Unanticipated Motor Weakness with Ultrasound-Guided Transversalis Fascia Plane Block.

The transversalis fascia plane block is a relatively new truncal block that targets the iliohypogastric and ilioinguinal nerves. It is gaining wider usage for its reliability to block these nerves as compared with the transversus abdominis plane block. The case presented here appears to be the first time that motor weakness has resulted from this block technique. It is suspected that central and proximal spread of local anesthetic toward the psoas muscle may have resulted in a partial lumbar plexus block.