Improvement of Oswestry disability index and its test of reliability and validity

English Keywords:Low back pain  Scale  Outcome  Evaluation  Minimally invasive

English Abstract:

  【Abstract】 Objectives: To make improvement to the Oswestry disability index(ODI) to make it suitable and applicable for short-term outcomes evaluation after surgical treatment of low back pain in China. Methods: The follow-ups for low back pain were proceeded in 100 patients before therapy and 3 months after operation, and the items with poor compliance were removed. The items fit for short-term efficacy evaluation were selected to construct the modified ODI in China. Five items in ODI ("personal care", "lifting", "sex life", "social life" and "traveling") were replaced with five items in modified ODI("lower limb numbness", "turn over in bed", "stand up when sitting", "homemaking" and "employment"). 41 low back pain patients undergoing minimally invasive(n=22) and open(n=19) disc surgery were evaluated by Japanese Orthopaedic Association(JOA) low back pain score, ODI and modified ODI. The time points were before therapy and after operations(1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks and 24 weeks after operation). The reliability of modified ODI was evaluated by internal consistency and Split-half reliability. The construct validity and content validity of scale were evaluated by factor analysis and Pearson correlation coefficient. Results: The Cronbach′s α coefficient of modified ODI was 0.849, the Cronbach′s α coefficient of items in the scale was between 0.813 and 0.861. The split-half reliability coefficient was 0.894. The factor analysis showed KMO value was 0.857(P＜0.001). The principal component analysis showed that all the 10 factors were extracted, and the common factor cumulative variance contribution rate was 67.2%. The content validity test showed modified ODI was significantly correlated with JOA score(r=-0.695, P<0.001) and ODI score(r=0.819, P<0.001). Conclusions: With good reliability and validity, modified ODI can be used to make the assessment for low back pain in China and to evaluate short-term outcomes of surgery for low back pain.