Systematic Review of Facet Tropism in the Lumbar Spine

Goal of the Study?

Facet tropism (asymmetrical orientation of the apophyseal joints greater than 7 degrees) is common in the lumbar spine. And because facet joints play a crucial role in stabilizing motion segments, alteration in their orientation can affect the dynamic motion and spinal position. In this research review1, these researchers searched keywords: facet, facet joint, lumbar disc, lumbar degenerative disc, degenerative lumbar spondylolisthesis, facet degeneration, lumbar disc herniation, degenerative spondylolisthesis and facet joint orientation. Moreover, the analysis included facet tropism and associated symmetry of the joint surfaces in these research papers.


Why are they doing this study?

The primary purpose of the study is to learn more about the facet orientation and its relationship to the searched keywords, and does this have any bearing on the general degenerative state of the lumbar spine?


What was done?

A total of 41 studies of 117 studies were included in the analysis. Facet joint angles were measured within these 41 studies and cross-referenced with disc degeneration, facet degeneration and degenerative spondylolisthesis of the lumbar spine.

Facet Tropism - Disc Bulge
Tropism of the inferior L5 in our Professional LxH Dynamic Disc Model.


What did they find?

Asymmetric facet surfaces were associated with degenerative lumbar disk along with degenerative lumbar spondylolisthesis. The authors point out that this often disregarded, common finding plays an important role in surgical interventions and facet blocks in clinical decision-making. 


Why do these findings matter?

There has been a recent trend in turning a blind eye away from abnormal anatomical findings. At Dynamic Disc Designs, we understand why this is the case. These pathoanatomical findings are often surgically chased down with costly and unsuccessful interventions in certain medical circles. However, an astute clinician will pay close attention to the relevant anatomy for that specific case and intervene surgically only when appropriate. Anatomical variants, like that of facet tropism, must play a role in the imbalance of motion to spinal motion segments. It is the skilled practitioner that knows the tissue relevance. The end-game spinal strategy should always be top of mind when managing cases. What will 80-90 years old look like for the patient? And can spinal stenosis be averted? 


At Dynamic Disc Designs, we use natural cadaveric specimens to construct our models. And in doing so, they often include facet tropism to help in the dynamic teachings of how this common finding can play a role in the motion complex of the lumbar spine.