Laser anal fistula treatment (FiLaC)

Laser anal fistula treatment that seals the tunnel without cutting the muscle.

Laser closure heals less often than cutting the tunnel open, and Dr Daniel Lee will tell you that plainly, but it keeps every other option open if it doesn't work first time.

What happens, step by step
Mount Elizabeth Novena  ·  Mount Alvernia  ·  Parkway East  ·  Gleneagles  ·  Farrer Park
Dr Daniel Lee in theatre scrubs preparing for a laser anal fistula procedure
20+Years in surgery
FRCS (Edinburgh)
Fellow, Royal College of Surgeons of Edinburgh
Fellowship, Leeds
Colorectal fellowship, John Goligher Unit, St James's University Hospital
Ex-Head, KTPH
Former Head of Colorectal Surgery and Surgical Lead, Geriatric Surgery
Faculty, NUS
Adjunct Senior Clinical Lecturer, NUS and Lee Kong Chian School of Medicine
At a glance

Laser anal fistula treatment in four facts.

Muscle cut
None
The sphincter is left whole
Scan first
MRI or ultrasound
To find every branch of the tunnel
Seton first
At least 2 months
A soft thread lets the tunnel drain and settle
Heals first time
About 57%
In pooled studies; more heal with a second go

The 57% figure is from a 2025 review of 24 studies and 1,503 patients. It is an average across many surgeons and many kinds of fistula, not a prediction for yours.

How laser closure works

The tunnel is cleaned, then sealed from inside as the fibre is drawn out.

A fistula usually starts from an infected gland just inside the back passage. The infection tracks through or around the sphincter muscle and opens on the skin, so the tunnel has an inner opening and an outer one. You can read more about the condition on the anal fistula page.

In FiLaC (fistula-tract laser closure), Dr Lee cleans the tunnel, then passes a thin laser fibre in from the outside. Its tip gives off energy all the way round, and as he draws it back slowly the heat shrinks the tunnel's walls together and seals it.

He closes the inner opening with a stitch rather than cutting it out, because cutting widens the hole and the bleeding soaks up laser energy. The outer opening is cored out and widened, so anything left can drain while the tunnel heals behind it. Nothing is divided, so the risk to bowel control from the procedure itself is very low.

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  1. Inner opening, closed with a stitch, not cut out
  2. The fistula tunnel
  3. Heat at the fibre tip seals the tunnel as it's drawn back
  4. The sphincter muscle, which is not cut
  5. Outer opening, widened so it can drain
Honestly these problems are way more common than you think and we see this all the time. And the truth of the matter is that there's nothing to be embarrassed about.
Dr Daniel Lee
Is this you?

Signs of an anal fistula that laser closure may help with.

A fistula often follows an abscess near the back passage. If one of these sounds familiar, it's worth a proper look.

  • A small opening near the anus that keeps leaking pus or blood
  • Soreness or swelling that builds up, then eases when it drains
  • An abscess that was drained but keeps coming back
  • A fistula that came back after an earlier operation
When to be seen sooner

A painful, swollen, hot lump with fever needs care the same day.

That is usually an abscess, and it needs draining first. Laser closure is never done on an active infection; it comes later, once the area has settled.

Who it suits

Who laser anal fistula treatment suits, and who it doesn't.

The more muscle a fistula runs through, the more a cutting operation risks bowel control, and the more a sphincter-saving option makes sense.

Laser is a good fit for

  • Fistulas that run through a lot of sphincter muscle, where cutting it open would risk bowel control
  • Fistulas that have come back after earlier surgery
  • Women, especially with a fistula at the front, where there's less muscle to spare
  • A fistula that has been settled with a seton for at least 2 months

Another option may serve you better

  • An active abscess or infection, which is drained first
  • Active Crohn's disease, which is treated medically first
  • A fistula between the back passage and the vagina
  • A low, simple fistula through very little muscle, where laying it open heals more often
Step by step

From first scan to a healed tunnel, one step at a time.

Laser closure is a staged treatment. Here's the order it happens in.

