Human lumbar sympathetic blockade: An anatomical study to address potential block failure

Abstract

The lumbar sympathetic block is often used to treat complex regional pain syndrome, but it seems to have a high failure rate. This study seeks anatomical explanations for this apparent failure in order to refine our block procedure. Two simulated sympathetic trunk blocks were carried out on four fresh, cryopreserved unembalmed human cadavers under fluoroscopic control at the L2 vertebral body level, followed by two further simulated blocks at the L4 vertebral body level on the other side. Dye was injected, and the areas were dissected following a specific protocol. We then describe the anatomy and the spread of the dye compared to the spread of the contrast medium on fluoroscopy. The ganglia were differently located at different vertebral levels, and differed among the cadavers. Following this anatomical clarification, we now prefer to perform lumbar sympathetic blocks at the fourth lumbar vertebra level, using an extraforaminal approach at the caudal end of the vertebra, avoiding the anterolateral margin of the vertebral body at the midpoint.

Clinical results of lumbar sympathetic blocks in lower limb complex regional pain syndrome using infrared thermography as a support tool

“…3,12 In clinical practice, lumbar sympathetic blocks (LSBs) are performed under fluoroscopic control, 9 targeting the anterolateral part of the lumbar vertebrae, but with no clear target regarding the specific point where the ganglion is located. 13 Moreover, fluoroscopic monitoring has limited accuracy as it is based only on a two-dimensional image. Implementing intraoperative monitoring to check in realtime whether the anatomical target has been reached may improve the accuracy of LSBs.…”