Sympathetic Nerve Blocks

What are sympathetic nerve blocks and what are they used for?

Sympathetic nerve blocks are injections that target the bundles of sympathetic nerves. These sympathetic nerves may be involved in transmitting the pain sensation from different parts of the body. By performing a sympathetic nerve block, this pain transmission can be interrupted, giving good pain relief in some cases. Depending on where these blocks are performed, the sympathetic nerve blocks are given different names. A stellate ganglion block can be useful in some cases of head, neck, upper limb and upper chest pain; a splanchnic nerve block, celiac plexus and superior hypogastric block targets pain from various organs in the abdomen or pelvis, and and lumbar sympathetic nerve block treats pain in the legs.

What happens doing the sympathetic nerve block procedure?

During the procedure, you will be lying on your front or back depending on where the target is. After some sedation, your skin will be cleansed. Local anaesthetic is given, after which thin needle is placed under ultrasound or X-ray guidance to the target site. A solution of local anaesthetic and steroid is then given. You will then be sent to the recovery area to rest for about an hour after which you can go home. The procedure should take around half an hour. In some cases of cancer pain or intractable pain that has responded to the injection of local anaesthetic and steroids, a neurolytic block can be performed with alcohol or phenol, aiming to destroy the pain fibres to provide lasting pain relief.

What are the possible side effects and complications?

The possible side effects from a sympathetic nerve block can include bleeding, infection and nerve damage. Depending on where the target it, the specific side effects may differ. For example, a stellate ganglion block may temporarily result in hoarseness of voice, difficulty drinking and swallowing, a lumbar or superior hypogastric block can cause sexual dysfunction in males. Blocks that target pain in the abdomen and pelvis may cause diarrhea.

How long can the block last?

In general, the block can last months to years. If the pain recurs early and the duration is not satisfactory, an alcohol or phenol neurolytic block aiming to destroy the sympathetic nerves is done to improve quality of pain control and duration of pain relief.