Chapter 16 - Lumbar Sympathetic Block

Abstract

Sympathetic nerve blocks are used to help with the diagnosis and treatment of sympathetically maintained pain. The lumbar sympathetic chain typically overlies the anterolateral aspect of the first through fourth lumbar vertebrae. The axons of the lumbar sympathetic preganglionic neurons exit the spinal cord through the ventral roots of the first four lumbar spinal nerves and send fibers through the white rami communicantes to the corresponding lumbar sympathetic ganglia. Postganglionic fibers then exit the chain to join a vascular plexus or the spinal nerves via the gray rami communicantes. The largest portion of lumbar sympathetic ganglia is located in the area of the second and third lumbar vertebrae. Therefore, a single-level block along the lower third of L2 or the upper third of L3 is usually sufficient as long as there is adequate medication spread. This chapter describes an injection at the L3 level.