A facet joint injection or block involves the injection of a substance into or next to the facet joint. Typically, in a diagnostic block, local anesthetic is used. In most cases a corticosteroid is also injected. The purpose of facet joint blocks is twofold. Initially, it is a diagnostic block.
If the patient receives 50% or greater pain relief for at least two hours, there is an increased likelihood that the facet joint is important in the patient's pain syndrome. The block may then be repeated to confirm the diagnosis. The second purpose of the facet block is to reduce pain. Corticosteroids can help reduce the pain secondary to irritating substances that sensitize nerve endings.
Patients undergoing facet joint injection all receive local anesthetic to anesthetize the skin and deeper tissues. You may feel some slight pressure or discomfort. It is usually done with the patient lying on the stomach. Typically, the local anesthetic will work within 10 minutes and last up to six hours. The corticosteroid usually takes longer for pain reduction. It usually takes anywhere from one to five days for pain relief to occur if the pain is coming from the joint.
Facet joints link the bones of the spine together in the posterior or back part of the spine. Two facet joints are present at each spinal segment. They are named for the spinal bones that they connect. For example, in the neck or cervical spine the facet joints between cervical #5 and cervical #6 are called C 5-6. The facet joints are important in restricting the motion of the cervical and lumbar spine. They allow twisting, flexion and extension motion.