A Radiographic Analysis of Lumbar Fusion Status and Instrumentation Failure After Complex Adult Spinal Deformity Surgery With Spinopelvic Fixation
Bibliographic record
Abstract
STUDY DESIGN: A retrospective review of prospectively collected data. OBJECTIVE: The objective of this study was to investigate the fusion status of the lumbar spine and lumbosacral junction at 2 years postoperatively after complex adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: Achieving fusion is crucial for maintaining optimal alignment in ASD surgery. However, prospective data assessing fusion status using large patient populations are lacking in this patient population. MATERIALS AND METHODS: Postoperative radiographs of 162 patients from the Scoli-Risk-1 database, who underwent complex ASD surgery with fusion to the sacrum, were evaluated by 3 independent spine surgeons at 6-week, 6-month, and 2-year follow-up. The fusion rate of the lumbar spine segments at a 2-year follow-up was determined by using previously published radiographic grading criteria. We also assessed the prevalence of instrumentation failures. RESULTS: The interrater reliabilities for grading the fusion status were overall fair at each level evaluated (Fleiss κ, 0.337-0.439). Overall, 70.3% (114/162) demonstrated the solid fusion of the entire lumbar spine at a 2-year follow-up. The fusion rates of each segment were L1/L2: 87.0%, L2/L3: 82.0%, L3/L4: 83.9%, L4/L5: 89.5%, and L5/S1: 89.5%. Pedicle screw loosening was the most frequent implant failure throughout the observation period (9.2%, 11.6%, and 11.0% at 6-wk, 6-mo, and 2-y follow-up, respectively). No rod breakage was observed at 6 weeks, increasing to 9.8% at 2-year follow-up. The prevalence of postoperative proximal junctional kyphosis was 5.5% at 6 weeks, showing no difference at 2 years postoperative. CONCLUSIONS: In this series of complex ASD surgeries often requiring 3-column osteotomies, 70.3% showed solid fusion of the entire lumbar spine, including the lumbosacral junction. The lumbosacral segments showed a relatively high fusion rate at a 2-year follow-up likely due to the frequent use of anterior column support and graft. The prevalence of rod breakage increased as follow-up proceeded to 9.8%, which was most commonly observed at the lumbosacral junction. LEVEL OF EVIDENCE: Level IV.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.004 |
| 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".