INFLUENCE OF HIGH PELVIC INCIDENCE ON OPERATIVE DIFFICULTY IN PATIENTS TREATED SURGICALLY FOR DEGENERATIVE LUMBAR SPONDYLOLISTHESIS
Bibliographic record
Abstract
The objective of this study was to determine if the degree of pelvic incidence (PI) influenced the difficulty of surgery in patients undergoing treatment for degenerative spondylolisthesis. This is a retrospective cohort study of patients enrolled between 2015 - 2021 in the Canadian Spine Outcomes and Research Network (CSORN) multi-centred prospective study on the assessment and management of DLS who underwent decompression or decompression and fusion, and who had baseline radiographic measures. Patients were divided into two groups based on a preoperative PI of >60° or < 6 0°. Baseline demographic, clinical, radiographic, and procedure factors were compared between the groups stratified by procedure type (decompression vs. decompression and fusion). Of the patients that had a decompression alone, 85 had PI 60°. Demographic factors, chief complaint, grade of spondylolisthesis, and preoperative patient-rated outcome measures (PROM) were similar between the two groups. Blood loss was similar in both groups, but patients with a high PI had significantly longer operative times (96 minutes vs. 82 minutes). Of the patients that had a decompression and fusion, 193 had PI 60°. Demographics and preoperative PROMs were similar between the groups except more females were in the high PI group (71% vs 60%). Patients in the high PI group were also more likely to have grade II spondylolisthesis (41% vs. 26%) and were less likely to have minimally invasive surgery (16% vs. 29%). Operating time was similar between groups; however, blood loss was significantly increased in the patients that had a high PI (M = 400 vs. 300 mL). Intraoperative complications and length of stay were not different between groups, regardless of procedure. Overall, this study demonstrates that high PI is associated with increased operative time and blood loss, indicating there may be unique challenges with this population. Technical difficulties may arise due to larger exposures required and challenging angles seen in patients with a high PI. Thus, operative difficulties should be anticipated when treating patients with a PI >60°.
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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 | 0.006 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".