Int J Appl Electromagn Mech.2013 41(1):87-96.

Design and development of hinge-type microstirrer for thrombus dissolution.

Minoru Morita1, Zongwei Jiang1, Kazunori Yamamoto1, Michiyasu Suzuki2

1Department of Mechanical Engineering, Yamaguchi University, Yamaguchi, Japan 2Department of Neurosurgery, School of Medicine, Yamaguchi University, Yamaguchi, Japan


Abstract

Cerebral strokes occur on account of a thrombus formed in blood vessels, which blocks the blood flow to the brain and induces brain cell necrosis. We require the ability to quickly treat this by dissolving the thrombus with a low risk of brain hemorrhage. In this study, we concentrate on the design of a high-performance microstirrer to dissolve the thrombus. The piezoactuator is selected and discussed because it has both sensing and actuation functions, and has a high power in relation with its size. Further, a new type of microstirrer is designed to generate high-amplitude vibration, and its motion can be easily controlled by adjusting the input signals to the actuators. Several types of microstirrers were manufactured on the basis of the finite-element method (FEM) simulation results, and the effect on the dissolution was experimentally validated.

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Supplements:

The thrombus characteristic is changed during the formation environment or the dissolving by medical treatment. We have to control the physical vibration for attack the thrombus depending on characteristics. We presented a treatment method of utilizing micro stirrer attached on the catheter tip about following figure. The micro stirrer contains the piezo-actuator and hinge structure in which the longitudinal vibration of the actuator will be converted to a bending vibration at the tip.

fig1

We have been successful in driving the micro stirrer to draw a trajectory by controlling the input voltage to the piezo-actuator. And the performance of several vibration modes owing to the effect of stirring was validated experimentally using the imitated thrombus (using the glycerol) as follow.

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In the future, we plan to study about the way to remove the thrombus more quickly and safety by controlling the trajectory of vibration depending on the characteristic of thrombus.

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