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Information

 Differential Diagnosis of Skull and Spine Disorders

Loss of Disk Space  !!navigator!!

  1. Degenerative disk disease
  2. Neuropathic osteoarthropathy
  3. Dialysis spondyloarthropathy with amyloidosis
  4. Ochronosis
  5. Ankylosing spondylitis with pseudarthrosis
  6. Sarcoidosis

Spinal Vacuum Phenomena  !!navigator!!

Pathophysiology:

= gaslike density due to

  1. acute / true vacuum phenomenon ← rapid increase in volume of joint space
    • acute protraction of shoulder in children
  2. subacute / chronic vacuum phenomenon
    • common in degenerative disk of spine

Cause: reduction of barometric pressure up to 1/20th of atmosphere

Location: joint under traction, spine

  1. nucleus pulposus Osteochondrosis
  2. annulus fibrosus Spondylosis deformans
  3. disk within vertebral body Cartilaginous node
  4. disk within spinal canal Intraspinal disk herniation
  5. apophyseal facet joint Osteoarthritis ± ~listhesis
  6. vertebral body Ischemic necrosis

Vacuum Phenomenon in Intervertebral Disk Space

= liberation of nitrogen gas from surrounding tissues into clefts with an abnormal nucleus or annulus attachment

Composition: N2 (90-92%) + O2 + CO2 + traces of other gases

Prevalence: in 1–3% of all spinal radiographs; in up to 20% of plain radiographs; in up to 50% of spinal CT in patients >age 40

Cause:

  1. Primary / secondary degeneration of nucleus pulposus
  2. Intraosseous herniation of disk (= Schmorl node)
  3. Spondylosis deformans (gas in annulus fibrosus)
  4. Adjacent vertebral metastatic disease with vertebral collapse
  5. Infection (extremely rare)
  • accentuated on supine X-ray during spine extension
  • obscured on upright radiograph during spine flexion

Site:

  1. marginal = traumatic / degenerative crack in peripheral fibers of annulus fibrosus
    • spondylosis deformans = associated with marginal single anterior osteophyte
  2. central = intradiskal cleft due to
    • primary disk degeneration
    • secondary ← injury, interference with nutrition (CPPD, alkaptonuria, trauma, Scheuermann disease, osteoporotic vertebral collapse)

Intravertebral Gas

Cause:

  1. Schmorl node = accumulation of gas from fissuring intravertebral disk
    • rounded intravertebral gas with sclerotic rim
  2. Limbus vertebrae
    • intradiskal gas extends into vertebral cleft beneath superior / inferior ring apophysis
  3. Pneumatocyst
    Incidence: 9% (on CT)
    location: iliac bone, sacrum, humeral head, clavicle
    • asymptomatic
    • cystlike lesion of gas attenuation ± sclerotic rim ± communication with adjacent joint
    • erosive defect in osteocartilaginous endplates → direct extension of gas into vertebra
  4. Intravertebral vacuum cleft
  5. Intraspinal gaseous cyst
    1. gas-containing intraspinal disk herniation
    2. gas expulsion through rent in annulus fibrosus

Intervertebral Disk Calcification  !!navigator!!

mnemonic: A DISC SO WHITE

  • Amyloidosis, Acromegaly
  • Degenerative disk disease
  • Infection
  • Spinal fusion
  • CPPD
  • Spondylitis ankylosing
  • Ochronosis
  • Wilson disease
  • Hemochromatosis, Hyperparathyroidism, Homocystinuria
  • Idiopathic skeletal hyperostosis
  • Traumatic
  • Etceteras: Gout and other causes of chondrocalcinosis

Intervertebral Disk Ossification  !!navigator!!

Associated with: fusion of vertebral bodies

  1. Ankylosing spondylitis
  2. Ochronosis
  3. Sequelae of trauma
  4. Sequelae of disk-space infection
  5. Degenerative disk disease

 Outline