VAAFT and Laser Fistula Surgery: How Sphincter-Saving Techniques Work

For most of surgical history, treating an anal fistula meant laying the track open. It worked reliably, and where the track ran low it still does. The problem was always the fistulas that ran through significant sphincter muscle, where cure came at the cost of continence.

Two techniques in particular have changed how those fistulas are approached: VAAFT and laser closure. They work on quite different principles, and understanding them helps explain why a surgeon might recommend one over the other.

VAAFT: being able to see inside the track

The single biggest cause of fistula recurrence is a missed side branch or a missed internal opening. Traditionally, surgeons found the track by feel and by passing a probe — a technique that works well for simple fistulas and less well for complex ones.

VAAFT — video-assisted anal fistula treatment — solves this by putting a camera inside the track. A very fine endoscope, called a fistuloscope, is introduced through the external opening and advanced along the tunnel under irrigation.

For the first time the surgeon can actually see the inside of the fistula: where it runs, where it branches, and precisely where the internal opening lies. Anything hidden is found rather than guessed at.

What happens during VAAFT

• The fistuloscope is introduced through the external opening and the track is irrigated to give a clear view
• The entire tunnel and all side branches are inspected directly
• The internal opening is identified precisely and confirmed from inside the anal canal
• The lining of the track is destroyed under direct vision using a diathermy electrode
• Debris and necrotic tissue are flushed out
• The internal opening is closed with sutures or a stapler
• No sphincter muscle is divided at any stage

FiLaC: sealing the track with laser energy

Laser closure works on a different principle. A radial-emitting laser fibre — one that delivers energy in all directions rather than forward — is passed to the far end of the cleaned track.

The fibre is then withdrawn slowly and steadily. As it retracts, laser energy is delivered circumferentially into the tunnel wall. The heat destroys the lining and causes the collagen in the surrounding tissue to contract, so the tunnel shrinks and seals along its whole length.

The internal opening is closed separately, usually with a suture or a small flap. Again, no muscle is divided.

The wound is essentially two pinholes. There is nothing to pack, and no daily dressing.

Which technique for which fistula

• Low, simple intersphincteric fistula: fistulotomy remains the best option — highest cure rate, minimal risk to continence
• Transsphincteric fistula with a single straight track: FiLaC laser closure suits this well
• Complex or branching fistula: VAAFT, because direct visualisation finds branches that other techniques miss
• Recurrent fistula after failed previous surgery: VAAFT, often after MRI mapping, to identify what was missed
• High or suprasphincteric fistula: usually a staged approach — seton first to allow inflammation to settle, then a definitive procedure
• Very wide or long-standing track: sometimes VAAFT and laser are combined, using the scope to find and clear, and the laser to seal

Success rates, stated honestly

Published success rates for FiLaC and VAAFT generally fall in the range of seventy to eighty-five percent for appropriately selected fistulas. Fistulotomy exceeds ninety-five percent.

That gap is real and should be part of the conversation. It exists because these techniques deliberately avoid dividing the muscle that would guarantee the cure.

What makes the trade-off worthwhile is that failure here is recoverable. If a laser closure does not take, a second attempt, a LIFT procedure, or an advancement flap all remain available, and the sphincter is intact for all of them. A patient made incontinent by an over-enthusiastic fistulotomy has no such options.

What recovery involves

• Day care or a single overnight stay for most patients
• Moderate soreness for two to three days, controlled with oral painkillers
• Sitz baths two to three times daily and after each bowel movement
• Some serous or blood-stained discharge in the first one to two weeks — this is expected, not a sign of failure
• Return to desk work generally within three to seven days
• Complete healing over three to six weeks
• Follow-up at three and six months, because most recurrences declare themselves within the first six months

Why the MRI matters

For complex, high or recurrent fistulas, an MRI fistulogram before surgery is not an optional extra. It shows the exact course of the track, its relationship to both sphincters, any secondary branches, and any undrained collection.

Going into a complex fistula operation without that map means making anatomical decisions under time pressure, with an inflamed field, when the information could have been available beforehand.

If you have had a fistula recur after previous surgery and no MRI was done before that operation, it is worth asking whether one will be done before the next.

The role of the seton

Patients are often disappointed when a seton is placed rather than the fistula being definitively cured in one sitting. It helps to understand what it achieves.

A seton is a soft thread passed through the track and tied loosely outside. It keeps the track draining so that pus cannot accumulate and cause another abscess. It allows the surrounding inflammation to settle over weeks to months, which makes the tissue far more favourable for definitive surgery. And it lets the surgeon feel exactly how much muscle the track encircles.

In complex fistulas, a seton followed by a planned definitive procedure has better outcomes than attempting everything in one inflamed operation. Where this is likely, it should be explained before the first operation so it is expected rather than experienced as a setback.

Questions worth asking your surgeon

• What type of fistula do I have, and does the track cross the sphincter?
• Will an MRI be done before surgery, and if not, why not?
• Which technique are you planning, and what is the expected success rate for my particular fistula?
• What is the risk to my continence with that approach?
• Is this likely to need more than one procedure?
• What happens if it does not work — what are the next options?