Facet Joint Injection
(Medial Branch Block; Zygapophysial Joint Injection; Z-Joint Injection)
by Pamela Jones, MA
The spine is made up of bones called vertebrae. Each vertebra has two pairs of facet joints. One pair points up and connects with the vertebrae above. The second pair points down and connects with the vertebrae below.
These joints have cartilage, ligaments, and a surrounding sac of fluid to allow smooth movement. Injury to any of these structures may cause swelling and pain. The swelling may also put pressure on nerves as they exit the spinal cord. This may result in local pain or pain that shoots down the limbs.
A facet joint injection is a shot directly into the joint. The shot will have a small amount of a numbing medicine (anesthetic) and/or medicine to reduce swelling.
In some cases, the injection is done just beside the joint at a tiny nerve branch that supplies the joint. This is called a medial branch block. This is often done as a diagnostic test with just a numbing medicine to see if the targeted area is the source of pain.
Reasons for Procedure TOP
It is not always clear what causes back or neck pain. It may be caused by problems of the joint, nerves, or other structure, such as muscles or ligaments. A facet joint injection of a numbing medicine may be used to confirm or disprove the joint as the cause of pain.
If the facet joint is the cause of pain, injections may be used to deliver steroid medicine to try to help control pain and inflammation.
Possible Complications TOP
Complications are rare. But, no procedure is completely free of risk. If you are planning to have this injection, your doctor will review a list of possible complications, which may include:
Smoking may increase your risk of complications.
Your doctor may not want to do this injection if you:
Talk to your doctor about these risks before the procedure.
What to Expect TOP
Prior to Procedure
Your doctor may begin with conservative treatment (eg, rest, medicine, physical therapy, exercise).
Before the injection, your doctor may:
Talk to your doctor about your medicines. You may have to stop taking some medicines up to one week before the procedure, like:
Additional considerations include:
You will be awake during the procedure. A local anesthetic will be used to numb the skin before the injection. Your doctor may also give you additional medicine to help you relax.
Description of Procedure TOP
You may have devices attached to help monitor your blood pressure, heart, and oxygen levels. You will be asked to lie on your stomach or side on an x-ray table. The skin around the injection site will be cleansed with an antiseptic. A local anesthetic may be given to numb the area.
The doctor may inject a contrast dye. This dye will help to highlight the joint in an x-ray and help ensure the correct placement of the injection. This type of x-ray is called a fluoroscopy. The doctor will place the needle into or around the joint and inject the anesthetic medicine. You will be asked about your pain relief during the procedure.
If you have pain relief after the injection, this may mean the problem is due to the facet joint. A second injection with a steroid medication may be done to reduce inflammation and swelling.
If you do not have pain relief after the first injection, your doctor may:
Immediately After Procedure TOP
You will stay at the clinic for a few minutes after the injection.
How Long Will It Take? TOP
The injection only takes a few minutes. The entire visit may be 30-60 minutes. The length of time will depend on the number of injections needed.
How Much Will It Hurt? TOP
This is a deep injection so you may have some discomfort. Ask your doctor about medicine to help with the pain after the procedure.
Post-procedure Care TOP
You may have complete or partial pain relief.
At the Care Center
Your doctor will assess your level of pain relief. You may be asked to do movements that had been causing pain before. This can help to see if you feel better after the injection.
When you return home, take these steps:
If you have diabetes, monitor your blood sugar levels more carefully a few weeks after an injection. The medicine that was injected may affect your blood sugar levels.
Call Your Doctor TOP
Call your doctor if any of these occur:
If you have an emergency, call for medical help right away.
American Academy of Orthopaedic Surgeons
American Chronic Pain Association
The Arthritis Society
Lumbar zygapophysial (facet) joint injections. North American Spine Society website. Available at: http://www.spine.org/Documents/facet_joint_2006.pdf . Accessed March 5, 2012.
Spinal injections. American Academy of Orthopedic Surgeons website. Available at: http://orthoinfo.aaos.org/topic.cfm?topic=A00560 . Accessed March 19, 2012.
Spinal injections. Rehabilitation Institute of Chicago Spine and Sports Rehabilitation Center website. Available at: http://www.ric.org/conditions/sportsmed/SpinalInjections.aspx . Accessed March 19, 2012.
Last reviewed June 2013 by Teresa Briedwell, DPT, OCS
Last Updated: 6/20/2013