In Vitro Experimental Studies and Numerical Modeling to Investigate the Biomechanical Effects of Surgical...

This paper offers a comprehensive systematic review of biomechanical research on the spine and on in vitro and numerical methods of investigation. This review focuses on interventions on the ligaments, on the facets, and on the lamina (facetectomies, laminectomies, and laminoplasties). Surgical interventions on the facets and lamina in some cases yield dissatisfactory clinical follow-up. Patient outcome is strongly related to the effects that such interventions have on the biomechanical functionality of the spine. The papers examined include those addressing the untreated spine (range of motion and stiffness), but the focus is on experimental and numerical investigations studying the role of the ligaments and of the posterior structures (including their role in granting spine stability and the biomechanical behavior of each ligament). The papers were classified based on the different investigation approaches. In vitro experiments exploit dedicated biomechanical spine testers to measure the mechanical properties of physical specimens. Numerical modeling (multibody dynamics, finite-element analysis) allows predicting the effect of different conditions. All the papers indicate that interventions on the ligaments, facets, and lamina increase range of motion and decrease stability. The quantitative results show great variability across studies. This review shows how it is possible to use in vitro and numerical methods to investigate the biomechanical effects of surgical interventions.