JP2016189884A - Polymer actuator drive catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a catheter to be inserted into a narrow or thin region.SOLUTION: A polymer actuator drive catheter has electrode patterns composed of a plurality of electrodes. An electrode pattern on the catheter's root side differs from that on the catheter's tip side. Thereby, the catheter's tip side and root side are capable of being bent/deformed in different directions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polymer actuator drive catheter.

  Catheter treatment is one of the major techniques of current vascular surgery. Many catheter procedures begin by passing a guide wire through the target vessel. In order to pass the guide wire, the catheter and the guide wire of FIG. 2 are used, and as shown in 1) to 4) of FIG. However, when arteriosclerosis progresses and the inner diameter of the blood vessel becomes thinner, it becomes difficult to pass the catheter through the blood vessel opening. To solve this problem, there is a possibility that precise and rapid surgery can be performed by robotizing the technique. A polymer actuator drive catheter is one of them.

  In 1999, Azumi et al. Proposed a polymer catheter for intravascular surgery (Non-patent Document 1). It has a catheter shape with a diameter of 1 mm, and has a structure in which electrodes divided into four by laser cutting are arranged on the surface. In 2014, a group such as Kwang J Kim et al. From the University of Nevada succeeded in reducing the cost of manufacturing a polymer catheter by Azumi et al. Instead of laser processing the tube, they made a prototype of a tube that had a protrusion shape on the part to be split in advance, and realized the split by cutting the protrusion after gold plating.

  However, since the actuator described in Non-Patent Document 2 performs uniform electrode patterning in the axial direction, a large bending performance cannot be obtained from the relationship between the driving force of the polymer actuator and the second moment of section of the catheter. The team at Nevada University prototyped a cylinder actuator with a length of 20 mm and a diameter of 1 mm. The bending displacement obtained by applying a voltage of 2 V was about 2 mm and the bending angle was about 15 degrees. There is no need to secure all of the bending performance of the catheter with a polymer actuator, but this restriction becomes a major obstacle when it becomes necessary to bend in a limited space such as deep in the brain.

  First, the polymer actuator drive catheter has two major roles. One is an operation of selecting a blood vessel passage in a Y-shaped branch blood vessel. In the conventional catheter procedure, a bending displacement is realized by using a catheter having a bent tip in advance and passing a guide wire therethrough. Similarly, a catheter with a bent tip is also used for a polymer actuator driving catheter, and the polymer actuator is required to be assisted and adjusted. For this purpose, a relatively large bending deformation amount of 5 to 45 degrees is required as a necessary bending angle.

  The other is the operation of correcting the distal end position in order to insert the catheter into the branch vessel opening that is three-dimensionally in a twisted positional relationship. In the conventional catheter procedure, correction is performed by rotating the catheter from the outside. However, since the catheter itself is as long as 1 m and is a soft resin material, rotational displacement due to external operation is absorbed by the catheter and fine adjustment is performed. There was a problem that was difficult. Since the polymer actuator drive can transmit the displacement directly through the catheter tip by an electric signal, it is very well adapted to the same procedure. For this purpose, a relatively small bending deformation amount of 3 to 15 degrees is required.

  In contrast to the bending performance with different required specifications, it is difficult to satisfy two different performances with an actuator having the same bending range in a catheter having uniform electrode patterning in the axial direction.

K. Oguro, N. Fujiwara, K. Asaka, K. Onishi, S. Sewa, “Polymer Electrolyte Actuator with Gold Electrodes”, Proc. SPIE 3669, Smart Structures and Materials (1999) Seong J. Kim, David Pugal, Johnson Wong, Kwang J. Kim, Woosoon Yimb, “A bio-inspired multi degree of freedom actuator based on a novel cylindrical ionic polymer-metal composite material”, Robotics and Autonomous Systems 62, pp. 53-60 (2014)

  An object of the present invention is to provide a technique that allows a catheter to be inserted into a complicated shape or a thin blood vessel site.

The present invention provides the following polymer actuator drive catheter.
Item 1. A polymer actuator drive catheter having an electrode pattern composed of a plurality of electrodes, wherein the electrode pattern is different on the root side and the distal end side of the catheter, so that the distal end side and the root side of the catheter can be bent and deformed in different directions A polymer actuator-driven catheter.

  The polymer actuator drive catheter of the present invention can be operated intuitively and easily.

  Since the polymer actuator drive catheter of the present invention can finely adjust the directions of the root side and the tip side independently, catheter treatment can be performed even for stroke, occlusive peripheral arterial disease and kidney disease, which are difficult to operate with conventional catheters. Can do.

  If the present invention is applied, the electrodes can be arranged in accordance with the portion that is desired to be indirect, so that an S shape, an M shape, and a three-dimensional twist can be realized by bending.

Polymer actuator drive catheter having an electrode pattern with four electrodes at the tip Intravascular catheter and guidewire The embodiment when inserting a wire into a branch vessel using a catheter and a guide wire. 1) A guide wire is visible in front of the blood vessel bifurcation, 2) The catheter is extended in front of the guide wire, the catheter approaches the blood vessel bifurcation, 3) The tip of the catheter reaches the branched blood vessel, 4 ) A guide wire is fed forward along the catheter to introduce the guide wire into the branched blood vessel. Driving principle of polymer actuator An example of an electrode placement optimization catheter Voltage and bending direction of polymer actuator drive catheter Extrusion mold, 1) Overall view, 2), 3) Moving the movable mold. The melted Nafion is pushed out into the gap (white part) made of the mold. An example of processing by extrusion, 1) Extrude the tip. 2) and 3) are transition states from the tip to the main body. The movable mold is moved while extruding. 4) Extrude the main unit Wrap membranous Nafion to make a hollow tube Electrode splitting is realized by gold plating on the tube and removing the protrusions. (A) Hollow tube produced in FIG. 9, (B) Hollow tube after gold plating, (C) Electrode split after removal of convex portion

  The polymer actuator drive catheter is composed of a polymer actuator body and electrodes. The material of the polymer of the actuator body is not particularly limited, but a material containing a conductive polymer gel is preferably exemplified, and more preferably, a fluororesin cation exchange having a sulfonic acid group, a carboxylic acid group or the like as a dissociating group Examples thereof include an ion conductive polymer gel containing a resin, an anion exchange resin having an ammonium group, and the like.