  1. First visit

    Examination and a plan

    Dr Lee examines the area and explains what kind of fistula it's likely to be and what your options are.

  2. Before surgery

    A scan to map the tunnel

    An MRI or an ultrasound from inside the back passage shows every branch and any hidden pocket of infection. Missed side branches are one of the main reasons laser closure fails.

  3. At least 2 months

    A seton to settle the tunnel

    A soft loose thread is placed through the tunnel so it can drain and firm up. If it is still producing pus at the end of this time, the laser waits.

  4. Procedure day

    Laser closure as a day procedure

    Under anaesthetic, the seton comes out, the tunnel is cleaned and sealed with the laser, the inner opening is stitched shut and the outer one is widened. Dr Lee may use a small camera (VAAFT) to check the tunnel first.

  5. Weeks after

    Daily flushing and reviews

    You rinse the outer opening each day while it heals, and come back for reviews until the tunnel has closed.

Illustration of an operating theatre with lights, an operating table and a monitor, where laser anal fistula treatment is done
Laser vs other options

How laser compares with the other anal fistula operations.

Every fistula operation trades healing against bowel control. Operations that cut more muscle tend to heal more often, but put bowel control at more risk.

Healing and bowel-control figures from published studies for fistulotomy, LIFT, advancement flap and FiLaC
OperationWhat it doesHealed in studiesChange in bowel control in studies
FistulotomyLays the tunnel open, cutting the muscle it runs through84% and 87% in two large studiesAbout 13% in one review; higher in others
LIFTTies and divides the tunnel between the two sphincter musclesAbout 69% to 79%About 1.4% to 1.6%
Advancement flapCovers the inner opening with a flap of lining66% to 87%About 13% on average, higher with thicker flaps
Laser closure (FiLaC)Seals the tunnel from inside, no muscle cutAbout 57% first timeUnder 1% new change

These figures come from different studies of different patients, so they can't be compared head to head, and studies define a change in bowel control differently; fistulotomy is mostly used for low, simple fistulas. The laser figures come from a 2025 review of 24 studies; the others come from published studies of each operation, including the American colorectal surgeons' 2022 guideline.

What the studies show

What published research says about laser anal fistula treatment.

These are results from other surgeons' published studies, not a promise of your result. Each one links to the paper.

About 57% heal first time

In a 2025 review of 24 studies and 1,503 patients, about 57% of fistulas healed after one laser closure. Of those that healed, about 1 in 5 came back later.

Bowel control problems were rare

New problems with bowel control were rare, about 0.57% in the pooled studies. In a 117-patient series, nobody lost control of solid or liquid stool; 1.7% noticed minor wind or mucus leakage.

If it doesn't heal, options stay open

In that same series, 64% healed first time, and 88% had healed by the end of the study, most of them after a different, conventional operation. About half the fistulas that did not heal became lower, simpler ones that were easier to treat. A repeat laser closure healed about 49% in pooled studies.

Why Dr Lee prepares the way he does

Laser closure tends to fail when a side branch is missed, the tunnel is uneven, or its lining isn't fully cleared. That's why he scans first, settles the tunnel with a seton, stitches the inner opening, and sometimes uses a camera to see inside before sealing it.

Recovery

Recovery after laser anal fistula treatment, and what is normal.

Some drainage for a few weeks

The widened outer opening is meant to leak a little while the tunnel heals behind it. A pad and a daily rinse are all most people need.

Back to routine quickly

Because there's no large wound and no muscle cut, most people get back to desk work within days. Dr Lee advises on exercise at your review.

How you'll know it is healed

The drainage stops and the outer opening closes over. Dr Lee checks this at review, and sometimes asks for a repeat scan to be sure.

A quiet clinic lounge with sofas and a city view where patients wait before their review
Fees & MediSave

Fees for laser anal fistula treatment, and how MediSave and insurance apply.

Your fee is explained clearly at consultation, before anything is scheduled. Laser closure is usually a day-surgery procedure, with the seton placed at an earlier sitting.

