Cervical (neck) and Lumbar (low back) Facet Joint Injections and Medial Branch Blocks

A facet joint nerve block is a type of injection used to determine if the facet joint is causing the patient’s neck or back pain. Facet joints are pairs of small joints between the vertebrae in the back of the spine. The facet joints (also called zygapophyseal joints) provide stability, while also allowing the spine to bend, flex, and twist. A variety of conditions can lead to damage to the facet joints, such as spinal stenosis or osteoarthritis, or from a trauma to the back, such as a car accident. Studies have demonstrated that facet joint injury is responsible for the chronic neck pain of whiplash in 60% of those with persisting pain, and for chronic low back pain in 5 to 40% (depending on the study) of those with post-injury low back pain.

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The nerves to the facet joints are termed the medial branch nerves and they transmit pain signals to the brain. It stands to reason that interrupting the nerves will stop the pain from facet joint injury or disease, even if the facet joints themselves cannot be healed.

The facet joint injection procedure begins with the patient lying face down on the x-ray table. The physician injects a local anesthetic, which numbs the skin and the tissue around the facet joint.  Next, the physician uses X-ray guidance, called fluoroscopy, to direct a small needle over the medial branch nerves. Needle tip position is usually checked in two different views (front to back and side to side) to confirm appropriate placement. Following this confirmation, a numbing medicine, called a local anesthetic, is slowly injected onto each targeted nerve.

Typically two nerves carry pain sensations from each facet joint to the brain. Therefore two adjacent nerves must be frozen for each joint, and so if four joints are due to be anesthetized, eight nerves must be frozen.

Directly after the procedure the patient records his/her pain score on a “pain scoring sheet” that will be given. Every 15 minutes after the procedure the patient scores his/her pain score until two sheets are completed, about 4 hours. If the facet joints on both sides were frozen, the patient may record the pain score for the left and right sides as different numbers. Also on these sheets the patient may record medication usage and any other events that may occur within the 4 hour period such as a slip and fall. For lumbar (low back) injections it is requested that the patient walk for 1 -2 minutes before recording a pain score every fifteen minutes after the injections. If it takes more than 15 minutes to reach home please ask the driver to stop the car at a parking lot to allow the patient to walk 1 – 2 minutes before each pain score recording.

The patient will then return the completed sheets to the referring physician, but should keep a copy for reference. These sheets contain the result of the test and it is important to retain these. One cannot rely on one’s memory at a later date to determine if the test was positive or negative.

If the patient experiences significant pain relief immediately after the injection, the test is often repeated for confirmation.  A different local anesthetic may be used for the second test. Two positive tests indicate that the facet joint is the cause of the patient’s pain. The patient may then be referred for any of a number of facet joint treatments which are long acting, although no known treatment will provide a cure. The patient may be a candidate for a follow-up procedure called a facet joint nerve radiofrequency neurotomy (also termed rhyzotomy or denervation) that may provide longer pain relief.


This procedure has been in use more than 20 years and so is not new or experimental. It is exceedingly rare for any permanent harm to come to any patient. The needle is guided under fluoroscopy so its position is known at all times. The needle is not near the spinal cord. The needle is near the nerves coming out of the spine, but these nerves can usually be avoided by careful technique. If the needle does approach too closely to a spinal nerve the patient may experience a shooting or electrical pain down the arm (in the case of the cervical facet joint blocks) or down the leg (in the case of the lumbar facet joint blocks). This is similar to hitting your “funny bone” of the elbow and is usually momentary but unpleasant. If it occurs, the patient should inform the physician so that local anesthetic will not be injected near this nerve with resulting numbness and weakness of the arm or leg. Even in the worst case scenario, local anesthetic is short acting and the effects would not last longer than dental freezing.

Other side effects may occur. For cervical facet joint nerve blocks, patients may be dizzy afterwards for usually a few minutes but possibly up to a few hours. This is not vertigo and not associated with nausea.

Reminder For the rare circumstance that a patient may have temporary freezing of an arm or leg, and for cervical facet joint nerve blocks where dizziness is common we ask all patients not to drive any vehicle for the remainder of the day after the procedure. By the following morning it is permissible to drive and return to usual activities.

Other side effects are those of any needle. Bleeding and bruising at the site is possible, and an infection is possible but rare. To prevent these side effects it is recommended to apply cold (ice bag) for the first 24 hours after the procedure. Cold may be ice within an ice bag applied 20 minutes and then removed for the next 2 hours and then reapplied if necessary. The patient may take his/her usual medications after the procedure but should record on the pain scoring sheets the exact time of taking each pain medication.


Pain Scoring Sheet

Markham-Stouffville Hospital

381 Church Street
PO Box 1800
Markham ON L3P 7P3

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