When is a CT (Computed Tomography) scan indicated for the cervical spine after a Motor Vehicle Collision (MVC)?

CT Indications for Cervical Spine After Motor Vehicle Collision

CT imaging of the cervical spine is indicated after a motor vehicle collision when patients meet any of the NEXUS criteria or Canadian C-Spine Rules, as these clinical decision tools have high sensitivity for detecting clinically significant cervical spine injuries. 1

NEXUS Criteria for Cervical Spine Imaging

CT cervical spine imaging is indicated if ANY of the following are present:

• Altered level of consciousness (GCS <15) 1
• Presence of neck pain or tenderness on palpation 1
• Presence of focal neurologic deficit 1
• Evidence of intoxication 1
• Presence of a painful distracting injury 1

Canadian C-Spine Rules

CT cervical spine imaging is indicated if ANY of the following are present:

• Age ≥65 years (even if other criteria are negative) 1
• Dangerous mechanism of injury (fall from height, rollover MVC, ejection from vehicle, high-speed collision) 1
• Paresthesias in extremities 1, 2
• Inability to actively rotate neck 45° to left and right 1, 2

Special Considerations

• Age >65 years: Older adults should have a lower threshold for imaging as NEXUS criteria have reduced sensitivity (66-89%) in this population 1
• Obtunded patients: Always obtain CT imaging as clinical assessment is unreliable 1
• High-risk mechanisms: CT imaging is warranted regardless of symptoms when the mechanism involves high-energy transfer 1, 3
• Neurological symptoms: When present, CT should be performed even with minimal neck pain 1, 4

Imaging Modality Selection

• CT scan is the first-line imaging modality for suspected cervical spine injury after MVC due to its superior sensitivity (88.6-100%) compared to plain radiographs (36.4%) 4, 5
• Plain radiographs are inadequate for ruling out cervical spine injuries in trauma patients, identifying only about one-third of fractures visible on CT 1, 6
• MRI should be considered as a follow-up study when:
  • Neurological deficits are present despite negative CT 1, 4
  • Ligamentous injury is suspected 1
  • Patient remains symptomatic with neck pain despite negative CT 1, 4

Common Pitfalls to Avoid

• Relying solely on plain radiographs: Even with multiple views, plain films miss significant injuries that CT can detect 1, 6
• Clearing the cervical spine in obtunded patients without imaging: Clinical assessment is unreliable in this population 1
• Ignoring persistent neck pain: Patients with persistent symptoms despite negative CT may have ligamentous injuries that require MRI for detection 1
• Overlooking non-contiguous injuries: When one spinal injury is found, approximately 20% of patients will have injuries at other levels of the spine 1

Algorithm for Decision Making

1. Assess for NEXUS criteria or Canadian C-Spine Rules 1
2. If ANY criteria are positive → Obtain CT cervical spine without contrast 1
3. If CT positive → Consult spine service and consider MRI for surgical planning 1
4. If CT negative but neurological symptoms present → Obtain MRI cervical spine 1, 4
5. If CT negative in obtunded patient → MRI is recommended to evaluate for ligamentous injury 1

CT cervical spine imaging provides the optimal balance of sensitivity and specificity for detecting clinically significant injuries after motor vehicle collisions when clinical decision rules indicate the need for imaging 1, 5.