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Updated: Apr 25, 2026

A Coupled Experiment-finite Element Modeling Methodology for Assessing High Strain Rate Mechanical Response of Soft Biomaterials
Published on: May 18, 2015
Monolithic superelastic rods with variable flexural stiffness for spinal fusion: modeling of the
Yann Facchinello1, Vladimir Brailovski1, Yvan Petit1
1École de technologie supérieure, 1100 Notre-Dame Street West, Montreal, QC, Canada H3C 1K3; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400, boul. Gouin West, Montreal, QC, Canada H4J 1C5.
Abstract:
The concept of a monolithic Ti-Ni spinal rod with variable flexural stiffness is proposed to reduce the risks associated with spinal fusion. The variable stiffness is conferred to the rod using the Joule-heating local annealing technique. The annealing temperature and the mechanical properties' distributions resulted from this thermal treatment are numerically modeled and experimentally measured. To illustrate the possible applications of such a modeling approach, two case studies are presented: (a) optimization of the Joule-heating strategy to reduce annealing time, and (b) modulation of the rod's overall flexural stiffness using partial annealing. A numerical model of a human spine coupled with the model of the variable flexural stiffness spinal rod developed in this work can ultimately be used to maximize the stabilization capability of spinal instrumentation, while simultaneously decreasing the risks associated with spinal fusion.
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