A block that is performed to determine if there is damage to or alteration in the sympathetic nerve chain and if it is the source of pain. This is a diagnostic test primarily, but it may provide relief far in excess of the duration of the anesthetic. A local skin anesthetic is given in the lumbar area of the back. A needle is then inserted into the back under fluoroscopy next to the vertebral body. The block may be performed on both sides of the spine. An anesthetic medication will be injected into the area.