The Study: Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling.
a. More information is needed concerning the ways that “spinopelvic alignment effects spinal load distribution.”
b. The authors felt that musculoskeletal modeling might help shed light on the associations of spinal alignment to conditions such as lower back pain, disc herniation etc.
c. The authors used the “AnyBody full-body musculoskeletal model”.
d. The body model is based on an average European male.
e. They simulated postures in the standing position.
f. They set up 2772 different configurations.
g. The authors note a number of limitations in the study, for example: “The stiffness of the intervertebral discs was neglected. The facet joints are not modelled in the default AnyBody model. Nevertheless, they are not expected to have an impact on the loads at the motion segment in the upright position, but rather on the load sharing among the different structures in each motion segment, which is beyond the scope of the present work.”
h. Additionally the thoracic area is represented as a single segment along with other limitations, but this is still a complex model.
i. They state, “In conclusion, our findings indicate that changes in global sagittal alignment, lumbar typology, and sacral inclination, but not in pelvic incidence, can affect intervertebral loads in the lumbar spine and spinal muscle activation.” (emphasis ours)
j. They further state, “Accounting for these variations would be advantageous for clinical evaluation, owing to the relation between altered loads and the risk of disc herniation, vertebral fracture, anterior displacement, and low back pain as well.”
Changes in postural alignment can affect lumbar loads and accounting for these variations is useful to the clinician as there is a relation of altered loads to spinal problems.
This is a very complex article that can be boiled down to the simple concept that altered spinal alignment (posture) is a bad thing for spinal loading. ( How’s that for oversimplification!) . So once again we see that there is much more to spinal health than just freeing up spinal motion with manipulation. Structural alignment actually matters.
As I have frequently tried to explain, modeling is a method to understand problems that are difficult or impossible to understand in their full complexity. Models are not the real thing and as such they can be looked at as a more simplified example of the real thing and therefore easier to study. But, we can learn a lot from modeling and this one is quite inclusive in scope. I encourage readers to look at the whole paper. and remember, once again we see that structure is important. I would like to thank the authors from the IRCCS Istituto Ortopedico Galeazzi in Milan, Italy.
Reviewer: Roger Coleman DC
Editor’s Comments: So spinal alignment actually matters eh? Hmmm…who would’ve thought.
Editor: Mark R. Payne DC
Reference: Bassani T, Casaroli G, Galbusera F. Dependence of lumbar loads on spinopelvic sagittal alignment: An evaluation based on musculoskeletal modeling. PLoS One 2019 Mar 18;14(3):e0207997. doi: 10.1371/journal.pone.0207997. eCollection 2019.
Link to Abstract: https://www.ncbi.nlm.nih.gov/pubmed/30883563