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Information

Skull and Spine Disorders

= SPONDYLOARTHROPATHY

= group of chronic inflammatory rheumatic diseases not associated with rheumatoid factor / rheumatoid nodules

Prevalence: 0.5–1.9%

Subgroups:

  1. Ankylosing spondylitis 0.86%
  2. Undifferentiated spondyloarthritis 0.67%
  3. NO definite signs of sacroiliitis
  4. Psoriatic arthritis 0.29%
    • parasyndesmophytes
    • psoriatic skin lesions
  5. Reactive arthritis (eg, Reiter disease)
    • urogenital tract infection
  6. Arthritis associated with inflammatory bowel disease (eg, Crohn disease, ulcerative colitis)

Location: predominantly axial skeleton (sacroiliac joints frequently first involved)

Site: vertebra, intervertebral disk, synovial joints of spine, tendon, ligamentous attachment (enthesis)

Extraaxial involvement:

Prognosis: syndesmophytes + ankylosing spondylitis with longstanding disease

Rx: NSAID, TNF (tumor necrosis factor)–α inhibitors, intensive physical therapy

DDx: rheumatoid arthritis, degenerative disk disease, diffuse idiopathic skeletal hyperostosis, pyogenic spondylodiskitis, vertebral fracture, Paget disease

Spondylitis!!navigator!!

= ROMANUS LESION (ENTHESITIS)

= inflammation of attachment of annulus fibrosus to vertebral endplate (rim of endplate)

Site: edge of endplates

  • anterior spondylitis @ anterior endplate
  • posterior spondylitis @ posterior endplate
  • marginal spondylitis = both
  • irregularities / erosions involving edges of vertebral endplates (epiphyseal ring)
  • “shiny corners” = sclerotic changes of edges of vertebral endplates during chronic phase

MR:

  • hypointense on T1WI + hyperintense on STIR ( bone marrow edema / osteitis during acute phase)
  • hyperintense on T1WI ( postinflammatory fatty bone marrow degeneration during chronic phase)

Spondylodiskitis!!navigator!!

= ANDERSON LESION = RHEUMATIC SPONDYLODISKITIS

= noninfectious inflammation of intervertebral disk by spondyloarthritis

Prevalence: 8% of radiographs in ankylosing spondylitis

Site: diskovertebral unit (= intervertebral disk and adjacent halves of superior and inferior vertebrae)

  • irregularities / erosions of central portion of vertebral endplates (during late phase)

MR:

  • T1-hypointense + STIR-hyperintense disk signals involving one / both halves of adjacent vertebral bodies (in acute edematous phase)

Dialysis-associated Spondyloarthropathy!!navigator!!

= spondyloarthropathy in patients on long-term hemodialysis of >3 years duration

Frequency: 20% of patients on long-term hemodialysis

Cause: amyloid (β2-microglobulin) deposition in synovium and intervertebral disks

Location: lower cervical spine >craniocervical junction >thoracolumbar spine

Associated with: amyloid arthropathy of hands + wrists

Site: usually multiple levels of involvement

  • frequently asymptomatic / mild pain + stiffness
  • radiculopathy + myelopathy are unusual
  • normal ESR, normal WBC count
  • elevated levels of β2-microglobulin
  • intervertebral disk space loss ± disc vacuum phenomenon
  • extensive marginated erosions of vertebral endplates and facet joints + cyst formation
  • NO / minimal osteophytosis
  • frequently subluxation + spondylolisthesis

MR:

  • mostly hypointense disk space on T2WI

DDx:

  1. Infectious spondylodiskitis (T2-hyperintense disk space, fever)
  2. Ankylosing spondylitis
  3. Degenerative disk disease (no endplate erosions, marked osteophytosis)

Outline