4.1. Application examples implant design

The possibility of using the biomechanical simulation in the area of spinal surgery is diverse. Preoperatively, the effects of mono- or multisegmental spinal fusion on adjacent segments can be analyzed. In addition, an optimized positioning of the inserted implant can be demonstrated by taking into account the reconstruction of the sagittal balance or an adequate stress distribution. One can also compare the effects of minimally invasive surgical methods to surgical procedures with high degree of resections of spinal structures.

Although most manufacturers of implants offer different sizes of implants, a full-area contact of the implant with the vertebral body is not always ensured. An insufficient anchorage can lead to local stress peaks at the contact points. With the help of computer-assisted simulations, such stress peaks can be analyzed. To ensure the best possible anchoring, the effects of different contact surface designs of the implant can be determined. Thus, the simulation can contribute to a development of patient-specific shaped implant surfaces, which ensure a permanent fit of the implant without sinking and slipping. Preoperatively, the effects of different implant lengths can also be analyzed.

The following simulations are intended as examples for a patient-specific problem and do not include the entire "expanded process chain," but only the subsection of the "biomechanical simulation." Thus, the following examples serve to illustrate the added value by the biomechanical modeling with regard to operation planning.
