Efficacy and safety of extrafascial injection versus intrafascial injection for interscalene brachial plexus block: a systematic review and meta-analysis.

ABSTRACT

INTRODUCTION: This systematic review and meta-analysis aimed to assess the efficacy and safety of interscalene brachial plexus block (ISB) techniques in upper limb and shoulder surgeries. EVIDENCE ACQUISITION We conducted a comprehensive search of PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Embase, Medline, and Scopus databases up to May 14th, 2023. We employed a search strategy involving keywords such as "brachial plexus block," "interscalene brachial plexus block," "ISB," "extrafascial," and "intrafascial," without applying search restrictions or filters. Eligible studies consisted of randomised controlled trials (RCTs) that compared extrafascial and intrafascial ISB techniques in adult patients undergoing upper limb and shoulder surgeries. EVIDENCE SYNTHESIS: Our analysis included six RCTs encompassing 485 participants. Extrafascial injection demonstrated superiority over intrafascial injection in reducing the incidence of hemidiaphragmatic paresis (RR 0.33, 95% CI 0.124 to 0.47, P<0.00001) and preserving respiratory function (MS 0.31, 95% CI 0.1 to 0. 52, P=0.003 FEV1 in liters). Additionally, extrafascial ISB exhibited a lower risk of block-related complications (RR 0.35, 95% CI 0.25 to 0.50, P<0.00001). However, the intrafascial technique offered a faster sensory and motor block onset. The duration of sensory block did not significantly differ. The incidence of Horner syndrome showed no statistically significant difference. CONCLUSIONS: Our findings favor extrafascial ISB techniques because they reduce hemidiaphragmatic paresis, preserve respiratory function, and lower block-related complications. However, further research is necessary to establish their safety and efficacy in specific patient populations.