Perineural block is superior to intravenous dexamethasone block during a single injection of scalenus muscle in the shoulder under arthroscopy：a meta- analysis

Purpose: Both perineural and intravenous dexamethasone prolongs the efficacy of a single interscalene brachial plexus block (ISB). But there is currently debate about the best route of administration. The purpose of this meta-analysis was to compare the efficacy and safety of perineural injection of dexamethasone versus intravenous injection of dexamethasone in the treatment of ISB during arthroscopic shoulder surgery. Methods: Relevant studies published before May 05, 2021 were retrieved from PubMed, Embase, and Web of Science databases according to the preferred reporting items of the Systematic Evaluation and Meta-analysis (PRISMA) guidelines. The primary outcomes were duration of analgesia, sensory and motor block. The secondary outcomes included postoperative pain, opioid consumption and incidence of adverse events. We performed a meta-analysis to find significant differences between the two modalities. Results: Seven studies were identified (846 patients). Perineural injection of dexamethasone can significantly prolong the analgesic time (WMD: 1.699 hours; 95% CI: 0.0014, 3.384; P: 0.048) and reduced postoperative pain at 12 hours (WMD: -0.652; 95% CI: -1.129, -0.176; P: 0.007). There was no significant difference between the two groups regarding the duration of sensory and motor block, postoperative pain and opioid consumption at 24 hours, and incidence of adverse events (dyspnea, sleep disturbance, and postoperative glucose change). Conclusions: The current evidence demonstrated the superior effect of dexamethasone is used around the nerve for prolonged analgesia and reducing acute postoperative pain.