What are facet joint injections?
Glucocorticoids or steroids have been injected in spinal facet or zygapophyseal joints for joint related arthritis of the spine. These joints are diarthrodial joints covered by synovial lining, and whose bony interior is covered by hyaline cartilage. Although there is less supportive literature backing the effectiveness of injecting facet joints, these interventions have been standard practice in many interventional pain clinics and institutions for joint mediated or arthritic pain. Using fluoroscopy, the needle is visualized and guided into the joint space. These injections can be performed for diagnostic purposes using an anesthetic, or for therapeutic purposes using glucocorticoid medications.
Medial nerve branch blocks target the medial branch of the dorsal rami. These medial branches innervate the facet joints. Injections targeting this nerve can be performed for diagnostic and therapeutic reasons. Each joint is innervated by two medial branches; for example, the L2 and L3 medial branches innervate the L3 to L4 facet joints, and the L4 and L5 medial branches innervated the L5 to S1 joint. A similar approach to medial branch blocks or steroid injections is radiofrequency ablation, which is a procedure that may provide more sustained relief without involving steroid administration.