How Long Does a Seton Stay in for an Anal Fistula?
At a Glance
A seton typically stays in an anal fistula for 4 to 12 weeks when used as a temporary bridge before definitive closure surgery. For patients with complex fistulas or Crohn's disease, a seton may be left in place for months or years to ensure continuous drainage and prevent recurrent abscesses.
In this answer
3 sections
How long a seton stays in place depends entirely on its medical purpose. A seton is a small piece of surgical thread or silicone placed through the fistula tract to keep it open and draining. If it is being used as a temporary step to prepare for a second, definitive surgery, it typically stays in place for 4 to 12 weeks (with an average around 8 weeks) [1]. However, if you have severe Crohn’s disease or a complex fistula where surgery poses a high risk to your bowel control, a loose draining seton might be left in long-term—sometimes for months or even years—to prevent painful abscesses from returning [2][3].
Draining Setons Before a Second Surgery
For many complex fistulas, surgeons use a “two-stage” approach. A loose draining seton is placed during the first surgery to allow the area to drain, which prevents new abscesses from forming [2]. As mentioned, this seton usually stays in place for a median of 8 weeks, typically ranging from 4 to 12 weeks [1].
During this time, the seton allows the acute infection to clear up and the local inflammation to subside [4]. The body forms a firm, mature track of scar tissue along the seton. This firm track makes the second surgery (such as a LIFT procedure or an advancement flap—surgeries designed to safely close the fistula tract) much safer and more likely to succeed [5].
Long-Term Setons for Crohn’s Disease
If your anal fistula is related to Crohn’s disease, the timeline can look very different. Because Crohn’s disease involves ongoing inflammation, fistulas can be much harder to heal completely, and aggressive surgery carries a higher risk of complications.
In these cases, a loose seton is often part of a long-term “multimodal” treatment plan [6][7]. It is frequently combined with biologic medications (like anti-TNF therapy) to calm down the immune system [8]. A loose seton may be left in place indefinitely to ensure the fistula keeps draining, which effectively prevents severe, recurrent abscesses [2][3].
While the idea of living with a seton indefinitely can sound overwhelming and frustrating, it is important to know that once the initial inflammation settles, the seton itself is usually well-tolerated. Most patients can have normal bowel movements and maintain daily hygiene. The goal of long-term seton placement is managing symptoms and preserving your bowel function, rather than curing the fistula outright [9][10].
While some studies show that removing the seton sooner (under 34 weeks) may be associated with higher healing rates in patients responding well to medication [11], other research suggests that waiting over a year before attempting a definitive surgery can improve outcomes [12].
Milestones: How Your Doctor Decides It’s Time
Whether you are waiting for a second surgery or waiting to see if a biologic medication is working, your surgeon will look for specific milestones during your follow-up visits before deciding to remove the seton or proceed to the next step:
- Resolution of infection: The initial abscess must be completely drained, and any active infection must be under control [4].
- Reduced inflammation: The pain, swelling, and redness around the anus should significantly improve [4].
- Decreased drainage: The amount of pus or fluid draining from the fistula should noticeably decrease, indicating that the area is calming down [13].
- Clear imaging: Surgeons often use an MRI (magnetic resonance imaging) or an endoanal ultrasound (an ultrasound probe placed inside the anus) to get a clear picture of the fistula tract under the skin [14][15]. These images help confirm that the inflammation has settled enough to safely operate or remove the seton [16].
Common questions in this guide
How long does a temporary seton stay in place before the second surgery?
Why would a seton need to stay in long-term?
How does a doctor know when it is time to remove a seton?
Can I live a normal life with a long-term seton?
Questions to Ask Your Doctor
Curated prompts to bring to your next appointment.
- 1.What specific healing milestones are you looking for before we can safely remove my seton?
- 2.Are we using this seton to prepare for a second surgery, or is the goal long-term symptom management?
- 3.If this is a temporary seton, which secondary procedure do you think is most appropriate for my anatomy to safely close the tract?
- 4.Will we be doing an MRI or ultrasound to check the fistula's progress before making the next treatment decision?
- 5.How frequently should I be coming into the office for you to check the seton and the drainage?
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References
References (16)
- 1
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Schiano di Visconte M, Bellio G
International journal of colorectal disease 2018; (33(12)):1723-1731 doi:10.1007/s00384-018-3154-z.
