Perineural Versus Intravenous Dexamethasone for Brachial Plexus Block: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND Perineural (PN) dexamethasone (DEX) administration can prolong the analgesic time of a brachial plexus block. However, its efficacy and safety are controversial due to its off-label use and different routes of administration. OBJECTIVES This meta-analysis aimed to assess the safety and efficacy of PN versus intravenous (IV) dexamethasone. STUDY DESIGN Systematic review and meta-analysis of randomized controlled trials (RCTs). SETTING Relevant studies were found through a comprehensive literature search of PubMed, Web of Science, Ovid, EMBASE, and the Cochrane Library (from the inception until January 2020). METHODS According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this meta-analysis was conducted to identify RCTs comparing PN and IV dexamethasone in brachial plexus block. A randomized effect model was used in the meta-analysis and the subgroup analysis was performed with adrenaline stratification. The quality of evidence and the strength of recommendations were graded by GradePro version 3.6.1. RESULTS Twelve RCTs with a total of 1,345 subjects were included. We found that PN dexamethasone could prolong the duration of analgesia (mean difference [MD]: 131.82 minutes, 95% confidence interval [CI] [38.96, 224.68], I2 = 82%, P = 0.005), motor block (MD: 218.85 minutes, 95% CI [113.65,324.05], I2 = 72%, P < 0.0001) and sensory block (MD: 209.57 minutes, 95% CI [72.64, 346.50], I2 = 87%, P = 0.003) in the main analysis with significant difference. In the absence of epinephrine, there were no significant differences between PN dexamethasone and IV dexamethasone. Except for adverse-effects, no significant differences were observed in secondary outcomes. PN dexamethasone had slightly higher adverse-effects; however, these could be altered if a sensitivity analysis was conducted. LIMITATIONS There was high heterogeneity among included studies. CONCLUSIONS PN dexamethasone can prolong the duration of analgesia, sensory block, and motor block, when compared with IV dexamethasone. In a subgroup analysis without epinephrine, the 2 routes of administration were equivalent to topical anesthesia. There were no differences in secondary outcomes, except for adverse effects, which could be altered if a sensitivity analysis was conducted. Therefore, despite the advantages of PN dexamethasone, caution is needed due to its off-label character. While the results of this study are promising, additional large and well-designed RCTs are needed to validate these initial findings and their implications.