What is a seton?
A seton is a thin surgical thread placed through an anal fistula to help drain infection and keep the fistula open. This allows pus and fluids to drain out, helping to prevent abscesses and reduce inflammation before further treatment.
Seton drainage is often used when a fistula passes through the anal sphincter muscles. It allows the area to heal while protecting the muscles, reducing the risk of incontinence.
Why might you need seton drainage?
Your doctor may recommend a seton if you have an anal fistula, which is an abnormal connection between the anal canal and the skin around the anus. Fistulas are often caused by:
- An abscess that has burst
- Crohn’s disease or other inflammatory bowel conditions
- Previous surgery or trauma
- Infections in the anal glands
A seton helps keep the fistula open, allowing continuous drainage of fluids and preventing the build-up of infection.
Types of setons
There are different types of setons depending on your condition and treatment plan:
- Loose seton – A soft thread that keeps the fistula open to allow drainage without cutting the muscle
- Tight seton – A firmer thread that is gradually tightened to encourage the fistula to close while minimising muscle damage
- Cutting seton – Used in some cases to slowly divide the fistula tract, helping it heal over time
Your consultant will discuss which type of seton is best for you.
How is seton drainage performed?
Seton placement is a minor surgical procedure usually done under local or general anaesthetic
- The surgeon will examine the fistula and may use a proctoscope to check the anal canal
- A thin surgical thread is placed through the fistula tract, forming a loop that exits through the skin
- The seton is tied securely to allow continuous drainage
- The procedure usually takes 30 to 60 minutes and is often done as a day case, meaning you can go home the same day
What happens after the procedure?
- You may have some mild discomfort and swelling around the area
- You may notice some leakage of pus or fluid, which is normal as the seton allows drainage
- You can eat and drink as normal after the procedure
- Pain relief and stool softeners may be recommended to help with bowel movements
- You should avoid straining, heavy lifting, and strenuous activity for a few weeks
Most people return to normal activities within a few days but may need time to adjust to the seton.
How do you care for your seton?
- Keep the area clean and dry to prevent infection
- Wash gently with warm water after bowel movements
- Avoid using scented soaps or wipes that may irritate the skin
- Wear a pad or soft tissue to absorb any drainage
- Take stool softeners if needed to reduce discomfort
If you have increased pain, swelling, or signs of infection, contact your doctor.
How long will the seton stay in place?
The length of time a seton remains in place depends on the type of fistula and treatment plan
- A loose seton may be left in place for several months to allow drainage
- A tight or cutting seton may be adjusted over time to slowly close the fistula
- In some cases, once infection and inflammation have settled, further surgical repair may be needed to fully close the fistula
Your consultant will monitor your progress and discuss the next steps for your treatment.
Are there any risks?
Seton drainage is a safe and effective procedure, but like any treatment, there are some potential risks
- Mild discomfort or leakage around the seton site
- Infection or irritation, which is rare if proper hygiene is maintained
- Fistula may not fully heal, requiring further surgery
- Minor bleeding after bowel movements
If you experience severe pain, fever, or excessive bleeding, seek medical advice.
Why choose the Midlands Bowel Clinic?
- Expert colorectal surgeons experienced in treating complex anal fistulas
- Advanced diagnostic tools, including MRI and endoanal ultrasound for precise assessment
- Personalised treatment plans tailored to your needs
- Comprehensive aftercare and follow-up support to ensure the best outcome
Contact us
If you have an anal fistula and need advice on seton drainage, please contact the Midlands Bowel Clinic. We are here to help.
