Techniques in in vitro spine biomechanics testing

In vitro experiments allow to determine biomechanical properties directly from real complex structures. Such studies are important for basic understanding of the healthy, degenerated or injured spine. These data are also necessary for validation or calibration of finite element models. But in vitro experiments should also be warranted for preclinical evaluation of new spinal surgeries without or with spinal implants to prove the safety and efficacy. Quasi-static in vitro flexibility measurements allow the comparison of the initial postoperative stability with the intact specimen and even allow the comparison of several surgical strategies or implants on the same specimens. Sometimes loads or deformations can be measured directly at the structures. Due to the complexity the loads that are simulated and other conditions may differ between research groups which makes comparison of similar experiments difficult. This presentation aims to summarize the possibilities and limitations of different testing devices and load applications.