Evaluation of effect of aneurysm model material on coil contact force and catheter movement

Abstract

To ensure safe coil embolization for cerebral aneurysms, it is important to investigate the contact force between a coil and an aneurysm wall. Therefore, in our previous study, we developed an experimental system for measuring the contact force between a coil and an aneurysm biomodel. However, because the aneurysm model was made of silicone rubber, its physical properties, such as the friction coefficient, differed from those of aneurysms in vivo. Therefore, in this study, we made an aneurysm model using poly (vinyl alcohol) hydrogel (PVA-H) and evaluated the effect of the model material on the contact force. In addition, we acquired images during the experiment and evaluated the behavior of the coil and catheter and the relationship between the catheter movement and the contact force. A commercially available coil was inserted through a catheter into two types of aneurysm models (silicone rubber and PVA-H), and the effects of the model material and the catheter tip position (near dome, at the center, and near neck) were evaluated. The contact force and the total movement of the catheter tip for the PVA-H model were smaller than those for the silicone rubber model. The contact force (total catheter movement) was greater (smaller) when the catheter tip was inserted deeper into the silicone rubber model. These results suggest that the state of contact between the aneurysm and the coil affects the contact force and the catheter movement and that these two values are related.

Methods for Evaluating Friction between Intravascular Device and Vascular Biomodel

“…Experiments using more complex vascular models made of silicone rubber [29,[35][36][37][38][39], acrylic [40], poly(vinyl alcohol) hydrogel [25][26][27][30][31][32][33], and elastomer-hydrogel skin multilayers [9,28] that mimic living tissue have also been conducted. 3D printers are widely used to prepare biomodels and can easily fabricate mold copies of the vascular tree, which is subsequently embedded in a liquid resin that solidifies into a solid biomodel.…”

“…Biomodels that mimic various types of vasculature [9,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] can be used to test new endovascular medical devices and teach techniques to medical personnel; they also allow the practice and planning of procedures before treatment without exposing patients to X-rays. Moreover, biomodels are more economical and ethical compared to human cadavers and animals.…”

Numerical simulation to evaluate guidewire and catheter behavior during catheter introduction

“…Comparison of the calculation and experimental results for validation of the simulation system showed that the trajectories and contact forces of the experimental and calculated medical devices tips had the same tendencies. Furthermore, this experimental apparatus can be used not only for validation of the numerical analyses but also as a simulation system that includes a mechanism to move a catheter, a guidewire, and a coil, and to reproduce the catheterization (Oishi et al, 2022;Takashima et al, 2021Takashima et al, , 2017Takashima et al, , 2014.…”