A nerve block relieves pain by interrupting how pain signals are sent to your brain. It is done by injecting a substance, such as alcohol or phenol, into or around a nerve or into the spine.
Nerve blocks may be used for several purposes, such as:
- To determine the source of pain.
- To treat painful conditions.
- To predict how pain will respond to long-term treatments.
- For short-term pain relief after some surgeries and other procedures.
- For anesthesia during some smaller procedures, such as finger surgery.
Nerve blocks are used to treat chronic pain when drugs or other treatments do not control pain or cause bad side effects. A test block is usually performed with local anesthetic. If you achieve good pain relief from the local anesthetic, your doctor may inject a nerve block, such as alcohol or phenol.
What To Expect After Treatment
Nerve blocks numb the nerves touched by the drugs. This relieves pain by interrupting the pain signal sent by the nerves to your brain. Depending on the type of nerve block, your pain may be numbed for a short time or a long time.
Nerve blocks for chronic pain may work for 6 to 12 months. They may have to be repeated.
Why It Is Done
Nerve blocks are used to diagnose the causes of pain. They also are used to treat chronic pain when drugs or other treatments cause bad side effects or do not control pain.
How Well It Works
Nerve blocks often relieve pain. They work well in pain control for people who have advanced cancer, painful nerve conditions.1
Nerve blocks work especially well for some types of cancer pain, such as pain from cancer in organs such as the pancreas.2
Nerve blocks can cause serious complications, including paralysis and damage to the arteries that supply blood to the spinal cord. Other possible side effects include severely low blood pressure (hypotension), accidental injection of the alcohol or phenol into an artery, puncture of the lung, damage to the kidneys, diarrhea, and weakness in the legs.
Nerve blocks are not recommended if you have a disease that affects blood clotting, are taking blood-thinning drugs (such as heparin or warfarin), have a bowel obstruction, or have any type of uncontrolled infection.
What To Think About
Doctors have begun to use extreme cold or heat in nerve blocks instead of drugs or chemicals. Cryoanalgesia is the use of extreme cold. A probe is placed very close to the nerve, and the temperature is lowered for 60 to 120 seconds, often in several cycles. Radiofrequency denervation is the use of extreme heat. A probe is placed close to the nerve, and radio waves are used to generate extreme heat at the tip of the probe for 40 to 90 seconds.1
A nerve block may cause temporary muscle paralysis or a loss of all feeling in the affected area or in the surrounding area.
Although nerve blocks can improve pain control, they do not help people to live longer.3
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Fausett HJ, Warfield CA (2002). Nerve blocks: An overview. In CA Warfield, HJ Fausett, eds., Manual of Pain Management, 2nd ed., pp. 293–299. Philadelphia: Lippincott Williams and Wilkins.
De Leon-Casasola OA (2000). Critical evaluation of chemical neurolysis of the sympathetic axis for cancer pain. Cancer Control, 7(2): 142–148.
Wong GY, et al. (2004). Effect of neurolytic celiac plexus block on pain relief, quality of life, and survival in patients with unresectable pancreatic cancer. JAMA, 291(9): 1092–1099.
Other Works Consulted
Jain S, Gupta R (2001). Neurolytic agents in clinical practice. In SD Waldman, ed., Interventional Pain Management, 2nd ed., pp. 220–225. Philadelphia: W.B. Saunders.
|Author||Shannon Erstad, MBA/MPH|
|Editor||Kathleen M. Ariss, MS|
|Associate Editor||Pat Truman, MATC|
|Primary Medical Reviewer||Anne C. Poinier, MD - Internal Medicine|
|Specialist Medical Reviewer||Michael Seth Rabin, MD - Medical Oncology|
|Last Updated||October 30, 2007|