Efficacy and Safety of Perioperative Transcranial Electrical Stimulation for Postoperative Pain and Related Outcomes: A Systematic Review and Meta‐Analysis With Trial Sequential and Subgroup Analyses
Zehao Liu, Yixin Zhang, Yangyang Li, Dezhou Jiang, Funing Liu, Chunmei Wu, Xiaolan Li, Suying Li, Wenjie Mao, Qing ZhongObjectives
Transcranial electrical stimulation (tES) is a neuromodulation technique that can serve as an adjuvant tool during the perioperative period. With emerging randomized controlled trials (RCTs) supporting its efficacy across various surgical procedures, synthesis of current evidence and evaluation of its potential for postoperative analgesia in elective‐surgery patients and related outcomes are urgently needed.
Materials and Methods
We initially searched PubMed, the Cochrane Library, MEDLINE, and Embase for RCTs investigating perioperative tES in patients undergoing elective surgery. The search period covered from the inception of each database to September 2025, and an updated search for newly published studies was conducted in September 2026. We analyzed the outcomes, including postoperative pain scores, opioid consumption, quality of recovery, incidence of postoperative delirium, and adverse events. The Cochrane Risk of Bias 2 (RoB 2) tool was used to evaluate the risk of bias in included studies. Sensitivity and publication bias analyses were performed. Exploratory subgroup analysis and meta‐regression were performed to identify sources of heterogeneity. We also analyzed outlier studies. Trial sequential analysis (TSA) was further performed to evaluate the robustness of evidence. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to assess the certainty of the evidence.
Results
A total of 21 RCTs with 2186 participants were included in this meta‐analysis. Compared with the control group, the tES group showed lower pain scores on postoperative day 1 (standardized mean difference [SMD] = −0.57, 95% CI: −0.84 to −0.30, p < 0.01), reduced total opioid consumption (SMD = −0.47, 95% CI: −0.74 to −0.20, p < 0.01), a lower incidence of postoperative delirium (risk ratio [RR] = 0.45, 95% CI: 0.25 to 0.79, p < 0.01), and a lower incidence of postoperative nausea or vomiting (RR = 0.84, 95% CI: 0.75 to 0.95, p < 0.01). No significant differences were observed between the two groups in postoperative day 1 quality of recovery (SMD = 0.44, 95% CI: −0.18 to 1.05, p = 0.16) and dizziness or headache (RR = 1.01, 95% CI: 0.70 to 1.47, p = 0.94). In addition, tES might increase the risk of mild and transient stimulation site discomfort (RR = 3.10, 95% CI: 1.96 to 4.90, p < 0.01). The initial timing and number of stimulation sessions were potential sources of heterogeneity for postoperative day 1 pain scores, while initial stimulation timing, stimulation modality, and target sites were associated with heterogeneity in total opioid consumption. TSA results indicated that the current sample size was sufficient to confirm the beneficial effects of tES on postoperative day 1 pain, total opioid consumption, and postoperative delirium. The certainty of evidence ranged from very low to moderate.
Conclusions
Current evidence suggests that tES, as an adjuvant perioperative intervention, may alleviate postoperative pain, reduce opioid consumption, and decrease the incidence of postoperative delirium. However, the effect of tES on postoperative quality of recovery remains unclear. Considering the limited overall quality of current evidence, whether tES can serve as a universal adjuvant analgesic method for patients undergoing elective surgery still needs further clarification.