Facet blocks, also known as medial branch nerve blocks or diagnostic blocks, consist of injections into the small joints of your spine thought to be responsible for back pain.
Facet blocks are used to treat inflammation of the facet (zigo-apophyseal) joints of the spine. Facet joints are small joints at each segment of the spine that provide stability and help guide motion. At times, the facet joints can become painful due to arthritis, an injury, or mechanical stress to the back. Small nerves, called medial branch nerves, feed out from the facet joints and carry pain signals from the facet joints to the brain. Facet blocks are injections of local anesthetic (numbing medicine) into one or more of the small joints located along the side of each vertebrae on both sides of the spine in the lower part of the back.
Facet blocks usually have two goals. The first is to help diagnose the cause and location of pain and the second is to provide relief from the pain.
- Diagnosis – By placing numbing medicine into the facet joint, the amount of immediate pain relief experienced by the patient will help determine if the facet joint is a source of pain. If complete pain relief is achieved while the facet joint is numb, it means that joint is likely a source of pain.
- Pain Relief – Along with the numbing medication, a facet block also includes injecting cortisone steroids into the facet joint to reduce inflammation, which can sometimes provide longer-term pain relief.