Nickel-Titanium self-knotting suture wire for deep surgical field: a validated numerical model

The aim of this work is to set a finite element model of a Ni-Ti self-knotting suture, designed for deep neurosurgical applications, and to provide a reliable tool for evaluating its functionality before entering in the clinical practice. A close shape is memorized through specific heat treatments; once implanted in the open configuration the surgeon does not need to pack any knot since the suture is closing by itself only using some drops of physiological solution. A material user-subroutine allows the modeling of the shape memory effect which governs its functionality. Simple experiments involving shape-recovery behavior are designed to validate the model. The numerical approach is then finalized at giving a better insight into the device performance under different working conditions. Finite element tools demonstrate being an optimal choice for ameliorating the device design to achieve the desired mechanical response.