Evidence map›Paper›PMID 42838583›Full record

ArticleBMJ open2026

Does omission of a loose seton before sphincter-preserving surgery achieve non-inferior fistula closure compared with routine loose seton placement in adults with single-tract cryptoglandular anal fistula in the Netherlands?

Ahmed A Elwakel, Pieter Van Hagen, Ruben Veldkamp, Susan van Dieren, Willem A Bemelman, Ingrid J M Han-Geurts, SETON projectgroup

Abstract readClinical Trial Protocol
In one paragraph

Article in BMJ open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Ahmed A ElwakelDepartment of Surgery, Amsterdam UMC, Amsterdam, The Netherlands a.elwakel@amsterdamumc.nl.ORCID http://orcid.org/0009-0001-3836-0429
Pieter Van HagenDepartment of Surgery, Proctos Kliniek, Bilthoven, The Netherlands.
Ruben VeldkampDepartment of Surgery, Proctos Kliniek, Bilthoven, The Netherlands.
Susan van DierenDepartment of Surgery, Amsterdam UMC, Amsterdam, The Netherlands.
Willem A BemelmanDepartment of Surgery, Amsterdam UMC, Amsterdam, The Netherlands.
Ingrid J M Han-GeurtsDepartment of Surgery, Proctos Kliniek, Bilthoven, The Netherlands.
SETON projectgroup

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionCryptoglandular anal fistulas are burdensome, often recurrent and frequently treated in two stages using a loose seton before definitive sphincter-preserving surgery. Although this practice is common, high-quality evidence supporting improved healing or functional outcomes is lacking. A trial is needed to determine whether omitting routine seton placement can reduce procedures, patient burden and costs without compromising fistula closure. METHODS AND ANALYSIS: The SETON trial is a multicentre, randomised, unblinded non-inferiority trial with an integrated cost-utility analysis. Adults with a single-tract non-purulent mid-high or high cryptoglandular anal fistula will be randomised to loose seton placement for 8 weeks followed by definitive sphincter-preserving surgery, or to direct sphincter-preserving surgery without prior seton placement. The primary endpoint is fistula closure 26 weeks after final surgery, defined clinically and if needed confirmed by MRI or endoanal ultrasound. Secondary outcomes include recurrence, postoperative complications, pain, re-interventions, continence, fistula-related quality of life, generic health-related quality of life, return to work and cost-effectiveness. A sample size has been calculated for a non-inferiority design with fistula closure at 26 weeks as the primary endpoint. Assuming a conservative closure rate of 60% in the standard-care seton group, a one-sided alpha of 0.05, 80% power and a non-inferiority margin of 15 percentage points, 126 patients are required per group for analysis. Allowing for approximately 10% loss to follow-up, the total sample size will be 277 patients. Data will be analysed according to the intention-to-treat and per-protocol principle. ETHICS AND DISSEMINATION: The protocol has been approved by the Medical Ethics Review Committee of the Amsterdam University Medical Center, location AMC (reference number: 2025.0826-NL-010338 R031541). Findings will be disseminated in peer-reviewed journals and presented at conferences, whether they are positive, negative or inconclusive. TRIAL REGISTRATION NUMBER: NL-010338.

Indexed as

Anal CanalRectal FistulaAdultColorectal Surgical ProceduresCost-Benefit AnalysisEquivalence Trials as TopicHumansMulticenter Studies as TopicNetherlandsQuality of LifeRandomized Controlled Trials as TopicTreatment OutcomeAdult surgeryColorectal surgerySURGERY

Identifiers

PMID42838583
PMCPMC13646918

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.