Advancement Flap (Fistula or Fisture Repair)

An operation that borrows a flap of your own healthy nearby tissue to seal the internal opening of a complex fistula — or to rebuild the anal canal after a stubborn fissure — without dividing sphincter muscle.

Request a consultationSurgery is arranged with a coordinator by phone.

Setting: Operative
Anesthesia: General or spinal anesthesia in the operating room, typically as a same-day (outpatient) procedure
Back to work: Most patients are back to light activity and desk work within two to four weeks; strenuous activity waits several weeks to protect the repair
Pain relief: Oral pain medicine and warm sitz baths; the repair area is sore for the first week or two
Success rate: 60-80%
Recurrence: 10-30%

What it is

What is an Advancement Flap?

An advancement flap is a versatile surgical technique used to repair complex anorectal conditions by mobilizing a piece of healthy, well-vascularized tissue to cover a defect. This procedure is primarily used for two distinct conditions: complex anal fistulas and chronic anal fissures, particularly those associated with anal stenosis.

For Fistula Repair

For a complex anal fistula, an endorectal (or anorectal) advancement flap is a sphincter-preserving operation designed to close the internal fistula opening. The procedure involves creating a flap of mucosa, submucosa, and sometimes a portion of the internal sphincter muscle from the rectum just above the fistula opening. This flap is then 'advanced' down to cover the debrided and closed internal opening, effectively sealing the source of the fistula from inside the rectum. The external portion of the tract is curetted and left open to drain and heal by secondary intention.

For Fissure/Stenosis Repair (Anoplasty)

For a chronic anal fissure that has failed other treatments, or for anal stenosis (a fibrous narrowing of the anal canal), an anoplasty using a cutaneous advancement flap is performed. This involves excising the fissure and associated scar tissue. A flap of healthy, pliable perianal skin is then created and 'advanced' into the anal canal to cover the defect. This procedure, known as an anoplasty, widens the anal canal and brings a robust blood supply to the area to promote healing.

Am I a candidate?

Who is a Good Candidate for an Advancement Flap?

For Fistula Repair: This procedure is ideal for patients with complex, high transsphincteric fistulas where a fistulotomy would carry an unacceptable risk of incontinence. It is a good option for fistulas with a well-defined tract, often after a draining seton has been in place. It is particularly useful for anterior fistulas in women.
For Fissure/Stenosis Repair: An anoplasty is considered for patients with chronic anal fissures that have failed medical and surgical therapies (like sphincterotomy) or for fissures associated with low sphincter pressures where a sphincterotomy is contraindicated. It is also a primary treatment for symptomatic anal stenosis that has not responded to conservative measures like dilation.

How it's done

1Under anesthesia, the internal opening of the fistula — the source — is cleaned out and closed.
2A flap of healthy rectal lining just above it is freed up and slid down over the closed opening, patching it from the inside.
3The flap is stitched in place. No sphincter muscle is divided.
4The outer part of the tract is cleaned and left open to drain while everything heals.
5The same idea — moving healthy tissue in — is used as an anoplasty to repair a chronic fissure or a narrowed anal canal, using a small flap of nearby skin instead.

What to expect

Same day
Most patients go home the same day.
First 1–2 weeks
Soreness and a little drainage. Keep stools soft with fiber and fluids — straining is the flap's enemy.
2–4 weeks
Light activity and desk work for most patients; no heavy lifting or strenuous exercise while the flap takes.
About 6–8 weeks
Complete healing for most repairs.
Follow-up
Visits to confirm the flap has taken and the openings have closed.

Risks & considerations

What are the Risks?

While an advancement flap is a safe and effective procedure in the right hands, it has potential risks, including:

Flap Dehiscence or Necrosis: The most common complication is partial or complete breakdown of the flap, which can lead to failure of the repair and fistula or fissure recurrence. This can be caused by tension on the suture line, infection, or poor blood supply.
Infection or Abscess: A wound infection or abscess can develop at the repair site.
Bleeding: Postoperative bleeding can occur, though it is usually minor.
Fecal Incontinence: There is a small risk of new or worsened incontinence to flatus or stool. This can be due to the dissection itself or subtle injury to the sphincter muscles. For fistula repairs, the risk is generally lower than with sphincter-cutting procedures.
Recurrence: The original fistula or fissure may recur, or stenosis may redevelop over time.

Sources