Canadian Cervical Spine Rules: Moving North a Better Option, Eh?

Main Points:

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1. The final Canadian C-spine Rule comprises three questions:

A.) Is there a high-risk factor that mandates radiography such as: age≥65, dangerous mechanism, or paresthesias in extremities?

B.) Is there any low-risk factor that allows safe assessment of range of motion such as: simple rear end MVC, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness?

C.) Is the patient able to actively rotate neck 45° to the left and right?

 

  1. The Canadian C-Spine Rule was tested on a convenience sample of 8,924 alert and stable trauma patients in 10 Canadian emergency departments with 151 cases of clinically significant C-spine injury and proved to have a sensitivity of 100% (95% CI: 98-100%) and a specificity of 42.5% (95% CI: 40-44%).

 

Background:

Less than three percent of trauma series yield a positive result.

According to the data compiled by the researchers in the Canadian CT Head and C-Spine Study the use of C-spine radiography is quite variable among emergency physician providers based on local culture and the overall cost of C-spine radiography is in the multi-millions. Their research demonstrated that less than three percent of trauma series yield a positive result.
The overall goal of the collaborative was to help standardize clinical practice while simultaneously reducing healthcare expenditure. This effort was undertaken at the same time as the NEXUS criteria were being established, however NEXUS beat the CCR to publication by approximately one year. These researchers repeatedly voice concerns over the low specificity of the NEXUS criteria, 12%, throughout their study. They are also critical of the vague nature of “presence of intoxication” as well as “distracting painful injuries” within the NEXUS criteria. The CCR included adult patients older than 16 years of age who presented to 10 large Canadian community and university hospitals after sustaining acute blunt trauma to the head or neck. These patients were defined as alert and stable by having a GCS score of 15 and SBP >90mm Hg and respiratory rate between 10-24/min. The primary outcome measure was “clinically important cervical spine injury defined as any fracture, dislocation, or ligamentous instability demonstrated by diagnostic imaging.”

Details:

This trial was a prospective cohort study that included adult trauma patients 16 years and older presenting to the 10 study hospitals. It excluded anyone deemed to be unstable either through vital sign abnormality or mental status deficit notable for a GCS <15. Patients needed to have a significant injury within 48 hours of presentation and could not have conditions that affect the vertebral system or be pregnant. Radiography in this study consisted of a minimum of three views though physician discretion allowed for the addition of flexion-extension views and CT if deemed necessary. The study did not enroll patients consecutively because the authors report “…not all patients with blunt trauma routinely undergo C-spine radiography at the Canadian study sites [therefore] we could not ethically mandate universal radiography for all eligible patients.” The patients for whom no radiography studies were ordered were followed by a validated 14-day telephone interview. Of the total 8,924 patients cervical spine radiography was performed in 68.9% and CT in 4.9% while 31.1% of cases were followed up by telephone. A total of 151 cases of clinically important cervical spine injury was noted as well as an additional 28 cases of unimportant injuries such as: spinous or transverse process fracture, osteophyte avulsion, vertebral compression <25% of the body height. This trial helped to highlight that particular mechanisms of injury carry increased risk of important injury.

Level of Evidence:

Based on the ACEP grading scheme for diagnostic questions the CCR trial receives a class of evidence rating of 1.

Relevant articles:

Ian Stiell and his colleagues are relentless in their pursuit of helping to standardize patient care and reduce reportedly unnecessary cervical spine imaging. This group of researchers embarked on a head to head comparison of NEXUS and CCR by studying a prospectively enrolled cohort of 8,223 patients with almost 400 physicians applying both the NEXUS criteria and CCR prior to radiography. 169 of these patients were demonstrated to have a clinically significant injury which represents an equal degree of disease burden as seen in the parent studies. The resulting data demonstrated that the CCR had a higher sensitivity and much greater specificity than the NEXUS criteria. Ultimately this would have resulted in 1 missed patient for CCR, but 16 for the NEXUS criteria in this cohort of patients.

Source Articles:

 

  1. Stiell, G. Wells, K. Vandemheen, et al. “The Canadian C-Spine Rule for Radiography in Alert and Stable Trauma Patients.” JAMA, October 2001; 288(15): 1841-48
  2. Stiell, G. Wells, D. McKnight, et al. “Canadian C-Spine Rule Study for Alert and Stable Trauma Patients: I. Background and Rationale.” CJEM, March 2002; 4(2): 84-90
  3. Stiell, G. Wells, D. McKnight, et al. “Canadian C-Spine Rule Study for Alert and Stable Trauma Patients: II Study Objectives and Methodology.” CJEM, May 2002; 4(2): 185-93
  4. Stiell, C. Clement. D. McKnight, et al. “The Canadian C-Spine Rule Versus the NEXUS Low-Risk Criteria in Patients with Trauma.” NEJM, December 2003; 349(26): 2510-18

Anatoly Kazakin MD

3 thoughts on “Canadian Cervical Spine Rules: Moving North a Better Option, Eh?

  1. Question about the Specificity noted in this study and the NEXUS study:
    When I look at these rules to clear a c-spine, I think of the sensitivity of such studies as what is important. Why do the Canadian authors comment on the Specificity as compared to NEXUS and how does this correlate to how I use the rule if it is to “rule out” significant injury?

  2. Ed,
    The Canadians care a lot about cost reduction and therefore the specificity of the clinical decision rule is also key for them.

  3. I think it’s mind blowing that only 4.9% of their patient’s got a CT C-spine. I can’t remember the last time I ordered plain films of the neck…

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