INFLAMMATORY DISEASES OF THE SPINE
Up to 71% of patients with rheumatoid arthritis have C-spine involvement.
C1-C2 instability, basilar invagination, and subaxial subluxation are common disease patterns.
Inflammatory pannus causes synovial joint destruction.
Eighty percent of patients are rheumatoid factor positive.
Rheumatoid arthritis is the most common form of inflammatory arthritis. It affects 3% of women and 1% of men. The disease frequently affects the spine. Up to 71% of patients with rheumatoid arthritis show involvement of the cervical spine. Risk factors for cervical spine involvement include female gender, positive rheumatoid factor, long-term corticosteroid treatment, peripheral joint erosions, younger age, and markers of higher disease activity including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). The most common patterns of involvement are C1-C2 instability, basilar invagination, and subaxial subluxation. Of these patterns, both C1-C2 instability and basilar invagination have become less frequently encountered as a result of improvements in pharmacologic therapy. Sudden death associated with rheumatoid arthritis, most probably secondary to brainstem compression or vertebrobasilar insufficiency, is reported.
The same inflammatory cells that destroy peripheral joints affect the synovium of apophyseal and uncovertebral joints of the spine, causing painful instability with or without neurologic compromise. The pannus, a combination of hypertrophic synovium and inflammatory cells, often causes facet joint and transverse ligament destruction, leading to painful instability. The hypertrophic tissue can also cause direct compression of the spinal cord and nerve roots at the affected levels.
Prevention of rheumatoid instability centers on control of the inflammatory component of the disease. Pharmacotherapeutic strategy initially involves the use of anti-inflammatory medication and application of disease-modifying antirheumatic drugs (DMARDs). Over the past decade, biologic agents such as infliximab, etanercept, and adalimumab have been shown to be effective in helping to control disease activity and suppress joint destruction. Biologic agents work by targeting specific steps in the inflammatory process, unlike DMARDs, which target the entire immune system. Furthermore, evidence has shown that biologic agents help prevent new cervical lesions from developing in patients with rheumatoid arthritis.
From 7% to 34% of patients present with neurologic problems. Documentation of neurologic function can be difficult because loss of joint mobility leads to general muscle weakness. Although many patients complain of nonspecific neck pain, atlantoaxial subluxation is the most common cause of pain in the upper neck, occiput, and forehead in patients with rheumatoid arthritis. Symptoms are aggravated by motion. Increased compression of the spinal cord can result in severe myelopathy with gait abnormalities, weakness, paresthesia, and loss of dexterity. Findings may also include Lhermitte sign (a tingling or electrical feeling that occurs in the arms, legs, ...