title: Predictors of reoperation-free survival following decompression-alone lumbar spine surgery for on-the-job injuries.
abstract: BACKGROUND
  Workers' compensation patients are known to be associated with inferior outcomes following lumbar surgery. We investigated demographics and clinical characteristics between the reoperative and non-reoperative group of patients undergoing decompression-alone lumbar surgery (discectomy and/or laminectomy) for on-the-job injuries (OJI) at our institute, and evaluated its possible impact on the reoperation-free survival (RFS).
  
  
  METHODS
  A retrospective analysis of patients undergoing lumbar surgery for OJI between 2003 through 2010 by a single surgeon (A.N.) was performed. A comparison of baseline clinical and demographic parameters between the two groups was compared using Fisher's exact test for the categorical variables and the independent t-test (2-tailed) for the continuous variables. Overall, RFS was presented in Kaplan-Meier curves and the RFS difference was compared using log-rank (Mantel-Cox) test. Cox proportional hazard model was used for the univariate and multivariate analysis and hazard ratios with 95% confidence intervals were reported.
  
  
  RESULTS
  About 92 patients with mean age 48.07 ± 10.10 years and mean follow-up of 36.4 (range 24.3-66.0) months were included. About 38 (41.3%) patients underwent reoperation for failed decompression-alone procedures whereas the non-reoperative cohort comprises 54 (58.7%) patients. Female gender (p = 0.015) and history of previous surgery (p = 0.05) were associated with a higher chance of reoperation. Majority of the reoperations (20/38, 52.6%) were performed within the first 2 years, with a RFS at the end of 2 years being 78.3% (n = 72) and 58.9% (n = 53) at 5 years. Cox-regression analysis did not demonstrate any influence of patients and treatment-related factors on the RFS.
  
  
  CONCLUSIONS
  There is a substantial risk of redo surgeries following decompression-alone lumbar procedures for OJI. As patient and treatment-related factors did not influence the reoperation rates and RFS in this study, it appears that workman compensation status of patients is inherently associated with poor outcomes following spine surgeries.
authors.affiliation: Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, USA.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kukreja
authors.affiliation: Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, USA.
authors.forename: Piyush
authors.initials: P
authors.lastname: Kalakoti
authors.affiliation: Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, USA.
authors.forename: Osama
authors.initials: O
authors.lastname: Ahmed
authors.affiliation: Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, USA. Electronic address: ananda@lsuhsc.edu.
authors.forename: Anil
authors.initials: A
authors.lastname: Nanda
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D019299:Decompression, Surgical; D017586:Diskectomy; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D007796:Laminectomy; D017116:Low Back Pain / Q000601:surgery; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D060051:Occupational Injuries / Q000601:surgery*; D016017:Odds Ratio; D011379:Prognosis; D016016:Proportional Hazards Models; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016896:Treatment Outcome; D014942:Workers' Compensation / Q000706:statistics & numerical data*
keywords: Lumbar spine surgery; On-job-injuries; Reoperation; Workers’ compensation