5 Minute Journal: Canadian C-Spine

Author:  Dr. Keya Patel

Background

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)

Outcome

• 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
     
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

Reference:

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