What is the procedure used for?

A facet injection (facet block, Z-joint injection) is a procedure for treating pain arising from the small posterior joints of the spine. These joints can cause pain after injury or because of osteoarthritis (degenerative disease). See also microtherapy. A lumbar facet is in the lower back. A cervical facet is in the neck. A thoracic facet is in the middle part of the back.

What is the preparation for the test?

No preparation is necessary.

Please tell us what medications you are taking before your appointment, in particular if you are taking any blood thinning medicine. Also tell us if you have any allergies.

Will I have to undress?

You will be asked to remove most of your clothes, but may keep on your underpants. Buttons, clips etc on clothes show up too well on x-ray and can be confusing to interpret or hide abnormalities. You will be asked to change into a cotton gown, opened at the back.

Where will I be for the test?

You will be asked to lie face down on a fluoroscopy table. This is a hard table which can move in many directions as well as tilt. In most cases you will have a pillow placed under your stomach to straighten your back.

How is the test done?

For lumbar (lower back) injections, the doctor will clean your lower back with Betadine (a brown Iodine antiseptic). For a cervical (neck) injection, the doctor may clean your neck. The doctor guides a very fine needle down to the joints while watching on a fluoroscopy screen. This is an x-ray machine which uses low dose radiation to form a live image of the inside of the body onto a television screen. The doctor can see both the joint to be injected as well as the needle. Once in position, a mixture of Kenacort (Triamcinolone – an anti-inflammatory drug) and Marcain (Bupivicaine – a long acting local anaesthetic) are injected.

Does it hurt?

The local anaesthetic may sting for a few seconds. Sometimes the injection will cause a temporary flare-up of your symptoms. This may be a good sign, as it means the injection seems to be in the correct place. Nevertheless, most people experience little discomfort at all, which does not mean that the procedure has not worked.

How long will it all take?

5–20 minutes depending on the number of joints to be injected.

And after the test?

Even if the injection is in the right place, often there is no response for at least a day. You should keep a record for about a week, like a simple diary entry, to monitor your pain. If the pain goes away, then we know it is arising from the joint(s) that were injected. If the result is good, but the effect is temporary, a medial branch block may be useful.

Does the test use radiation?

Ionising radiation is used.