Determination of Spread of Injectate After Ultrasound-guided Interscalene and Supraclavicular Brachial Plexus Block: A Fresh Cadaveric Study

Abstract Objective The aim of this anatomical study was to establish the likely spread of local anesthetics in vivo and the segmental nerve involvement resulting from ultrasound-guided interscalene brachial plexus blocks and supraclavicular brachial plexus blocks. Materials and Methods We performed ultrasound-guided injections of different alinine dyes into the right brachial plexus at the interscalene and supraclavicular levels in seven fresh human cadavers. We then dissected the cadavers to determine the extent of dye spread and the nerve that was dyed. Results The cadavers provided excellent sonographic images during nerve blocks. After excluding one pilot specimen, six right brachial plexus blocks were successfully performed and dissected. The extent of dye spread and nerve involvement were different in the interscalene brachial plexus blocks and supraclavicular brachial plexus blocks. The phrenic nerve with dye was identified in the interscalene brachial plexus block. Conclusion This study showed that the extent of dye spread and nerve involvement differs in interscalene and supraclavicular brachial plexus blocks. Phrenic nerve involvement in the interscalene block was confirmed through dissection. Fresh human cadavers, by providing excellent sono-graphic images, are potential learning and practice models in ultrasound-guided brachial plexus blocks.