figure – Intra-articular facet joint block
A lumbar medial branch block (MBB) or an intra-articular facet joint injection is a diagnostic procedure used to determine the potential cause of chronic lower back pain related to the lumbar area of the spinal column. It involves injection of a local anaesthetic and steroid either into the joint, or directed to nerves innervating these joints. The nerves exist in pairs on the posterior portion of the spinal column. The only function of these small nerves is to carry pain signals from the area of the facet joint toward the brain. Facet joints are found posteriorly (or behind) and in between the vertebrae. These joints stabilize the spine and allow or limit rotation of the spine.
When a facet joint is irritated, inflamed, or damaged, either by trauma or a degenerative condition like osteoarthritis, it may lead to pain involving the buttocks, abdomen, low back, groin, and legs. If a lumbar medial branch block does not decrease pain levels, the facet joint is most likely not the origin of back pain. If a lumbar medial branch block produces a dramatic decrease in pain levels, the facet joint is most likely the reason for the back pain. Thus, the initial diagnostic block is indicated to help define the primary source of the pain. If positive, then a procedure called a radiofrequency (RF) denervation that heats and lesions the nerve supplying the facet joint, can be performed to extend the pain relief benefits derived from the initial diagnostic procedure.
Citation: Jadon A (2016) Low Back Pain due to Lumbar Facet Joint Arthropathy and its Management. Gen Med (Los Angeles) 4:252. doi: 10.4172/2327-5146.1000252