Sacral nerve stimulation reduced irritable bowel symptoms



Permanent sacral nerve stimulation looked promising in a prospective, randomized controlled study to reduce symptoms in a select group of 21 adults with diarrhea-predominant or mixed irritable bowel syndrome.

In this crossover trial, all patients had sacral nerve stimulators implanted. One group had the stimulator turned on for 1 month and off the next month, while the other group had the opposite – the stimulator was off and then on during those same time periods. Active stimulation improved symptom scores as measured by the Gastrointestinal Symptom Rating Scale – Irritable Bowel Syndrome (GSRS-IBS).

The median change in symptom scores between months 1 and 2 differed significantly between the two groups. In the group that had the stimulator on and then off, symptom scores increased by a median of 12 points. In the group that had the stimulator off and then on, scores decreased by a median of 18 points, Janne L. Fassov, Ph.D., and associates reported.

One year later, with sacral nerve stimulation continuing and data available from 19 patients, the median GSRS-IBS score of 25 was significantly lower than the median symptom score of 62 at baseline, reported Dr. Fassov of Aarhus (Denmark) University Hospital.

The Annals of Surgery published the findings online ahead of print (2014 Feb. 6 [doi:10.1097/SLA.000000000000559]).

The investigators recruited 43 patients from their tertiary care institution who had failed standard treatments for diarrhea-predominant or mixed irritable bowel syndrome. After undergoing a percutaneous nerve evaluation under general anesthesia, they underwent 3 weeks of stimulation using a test electrode connected to an external neurostimulator. Thirty-one patients who had at least a 30% reduction in GSRS-IBS symptom scores during the 3-week test period were offered permanent implantation of the neurostimulator. Patients worked with a nurse specialist for 1-20 months after implantation to individually optimize the stimulator settings for best symptom control before being randomized in the current study.

Two patients who became pregnant and three who withdrew consent did not get stimulators. Five of 26 patients with permanent implantation were excluded from the results, two because of gastric bypass procedures before the crossover month, one who was mentally unstable, and two who refused to have the stimulator turned off because of its excellent effects.

Although patients and investigators were not told when the stimulators were on or off, patients usually could sense when they were on, so the study was not truly blinded.

One of the 21 remaining patients withdrew from the study before finishing it after needing morphine to relieve abdominal pain during the month that the neurostimulator was off.

In the 20 patients who completed the study, quality of life scores on the Irritable Bowel Syndrome Impact Scale (IBS-IS) improved during the month with stimulation. When stimulation went from on to off, IBS-IS scores increased by a median of 16 points. When stimulation went from off to on, IBS-IS scores decreased by a median of 42 points. The difference in median changes between the two groups was statistically significant.

Scores improved significantly with stimulation in all five domains of the symptom scale (pain, bloating, constipation, diarrhea, and satiety) and in all five domains of the quality of life scale (fatigue, daily impaired activities, sleep, emotional distress, and eating habits).

Ten device-related adverse events in seven patients included elective revision of the lead for suspected migration in two patients, persistent postoperative pain at the implantation site requiring relocation of the pacemaker in three patients, recurrent cystitis in one patient that resolved with triple voiding, and spontaneously resolving postoperative pain at the implantation site in four patients.

Sacral nerve stimulation is a well-established, cost-effective treatment for fecal incontinence, and the effects of stimulation for inflammatory bowel disease in this study were similar to those that have been reported for fecal incontinence, the investigators noted. Because minor complications are common with sacral nerve stimulation, this treatment should be reserved for patients with inflammatory bowel disease who do not respond to pharmacotherapy, they suggested.

Medtronic provided its neurostimulators for the study free of charge. Some of Dr. Fassov’s associates in the study have been speakers and/or advisers for Medtronic. The Danish Council for Strategic Research funded the study.

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