Performed to determine if there is damage to the sympathetic nerve chain. This is a network of nerves extending the length of the spine. These nerves control some of the involuntary functions of the body and sometimes carry painful impulses.

How it's performed
Unlike other blocks, sympathetic nerve blocks involve injecting anesthetic into different nerves. These may include stellate ganglion, celiac plexis, hypogastric plexis, ganglion of impar and lumbar sympathetic nerve blocks. The procedure lasts 10-20 minutes.