Effects of erector spinae plane block on postoperative pain and side-effects in adult patients underwent surgery: A systematic review and meta-analysis of randomized controlled trials

Background: Recently, the effects of erector spinae plane block on postoperative pain have become increasingly controversial. This meta-analysis compared the effects of ESP block versus placebo on postoperative analgesia and side effects to determine whether the new technique is a reliable alternative for pain management. Methods: PubMed, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), and Wanfang Database were searched for clinical studies investigating the analgesic effect of ESP block versus placebo. The primary outcomes included the visual analogue scale (VAS) at rest and during movement, as well as the postoperative morphine consumption in 24 h, and the secondary outcome was the rate of postoperative nausea and vomiting (PONV). The choice of using the fixed or random-effects model depended on whether the heterogeneity tested by I-2 statistic was more than 50%. Seeking sources of heterogeneity and exploring the effect of clinical details on the final result were performed by subgroup analysis. Additionally, the test for stability of the pooled result was realized by sensitivity analysis. Finally, we evaluated the quality of the evidence for the outcomes. STATA 13.0 software was selected as the main analysis software in the meta-analysis. Results: Eighteen randomized controlled trials (RCTs) comprising 1041 patients were reviewed. This metaanalysis showed that ESP block could significantly reduce patients' pain scores at 1 h, 6 h, 12 h, and 24 h after surgery at rest or during movement; 24-h postoperative morphine consumption; and the incidence of PONV. Conclusions: ESP block as a novel technique exhibited superior postoperative analgesic effects, reducing the postoperative complications in spinal, thoracic, and abdominal surgeries during the early postoperative period. However, as a new nerve block technique, numerous large-sized RCTs are needed for further research.