Feasibility, safety, and effectiveness of transcranial direct current stimulation for decreasing post-ERCP pain: a randomized, sham-controlled, pilot study

Background: Emerging evidence shows that transcranial direct current stimulation (tDCS), a minimally invasive brain stimulation technique, has analgesic effects in chronic pain patients and in healthy volunteers with experimental pain. No studies have examined the analgesic effects of tDCS immediately after surgical/endoscopic procedures. Endoscopy investigating abdominal pain, especially ERCP, can cause significant postprocedural pain. Objective: To test the feasibility, efficacy, and safety of tDCS on post-ERCP pain and analgesia use. Design: Randomized, sham-controlled, pilot study. Setting: Tertiary-care medical center. Patients: This study involved 21 patients who were hospitalized overnight for ERCP for unexplained right upper quadrant pain. Intervention: Twenty minutes of real 2.0 mA tDCS or sham (anode over left prefrontal cortex; cathode over gut-representation of right sensory cortex) immediately after ERCP. Main Outcome Measurements: Pain (visual analogue scale, McGill pain questionnaire, brief pain inventory), patient-controlled analgesia use, adverse events. Results: Real tDCS was associated with 22% less total hydromorphone use, versus sham. The slope of the cumulative patient-controlled analgesia usage curve was significantly steeper in the sham tDCS group (F [2,13] = 15.96; P = .0003). Real tDCS patients reported significantly less pain interference with sleep (t [17] = 3.70; P = .002) and less throbbing pain (t [16] = 2.37; P = .03). Visual analogue scale pain and mood scores (4 hours post-ERCP) suggested a nonsignificant advantage for real tDCS, despite less hydromorphone use. Side effects of tDCS were limited to mild, self-limited tingling, itching, and stinging under electrodes. Limitations: Small sample size, variability in chronic pain, and chronic opioid use. Conclusion: In this pilot study, tDCS appears to be safe, has minimal side effects, and may reduce postprocedural analgesia requirements and subjective pain ratings. Future studies appear warranted. (Gastrointest Endosc 2011;73:1158-64.)