In reading this report on how ERs should assess for neck injuries, it seems as if they may finally be considering doing exactly what doctors of chiropractic have been doing for years.

Neck Injury Screens Not Equivalent

 

By Crystal Phend, Senior Staff Writer, MedPage Today

Published: October 11, 2012

Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

 

 

There's a better way to screen for cervical spine injury in the emergency department, a systematic review comparing two decision rules showed.

The Canadian C-spine rule had better sensitivity and specificity for clinically important cases than the NEXUS (National Emergency X-Radiography Utilization Study) criteria, Zoe A. Michaleff, BAppSc, of the George Institute for Global Health at the University of Sydney, Australia, and colleagues reported online in CMAJ.

Both methods use patient history, physical exam characteristics, and simple diagnostic tests to determine the probability of fracture, dislocation, or ligament instability that can lead to spinal cord injury or death if missed.

Screening helps reduce the number of unnecessary referrals for imaging, cutting down on costs, radiation exposure, and psychological stress for the patient, they noted.

Many international guidelines recommend using clinical decision rules to assess the need for imaging cervical spine injuries after car accidents and other blunt trauma but without consensus on which to use.

For a comparison, the review included 15 cohort studies of patients with blunt trauma looking at a differential diagnosis of clinically important cervical spine injury detectable by diagnostic imaging.

Eight of the studies used NEXUS criteria only, which recommends diagnostic imaging for patients with neck trauma unless they meet all of the following:

• No tenderness in the posterior midline cervical spine
• No evidence of intoxication
• No focal neurologic deficit
• No painful distracting injuries
• Normal alertness with a score of 15 or better on the Glasgow Coma Scale

Six of the studies used only the Canadian C-spine rule, which uses the following criteria to send alert patients to radiography:

• Any high-risk factor, including age 65 or older, a dangerous mechanism of trauma (such a high-speed crash or fall from more than 3 ft. elevation), or paresthesias in extremities
• Absence of a low-risk factor that allows for safe assessment of range of motion (such as being ambulatory at any point, delayed onset of neck pain, or a simple rear-end car crash)
• Inability to rotate the neck 45° to the left and right

Both tests were highly sensitive with ranges from 0.83 to 1.0 for NEXUS and 0.90 to 1.0 for the Canadian C-spine rule. False negative rates were low at 1.0% or less across all studies.

These rates suggested "that a negative test result is highly informative in excluding a clinically important cervical spine injury and, therefore, the need for radiographic examination," Michaleff's group explained.

Both also showed similar potential to reduce imaging rates, by an average 31% with NEXUS and 42% with the Canadian criteria, without missing a clinically important cervical spine injury.

"However, the lower specificity and false-positive results indicate that many people will continue to undergo unnecessary imaging," the researchers noted.

Specificity ranged from 0.13 to 0.46 with NEXUS criteria and 0.01 to 0.77 with the Canadian C-spine rule
.
Only one study directly compared the two screening tools, and it gave the edge to the Canadian C-spine rule for diagnostic accuracy in terms of sensitivity, specificity, likelihood ratios, and reduction in unnecessary imaging.

The researchers cautioned about the modest methodologic quality of the studies, inability to pool data for comparison, and within-trial variations in how the rules were interpreted and applied.

"Future studies of diagnostic test accuracy need to ensure that rigorous methodologic procedures are followed to reduce bias" and to test use outside of the emergency department and in pediatric and older populations, they noted.

The researchers reported having no conflicts of interest to declare.

Primary source: CMAJ
Source reference:
Michaleff ZA, et al "Accuracy of the Canadian C-spine rule and NEXUS to screen for clinically important cervical spine injury in patients following blunt trauma: a systematic review" CMAJ 2012; DOI: 10.1503 /cmaj.120675.