Validating the Hierarchical Nature of the AO Spine Upper Cervical Spine Injury Classification System
Bibliographic record
Abstract
STUDY DESIGN: Global cross-sectional survey. OBJECTIVE: To validate the hierarchical nature of the AO Spine Upper Cervical Spine Injury Classification (UCIC) across AO geographical regions/practice experience. SUMMARY OF BACKGROUND DATA: To create a universally validated scheme with prognostic value, AO Spine established an upper cervical spine injury classification involving three elements: injury morphology (region: I-occipital condyle and craniocervical junction; II-C1 ring and C1-2 joint; III-C2 and C2-3 joint), and (subtype: A-isolated bony injury; B-bony/ligamentous injury; C-displaced/translational injury), neurological status [N0-intact; N1-transient deficit; N2-radiculopathy; N3-incomplete spinal cord injury (SCI); N4-complete SCI, and NX-unable to examine], and case-specific modifiers (M1-injuries at risk of nonunion; M2-injuries at risk of instability; M3-patient specific factors; M4-vascular injury). MATERIALS AND METHODS: Totally, 151 AO Spine members (orthopaedic and neurosurgery) were surveyed globally regarding the severity (zero-low severity to 100-high severity) of each UCIC variable. Primary outcomes were differences in perceived injury severity score (ISS) over various geographic/practice settings, level of experience, and subspecialty. RESULTS: One hundred forty-eight responses were received. There was an increase in median perceived severity as each anatomic region (I-III) progressed from types A to B to C. Neurological status progressed similarly, except N1 and N2 were perceived similarly. Modifier M2 was perceived more severely than M3. There were no differences in ISS among levels of surgeon experience. There were small geographic differences with respondents from North and Central and South America perceiving types IC ( P =0.003), IIB ( P =0.003), and IIIB ( P =0.003) somewhat more severely than other regions. Neurosurgeons perceived types IB ( P =0.002) and IIIB ( P =0.026) as more severe than orthopaedic spine surgeons. CONCLUSIONS: The AO Spine UCIC has overall excellent hierarchical progression in subtype ISS. These findings are consistent across geographic regions, spine subspecialty training and experience levels.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.021 | 0.034 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".