An interventional study of Mechanical bowel preparation in Anal Fistula, Rectal Fistula and Crohn Disease, sponsored by Region Skane. Not yet recruiting at 1 site in Sweden. Open to participants aged 18 Years to 64 Years. Per ClinicalTrials.gov, last updated 2026-10-27.
Sponsored by Region Skane · Not applicable, Interventional, and Treatment
The goal of this clinical trial is to learn whether bowel preparation with Plenvu before surgery improves healing of complex anal fistula in adults aged 18 to 64 years with a fistula of cryptoglandular origin or associated with Crohn's disease.
The main question it aims to answer is:
- Does bowel preparation before surgery increase the proportion of participants whose fistula is clinically healed 6 months after surgery?
Researchers will compare participants who prepare the bowel before surgery with participants who receive no bowel preparation. All participants receive the same oral antibiotic regimen and one of three standard sphincter-preserving operations: ligation of the intersphincteric fistula tract (LIFT), autologous platelet-rich fibrin (Obsidian), or endorectal advancement flap. The operation is chosen individually by the surgeon as the most appropriate for each fistula, before randomisation.
Participants will:
Background Surgery for anal fistula aims to close the fistula while preserving continence, and healing rates after sphincter-preserving techniques vary widely. Current guidelines (ESCP 2024) give no recommendation on bowel preparation before anal fistula surgery, and no randomised evidence exists on its effect on fistula healing. The hypothesis is that emptying the bowel before surgery delays the first postoperative bowel movement and reduces faecal contamination of, and mechanical strain on, the repair during early healing.
Design Single-centre, open-label, randomised controlled trial with two parallel arms and 1:1 allocation. The surgical technique (LIFT, autologous platelet-rich fibrin [Obsidian] or endorectal advancement flap) is chosen individually by the surgeon as the most appropriate for each fistula, and documented before randomisation. Allocation is computer-generated using permuted blocks stratified by surgical technique. Each participant undergoes one fistula operation within the study.
Interventions Experimental arm: mechanical bowel preparation with Plenvu, two doses taken the evening before surgery. Control arm: no bowel preparation. Both arms receive a single oral dose of trimethoprim/sulfamethoxazole 160/800 mg and a single oral dose of metronidazole 1.2 g before surgery, and otherwise identical perioperative care.
Follow-up Participants are assessed at baseline and at 6 and 12 months after surgery. Baseline data include age, sex, height, weight, body mass index, smoking, diabetes, cardiovascular, pulmonary, renal and chronic inflammatory disease, albumin, haemoglobin, C-reactive protein, ongoing immunosuppressive treatment, fistula aetiology, Parks classification and previous fistula surgery. For participants with Crohn's disease, the Montreal classification and the Perianal Disease Activity Index (PDAI) are recorded.
Blinding Participants and surgeons are not blinded. Clinical healing is assessed by the surgical team, who are aware of allocation.
Sample size A total of 116 participants (58 per arm) is planned to detect an absolute difference of 25 percentage points in clinical healing at 6 months, with an alpha of 0.05 and a power of 80%, allowing for 10% loss to follow-up.
Statistical analysis Dichotomous Variables (Healing Rates): The overall proportion of healed patients between groups will be compared using a Chi-square test. A multivariable logistic regression model will be used to adjust for the surgery type stratum. The treatment effect will be reported as an odds ratio (OR) alongside 95% confidence intervals.
Continuous Variables (Score Changes): Changes in continuous scores from baseline will be evaluated using a multiple linear regression model. The model will compare the mean differences between the two treatment groups while adjusting for baseline scores and the stratum of the surgery type. If the assumptions of linear regression are strictly violated, appropriate data transformations or nonparametric alternatives will be applied.
Missing data: To strictly adhere to the intention-to-treat (ITT) principle, all randomised participants will be included in the final analysis in their originally assigned groups. To handle missing data, Multiple Imputation (MI) may be utilised as the primary analytical approach, but a complete case analysis will also be conducted. The imputation model would include the stratification variable (surgery type), baseline scores, and available intermediate follow-up data.
169 studies on the registry are indexed under Rectal Fistula; 45 are open to participants now.
This study's planned enrollment of 116 is above the median of 66 across 115 interventional studies indexed under Rectal Fistula.
Browse Rectal Fistula studies →Region Skane is the lead sponsor of 386 studies on the registry; 122 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Mechanical bowel preparation with Plenvu before surgery. All participants receive the same oral antibiotic regimen. Participants then undergo LIFT, platelet-rich fibrin (Obsidian) or endorectal advancement flap, chosen individually for each fistula before randomisation.
Procedure: Mechanical bowel preparation
No preoperative bowel preparation. All participants receive the same oral antibiotic regimen. Participants then undergo LIFT, platelet-rich fibrin (Obsidian) or endorectal advancement flap, chosen individually for each fistula before randomisation.
Oral bowel cleansing with Plenvu before surgery used within its marketing authorisation.
Fistula Healing Rate at 6 Months Post-Surgery
Percentage of participants with clinical fistula healing, defined as complete closure of the external opening with no discharge on clinical examination, assessed by the surgical team (not blinded to allocation).
Time frame: 6 months post-surgery
Fistula Healing Rate at 12 Months Post-Surgery
Percentage of participants with clinical fistula healing, defined as complete closure of the external opening with no discharge on clinical examination, assessed by the surgical team (not blinded to allocation).
Time frame: 12 Months Post-Surgery
Radiological Fistula Healing Rate on 3D Endoanal Ultrasound at 12 Months Post-Surgery
Percentage of participants with radiological fistula healing on 3D endoanal ultrasound, defined as the replacement of the previous fistulous tract with homogeneous tissue of intermediate echogenicity.
Time frame: 12 Months Post-Surgery
Change in St Mark's Incontinence Score
St Mark's (Vaizey) incontinence score, range 0-24; higher scores indicate worse incontinence.
Time frame: Baseline, 6 and 12 months post-surgery
Postoperative Complications Measured by the Comprehensive Complication Index (CCI)
CCI summarises all complications graded by Clavien-Dindo; range 0-100, higher scores indicate more severe cumulative morbidity.
Time frame: 30 days after surgery
Change in Quality of Life Measured by the QoLAF-Q
Quality of Life in Patients with Anal Fistula Questionnaire (QoLAF-Q): 14 items on a 5-point Likert scale, total score 14-70; higher scores indicate greater impact of the fistula on quality of life.
Time frame: Baseline, at 6 and 12 months post-surgery
Change in Perianal Disease Activity Index (PDAI) in Participants With Crohn's Disease
PDAI, range 0-20; higher scores indicate more active perianal disease.
Time frame: Baseline, 6 and 12 months post-surgery
Plan to share: No — Individual participant data will not be shared outside the research group, as the ethical approval and participant consent do not cover such sharing under the GDPR and Swedish law.
Start is estimated for Nov 2026; primary completion for May 2028, 18 months later.
Of 53 non-industry interventional studies with no phase under Rectal Fistula, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 36. This study's planned 18 months is below that.
Counting every sponsor, half of 57 studies reached it within 27 months; a quarter within 11 and three quarters within 38.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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