Understanding fistula treatment
An anal fistula is a small tunnel that runs from inside the anal canal to an opening in the skin near the anus. It nearly always begins as an abscess: one of the tiny glands that line the anal canal becomes blocked and infected, pus collects, and the collection eventually finds its way out through the skin. Once the abscess drains, the track it made behind it often stays open — and that track is the fistula.
The pattern that brings people in is a cycle. There is a period of swelling and pain, then a discharge of pus or blood that brings relief, then a few weeks of relative calm, and then it starts again. Many patients have been through this several times, sometimes over years, and have often had one or more previous procedures elsewhere.
A fistula does not close on its own, and no amount of antibiotics will cure it — antibiotics settle the flare but leave the track intact. Surgery is the only definitive treatment.
The central challenge in fistula surgery is that the track frequently passes through the anal sphincter — the muscle responsible for bowel control. Simply laying the track open (fistulotomy) cures the fistula reliably, but if too much sphincter is divided, continence is at risk. The whole art of modern fistula surgery lies in curing the fistula without damaging that muscle.
Dr. Ankur Patel uses sphincter-saving techniques — laser closure (FiLaC), video-assisted anal fistula treatment (VAAFT), and the LIFT procedure — choosing the approach based on where the track runs, which is mapped on MRI before surgery in complex cases. Simple, low fistulas are still best treated by fistulotomy, which has the highest cure rate of all.
Types & classification
The commonest and simplest type. The track runs between the internal and external sphincters and can usually be treated with a very high cure rate.
The track crosses both sphincter muscles. Sphincter-saving techniques matter most here, since fistulotomy would divide significant muscle.
Complex, high tracks that loop above the sphincter mechanism. These need careful MRI mapping and often a staged approach with a seton.
A track that curves around the anal canal on both sides, with multiple external openings. Requires thorough drainage of every branch.
A fistula that has returned after previous surgery, usually because a branch or the internal opening was missed. Re-imaging is essential.
Fistulas arising from inflammatory bowel disease. These need combined medical and surgical management, not surgery alone.
Symptoms & causes
Symptoms to look for
- Recurrent discharge of pus, blood or fluid near the anus, often staining underwear
- A small opening or pimple-like lump in the skin around the anus
- Swelling and throbbing pain that builds up, then eases when it discharges
- Repeated abscesses in the same area
- Itching, irritation and persistent moistness
- Pain on sitting or during bowel movements
- Fever during a flare-up
- Passing gas or stool through the external opening in rare, severe cases
Common causes & risk factors
- A previous perianal abscess — the cause in the overwhelming majority of cases
- Blockage and infection of an anal gland
- Crohn’s disease and ulcerative colitis
- Tuberculosis, in a small proportion of Indian patients
- Trauma or previous anorectal surgery
- Obstetric injury after difficult childbirth
- Diabetes and impaired immunity, which raise abscess risk
- Radiation to the pelvis
- Chronic diarrhoea and poor local hygiene
When to see a surgeon
- Recurrent discharge or a persistent opening near the anus
- Repeated abscesses in the same place
- Swelling with pain and fever — an active abscess needs drainage promptly
- A fistula that has recurred after previous surgery
- Multiple openings, or fistula with diarrhoea and weight loss, which needs investigation for inflammatory bowel disease
How it is diagnosed
The external opening is usually visible, and the track can often be felt as a cord running toward the anal canal.
To locate the internal opening — identifying it accurately is the single biggest factor in preventing recurrence.
The gold standard for complex, recurrent or high fistulas. It maps the track, side branches and relationship to the sphincter before any incision is made.
An alternative or complement to MRI, giving detailed images of the sphincter and track.
Often the most informative assessment of all, done at the start of the operation with the muscles relaxed.
Where Crohn’s disease or tuberculosis is suspected, particularly with multiple or atypical fistulas.
Treatment options
The appropriate option depends on your diagnosis, examination and general health. Your clinician will explain the benefits and risks of the available approaches.
If there is an active abscess, it is drained first. The fistula itself is then addressed once the acute infection has settled.
