Vertebral Bone Quality Score as a Predictor of Pedicle Screw Loosening Following Surgery for Degenerative Lumbar Disease
Bibliographic record
Abstract
STUDY DESIGN: Retrospective study. OBJECTIVE: To investigate whether magnetic resonance imaging-based vertebral bone quality (VBQ) score can predict pedicle screw loosening in patients who underwent pedicle screw fixation, and to compare, which measurement, the VBQ score or the Hounsfield unit (HU) value, is more predictive of pedicle screw loosening. SUMMARY OF BACKGROUND DATA: In clinical work, we found that patients with screw loosening had higher VBQ scores. In addition, some studies have found a correlation between VBQ scores and osteoporosis. PATIENTS AND METHODS: Patients who were treated with lumbar pedicle screw fixation were reviewed. The VBQ score was measured using magnetic resonance imaging scans. The HU value for L1 to L4 lumbar bone mineral density was measured with computed tomography scans. Logistic regression analysis was used to identify factors associated with pedicle screw loosening. Receiver-operating characteristic curve analysis was used to evaluate the value of VBQ scores in predicting pedicle screw loosening. RESULTS: A total of 156 patients were included in the final analysis. The pedicle screw loosening rate was 35% (55 of 156 patients). The postoperative low-back pain visual analog scale score was higher in the loosening group (3.0 ± 2.0 vs . 2.4 ± 1.8; P < 0.05). The VBQ score was higher in the loosening group than in the nonloosening group (3.28 ± 0.58 vs . 2.82 ± 0.50; P < 0.01). In multivariable analysis, nonsingle segment fixation [odds ratio (OR): 3.992; 95% CI: 1.643-9.701; P = 0.002], lowest instrumented vertebrae at S1 (OR: 3.378; 95% CI: 1.387-8.226; P = 0.007), HU value (OR: 0.988; 95% CI: 0.976-1.000; P = 0.047), and VBQ score (OR: 3.908; 95% CI: 1.624-9.405; P = 0.002) were factors associated with screw loosening. The areas under the curve for using the VBQ score and HU value to predict pedicle screw loosening were 0.720 and 0.702, respectively. The optimal VBQ score threshold was 3.05 for predicting pedicle screw loosening (sensitivity: 0.655; specificity: 0.713). CONCLUSIONS: The VBQ score was an influential factor associated with lumbar pedicle screw loosening, and a higher VBQ score was significantly correlated with a higher risk of screw loosening. The VBQ score was a better predictor of pedicle screw loosening than the HU value in patients who underwent pedicle screw fixation for degenerative lumbar disease.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".