by Jones P
(Medial Branch Block; Zygapophysial Joint Injection; Z-Joint Injection)


A facet joint injection puts numbing (anesthetic) and steroid medicine into the facet joint. These are small joints that are located between each vertebra on the back of the spine.

In some people, the injection is given just at a tiny nerve branch that supplies the joint. This is called a medial branch block.

Facet Joint Injection
facet joint injection
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Reasons for Procedure

A facet joint injection is done to find out if a joint is the cause of back or neck pain. It may also be done to ease pain and swelling in a joint.

Possible Complications

Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:

  • Excess bleeding at the injection site
  • Allergic reaction to the medicine used
  • Infection
  • Pain that worsens
  • Nerve injury
  • Muscle weakness

Smoking may raise the risk of problems.

What to Expect

Prior to Procedure

The care team may meet with you to talk about:

  • Anesthesia options
  • Any allergies you may have
  • Current medicines, herbs, and supplements that you take and whether you need to stop taking them before the procedure
  • Fasting before the procedure, such as avoiding food or drink after midnight the night before
  • Whether you need a ride to and from the procedure
  • Tests that will need to be done before the procedure, such as images of the spine


The doctor may give local anesthesia. The area will be numbed.

Description of Procedure

You will be asked to lie on your stomach or side on an x-ray table. The doctor may inject a contrast dye. It will help locate the joint on an x-ray. This will help guide the injection. The needle will be inserted in the joint. The anesthetic medicine will be injected. You will be asked whether the pain is relieved. If the injected eased pain, a second injection may be given to ease swelling.

If the pain is not eased by the injection, the doctor may:

  • Try another facet joint
  • Inject more medicine
  • Try a different spine injection, such as a medial branch block

The needle will be removed. A small bandage may be placed over the site.

How Long Will It Take?

30 minutes

Will It Hurt?

Pain is common at the injection site. It may last several hours. Medicine and home care can help.

Post-procedure Care

At the Care Center

A physical exam may be done to find out how much pain has been relieved.


It will take a few hours for the injection site discomfort to go away. Physical activity may need to be limited.

Call Your Doctor

Call the doctor if you are not getting better or you have:

  • Signs of infection, such as fever and chills
  • Redness, swelling, increasing pain, bleeding, or discharge from the injection site
  • Pain that you cannot control with medicine
  • Nausea or vomiting
  • Weakness or numbness
  • Headache that does not go away
  • Loss of bladder or bowel control

If you think you have an emergency, call for medical help right away.


American Chronic Pain Association 

Ortho Info—American Academy of Orthopaedic Surgeons 


Arthritis Society 

Health Canada 


Chronic low back pain. EBSCO DynaMed website. Available at: Accessed September 30, 2020.

Facet joint injections and medial branch blocks. Bupa website. Available at: Accessed September 30, 2020.

Last AR, Hulbert K. Chronic low back pain: evaluation and management. Am Fam Physician. 2009 Jun 15;79(12):1067-1074.

Lumbar zygapophysial (facet) joint injections. Know Your Back—North American Spine Society website. Available at: Accessed September 30, 2020.

Spinal injections. American Academy of Orthopedic Surgeons Ortho Info website. Available at: Accessed September 30, 2020.

Revision Information