The effect of instrumentation with different mechanical properties on the pig spine during growth

The effect off mechanically altered bone on spinal growth using instrumentations with different mechanical properties is quantified through the use of experimental tests. Eight spine segments from three female pigs weighing 60 90 lb were subjected to a continuous tensile force. The load (0 - 400 N) was applied using a MTS Alliance RT/50 machine and the resulting extension recorded using an extensometer. Displacements between the screws were measured in control without implant, metal plate system, and spring system, respectively. It is shown that the addition of an implant will increase the stiffness of the spine, which will affect the extension of the spine and hence hinder growth in the spine.