This procedure is performed to relieve leg pain caused by complex regional pain syndrome, which may develop after an injury to a joint or limb. Usually a series of injection are needed to treat the problem. Patients lie either on their side or stomach on the table equipped with a special x-ray (fluoroscope) unit, and an intravenous line is started to administer medication to relax the patient. A local anesthetic numbs the skin and tissue down to the sympathetic nerves. The physician slides the needle through the anesthetized tract, the contrast solution is injected. Physician uses a fluoroscope to identify the painful areas and confirmed the correct location of the needle tip. Next, anesthetic solution which sometimes mixed with an anti-inflammatory medicine is injected around the sympathetic nerves to block pain signals from reaching the brain. The legs may feel weak or numb for a few hours after the procedure. Then, pain from the leg should improve. More blocks may be repeated about once a week until the pain subsides. Patients who are on blood thinning medications or who have an infection near the injection site should not receive the block.