loading

Goal of the Study?

In this preliminary study, 1 the authors compared the effects of loading compression and traction on lumbar disc measurements, particularly the magnitude and distribution pattern of fluid within lumbar discs, in relation to intervertebral disc degeneration.

 

Why are they doing this study?

Intervertebral disc degeneration (IVDD) is associated with many biochemical and morphological changes in the disc that contribute to degeneration and negatively impact normal function. With degeneration, there are changes to the amount of fluid and the distribution pattern of this fluid within the disc. The authors argue that this may provide unique biomarkers that can help with diagnosing and classifying degeneration. The authors hypothesize that using T2- weighted MR images will enable better insight into disc degeneration. It only changes in response to variations in fluid distribution and these potential degeneration biomarkers. 

 

What was done?

A total of 35 volunteers between the ages of 18-65 were recruited: 20 with and 15 without low back pain (LBP). Using a custom MRI compatible loading table, the participants spent 20 minutes in the supine, unloaded position; then they spent 20 minutes loaded in axial compression and then 20 minutes with axial traction. A compressive load equal to 50% of each subjects’ body weight was applied to simulate loading and traction. For lumbar discs, the height, angle, width, mean-T2 and T2 weighted centroid (T2WC) locations were calculated. Disc degeneration was measured using the 5-point scale by Pfirrmann et al.

 

What did they find?

Most of the effect size (ES) differences the authors found in response to loading were seen from compression to traction. They observed small but statistically significant changes with an inferior and posterior shift in L4-5 (ES: 0.4, 0.14) and L5-S1 (ES: 0.25, 0.33) T2 weighted centroid. More degeneration was associated with larger anterior displacement and more superior displacement of the disc T2WC. Moreover, degeneration was not associated with changes in disc width, but with greater degeneration, there were larger decreases in an extension of segmental angles.

From unloaded to compression, they found statistically significant small posterior shifts for the disc T2WC at the L1-2 level (ES: 0.39). They also saw an increase in L5-S1 width (ES: 0.22), an anterior shift in L1-2 T2WC (ES: 0.39), and L3-4 (mean 2.1˚) and L4-5 (1.8˚) extension angle. Additionally, with more degeneration, there were larger inferior movements of the disc T2WC, but not changes in disc width. 

Overall, their findings on compression to traction demonstrated the most significant findings in the lower lumbar levels. They also found a magnitude difference associated with the severity of disc degeneration. This supported their hypothesis that fluid distribution-related measurements illustrating the effects of degeneration and lumbar disc loading.

 

Why do these findings matter?

Biomarkers can help to illustrate how the lumbar spine responds to different loading conditions and can be used to monitor degenerative changes in the lumbar spine.

 


At Dynamic Disc Designs, we appreciate the dynamics of the discs and how professionals can communicate these small changes to patients as it relates to their dynamic symptoms and the solutions of back pain.

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