Stitching path planning using circular needles-tissue interaction model

Flexible needle insertion is performed in many clinical and brachytherapy procedures. Needle bending which results from needle–tissue interaction and needle flexibility plays a pivotal role in implantation accuracy. In this paper, a needle insertion force model and a mechanics-based needle deflection model are applied in simulating the real needle insertion process. Using tissue-equivalent materials, the needle force model is acquired from needle insertion experiments. Based on the principle of minimum potential energy, a mechanics-based model is developed to calculate needle deflection. The needle deflection model incorporates needle insertion forces model, needle–tissue interaction model, needle geometric, and tissue properties. The bending–stretching coupling and geometric non-linearity of the flexible needle are both taken into consideration in the needle deflection model. A modified p–y curves method is first introduced in depicting the lateral needle–tissue interaction. The comparison between experimental and simulation results of needle deflection shows that our mechanics-based model can simulate the deflection of the flexible needle with reasonable accuracy. Parametric studies on different geometry properties of needles show that our mechanics-based model can precisely predict the needle deflection when more than one parameter is changed. In addition, as the needle deflection results are obtained numerically by Rayleigh–Ritz approach, further study on the form of deflection formulation leads to the conclusion that choosing a higher order polynomial can improve the overall simulation accuracy.

Download Full-text

A Novel Material Point Method Based Needle-Tissue Interaction Model

Volume 1: Additive Manufacturing; Manufacturing Equipment and Systems; Bio and Sustainable Manufacturing ◽

10.1115/msec2019-2953 ◽

2019 ◽

Author(s):

Murong Li ◽

Yong Lei

Keyword(s):

Material Point Method ◽

Interaction Model ◽

Needle Insertion ◽

Friction Model ◽

Material Point ◽

Contact Forces ◽

Point Method ◽

Virtual Surgery ◽

Tissue Interaction ◽

Novel Material

Abstract Needle-tissue interaction model plays an important role in virtual surgery training, pre-intervention planning and intra-intervention guidance. Traditionally, finite element methods (FEM) had been a primary and popular way for simulation modeling. However, FEM, as a mesh-based numerical calculations, is likely to encounter numerical difficulties due to mesh distortion as needle insertion process includes damage, fracture and penetration. In this work, a novel material point method (MPM) based needle-tissue interaction model is proposed, which combines the advantages of Lagrangian and Euler methods. A simplified contact algorithm and friction model are integrated to calculate contact forces as well as the resultant tissue deformations. Both preliminary contact forces and deformation results are compared with test experiments, which show that the maximum and mean displacement errors are 0.9768mm and 0.5134mm, respectively while the mean relative errors of force is 14%. This preliminary result demonstrates that MPM has great potential in needle-tissue interaction modeling.

Download Full-text