  The polymer actuator body has a cylindrical shape, and the inner diameter of the actuator body needs to be larger than the outer diameter of the guide wire so that the guide wire can be passed through the polymer actuator body.

  The catheter is inserted from outside the living body into the living body, and proceeds through the blood vessel in the living body. The catheter may be inserted into the blood vessel alone, but is preferably inserted into the blood vessel with a guide wire passed through the catheter.

  The tip of the catheter or guide wire includes a straight type and a bent type of about 5 to 90 °, and an angled type is preferable for guiding into a largely bent blood vessel. By appropriately guiding the catheter tip to the vicinity of the surgical site by catheter guidance and replacing the internal guide wire with the corresponding surgical instrument, aortic aneurysm, ischemic heart disease, cerebral aneurysm, obstructive peripheral arterial disease, liver, etc. It can be applied to cancer treatment of tissues having many blood vessels inside.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the actuator drive catheter of the present invention is provided with an electrode pattern of a plurality of electrodes on the outer surface of a cylindrical polymer. The electrode can be formed by plating a noble metal such as gold, platinum, or palladium, and an electrode pattern composed of a plurality of electrodes can be formed by uniformly splitting the electrode after the noble metal plating is uniformly performed. . The catheter of the present invention has different electrode patterns on the base side and the tip side. Although the number of the electrodes in one electrode pattern is not specifically limited, For example, 2-16, especially 2-8 are mentioned. FIG. 1 shows an electrode pattern composed of four electrodes, and FIG. 6 shows that the four electrode patterns can be bent and deformed in eight directions.

  Since the electrode pattern is different between the root side and the distal end side of the catheter, it has at least two electrode patterns. However, by forming at least one electrode pattern between the distal end side and the root side, a large bend of 90 ° or more is obtained. It is also possible.

  The driving principle of the polymer actuator driving catheter is shown in FIG. The polymer actuator drive catheter is composed of an electrode and a polymer gel. The polymer actuator drive catheter is bent by applying a voltage to the electrode, but the bending performance depends on the voltage and the electrode area. The larger the voltage or the larger the electrode area, the more the polymer actuator drive catheter can be bent.

  FIG. 5 shows an example of the polymer actuator drive catheter of the present invention. When the wiring / electrode arrangement as shown in FIG. 5 is performed, the distal end side of the polymer actuator driving catheter is bent in the front-rear direction, and the root side is bent in the left-right direction. In FIG. 5, the tip side has an electrode pattern including a second electrode on the near side and a fourth electrode on the back side, and an electrode pattern composed of four electrodes from the first electrode to the fourth electrode is formed on the base side. Yes. Since the area of the second electrode and the fourth electrode on the base side (lower side) is very small, the bending direction on the base side is practically determined by the first electrode (left side) and the third electrode (right side) having a large area.

  When a voltage is applied to the first and third electrodes on the base side having a large electrode area, and the second and fourth electrodes on the tip side, the root side and the tip side are bent in different directions, so the catheter is bent in the desired direction. Can be deformed. When the voltage of the electrode is lowered, the bending is small, and when the voltage is high, the bending is large.

  FIG. 5 illustrates a catheter in which the direction of bending is orthogonal between the distal end side and the root side of the catheter, but an electrode pattern composed of four electrodes having substantially the same area is formed on the distal end side, and the root side is shown in FIG. When such an electrode pattern composed of two electrodes is formed, an actuator-driven catheter that can bend and deform in one direction on the base side and bend in eight directions on the tip side is obtained. Thus, the direction of bending can be finely adjusted by increasing the number of electrodes on the tip side.

  An example of the manufacturing method of the polymer actuator drive catheter of the present invention is shown in FIGS.

  FIG. 7 shows an example of a mold to be used. The mold shown in FIG. 7 is divided into three color-coded molds, and the base gray is a fixed mold, and red and yellow movable molds are installed. The movable mold moves as shown in 2) and 3) in FIG. 7, and the molten polymer passes through the white gap and is molded. The state of molding is shown in FIG. The distal end portion of the catheter is molded at the mold position shown in 1) of FIG. 8, and after the distal end portion is finished, extrusion molding is performed while the mold moves as shown in 2) and 3) of FIG. Finally, the main body is formed as shown in 4) of FIG. Then, the resulting film is circularly connected as shown in FIG. 9 to form a cylindrical shape. Then, the diameter is reduced by pulling both ends while applying heat. Thereafter, as shown in FIG. 10, after chemical treatment (sulfonation), gold plating is performed, and the convex portions are removed to realize electrode splitting. The chemical treatment process is the same as that of Azumi et al. Non-Patent Document 1, and the process of splitting the convex portion is the same as Non-Patent Document 2.

Claims (1)

A polymer actuator drive catheter having an electrode pattern composed of a plurality of electrodes, wherein the electrode pattern is different on the root side and the distal end side of the catheter, so that the distal end side and the root side of the catheter can be bent and deformed in different directions A polymer actuator-driven catheter.