<p>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 <i>in vivo</i>. 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.</p> <div style="text-align:center;"> </div>

Keywords

Endovascular treatment, Cerebral aneurysm, Coil embolization, Contact force, Catheter, Phantom, First coil

Paper information

[Advance Publication] (Proper information for citation will be announced after formal publication)

Various catheter simulators using a computer or blood vessel biomodels have been developed for training of medical students and young physicians. Moreover, we have developed a system to simulate a guidewire in blood vessels that uses both numerical analysis and experimental observation for the quantitative analysis of treatment technique, surgical planning, intra-operative assistance, and to facilitate the design of new guidewires. However, not limited to our group, there is a lack of studies evaluating the motions of both the guidewire and catheter and their interaction in a blood vessel. Therefore, in the present study, we modified our computer-based system and experimental apparatus to evaluate the catheter motion and compared both results. First, we added a mechanism to the experimental apparatus to move and evaluate the catheter in a poly (vinyl alcohol) hydrogel blood vessel model. Second, we added a new catheter model to the calculation. We subsequently evaluated the behaviors of the medical devices (the guidewire and the catheter) by measuring the three-dimensional position and the contact force between the medical devices and the vessel wall. Comparison of the calculation and experimental results showed that the trajectories and the contact forces of both the experimental and numerically analyzed medical devices had the same tendencies. By considering the flexibility of the catheter in both the experimental and numerical analysis methods, we could reproduce the phenomena seen in clinical situations, such as movement of the catheter during the insertion or removal of the guidewire, and movement of the guidewire during the insertion of the catheter.

Keywords

Endovascular treatment, Simulation, Guidewire, Catheter, Phantom, Numerical analysis

Paper information

Kazuto TAKASHIMA, Atomu OIKE, Kiyoshi YOSHINAKA, Kaihong YU, Makoto OHTA, Koji MORI, Naoki TOMA, “Evaluation of the effect of catheter on the guidewire motion in a blood vessel model by physical and numerical simulations”, Journal of Biomechanical Science and Engineering, Vol.12, No.4 (2017), p.17-00181. doi:10.1299/jbse.17-00181. Final Version Released on September 15, 2017, Advance Publication Released on August 10, 2017.

Vascular diseases, such as ischemic heart disease, infarction, aneurysms, stroke and stenosis are a leading cause of serious long-term disability and their mortality rate is as high as that of cancers in many countries. Recently, neurovascular intervention using catheters is a minimally-invasive endovascular technique used to treat vascular disease of the brain, and a navigation system for catheters has been developed to facilitate surgical planning and to provide intra-operative assistance. Since the mechanical properties of a catheter play an important role in reaching the targeted disease, tracking of catheter movement during endovascular treatment may be useful to increase confirmation of the rate of successful operation. In this study, we developed an in vitro tracking system for catheter motion using poly (vinyl alcohol) hydrogel (PVA-H) to mimic an arterial wall. The employed models were made of PVA-H, which is sufficiently transparent to permit observation of catheter movement in the artery. This system is expected to contribute to validation of computer-based navigation systems for surgical assistance.

Keywords

Endovascular Treatment, Catheter Motion, Tracking System, Poly (vinyl alcohol) Hydrogel, Biomodel

Paper information

ChangHo YU, Hiroyuki KOSUKEGAWA, Keisuke MAMADA, Kanju KUROKI, Kazuto TAKASHIMA, Kiyoshi YOSHINAKA and Makoto OHTA, “Development of an In Vitro Tracking System with Poly (vinyl alcohol) Hydrogel for Catheter Motion”, Journal of Biomechanical Science and Engineering, Vol. 5, No. 1 (2010), pp.11-17 . doi:10.1299/jbse.5.11