softeners are the mainstays - do not skip them.

  • Does the NHS offer LIS?

    Yes, though pathways vary. Some regions do a Botox trial as standard first line for chronic fissure; some proceed to LIS earlier. Private access is usually faster but should follow the same medical ladder.

  • Can the fissure come back?

    Recurrence after LIS is under 5% in the medium term. Where it recurs, causes include incomplete initial division, missed distal disease, or an underlying condition such as Crohn’s disease - which needs its own workup.

Related treatments

Looking for something else?