Reason for the procedure
Your health care provider has requested that you have medial branch nerve blocks. The nerve blocks numb the medial branch nerves so they cannot carry pain signals from the small facet joints in your back to the brain. The procedure may need to be performed more than once and at many sites in the spine, depending on the location of your pain. This procedure also may help your health care provider find out whether you are a candidate for further treatment to help manage your pain.
Medial branch nerves
The joints in the spine are called facet joints. Each vertebra has two pairs of facet joints. These joints support your spine when you bend or twist. Each facet joint has two small medial branch nerves that carry pain signals to the brain (Figure 1).

The procedure
You may be asked to change into a gown and use the restroom. A member of your health care team will take you to a procedure room. You will be asked to lie facedown on a table. A variety of health care providers may participate in the procedure. You will be fully awake during the entire procedure. The procedure will be performed using a special X-ray machine (fluoroscopy). The procedure usually lasts 15 to 30 minutes. The area to be injected will be cleansed with Chloraprep solution. A sterile draping of a square cloth-like material is placed against your skin, over the area where the procedure will be done. This material can sometimes stick to the skin.


The area to be injected is numbed with medication to help make the procedure as comfortable as possible. This local anesthetic helps numb the skin and tissues where the needle will be inserted. You may have some discomfort during the injection. If you experience discomfort, tell your physician. Hneedle-placemente may give you more local anesthetic to make you more comfortable. Once the area is numb, usually two needles are inserted into the medial branch nerves of the facet joints your physician feels are causing your pain. It is possible you may have more than two needles inserted, depending on where your pain is located. The needles are placed alongside the medial branch nerves (Figure 2), away from the spinal cord or large spinal nerve roots. A small amount of local anesthetic is placed through the needles. This medication helps numb or block the nerves so they can’t deliver pain signals to your brain.

After the procedure
You may stay in the area and rest quietly until you feel well enough to leave. For some people, this is 10 minutes; for others, it can be longer.
The injected area may be numb for one hour or more, and the site may be sore for 1 to 2 days. A bruise may appear at the injection site.