Will I need a seton before laser fistula treatment?

Sometimes. If the tract is actively infected, branched or has never been drained, a soft draining seton is placed for six to twelve weeks so the inflammation resolves and the tunnel matures into a clean single channel. Laser ablation of a mature tract works considerably better than ablation of an inflamed one.

Will FiLaC affect my control of gas or stool?

FiLaC is designed to avoid this. The laser fibre travels inside the tract, so the sphincter muscle the tract passes through is never divided. This is why the technique is preferred for high trans-sphincteric tracts, anterior fistulas in women, and patients who have already had fistula surgery.

Do I need an MRI before fistula surgery?

For a simple, low, first-time fistula, examination under anaesthesia may suffice. For recurrent, high, multi-branched or Crohn's-related disease an MRI fistulogram is strongly advised, because undetected secondary branches are the commonest reason a fistula appears to recur.

Home/Conditions/Anal Fistula

Anal fistula · Fistula-in-ano · ناسور شرجي

FiLaC in Dubai — the fistula is sealed from the inside, the muscle is never cut.

A fistula is a tunnel. Traditional surgery lays it open, which means dividing whatever muscle lies across it — and that is where continence is lost. Fistula-tract Laser Closure works from within the tunnel itself, destroying its lining and collapsing it shut, with the sphincter left intact.

Sphincter-preserving by design 20–30 minute procedure Day case Repeatable if needed

Book a fistula assessment Ask about fistula

What a fistula is, and why FiLaC spares the muscle

A fistula is a small tunnel between the bowel lining and the skin near the anus
Traditional "lay-open" surgery cuts along the tunnel — dividing any muscle in its path
FiLaC destroys the tunnel's inner lining from within with a radial fibre, then it collapses shut
Because nothing is cut, the sphincter muscle is never at risk

The full anatomy and technique diagrams are further down this page.

At a glance

Procedure: FiLaC — Fistula-tract Laser Closure, 1470 nm radial fibre
Imaging first: MRI fistulogram or endoanal ultrasound in complex cases
Theatre time: 20–30 minutes
Sphincter: not divided at any point
Work: desk work in 2–3 days
Best for: trans-sphincteric, high, recurrent and multi-tract disease

Medically reviewed by Dr Kerim Erdem Ulucay, Specialist General & Laparoscopic Surgeon (DHA-licensed) Last reviewed: 25 August 2026 Next review due: August 2027 Reading time: 10 minutes

Understand it, then decide

The condition and the cure, kept separate

Fistula is the condition where understanding the anatomy genuinely changes the decision you make. Start here.

Component A · The Disease

What an anal fistula is — and where it came from

An anal fistula is an abnormal tunnel connecting the inside of the anal canal to the skin around the anus. It has an internal opening where it started, a tract that runs through or around the sphincter muscles, and one or more external openings on the skin that discharge pus, blood or faecal fluid.

Around nine in ten fistulas begin the same way. Small glands sit between the two sphincter muscles and drain into the anal canal at the dentate line. If one becomes blocked and infected, an abscess forms and takes the path of least resistance outward through the tissues until it discharges through the skin. That drainage path — the cryptoglandular theory — is your fistula. This is why so many patients say the same sentence: "It started as a boil that burst, and it has never properly healed since."

A fistula does not heal on its own. The tract becomes lined with epithelium and granulation tissue that keeps it open indefinitely. Antibiotics settle a flare, but they cannot close a tunnel. Only a procedure will do that.

A minority of fistulas arise from Crohn's disease, tuberculosis, previous radiotherapy, obstetric injury or malignancy. Identifying these matters enormously, because treating a Crohn's fistula as if it were cryptoglandular is a route to repeated failure. That is part of what your assessment is for.

Anatomy & causes, Parks classification, symptoms, and management options at a glance

Symptoms

The everyday picture

Persistent discharge. Pus, blood or a yellow-brown fluid staining underwear. The single most reliable sign, and the one that makes patients wear a pad in silence for years.
A small opening near the anus that may look like a spot or a dimple, sometimes with a visible bead of granulation tissue.
Cyclical swelling and relief. The opening seals, pressure builds, pain increases over days, then it discharges and the pain vanishes — and the cycle restarts.
Skin irritation and odour around the anus from constant moisture.
Discomfort on sitting — long meetings and long drives become the worst part of the day.

