What is a sympathetic nerve block?

A sympathetic nerve block is an injection of medicine around nerves in your neck or back. This nerve block is used for problems such as chronic regional pain syndrome and pain from some types of cancer.

Sympathetic nerves spread out from your spine. They control some of the body functions you have no control over, like blood flow and digestion. They also carry pain signals. When this system isn't working right, you can have long-term (chronic) pain.

The nerves come together in groups called ganglions throughout your body. This is where the nerve block is done. Your doctor will decide which group of nerves needs this treatment.

The nerve block contains anesthetic, which usually numbs the nerves. It may also contain a steroid, which may reduce swelling and pain. Steroids take a few days, and they don't always work.

How is a sympathetic nerve block done?

First the doctor will use a tiny needle to numb the skin. Then the doctor puts the nerve block needle into the numbed area. Your doctor may use X-rays or ultrasound to help guide the needle. You may feel some pressure. But you should not feel pain.

What can you expect after a sympathetic nerve block?

You will probably go home about an hour after the injection.

Sympathetic nerve blocks don't always work. If it does work, you may feel less pain right away. Sometimes the pain comes back after the anesthetic wears off.

If your nerve block included a steroid, it may take a few days to relieve the pain.

You may want to do less than normal for a few days. Or you may be able to return to your daily routine. Pain relief can last for several days to a few months or longer. The block may need to be repeated.