ISSLS Prize Winner: How Loading Rate Influences Disc Failure Mechanics
Bibliographic record
Abstract
STUDY DESIGN: Mechanically induced disruption and subsequent microscopic investigation of lumbar intervertebral discs following a previously published testing protocol, but using a much higher rate of loading. OBJECTIVE: To explore if loading rate affects the internal disruption mechanics of lumbar intervertebral discs. SUMMARY OF BACKGROUND DATA: The failure mechanics of some bone-ligament-bone constructs vary with the rate of tensile load application. Like many ligaments, recent reports indicate that the mechanical response of the disc wall varies with strain-rate. It is possible that the internal failure mechanics of the disc wall also varies with strain-rate. METHODS: Nuclear pressurization was used to deliver sudden pressure impulses directly to the nucleus of ovine lumbar motion segments. Pressure impulses were delivered to 12 neutrally positioned motion segments, and 15 motion segments held at 7° flexion. Aside from loading rate, testing was conducted in the same manner as 2 previously published studies that employed a gradual nuclear pressurization regime. Following testing, the internal damage resulting to each disc was analyzed using micro-CT and serial microscopy in tandem. RESULTS: Radial tears of the medioposterior disc wall were the most frequent cause of disc failure. In most cases, radial tears involved a combination of annular and endplate disruption: Neutrally positioned discs frequently suffered tears within the superior cartilaginous endplate adjacent to the transition zone and/or inner anulus. Flexed discs frequently suffered tears adjacent to the outer anulus at the cartilaginous/vertebral endplate junction, or within the vertebral endplate. Both groups frequently suffered endplate tears adjacent to the mid anulus at the inferior cartilaginous/vertebral endplate junction. CONCLUSION: The internal morphologies of the disc disruptions created in this study using high strain-rate impulse pressurization differed significantly from those documented previously for both neutrally positioned and flexed discs subjected to gradual low strain-rate pressurization. These morphologic differences show that the internal failure mechanics of lumbar intervertebral discs vary with the rate of internal radial load application.
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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 | 0.000 |
| 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) | 0.001 | 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 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".