A retrospective study of patients with minor head injury to compare the Canadian CT Head Rule and the New Orleans Criteria

Objective: To compare the performance of the Canadian CT Head Rule (CCHR) and the New Orleans Criteria (NOC) in minor head injury patients. Method: This retrospective cohort study collected data and CT head reports of all minor head injury patients from 1 January 2008 to 31 December 2010. We compared the sensitivity, specificity, positive and negative predictive values of both rules in predicting clinically important brain injury on CT and the need of neurosurgical intervention. Results: We reviewed 474 patients with minor head injury. Seventy seven patients had clinically important brain injury and 11 underwent neurosurgical intervention. The sensitivity of the CCHR and NOC in predicting clinically important brain injury were 80% (95% confidence interval [CI] 70-88%) and 92% (95% CI 86-98%), respectively; and the specificity of the CCHR and NOC were 39% (95% CI 33-44%) and 17% (95% CI 13-21%), respectively. The sensitivity of the CCHR and NOC in predicting the need of neurosurgical intervention were 80% (95% CI 55-100%) and 100% (95% CI 100-100%), respectively; and the specificity of the CCHR and NOC were 36% (95% CI 31-41%) and 15% (95% CI 12-19%), respectively. The negative predictive values (NPV) of the CCHR and NOC for clinically important brain injury were 88% (95%CI 83-94%) and 91% (95%CI 84-98%); and for the need of neurosurgical intervention were 99 %( 95% CI 96-100%) and 100% (95% CI 100-100%). Amongst those missed cases, 88% in the CCHR group and 83% in the NOC group reported loss of consciousness. Conclusions: The NOC is more sensitive but less specific than the CCHR in predicting both outcomes. Both rules have excellent NPV to rule out the need of neurosurgical intervention.