Experiment study on puncture force between MIS suture needle and soft tissue

摘要

In this paper, the interactive action between minimally invasive surgical suture needle and soft tissue was investigated under different insertion velocities, needle geometries, insertion angles and tissue characteristics to simulate the real surgical suture needle-tissue operation conditions. Experimental results demonstrated that the process of insertion was divided into two phases: no break phase and break phase. The puncture force generated at the mutation point where the tissue surface was breached. The puncture force and time for the first puncture significantly decreased with the increasing insertion velocity. The needle with triangle cross-section tip and larger size showed higher puncture force than that with round cross-section and smaller one. The penetration force reduced evidently with the advancing insertion angle, and it reached the lowest value when the angle is 90°. Moreover, an empirical single-parameter model of third-degree polynomial could predict the stiffness when a suture needle inserted into a complex soft tissue and showed a good fit to the experiment data. The results would provide reliable and significant mechanical database for the design of force feedback system in the surgical suture, either in endoscopic surgery or robotic suturing.