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FiLaC laser treatment for fistula

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

At a glance

FiLaC — fistula laser closure — is a newer, minimally invasive option for treating anal fistulas. It uses a laser fibre to seal the fistula tract from the inside, with the goal of closing the tract while preserving the sphincter muscle.

It is not the right option for every fistula, and the evidence base is still developing. But for certain types of fistulas, particularly in people where sphincter preservation is a priority, it is an option worth understanding.

How it works

The FiLaC procedure involves:

  1. Identifying the fistula tract — usually done under anaesthesia with a probe
  2. Inserting a radial laser fibre into the tract from the external opening
  3. Activating the laser — the fibre emits energy in a 360-degree pattern, destroying the lining of the tract
  4. The internal opening is closed — typically with stitches or a small flap
  5. The tract is left to heal from the inside out

The key advantage is that the laser targets the tract itself without cutting through surrounding tissue, including the sphincter muscle.

Who it may be suitable for

FiLaC tends to be considered for:

  • Simple or transsphincteric fistulas where preserving sphincter function is important
  • People who have had previous fistula surgery and want to avoid further sphincter involvement
  • Cases where incontinence risk from traditional surgery is a significant concern
  • People who prefer a less invasive approach and accept a potentially lower success rate in exchange

It is generally less suitable for:

  • Very complex or branching fistulas
  • Fistulas with active, undrained abscess
  • Situations where the internal opening cannot be clearly identified

What people describe about recovery

Recovery from FiLaC is commonly described as easier than recovery from open fistula surgery:

  • Less pain than fistulotomy — many people describe manageable discomfort rather than significant pain
  • Some drainage in the first week or two — this is expected as the tract heals
  • Quicker return to daily activities — often within one to two weeks
  • Less wound care than open surgery, since there is no large external wound

The main concern people describe during recovery is uncertainty about whether the tract has fully closed. Follow-up appointments and sometimes imaging help confirm healing.

How it compares to other options

FactorFiLaCFistulotomySetonAdvancement flap
Sphincter sparingYesDepends on fistulaYes (staged)Yes
Success rate50-70%85-95%High (staged)60-80%
Recovery time1-2 weeks4-8 weeksVaries4-6 weeks
Pain levelLowerHigherModerateModerate
Repeat proceduresMay needRarelyBy designMay need

These are general patterns. Individual outcomes depend on the specific fistula, the surgeon’s experience, and many other factors.

Questions to ask your surgeon

If FiLaC is being discussed as an option for you:

  • How many FiLaC procedures have you performed?
  • What has your personal success rate been?
  • Is my fistula type suitable for this approach?
  • What happens if the FiLaC does not work — what is the next step?
  • Is this available on the NHS or is it private only?

The evidence picture

FiLaC is a relatively newer technique, and the evidence base is still growing. Early studies show promising results for simple fistulas, but long-term data and large randomised trials are limited compared to established procedures like fistulotomy. This does not mean it is ineffective — it means the evidence is still maturing.

Your surgeon is the best person to help you weigh the evidence against your specific situation.

Common questions

What does FiLaC stand for?

FiLaC stands for fistula laser closure. It is a minimally invasive technique that uses a radial laser fibre inserted into the fistula tract to destroy the lining of the tract from the inside, encouraging it to close and heal.

Is FiLaC available on the NHS?

Availability varies. FiLaC is more commonly offered privately in the UK, though some NHS centres with specialist colorectal units may offer it. Ask your surgeon or colorectal department about availability in your area.

How does FiLaC compare to a fistulotomy?

Fistulotomy has a higher success rate overall but involves cutting through tissue, which may affect the sphincter depending on the fistula's path. FiLaC is sphincter-sparing and has a lower risk of incontinence, but the recurrence rate tends to be higher. The right choice depends on the type and complexity of the fistula.

What is the success rate of FiLaC?

Published studies report success rates ranging from roughly 50 to 70 per cent, though results vary depending on fistula complexity, surgeon experience, and how success is defined. Your surgeon can discuss what the evidence suggests for your specific situation.

How long is recovery after FiLaC?

Recovery is generally shorter than after open fistula surgery. Many people describe returning to normal activities within one to two weeks. Pain levels are typically lower than with fistulotomy, though some discomfort and drainage in the early days is normal.

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:

  • Increasing pain, swelling, or redness near the anus
  • Fever or chills
  • Pus or foul-smelling discharge
  • New or worsening symptoms after surgery

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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