Clinical decision rule
Canadian C-Spine Rule
The Canadian C-Spine Rule decides whether an alert, stable blunt trauma patient needs cervical spine radiography through three sequential steps — high-risk factors, low-risk factors, and the ability to actively rotate the neck 45 degrees each way — with a reported sensitivity of about 99% for clinically significant injury.
What the Canadian C-Spine Rule means
Canadian C-Spine Rule scores run from 0 to 1, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Imaging not indicated0–0
- Imaging indicated1–1
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | Sensitivity 99.4%, specificity 45.1% | — | Alert, stable blunt trauma patients | — | Stiell IG 2003 |
| Criterion | Higher sensitivity and specificity than NEXUS in direct head-to-head comparison | — | Alert, stable trauma patients | — | Stiell IG 2003 |
| Criterion | Would reduce cervical spine imaging rates relative to NEXUS | — | Emergency department | — | Stiell IG 2001 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
The rule is applied in three sequential steps. Step 1: if any high-risk factor is present — age 65 or over, a dangerous mechanism, or paraesthesias in the extremities — radiography is indicated and the algorithm stops. Step 2: if no low-risk factor is present, range of motion cannot be safely assessed and radiography is indicated. Step 3: if a low-risk factor is present, the patient is asked to actively rotate the neck 45 degrees left and right; if they can, no radiography is needed, and if they cannot, radiography is indicated.
Instrument profile
- Developer
- Ian Stiell and colleagues
- Institution
- University of Ottawa, Canada
- First published
- 2001
- Items
- 3
- Response format
- Three-step branching algorithm
- Score range
- 0 to 1
- Direction
- Lower score = better
- Completion time
- About 2 minutes
- Age range
- Adults 16 and over
- Regions
- Spine
- Conditions
- Blunt cervical spine trauma, Neck injury, Cervical spine fracture
- Validity
- Derived in over 8,900 patients and validated prospectively against NEXUS in over 8,200, where it showed both higher sensitivity and higher specificity.
- Reliability
- Specificity is higher than NEXUS but still low by design. The rule is built to exclude injury safely, not to identify it.
When to use the Canadian C-Spine Rule
Well suited to
- Alert, stable adult blunt trauma patients where cervical spine injury is being considered.
- Settings aiming to reduce cervical spine imaging, where it outperforms NEXUS on both sensitivity and specificity.
Limitations and poor fits
- Non-trauma presentations, penetrating trauma, or patients under 16.
- GCS below 15, unstable vital signs, or any patient who cannot cooperate with active rotation testing.
- Known vertebral disease such as ankylosing spondylitis, rheumatoid arthritis, spinal stenosis or previous cervical surgery.
- Patients returning for reassessment of the same injury, or who are already paralysed.
Canadian C-Spine Rule compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| NEXUS | 5 | 0–1 | The NEXUS low-risk criteria allow the cervical spine to be cleared without imaging after blunt trauma when all five findings are absent — midline cervical tenderness, focal neurological deficit, altered alertness, intoxication and a distracting injury — with a reported sensitivity of about 99% for clinically significant injury. |
| Ottawa Knee Rule | 5 | 0–1 | The Ottawa Knee Rule determines whether an acute knee injury requires radiographs using five criteria — age 55 or over, isolated patellar tenderness, fibular head tenderness, inability to flex to 90 degrees, and inability to bear weight for four steps — and is close to 99% sensitive for clinically significant fractures. |
| Ottawa Ankle Rules | 7 | 0–1 | The Ottawa Ankle Rules determine whether an acute ankle or midfoot injury requires radiographs, based on bone tenderness at four specific sites and the ability to bear weight for four steps; they are approximately 98% sensitive for clinically significant fractures. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
The Canadian C-Spine Rule is a published clinical decision rule. The algorithm is freely reproducible and no licence is required.
References
- Stiell IG, Wells GA, Vandemheen KL, et al.. The Canadian C-Spine Rule for radiography in alert and stable trauma patients. JAMA. 2001.PMID 11597285
- Stiell IG, Clement CM, McKnight RD, et al.. The Canadian C-Spine Rule versus the NEXUS Low-Risk Criteria in patients with trauma. New England Journal of Medicine. 2003.PMID 14695411
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.