The Effect of Axial Torsion on the Mechanical Properties of the Annulus Fibrosus
Bibliographic record
Abstract
STUDY DESIGN: In-vitro study of the tissue mechanics of annulus fibrosus. OBJECTIVE: To determine the effect of axial torsion on the mechanical properties of the inter- and intralamellar matrices. SUMMARY OF BACKGROUND DATA: Axial torsion, when combined with repetitive flexion, has been associated with an increased risk of intervertebral disc herniation. However, the mechanisms behind this relationship are poorly understood. METHODS: Bovine intervertebral discs (IVDs) from the caudal region were exposed to a combination of either 0° or 12° of static axial torsion and 0 N or 1000 N of compression for 2 hours in an attempt to created micro-damage to the IVD. Following the loading protocol, one multilayered sample and two single layer samples were dissected from the annulus fibrosus to undergo tensile testing of the inter- and intralamellar matrices. Histological staining was also performed. RESULTS: The strength of the interlamellar matrix was not affected by axial torsion or compression, suggesting that torsion did not damage the interlamellar matrix. However, intralamellar matrix strength of samples exposed to axial torsion, regardless of compressive loading magnitude, was 48% lower than those from samples that were not exposed to torsion (P < 0.001). Similarly, intralamellar matrix stiffness of samples exposed to axial torsion was 42% lower than from samples that were not exposed to torsion (P = 0.010). Additionally, histological analysis demonstrated more disruption within individual lamellae of the samples exposed to axial torsion compared with samples that were not. CONCLUSION: This study suggests that axial torsion damages the components of the intralamellar matrix as a result of the strain it puts on the matrix, thus making the intervertebral disc more susceptible to herniation. LEVEL OF EVIDENCE: N/A.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.000 |
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".