Cost at a glance

Nearest national benchmark: conventional (open) fistula excision, TOSP SF833A

Surgeon’s fee (national benchmark, GST included)

from SGD 2,398

MOH range SGD 2,398 to 3,924is for the conventional (open) surgery, not the laser version; MOH publishes no laser-specific figure, so use it as a rough guide only. Dr Lee’s own laser fee may sit inside or outside this range and is confirmed at consultation.

Anaesthetist’s fee (national benchmark, GST included)

from SGD 763

MOH range SGD 763 to 1,090. The anaesthetist bills separately; the clinic puts the fee in your written estimate.

Hospital and day-surgery fees

quoted when you ask

Billed separately, and shown in your written estimate.

What will you pay in cash?

It depends on your insurer and plan, so the clinic works it out for you.

Leave your name and mobile, then add your insurer and plan name. No IC or policy number needed. You get the estimate in writing, before anything is booked. The estimate is information only, the decision stays yours.

You can check surgeon fees against the published MOH fee benchmark page.

Anaesthetist, imaging and hospital fees are charged separately and vary by hospital.

Paying with MediSave and insurance

MediSave

Checked for your case

Whether MediSave applies, and how much, depends on how each stage is coded under MOH's Table of Surgical Procedures and its withdrawal limits. The team checks this before you book.

Integrated Shield

Your plan, confirmed first

Many Integrated Shield Plans cover fistula surgery, but plans differ. The team helps you get pre-authorisation where your insurer asks for it.

Paperwork

We handle the forms

The team fills in the claim forms and liaises with your insurer where possible, so you can focus on getting better.

Insurance accepted

The plans we work with.

Dr Daniel Lee practises with Colorectal Clinic Associates (CCA). The clinic works with the insurers below, and the team assists with claims and eligibility checks.

Integrated Shield Plans
Corporate insurance partners
Common questions

Laser anal fistula treatment, answered plainly.

Will laser treatment affect my bowel control?
Protecting bowel control is the point of this operation. No muscle is cut, and in pooled studies new bowel-control problems were about 0.57%. Dr Lee will talk you through your own risk, which depends on the fistula.
Why do I need a seton first, and for how long?
A seton is a soft, loose thread that keeps the tunnel draining so the infection settles and the walls firm up. Dr Lee leaves it in for at least 2 months before laser. If it's still producing pus by then, he waits, because sealing an infected tunnel tends to fail.
Will the wound keep draining after laser?
For a few weeks, yes. The outer opening is widened on purpose so that anything left can drain out. You will rinse it daily and wear a pad. It should slowly dry up as the tunnel closes.
How will I know it has healed?
The drainage stops and the outer opening closes over and stays closed. Dr Lee checks this at review. If there's doubt, a repeat scan settles it.
What happens if the laser doesn't work?
Because the muscle was not touched, nothing has been lost. As Dr Lee puts it in his teaching slides, laser closure works “without burning surgical bridges”. The fistula can be treated again with laser or another operation. In one 117-patient series, about half of those that did not heal became lower and simpler to fix.
Is FiLaC the same as VAAFT?
No. VAAFT uses a small camera to see and clean the tunnel from inside; FiLaC uses laser to seal it. They are often used together. The anal fistula page covers VAAFT and the other operations.
Is laser anal fistula treatment covered by MediSave or insurance?
It may be. MediSave depends on how each stage is coded and its withdrawal limits, and Integrated Shield cover depends on your plan. The team checks both before anything is booked.
Where Dr Lee operates

Laser anal fistula treatment at five private hospitals.

Mount Elizabeth NovenaSpecialist Centre, #10-48/4938 Irrawaddy Road, Singapore 329563
Mount AlverniaMedical Centre, Block D #08-62820 Thomson Road, Singapore 574623
Parkway EastMedical Centre, #05-08319 Joo Chiat Place, Singapore 427989
GleneaglesMedical Centre, #06-166 Napier Road, Singapore 258499
Connexion, Farrer ParkFarrer Park Medical Centre, #14-121 Farrer Park Station Road, Singapore 217562
Next steps

A short message is enough to begin.

Send your name, number and what you're noticing. Dr Lee's team will reply on WhatsApp and find a time and place that suits you.