Gait analysis does not correlate with clinical and MR imaging parameters in patients with symptomatic lumbar spinal stenosis

BACKGROUND: Parameters of MR imaging play a pivotal role in diagnosing lumbar spinal stenosis (LSS), and serve as an important tool in clinical decision-making. Despite the importance of MR imaging, little is known about the correlation between MRI parameters, objective gait analysis, and clinical presentation of patients with lumbar spinal stenosis. METHODS: Sixty-three patients from our clinic with symptomatic lumbar spinal stenosis leading to neurogenic claudication were included in this study in accordance with clearly defined inclusion and exclusion criteria. Clinical parameters, the depression status (CES-D), the subjective functional back capacity (FFbH-R), and the absolute walking distance (treadmill gait analysis) were quantitatively evaluated in correlation with morphological data from radiographs and MRI scans, in order to determine the coherence of spinal canal narrowing and clinical affliction. RESULTS: Sixty-three consecutive paents with a median age of 68 years and a mean Body Mass Index (BMI) of 28 were included in the study. The mean FFbH-R score displayed a value of 44 percent. The depression status scored an average of 13.6. Objectively measured walking distances showed a mean value of 172 m until patients stopped due to leg pain. A significant difference was found between the objectively measured and the subjectively estimated walking distance. The mean cross-sectional area of the dural tube at L1/2 was 113 mm(2), at L2/3 94 mm(2), at L3/4 73 mm(2), at L4/5 65 mm(2), and at L5/S1 93 mm(2). The mean overall cross sectional area of the dural tube of all segments did not correlate with the objectively measured walking distance. However, bivariate analysis found that the BMI (tau b = -0.194), functional back capacity (tau b = -0.225), and the cross sectional area of the dural tube at L1/2 (tau b = -0.188) correlated significantly with the objectively measured walking distance. CONCLUSION: According to the results of this study MRI findings failed to show a major clinical relevance when evaluating the walking distance in patients with lumbar spinal stenosis and, therefore, should be treated with some caution as a predictor of walking distance. In determining the disease pattern of spinal stenosis functional back capacity and BMI might play a more active role than previously thought.