Nerve Blocks Nerve blocks are injections of local anesthesia around the sympathetic nerves in the neck or lower back. The sympathetic nerves are present on the front side of the spinal column. This chain of nerves is part of the autonomic nervous system and controls such bodily functions as sweating, heart rate, digestion, and blood pressure. In some cases following an injury, the sympathetic nervous system becomes activated. This can result in the condition known as Complex Regional Pain Syndrome (CRPS), formerly called Reflex Sympathetic Dystrophy (RSD). Symptoms of CRPS include severe burning pain, swelling, and skin color changes in an upper or lower extremity following an injury. The nerve block procedure blocks can be used at the Stellate Ganglion, a grouping of sympathetic nerves in the neck. This type of block is helpful for pain in the arm, shoulder, or facial area. A Lumbar Sympathetic Block is helpful for back, leg, or foot pain. These nerve blocks not only help to ease the painful symptoms of CRPS, they also confirm the diagnosis. A series of nerve block injections may be required depending upon the severity of the condition.