Lumbar Sympathetic Block

A plexus is a group of nerves. A LSB is the injection of local anesthetic (like Novocain) in your low back (lumbar) region around the lumbar sympathetic plexus, a group of nerves that control blood flow in your legs, as well as pain sensations. A LSB may be performed if your leg pain is thought to be sympathetically mediated, neuropathic, or ischemic from blocked arteries. A LSB is both diagnostic as well as therapeutic, meaning that in addition to determining the cause of your pain, the block may treat the pain problem as well. Sympathetic pain results from the inappropriate activation of sympathetic nerves. This can result from any type of injury, large or very small, such as a paper cut. For whatever reason, sometimes these nerves are activated and result in a chronic pain syndrome. This syndrome is referred to either as Complex Regional Pain Syndrome (CRPS type I and II). These used be called RSD (reflex sympathetic dystrophy) and causalgia. Often the skin becomes very sensitive, often changes color and temperature, and is associated with severe spontaneous pain at times. If left untreated, it can become somewhat permanent. Medications may not be effective. The appropriate treatment involves temporarily blocking these sympathetic nerves with local anesthetics either once, or multiple times if needed. It is not known why temporarily blocking these nerves re-sets the nerves back into their normal state, thus treating the pain syndrome. Neuropathic pain is similar to sympathetic pain, but without the skin color and temperature changes. It also can respond to sympathetic blocks. Ischemic pain results when muscle and skin tissue are starved of blood flow, meaning oxygen. Blocking the sympathetic nerves can increase blood flow to the tissue.

An IV will first be placed in your arm. You will be placed prone (face down) on the fluoroscopy table. Your low back will be cleansed with an antiseptic and then numbed. The doctor will use X-ray to help guide the needle and then will inject a very small amount of dye to confirm correct placement of the needle before injecting the local anesthetic. The procedure will take about 30 minutes. A Band-Aid will be applied to the injection site and you will be taken to the recovery area. A nurse will review your discharge instructions with you before going home.

Tip:

For cases where the injection is effective but the duration of action is not long enough, radiofrequency treatment of the sympathetic plexus can provide longer lasting relief.