Laying the track open so it heals from the base up. The highest cure rate of any technique — above ninety-five percent — and the right choice for low, simple fistulas where little or no sphincter is involved.
A radial laser fibre is passed along the track and withdrawn slowly, sealing it from within. No sphincter is divided, the wound is minimal, and recovery is fast. Well suited to transsphincteric tracks.
Video-assisted anal fistula treatment: a fine endoscope is passed into the track so the surgeon can see it directly, find every branch and the internal opening, cauterise the lining and close the opening. Particularly valuable in complex and recurrent fistulas.
The track is tied off and divided in the plane between the two sphincters, curing the fistula without dividing any muscle. A good option for transsphincteric fistulas.
A soft thread left through the track to drain it safely. Used as a first stage in complex or high fistulas, and where infection must settle before definitive surgery.
A flap of healthy rectal tissue is mobilised to cover and close the internal opening. Used for high or recurrent fistulas where sphincter preservation is critical.
Preparing for treatment
- MRI fistulogram arranged in advance for complex, high or recurrent fistulas
- Blood sugar control optimised — diabetes markedly affects healing
- Routine blood tests, ECG and anaesthetic review
- An enema on the morning of surgery
- Six hours fasting before anaesthesia
- Bring all previous operation notes and imaging; knowing what was done before genuinely changes the plan
The procedure, step by step
- Examination under anaesthesiaThe first and most important step. The external opening, the full course of the track and — critically — the internal opening are identified with the sphincter relaxed.
- Probing and mappingA fine probe or dye is used to define the track and find every side branch. Missing a branch is the commonest cause of recurrence.
- Clearing the trackGranulation tissue and debris are curetted out, or in VAAFT the track lining is visualised and cauterised under direct vision.
- Closing the internal openingThe opening into the anal canal is closed with sutures, a stapler or a flap, depending on the technique chosen.
- Sealing the trackWith FiLaC, the laser fibre is withdrawn slowly along the track, shrinking and sealing it circumferentially without dividing muscle.
- DrainageA seton may be left if there is residual infection, or a small drain placed to prevent a collection re-forming.
- DressingA light dressing. Detailed instructions on sitz baths and wound care are given before you leave.
Recovery timeline
- Day 0 – 1Home the same day or the next morning. Moderate soreness controlled with painkillers. Sitz baths started.
- Days 2 – 7Sitz baths two to three times daily and after each bowel movement. Some serous discharge is expected and normal. Desk work usually resumes within this week.
- Weeks 2 – 4Discharge reduces steadily. Regular follow-up to confirm the wound is healing from the base upward and not closing over prematurely.
- Weeks 4 – 8Complete healing in most cases. Fistulotomy wounds take longer to heal but heal very reliably.
- Follow-upReview at three and six months is important, because a fistula that is going to recur usually does so within the first six months.
Benefits of this approach
- Sphincter-saving techniques protect bowel control
- Laser and VAAFT leave minimal wounds and need no packing
- Day-care or single-night stay for most patients
- Return to desk work within a few days
- Direct visualisation with VAAFT finds hidden branches that cause recurrence
- Repeatable — if a laser closure does not take, other options remain open
- Far less post-operative pain than traditional wide fistulotomy
Risks & possible complications
Every operation carries risk, and you should hear about it before you consent rather than afterwards. These are discussed individually at consultation in the context of your own health.
- Recurrence — higher with sphincter-saving techniques than with fistulotomy, which is the trade-off for protecting continence
- A new abscess if the track becomes blocked before healing completes
- Impaired flatus control if sphincter division is required
- Delayed healing, especially in diabetics and smokers
- Bleeding or local infection
- Complex fistulas may need more than one procedure — this is planned and explained upfront, not a failure
What affects the cost
- Whether the fistula is simple or complex, single or multi-branched
- The technique used — fistulotomy, LIFT, FiLaC laser or VAAFT
- Whether MRI fistulogram is required beforehand
- Whether staged surgery with a seton is planned
- Anaesthesia, length of stay and follow-up dressings
- Covered by most health insurance policies; the team assists with pre-authorisation