An in vitro biomechanical study of the effects of surgical modification upon the canine lumbosacral spine
Bibliographic record
Abstract
Summary The purpose of this study was to determine the impact of surgical decompressive procedures upon stiffness of cadaveric canine lumbosacral motion units in the dorsoventral plane. Thirty-four grossly normal lumbosacral specimens were potted, in aluminum channeling with polymethylmethacrylate, and subjected to four-point bending in dorsiflexion and ventroflexion, using a universal testing machine (Instron MA). In order to determine its yield point, each specimen was non-destructively tested before and after surgical modification and then tested to failure in ventroflexion. Dorsal laminectomy (L) did not have a significant effect upon stiffness of the lumbosacral motion unit in dorsiflexion or ventroflexion, when compared with the control group. Since this also involved excision of the interspinous and supraspinous ligaments, removal of these structures alone also did not have any significant effect upon dorsoventral stiffness in vitro. Compared with the control group, the stiffness in the other groups changed as follows: addition of discectomy (LD) did not have a statistically significant effect in dorsiflexion, but decreased mean stiffness 33.1% (95% CI 29.0 to 37.2) in ventroflexion. Dorsal laminectomy combined with bilateral facetectomy (LF) decreased stiffness 43.5% (95% CI 39.4 to 47.6) in dorsiflexion, and 30.9% (95% CI 26.8 to 35.0) in ventroflexion. The combination of dorsal laminectomy, facetectomy and discectomy (LFD) decreased the stiffness 47.9% (95% CI 43.8 to 52.0) in dorsiflexion and 56.4% (95% CI 52.3 to 60.5) in ventroflexion. This decrease in stiffness in ventroflexion was significantly greater than with laminectomy and facetectomy alone (25% less stiff; 95% CI 20.9 to 29.1).
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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) | 0.000 | 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) | 0.002 | 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".