A seton is a thin, soft surgical thread or rubber loop that a surgeon places through an anal fistula tract. It keeps the tract draining so infection does not build up again, and it protects the anal sphincter muscles while the area calms down. Most setons stay in for weeks to months, and some patients keep one longer to control symptoms.

If you have just been told you need a seton, or you woke up from surgery with one, it is normal to have questions. This guide explains what a seton does, how long it usually stays, and what daily life looks like while it is in place.

What is an anal fistula, and why would I need a seton?

An anal fistula is a small tunnel between the inside of the anal canal and the skin near the anus. It often forms after an anal abscess (a pocket of infection) drains or is drained.

Many simple fistulas can be treated with a single procedure called a fistulotomy, which opens the tunnel so it heals from the inside out. But some fistulas pass through a large part of the sphincter muscles that control bowel movements. Cutting through too much of that muscle could affect bowel control. In those cases, a seton is often the safest first step.

A seton may be recommended when:

• There is still active infection or an abscess that needs to keep draining
• The fistula crosses a large amount of sphincter muscle (a "complex" fistula)
• The fistula has come back after earlier treatment
• The fistula is related to Crohn's disease

Dr. Belizaire places draining setons as part of her anal fistula care in Houston, often as the first stage of a planned treatment for the appropriate patient. You can read more about her overall approach on the anal fistula surgery page.

What does a seton actually do?

A seton keeps the fistula tract open so pus and fluid can drain out instead of collecting under the skin. This lowers the chance of another painful abscess.

There are two main types:

• Loose (draining) seton: Tied loosely so it sits comfortably in the tract. Its job is drainage and calming the infection. This is the most common type.
• Cutting seton: Tightened over time so it slowly works through the muscle. National colorectal surgery guidelines say it may be used only in selected cases, because it can affect bowel control.

Dr. Belizaire always uses a loose draining seton. There is rarely an indication for a cutting seton and they are quite painful.

How long does a seton stay in?

Most setons stay in for several weeks to a few months. The exact time depends on how quickly the infection settles and what the next step in treatment will be.

For many patients, the seton stays in for at least 6 to 8 weeks before the next procedure is planned.

A seton is often a "bridge" to definitive repair. Once the tract has matured and the inflammation is gone, the surgeon can choose a final repair. Options may include:

• Fistulotomy, if enough muscle can be safely spared
• The L.I.F.T. procedure, which closes the tract between the sphincter muscles without cutting them. Learn more on the LIFT procedure page.
• A rectal mucosal advancement flap, which covers the inner opening with healthy tissue.

Some people choose to keep a seton long term. This can make sense when a fistula is very complex such as in patients with Crohn's disease, when other repairs have not worked, or when someone prefers to avoid more surgery. A long-term seton controls drainage and infection, even if it does not cure the fistula.

Is a seton used differently for Crohn's disease?

Yes. For fistulas caused by Crohn's disease, setons are a key part of treatment and are often used alongside medicine.

Current guidelines recommend combining surgery and medical therapy for Crohn's-related fistulas. The seton controls infection while medicines from your gastroenterologist calm the inflammation. Some people with Crohn's keep a seton for a long time to keep symptoms under control. If you have Crohn's, the Crohn's disease surgery page explains how surgery fits into your overall care.

What is daily life like with a seton?

Most people go back to their normal routines with a seton in place. You may notice some drainage and mild irritation, but a loose seton should not cause severe pain.

Helpful tips:

• Keep the area clean. Rinse with warm water in the shower or a sitz bath, especially after bowel movements. Pat dry gently.
• Use a pad or gauze. Some drainage is expected. A thin pad in your underwear can protect clothing.
• Do not pull on the seton. It is tied in place. You can wash around it normally.
• Keep stools soft. Fiber, plenty of water, and a stool softener if advised can make bowel movements more comfortable.
• Stay active. Walking, desk work, and most daily activities are usually fine. Ask your surgeon about heavy exercise.

Studies show that people living with a long-term seton may have concerns about body image and intimacy. These concerns are common and worth discussing openly with your care team.

When should I call my surgeon?

Call if you have signs that infection is building again or if the seton falls out.

• Fever or chills
• Pain or swelling that keeps getting worse
• Drainage that stops suddenly along with new swelling
• Heavy bleeding
• The seton comes loose or falls out

How is a seton removed?

Generally, the seton is removed as part of the second-stage surgery. On a rare occasion, setons can be removed in the office if there is no plan for a second operation. After removal, the small opening usually closes over a few weeks.

Frequently Asked Questions

Does a seton hurt?

A loose seton usually causes mild discomfort and drainage, not severe pain. Worsening pain can mean infection and should be checked.

Can I shower or bathe with a seton?

Yes. Warm water rinses and sitz baths help keep the area clean and comfortable.

Will a seton cure my fistula?

A loose seton controls infection but usually does not cure the fistula by itself. It prepares the area for a final repair, or it can be kept long term for symptom control.

Can I work with a seton?

Most people return to desk work within days. Jobs that involve heavy lifting or long periods of sitting may need adjustments.

Can a fistula come back after a seton?

Yes, fistulas can return, especially complex ones. Your surgeon will discuss which final repair gives the best balance of healing and bowel control for you.

Do I need an MRI before a seton?

Not always. Imaging such as MRI may be recommended for complex, recurring, or Crohn's-related fistulas to map the tract.

Next steps

A seton is a common, well-tested step on the way to healing a fistula while protecting bowel control. If you live in the Houston area and have questions about an anal fistula or a seton, you can request a consultation with Dr. Belizaire at houstoncommunitysurgical.com.

Sources

• Gaertner WB, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2022. PubMed
• Long-term outcome of loose seton for complex anal fistula: a two-centre study of patients with and without Crohn's disease. PubMed
• The role of loose seton in the management of anal fistula: a multicenter study of 200 patients. PubMed
• Beyond incontinence: a systematic review and meta-analysis of sexual dysfunction after anal fistula surgery. PubMed
• NIDDK (NIH). Colonic and Anorectal Fistulas. NIDDK