Study Design. Historical cohort study.
Specific Aims. To determine objective outcomes of return to work (RTW), permanent disability, post surgical complications, opiate utilization, and re-operation status for chronic low back pain subjects with lumbar fusion. Similarly, RTW status, permanent disability, and opiate utilization were also measured for non-surgical controls.
Summary of Background Data. A historical cohort study of workers’ compensation (WC) subjects with lumbar arthodesis and randomly selected controls to evaluate multiple objective outcomes has not been previously published.
Methods. 725 lumbar fusion cases were compared to 725 controls who were randomly selected from a pool of WC subjects with chronic low back pain (CLBP) diagnoses with dates of injury between 01/01/1999 and 12/31/2001. The study ended on 1/31/06. Main outcomes were reported as RTW status two years after the date of injury (for controls) or two years after date of surgery (for cases). Disability, re-operations, complications, opioid usage, and deaths were also determined.
Results. Two years after fusion surgery, 26% (n=188) of fusion cases had RTW, while sixty-seven percent (n=483) of non-surgical controls had RTW (p=<.001) within 2 years from the date of injury. The re-operation rate was 27% (n=194) for surgical patients. Thirty six percent (n=264) of the lumbar fusion subjects had complications. Permanent disability rates were 11% (n=82) for cases and 2% (n=11) for non-operative controls (p=<.001). Seventeen surgical patients and 11 controls died by the end of the study (p=0.26). For lumbar fusion subjects, daily opioid use increased 41% after surgery, with 76% (n=550) of cases continuing opioid use after surgery. Total number of days off work was more prolonged for cases compared to controls, 1,140 days and 316 days respectively (p<.001). Final multivariate, logistic regression analysis indicated the number of days off prior to surgery OR, 0.94(95% CI, 0.92-0.97), legal representation OR, 3.43(95% CI, 1.58-7.41), daily morphine usage OR, 0.83(95% CI, 0.71-0.98), re-operation OR, 0.42(95% CI, 0.26-0.69) and complications OR, 0.25(95% CI, 0.07-0.90) are significant predictors of RTW for lumbar fusion patients.
Conclusion. Lumbar fusion for the diagnoses of disc degeneration, disc herniation and/or radiculopathy in a WC setting is associated with significant increase in disability, opiate use, prolonged work loss, and poor RTW status.