There still seems to be some controversy when it comes to addressing the relationship between biomechanical instability and the degenerative changes in the lumbar spine in CLBP (chronic lower back pain) patients. A study 1 decided to gather more data about it.
Why such a focus?
Chronic low back pain or CLBP may be caused by the biomechanical instability following degenerative changes in the lumbar spine. Low back pain is experienced by millions of people around the globe. The course of clinical treatment for such an issue can be guided through radiographical assessment. Such an assessment would be of the bending motions of the lumbar spine as it might aid with the identification of the absence or presence of biomechanical instability in patients with CLBP.
Due to the said controversy, this study decided to look into the relationship between biomechanical instability and degree of degenerative changes in the lumbar spine in CLBP patients. Being a retrospective radiographical study, it focused on evaluating the changes in kinematics at various lumbar levels (the L5-S1 level, in particular) with progressive grades of disc degeneration as well as facet joint osteoarthritis in CLBP patients.
The current study involved 72 (51 males and 21 females) consecutive CLBP patients. The age range of the participants was kept 18 to 70 years.
It used standing neutral and dynamic flexion/extension (Fx/Ex) radiographs of the lumbar spine to evaluate the in vivo segmental kinematics at the L1-L2 through L5-L1. Changes in signal intensity and central disc height on mid-sagittal T2-weight MR (magnetic resonance) scans were used to quantify disc degeneration.
What were the Results?
The study shared that disc degeneration and facet joint osteoarthritis was able to occur independently of each other at the L5-L1 level. However, an association was observed at the L4-L5 as well as the L3-L4 levels. A greater range of motion in Ex and a smaller range of motion in Fx was observed in the absence of facet joint osteoarthritis (when compared to the upper lumbar levels). No change in the L5-L1 kinematics was observed with progressive disc degeneration in the absence of facet joint osteoarthritis. However, in the presence of such osteoarthritis, re-stabilization of the L5-L1 segment was observed between the severe and mild disc degeneration states.
The study concluded that unique degenerative and kinematic characteristics were exhibited by the L5-S1 motion segment compared with the upper lumbar motion segments. Furthermore, at the L5-S1 level, facet joint osteoarthritis and disc degeneration occurred independently of each other. The L5-S1 motion segment was biomechanically re-stabilized by severe disc degeneration if facet joint osteoarthritis was present.
What does it mean?
The study shared that the L5-S1 level, due to having unique anatomical features, may play a significant role in re-stabilizing the level with severe degeneration of the disc and facet joints. The data will prove beneficial in understanding more about CLBP and its clinical treatments.