studies with modest methodologic quality and 1 direct comparison, the Canadian
C-spine rule appears to have better diagnostic accuracy than the National
Emergency X-Radiography Utilization Study (NEXUS) criteria when used to assess
the need for cervical spine imaging, say authors of a systematic review published in CMAJ.
Future studies need to follow rigorous methodologic procedures to ensure that
the findings are as free of bias as possible, they add.
For this review, the authors identified studies by an electronic search of
CINAHL, Embase, and MEDLINE. They included articles that reported on a cohort
of patients who experienced blunt trauma and for whom clinically important
cervical spine injury detectable by diagnostic imaging was the differential
diagnosis, evaluated the diagnostic accuracy of the Canadian C-spine rule or
NEXUS or both, and used an adequate reference standard. They assessed the
methodologic quality using the Quality Assessment of Diagnostic Accuracy
Studies criteria. They used the extracted data to calculate sensitivity,
specificity, likelihood ratios, and posttest probabilities.
Fifteen studies of modest methodologic quality were included in the review. For the Canadian
C-spine rule, sensitivity ranged from 0.90 to 1.00 and specificity ranged from
0.01 to 0.77. For NEXUS, sensitivity ranged from 0.83 to 1.00 and specificity
ranged from 0.02 to 0.46. One study directly compared the accuracy of these 2
rules using the same cohort and found that the Canadian C-spine rule had better
accuracy. For both rules, a negative test was more informative for reducing the
probability of a clinically important cervical spine injury.