Thoracic and lumbar spine trauma

Background
  • Injury to thoracic spine necessitates severe force
    • thoracic spine has enhanced stiffness secondary to articulations with the rib cage
    • When spinal cord injury occurs usually complete
    • thoracic spinal canal is narrower than in other regions, increased risk of cord injury
  • Important to evaluate for thoracic spine injuries and aortic injuries in the setting of blunt chest trauma with mediastinlal widening
  • Follows the three column model - Stable if two or more of the spinal columns are intact:
    • Anterior (anterior longitudinal ligament, annulus fibrosus, ant. half of the vertebral body)
    • Middle (posterior longitudinal ligament, posterior annulus fibrous, and post. half of vertebral body
    • Posterior (supraspinous and interspinous ligaments, ligamentum flavum, facet joint capsule)
  • Unstable if:
    • 50% loss of vertebral height
    • Kyphotic angulation around the fracture:
      • >30' for compression fracture
      • > 25' for burst fracture
    • Neurologic deficit

Classification

Compression (wedge)
  • Only unstable if posterior ligament complex ruptures (requires a rotational force)
  • Mechanism: axial loading and flexion
  • Unlikely to cause cord damage
  • Suspect instability and obtain CT if:
    • Severe compression (>50% loss of vertebral height)
    • Kyphosis >30deg
    • Rotational component to injury
    • Compression fracture at multiple sites
    • Posterior cortex abnormality

Thoracic burst fracture

Lumbar burst fracture
  • considered unstable
  • Mechanism: axial load with failure of the anterior and middle columns
  • Can cause cord damage

Chance Fracture (Flexion-distraction injuries)
  • Common mechanism: seat belt serves as axis of rotation with failure of middle and posterior columns
  • Most common at T12-L2 due to spinal curvature and mechanism
  • Pure bony injury from posterior to anterior through:
    • Spinous process
    • Pedicles
    • Vertebral body
  • Unstable
  • Seat Belt Injury: lap belt worn above the pelvic bones without a shoulder harness
  • Mechanism: minor anterior vertebral compression with failure of the middle and posterior columns
  • May be misdiagnosed as anterior compression fracture, which is usually stable
  • Intra-abdominal injuries more commonly associated than neuro deficits
  • Obtain sagittally reconstructed CT if suspect lap-belt mechanism or flexion-distraction

fracture dislocations
  • Unstable
  • Most damaging of all injuries
  • Mechanism: multiple can be compression, flexion, distraction, rotation or shearing forces causing failure of anterior, middle and posterior columns


Minor Thoracic and Lumbar Spine Fractures
  • Transverse process fracture
  • Spinous process fracture
  • Pars interarticularis fracture

Imaging
  • Indications to Image Thoracic and Lumbar Spine after Trauma
    • Mechanism
      • Gunshot, High energy trauma, Motor vehicle crash with rollover or ejection, Fall >10 ft or 3 m, Pedestrian hit by car
    • Physical Exam
      • Midline back pain, Midline focal tenderness, Evidence of spinal cord or nerve root deficit
    • Associated injuries
      • Cervical fracture, ribe fracture, aortic injuries, hollow viscus injuries
  • Plain radiographs or CT scan to evaluate for body abnormality
  • Can reformat Chest and Abdomen CT to look at thoracic, lumbar spine
  • MRI is diagnostic test of choice to evaluate patients with nerve injury
  • CT myelography alternative when MRI unavailable
  • anterior vertebral body compression fracture with extension through middle of vertebral body into posterior wall
  • Compression fracture + increased posterior interspinous spaces caused by distraction

10% of patients with a spine fracture have second fracture in a different segment

Management
    • type and screen/cross, labs including pancreatic enzymes if thoraco-lumbar location
    • consult ortho or neurosurgery (institution dependent)
    • spinal precautions
    • emergency operative repair unless medically unstable

Translational
  • Massive direct trauma to the back > failure of all 3 columns
  • Almost invariably demonstrate neuro deficits

Differential Diagnosis

Lower Back Pain

Management

LUMBAR

  • Stable Fractures - TLSO brace as directed by Neurosurg


CT IF:

  • Compression
  • Wedge
  • >50% height (rule out middle column & burst)

Disposition


See Also

References
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