NEXUS and the Canadian C-Spine Rule: How Clinicians Decide Who Gets Neck Imaging
NEXUS and the Canadian C-Spine Rule are clinical decision rules that tell an emergency clinician whether an alert, stable trauma patient needs neck imaging. Both were built to find clinically important cervical spine injuries, which in practice means fractures, dislocations, and ligament injuries that need treatment. A patient who passes either rule has a very low chance of that kind of injury. Passing does not mean the neck is uninjured, and that distinction comes up constantly in car accident cases I see in Charlotte.
The NEXUS Low-Risk Criteria
NEXUS, the National Emergency X-Radiography Utilization Study, was tested in 34,069 blunt trauma patients at 21 centers in the United States. A patient is low risk only if all five criteria are met: no midline cervical tenderness, no focal neurologic deficit, normal alertness, no intoxication, and no painful distracting injury. The rule missed 8 of 818 patients with cervical spine injury, for a sensitivity of 99.0%. Specificity was 12.9%, and imaging could have been avoided in 12.6% of patients (Hoffman, N Engl J Med 2000).
The rule is easy to apply and conservative. Its weakness is that it sends most trauma patients to imaging anyway.
The Canadian C-Spine Rule
The Canadian rule was derived in 8,924 alert adults with stable vital signs and a Glasgow Coma Scale score of 15 at ten Canadian emergency departments. It asks three questions in order (Stiell, JAMA 2001).
First, is a high-risk factor present? These are age 65 or older, numbness or tingling in the arms or legs, and a dangerous mechanism. Dangerous mechanisms are defined as a fall from more than 3 feet or five stairs, an axial load to the head such as a diving injury, a motor vehicle collision at more than 100 km/h, a collision with rollover or ejection, a motorized recreational vehicle injury, or a bicycle collision (Stiell, CMAJ 2010). Any one of these means imaging.
Second, is a low-risk factor present that allows a safe range of motion check? These include a simple rear-end collision, sitting in the emergency department, walking at any time since the injury, delayed onset of neck pain, and no midline tenderness. A rear-end collision is not simple if the patient was pushed into oncoming traffic, was hit by a bus, a large truck, or a high-speed vehicle, or rolled over. Delayed onset means the neck pain did not start immediately after the collision (Stiell, CMAJ 2010).
Third, can the patient actively rotate the neck 45 degrees to the left and right? If yes, no imaging is needed.
In derivation, the rule had 100% sensitivity and 42.5% specificity for 151 clinically important injuries (Stiell, JAMA 2001).
How the Two Rules Compare
A prospective study across nine Canadian emergency departments applied both rules to 8,283 patients, 169 of whom had clinically important injuries. The Canadian rule was more sensitive, 99.4% versus 90.7%, and more specific, 45.1% versus 36.8%. It would have missed 1 injured patient, and NEXUS would have missed 16. The Canadian rule also had a practical problem: physicians failed to check range of motion, as the algorithm requires, in 10.2% of patients (Stiell, N Engl J Med 2003).
The rule holds up outside physician hands. When 191 triage nurses applied it to 3,633 patients after two hours of training, the investigators' interpretation had 100% sensitivity. The nurses' own classifications had 90.2% sensitivity, with four early misses despite clear high-risk factors and no further misses after retraining. Interobserver agreement was a kappa of 0.78 (Stiell, CMAJ 2010).
What a Negative Rule Does Not Mean
Both rules answer one question: does this patient need imaging now to look for an injury that needs urgent treatment? They were not designed to detect subfailure ligament injuries, the stretched ligaments that can allow excessive motion without a fracture. A patient in a simple rear-end collision who walks into the emergency department and can turn their head is low risk under the Canadian rule. That classification is about fracture risk and imaging need. It says nothing either way about whether a ligament was strained.
For the attorneys I work with in Charlotte, this is the point to understand when records read "C-spine cleared clinically." That phrase means a decision rule was applied and imaging was not indicated. It is not a finding that the soft tissues of the neck are normal.
For an example of how post-collision imaging findings and outcomes are documented in the peer-reviewed literature, read Dr. Justin Dick's published case report on refractory lumbar pain following a motor vehicle accident in a geriatric patient.
Frequently Asked Questions
What are the NEXUS criteria?
