The Influence of Intervertebral Disc Shape on the Pathway of Posterior/Posterolateral Partial Herniation
Bibliographic record
Abstract
STUDY DESIGN: Basic scientific investigation employing the medical imaging techniques of contrast-enhanced plane film radiographs and computed tomography in addition to gross dissection techniques on a sample of spines. OBJECTIVE: To document the specific posterior/posterolateral pathway of mechanically-induced intervertebral disc (IVD) herniation as the result of repetitive loading and disc geometry. SUMMARY OF BACKGROUND DATA: In vitro cadaveric and animal investigations have indicated that the posterior/posterolateral aspects of the IVD are most susceptible to damage leading to herniation, and that cyclic bending is the most potent variable influencing herniation. The IVD in horizontal cross-section ranges in shape from ovoid to limacon (kidney-shaped) which influences stress distributions. The purpose of this investigation was to determine the role of the IVDs shape and size on influencing the pathway of herniation. METHODS: Compressive loads (1472 N) in conjunction with 7000 repetitive cycles of flexion-extension were applied to 22 porcine motion segments. Computed tomography images and contrast-enhanced plane file radiographs, in addition to dissection techniques were used to evaluate the progression of herniations. A logistical regression assessed the links between endplate size and shape, and the probability of a specific herniation type (directionally diffuse or directionally concentrated). RESULTS: A total of 18 out of the 22 specimens exhibited detectable anular damage in the posterior/posterior lateral direction. Of the 18 specimens, 17 were partial herniations while one incurred a full herniation. IVD shape was found to be predictive of the pathway of herniation (P = 0.0329); oval IVD shapes were more likely to herniate in a directionally diffuse manner (6/18), while limacon IVDs were more likely to herniate in a directionally concentrated manner (12/18). CONCLUSION: The shape of the IVD appears to be predictive of the pathway of IVD herniation.
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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 | 0.001 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".