Dynamic Disc Designs

Does Forward Bending and Return Differ in Chronic LBP & Non-LBP People?

A very recent study 1 published in the ‘Journal of Biomechanics’ analyzed the dynamic interactions present between the human lumbar intervertebral motion segments during flexion and return. It wanted to help further understand the components linked to disability and pain.

What Was the Context?

Low back pain or LBP causes millions of people (around the globe) to experience physical, psychological, and economic stress. That’s why research continues to develop a more efficient means of LBP management.

Understanding of the biomechanics involved in back pain has increased due to continuous dynamic multi-segmental studies of the human lumbar motion. Such knowledge is required before attempting in vivo studies of loading during bending tasks.

However, the readings collected during bending tasks tend to be variable, and establishing normative values is challenging. That’s why, during bending tasks, there’s a need to further explore the interactions present between motion segments.

If one wants to model contemporaneous kinematics and loading for estimating relative intersegmental stresses occurring during bending motion, certain factors need to be studied. These factors include continuously measuring the proportions of the flexion as well as return motion that’s accepted by individual levels. The dynamic interactions between them, during bending, needs to be measured, too.

The current study set out to analyze the adjacent lumbar level’s motion contributions during flexion (active weight-bearing) and the return protocol while using quantitative fluoroscopy or QF.

Demonstrate flexion using LxH Dynamic Disc Model

What Was the Methodology?

The study involved a total of 8 patients (5 males and 3 females). Each of them had chronic non-specific LBP. An obvious mechanical disruption wasn’t present in the patients. All of them went through QF during the flexion as well as return motion. The patients were matched with 8 healthy controls. The same tasks had been performed by the controls, too.

The dynamic motion sharing of segments were calculated throughout the person’s bend and return. The segments were from L2 to S1.

Furthermore, the statistical analysis included the SPSS’s Shapiro Wilk test, independent t-tests, and the Mann-Whitney U.

What Was Concluded?

The results revealed that there were no significant differences between the groups with regards to age, weight, height, or BMI. However, the asymptomatic controls did show higher ranges of intervertebral motion with the only significant reading being at the L5-S1 level. The patient population showcased a significantly less range of motion at the L2-S1 level.

In simple terms, the results revealed that the patient and control groups displayed consistent yet non-significant differences in motion sharing patterns.

According to this study, the results could offer an advantage to help identify components that have a link to disability and pain. For example, this study shared that patients and controls have significant differences in their Average Motion Share or AvMS at the L3-L4 level. Take note; the IV-RoM data was unable to reveal these differences.

The said differences could be due to involuntary muscle activity, bending strategy, or passive tissue restraint.

Hopefully, the current data could help others conduct further research while also covering the muscle’s electrical activity, oxygenation, kinematics, and loading.