Facet Joint Disease

Etiology

The most common cause of facet joint disease is degeneration of the spine, also known as spondylosis. When the degeneration of the joint is secondary to natural wearing and abnormal body mechanics, the condition is known as osteoarthritis (OA). The pathophysiology of OA is not entirely understood but is a complex one involving various cytokines and proteolytic enzymes as well as personal risk factors. Other causes of facet joint disease include trauma secondary to injury or sporting activities. Inflammatory conditions such as rheumatoid arthritis and ankylosing spondylitis may also contribute to the inflammation of the synovium. Subluxation of the facet joints due to spondylolisthesis can also contribute to the development of facet joint disease. Those with facet joint disease show signs of cartilage erosion and inflammation, which can lead to pain. The body also undergoes several physical changes in response to this process. Ligaments, such as the ligamentum flavum, can become thickened and hypertrophic. New bone formation around the joint can occur with the development of osteophytes or “bone spurs.” Hypomineralization can also increase subchondral bone volume.[2]

Epidemiology

The lifetime adult prevalence of low back pain in the United States is 65 to 80%.[3] This prevalence is consistent with the idea that degeneration is the leading contributory cause of facet joint disease, as the elderly population is more often affected. There have been no studies that confirm that males are affected more often than females. However, having a history of doing heavy work before age 20 increases the likelihood of developing facet joint osteoarthritis.[4] Obesity also largely contributes to osteoarthritis; thus, it is likely a contributing factor in the development of facet joint disease. Spondylolisthesis caused by degeneration is often caused by facet joint osteoarthritis and typically occurs at the L4-L5 level. Spondylolisthesis in a younger population (30 to 40) is due to congenital abnormalities, stress, or acute fractures.[4] Cervical facet disease and pain have a prevalence rate of 29 to 60% following whiplash injuries, although overall trauma is still a rare cause.[5]

History and Physical

Facet joint disease is often a clinical diagnosis, so the history and physical exam are critical. Patients who present with chronic back pain have symptoms that often overlap with other diagnoses. Facet-mediated pain is typically non-radicular. The pain is often described by patients as worse in the mornings, upon awakening, or during periods of inactivity. It may also worsen with spine extension, facet joint palpation, and rotary trunk motion. Pain can be elicited by facet joint palpation and axial loading. Reproducing the patient’s pain with Kemp’s maneuver, lateral rotation, lateral bending, and back extension suggests facet joint disease and arthropathy. In the lumbar area, this pain can be unilateral but is typically axial, with occasional radiation into the buttock, groin, and thighs and down to the knee.[6] There are reports of radiation of pain to the abdominal and pelvic areas; however, this is less frequent.[7] This “pseudo-radicular” pain does not have any associated neurological deficits. When this radiating pain is present, it can mimic sciatic pain, but this is most often in cases of osteophytes or synovial cysts.[4] It is important to rule out other causes of lower back pain, such as disc herniations, vertebral body fractures, and neoplastic causes of the patient’s pain.

Evaluation

It is often challenging to isolate facet joint disease as the sole cause of a patient’s complaint of neck or back pain. Imaging has not been proven to have much, if any, diagnostic validity. X-ray, CT, and MRI may show degeneration, joint space narrowing, facet joint hypertrophy, joint space calcification, and osteophytes; however, these findings may be present in symptomatic and asymptomatic patients. Data shows that 89% of patients in the 60 to 69 years of age population studied have facet joint osteoarthritis, although not all were symptomatic.[8]  Diagnostic medial branch blocks are the gold standard for diagnosing facet joint pain. A positive response to a set of 2 diagnostic blocks done on 2 separate occasions at 2 or more levels can confirm the source of pain. High false-positive responses are more likely if only 1 level is blocked.[9]

Treatment / Management

Conservative management is used as first-line therapy to treat facet-mediated pain. Anti-inflammatory medications, weight loss, muscle relaxers, physical therapy, and massage are used in conjunction as a multimodal approach to treating pain. When conservative measures fail, interventional procedures are considered to reduce pain, improve functionality, and reduce side effects from medications.[10] Diagnostic medial branch blocks are often performed to confirm that the pain is generated from the facet joints. Two diagnostic medial branch blocks are often an option secondary to the high (30 to 45%) false-positive success rate reported after a single block.[11] If a patient has a positive response to a set of 2 diagnostic blocks, radiofrequency ablation can then be done to ablate the medial branch nerves. Improved function and decreased pain have lasted 6 to 12 months following lumbar medial branch radiofrequency ablation.[8] Radiofrequency ablation uses heat to destroy the medial branch of the sensory nerve temporarily, thus reducing pain. The procedures mentioned above are usually done under local anesthesia and fluoroscopic guidance. Because nerves regenerate eventually, the procedure is repeatable when the patient’s pain returns, typically in 6 to 12 months. Currently, no guidelines are available to support arthrodesis when interventional procedures fail to provide pain relief. Surgery may be indicated for grade I or grade II spondylolisthesis; however, this is not first-line management and may not result in the reduction of pain.[4](B2)

Differential Diagnosis

The differential diagnosis for facet joint disease include the following:

• Sciatica
• Hip osteoarthritis
• Sacroiliac impingement
• Lumbar radiculopathy
• Myofascial pain
• Compression fractures
• Disc herniation
• Osteophytes
• Rheumatoid arthritis

Prognosis

Facet joint disease is a chronic process that can cause pain for the remainder of an individual’s lifetime. Facet joint disease is a progressive disease. The spinal and joint degeneration typically progresses as the patient ages. Maintaining a healthy weight and active lifestyle is essential to prevent the degeneration from progressing. Physical therapy and core strengthening exercises can strengthen the spine and reduce the stress on the facet joints. Interventional procedures such as medial branch blocks and radiofrequency ablations do not treat the underlining cause of the patient’s pain but allow the patient’s pain to be more manageable. Patients can have a reduction in their pain for months at a time, but some studies have shown an even longer-term decrease in pain of up to 2 years after radiofrequency ablations.[12]

Complications

Complications of treatment of facet joint pain with medial branch blocks or radiofrequency ablation are rare. Patients may have a transient increase in pain following radiofrequency ablations and medial branch blocks due to heat denervation and needle entry. Post-dural headaches, transient numbness or weakness, bleeding, infection, and increased post-procedural pain are all potential but rare complications of facet interventions.