NEXUS and Canadian C-Spine Rules¶

Overview¶

The NEXUS (National Emergency X-Radiography Utilization Study) criteria and the Canadian C-Spine Rule (CCR) are validated clinical decision rules designed to identify trauma patients who are at very low risk for clinically significant cervical spine injury and can be safely cleared without imaging. Both rules aim to reduce unnecessary imaging while maintaining high sensitivity for detecting injuries that require treatment.

NEXUS Criteria¶

The NEXUS criteria were developed from a prospective observational study of over 34,000 patients at 21 emergency departments across the United States. The rule states that cervical spine imaging is not required if ALL five of the following criteria are met:

1. No posterior midline cervical tenderness — assessed by palpation of the spinous processes from C1 through C7
2. No focal neurological deficit — motor or sensory deficits in any extremity
3. Normal alertness — patient is fully awake and oriented (GCS 15)
4. No intoxication — no evidence of alcohol or drug intoxication
5. No painful distracting injury — no injury elsewhere that could distract the patient from perceiving cervical pain

Performance¶

• Sensitivity: 99.6% for clinically significant cervical spine injury
• Specificity: approximately 12.9%
• Negative predictive value: 99.9%

The high sensitivity and negative predictive value mean that very few injuries are missed when all five criteria are met. However, the low specificity means that many patients who undergo imaging will not have an injury — the rule is designed to be highly inclusive to avoid missing injuries.

Canadian C-Spine Rule¶

The Canadian C-Spine Rule was developed from a prospective cohort study of over 8,000 patients at 10 Canadian emergency departments. It uses a three-step algorithm:

Step 1 — High-Risk Factors (Mandating Imaging)¶

Imaging is required if ANY of these are present:

• Age 65 years or older
• Dangerous mechanism of injury (fall from height ≥1 meter or 5 stairs, axial load to head — such as diving, motor vehicle crash at high speed or with rollover or ejection, motorized recreational vehicle accident, bicycle collision)
• Paresthesias in the extremities

Step 2 — Low-Risk Factors (Permitting Range-of-Motion Assessment)¶

If no high-risk factor is present, the clinician assesses for low-risk factors that allow safe assessment of range of motion:

• Simple rear-end motor vehicle collision (excludes being pushed into oncoming traffic, hit by bus or large truck, rollover, hit by high-speed vehicle)
• Sitting position in the emergency department
• Ambulatory at any time since the injury
• Delayed onset of neck pain (not immediate)
• Absence of midline cervical tenderness

Step 3 — Active Range of Motion¶

If at least one low-risk factor is present, the patient is asked to actively rotate the neck 45 degrees to the left and right. If the patient can do this, the cervical spine can be cleared clinically without imaging.

Performance¶

• Sensitivity: 99.4% (some studies report 100%)
• Specificity: approximately 45.1%
• More specific than NEXUS, meaning fewer patients are sent for unnecessary imaging

Comparison¶

Limitations¶

Both rules apply only to alert, stable trauma patients and have important exclusion criteria:

• Patients under age 16 (NEXUS has been validated in pediatric populations; CCR has not)
• Non-trauma neck pain
• Known cervical spine disease (prior surgery, ankylosing spondylitis, rheumatoid arthritis)
• GCS less than 15
• Unstable vital signs
• Penetrating trauma

Neither rule applies to the thoracolumbar spine. Thoracolumbar imaging decisions are based on clinical judgment, mechanism of injury, and the presence of back pain, tenderness, or neurological deficits.

Key Points¶

• NEXUS and the Canadian C-Spine Rule are validated clinical decision tools for determining the need for cervical spine imaging in alert trauma patients
• Both rules have sensitivity exceeding 99% for clinically significant cervical spine injury
• The Canadian C-Spine Rule has higher specificity than NEXUS, reducing unnecessary imaging
• NEXUS uses five simple exclusion criteria; the CCR uses a three-step algorithm including active range-of-motion testing
• Neither rule applies to obtunded patients, unstable patients, or the thoracolumbar spine
• Age 65 or older mandates imaging under the Canadian C-Spine Rule

References¶

1. 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. National Emergency X-Radiography Utilization Study Group. N Engl J Med. 2000;343(2):94-99. PMID: 10891516. https://pubmed.ncbi.nlm.nih.gov/10891516/
2. 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. https://pubmed.ncbi.nlm.nih.gov/11597285/
3. 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. https://pubmed.ncbi.nlm.nih.gov/14695411/
4. Viccellio P, Simon H, Pressman BD, Shah MN, Mower WR, Hoffman JR; NEXUS Group. A prospective multicenter study of cervical spine injury in children. Pediatrics. 2001;108(2):E20. PMID: 11483830. https://pubmed.ncbi.nlm.nih.gov/11483830/
5. Baratloo A, Ahmadzadeh K, Forouzanfar MM, et al. NEXUS vs. Canadian C-Spine Rule (CCR) in Predicting Cervical Spine Injuries; a Systematic Review and Meta-analysis. Arch Acad Emerg Med. 2023;11(1):e66. PMID: 37840870. https://pubmed.ncbi.nlm.nih.gov/37840870/
6. Beckmann NM, West OC, Nunez D Jr, et al. ACR Appropriateness Criteria® Suspected Spine Trauma. J Am Coll Radiol. 2019;16(5S):S264-S285. PMID: 31054754. https://pubmed.ncbi.nlm.nih.gov/31054754/
7. NEXUS criteria. Radiopaedia.org. https://radiopaedia.org/articles/nexus-criteria

Related Articles¶

• Spine Trauma Imaging Approach
• Spine Radiography (X-ray)
• CT of the Spine