Double-blind randomised controlled trial of percutaneous tibial nerve stimulation versus sham electrical stimulation in the treatment of faecal incontinence: CONtrol of Faecal Incontinence using Distal NeuromodulaTion (the CONFIDeNT trial)

Background: Faecal incontinence (FI) is a common condition which is often under-reported. It is distressing for those suffering from it, impacting heavily on their quality of life. When conservative strategies fail, treatment options are limited. Percutaneous tibial nerve stimulation (PTNS) is a minimally invasive outpatient treatment, shown in preliminary case series to have significant effectiveness; however, no randomised controlled trial has been conducted. Objectives: To assess the effectiveness of PTNS compared with sham electrical stimulation in the treatment of patients with FI in whom initial conservative strategies have failed. Design: Multicentre, parallel-arm, double-blind randomised (1 : 1) controlled trial. Setting: Eighteen UK centres providing specialist nurse-led (or equivalent) treatment for pelvic floor disorders. Participants: Participants aged > 18 years with FI who have failed conservative treatments and whose symptoms are sufficiently severe to merit further intervention. Interventions: PTNS was delivered via the Urgent® PC device (Uroplasty Limited, Manchester, UK), a hand-held pulse generator unit, with single-use leads and fine-needle electrodes. The needle was inserted near the tibial nerve on the right leg adhering to the manufacturer’s protocol (and specialist training). Treatment was for 30 minutes weekly for a duration of 12 treatments. Validated sham stimulation involved insertion of the Urgent PC needle subcutaneously at the same site with electrical stimulation delivered to the distal foot using transcutaneous electrical nerve stimulation. Main outcome measures: Outcome measures were assessed at baseline and 2 weeks following treatment. Clinical outcomes were derived from bowel diaries and validated, investigator-administered questionnaires. The primary outcome classified patients as responders or non-responders, with a responder defined as someone having achieved ≥ 50% reduction in weekly faecal incontinence episodes (FIEs). Results: In total, 227 patients were randomised from 373 screened: 115 received PTNS and 112 received sham stimulation. There were 12 trial withdrawals: seven from the PTNS arm and five from the sham arm. Missing data were multiply imputed. For the primary outcome, the proportion of patients achieving a ≥ 50% reduction in weekly FIEs was similar in both arms: 39 in the PTNS arm (38%) compared with 32 in the sham arm (31%) [odds ratio 1.28, 95% confidence interval (CI) 0.72 to 2.28; p = 0.396]. For the secondary outcomes, significantly greater decreases in weekly FIEs were observed in the PTNS arm than in the sham arm (beta –2.3, 95% CI –4.2 to –0.3; p = 0.02), comprising a reduction in urge FIEs (p = 0.02) rather than passive FIEs (p = 0.23). No significant differences were found in the St Mark’s Continence Score or any quality-of-life measures. No serious adverse events related to treatment were reported. Conclusions: PTNS did not show significant clinical benefit over sham electrical stimulation in the treatment of FI based on number of patients who received at least a 50% reduction in weekly FIE. It would be difficult to recommend this therapy for the patient population studied. Further research will concentrate on particular subgroups of patients, for example those with pure urge FI. Trial registration: Current Controlled Trials ISRCTN88559475. Funding: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 77. See the NIHR Journals Library website for further project information.