Facet arthrosis is a common condition affecting the spine, representing the degenerative changes associated with osteoarthritis in the small joints of the back. These joints are a frequent source of chronic back and neck discomfort, impacting mobility and quality of life. Understanding the structural components involved and the process of their breakdown is the first step toward managing the resulting pain. This article will explain the anatomy of the facet joints, explore the factors that lead to their degeneration, describe the symptoms, and detail the non-surgical treatment options.
Understanding Facet Joints and Arthrosis
The spine is a complex structure where two adjacent vertebrae connect to form a three-joint complex, featuring the intervertebral disc at the front and a pair of facet joints at the back. These joints, also known as zygapophyseal joints, are located on either side of the spinal column. They guide the spine’s movements while limiting excessive rotation. Each facet joint is a synovial joint, encased in a fibrous capsule and containing synovial fluid for lubrication. The bony surfaces are covered with articular cartilage, which acts as a shock absorber and allows the vertebrae to glide smoothly.
Facet arthrosis refers to the progressive deterioration of this protective cartilage layer. Over time, constant stress causes the cartilage to thin and fray, reducing its ability to cushion the bone ends. This leads to friction between the underlying bone surfaces, causing irritation, inflammation, and the formation of osteophytes, or bone spurs. These changes can occur in the cervical (neck), thoracic (mid-back), or lumbar (lower back) regions. The resulting inflammation within the joint capsule sends pain signals through the medial branch nerve.
Primary Causes and Risk Factors
The most significant factor contributing to facet arthrosis is the natural process of aging. As the body ages, the quality and thickness of the articular cartilage diminish, making the joints susceptible to degenerative changes. Spinal trauma, such as previous accidents or injuries, can also accelerate the deterioration of the joint structure.
The mechanics of the spine also play a substantial role, particularly the integrity of the intervertebral discs. When a disc degenerates, it loses height and stability, placing an increased and uneven mechanical load onto the posterior facet joints. This abnormal movement pattern contributes directly to the breakdown of the facet cartilage. Repetitive stress from certain occupations or activities involving heavy lifting, twisting, or prolonged poor posture can also exacerbate joint wear.
Recognizing Symptoms and Diagnostic Procedures
The symptoms of facet arthrosis involve localized pain, described as a dull ache or throbbing discomfort, felt directly over the affected joint in the back or neck. Stiffness is a hallmark symptom, most noticeable in the morning or following periods of inactivity, improving after movement. The pain worsens with activities that compress the joints, such as standing for long periods, bending backward (extension), or twisting the torso.
Pain can also be referred to other areas of the body depending on the joint’s location. Lumbar facet arthrosis may cause pain that radiates into the buttocks, groin, or the back of the thighs, but rarely extends below the knee. Cervical facet pain often presents as a headache or discomfort radiating to the back of the head, shoulder, or upper back. Diagnosis begins with a physical examination and a review of the patient’s symptoms and medical history.
Imaging tests are used to visualize the joints and confirm the presence of degenerative changes. X-rays show a reduction in joint space and the presence of bone spurs, while a Computed Tomography (CT) scan provides a more detailed look at the bony structures. The most definitive diagnostic tool is the facet joint block. This involves injecting a local anesthetic directly into the joint or onto the medial branch nerves that transmit pain signals. If the injection provides significant, temporary pain relief, it confirms the facet joint as the source of discomfort.
Managing Pain and Restoring Function
Treatment for facet arthrosis follows a conservative approach focused on reducing pain and improving joint function without surgery. Initial management involves rest, applying heat or cold packs, and using pharmacological agents. NSAIDs decrease inflammation and pain, while muscle relaxants may be prescribed for associated muscle spasms.
Physical therapy is a cornerstone of recovery, aiming to stabilize the spine through targeted exercises. Therapists strengthen the core and paraspinal muscles to support the spinal column, offloading pressure from the degenerated joints. They also improve posture and flexibility to restore range of motion. If conservative measures fail, interventional pain management procedures may be utilized.
A common procedure is a corticosteroid injection, which delivers anti-inflammatory medication directly into the facet joint. For longer-lasting relief, radiofrequency ablation (RFA) can be performed. RFA uses heat to temporarily deactivate the sensory medial branch nerves that supply the painful joint, preventing pain signals from reaching the brain. This procedure offers pain relief lasting from several months up to a year or more.