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Study Authors: Judith S. Moore, Peter R. Gibson, Rebecca E. Burgell

Target Audience and Goal Statement: Gastroenterologists

The goal of this study was to assess the effects of transabdominal interferential electrical stimulation (TES) versus sham stimulation in women with functional constipation.

Question Addressed:

• What were the outcomes with TES versus sham stimulation in women with functional constipation?

Study Synopsis and Perspective:

Pain, tremor, and spasticity are among the numerous conditions amenable to neuromodulation. Recently, neuromodulation has also gained traction as a treatment for functional gastrointestinal symptoms resistant to conservative treatment.

The most established form of neuromodulation for bowel dysfunction, , involves low-dose neural stimulation of the sacral nerve roots via permanently implanted electrodes placed through the sacral foramen at the level of S2 to S4.

This expensive and invasive technique is not suitable for the routine treatment of the subset of constipated patients who fail to benefit from conventional (and sometimes even intensive) treatment. Conventional treatments typically include a variety of strategies beginning with lifestyle advice addressing dietary fiber and fluid intake, followed by the use of laxatives, both osmotic and stimulant.

-- a type of electrotherapy treatment that uses electric currents to stimulate tissue, providing pain relief, reduction of swelling, and many other health benefits -- has long been used to treat conditions such as low back pain and carpal tunnel syndrome.

TES involves placing four sticky electrodes on the stomach and back, with a gentle current passing between them. Although this non-invasive, painless, and economical therapy has been shown to work in children, there has been limited study of the effects on adults with constipation.

In a small pilot study, Judith S. Moore, PhD, RN, of Monash University in Australia, and colleagues showed that TES benefited women with refractory constipation. Their results were published in .

Thirty-three women with constipation that had not improved with standard treatment received either TES (n=17, mean age 45 years, zero spontaneous bowel movements per week) or sham electrical stimulation (n=16, mean age 44 years, zero number of spontaneous bowel movements per week) on the stomach and back for 1 hour each day for 6 weeks.

The women did not know whether they were receiving the real or the sham treatment.

The number of patients with ≥3 spontaneous bowel movements per week served as the primary endpoint. Clinical secondary endpoints included a change in Patient Assessment of Constipation-Symptoms, Patient Assessment of Constipation-Quality of Life, and an overall symptom severity score (measured at baseline, the midpoint of stimulation, the end of treatment, and 3 months after cessation of treatment).

Treatment was successful in 53% (n=9) of the women in the group receiving TES and only 12% (n=2) of the group receiving sham stimulation (P=0.02).

Laxative use was reduced in 66% of the women who received TES compared with 14% who received the sham treatment. Moore and team also noted reductions in Patient Assessment of Constipation-Symptoms (P=0.03) and overall symptom scores (P=0.05) with the active treatment.

Symptom improvements lasted for at least 3 months after the treatment ended, and there were no therapy-related adverse events.

Study limitations included the small sample size and the fact that the study coordinator was not blinded. A spontaneous complete bowel motion would have been a more robust outcome in line with current guidelines, but the pilot study was underpowered to detect a significant difference despite evidence of a trend, the researchers noted. There was also no formal measure of evacuatory dysfunction (i.e., balloon expulsion test), they added.

Source Reference: 2020; DOI: 10.1111/apt.15642

Study Highlights and Explanation of Findings:

About 15% of the general population experience chronic constipation. In this pilot study, TES improved bowel symptoms in chronically constipated women. Compared with one in eight in the control group, more than half of the women in the active therapy group had three or more spontaneous bowel movements per week -- a trend that was maintained 3 months after cessation of treatment.

Other, but not all, measures associated with constipation, including perceived severity of bowel symptoms, were also significantly improved in the TES group, suggesting that the benefits were real, according to Moore's group.

"Further work will be needed to determine optimal delivery duration and frequency, to define mechanisms of action, and to determine predictors of response. Transabdominal interferential electrical stimulation is a promising new tool in the tool box for patients with refractory constipation symptoms," they concluded.

Asked for his perspective, Kyle D. Staller, MD, MPH, director of the Gastrointestinal Motility Laboratory at Massachusetts General Hospital in Boston, who was not involved with the study, said, "This small trial certainly suggests that transabdominal interferential electrical stimulation may be a promising treatment modality for our patients who are dissatisfied with their current laxative regimen. And we know that a sizable number of patients with constipation are not satisfied with currently available therapies."

He said the study benefited from a robust sham treatment and demonstrated a significant treatment effect despite its small sample size. "Additionally, many of these patients were quite constipated without laxatives, having zero spontaneous bowel movements, and so it would seem that this type of treatment could be effective for more severe cases of constipation," Staller told 番茄社区app.

He said that although the results did not reach the rigor of larger constipation trials in which complete, spontaneous bowel movements are the usual primary endpoint, "this is an impressive pilot study that makes a compelling case for larger randomized trials using the traditional endpoints we are used to seeing from trials in chronic idiopathic constipation."

Staller noted that electrical neuromodulation via electric impulses is being widely investigated in other functional gastrointestinal diseases, as evidenced by recent trials for nausea and vomiting and . "How these modalities affect nerves, where they affect them, and whether they have more of an effect on sensory or motor dysfunction are all still open questions," he said.

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