Do you have an X-ray (X-ray) image of a Chance fracture?

Chance Fracture: Radiographic Imaging and Diagnosis

X-ray imaging is the initial appropriate study for suspected Chance fracture, but MRI without contrast is the most definitive imaging modality for complete evaluation of these horizontal flexion-distraction spinal injuries.

What is a Chance Fracture?

Chance fractures are relatively rare spinal injuries characterized by:

• Horizontal splitting of the vertebral body and neural arches through the pedicles, typically caused by a flexion-distraction mechanism (often called "seat belt fractures") 1
• Minimal or no decrease in the anterior height of the involved vertebral body 1
• Most commonly located between the first and third lumbar vertebrae 1, 2
• Can present with varying patterns of osseous and/or ligamentous disruption 1, 3

Diagnostic Imaging Algorithm

Initial Imaging

• Plain radiographs of the affected spinal region should be obtained first for any suspected spinal fracture 4
• Standard views include anteroposterior (AP), lateral, and oblique projections 4
• These may show the horizontal fracture line extending through the vertebral body, pedicles, and posterior elements 1

When Initial Radiographs Are Negative or Equivocal

• MRI without IV contrast is the preferred next imaging study for suspected spinal fractures with negative radiographs 4
• MRI demonstrates stress abnormalities as early as bone scintigraphy but with greater specificity 4
• MRI can detect both osseous fractures and associated soft tissue injuries such as ligamentous disruption or spinal cord injury 4

Alternative Secondary Imaging Options

• CT without IV contrast may be used when MRI is contraindicated or unavailable 4

  • CT provides excellent detail of bone cortex and trabeculae 4
  • CT has shorter acquisition times compared to MRI and may be easier to perform in patients who are immobilized 4
  • CT is particularly useful for surgical planning in complex fractures 4

• Bone scan with SPECT may be considered if MRI and CT are not available 4

  • Less specific than MRI or CT but has high sensitivity for fracture detection 4

Special Considerations

Chance Fractures in Patients with Ankylosing Spondylitis

• Patients with ankylosing spondylitis are at higher risk for spinal fractures after minor trauma 5
• CT and MRI are the imaging techniques of choice for definitive evaluation of suspected fractures in patients with spine ankylosis 4
• The entire spine should be imaged due to the potential for multilevel fractures 4

Stability Assessment and Treatment Planning

• Imaging should help determine fracture stability, as this guides treatment decisions 3
• Unstable variants typically require surgical stabilization 3, 6
• MRI is particularly valuable for assessing ligamentous injury, which may indicate instability requiring surgical intervention 4, 6

Common Pitfalls in Diagnosis

• Delayed or missed diagnosis is common with Chance fractures due to subtle radiographic findings 3
• Injuries to the distal forefoot are not directly addressed by standard imaging protocols like the Ottawa rules 4
• In patients with ankylosing spondylitis, fractures can occur after minor trauma and may be difficult to detect on plain radiographs 5
• Patients with neurological deficits should undergo MRI to assess for spinal cord injury, regardless of radiographic findings 4

Follow-up Imaging

• For confirmed fractures requiring follow-up, MRI without IV contrast is the most appropriate study to evaluate healing and potential complications 4
• CT without IV contrast may provide complementary information to MRI for assessing bony healing 4

Remember that early and accurate diagnosis of Chance fractures is crucial for appropriate treatment planning and prevention of chronic instability and neurological complications 2.