Needle Insertion Force Model for Haptic Simulation

Author(s):  
Adam Gordon ◽  
Inki Kim ◽  
Andrew C. Barnett ◽  
Jason Z. Moore

Percutaneous medical procedures rely upon clinicians performing precise needle insertion in soft tissue. The utility of haptic simulation systems in training clinicians for these procedures is highly dependent upon the ability to render accurate insertion force feedback. This paper presents a piecewise mathematical model for insertion force that does not require tissue material properties, detailed mechanical approximations, or complex computations. With manipulation of model parameters, a wide variety of insertion tasks and clinical scenarios can be modeled. Through needle insertion experiments and parameter estimation, this model was demonstrated to replicate the insertion forces associated with a variety of needle and tissue types. In 11 of 12 needle and tissue combinations tested, the model replicated the insertion force with an average absolute mean error of less than 0.065 N.

2014 ◽  
Vol 14 (05) ◽  
pp. 1450076 ◽  
Author(s):  
SHAN JIANG ◽  
XINGJI WANG ◽  
ZHILIANG SU

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.


2014 ◽  
Vol 8 (2) ◽  
Author(s):  
Yancheng Wang ◽  
Bruce L. Tai ◽  
Hongwei Yu ◽  
Albert J. Shih

Silicone-based tissue-mimicking phantom is widely used as a surrogate of tissue for clinical simulators, allowing clinicians to practice medical procedures and researchers to study the performance of medical devices. This study investigates using the mineral oil in room-temperature vulcanizing silicone to create the desired mechanical properties and needle insertion characteristics of a tissue-mimicking phantom. Silicone samples mixed with 0, 20, 30, and 40 wt. % mineral oil were fabricated for indentation and needle insertion tests and compared to four types of porcine tissues (liver, muscle with the fiber perpendicular or parallel to the needle, and fat). The results demonstrated that the elastic modulus and needle insertion force of the phantom both decrease with an increasing concentration of mineral oil. Use of the mineral oil in silicone could effectively tailor the elastic modulus and needle insertion force to mimic the soft tissue. The silicone mixed with 40 wt. % mineral oil was found to be the best tissue-mimicking phantom and can be utilized for needle-based medical procedures.


Author(s):  
Andrew C. Barnett ◽  
Yuan-Shin Lee ◽  
Jason Z. Moore

This work develops a needle insertion force model based on fracture mechanics, which incorporates the fracture toughness, shear modulus, and friction force of the needle and tissue. Ex vivo tissue experiments were performed to determine these mechanical tissue properties. A double insertion of the needle into the tissue was utilized to determine the fracture toughness. The shear modulus was found by applying an Ogden fit to the stress–strain curve of the tissue achieved through tension experiments. The frictional force was measured by inserting the needle through precut tissue. Results show that the force model predicts within 0.2 N of experimental needle insertion force and the fracture toughness is primarily affected by the needle diameter and needle edge geometry. On average, the tearing force was found to account for 61% of the total insertion force, the spreading force to account for 18%, and the friction force to account for the remaining 21%.


Author(s):  
David Pepley ◽  
Mary Yovanoff ◽  
Katelin Mirkin ◽  
Scarlett Miller ◽  
David Han ◽  
...  

Medical simulation plays a critical role in the training of surgical and medical residents. Training simulators give residents an environment to practice a wide variety of procedures where they can learn and make mistakes without harming a living patient [1]. In recent years, much research has been conducted on applying haptic or force feedback technology to surgical simulators in order to create more effective training devices [2]. Simulators such as the LapSim (laparoscopic simulator) and the PalpSim (palpitation needle insertion simulator) have both utilized haptic feedback arms to provide the physical sensation of performing surgical procedures to the user [3, 4]. The haptic simulator shown in Fig. 1 is currently in development. This virtual reality haptic robotic simulator for central venous catheterization (CVC) utilizes a haptic feedback arm to provide the feeling of a syringe being inserted into neck tissue [5]. Currently, there is little experimental data relating needle force to depth. To determine the forces necessary to program into the haptic robotic device, a force sensing syringe was developed and cadaver experiments were performed. This paper presents the development of a syringe which can accurately measure needle insertion force and the proceeding experiments conducted using this device on a fresh frozen cadaver. The results of these cadaver needle insertions are characterized into force profiles for needle insertion force that are implemented into the haptic based CVC simulator.


Author(s):  
Guobiao Ji ◽  
Liang Cheng ◽  
Shaohua Fei ◽  
Jiangxiong Li ◽  
Yinglin Ke

Through-thickness reinforcement is a promising solution to the problem of delamination susceptibility in laminated composites. Modeling Z-pin–prepreg interaction is essential for accurate robotics-assisted Z-pin insertion. In this paper, a novel Z-pin insertion force model combining the classical cohesive finite element (FE) method with a dynamic analytical fracture mechanics model is proposed. The velocity-dependent cohesive elements, in which the fracture toughness is provided by the analytical model, are implemented in Z-pin insertion FE model to predict the crack initiation and propagation. Then Z-pin insertion experiments are performed on prepreg sample with metallic Z-pins at different velocities to identify the analytical model parameters and validate the simulation predictions offered by the model. Dynamics of Z-pin interaction with inhomogeneous prepreg is described and the effects of insertion velocity on prepreg contact force are studied. Results show that the force model agrees well with experiments and the fracture toughness rises with the increasing Z-pin insertion velocity.


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