Effect of transcranial direct current stimulation on pain anxiety during burn wound care.
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  = 3.70; P = .002) and less throbbing pain (t  = 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.