What is the difference between the Canadian C-spine (Cervical Spine) rule and the NEXUS (National Emergency X-Radiography Utilization Study) criteria?

Canadian C-Spine Rule vs. NEXUS: Comparison and Clinical Application

The Canadian C-Spine Rule (CCR) is superior to NEXUS for cervical spine injury assessment, with higher sensitivity (98.7% vs 89.9%) and better diagnostic accuracy for detecting clinically important cervical spine injuries. 1

Key Differences Between CCR and NEXUS

Canadian C-Spine Rule (CCR)

• Structure: More complex algorithm with high-risk and low-risk factors
• Sensitivity: 98.7% (95% CI: 95.7-99.6%) 1
• Specificity: 16.7% (higher than NEXUS in some studies) 1
• Diagnostic Odds Ratio: 14.65 (superior to NEXUS) 1
• Imaging Reduction: Can reduce unnecessary radiography by approximately 42% 2

NEXUS Criteria

• Structure: Simple 5-factor assessment
• Sensitivity: 89.9% (95% CI: 84.5-93.6%) 1
• Specificity: 39.8% 1
• Diagnostic Odds Ratio: 5.89 1
• Imaging Reduction: Would reduce cervical spine radiography rates by only about 6.1% 3

Canadian C-Spine Rule Algorithm

Step 1: Assess for High-Risk Factors

If ANY of these are present, imaging is required:

• Age ≥65 years
• Dangerous mechanism of injury:
  • Fall from >3 feet/5 stairs
  • Axial load to head
  • High-speed MVC, rollover, or ejection
  • Motorized recreational vehicle accident
  • Bicycle collision
• Paresthesias in extremities 2

Step 2: Assess for Low-Risk Factors

If NO high-risk factors AND at least ONE of these factors is present:

• Simple rear-end MVC
• Sitting position in ED
• Ambulatory at any time since injury
• Delayed onset of neck pain
• Absence of midline cervical tenderness 2

Step 3: Range of Motion Assessment

• If patient meets low-risk criteria, ask them to actively rotate neck 45° left and right
• If patient can do this, no imaging is needed 2

NEXUS Criteria

Imaging is NOT required if ALL five criteria are met:

1. No midline cervical tenderness
2. No focal neurological deficit
3. Normal alertness (GCS 15)
4. No intoxication
5. No painful distracting injury 4

Clinical Application and Limitations

Strengths of CCR

• Higher sensitivity (98.7% vs 89.9%) 1
• Better at identifying patients who truly need imaging
• Has been validated for use by triage nurses (kappa 0.78) 5
• More structured approach with specific criteria

Limitations of NEXUS

• Lower sensitivity than previously reported when tested in Canadian settings (92.7%) 3
• Failed to identify 11 patients with important injuries in one study, with 5 requiring significant intervention 3
• Particular caution needed in elderly patients, as significant injuries may be missed 6

Special Considerations

• Neither rule should be applied to:
  • Patients who are not alert (GCS <15)
  • Unstable patients
  • Pediatric patients (under 16 years)
  • Patients with acute paralysis 2

Imaging Recommendations

When imaging is indicated by either rule:

• CT is now preferred over plain radiographs due to significantly higher sensitivity for detecting cervical spine fractures 4, 7
• MRI should be considered when CT is negative but patient has persistent neurological symptoms, as it can reveal injuries missed by CT 7
• Plain radiography and LODOX have insufficient sensitivity (36.4% and 5.3% respectively) to rule out cervical spine injury 7

Bottom Line

CCR demonstrates superior diagnostic performance compared to NEXUS, with higher sensitivity and better ability to reduce unnecessary imaging. While both are validated clinical decision tools, the CCR should be preferred when possible due to its greater accuracy in identifying patients with clinically significant cervical spine injuries.