Facet joint block is a procedure designed to provide diagnostic and therapeutic information about pain emanating from a facet or zygoapophyseal joint.

Under live and intermittent fluoroscopy a needle is advanced into the facet joint(s). After verification of placement using radiopaque contrast, a small amount of medication is injected into the joint. For diagnostic purposes the medication used is a local anesthetic. For therapeutic effect, steroid medication may be administered concurrently.

An initial report is obtained from the patient concerning the change in their pain post-injection compared to pre-injection. A second report is obtained 1 – 2 weeks later.

Facet joint blocks are useful in determining the role facet joints play in the causation of mechanical spine pain.