Facet Joint Injections

What are they?

Zygapophysial joints, better known as facet or “Z” joints, are located on the back (posterior) of the spine on each side of the vertebrae where they overlap the neighboring vertebrae. The facet joints provide stability and give the spine the ability to bend and twist. They are made up of the two surfaces of the adjacent vertebrae, which are separated by a thin layer of cartilage. The joint is surrounded by a sac-like capsule which is filled with synovial fluid (a lubricating liquid that reduces the friction between the two bone surfaces when the spine moves and also nourishes the cartilage.)


Your physician may order diagnostic tests such as magnetic resonance imaging (MRI) or computerized tomography (CT) scans to look at the structures of the spine. A problem (such as inflammation, swelling, or arthritis) in the facet joint may cause low back pain. If these diagnostic tests show an abnormality in a facet joint, it may be the source of the pain. A physical exam may also support the diagnosis.

Injections Procedure Overview

The injection is usually performed while you are lying on your stomach under x-ray imaging. The procedure is performed using real-time fluoroscopy imaging where your doctor can see the structures on a TV screen. Your doctor will clean and sterilize the area of the back directly over the affected joint. After using a local anesthetic to numb the skin over the injection site, a needle is inserted into the facet joint. Your doctor will inject the joint with a contrast (dye) that will show up on the X-ray to ensure she has the proper site for injecting the medications. Once the proper site has been determined, your doctor will inject the anesthetic and the steroid.

After The Injection

Immediately following the procedure, you may feel a reduction or complete relief of your back pain. You probably should have someone who is able to drive you home. Once home, you can treat pain you may have at the injection site with ice or a pain medication prescribed by your doctor. It is generally recommended that you take it easy and not exert yourself for the first day. After the anesthetic component of the injection wears off, your back pain may return. It may take 3-5 days for the steroid to relieve the pain. After the first day, you can usually return to your daily activities as your pain will allow; however, you should check with your health care provider to get his or her recommendations on specific activities that will be allowed. In most cases, you can return to work the day following the injection.

Effectiveness of Facet Injections

Research has found that facet injections can relieve low back pain for longer than six months in 80% of patients who underwent the procedure.

Side Effects

There is a possibility of side effects with just about any medical procedure and you should always discuss that possibility with your physician before undergoing any treatment. Possible side effects from facet injections include pain at the injection site, bleeding, infection or a worsening of the pain symptoms. Side effects of the steroid medications used may include fluid retention, weight gain, elevated blood pressure, mood swings and insomnia.