Application of high-pushing-force NiTi for minimal access surgery

Abstract
High pushing force NiTi is a brand new material suitable for applications of medical guidewire. lt bas high stiffness, but it has no yield point, does not show superelastic plateau, and the residual strain after 4% strain is very small. High pushing force NiTi also shows stable characteristics at any temperature, i.e. its physical properties do not change according to the thermal environment conditions.

With its superior straightness, torque transmitting ability and pushability, it would be ideal to be used as guidewire in the colonoscopy. The mechanical properties have been tested at various temperatures. Video extensometer and digital image process have been applied to measure the strain accurately. For the design of colonoscope system, finite element method has been employed to identify the required quantitative parameters that can match the kink-resistance and pushing force characteristics.