Percutaneous tibial nerve stimulation versus sham electrical stimulation for the treatment of faecal incontinence in adults (CONFIDeNT): a double-blind, multicentre, pragmatic, parallel-group, randomised controlled trial

Summary

Background

Percutaneous tibial nerve stimulation (PTNS) is a new ambulatory therapy for faecal incontinence. Data from case series suggest it has beneficial outcomes in 50–80% patients; however its effectiveness against sham electrical stimulation has not been investigated. We therefore aimed to assess the short-term efficacy of PTNS against sham electrical stimulation in adults with faecal incontinence.

Methods

We did a double-blind, multicentre, pragmatic, parallel-group, randomised controlled trial (CONtrol of Faecal Incontinence using Distal NeuromodulaTion [CONFIDeNT]) in 17 specialist hospital units in the UK that had the skills to manage patients with faecal incontinence. Eligible participants aged 18 years or older with substantial faecal incontinence for whom conservative treatments (such as dietary changes and pelvic floor exercises) had not worked, were randomly assigned (1:1) to receive either PTNS (via the Urgent PC neuromodulation system) or sham stimulation (via a transcutaneous electrical nerve stimulation machine to the lateral forefoot) once per week for 12 weeks. Randomisation was done with permuted block sizes of two, four, and six, and was stratified by sex and then by centre for women. Patients and outcome assessors were both masked to treatment allocation for the 14-week duration of the trial (but investigators giving the treatment were not masked). The primary outcome was a clinical response to treatment, which we defined as a 50% or greater reduction in episodes of faecal incontinence per week. We assessed this outcome after 12 treatment sessions, using data from patients' bowel diaries. Analysis was by intention to treat, and missing data were multiply imputed. This trial is registered with the ISRCTN registry, number 88559475, and is closed to new participants.

Findings

Between Jan 23, 2012, and Oct 31, 2013, we randomly assigned 227 eligible patients (of 373 screened) to receive either PTNS (n=115) or sham stimulation (n=112). 12 patients withdrew from the trial: seven from the PTNS group and five from the sham group (mainly because they could not commit to receiving treatment every week). Two patients (one in each group) withdrew because of an adverse event that was unrelated to treatment (exacerbation of fibromyalgia and rectal bleeding). 39 (38%) of 103 patients with full data from bowel diaries in the PTNS group had a 50% or greater reduction in the number of episodes of faecal incontinence per week compared with 32 (31%) of 102 patients in the sham group (adjusted odds ratio 1·28, 95% CI 0·72–2·28; p=0·396). No serious adverse events related to treatment were reported in the trial. Seven mild, related adverse events were reported in each treatment group, mainly pain at the needle site (four in PTNS, three in sham).

Interpretation

PTNS given for 12 weeks did not confer significant clinical benefit over sham electrical stimulation in the treatment of adults with faecal incontinence. Further studies are warranted to determine its efficacy in the long term, and in patient subgroups (ie, those with urgency).

Funding

National Institute for Health Research.

Introduction

Faecal incontinence is a substantial health problem with major effects on physical and emotional wellbeing. Quality of life for patients with this disorder is further reduced by psychological disability, stigmatisation, and social exclusion.¹ The prevalence and severity of faecal incontinence increases with age and it is a common cause of admission to residential care, where more than 50% of residents are affected.²

Management of faecal incontinence is challenging because of a widespread shortage of skills to deal with the disorder and the complex interaction of its causes. Patients for whom conservative management strategies (such as diet, bowel retraining, and drugs) do not work, often need surgical intervention.³ However, surgical procedures are invasive, have variable success rates, and are associated with a risk of significant morbidity.⁴

In view of these limitations of surgical approaches, the use of neuromodulation to treat faecal incontinence is now well established.⁵ Chronic, electrical stimulation of the sacral root (sacral nerve stimulation)5, 6 is now the first-line surgical intervention.³ This technique is safe, modifiable, and reversible, but needs two operations and has high direct equipment costs. Tibial nerve stimulation is a minimally invasive alternative to sacral nerve stimulation. Stimulation of the tibial nerve is thought to lead to similar changes in anorectal neuromuscular function as with sacral nerve stimulation because of shared sacral segmental innervation. It is an outpatient treatment, which makes it cheaper than sacral nerve stimulation. Of the two delivery methods of sacral nerve stimulation—percutaneous tibial nerve stimulation (PTNS) and transcutaneous tibial nerve stimulation—PTNS seems to have greater clinical effect.7, 8, 9

Research in context

Evidence before this study

Percutaneous tibial nerve stimulation (PTNS) is a new neuromodulatory therapy for faecal incontinence. We did a systematic review of tibial nerve stimulation (TNS) outcomes for the treatment of faecal incontinence of studies published from Jan 1, 2003, to Nov 1, 2014, with the search terms “tibial nerve stimulation faecal incontinence”, “tibial nerve”, “tibial nerve stimulation”, “faecal incontinence”, and “fecal incontinence”, with no language restrictions. Included studies could be of any design but should have provided selected review outcome data (both baseline and post intervention) for at least ten patients. No exclusions were placed on study centre or patients, in terms of age, sex, ethnic origin, or cause of faecal incontinence. We identified 20 eligible studies, 13 of which studied PTNS. These included ten case series of PTNS, a comparative case matched study of PTNS versus sacral nerve stimulation (SNS), a prospective clinical audit of SNS and PTNS, and a randomised study of PTNS versus transcutaneous tibial nerve stimulation versus sham. From these studies, the success rate of PTNS in the treatment of faecal incontience (with the same primary outcome as the CONFIDeNT Trial) ranged from 52 to 82%.

Added value of this study

We did a multicentre, parallel-group, double-blind, randomised controlled trial of 227 patients with faecal incontinence who were given either PTNS or sham electrical stimulation. The trial did not meet the primary outcome: 39 (38%) patients in the PTNS group had a 50% or greater reduction in episodes of faecal incontinence per week compared with 32 (31%) in the sham group (OR 1·28, 95% CI 0·72–2·28, p=0·396). No serious adverse events related to treatment were reported.

Implications of all the available evidence

The results of this study suggest that PTNS does not have significant clinical benefit over sham electrical stimulation for the patient population studied. This information is contrary to previous observational data from systematic reviews and might change practice and policy. Further studies are needed to establish the efficacy of PTNS in the long term and within specific subgroups; eg, patients with urgency. Health-service research could also identify how PTNS promotes or contributes to other mixed packages of nurse-led care.

Data from six case series of PTNS, and one randomised trial, including a total of 371 patients⁷ have shown improvements in several clinical outcome measures (bowel diary, summative symptom scores, and quality of life) compared with baseline results, leading to clinical success in 62–83% patients in the short-term. However, the outcome of PTNS versus sham stimulation has not been compared in a large, adequately powered, multicentre randomised trial. In this study (CONtrol of Faecal Incontinence using Distal NeuromodulaTion [CONFIDeNT]), we aimed to compare the short-term efficacy of PTNS versus sham electrical stimulation in adults with faecal incontinence.