[Effect of clamping tensile strength on load distribution in paired mounted spinal internal fixators]

Paired internal spinal fixation devices are not necessarily loaded symmetrically when the vertebrae are unable to support one another directly. A finite element model has been developed to predict the influence of clamping rigidity on the load distribution. If the stiffness of one clamping element is significantly reduced, the corresponding implant will bear only about 30 percent of the outer bending moment. The theoretical results were confirmed experimentally with sensor-loaded internal spinal fixation devices.