NEXUS clears a trauma patient from neck imaging only if all five are met: no midline cervical tenderness, no focal neurologic deficit, normal alertness, no intoxication, and no painful distracting injury. In 34,069 patients it had 99.0% sensitivity (Hoffman, N Engl J Med 2000).
What counts as a dangerous mechanism in the Canadian C-Spine Rule?
A fall from more than 3 feet or five stairs, an axial load to the head such as diving, a motor vehicle collision at more than 100 km/h or with rollover or ejection, a motorized recreational vehicle injury, or a bicycle collision (Stiell, CMAJ 2010).
Is the Canadian C-Spine Rule better than NEXUS?
In a direct comparison of 8,283 patients, the Canadian rule was more sensitive, 99.4% versus 90.7%, and more specific, 45.1% versus 36.8% (Stiell, N Engl J Med 2003).
Does a simple rear-end collision mean I was not injured?
No. Under the Canadian C-Spine Rule, a simple rear-end collision is a low-risk factor for fracture and imaging need. The rule was not designed to detect stretched ligaments and says nothing about soft tissue injury.
What does C-spine cleared clinically mean in my records?
It means a decision rule such as NEXUS or the Canadian C-Spine Rule was applied and imaging was not indicated. Dr. Justin Dick explains to patients and attorneys in Charlotte, NC that it is not a finding that the neck's soft tissues are normal.
Where can I get my neck evaluated after a car accident in Charlotte, NC?
Dr. Justin Dick, DC, CNMT, ARRT(N)(CT), evaluates neck injuries after car accidents at Clear Life Scoliosis and Chiropractic Center, 8814 Rachel Freeman Way, Suite 103, Charlotte, NC 28278, phone 980-368-0766. Personal injury patients are treated on a lien basis, with no out-of-pocket payment at the time of care.
Sources and Evidence Tiers
- Hoffman JR, Mower WR, Wolfson AB, Todd KH, Zucker MI. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. N Engl J Med. 2000;343(2):94-99. PMID 10891516. LinkEvidence tier: Prospective multicenter cohort
- Stiell IG, Wells GA, Vandemheen KL, et al. The Canadian C-spine rule for radiography in alert and stable trauma patients. JAMA. 2001;286(15):1841-1848. PMID 11597285. LinkEvidence tier: Prospective derivation cohort
- Stiell IG, Clement CM, McKnight RD, et al. The Canadian C-spine rule versus the NEXUS low-risk criteria in patients with trauma. N Engl J Med. 2003;349(26):2510-2518. PMID 14695411. LinkEvidence tier: Prospective comparative cohort
- Stiell IG, Clement CM, O'Connor A, et al. Multicentre prospective validation of use of the Canadian C-Spine Rule by triage nurses in the emergency department. CMAJ. 2010;182(11):1173-1179. PMID 20457772. LinkEvidence tier: Prospective multicenter validation cohort
About the author. Dr. Justin M. Dick, DC, is the owner and treating clinician at Clear Life Scoliosis and Chiropractic Center in Charlotte, NC. He holds dual imaging credentials as a Certified Nuclear Medicine Technologist (CNMT) and as an ARRT-registered technologist in nuclear medicine and CT, ARRT(N)(CT). He is a Senior Fellow of the CLEAR Institute, holds the ISICO World Masters credential, is a SOSORT provisional member, and is a certified DOT medical examiner on the FMCSA National Registry. He has multiple peer-reviewed publications indexed in PubMed and serves as adjunct faculty at Life, Sherman, and Palmer chiropractic colleges.
Service Area
Clear Life Scoliosis and Chiropractic Center sees personal injury and spinal imaging patients from Charlotte NC, Huntersville NC, Ballantyne NC, Matthews NC, Concord NC, Mooresville NC, Rock Hill SC, and Fort Mill SC.
Related Pages
- Personal injury and car accident spinal care in Charlotte
- Dr. Justin Dick's research
- Case report: refractory lumbar pain after a motor vehicle accident
- Research and evidence at Clear Life
- Questions and answers
- Our team
- Press
- Book your evaluation
- Contact Clear Life
Clear Life Scoliosis and Chiropractic Center
8814 Rachel Freeman Way, Suite 103
Charlotte, NC 28278
Phone: 980-368-0766
Email: office@clearlifescoliosis.com
Book online
Justin Dick
Contact Me
