The small joints that connect each individual segment of the spine can sometimes be a source of nerve pain related inflammation and irritation. When these facet joints become a source of pain due inflammatory conditions like arthritis, injury, or a mechanical issue related to the spine, a facet block may ease discomfort. Facet blocks (also called zygapophysial joint blocks) may be therapeutic when used to provide pain relief or serve as a diagnostic tool when used to confirm or rule out possible pain sources.
How a Facet Block Works
A facet joint block works by combining medication, usually a steroid, with a local anesthetic. It "blocks" pain by reducing inflammation that can irritate nerves and trigger pain signals from the affected area of the spine to the brain. Injections typically target the small medial branch nerves that transmit pain signals from soft tissues and facet joints. A time-release steroid is used when the blocks are used to provide extended pain relief.
How a Facet Block is Done
A long needle is inserted into center of the affected facet joint. If the block is being done for diagnostic purposes, it's placed in the facet joint suspected of being the source of back or neck pain. Some patients receive additional medication with a facet block to help them relax. A special type of live X-ray (fluoroscope) is used to guide the doctor to ensure that the needle is correctly positioned before the medication is injected.
When Facet Blocks Are Recommended
Facet blocks aren't usually recommended until patients have tried other methods of pain relief without success, such as heat or cold therapy or the use of anti-inflammatory drugs. Injections are a more direct approach to delivering medication to the affected area and may be recommended after 6-8 weeks of attempts at other methods of relief.
What a Facet Block Can Show
A facet block performed for testing purposes doesn't reveal anything specific about nerves or discs of the spine. Instead, facet blocks are used to determine how you react to symptoms once nerves are soothed from the medication. Results that a patient reports may be combined with other diagnostic tests, such as X-rays, CT scans, and MRIs, to pinpoint likely sources of pain. If a patient reports immediate relief from symptoms after the joint is numbed, it's likely the source of pain. Additional signs of facet joint pain may include:
• Radiating pain in the neck, arms, or shoulders from cervical facet joints
• Discomfort in the chest, upper back, or arms from thoracic facet joints
• Pain experienced in the lower back, legs, hips, or buttocks from lumbar facet joints
Results from facet blocks vary. There is fair to good evidence to suggest facet blocks used for short-term and long-term symptom relief of pain in the lower back may be effective enough to provide functional improvements for some patients. For diagnostic purposes, it may help determine what treatments will likely benefit a patient. As a minimally invasive procedure, facet blocks are generally considered safe and have few potential risks.