Author:  Dr. Keya Patel


Each year, more than 1 million patients are treated in the emergency department for blunt trauma and potential C-spine injury. Cervical CT remains the mainstay of imaging in assessing for injury. Here, we review the Canadian C-spine Rule in determining the need for advanced imaging such as CT.

Study Question

Can a clinical decision rule be used to assess for cervical spine injury in alert and stable trauma patients?

Study Design

  • Prospective cohort study of blunt trauma patients from 10 Canadian EDs
  • 20 standardized clinical findings before radiographs, 5 demographic variables obtained in addition by RNs from hospital records
  • Flex/Ex views and CT C-spine ordered at discretion of treating physician
  • Subset of patients were also assessed by second EM physician
  • Rule was derived using κ coefficient, logistic regression analysis, χ2 recursive partitioning techniques 
  • Primary Outcome: Clinically important C-spine injury (fracture, dislocation or ligamentous instability on imaging) which requires stabilization or specialized follow-up
    • Not clinically important:
      • isolated avulsion fracture of osteophyte
      • isolated transverse process fracture of involving facet joint
      • isolated spinous process fracture not involving lamina
      • simple compression fracture (<25% of vertebral body height)

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  • 12,782 eligible patients from October 1996 to April 1999
  • 3,281 eligible patients examined but not enrolled by the treating physicians
  • 577 eligible patients were also not included in the final study group because they did not undergo C-spine radiography and could not be reached for the proxy outcome measure
  • OVERALL: 8,924 patients were enrolled and assessed for primary outcome
    • PRIMARY OUTCOME: 151 patients (1.7%) found to have clinically significant c-spine injury

Deriving the Canadian C-Spine Rule from Odds Ratios

  1. Table 4 (below) from the study shows the specific set of variables that were used to derive the Canadian C-spine Rule based on the OR


    Table 4

  2. Dangerous mechanism, Age >65 and paresthesia all have an OR >1, thus a significant correlation to C-spine injury, and are the first set of variables of the Canadian C-spine Rule
    Old 1    Old 2
  3. Found to have 100% Sensitivity, 42.5% Specificity


Further Discussion

  • Strengths
    • Methodological standards strictly followed
    • Primary outcome clearly defined
    • Blinded study
    • Reproducibility of predictor findings assessed by having subset of patients examined by 2 physicians
    • Wide spectrum characteristics of patients – increases generalizability
  • Weaknesses
    • Is definition of primary outcome (clinically important c-spine injury) accepted outside of Canada?
    • Not all study participants underwent c-spine radiography
  • Compared to NEXUS
    • Criteria:
      • absence of midline tenderness
      • normal level of alertness
      • no evidence of intoxication
      • no abnormal neurological findings
      • no painful distracting injuries
    • Outcomes
      • N = 34,069 patients evaluated with imaging of cervical spine
      • 818 (2.4%) had radiographically documented cervical-spine injury 
      • 578 (1.7%) had clinically significant cervical-spine injury
      • 99% sensitivity and 12.9% specificity


Stiell, Ian et al. “The Canadian C-spine Rule for Radiography in Alert and Stable Trauma Patients”. JAMA. 2001. 286(15):1841-1848.

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