Medial branch nerve blocks are usually used as a diagnostic procedure to determine if the facet joints in your spine are causing pain. Facet joints are located in the back of the spine from the neck to the lower back. It is common for facet joints to become arthritic and painful, sometimes as early as in a person’s 20s. Facet joint pain is typically located in the low back or neck, sometimes with radiation to the buttocks or shoulders. It is usually made worse by bending backwards at the waist or leaning forward, such as when standing at a sink. A medial branch nerve block is a procedure in which an anesthetic is injected near the nerves connected to your facet joints. Typically, several levels of the spine are injected in one procedure. If you experience significant pain relief immediately after the injection, then the facet joint is likely to be the source of your pain.
The procedure is primarily diagnostic, meaning that if you have pain relief after the medial branch nerve block, then you may be a candidate for a subsequent procedure called a Radiofrequency Ablation, or Rhizotomy, for longer pain relief.