Anterior Occiput to Axis Screw Fixation
Bibliographic record
Abstract
STUDY DESIGN: This biomechanical study used flexibility testing on fresh-frozen human cadaveric specimens (occiput to C3) and compared the range of motion and neutral zone for three occipitocervical fixation techniques. OBJECTIVES: To contrast the stabilization provided by a new technique of anterior occipitocervical screw fixation with two other commonly used posterior occipitocervical fixation techniques. SUMMARY OF BACKGROUND DATA: There are no published reports describing this novel technique of anterior occipitocervical screw fixation. METHODS: Six human occipitocervical spine specimens were mounted in a custom-designed, spine-testing machine that applied a pure moment in flexion-extension, lateral bending, and axial rotation. The specimens were tested intact, after an odontoid osteotomy with capsular injury, and after each of three fixation methods: posterior wiring, posterior plate fixation with C1-C2 transarticular screws, and finally with anterior occipitocervical screws. Intervertebral motion was measured with an optoelectronic measurement system, and the range of motion and neutral zone were the kinematic variables measured and used for analysis. RESULTS: In flexion and extension testing, the posterior plate with transarticular screws provided greater stabilization than posterior wiring or anterior occipitocervical screws. In lateral bending and rotation, the anterior screws were similarly effective to the posterior plate, both of which were more effective than posterior wiring. CONCLUSION: The anterior screw fixation technique was as effective as a posterior plate with transarticular screws in stabilizing between the occiput and C2 in axial rotation and lateral bending. In extension and flexion, the anterior screw technique was not as effective as a posterior plate with transarticular screws in providing stability.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 teacher head, 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".