Effects of transcranial direct current stimulation in pain and opioid consumption after spine surgery

Background: Transcranial direct current stimulation (tDCS) has shown promising results in alleviating different types of pain. The present study compares the efficacy of three sessions of anodal tDCS applied over primary motor area (M1) or the left dorsolateral prefrontal cortex (DLPFC) or sham on reducing pain and the total opioid consumption in postoperative spine surgery patients. Materials: Sixty-seven out of 75 eligible patients for postoperative spine surgery were randomly allocated into one of the three experimental groups. Group A received anodal tDCS applied over M1 cortex, group B over left DLPF cortex (2 mA, 20min) and group C received sham tDCS, all for 3 consecutive postoperative days. Patients were evaluated using a visual analogue scale (VAS) and adynamic visual analogue scale (DVAS) at baseline, and on each of the treatment days. The total morphine consumption over the 3 postoperative days was assessed. Results: Two-way repeated measures ANOVA showed no statistically significant difference in resting VAS between the three groups. However, there was significant pain improvement (P <0.001) in DVAS in both active groups (group A and B) compared to the sham group (group C) in the postoperative period, with no significant difference between the active groups. Morphine consumption was significantly reduced in both active groups compared with the sham group, but there was no difference in consumption between the active groups. Conclusion: There was a significant postoperative reduction in morphine consumption and DVAS scores after three sessions of active tDCS. Significance: tDCS is a promising tool for alleviating pain in the field of postoperative spine surgery.