Can clinical scores substitute for objective walking capacity tests? A prospective study of subjective, functional, and radiographic correlates in lumbar spinal stenosis.

Abstract

This prospective study aimed to determine the correlation between the objective 6-minute walk test (6MWT) and key patient-reported outcomes, clinician-reported outcomes, and radiographic parameters in patients with lumbar spinal stenosis (LSS) to evaluate whether clinical scores can substitute for objective walking capacity assessment. The 6MWT was conducted in strict accordance with established guidelines. Japanese Orthopaedic Association (JOA) scale scores were assessed by two experienced spine surgeons, while a visual analog scale for pain or numbness, the Oswestry Disability Index (ODI), the Back Disability Index (BDI), and the Swiss Spinal Stenosis (SSS) scores were collected in the form of questionnaires. Independent-samples t-tests, paired t-tests, Pearson's correlation analysis, and multiple regression analysis were applied for data analysis. To confirm the accuracy of the results of the multiple regression analysis, an additional 40 patients with LSS were included and assessed for model evaluation. The postoperative 6-minute walking distance (6MWD) increased significantly (mean 209.68 [SD 146.33] vs 399.42 [SD 66.15] m, p < 0.001) but remained lower than that of the control group (mean 460.30 [SD 54.60] m, p = 0.006). The SSS-Physical Function (SSS-PF), ODI, and BDI scores were strongly correlated with the preoperative 6MWD (r > 0.7). Among these scores, the SSS-PF score had the strongest correlation with the preoperative 6MWD in patients with LSS (r = -0.836, p < 0.001). Postoperative SSS-PF scores also demonstrated an excellent correlation with the 6MWD (r = -0.807). The preoperative dural sac area was significantly larger in patients with a 6MWD ≥ 100 m (mean 67.49 [SD 19.76] mm2) than in patients with a 6MWD < 100 m (56.65 [SD 7.80] mm2; p = 0.010). Walking ability can be effectively assessed by the SSS-PF, ODI, BDI, and JOA scale scores. The SSS-PF scale demonstrated an excellent correlation with 6MWD and showed promise as the best patient-reported assessment tool for walking ability in LSS, particularly in clinical settings where objective testing is not feasible.