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Pragmatic Clinical Trials Unit

SUBSoNIC

Full Title: Randomised double-blind efficacy and mechanism study of sub-sensory sacral (optimised) neuromodulation in adults with faecal incontinence  

Chief Investigator: Professor Charles Knowles

Funder: NIHR Efficacy and Mechanism Evaluation (EME) Programme/ Medtronic Inc

Funder Reference: 14/144/08

Research Status: Recruiting

Faecal incontinence is defined as the involuntary loss of stool or wind leading to a social or hygienic problem. It affects 1 in 10 people in the community, up to 3 in 10 people in the hospital, and up to 7 in 10 people in nursing homes. It can lead to negative effects on quality of life in terms of physical and emotional health. Treatment of faecal incontinence starts with drugs (usually loperamide), behavioural therapies and pelvic floor physiotherapy. When these therapies have failed, surgical treatment is considered as the next step.

 A relatively new surgical treatment called sacral neuromodulation (SNM) is now commonly offered to adults suffering with faecal incontinence. Suitable patients include those with faecal incontinence caused by childbirth, surgery, and advancing age. A battery powered unit is implanted into the lower back in the region of the sacrum (tailbone). This is connected to a specially developed lead with electrodes which rest on the nerves in the lower spine (most commonly the third sacral nerve). This stimulator then continuously sends electrical impulses to the nerves and muscles that control the lower bowel (rectum and anus). The result may improve continence.

 Previous studies have reported a great benefit of SNM in some patients. Unfortunately, other patients can have little or no response. We are still unsure about how SNM restores bowel control. And we still do not know with certainty how effective SNM really is. SNM costs on average £10,000 per patient just for the equipment and while a very safe therapy in comparison with other surgery, SNM still has some risks e.g. infection and unwanted side-effects. It is therefore vital that these questions are answered.

 This research aims to establish how SNM works and how well SNM works. Patients who meet the current national criteria for SNM will be invited to participate in our trial. They will undergo detailed evaluation of their symptoms. Some will also undergo specialist tests before and after treatment. These will study their anal and rectal function as well as their corresponding brain activity (using a special test called magnetoencephalography).

 In contrast to a traditional clinical trial, the design of this trial will allow all patients to receive the treatment. This is possible by using a crossover design i.e. one where after implantation of the stimulator all patients receive a period of real therapy (SNM: device on but at an unperceived level of stimulation) compared to a period of sham (placebo) therapy. The effects of SNM can then be compared while both the patients and the research team are unaware whether the stimulation is SNM or sham. This is called ‘double-blinding’ and is the gold standard for determining what the true effects of the treatment are.

 The study will be led by Barts Health NHS Trust and Queen Mary University of London. It will be performed in several NHS specialist centres and at the Aston Brain Centre (Birmingham). The trial will include a total of 90 patients. Each patient will participate for just over 12 months, but their SNM treatment will continue thereafter.

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