The Strength Profile of the Thoracolumbar Endplate Reflects the Sagittal Contours of the Spine
Bibliographic record
Abstract
STUDY DESIGN: human cadaveric biomechanical study of indentation tests on the thoracolumbar vertebral endplates. OBJECTIVE: to map the strength profile of the thoracolumbar endplates using indentation testing, and to document any changes in this profile with vertebral level. SUMMARY OF BACKGROUND DATA: the strength profile of the lumbosacral endplate was described previously. Based on these data, we hypothesized that the periphery of the endplate would be stronger than the center and that the strength profile would vary with the sagittal contour and level of the spine. METHODS: indentation testing was performed on the T9, T12, and L2 endplates of fresh-frozen human cadaver spines, using a materials testing machine. A 3-mm hemispherical indenter was lowered at 0.2 mm/s to a depth of 3 mm to produce local endplate failure. A minimum of 25 indentations were performed in a rectangular grid (rows: lateral, left to right; columns: A-P, anterior to posterior). Three-way analysis of variance was used to address changing strength profile patterns. RESULTS: there were highly significant variations of indentation strength across the endplates in both the lateral and anterior to posterior directions. Each row of indentations was significantly stronger than the rows anterior to it (P < 0.04), except for the most anterior row. The most lateral columns were stronger than the central columns (P < 0.05). The ratio of the mean strength of the posterior row compared to that of the anterior row was significantly different across levels (P = 0.026). CONCLUSION: the periphery of the thoracolumbar endplate was stronger than the center. The difference in posterior to anterior ndplate strength ratio between vertebral levels suggests a relative strength increase in the anterior aspect of the endplate with rostral ascent into the thoracic spine.
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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 | 0.001 | 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) | 0.005 | 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 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".