Unexpected motor block after ultrasound-guided lumbar erector Spinae plane block

The successful use of the erector spinae plane block (ESPB) has been reported for post-operative analgesia in numerous operations due to the widespread use of local anesthetic (LA) and the blocking of the dorsal and ventral rami. ESPB has also been effective for easing lumbar back pain caused by lumbar disc herniation through a high-volume LA application to the lumbar area. While high-volume LA administration increases the effectiveness of the block, it can also cause unexpected side effects due to its coverage area. In the literature, only one study has reported on the development of motor weakness following ESPB application, in a case in which the block was performed at the thoracic level. In the present study, a 67-year-old female patient with lower back and leg pain resulting from lumbar disc herniation developed a bilateral motor block following lumbar ESPB. This is the second report of this type of case in the literature.