The Disaggregation of the Oswestry Disability Index in Patients undergoing Lumbar Surgery for Degenerative Lumbar Spondylolisthesis.

BACKGROUND CONTEXT The Oswestry Disability Index (ODI), is a widely used patient-reported outcome measure (PROM) for assessing functional status in individuals with lumbar spine pathology. The ODI is used by surgeons to determine the initial status and monitor progress after surgery. Compiled ODI data enables comparisons between different surgical techniques. Degenerative lumbar spondylolisthesis (DLS) often causes symptoms such as back pain and neurogenic claudication affecting quality of life and activities of daily living captured by the ODI. Despite extensive studies on ODI changes after spinal surgery, little is known about the characteristics and changes in the different ODI subsections. PURPOSE To analyze the baseline characteristics and changes in total ODI and ODI subsections 2 years after elective lumbar surgery. STUDY DESIGN Retrospective analysis on patients prospectively enrolled who underwent spinal surgery for degenerative lumbar spondylolisthesis from 2016 to 2018. The ODI was assessed preoperatively and 2 years postoperatively. PATIENT SAMPLE A total of 265 patients were included in the study, 60% were female. The mean age of the patients was 67 ± 8 years, and the mean BMI was 30 ± 6 kg/m2. OUTCOME MEASURES The analysis considered the differences in ODI scores before and after surgery, as well as the changes in all ODI subsections 2 years after elective lumbar surgery for DLS. METHODS The analysis evaluated differences in ODI scores and variations in different subsections. Patients without an ODI follow-up at 2 years were excluded from the study. The study utilized the Wilcoxon Signed Rank Test for all pre-post paired samples. The Wilcoxon rank sum test was used for sex and procedure comparisons for overall ODI and ODI subsection analysis. Univariate linear regression was applied for overall and subsection specific ODI outcomes with age and BMI as independent variables, respectively. The statistical significance level was set at p<0.05. RESULTS Improvement in ODI was observed in 242 patients (91%). The highest baseline disability values were found for the questions regarding pain intensity (3.4 ± 1.3), lifting (3.2 ± 1.9), and standing (3.4 ± 1.3). The lowest preoperative functional limitations were observed in sleeping (1.6 ± 1.3), personal care (1.6 ± 1.4), traveling (1.6 ± 1.2) and sitting (1.5 ± 1.4). At the 2-year follow-up, there was significant improvement in all questions and the overall ODI (all p<0.001). The ODI subsections that showed the greatest absolute improvements were changing degree of pain (-2.6), with 89% of patients experiencing improvement, standing (-2.4) with 87% of patients experiencing improvement, and pain intensity (-2.1) with 81% of patients experiencing improvement. The subsections with the least improvement were personal care (-0.6), sitting (-0.7), and sleeping (-0.9). The study found that female patients had a significantly higher preoperative disability in various subsections but showed greater improvement in total ODI compared to male patients (p=0.001). Additionally, improvement in sitting (p<0.001), traveling (p<0.001), social life (p<0.001) and sleeping (p=0.018) were significantly higher in female patients. Older patients showed significantly less improvement in sitting (p=0.005) and sleeping (p=0.002). A higher BMI was significantly associated with less improvement in changing degree of pain (p=0.025) and higher baseline disability in various subsections. Patients who underwent decompression and fusion had significantly higher baseline disability in several subsections compared to those who underwent decompression alone. There was no significant difference between decompression alone and decompression with fusion in terms of overall improvement in the ODI and improvement in the subsections. CONCLUSION These results offer a more comprehensive understanding of ODI and its changes across different subsections. This insight is invaluable for improving preoperative education and effectively managing patient expectations regarding potential post-surgery disability in specific areas.