Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)



Committee Chair(s)

M. Scott DeBerard


M. Scott DeBerard


Susan L. Crowley


Michael P. Twohig


JoAnn T. Tschanz


Edward M. Heath


Lumbar fusion performed among injured workers has dramatically increased over the past two decades, coinciding with the increased use of more advanced surgical technology. Despite recent changes in how this surgery is performed, few outcome studies have been conducted, particularly among workers compensation populations. In prior studies, several biopsychosocial risk factors were found to be predictors of functional outcomes of lumbar fusion. Considering the recent changes in lumbar fusion surgery, there is a need to identify how patient outcomes have changed among injured workers, and whether a biopsychosocial model continues to be predictive of outcomes. The current study aimed to address multidimensional patient outcomes associated with lumbar fusion and examine the relationship between presurgical biopsychosocial variables and outcomes by testing the predictive efficacy of a multiple variable model.

Injured workers (N = 245) who underwent their first lumbar fusion between 1998 and 2007 were included in a retrospective-cohort study performed in two phases that involved coding presurgical information documented in patient medical charts in the Worker's Compensation Fund of Utah computer database (Phase 1) and administering a telephone outcome survey with patients at least 2 years post-surgery (Phase 2). Of the total sample, 45% (n = 110) of patients were contacted and completed follow-up outcome surveys on several measures of patient satisfaction, quality of life, fusion status, dysfunction level, disability status, pain, and general physical and mental health functioning.

Results revealed injured workers reported a solid fusion rate of 89.0%, disability rate of 28.7%, and a poor outcome rate of 57.1%. Multiple linear regression analyses demonstrated an eight variable model was a statistically significant predictor of multiple patient outcomes. Involvement of a nurse case manger, vocational rehabilitation, and litigation at the time of fusion were the most prominent predictors across outcome measures, while age and depression history showed modest prediction of outcomes. Prior back operations, number of vertebral levels fused, and type of instrumentation showed no statistically significant prediction of outcomes. Results were evaluated and compared to prior lumber fusion studies on injured worker and fusion outcome literature, in general. Specific implications for our findings and limitations associated with this study were addressed.




This work made publicly available electronically on April 12, 2012.

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