When it is an abscess, not just a fistula

Rapidly increasing severe pain over 24–72 hours, throbbing, worse on sitting.
A hot, hard, tender swelling beside the anus.
Fever, rigors or feeling systemically unwell.
Difficulty passing urine or spreading redness across the buttock.

An anal abscess is a surgical emergency, not a laser case. It needs drainage the same day. Antibiotics alone will not clear pus under pressure, and delay in a diabetic or immunosuppressed patient risks a rapidly spreading perineal infection. Attend an emergency department or contact the clinic immediately — the laser conversation happens weeks later, once the infection is controlled.

Classification — Parks types, and why it decides everything

The Parks classification describes how the tract relates to the two sphincter muscles. It is not academic: it is the difference between a fistula that can be laid open safely and one where laying it open would leave you incontinent.

Intersphincteric

Runs between the internal and external sphincter. The most common and the simplest. ~45%.

Low risk · FiLaC or fistulotomy both viable

Trans-sphincteric

Crosses the external sphincter to reach the skin. ~30%. Height of the crossing is critical.

Core FiLaC indication

Suprasphincteric

Loops up over the whole sphincter complex before descending. ~20%.

Sphincter-preserving technique essential

Extrasphincteric

Bypasses the sphincter entirely, entering above it. ~5%. Often secondary to another disease.

Complex · treat the underlying cause first

Why imaging is not optional in complex disease. An MRI fistulogram or endoanal ultrasound maps the tract, finds secondary branches and horseshoe extensions, and identifies the internal opening. Missing a side branch is the commonest cause of a fistula that "recurs" — in reality it never fully closed. Fifteen minutes in a scanner is worth more than any surgeon's guess.

Understanding your fistula

Reading your MRI: what we look for

The primary tract — its full course between the internal and external opening
Any secondary tracts or branches, including horseshoe extensions
The internal opening, and its position relative to the sphincter muscles
Signs of an undrained collection that needs treating first

This is explained on the imaging itself, with you, at your consultation.

"Why has my fistula come back?"

A missed secondary tract or branch that was never treated
An abscess that was drained but the underlying tract left untouched
The internal opening not fully closed at the first attempt
A new, unrelated tract forming separately from the original one

Most recurrence has a specific, identifiable cause — not "bad luck."

Now show me the treatment

Component B · The Laser Treatment

FiLaC — Fistula-tract Laser Closure, step by step

FiLaC treats the tract as a cylinder to be destroyed from within. A thin radial laser fibre is passed along the whole length of the tunnel from the external opening to the internal opening. As it is withdrawn at a controlled, steady rate, it emits 1470 nm energy in a 360° ring.

That energy does three things at once. It ablates the epithelial lining that keeps the tract patent. It shrinks the surrounding collagen so the tunnel contracts inward on itself. And it seals the small vessels feeding the chronic inflammation. What was a cylinder becomes a cord of scar tissue.

The internal opening is then closed — usually with a small absorbable suture, sometimes with an advancement flap in more complex disease. Closing the source is essential: if faecal content can still enter the tract from the anal canal, no ablation will hold.

At no point is any sphincter muscle divided. The fibre passes through the tract, which already runs through the muscle. That single fact is why FiLaC exists and why it is the technique of choice for high trans-sphincteric fistulas, for patients who have already had sphincter surgery, and for women with obstetric injury who cannot afford to lose any further continence reserve.

