Modeling and Simulation of Flexible Needle Insertion Into Soft Tissue Using Modified Local Constraint Method

2014 ◽  
Author(s):  
Yong Lei ◽  
Bin Lian
Keyword(s):  
Soft Tissue ◽  
Axial Force ◽  
Equilibrium Position ◽  
Radial Direction ◽  
Needle Insertion ◽  
Radial Force ◽  
Spring Model ◽  
Local Constraint ◽  
Nodal Points ◽  
Constraint Method

This paper presents a new simulation model for flexible needle insertion into soft tissue using modified local constraint method. In this work, we assume deformation of the needle is relatively small, therefore, the soft tissue deformation in the radial direction is far less than it is in the axial direction. Under the assumptions above, the spring model in the radial direction of the needle is established and applied in the puncture procedure to obtain the equilibrium position of the needle-tissue system. The FEM model for the simulation includes three iterative steps: 1. Distribute the axial force on the needle into tissue nodes, and add radial constraint on tissue nodes that are connected with needle’s shaft, then calculate the whole displacement of the tissue nodes; 2. Based on the whole displacement of all nodal points and the effective stiffness matrix, we get the radial force on the tissue, then we use the spring model in the radial direction to get the equilibrium position; 3. Compound the radial and axial force on the tissue nodal points to obtain the actual displacement. Simulation results are presented and discussed.

Simulation for Needle Deflection and Soft Tissue Deformation in Needle Insertion

2010 ◽  
Vol 139-141 ◽  
pp. 889-892
Author(s):  
De Dong Gao ◽  
Hao Jun Zheng
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Three Dimensional ◽  
Needle Insertion ◽  
Tissue Deformation ◽  
Spring Model ◽  
Ansys Software ◽  
Soft Tissue Deformation ◽  
Needle Deflection ◽  
Element Method

Needle deflection and soft tissue deformation are the most important factors that affect accuracy in needle insertion. Based on the quasi-static thinking and needle forces, an improved virtual spring model and a finite element method are presented to analyze needle deflection and soft tissue deformation when a needle is inserted into soft tissue. According to the spring model, the trajectory of the needle tip is calculated with MATLAB using different parameters. With the superposed element method, the two and three dimensional quasi-static finite element models are created to simulate the dynamic process of soft tissue deformation using ANSYS software. The two methods will be available for steering the flexible needle to hit the target and avoid the obstacles precisely in the robot-assisted needle insertion.

Mechanics-Based Interactive Modeling for Medical Flexible Needle Insertion in Consideration of Nonlinear Factors

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Shan Jiang ◽  
Xingji Wang
Keyword(s):  
Soft Tissue ◽  
Kinematic Model ◽  
Needle Insertion ◽  
Winkler Foundation ◽  
Nonlinear Characteristics ◽  
Deformation Control ◽  
Needle Deflection ◽  
Iteration Cycle ◽  
Foundation Model ◽  
Sensitivity Studies

A mechanics-based model of flexible needle insertion into soft tissue is presented in this paper. Different from the existing kinematic model, a new model has been established based on the quasi-static principle, which also incorporates the dynamics of needle motions. In order to increase the accuracy of the model, nonlinear characteristics of the flexible needle and the soft tissue are both taken into account. The nonlinear Winkler foundation model and the modified Euler–Bernoulli theory are applied in this study, providing a theoretical framework to study insertion and deformation of needles. Galerkin method and iteration cycle analysis are applied in solving a series of deformation control equations to obtain the needle deflection. The parameters used in the mechanics-based model are obtained from the needle force and needle insertion experiment. Sensitivity studies show that the model can respond reasonably to changes in response to variations in different parameters. A 50 mm needle insertion simulation and a 50 mm corresponding needle insertion experiment are conducted to prove the validity of the model. At last, a study on different needle tip bevel demonstrates that the mechanics-based model can precisely predict the needle deflection when more than one parameter is changed. The solution can also be used in optimizing trajectory of the needle tip, enabling the needle to reach the target without touching important physiological structures such as blood vessels with the help of dynamic trajectory planning.

scholarly journals Effect of time complexities and variation of mass spring model parameters on surgical simulation

2014 ◽  
Vol 9 (4) ◽  
Author(s):  
Salina Sulaiman ◽  
Tan Sing Yee ◽  
Abdullah Bade
Keyword(s):  
Soft Tissue ◽  
Human Liver ◽  
Soft Tissues ◽  
Surgical Simulation ◽  
Model Parameters ◽  
Spring Model ◽  
Surgical Simulator ◽  
Tissue Model ◽  
Mass Spring Model ◽  
Mass Spring

Physically based models assimilate organ-specific material properties, thus they are suitable in developing a surgical simulation. This study uses mass spring model (MSM) to represent the human liver because MSM is a discrete model that is potentially more realistic than the finite element model (FEM). For a high-end computer aided medical technology such as the surgical simulator, the most important issues are to fulfil the basic requirement of a surgical simulator. Novice and experienced surgeons use surgical simulator for surgery training and planning. Therefore, surgical simulation must provide a realistic and fast responding virtual environment. This study focuses on fulfilling the time complexity and realistic of the surgical simulator. In order to have a fast responding simulation, the choice of numerical integration method is crucial. This study shows that MATLAB ode45 is the fastest method compared to 2nd ordered Euler, MATLAB ode113, MATLAB ode23s and MATLAB ode23t. However, the major issue is human liver consists of soft tissues. In modelling a soft tissue model, we need to understand the mechanical response of soft tissues to surgical manipulation. Any interaction between haptic device and the liver model may causes large deformation and topology change in the soft tissue model. Thus, this study investigates and presents the effect of varying mass, damping, stiffness coefficient on the nonlinear liver mass spring model. MATLAB performs and shows simulation results for each of the experiment. Additionally, the observed optimal dataset of liver behaviour is applied in SOFA (Simulation Open Framework Architecture) to visualize the major effect.

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