The sympathetic nerves run on the front surface of the spinal column (not in the spinal canal with the nerves from your central nervous system). The sympathetic nerves are part of the autonomic nervous system, which basically controls functions like blood flow to the extremities, sweating, heart rate, digestion, blood pressure, goose bumps and many other functions. In other words, the autonomic nervous system is responsible for controlling things you do not think about or have direct control over. However, there is a connection between the central and autonomic nervous systems. Sometimes arm or leg pain is caused by a malfunction of the autonomic system secondary to an injury.
How does a Sympathetic Nerve Block Work?
A sympathetic nerve block involves injecting medicine around the sympathetic nerves in the lumbar or cervical area. By doing this, the system is temporarily blocked in hopes of reducing or eliminating your pain. If the initial block is successful, then an additional sympathetic nerve block is generally repeated in 7 – 10 days and repeated again until your pain diminishes.
An IV will be started so that there is intravenous access for your safety and relaxation medication can be given. You will be placed on the X-ray table on your back for a cervical (Stellate Ganglion) block and on your stomach for a lumbar block. The area of skin on your neck low back will be cleaned using sterile solution.
Next, the physician will numb a small area of skin with numbing medicine. This medicine stings for several seconds. After the numbing medicine has been given time to be effective, your doctor will direct a very small needle, using X-ray guidance, to the area of the sympathetic nerves. A small amount of contrast (dye) is then injected to ensure proper needle position. Then, typically a mixture of anesthetic medicine and anti-inflammatory steroid will be injected as the sympathetic nerve block.