FiLaC technique — radial laser fibre ablating an anal fistula tract from within

Inside the theatre — the six stages

1Before the day
Mapping
MRI fistulogram or endoanal ultrasound reviewed and the tract drawn out with you, so you know the plan before you are asleep. In heavily infected or multi-branched disease a draining seton is placed first and FiLaC follows 6–12 weeks later, once the tract is clean and mature.
20–8 minutes
Examination under anaesthesia
Under spinal or short general anaesthesia the tract is probed gently, hydrogen peroxide or dye confirms the internal opening, and any secondary branches are identified and curetted.
38–14 minutes
Tract preparation
The tunnel is cleaned of granulation tissue and debris with a fine curette and irrigation. A clean tract ablates evenly; a dirty one does not. This step is unglamorous and it decides the outcome.
414–22 minutes
Laser ablation
The radial fibre is advanced to the internal opening and withdrawn at roughly 1 mm per second while emitting approximately 10–13 W. Energy density is kept constant along the full length so no segment is under-treated.
522–28 minutes
Closure of the internal opening
An absorbable suture closes the source. Where the opening is large or the tissue is scarred from previous surgery, a mucosal advancement flap is used instead.
628–30 minutes
Drainage and finish
The external opening is left open to drain — deliberately. A sealed skin opening traps fluid and causes the recurrences people blame on the laser. No packing, no drain.

Watch it in motion

Animated illustration — no real patients or staff

FiLaC — animated walkthroughFibre threaded tract-to-tract, sealing as it withdraws · silent · 12s loop

Benefits over conventional fistula surgery

Continence protected

Fistulotomy — laying the tract open — carries a real risk of impaired control when significant muscle must be divided. FiLaC divides none. For high tracts this is not a preference, it is the whole argument.

No large open wound

Conventional surgery can leave a wound needing packing for weeks or months. FiLaC leaves the small external opening and a tract that closes from within.

Repeatable without penalty

If a tract does not fully close, FiLaC can be repeated — because nothing was removed and no muscle was sacrificed the first time. Contrast that with a failed fistulotomy, where the tissue is simply gone.

Suits complex & recurrent disease

High trans-sphincteric, suprasphincteric, multi-tract, previously operated and anterior fistulas in women are exactly the cases where sphincter-sparing technique earns its place.

Day case, fast return

Home the same day. Desk work in two to three days rather than the weeks of dressing changes that follow a laid-open tract.

Minimal bleeding

The wavelength coagulates as it ablates, so the field stays dry and post-operative bleeding is uncommon.

An honest word on success rates. Published primary healing rates for FiLaC in complex fistula generally sit in the region of 65–80%, rising with a second session and with meticulous closure of the internal opening. That is lower than fistulotomy's healing rate — and it is the right trade, because fistulotomy achieves its number by cutting muscle you cannot grow back. Anyone quoting you a near-certain cure for a complex fistula, by any technique, is not being straight with you.

Pain: an honest comparison

FiLaC laser tract closure

LIFT procedure intersphincteric ligation

Fistulotomy laying open + packing

6–7

0–10 visual analogue scale at 24–72 hours. Fistulotomy's score reflects the ongoing dressing changes as much as the operation itself.

Recovery timeline

Day 0Home the same afternoon. Mild soreness. Normal diet, oral analgesia, a short antibiotic course where indicated.

Days 1–3Some serous discharge from the external opening — expected, and a good sign. Sitz baths twice daily. Desk work resumes.

Weeks 1–3Discharge steadily reduces as the tract fibroses. Keep the skin dry. Avoid gym, cycling and swimming pools.

Weeks 4–8External opening closes in most patients. Clinic review. Full activity resumed.

Months 3–6Healing confirmed clinically, with repeat MRI in complex cases. A second FiLaC session is offered if a tract persists.

Contact the clinic if: discharge becomes thick, foul-smelling or increases after week two; a painful swelling reappears; you develop a fever; or you notice any change in your control of gas or stool. Early review resolves nearly all of these.

The procedure, step by step

FiLaC, in four steps

The tract is probed and its full length confirmed under direct vision
A radial fibre passes along the entire tunnel from the external to the internal opening
360° laser energy ablates the tract lining as the fibre is slowly withdrawn
The internal opening is closed; the tract is left to collapse and fibrose shut

The full illustrated technique diagram is above, in the treatment section.

Patient stories — by consent only

We do not publish stock or invented testimonials on this site
Patients who choose to share their experience — including complex, previously-operated fistulas — do so in writing, with explicit consent
Ask us directly and we can put you in touch, where a patient has agreed to be contacted

Ask about patient experiences

Individual results and recurrence risk vary with fistula complexity.

