Similar to facet joint injections, medial branch block injections are also used frequently to help diagnose lower back pain that stays above the knee. These injections can be used for diagnostic as well as therapeutic purposes. The diagnostic injections introduce an anesthetic solution to the nerves to temporarily reduce pain. If the pain returns after a few hours, it indicates the pain is coming from the joints. If it has a longer lasting relief, it indicates the medial branch nerves are the source of the pain. The difference between facet joint injections and the medial branch blocks is that the medial branch nerves extend outside the facet joint and control pain sensation to the facet joint itself.
If the source of the pain is originating in the medial branch nerves, you may be a candidate for an ablation of these nerve endings either by neurolytic solution or by radio frequency lesioning. This inactivates the nerve and eliminates pain from the area for up to one (1) year after the procedure.
The purpose of performing these types of injections often refer to the degraded facet condition of the patient and/or to isolate more precisely where the pain is deriving from. Medial branch nerves do not control or give sensation to any other part of the body such as the arms or the legs and is meant to confirm arthritis of the joint.