Differentiation of pain related functional limitations in surgical patients with Lumbar Spinal Stenosis (LSS) using the ODI: a Canadian Spine Outcomes and Research Network (CSORN) study.

BACKGROUND CONTEXT The Oswestry Disability Index (ODI) is the most commonly used outcome measure of functional outcome in spine surgery. The ability of the ODI to differentiate pain related functional limitation specifically related to degenerative lumbar spinal stenosis (LSS) is unclear. PURPOSE The purpose of this study was to determine the ability of the functional subsections of the ODI to differentiate the specific patient limitation(s) from symptomatic LSS and the functional impact of surgery. STUDY DESIGN Analysis of prospectively collected data from the Canadian Spine Outcomes and Research Network (CSORN). PATIENT SAMPLE 1497 lumbar spinal stenosis patients with a dominant complaint of neurogenic claudication, radiculopathy or back pain were identified in the CSORN registry. OUTCOME MEASURES The ODI questionnaire version 2.0 was assessed as an outcome measure. METHODS The difference at baseline and the pre-to-post (1-year) surgical change of the ODI individual questions was assessed. Analysis of variance, two-tailed paired sample Student's t-test were used for statistical analysis. Cohen d was used as an index of effect size, defined as "large" when d ≥0.8. RESULTS The mean age at surgery was 65 (± 11) years and (50.8%) of the patients were female. Preoperatively, highest functional limitations were noted for standing, lifting, walking, pain intensity and social life (mean 3.2, 2.9, 2.5, 2.9, 2.5 respectively). At 1-year follow-up, overall there was a significant improvement in all individual questions and the overall ODI (all p<0.001), with similar patterns seen for each dominant complaint. The greatest effect of surgery was noted in the walking, social life and standing domains (all d≥ 0.81), while personal care, sitting and lifting showed the least improvement (all d≤ 0.51). In subgroup analyses, the overall ODI baseline scores and subsection limitations were statistically significantly higher in females, those without degenerative spondylolisthesis and those undergoing fusion, although these differences were not considered clinically significant. Preoperative differentiation of LSS specific functional limitation and postoperative changes in all subgroups was similar to the overall LSS cohort. CONCLUSIONS The results of this study support the ability of the ODI to differentiate the self-reported pain related functional effects of neurogenic claudication, radiculopathy or back pain from LSS and changes associated with surgical intervention. Disaggregated use of the ODI could be a simple tool to aid in preoperative education regarding specific areas of pain related dysfunction and potential for improvement with LSS surgery.