Residual Stresses in Titanium Spinal Rods: Effects of Two Contouring Methods and Material Plastic Properties

This study aims at investigating two rod contouring strategies, French bender (FB) contouring (clinical gold standard), and uniform contouring, through validated FE models. A careful characterization of the elastoplastic material response of commercial implants is led. Compared to uniform contouring, FB induces highly localized plasticizations in compression under the contouring pin with extensive lateral sections undergoing tensile residual stresses. The sensitivity analysis highlighted that the assumed postyielding properties significantly affect the numerical predictions; therefore, an accurate material characterization is recommended.
Source: Journal of Biomechanical Engineering - Category: Biomedical Engineering Source Type: research