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Compare the radiographic features of inflammatory and noninflammatory spinal arthritis
Inflammatory spinal arthritis is typically related to either infection or a seronegative spondyloarthropathy. Hematogenous spread of infection usually results in osteomyelitis originating near the endplate regions with subsequent spread to the intervertebral disc. The typical radiographic appearance of osteomyelitis is disc space narrowing with poorly defined cortical endplates and destruction of the adjacent vertebrae. Although this appearance is highly suggestive of infection, other inflammatory arthropathies, such as RA (cervical spine), seronegative spondyloarthropathies, and CPPD, can rarely give a similar appearance.
Ankylosing spondylitis (AS) is associated with squared anterior vertebral bodies with sclerotic anterior corners, syndesmophytes (ossification of the annulus fibrosus), discovertebral erosions (Andersson lesions), and vertebral and apophyseal fusion. Psoriatic or chronic reactive arthritis may cause spinal changes similar to AS; however, more typical is the presence of large bulky nonmarginal paravertebral ossifications near the thoracolumbar junction. Radiographic sacroiliitis will also be present in spondyloarthropathy patients who have inflammatory spinal disease.
Noninflammatory lumbar arthritis is characterized by disc space narrowing and vacuum phenomenon, endplate proliferation, and bony sclerosis in the absence of sacroiliitis. Degenerative diseases of the vertebral column can affect cartilaginous joints (discovertebral junction), synovial joints such as apophyses, or ligaments (enthesopathy). Typically, dehydration of the disc results in cartilage fissuring, with subsequent diminution in height and vacuum phenomenon (gas within the disc) and ultimately, bony sclerosis (intervertebral osteochondrosis). Endplate bony proliferation (spondylosis deformans) is generally believed to be initiated by annulus fibrosus disruption. Ligamentous degeneration also occurs; ligamentum flavum hypertrophy may contribute to spinal stenosis, whereas ossification of the anterior longitudinal ligament is characteristic of diffuse idiopathic skeletal hyperostosis (DISH).
Radiographic features of inflammatory versus noninflammatory spinal arthritis
Radiographic features of inflammatory versus noninflammatory spinal arthritis
| Inflammatory | Noninflammatory | ||
|---|---|---|---|
| Infection | Spondyloarthropathy | ||
| Sacroiliac joints | Unilateral erosions | Erosions | Normal |
| Vertebral bodies | Irregular, eroded endplates | Squaring ± erosions | Sclerosis |
| Disc space | Narrowed | Variable | Narrowed, vacuum |
| One site | Multiple sites | Multiple sites | |
| Syndesmophytes | – | + | – |
| Osteophytes | – | – | + |
| Osteopenia | + | + | – |
| Soft tissue mass | + | – | – |
