A facet joint injection is an injection which you pass a needle to the facet joint. The needle is inserted to the joint and a small amount of lidocaine or another anesthetic agent is introduced along with anti-inflammatory medication. The anti-inflammatory cuts that inflammatory process and decreases the pain.
Alternatively, you could do what’s called a facet joint injection not directed at the facet joint, but at the nerve going to the facet joint. This is called a medial branch block and what it does is it blocks the nerve that sends the painful signals to the brain that the facet joint hurts. So if you block the perception of that pain, the facet still looks the same – still has the same inflammation – but the brain doesn’t perceive it, and therefore eliminates the pain. In certain cases with a medial branch block, the branch block is more of a diagnostic tool.
In certain cases with a medial branch block, the branch block is more of a diagnostic tool. Although, in many cases it can be therapeutic in and of itself. But often times, doesn't give you prolonged relief. In that case, a second procedure can be performed in which another needle is placed near the nerve – near the medial branch – and the needle tip is heated up to such a temperature to destroy the nerve. The nerve will eventually likely grow back; it could take upwards of a year or more, but for that period there’s no signals being sent by that facet joint, which is to the brain that it hurts and there can be quite positive reduction in pain.