Cervical spine imaging rules
Both rules aim to avoid unnecessary imaging after trauma; in the 2003 head-to-head study the Canadian C-Spine Rule was more sensitive and specific than NEXUS.
| Characteristic | Canadian C-Spine | NEXUS |
|---|---|---|
| Clinical question | Does an alert, stable trauma patient need cervical spine imaging? | Can cervical spine imaging be safely avoided after blunt trauma? |
| Outcome predicted | Clinically important cervical spine injury | Clinically significant cervical spine injury |
| Time horizon | Index visit | Index visit |
| Intended population | Canadian emergency departments. | 21 US emergency departments. |
| Evidence level | Strong evidence | Strong evidence |
| Validation | Derivation (Stiell 2001): 100% sensitivity and 42.5% specificity for clinically important cervical spine injury. | NEXUS prospective validation (Hoffman 2000): Sensitivity 99.6%, specificity 12.9%, NPV 99.9% for clinically significant injury. |
| Discrimination | — | — |
| Calibration | — | — |
| Geographic applicability | — | — |
| Guideline status | — | — |
| Important limitations |
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Inputs required
Which variables each model uses. Models with more inputs are not automatically better — validation in your population matters most.
| Input | Canadian C-Spine | NEXUS |
|---|---|---|
| Alert (GCS 15), stable trauma patient where cervical spine injury is a concern | ●used | –not used |
| Age ≥ 65 years | ●used | –not used |
| Dangerous mechanism | ●used | –not used |
| Paraesthesias in extremities | ●used | –not used |
| Simple rear-end motor vehicle collision | ●used | –not used |
| Sitting position in the emergency department | ●used | –not used |
| Ambulatory at any time since injury | ●used | –not used |
| Delayed onset of neck pain | ●used | –not used |
| Absence of midline cervical spine tenderness | ●used | –not used |
| Able to actively rotate neck 45° left and right? | ●used | –not used |
| Posterior midline cervical spine tenderness | –not used | ●used |
| Evidence of intoxication | –not used | ●used |
| Altered level of alertness | –not used | ●used |
| Focal neurological deficit | –not used | ●used |
| Painful distracting injury | –not used | ●used |
Comparison shows model characteristics only. Different models predict different outcomes in different populations, so their numerical results are not directly comparable.