A Lumbar Sympathetic Block is an injection of local anesthetic into the sympathetic nerves. The sympathetic portion of the nervous system is responsible for fight of flight response, maintaining balance or homeostasis in the body and can carry pain messages. The lumbar sympathetic nerves carry these sympathetic nerve messages form the lower extremities to the brain. A Lumbar Sympathetic Block is often administered to relieve many conditions such as Reflex Sympathetic Dystrophy, Shingles, leg swelling and leg pain. It is an out patient procedure that does not require anesthesia. Most people can return to work the next day. Many people experience immediate but temporary relief. Multiple injections may be prescribed as each one tends to last longer and longer.