Medial Branch Blocks/Facet Injections


A facet block is an injection of local anesthetic and steroid into a joint in the spine. A medial branch block is similar but the medication is placed outside the joint space near the nerve that supplies the joint called the medial branch (steroid may or may not be used). You may require multiple injections depending upon how many joints are involved.Facet blocks and medial branch blocks are typically ordered for patients who have pain primarily in their back coming from arthritic changes in the facet joints or for mechanical low back pain.

What happens during the actual procedure?

A facet block or medial branch block may be therapeutic and/or diagnostic. One of three things may happen.

After signing a consent form and checking your blood pressure the procedure will be done in the fluoroscopy (x-ray) room with you lying on your stomach. For procedures in the neck an intravenous is started. The back is then cleansed with an antiseptic soap. Sterile drapes are placed. The skin is anesthetized (numbed) with a local anesthetic. This is felt as a stinging or burning sensation. Using x-ray guidance, needles are then advanced to the appropriate locations (the joints or the medial branch). Once the needles are in the proper location local anesthetic with or without steroid is injected through the needles and the needles are removed. Your skin will be cleansed and bandages will be applied. (The bandages can be removed on the next morning). Your blood pressure will be checked and you will be discharged to leave with your ride after the physician authorizes your discharge.

What is axial spine pain?
Pain localized to the low back or neck is known as axial pain. This pain may even extend
towards the shoulders in the neck or the buttocks in the back. The small joints of the
spine that allow you to bend, flex, and twist are called the facet joints. These are
frequently the cause of axial spine pain as they develop arthritis and inflammation with
aging. In low back pain, it has been estimated that the facet joints are the cause in up to
45% of cases.
What are the facet joints?
The main function of the facet joints is to limit rotation and resist compression when
extending the back. Facet joint pain results from conditions that increase the load on
them, such as arthritis, decreased disk space, and increased extension (as in obesity).
What are medial branch blocks?
Medial branches are the nerves that supply the facet joints. Since we cannot make the
spine younger or less degenerative, what we aim to do is turn off the painful signal that
comes from those joints. The medial branch nerves are the messengers of this painful
signal, and by blocking them with numbing medicine we can oftentimes turn off the pain.
These nerves do not provide any other significant function other than to tell you that you
have arthritis in your joints. This is one instance where we want to ‘kill the messenger’,
so to speak.
What should I expect during medial branch blocks?
During the procedure, the doctor will first clean off the skin and use X-ray guidance to
identify the area where the medial branch nerves live. Then, the doctor will numb up the
skin with a pinch and a burn at four sites. The doctor then places the needles down to the
area where the nerves run and double-checks with more X-rays. Once in satisfactory
position, the doctor injects a long-acting numbing medication onto the medial branch
What should I expect after medial branch blocks?
This is a diagnostic procedure, which means that we are testing to see if it takes away
your pain. As such, you will be asked to fill out a pain diary documenting any relief you
experience every hour for the first 12 hours after the injection, and also at several time
points thereafter. We want you to be active during this time to really test whether or not
the injections relieve your pain.
Ok, the medial branch blocks took away my pain temporarily. Now what?
If the medial branch blocks relieve your pain while the numbing medicine is working,
then you may be a candidate for a long-acting procedure called a radiofrequency ablation
or rhizotomy.



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