Evidence
Alert

Percutaneous tibial nerve stimulation is of limited benefit for faecal incontinence

People with faecal incontinence did not obtain any important benefits from receiving percutaneous tibial nerve stimulation compared with a sham treatment. The treatment involves stimulating the nerves that control bowel function by passing a mild electric current through a fine needle, inserted just above the ankle.

This NIHR-funded trial specified a difference in the number of people having at least 50% fewer episodes of faecal incontinence per week as their main outcome, and on this measure there was no significant difference. The treatment did cause a small but statistically significant difference in the number of episodes of incontinence per week (two fewer) but as patients remained incontinent this was thought to be less important to them. Nerve stimulation seemed to be more effective for people who had urge faecal incontinence, where there is a sudden need followed by incontinence.

As the effectiveness of percutaneous tibial nerve stimulation in this study was minimal, it is unlikely to be recommended over sacral nerve stimulation. More focussed research to identify sub-groups of sufferers who may benefit, like those with urge incontinence, might be useful.

Why was this study needed?

People with faecal incontinence cannot control their bowel movements, resulting in soiling. It affects around 1 in 10 people at some point in their life, although it is more common in older people. It has a big effect on people’s emotional well-being and may lead to social isolation, as they do not want to be far from toilet facilities or risk soiling in public.

Conservative treatments such as changes to diet, pelvic floor exercises and medication are usually tried before considering surgical options. One of the surgical options is sacral nerve stimulation, although this is expensive because of the cost of the device and the operation to implant it. Percutaneous tibial nerve stimulation may offer a non-surgical alternative. The tibial nerve is stimulated by an electrical current delivered by a small needle inserted into the skin behind the ankle.

Previous observational studies including ten case series and a randomised trial showed that the success rate of percutaneous tibial nerve stimulation in the treatment of faecal incontinence (with the same primary outcome as the current study) ranged from 52 to 82%. Observational studies, however, may not give a true picture due to unintentional bias in patient assignment or the observers’ assessments.

The NIHR funded this randomised controlled trial to compare the effectiveness of percutaneous tibial nerve stimulation against a sham treatment.

What did this study do?

The trial randomly assigned 227 people, aged 18 or over with faecal incontinence that had not improved with conservative treatment, to receive either percutaneous tibial nerve stimulation or sham treatment. Nerve stimulation and sham treatments were repeated weekly for 30 minutes over 12 weeks.

The sham treatment was transcutaneous electrical nerve stimulation. Both groups had electrodes for both treatments placed on their feet and then covered with a drape (so that they were blind to which treatment they were receiving). For percutaneous tibial nerve stimulation there was an electrode on the sole of the foot and a needle through the skin near the ankle – next to the tibial nerve – to send electrical impulses up the nerve. For transcutaneous electrical nerve stimulation there were pads on the opposite side of the foot. The percutaneous tibial nerve stimulation treatment group had stimulation of the tibial nerve but no transcutaneous electrical nerve stimulation while the sham group had transcutaneous electrical nerve stimulation but no tibial nerve stimulation.

What did it find?

  • Looking for a reduction of 50% in the number of incontinent episodes, there was no significant difference between groups. This was achieved by 38% who received tibial nerve stimulation and 31% in the sham group (adjusted odds ratio 1.28, 95% confidence interval [CI] 0.72 to 2.28).
  • There was an average of two fewer episodes of incontinence per week amongst those receiving tibial nerve stimulation, compared with sham treatment (average [mean] difference of ‑2.26 episodes, 95% CI ‑4.19 to ‑0.34). There were also fewer episodes of urge faecal incontinence (‑1.46, 95% CI ‑2.69 to ‑0.22), but no difference in passive faecal incontinence (‑0.64, 95% CI ‑1.67 to ‑0.40).
  • There were no significant differences in general or disease-specific quality of life between those receiving tibial nerve stimulation and those receiving sham treatment. Patient-reported outcomes were slightly better amongst those people receiving tibial nerve stimulation, but not for patients’ global impression of success.

What does current guidance say on this issue?

The 2007 NICE guideline recommends that faecal incontinence is managed using conservative treatments, if these treatments are unsuccessful, then the person is referred to specialist care and surgery can be considered. Faecal incontinence is a symptom of multiple conditions; therefore, the type of surgery depends on the cause of the faecal incontinence. Nerve stimulation is used in people who have an intact but weak sphincter. Sacral nerve stimulation is approved for use in the UK, whereas NICE’s 2011 guideline recommends percutaneous tibial nerve stimulation only as part of a research study.

What are the implications?

This study indicates that percutaneous tibial nerve stimulation is unlikely to be helpful for most people experiencing faecal incontinence. The finding that percutaneous tibial nerve stimulation was slightly more effective in reducing urge faecal incontinence indicates that this group of people may be worth further study.

Though percutaneous tibial nerve stimulation is less invasive and less costly than sacral nerve stimulation, this trial does not show that it was effective enough compared to a sham treatment to recommend it over sacral nerve stimulation.

 

Citation and Funding

Knowles CH, Horrocks EJ, Bremner SA, et al; CONFIDeNT study group. 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. Lancet. 2015;386(10004):1640-8.

This project was funded by the National Institute for Health Research Health Technology Assessment programme (project number 09/104/16).

 

Bibliography

NHS Choices. Bowel incontinence. London: NHS Choices; 2015.

NICE. Faecal incontinence in adults: management. CG49. London: National Institute for Health and Care Excellence; 2007.

NICE. Percutaneous tibial nerve stimulation for faecal incontinence. IPG395. London: National Institute for Health and Care Excellence; 2011.

NICE. Sacral nerve stimulation for faecal incontinence. IPG99. London: National Institute for Health and Care Excellence; 2004.

RCS. Commissioning guide: faecal incontinence. London: Royal College of Surgeons of England; 2014.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

 

Definitions

During percutaneous tibial nerve stimulation, a fine needle is inserted into the tibial nerve just above the ankle and an electrode is placed on the foot. The tibial nerve runs from the ankle to the pelvic floor. A mild electric current is passed through the needle to stimulate the tibial nerve. The exact mechanism of how the treatment works is not known.

The treatment usually consists of 12 outpatient sessions, each lasting about half an hour, once a week.

 

Commentaries

Author commentary

This pragmatic randomised controlled trial found that percutaneous tibial nerve stimulation has no benefit over sham electrical stimulation for treating faecal incontinence. Previous, mostly observational research, suggested a considerably higher treatment effect. Whilst this trial helps clarify the effectiveness of tibial nerve stimulation, it should not spell the end of its use, since some patients clearly do benefit. Further research is required into patient subgroups that may benefit. Unfortunately, clinical research into faecal incontinence faces heterogeneity at every point; there is a lack of agreement on definition for faecal incontinence, or treatment protocol, or the best outcome measure. Perhaps international agreement in these areas would help progress research on this topic?

Emma Horrocks, Clinical Research Fellow to Professor Charles Knowles, National Centre for Bowel Research and Surgical Innovation (NCBRSI), London