Injections made directly by the medial branch nerves which supply the facet joint are called medial branch blocks (MBB). Medial branch block and facet joint injections are designed to numb the nerves that supply the facet joint in an effort to alleviate pain or to diagnose the exact location of the pain. Facet injections/MBB’s are only temporary however the diagnosis confirmed by the block can then be followed by a radio frequency ablation. The procedure can be repeated.
Facet joints assist with spinal weight bearing, prevent the sliding of vertebral bones on top of one another, and limit spinal extension and rotation. The nerve supply of the facet joints is the medial branch nerves stemming from the large bundles of nerves coming off the spinal cord and supply each spinal segment. Each facet joint has two nerve supplies called the medial branch nerves from the spinal levels above and below.
Why is a Medial Branch Block Performed?
Facet arthropathies can occur anywhere in spinal cord, causing low back, neck pain and headaches. The exact cause of facet arthropathies is unknown, but they have been highly associated with arthritis, age-related degeneration and injury.
Facet arthropathy classically presents with pain in just one side of the neck or lower back, which may radiate to the upper or lower extremities, respectively. The vertebral column or spine consists of multiple facet joints. Damaged cervical facet joints may refer pain to the head, neck and shoulders. Thoracic facet joints may radiate pain to the upper back, middle back, and chest wall, and lumbar facet joints may refer pain to the back, buttocks, and thighs.