An In Vitro Study on the Effects of Freezing, Spine Segment, Repeat Measurement, and Individual Cord Properties on Cord Interstitial Pressure
Bibliographic record
Abstract
In Brief Study Design. In vitro study of the spinal cord tension and pressure relationships before and after thawing in 6 different spinal cord segment from 2 individual pigs. Objectives. To determine if frozen and thawed spinal cord segments had different tension/cord interstitial pressure(CIP) relationships to fresh spinal cord segments. In addition, we will determine if the cord level, individual cord properties, and repeated CIP measurements affect the tension/CIP relationships. Summary of Background Data. Spinal cord distraction is a known cause of spinal cord injury. Several articles published on the pathophysiology of the cord distraction injury suggest that the underlying mechanism of injury is a microvascular ischemic event. We have previously described an increase in CIP with spinal cord distraction, pressures average 23 mmHg at 1 kg loads. Methods. Six cord segments harvested from 2 pigs contained cervical, thoracic, and lumbar segments, and underwent distraction using a series of 7 calibrated weights from 0 to 1000 g weight. The cords were measured at each level of distraction. The cords were then frozen at −20°C for a period of 2 weeks, and then thawed and retested. Multiple linear regression was then performed. Results. There was no difference between the fresh and the frozen-thawed cords; there was statistical difference between the 2 pigs (18 mmHg) (P < 0.001). There are differences between the cervical and the thoracic cord segments (P < 0.001), and between cervical and lumbar cord segments (P = 0.056). There is a significant relation between the tension applied and CIP. Repeated trials showed no drift with repeated measures. Conclusion. Freezing and thawing spinal cords has no effect on the CIP/tension curves. Cord interstitial pressure developed is dependant on cord tension, cord level, individual cord properties, but not on the number of repetitions carried out while testing the spinal cord. Spinal cord distraction may cause spinal cord injury through a Laplace's law elevation of cord interstitial pressure during cord tensioning. We determined that fresh and frozen/thawed cords had identical tension/cord interstitial pressures. In addition, the cord level and the individual cord properties affected the pressures developed, but repeated cord pressure measurements did not.
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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) | 0.000 | 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".