Nerve blocks

• Medial branch block: numbs the tiny nerves to the facet joints, the small joints at the back of the spine. Used for arthritis-type neck or back pain that is worse with twisting or leaning back. Two good responses usually lead to radiofrequency ablation, which can give 6 to 12 months or more of relief.
• Genicular nerve block: numbs the nerves around the knee. It is the test before genicular nerve ablation.
• Selective nerve root block: targets one spinal nerve as it exits the spine, for sciatica or arm pain. It is closely related to an epidural steroid injection.
• Stellate ganglion block: targets a bundle of nerves in the front of the neck that controls blood flow and sweating in the arm and face. Used for complex regional pain syndrome (CRPS) of the arm and some other conditions.
• Lumbar sympathetic block: the same idea in the lower back, for CRPS or poor circulation pain in the leg.
• Celiac plexus block: targets a web of nerves deep in the upper belly that carries pain from the pancreas, liver, stomach and nearby organs. Most often used for pancreatic cancer pain.
• Superior hypogastric and ganglion impar blocks: target nerves in front of the lower spine and tailbone, for pelvic or tailbone pain, often from cancer.
• Other peripheral blocks: such as occipital nerve blocks for headaches at the back of the head and intercostal blocks for rib pain.

• Tell us about blood thinners. Some blocks near the surface are safe while you keep taking them, but deeper blocks near the spine or in the belly usually require a pause. See blood thinners.
• If you have diabetes, check your blood sugar more often for a few days after a steroid block, because steroids can raise it.
• If you will have sedation, do not eat or drink for about 6 to 8 hours beforehand, and arrange a ride home.
• For a diagnostic block, come with your usual pain. Avoid taking extra pain medicine that morning unless we tell you to, so the test is accurate.
• Bring a simple pain diary or use your phone to record your pain every hour or two after the block.

Expected short-term effects of specific blocks

• Stellate ganglion block: a droopy eyelid, small pupil, red eye, stuffy nose or hoarse voice on the same side for a few hours. This is expected and shows the block worked. Do not eat or drink until swallowing feels normal.
• Lumbar sympathetic block: the leg may feel warm.
• Celiac plexus block: loose stools and feeling light-headed when standing up are common for a day or two. Stand up slowly and drink plenty of fluids.

Possible risks

• Soreness or bruising at the injection site for a few days.
• Temporary numbness or weakness in an arm or leg, usually gone within hours.
• Steroid side effects: flushing, trouble sleeping, higher blood sugar for a few days.
• Infection or bleeding, both uncommon.
• Allergic reaction to medicines or contrast dye, rare.
• Spinal headache if the needle punctures the covering of the spinal fluid, uncommon.
• For deep blocks: rare injury to nearby blood vessels, organs or nerves, including very rare paralysis after celiac plexus neurolysis, and a small risk of collapsed lung with some chest wall and neck blocks.