The facet joint is on the back of the spinal vertebrae, and acts like a hinge between vertebral segments. Facet joints are located between each vertebra and provide flexibility to the spine that allows you to bend and twist your back.
Each vertebra has two sets of facet joints, one facing upward (superior articular facet) and one downward (inferior articular facet) on each side (right and left). These joints act like hinges linking the vertebra together to form your spine. In order for the facets to be an effective hinge, each cartilage-coated joint is surrounded by a capsule of connective tissue and fluid that lubricates the joint allowing them to smoothly glide against each other. The nerve supplying the joint is called a medial branch.
Sometimes, facet joint problems can develop from arthritis or injury.
Facet joint and medial branch blocks are used for patients with pain stemming from inflammation or irritation of the facet joints. These patients normally do not respond to other conservative means, such as oral anti-inflammatory medication, rest, or physical therapy.
These procedures usually are performed for management of severe acute or chronic pain affecting the back or neck. They may also be performed for testing purposes by providing valuable diagnostic information about your condition. For example if your back pain or neck pain responds to a therapeutic injection, that can provide valuable information to the surgeon that a specific facet joint level is actually the pain generator.
A facet block is an injection of local anesthetic and steroid into the facet joint in the spine. A medial branch block is similar but the medication is placed outside of the joint near the nerves that supply the joint called the medial branch.
Based upon your symptoms or diagnostic tests that show an internal image of your spine, the injection can be directed into the facet joint or can target the nerves close to the joint, thus, a facet joint block or facet joint nerve block, called a medial branch block.
During the injection procedure, the patient lies face down. Using a C-arm for X-ray guidance, the spinal injectionist identifies the specific level of the spine that will receive the injection. After cleaning the skin and placing sterile drapes, the physician numbs a small area of skin. Most patients will note that the initial sensation of the numbing medicine is perhaps the only discomfort felt from the injection procedure.
Using X-ray guidance of the C-arm, the physician then guides a small needle to either the facet joint or the medial branch. In confirming the correct needle placement, the injection may initially create a response, which could be identical to the pain under investigation, similar but not identical, or a different or new sensation. The medication is then injected around the facet joint or near the nerves supplying the joint.
There will be a short recovery time in a nearby room where you may sit in a recliner and your blood pressure will be checked and you will be monitored for any complications or side effects. Typically, you will be allowed be be driven home within an hour.
Facet joint blocks or medial branch blocks can provide pain relief that lasts from days to years. If you get good, lasting benefit from the injections, the procedure may be repeated. If you get good, short-term benefit, you could be considered for another procedure called facet rhizotomy (radiofrequency ablation), which may provide longer-term relief of months to years. If you do not get any benefit from the procedure, the block still has diagnostic value in that it means that the pain is likely not coming from the targeted facet joints.