Computer simulation programs provide researchers with cost-effective methodologies for studying internal stresses and loads on biological specimens. Previous researchers have studied the mechanisms required to traumatically induce a disc herniation in cadaveric spines. However, there are no known studies that utilize computer simulation programs to study the mechanisms of disc herniation in the spine. Therefore, engineers at Explico have developed a three-dimensional finite element model of the lumbar spine with the purpose of predicting disc herniation mechanics.
A three-dimensional finite element model of the lumbar spine was built based on CT scan data of a cadaveric specimen. The model was validated under a variety of conditions to ensure the models biofidelity. The validated model was altered so that the boundary conditions mimicked the boundary conditions performed by previous researchers on cadaveric specimens. The model was loaded under varying amounts and combinations of compression and flexion. Disc stresses and loads most consistent with herniation risk were evaluated. We hypothesized that the disc would experience the greatest magnitudes of nucleus extrusion force and posterior annulus stress when the model was exposed to a combination of compression and flexion.
Results of the study confirmed our hypothesis and demonstrated that Explico’s model accurately predicted the greatest disc herniation risk under loading mechanisms consistent with the scientific literature. Specifically, the disc experienced the greatest magnitudes of nuclear extrusion force and posterior annular stress when the model was loaded with high compression while in its most flexed position. Development and validation of a finite element model that accurately predicts disc herniation mechanics provides Explico’s engineers the tools to further evaluate disc herniation mechanism amongst a variety of conditions.
