A response surface-based approach to predict spinal rod contouring parameters

Rod contouring can be intraoperatively performed by surgeons to obtain bent spinal rods that better fit the physiological curvature of the spine. However, this procedure exploits the material plastic deformation, which is known to affect fatigue behavior in vivo. Numerical models allow the assessment of the residual stress field due to contouring, but at a high computational cost, which is not compatible with the extensive use of in silico models in preoperative clinical planning. For this reason, after preparing a finite element analysis of titanium rod contouring, a response surface-based approach is proposed to correlate contouring-related parameters with residual stress field and rod curvature.