Small intestinal motility in IBS patients unaffected by sacral nerve stimulation
Sacral nerve stimulation therapy had no detectable effect on gastric emptying or small intestinal motility in patients with diarrhea-predominant or mixed irritable bowel syndrome, according to recent study data.
Researchers from Aarhus University Hospital in Denmark performed a controlled crossover study of 20 patients (median age, 31 years; 15 women) with severe diarrhea-predominant or mixed irritable bowel syndrome (IBS) by using sacral nerve stimulation (SNS) to assess its efficacy in IBS-related dysmotility.
During the 2-month study period, participants were randomly grouped to have their neurostimulator turned on or off for the first 4 weeks and then to the opposite setting for the next 4 weeks. Gastrointestinal transit patterns were assessed based on changes in velocity of the magnetic pill measured by the Motility Tracking System-1 (Motilis, Lausanne, Switzerland) at the end of each period. Patients and investigators were masked to the neurotransmitter’s setting.
The magnetic pill’s median velocity through the small intestine in the initial fasting period was similar compared with periods with and without SNS (On/Off Group: median change 0 m/hour; range, –1.07 to 0.63; Off/On Group: median change 0.27 m/hour; range, –0.59 to 1.12; P=.25). Likewise, similar median velocity was measured in the postprandial period compared with periods with and without SNS (On/Off Group: median change –0.13 m/hour; range, –0.46 to 0.23; Off/On Group: median change 0.015 m/hour; range, –0.48 to 0.59; P=.14). These measurements were true in the diarrhea-predominant and mixed IBS subgroups. There also was no difference in gastric emptying with or without SNS (On/Off Group: median change 3.5 minutes; range, –304 to 79; Off/On Group: median change –33 minutes; range, –128 to 70; P>.09).
“Even though SNS reduces the frequency of defecation, episodes of urgency, and time spent on toilet, this occurs without major changes in small intestinal transit patterns,” the researchers concluded. “We speculate that the effects of SNS in IBS may be caused by modulation of afferent nerve fibers causing altered colorectal sensory perception.”
Disclosure: See the study for a full list of relevant financial disclosures.