Facet joint injections for back pain management.

The facet joints are paired joints in the back with articulation surfaces of cartilage (cushioning tissue between the bones). They are held together by a surrounding capsule. Twisting injuries can cause damage to one or both facet joints, and cartilage degeneration associated with aging may also cause pain. They often degenerate as part of an "arthritic" condition called osteo-arthritis, which may also affect the large joints.

Facet joints in the spine can become inflamed, painful and may contribute to back pain. Inflamed facet joints may act as "pain generators". In these cases facet joint injections can be performed to alleviate the pain. These injections use a combination of an anesthetic agent (lidocaine) and cortisone (depomedrol). Their therapeutic effect is to numb the source of pain and reduce the inflammation of the joint. They can also act as an diagnostic tool used to isolate and confirm the specific source of back pain for the patient.

During the procedure, a small needle is guided to the joints by X-ray fluoroscopy or CT scan control. The medication (lidocaine and cortisone) is injected into the facet joint capsule. Mild sedation may be used, but is usually not necessary. If the patient’s pain goes away after the injection, it can be inferred that the pain generator is the specific facet joint capsule that has just been injected. The lidocaine wears off after 6-8 hours, but the cortisone kicks in during the following 3 days and provides more sustained pain relief.

If the facet block procedure is effective in alleviating the patient's low back pain, it is often considered reasonable for the procedure to be done up to three times per year. There are very few risks associated with this technique.