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Randomized clinical trial of percutaneous tibial nerve stimulation versus sham electrical stimulation in patients with faecal incontinence. BJS 2017; 104: 1167-1176.

Published: 13th July 2017

Authors: A. A. van der Wilt, G. Giuliani, C. Kubis, B. P. W. van Wunnik, I. Ferreira, S. O. Breukink et al.

Background

The aim was to assess the effects of percutaneous tibial nerve stimulation (PTNS) in the treatment of faecal incontinence (FI) by means of an RCT.

Method

Patients aged over 18 years with FI were included in a multicentre, single‐blinded RCT. The primary endpoint was reduction in the median or mean number of FI episodes per week. Secondary endpoints were changes in measures of FI severity, and disease‐specific and generic quality of life. Outcomes were compared between PTNS and sham stimulation after 9 weeks of treatment.

Results

A higher proportion of patients in the PTNS (13 of 29) than in the sham (6 of 30) group showed a reduction of at least 50 per cent in the median number of FI episodes/week (incidence rate ratio (IRR) 2·40, 95 per cent c.i. 1·10 to 5·24; P = 0·028), but not in the mean number of episodes/week (10 of 29 versus 8 of 30; IRR 1·42, 0·69 to 2·92; P = 0·347). The absolute median number of FI episodes per week decreased in the PTNS but not in the sham group (IRR 0·66, 0·44 to 0·98; P = 0·041), as did the mean number (IRR 0·65 (0·45 to 0·97); P = 0·034). Scores on the Cleveland Clinic Florida faecal incontinence scale decreased significantly in both groups, but more steeply in the PTNS group (mean difference –1·3, 95 per cent c.i. –2·6 to 0·0; P = 0·049). The aggregated mental component score of Short Form 36 improved in the PTNS but not in the sham group (mean difference 5·1, 0·5 to 9·6; P = 0·028).

Conclusion

PTNS may offer a small advantage in the clinical management of FI that is insufficiently responsive to conservative treatment. The key challenge will be to identify patients who may benefit most from this minimally invasive surgical procedure. Registration number: NCT00974909 (http://www.clinicaltrials.gov).

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Your comments

1 Comment

Osman Chaudhary

2 months ago

We read with interest and congratulate the authors on their multi-centre, randomized controlled trial to improve our understanding of where PTNS fits in the management of faecal incontinence.

Sham-stimulation, used in this study as control, is problematic. Omission of such a control may lead to a degree of patient “unblinding”. Conversely, sham-stimulation in itself produces artefact and bias.

The location of sham-stimulation corresponds to a well-known acupuncture point (sanyinjiao, SP6). Acupuncture has been reported to significantly improve faecal incontinence (1,2). Insertion of a needle releases endogenous opioid peptides which may lead to C-fibre activation through local neural mechanisms (3,4).

We welcome the authors’ comments on whether anatomical landmarks or electrical stimulation aided in the “correct positioning of the needle electrode”. Could the needle insertion in SP6 have contributed to the improvement of mean episodes of incontinence per week within the sham-stimulation group?

We would be interested if any sub group analysis of patients with rectal evacuatory dysfunction was performed. There is evidence to support PTNS produces a significant improvement in symptoms of both passive and urge incontinence (5). In our experience, patients with rectal evacuatory dysfunction, however, appear less likely to respond to electrical neurostimulation (unpublished data).

Osman Chaudhary
Christopher Chan

Royal London Hospital
Whitechapel Rd
London E1 1BB, UK
osmanchaudhary82@gmail.com

References:
1. Scaglia M, Delaini G, Destefano I, Hulten L. Fecal incontinence treated with acupuncture–a pilot study. Auton Neurosci 2009; 145: 89-92.
2. Franco JT, Agulhon AM, Viani FC, Viebig RG. Systemic acupuncture in patients with faecal incontinence. Complement Ther Clin Pract 2016; 24: 162-6.
3. Kawakita K, Okada K. Acupuncture therapy: mechanism of action, efficacy, and safety: a potential intervention for psychogenic disorders? Biopsychosoc Med 2014; 8: 4.
4. Hashimoto T, Akita H, Aikawa S. Analgesia induced by manual acupuncture: its potency and implication. Kitasato Arch Exp Med 1993; 65: 73-82.
5. Hotouras A, Thaha MA, Boyle DJ, Allison ME, Currie A, Knowles CH, Chan CL. Short-term outcome following percutaneous tibial nerve stimulation for faecal incontinence: a single-centre prospective study. Colorectal Dis 2012; 14: 1101-5.