Dr. Moldover: Facet Joint Injections

Facet Joint Injections

Facet joints are a common source of pain, but are difficult to diagnosis based on symptoms, physical findings, and imaging studies. The only way to be sure if these joints are the source of the pain is to inject them under x-ray guidance. It is possible to inject into the joint, or to block the nerves going to the joint.

Intra-articular facet joint injection: a thin needle is inserted into the joint and a small amount of contrast material is injected to prove that the needle is really inside the joint. Then a combination of local anesthetic and corticosteroid is injected (like injecting a knee or shoulder). The anesthetic produces a temporary numbness which should relieve the pain if the joint is the pain generator. The corticosteroid reduces inflammation in the joint, providing longer lasting relief and allowing the patient to tolerate physical therapy better.

Medial branch block: each facet joint has two nerves (medial branches) which carry pain impulses to the brain. In this injection, a needle is placed on each nerve and local anesthetic is injected. If the joint is the pain generator, then the pain will be relieved for the duration of the anesthetic. This is primarily a diagnostic procedure since the relief is not long lasting. If there is good relief, and if the patient has not responded to physical therapy and other measures, then we can proceed to dennervation of the facet joint.

Radiofrequency: If the facet joint has been clearly established as the pain generator, and if sustained relief cannot be obtained with physical therapy, medication, and other measures, then the nerves which carry the pain sensation from the joint to the brain may be “burned” by exposure to radiofrequency. This can be done by performing a medial branch block with a special insulated needle through which a radiofrequency probe can be passed. The nerve is then exposed to radiofrequency current. The current produces very localized heating which damages the nerve. The effect lasts for several months to a year or more. The nerve eventually grows back and the pain returns. The procedure can be repeated any number of times.