Clinical Question: Which clinical decision rule is better at recognizing cervical spine injury, the Canadian C-spine (cervical-spine) rule or the National Emergency X-Radiography Utilization Study (NEXUS) low-risk criteria rule?
Setting: Emergency department
Study Design: Decision rule (validation)
Synopsis: Two clinical decision rules may be used to help identify patients at risk for significant cervical spine injury and to guide the use of cervical spine films—the Canadian C-spine rule and the NEXUS rule. Only the latter has been validated prospectively. This study, conducted by the group that developed the Canadian C-spine rule, compared the performance of these two decision rules in a prospective study.
A total of 8,283 adults with acute trauma to the head or neck were identified; they were in stable condition, had visible injury above the clavicles, had normal mental status and vital signs, and were not ambulatory. Persons with penetrating neck trauma, acute paralysis, paralysis, or known vertebral disease were excluded. C-spine films were ordered at the discretion of the 394 treating physicians, who were instructed not to use either decision rule to guide their care. Patients in whom radiography was not performed were contacted 14 days later and recalled for radiography if they had more than mild pain or mild neck-movement restriction, were using a collar, or had not resumed usual activities.
A total of 169 patients (2 percent) had a clinically important cervical spine injury, defined as any fracture, disclocation, or ligamentous instability. The average age of the participants was 37.6 years, 52 percent were men, and 67 percent had been in a motor vehicle crash. Range of motion was not evaluated in about 10 percent of patients, who then were labeled “indeterminate” and were excluded from analysis of the accuracy of the Canadian C-spine rule. Radiography was performed in almost all of these patients; the authors speculate, probably correctly, that the physicians were uncomfortable assessing the range of motion in these patients before radiography. These 845 patients, including seven with serious injuries, were excluded from the trial.
Of the remaining 7,438 patients with 162 clinically important injuries, the Canadian C-spine rule detected 161 of 162 clinically important injuries and the NEXUS rule detected 147 of 162 (sensitivity = 99.4 percent versus 90.7 percent). The Canadian C-spine rule also was somewhat more specific than the NEXUS rule (45.1 percent versus 36.8 percent). The Canadian C-spine rule had a higher inter-rater reliability than the NEXUS rule: 0.63 versus 0.47. Physicians were slightly more uncomfortable when applying the Canadian C-spine rule (8.0 percent versus 7.1 percent using the NEXUS rule were uncomfortable or very uncomfortable; P = .03), and they also were somewhat more likely to misinterpret the results (5.0 percent versus 2.9 percent using NEXUS). Fewer patients required radiography based on the use of the Canadian C-spine rule than the NEXUS rule (56 percent versus 67 percent), reducing cost and length of stay in the emergency department.
Bottom Line: Results of this study show that the Canadian C-spine rule is more sensitive and specific than the NEXUS rule. With proper training, the Canadian C-spine rule can be used safely in the emergency department to identify adults who require cervical spine radiography. Application of the rule will reduce the number of radiographs and shorten the length of stay of these patients in the emergency department. (Level of Evidence: 1a)