Medial branch nerves are small nerves that feed out from the facet joints in the spine and carry pain signals from those joints. (Think of “media” and its delivery of information.) Facet joint injections are often used simply to identify a pain source.
How it works: A medial branch nerve block temporarily interrupts the pain signal being carried by the medial branch nerves that supply a specific facet joint. If the patient has the appropriate duration of pain relief after the medial branch nerve block, then he or she may be a candidate for radiofrequency neurotomy. A radiofrequency neurotomy (a.k.a. rhizotomy) is an injection procedure in which a heat lesion is created on certain nerves with the goal of interrupting the pain signals to the brain. Rhizotomy can in some cases provide pain relief lasting nine to fourteen months and sometimes much longer.