Kinetic magnetic resonance imaging analysis of lumbar segmental mobility in patients without significant spondylosis

Purpose: The purpose of this study was to examine lumbar segmental mobility using kinetic magnetic resonance imaging (MRI) in patients with minimal lumbar spondylosis. Methods: Mid-sagittal images of patients who underwent weight-bearing, multi-position kinetic MRI for symptomatic low back pain or radiculopathy were reviewed. Only patients with a Pfirrmann grade of I or II, indicating minimal disc disease, in all lumbar discs from L1-2 to L5-S1 were included for further analysis. Translational and angular motion was measured at each motion segment. Results: The mean translational motion of the lumbar spine at each level was 1.38 mm at L1-L2, 1.41 mm at L2-L3, 1.14 mm at L3-L4, 1.10 mm at L4-L5 and 1.01 mm at L5-S1. Translational motion at L1-L2 and L2-L3 was significantly greater than L3-4, L4-L5 and L5-S1 levels (P < 0.007). The mean angular motion at each level was 7.34 at L1-L2, 8.56 at L2-L3, 8.34 at L3-L4, 8.87 at L4-L5, and 5.87 at L5-S1. The L5-S1 segment had significantly less angular motion when compared to all other levels (P < 0.006). The mean percentage contribution of each level to the total angular mobility of the lumbar spine was highest at L2-L3 (22.45 %) and least at L5/S1 (14.71 %) (P < 0.001). Conclusion: In the current study, we evaluated lumbar segmental mobility in patients without significant degenerative disc disease and found that translational motion was greatest in the proximal lumbar levels whereas angular motion was similar in the mid-lumbar levels but decreased at L1-L2 and L5-S1.