Adverse Impact of Obesity on Lumbar Spine Fusion, Patient-reported Outcomes and Costs
Bibliographic record
Abstract
STUDY DESIGN: Systematic review and meta-analysis. PURPOSE: The objective of this study is to determine the impact of obesity on three key lumbar spinal surgery outcomes: the incidence of spinal nonunion, patient-reported outcome measures (PROMs), and the associated health care costs. SUMMARY OF BACKGROUND DATA: Obesity is a well-recognized risk factor in various medical fields, notably impacting outcomes in orthopedics and traumatology. While there is substantial documentation of the complications associated with obesity in general surgical procedures, the relationship between obesity and spinal surgery outcomes remains less clear. The inconsistency in the evidence presents a significant gap in our understanding of how obesity influences the results of spinal surgeries, particularly in terms of nonunion rates, patient-reported outcomes, and the associated health care costs. METHODS: A systematic search was conducted in PubMed, EMBASE, Scopus, and the Cochrane Library following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Studies comparing patients with or without obesity with lumbar spinal fusion were included. Comparative studies (cohort and case-control) were included. For dichotomous variables such as spinal nonunion, analysis was conducted using odds ratios (OR); for continuous variables such as PROMs [Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and 12/36-Item Short Form Survey (SF-12/36), and costs, analyses were performed using mean differences (MD) or standardized mean differences (SMD)]. RESULTS: Fifteen studies with a pool of 61341 patients were included. Obesity (BMI≥30) was significantly associated with a higher nonunion frequency (OR 2.10, 95% CI: 1.23-3.60, P <0.01). The ODI was significantly worse in the obesity group (MD 6.29, 95% CI: 4.71-7.88, P <0.001). Greater pain was measured by the VAS back pain (MD 0.95, 95% CI: 0.17-1.73, P <0.05) and VAS leg pain (MD 0.94, 95% CI: 0.68-1.20, P <0.001) scales for lumbar surgery patients with obesity. The SF-12/36 showed significantly worse outcomes in patients with obesity (SMD -0.46, 95% CI: -0.82 to -0.09, P =0.01). Hospitalization costs were significantly higher in patients with obesity (SMD 0.09, 95% CI: 0.05-0.12, P <0.001). CONCLUSIONS: This meta-analysis suggests that obesity is significantly associated with higher nonunion rates, poorer patient-reported outcome measures, including Oswestry Disability Index, Visual Analogue Scale, and 36-Item Short Form Survey, and higher hospitalization costs following lumbar spinal fusion. LEVEL OF EVIDENCE: Level III.
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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 | 0.019 | 0.049 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.033 |
| Bibliometrics | 0.008 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".