Spinal fixation systems provide surgical versatility, but the complexity of their design may reduce their strength and fatigue resistance. There is no published data on the mechanical properties of such screws. Screws were assembled according to a ver...
Spinal fixation systems provide surgical versatility, but the complexity of their design may reduce their strength and fatigue resistance. There is no published data on the mechanical properties of such screws. Screws were assembled according to a vertebrectomy model for destructive mechanical testing. Group of two assemblies were tested in static compression. One had been finished the surface by grit blast treatment, the other had been finished the surface by bead blast. Modes of failure, yield, and ultimate strength, yield stiffness, and cycles to failure were determined for six assembles. Static compression 2% offset yield loads ranges from 327 to 419N. Fatigue loads were determined two level, 50% and 75% of the average load from static compression yield load. The assembly of bead blast treatment only achieved 5 million cycles at 275N in compression bending.