Facet Block

A facet block is a procedure in which a mixture of local anesthetic and corticosteroid is injected into the facet joint. The facet joints are paired joints located at the back of the spine which connects the adjacent vertebrae together and provide stability for the spine. Facet joints are supplied by nerves called medial branches that carry pain signals to the spinal cord and to the brain. A medial branch block involves the injection of a local anesthetic with or without a steroid near the nerve supplying a specific facet joint. More than one injection may be needed, depending on the number of joints involved.


Facet blocks and medial branch blocks are usually indicated in patients with back pain originating from arthritic changes in the facet joints or from mechanical stress to the back. A facet block or medial branch block can be performed for the diagnosis or treatment of pain arising from the facet joints.

Before the procedure

If an injection is performed in the neck region, you should not eat or drink anything for at least 6 hours before the procedure. You can take your prescribed medications with a sip of water. However, for injections performed in the lower back region, you can eat, drink as well as take your usual medications.


During the injection procedure, you will be placed on your stomach, on the X-ray table. Your physician will clean the intended site with antiseptic and cover it with a sterile drape. A local anesthetic is then used to numb the skin. You may feel a stinging or burning sensation for a few seconds. A needle is directed into the facet joint or the medial branch nerves, under X-ray (fluoroscopy) guidance. Following this, a local anesthetic with or without steroid will be slowly injected through the needle. The needle is then removed and a bandage is used to cover the injection site.

After the procedure

Your pain may improve immediately after the injection due to the local anesthetic. When steroids are used, it usually takes about 2 or 3 days for the steroid medication to take effect and about 2 weeks to reach the peak effect.

You may experience localized pain around the injection site for which ice packs can be applied to ease the discomfort. You may experience numbness and increased pain for a few days after the injection. In diabetics, there may be a temporary rise in blood sugar level.

You can arrange for someone to drive you home after the procedure. Avoid swimming or soaking in a tub, pool or Jacuzzi and the use of any form of heat to the injection site for the rest of the day, after your procedure.

Keep a record to track the degree of pain relief and its duration.


The possible risks associated with a facet block or medial branch block injections include bleeding, infection, allergic reaction or damage to the nerves.

Call your doctor immediately if you experience severe pain, leg numbness or weakness, or signs of infection at injection site.

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