PMID: 30187158 - 2
Preventing the recurrence of acute anorectal abscesses utilizing a loose seton: a pilot study.
Erol T, Mentes B, Bayri H, et al.
The Pan African medical journal 2020; (35()):18 doi:10.11604/pamj.2020.35.18.21029.
PMID: 32341739 - 3
Treatment of Perianal Fistulas in Crohn's Disease, Seton Versus Anti-TNF Versus Surgical Closure Following Anti-TNF [PISA]: A Randomised Controlled Trial.
Wasmann KA, de Groof EJ, Stellingwerf ME, et al.
Journal of Crohn's & colitis 2020; (14(8)):1049-1056 doi:10.1093/ecco-jcc/jjaa004.
PMID: 31919501 - 4
Long-term outcomes after seton placement for perianal fistulas with and without Crohn's disease.
Motamedi MAK, Serahati S, Rajendran L, et al.
Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 2021; (23(9)):2407-2415 doi:10.1111/codi.15771.
PMID: 34157210 - 5
Ligation of the intersphincteric fistula fract (LIFT) in complex anorectal fistulas: retrospective analysis of the outcomes in a tertiary hospital.
Van De Putte D, Depuydt M, Colpaert J, Van Ramshorst GH
Updates in surgery 2025; (77(4)):1095-1104 doi:10.1007/s13304-025-02174-5.
PMID: 40335785 - 6
'Optimum' strategy and outcome in Crohn's anal fistula.
Lee MJ
Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 2023; (25(3)):495-496 doi:10.1111/codi.16389.
PMID: 36350257 - 7
The role of multimodal treatment in Crohn's disease patients with perianal fistula: a multicentre retrospective cohort study.
Sebastian S, Black C, Pugliese D, et al.
Alimentary pharmacology & therapeutics 2018; (48(9)):941-950 doi:10.1111/apt.14969.
PMID: 30226271 - 8
Anoperineal lesions in Crohn's disease: French recommendations for clinical practice.
Bouchard D, Abramowitz L, Bouguen G, et al.
Techniques in coloproctology 2017; (21(9)):683-691 doi:10.1007/s10151-017-1684-y.
PMID: 28929282 - 9
Distalization of perianal fistulas after loose silicone seton drainage is a myth.
Verkade C, van Tilborg GFAJB, Stijns J, et al.
Techniques in coloproctology 2023; (28(1)):16 doi:10.1007/s10151-023-02882-3.
PMID: 38097914 - 10
Predictive factors for recurrence of high transsphincteric anal fistula after placement of seton.
Emile SH, Elfeki H, Thabet W, et al.
The Journal of surgical research 2017; (213()):261-268 doi:10.1016/j.jss.2017.02.053.
PMID: 28601324 - 11
Timing of seton removal and clinical outcomes in perianal fistulizing Crohn's disease: A systematic review and meta-analysis.
Horio Y, Uchino M, Tomoo Y, et al.
Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 2026; (28(4)):e70449 doi:10.1111/codi.70449.
PMID: 42003433 - 12
Management of perianal fistula in inflammatory bowel disease: identification of prognostic factors associated with surgery.
de Las Casas SG, Alvarez-Gallego M, Martínez JAG, et al.
Langenbeck's archives of surgery 2021; (406(4)):1181-1188 doi:10.1007/s00423-021-02100-4.
PMID: 33515317 - 13
Comparison of the Efficacy of the Various Treatment Modalities in the Management of Perianal Crohn's Fistula: A Review.
Feroz SH, Ahmed A, Muralidharan A, Thirunavukarasu P
Cureus 2020; (12(12)):e11882 doi:10.7759/cureus.11882.
PMID: 33415035 - 14
Endoanal Ultrasound in Perianal Crohn's Disease.
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Journal of clinical medicine 2025; (14(19)) doi:10.3390/jcm14196867.
PMID: 41095946 - 15
How I Do It: MRI Approach to Perianal Fistulas.
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PMID: 42117990 - 16
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PMID: 41573455
This information is for educational purposes and does not replace professional medical advice. Always discuss your specific anal fistula treatment plan and seton timeline with your colorectal surgeon or gastroenterologist.
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