Facet Injections/Medial Branch Blocks

A medial branch block is an injection of local anesthetic and cortisone placed outside the joint space near the nerve that supplies the joint called the medial branch. Multiple injections may be required depending on the number of joints involved.

Facet medial branch blocks are typically ordered for patients who have pain primarily in their back coming from arthritic changes in the facet joints or for mechanical low back pain.

The purpose of a facet block or medial branch block can be both therapeutic and diagnostic. Here’s what can happen:

• The pain does not go away, indicating that the blocked facet joints are likely not the source of the pain. This has diagnostic value.
• The pain goes away and stays away for a few days to a week, but the original pain returns. This suggests that the block was also of diagnostic value, and the pain is likely coming from the joints.
• The pain goes away after the block and remains absent for a few weeks to a few months. This indicates that the block was of therapeutic value, and the steroid had a long-lasting effect on the pain.

If you experience significant and lasting benefits from the facet injections, the block may be repeated. Alternatively, another procedure called radiofrequency lesioning may be performed, which can provide months to years of pain relief.

What Are the Risks of the Procedure?

The risks associated with the procedure are rare but can include bleeding, infection, nerve injury, or allergic reactions to the medications used.

Short-term side effects may occur, such as increased pain for a few days after the injection, including localized pain at the injection site. Diabetics may experience a short-term elevation of blood sugars, and individuals prone to fluid retention may notice increased fluid retention for 1-2 weeks.

Will the Injection Hurt?

Most patients receive intravenous sedation, making the procedure easy to tolerate. However, individual responses can vary.

What Happens During the Actual Procedure?

During the actual procedure, you will be positioned on your stomach in the fluoroscopy (X-ray) room. For procedures in the neck, an intravenous line may be started. The back will be cleansed with antiseptic soap, and sterile drapes will be applied. Using X-ray guidance, needles will be advanced to the appropriate locations, and local anesthetic with steroids will be injected through the needles. The needles will then be removed, and the skin will be cleansed and bandaged. You will have your blood pressure checked, and upon authorization from the physician, you will be discharged to leave with your accompanying ride.