Facet Pain

Facet joints, also known as zygapophysial joints, are found throughout the spine. In fact, they are the most common joint in the spinal column. Facet joints are paired structures that sit posterior and lateral to the vertebral body. They are formed by the inferior and superior articular processes of adjacent vertebral bodies. Facet joints are dually innervated by paired medial branches of the dorsal primary rami. The facet joints have many encapsulated, unencapsulated and free nerve endings. They are lined with articular cartilage, allowing motion and protecting against shear forces/friction. Along with the intervertebral disk they stabilize the joint and allow for limited motion. Facet joints are potential sources of headaches, neck, shoulder, mid back, lower back and leg pain.

The C2-C3 joint is the most frequent cervical facet pain generator. The area of greatest mobility in the cervical spine is at C5-C6 and this is the second most frequent cervical facet joint that acts as a pain generator. The greatest degree of motion and strain in the lumbar spine is at the lowest two facet joints (L4-L5) and (L5-S1)

Facet Joint - C2

In patients with chronic neck, mid, or upper back pain, the prevalence of facet joint arthropathy can range from 40- 60 percent. The prevalence of lumbar facet joint pain in the general population is 10-15 percent.

Causes of cervical facet pain include whiplash due rapid deceleration injuries. Causes of both cervical and facet joint pain can include repetitive strain and intervertebral disc degeneration. Chronic strain can cause fluid collection and joint distension. Other causes include inflammatory arthritis and pseudocysts. Facet arthropathy in conjunction with other spine pathology can lead to radicular pain. Inflammatory mediators such as prostaglandins, interleukin-6 and tumor necrosis factor-alpha can be found in facet cartilage. Leakage of these substances through the joint capsule can contribute to radicular pain.

Diagnosis of facet pain typically involves a physical exam by a qualified physician. X-rays are not usually very sensitive but may demonstrate degenerative changes such as sclerosis and hypertrophic overgrowth. CT and MRI scans are more sensitive and may reveal hypertrophic osteophyte growth, subchondral sclerosis, bone marrow edema, joint space narrowing or widening, effusions and periarticular soft tissue edema. The level of symptomology and radiographic findings do not always correlate. The most reliable method to establish the facet joint as the source of pain is with medial branch or intra-articular facet joint blocks, which are typically performed with fluoroscopic (live x-ray) guidance.

After establishing the diagnosis with either an intra-articular or medial branch block, radiofrequency denervation can be performed. Prior to denervation, sensory stimulation is usually performed. Medial branch denervation is achieved by placing the tip of the RF needle at the nerve. The duration of pain relief after denervation is typically 6 months to a year.