What is the recommended imaging protocol for a patient with a suspected C1 (cervical spine) fracture with the mouth open?

Imaging Protocol for C1 Fracture with Open Mouth View

CT of the cervical spine without IV contrast is the gold standard and recommended first-line imaging for suspected C1 fractures, with open-mouth odontoid views only used in specific circumstances when CT is unavailable. 1, 2

Initial Imaging Approach

Primary Imaging

• CT Cervical Spine without IV contrast
  • Considered gold standard for identifying cervical spine fractures with 97% detection rate
  • Significantly outperforms radiographs (which only detect about 1/3 of fractures visible on CT)
  • Provides excellent visualization of C1 (atlas) fracture patterns and displacement
  • Should be obtained promptly when C1 fracture is suspected 1, 2

Secondary Imaging (if needed)

• MRI Cervical Spine without IV contrast
  • Indicated when:
    • Neurologic deficits are present
    • Soft tissue injury is suspected
    • CT findings are equivocal
    • Patient remains unexaminable
  • Superior for detecting soft tissue injuries (ligaments, spinal cord, nerve roots)
  • Can identify injuries missed on CT in 5-24% of cases 1, 2, 3

When Radiographs May Be Used

• Open-mouth odontoid view should only be used when:

  • CT is unavailable
  • As part of a three-view series (AP, lateral, and open-mouth)
  • For follow-up of known fractures
  • As a problem-solving tool in case of motion on cervical spine CT 1

• Complete radiographic series should include:

  • Anteroposterior view
  • Lateral view (including cervicothoracic junction)
  • Open-mouth odontoid view
  • Additional "swimmer's lateral view" if cervicothoracic junction not visible 1

Important Considerations

• CT has limitations in detecting transversely oriented fractures of the dens and facet joints 4
• Isolated C1 fractures represent 7% of cervical spine fractures, but 44% of C1 fractures occur in combination with C2 fractures 5
• Concomitant facial trauma increases risk of cervical spine injury (7-11.3% of facial fracture patients have cervical spine injuries) 1

Common Pitfalls to Avoid

• Relying solely on radiographs can miss approximately 67% of fractures visible on CT 1, 2
• Flexion-extension views have limited utility and are not recommended in the initial evaluation 1
• Failing to obtain MRI when neurologic symptoms are present despite negative CT 2
• Not evaluating the cervicothoracic junction, which can result in missed injuries 1

In cases with high clinical suspicion but negative initial imaging, additional CT slices covering C1-C3 should be considered, as studies have shown this approach can detect fractures not visible on plain films 6.