Clinical efficacy of subsensory sacral neuromodulation in adults with faecal incontinence: the SUBSoNIC crossover randomised controlled trial and cohort follow-up study
Vollebregt, Paul F Goh, Yan Li Bagul, Anil Chan, Claire Dudding, Tom Furlong, Paul Hamdy, Shaheen Haviland, Joanne Hooper, Richard Jones, James
Vollebregt, Paul F
Goh, Yan Li
Bagul, Anil
Chan, Claire
Dudding, Tom
Furlong, Paul
Hamdy, Shaheen
Haviland, Joanne
Hooper, Richard
Jones, James
Affiliation
Queen Mary University of London; Amsterdam University Medical Centre; Sandwell and West Birmingham NHS Trust; University Hospitals Birmingham NHS Foundation Trust; University Hospital Southampton NHS Foundation Trust; Aston University; University of Manchester; University College Dublin; King's College London; St Vincent's University Hospital; Cambridge University Hospitals NHS Foundation Trust; Cleveland Clinic London
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Publication date
2025-11-11
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Abstract
Aim: Sacral neuromodulation (SNM) is considered the first-line surgical treatment in adults with refractory faecal incontinence (FI). However, its clinical efficacy has not been rigorously tested in a trial setting.
Method: Randomised, multicentre, double-blind crossover trial (two 16-week periods) of active stimulation versus sham, and open-label follow-up to 58 weeks.
Participants: adults aged 18-80 with refractory FI.
Interventions: Active: subsensory sacral nerve stimulation with an implanted pulse generator; Sham: identical implant but turned off.
Primary outcome: FI episodes per week (paper bowel diary) during final 4 weeks of crossover periods (allowing 12 weeks' washout). Randomised allocation (1:1) to arm 1 (SNM/sham) or arm 2 (sham/SNM).
Blinding: participants, surgeons, assessors; tamper-proof tape-masked stimulation settings.
Sample size: 80 patients to detect a 30% reduction in episodes. Groups compared using a paired t-test, and treatment effects summarised by mean differences.
Results: Trial delivery was severely affected by COVID-19. Thirty-nine patients of 220 screened (arm 1: N = 17; arm 2: N = 22) were recruited at 10 sites (February 2018-July 2022), of whom only 16 (arm 1: N = 9; arm 2: N = 7) had complete primary outcome data. Of the 39, 19 completed follow-up to 58 weeks. SNM conferred a non-significant reduction in mean FI episodes per week compared to sham (-0.795 [95% CI: -1.5 to 0.0], p = 0.06). Improvements were observed in FI symptoms at 58 weeks compared to baseline (FI episodes per week: 3.2 [SD 3.3] vs. 6.2 [SD 5.9]).
Conclusions: The SUBSoNIC trial failed to find conclusive evidence of the experimental efficacy of SNM. Further demonstration of experimental efficacy remains important as SNM is a high-cost and invasive therapy.
Citation
Vollebregt PF, Goh YL, Bagul A, Chan C, Dudding T, Furlong P, Hamdy S, Haviland J, Hooper R, Jones J, McAlees E, Norton C, O'Connell PR, Powar M, Scott SM, Stevens N, Tubby K, Worthen S, Wong YL, Knowles CH. Clinical efficacy of subsensory sacral neuromodulation in adults with faecal incontinence: The SUBSoNIC crossover randomised controlled trial and cohort follow-up study. Colorectal Dis. 2025 Nov;27(11):e70308. doi: 10.1111/codi.70308.
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Article