Cost-Effectiveness of Instrumented Versus Uninstrumented Posterolateral Fusion for Single-Level Degenerative Spondylolisthesis
Bibliographic record
Abstract
STUDY DESIGN: Randomized controlled trial. OBJECTIVE: The aim of this study was to investigate whether instrumented posterolateral fusion is cost-effective compared with uninstrumented posterolateral fusion in elderly patients who undergo fusion surgery for one-level degenerative spondylolisthesis with spinal stenosis. SUMMARY OF BACKGROUND DATA: For patients with persistent symptoms due to degenerative spondylolisthesis, surgical intervention may be recommended, typically decompression and fusion. Evidence on cost-effectiveness of choice of fusion method, related complications, and outcome is sparse. METHODS: This cost-effectiveness analysis is based on a single-center, open-label, randomized controlled trial, where patients with symptomatic degenerative spondylolisthesis were randomly assigned 1:1 to either instrumented or un-instrumented posterolateral fusion. Quality-Adjusted Life Years were obtained from EQ-5D. Use of health services was obtained from patient charts and accumulated until 2 years after index surgery. RESULTS: Of the 108 patients included in the study, 107 patients received the allocated intervention. There were no differences in preoperative demographics. Although the base price for the index instrumented surgery was significantly higher than the index uninstrumented surgery, average cost of surgery was only €146 higher in the instrumented group based on two-year cost data. The instrumented fusion group had a significantly lower reoperation rate [1/54 (1.9%)] than the uninstrumented fusion group 7/53 (13.2%), significantly less visits to the outpatient clinic, less magnetic resonance imaging performed and fewer days of hospitalization. The base case incremental cost-effectiveness ratio was estimated at €1536 per QALY gained over a two-year time horizon. Instrumented fusion was favored over uninstrumented fusion in sensitivity analyses including all reoperations or using hospital reimbursement rate. CONCLUSION: Instrumented fusion is cost-effective compared uninstrumented fusion, with an incremental cost-effectiveness ration well below the standard range of cost-effectivenes, the difference in cost was driven by lower reoperation rates and less health care resource utilization over a two-year time horizon.
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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 | 0.004 | 0.010 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.005 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.009 | 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".