Bring your MRI. Bring your previous operation notes.

Fistula is the condition where a second opinion is worth most — because the classification, not the surgeon's enthusiasm, should decide the operation. Send your imaging on WhatsApp and it will be reviewed before you even come in.

Book an assessment Send my MRI report

Every option, not just ours

How FiLaC compares with the alternatives

In fistula surgery, the choice is always a negotiation between healing rate and continence. Here is that negotiation, written out.

Technique	Best suited to	Continence risk	Trade-off
Fistulotomy (laying open)	Low intersphincteric tracts only	Low if truly low; significant if the tract is high	Highest healing rate of any technique — but it buys that by dividing muscle.
Seton (draining)	Sepsis control, Crohn's, staging before definitive surgery	None	Controls the disease rather than curing it. Often the correct first step, not the last.
FiLaC (laser closure)	Trans-sphincteric, high, recurrent, multi-tract	Minimal — no muscle divided	Moderate primary healing; repeatable without further cost to the sphincter.
LIFT procedure	Trans-sphincteric with a well-defined intersphincteric portion	Low	Good results in the right anatomy; requires a discrete tract to ligate.
Advancement flap	High tracts with healthy rectal mucosa	Low to moderate	Effective but technically demanding, with a longer recovery.

Fistula questions

What patients ask before booking

Can an anal fistula heal without surgery?

Essentially no. The tract becomes lined with epithelium and granulation tissue that keeps it permanently open. Antibiotics will settle an acute flare and creams will soothe the skin, but neither closes a tunnel. Left alone, a fistula tends to branch and cause repeated abscesses — and long-standing untreated fistulas carry a small but real risk of malignant change.

What is the success rate of FiLaC?

Published primary healing rates for FiLaC in complex fistula generally fall in the region of 65–80%, improving with a second session and with meticulous closure of the internal opening. Simple tracts do better than complex ones, and Crohn's-related fistulas do less well than cryptoglandular ones. You will be given a realistic figure for your specific anatomy rather than a headline number.

Will I need a seton first?

Sometimes. If the tract is actively infected, branched, or has never been drained, a soft draining seton is placed for six to twelve weeks. It is a thin flexible loop that keeps the tract draining while the inflammation resolves and the tunnel matures into a clean, single channel. FiLaC on a mature tract works considerably better than FiLaC on an angry one. It is a delay that buys success.

Will I lose control of gas or stool?

FiLaC is specifically designed to avoid this. The laser fibre travels inside the tract, so the sphincter muscle that the tract passes through is never divided. This is the principal reason the technique was developed, and it is why it is preferred for high tracts, for anterior fistulas in women, and for anyone who has already had fistula surgery.

I have Crohn's disease. Can I have FiLaC?

Often yes, but only as part of a joint plan with your gastroenterologist and only when the bowel disease is medically controlled. Sphincter-preserving techniques are particularly valuable in Crohn's because these patients frequently face repeated procedures over a lifetime and cannot afford cumulative muscle loss. Healing rates are lower than in cryptoglandular disease, and you will be told that plainly before you decide.

How long before the discharge stops?

Discharge usually reduces markedly within two to three weeks and stops as the tract fibroses and the external opening closes, most often between weeks four and eight. Discharge that increases after week two, or becomes thick and foul-smelling, should be reviewed rather than waited out.

Can FiLaC be repeated if the fistula does not close?

Yes, and this is one of its defining advantages. Because no muscle was divided and no tissue removed, a second session is technically straightforward and carries no additional continence cost. Where a residual tract is found, a repeat ablation with reassessment of the internal opening is usually offered at around three months.

Do I need an MRI before treatment?

For a simple, low, first-time fistula, examination under anaesthesia may be sufficient. For anything recurrent, high, multi-branched, or associated with Crohn's disease, an MRI fistulogram is strongly advised. Undetected secondary branches are the single commonest reason a fistula appears to recur — planning around a scan is far more reliable than planning around a probe.