Lumbar Medial Branch Block

A lumbar medial branch block is an injection of numbing medication into the medial branches or nerves that give feeling to the facet joints in the spine. Due to its numbing capabilities, the lumbar medial branch block can be used to diagnose and treat pain in medial branches in the lumbar region of the spine, or low back.

The facet joints (zygapophysial joints), located where the vertebral bones touch, provide motion between vertebrae. Pain in the medial branches of the facets is often a consequence of degenerative processes associated with aging, such as osteoarthritis and spinal disc degeneration. The spine may begin to collapse, reducing the space between neighboring vertebrae. Such processes increase inflammation and friction in the facet joints, and may lead to buildup of scar tissue, all of which have the potential to irritate and compress the medial branch nerves.

By numbing a medial branch, the practitioner can assess whether the pain is originating from the nerve, and determine whether continued nerve blocks would be of benefit. A successful medial branch block may also make the patient eligible for longer-lasting pain relief procedures, such as radiofrequency ablation.

A medial branch block is an outpatient procedure that takes only minutes to perform. First, the skin over the area to be injected is cleansed with antiseptics, and treated with local anesthesia. Then, the physician injects numbing medication into the medial branch nerve(s) using fluoroscopic (real-time x-ray) guidance to ensure accuracy.

After a short recovery period, the patient is released the same day. The patient will be asked to rate his or her pain after the procedure and in follow-ups.

A successful medial branch block is characterized by a pain reduction of at least 50%. Since the effects of the block are temporary, the patient’s pain relief can be maintained with a series of these injections. At that time, the practitioner may also offer the patient longer-lasting treatments that produce longer-lasting pain relief.

Medial branch blocks:

• Are minimally invasive.
• Are conducted on an outpatient basis.
• Require very little recovery time.
• Serve as a screening method for longer-lasting pain relief procedures.

The medial branch block is a relatively safe and common procedure. However, like any medical treatment, it can lead to complications, such as:

• Infection.
• Damage to surrounding tissues, such as spinal membranes.
• Temporary soreness around the injected area.