Comparison of Analgesic Effects of Different Regional Blocks in Video-assisted Thoracic and Breast Surgeries: A Network Meta-analysis and Systematic Review

Background: Postoperative pain management in breast surgery and video-assisted thoracic surgeries (VATS) remains challenging. Oral or intravenous infusion of opioids were early treatments, but they can result in gastrointestinal reactions, respiratory inhibition, and other adverse reactions. In recent years, various regional block techniques have been employed for postoperative analgesia of these surgeries. However, a pair-wise meta-analysis cannot comprehensively rank and evaluate the analgesic effects and adverse events of various regional blocks. Objective: The purpose of this network meta-analysis (NMA) was to compare the analgesic effects and adverse events of different regional block techniques after breast surgery and VATS. Study Design: NMA of randomized controlled trials (RCTs) for comparing multiple regional block techniques in breast surgery and VATS. Methods: Pubmed, Embase, and Cochrane databases were searched systematically for RCTs comparing analgesic effects and adverse events after breast surgery and VATS. After critical appraisal, a random-effects NMA was mainly used to compare all the regional blocks' analgesic effects and adverse events. The Population, Interventions, Comparators, Outcomes, and Study design (PICOS) framework was used to build the search strategies and present the results according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. The primary endpoint was opioid consumption within 24 hours after the operation; secondary endpoints included dynamic and static pain scores and the incidence of nausea and vomiting. This study is registered in the Prospective Register of Systematic Reviews (PROSPERO) with a PROSPERO number of CRD42021283907. Results: A total of 21 clinical trials, including 1,284 patients and 6 different regional block techniques (paravertebral block pectoral nerve block serratus anterior plane block [SAPB], intercostal nerve block [ICNB], erector spinal plane block and thoracic epidural anesthesia), were included and analyzed. There was no significant difference between the consistent and the inconsistent models. Based on limited evidence, SAPB may be the most effective regional block technique for relieving postoperative pain, while ICNB had the lowest probability of nausea and vomiting. There was no significant difference in the pair-wise comparisons. In this study, we found no obvious publication bias. Limitations: Limitations include: morphine milligram equivalents were not used to calculate opioid consumption; the scales used in the studies were different; the number of studies and total sample size included was limited; non-English literature and gray literature were not included; more databases were not searched. Conclusions: After a comprehensive evaluation of postoperative analgesic effects and adverse events based on the NMA, we hypothesize that SAPB and ICNB have distinct advantages in postoperative analgesia and reduce the incidence of nausea and vomiting, respectively. However, conclusions drawn from more RCTs may be more convincing.