Papers of the Week

The transversalis fascia (TF) encases the quadratus lumborum and psoas major (PM) muscles, respectively, after they split caudalward approximately at the level of the iliac crest. The branches of the lumbar plexus variably exit medially and laterally from the TF-encased PM muscle. We hypothesized that the local anesthetic (LA) injections around the anterolateral edge of PM at the supra-iliac level and into the retro-psoas compartment at the L5/S1 level, which termed as the circum-psoas blocks, could block the lumbar plexus branches. Therefore, here we evaluated the sensory loss caused by the circum-psoas blocks.