Sacral nerve modulation for irritable bowel syndrome: A randomized, double-blinded, placebo-controlled crossover study.

Abstract

Irritable bowel syndrome (IBS) is among the most common gastrointestinal disorders, and a substantial proportion of patients have an insufficient response to treatment. In a single-blinded study, sacral nerve modulation (SNM) significantly reduced symptoms of IBS. The aim of the present double-blinded, randomized, placebo-controlled study was to evaluate the effect of SNM for IBS. We included patients with diarrhea-predominant or mixed IBS and a minimum baseline IBS-specific symptom score of 40 points (Gastrointestinal Symptom Rating Scale-IBS version). Patients underwent a 6-week period of SNM. In the first 4weeks, the patients were randomized 1:1 to have the neurostimulator set subsensory or OFF for 2weeks and then the opposite for another 2weeks. Patients and investigators were blinded to settings. In the remaining 2weeks, the stimulation was set suprasensory. IBS-specific symptoms and quality of life were assessed with validated questionnaires and bowel diaries. Twenty-one patients were randomized and eligible for analysis. The IBS-specific symptom score was reduced with borderline significance during stimulation (subsensory-OFF median change -1 (-26, 9), OFF-subsensory median change 8 (-11, 36); P=0.0572). Pain was significantly reduced during stimulation (subsensory-OFF median change -1.5 (-4, 1), OFF-subsensory median change 1 (-4, 3); P=0.0188), along with the number of daily bowel movements (subsensory-OFF median change 0 (-1.8, 0.2), OFF-subsensory median change 0.2 (-0.5, 1.1); P=0.0373). The median placebo effect was 14% (0, 55). Sacral nerve modulation for IBS seems promising but should be considered experimental until larger multicenter studies have been performed.