How Well Does the Oswestry Disability Index Perform Among Patients Undergoing Lumbar Spinal Surgery? – An observational prospective cohort study

Background: The objective of this study was to explore the internal consistency and factor structure of the Oswestry Disability Index among patients undergoing spinal surgery. The sample consisted of 1,990 patients who underwent lumbar spinal surgery at a university hospital between 2018 and 2021. Methods: The patients responded to the Oswestry Disability Index within 2 months before surgery. Cronbach’s alpha was used to assess the internal consistency. The factor structure was evaluated using exploratory and confirmatory factor analyses. Results: The internal consistency of the Oswestry Disability Index was found to be good, with an alpha of 0.86. An exploratory factor analysis revealed unidimensionality. Confirmatory factor analysis showed at least moderate correlations between the main factor “disability” and all the individual items. The highest correlations were found for items “traveling,” “social life,” “sex life” and “personal care.” Discussion: The result of this study was in line with other research that have reported a good internal consistency of the Oswestry Disability Index. The result of this study contradicts the previous research that have found a multiple-factor structure of the Oswestry Disability Index. The study was conducted in a single, highly specialized university clinic; therefore, the results might differ in primary care. Conclusions: The Oswestry Disability Index is a unidimensional and internally consistent scale that can be used to assess the severity of disability in patients undergoing lumbar spinal surgery. In the studied population, “traveling,” “social life,” “sex life” and “personal care” were the most important items to define the severity of disability, while “walking” and “standing” were the least important items. Trial registration Not applicable