Efficacy and mechanism of sub-sensory sacral (optimised) neuromodulation in adults with faecal incontinence:Study protocol for a randomised controlled trial


Background: Faecal incontinence (FI) is a substantial health problem with a prevalence of approximately 8% in community-dwelling populations. Sacral neuromodulation (SNM) is considered the first-line surgical treatment option in adults with FI in whom conservative therapies have failed. The clinical efficacy of SNM has never been rigorously determined in a trial setting and the underlying mechanism of action remains unclear. Methods/design: The design encompasses a multicentre, randomised, double-blind crossover trial and cohort follow-up study. Ninety participants will be randomised to one of two groups (SNM/SHAM or SHAM/SNM) in an allocation ratio of 1:1. The main inclusion criteria will be adults aged 18-75 years meeting Rome III and ICI definitions of FI, who have failed non-surgical treatments to the UK standard, who have a minimum of eight FI episodes in a 4-week screening period, and who are clinically suitable for SNM. The primary objective is to estimate the clinical efficacy of sub-sensory SNM vs. SHAM at 32 weeks based on the primary outcome of frequency of FI episodes using a 4-week paper diary, using mixed Poisson regression analysis on the intention-to-treat principle. The study is powered (0.9) to detect a 30% reduction in frequency of FI episodes between sub-sensory SNM and SHAM stimulation over a 32-week crossover period. Secondary objectives include: measurement of established and new clinical outcomes after 1 year of therapy using new (2017 published) optimised therapy (with standardised SNM-lead placement); validation of new electronic outcome measures (events) and a device to record them, and identification of potential biological effects of SNM on underlying anorectal afferent neuronal pathophysiology (hypothesis: SNM leads to increased frequency of perceived transient anal sphincter relaxations; improved conscious sensation of defaecatory urge and cortical/subcortical changes in afferent responses to anorectal electrical stimulation (main techniques: high-resolution anorectal manometry and magnetoencephalography). Discussion: This trial will determine clinical effect size for sub-sensory chronic electrical stimulation of the sacral innervation. It will provide experimental evidence of modifiable afferent neurophysiology that may aid future patient selection as well as a basic understanding of the pathophysiology of FI.

Publication DOI: https://doi.org/10.1186/s13063-018-2689-1
Divisions: College of Health & Life Sciences
College of Health & Life Sciences > Clinical and Systems Neuroscience
College of Health & Life Sciences > Aston Institute of Health & Neurodevelopment (AIHN)
College of Health & Life Sciences > School of Psychology
Additional Information: © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Uncontrolled Keywords: Anorectal manometry,Evoked potential,Faecal incontinence,Magneticoencepholograpy,Randomised controlled trial,Sacral nerve stimulation,Sacral neuromodulation,Medicine (miscellaneous),Pharmacology (medical)
Publication ISSN: 1745-6215
Last Modified: 06 May 2024 07:25
Date Deposited: 16 Jul 2018 12:31
Full Text Link:
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://trialsj ... 3063-018-2689-1 (Publisher URL)
PURE Output Type: Article
Published Date: 2018-06-26
Accepted Date: 2018-05-16
Authors: McAlees, Eleanor
Vollebregt, Paul F.
Stevens, Natasha
Dudding, Tom C.
Emmanuel, Anton V.
Furlong, Paul L. (ORCID Profile 0000-0002-9840-8586)
Hamdy, Shaheen
Hooper, Richard L.
Jones, James F.X.
Norton, Christine
O'Connell, P. Ronan
Scott, S. Mark
Knowles, Charles H.



Version: Published Version

License: Creative Commons Attribution

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