Early Sacral Stress Fracture after Reduction of Spondylolisthesis and Lumbosacral Fixation: Case Report
Bibliographic record
Abstract
OBJECTIVE AND IMPORTANCE: Early sacral fracture is an extremely rare complication of instrumented lumbosacral fusion seen in older, osteopenic women. Previous reports have attributed the problem to the use of multisegmental (three or more levels) fixation, with the transfer of stress forces from rigid spinal implants to the sacrum. We report the only case, to the best of our knowledge, of early sacral fracture after a two-level lumbosacral fusion and the only case of early sacral fracture after reduction of spondylolisthesis. CLINICAL PRESENTATION: A patient presented with a sudden recurrence of low back and buttock pain a few days after lumbosacral decompression, reduction of L5-S1 Grade II spondylolisthesis, and instrumented L5-S1 fusion, including posterior lumbar interbody fusion. A transverse sacral fracture was found on plain x-rays 4 weeks later. INTERVENTION: Symptoms improved with brace therapy and medical treatment for osteoporosis. CONCLUSION: Early sacral fracture is a rare cause of pain after instrumented lumbosacral fusion. Although the transfer of loads from rigid spinal implants to adjacent segments is particularly problematic for multisegmental fusions, patients with short-segment constructs may also be affected. Active reduction of spondylolisthesis may provide additional adjacent segment stress contributing to this complication.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.004 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.009 | 0.004 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".