Under normal biomechanics, the joint limits motion between vertebras and assists in weight bearing. Following injury, osteoarthritis and a multitude of other spine related disorders the joints can become painful as a result of increased weight bearing. There is no correlation between facet joint pain, x-rays, MRIs or CT scans. The diagnosis and treatment is determined by facet joint block or blocking the nerve to the joint under x-ray guidance.
The joint approach (facet joint injection) entails placing dye, local anesthetic and steroid into the synovial sac of the joint. If the pain is improved for the duration of the local anesthetic on the day of injection, this is considered diagnostic. If severity and duration of relief is determined diagnostic the steroid may help reduce the pain in 2-5 days.
The nerve approach (diagnostic facet nerve block, diagnostic medial branch block) involves placing a local anesthetic agent on to the nerve under fluoroscopy guidance. Patient response is evaluated by duration and amount of pain reduction. If diagnostic, a confirmatory block is then performed. Ultimately the nerve signal may be disrupted using radiofrequency waves.