Biomechanical comparative evaluation of percutaneous fixations with vertebral expansion for vertebral compression fractures: an experimental and finite element study

This study uses in vitro experiments and validated finite element models (FEM) to analyze the effect of posterior fixation, alone or associated with expandable device (ED) and/or cement. 3-dimensional FEMs of intact, fractured and instrumented spine were built and compared with experimental load-displacement curves. FEM ranges of motion were within the experimental corridors. Stresses appeared sensitive to both implant configuration and fracture severity with a stress reduction up to 84%. The FEM highlighted that for a same instrumental strategy, different biomechanical performances were observed according to fracture severity. When bone continuity is altered, both ED and cement may be needed.