JPS6314860Y2 - - Google Patents

Description

[Detailed description of the invention]: Background technical field of the invention The present invention relates to a medical guide wire used in angiography and the like.

Prior art and its problems Traditionally, medical guidewires have been required to have flexibility as a whole in order to be introduced along the inner wall of blood vessels to the target site, and in particular, sufficient flexibility at the tip has been required. has been requested. In order to provide this flexibility, as shown in FIG. 1, both ends of the core body 5, which consists of a tip part 1 with low bending elasticity and a base part 2 with high bending elasticity, and the periphery of the core body 5 are covered. There is a medical guide wire in which both ends of a tight spiral body 3 are fixed by fixing parts 4, 4.

When the medical guide wire is inserted into the target site from the distal end 1 along the three-dimensionally winding blood vessel wall, both ends of the core body 5 and both ends of the tight spiral body 3 touch the fixing parts 4, 4. Due to the fixed structure, the distance between the helical bodies at the bent part becomes wider on the outside of the bend, but on the inside of the bend, the core body 5 hardly stretches, so there is no winding. There is a force that tries to narrow the gap between them. Since the spiral body 3 is in close contact along its entire length,
The force that tries to contract becomes very large, and this force becomes a tension force on the core body 5 in the direction of both ends. The drawback was that it could damage blood vessel walls.

:Purpose of the invention The purpose of the invention is to provide a medical guidewire that solves these problems and drawbacks and does not damage the inner wall of the blood vessel when it is bent three-dimensionally within the blood vessel when inserted into the blood vessel. do.

The above-mentioned object is achieved by a medical guidewire comprising a core body having a tip portion with low bending elasticity and a base portion with high bending elasticity, and a densely wound helix that encases the core body and has both ends fixed to both ends of the core body, in which a portion of the helix is provided with a sparsely wound portion.

Further, in the present invention, it is preferable that the helical body has sparse windings in a region where the initial tension is small.

Further, in the present invention, sparse windings may be provided on the base side of the core, sparse windings may be provided on the fixed end side of the spiral body at the base of the core, and the sparse windings may be provided on the helical fixed end side of the base of the core. The diameter may be smaller than the diameter of the base, and further,
The core body and the spiral body may be made of corrosion-resistant members.

:Specific explanation of the invention-1 Configuration The helical body 3 of the medical guide wire of the invention is as follows:
When winding the wires around the mandrel, while applying force in the direction so that they overlap, the wire is simply applied in the direction where the initial tension is small, so that the wires are By winding it at a 90° angle, regions with high initial tension and regions with low initial tension are formed.

Here, the parts with a large initial tension are the parts that are wound while applying force in the overlapping direction, and the parts with a small initial tension are the parts that are wound so that they are adjacent to each other.

In the medical guide wire of the present invention, a core body 5 having a distal end portion 1 with low bending elasticity and a base portion 2 with high bending elasticity is inserted into the helical body 3, as shown in FIG. 5 and both ends of the spiral body 3 are fixed.

The region where the initial tension is small is formed by sparse windings 7, as shown in FIG. The sparse windings 7 may be provided anywhere on the spiral body 3, preferably on the base side of the core body 5, and more preferably on the side of the spiral body fixed end of the core body base.

Further, the diameter of the tip 1 of the core body 5 is made smaller than the diameter of the base 2 to reduce bending elasticity.

Since the core body 5 has almost no elasticity in the longitudinal direction, the total length _l2 of the core body 5 is constant regardless of the bending of the core body 5, but the total length of the spiral body on the small side of the radius of curvature
Considering the free movement of the core body 5, l ₁ is shorter than the total length l ₂ of the core body 5, so that the helical body 3 is redundant by l ₂ −l ₁ . If the spiral body has many dense turns, it will not be contracted in the longitudinal direction, so a repulsive force against compression will act on the extra portion, and a tensile force will act on the core body 5 in the longitudinal direction, making it difficult for the core body 5 to bend. Therefore, free bending of the core body 5 is inhibited.

In the medical guide wire according to the present invention, which has sparse turns 7 with a small initial tension in a part of the helical body 3, the l ₂ −l ₁ portion is absorbed by the sparse turns 7, so that the core body 5 Since the tension does not work, the free bending movement of the core body 5 is not inhibited.

Also, the total length of the helix on the side with the larger radius of curvature l ₃
can be easily stretched because the initial tension of the sparse windings 7 is small, and the total length l ₃ of the spiral body 3 on the side with a large radius of curvature becomes large, and the relationship l ₃ > l ₂ can be established easily. can. That is, by providing the sparse windings 7, it becomes possible to easily create the relationship l ₃ > l ₂ > l ₁ without generating unreasonable force, and no tensile force is applied to the core body 5. Therefore, even when the medical guide wire according to the present invention is bent, the tension in the direction of both ends of the core body 5 is reduced, and the flexibility of the tip can be maintained.

Here, making the helix sparse over the entire length or reducing the initial tension will reduce the initial tension of the entire helix, which will worsen the restorability of the medical guidewire as a whole, especially the flexible tip. Not desirable.

-2 Effects The configuration of the medical guide wire according to the present invention when inserted into a three-dimensional blood vessel along the blood wall is shown in FIGS. 4 and 5.

Since the medical guide wire is inserted into a three-dimensional blood vessel along the blood vessel wall, a certain degree of bending occurs. , 4, the extra length of the spiral body 3 caused by bending moves to the sparse part,
The tensile force on the core body 5 is relaxed, flexibility is maintained at the distal end, and the guide wire can be easily inserted along the blood vessel wall. In this case, the spiral body 3 remains dense on the side with a smaller radius of curvature, and becomes sparse on the side with a larger radius of curvature. Spiral 3
The total length of the side with the larger radius of curvature l ₃ and the total length of the core body 5 are
l ₂ , the total length l ₁ of the spiral body 3 on the side with the smaller radius of curvature is
Since the force in the direction that prevents l ₃ > l ₂ > l ₁ along the blood vessel wall is absorbed by the loose windings, the generation of this force can be reduced. In other words, when bending, l ₃ >
The force that is about to become l ₂ is applied to the part 5a where the initial tension is small.
The outer windings of the helix easily widen to absorb it.

-3 Effects The present invention consists of a core body having a tip portion with low bending elasticity and a base portion with high bending elasticity, and a dense material that encloses the core body and has both ends fixed to both ends of the core body. In a medical guide wire consisting of a wound helix, a portion with a small initial tension is provided in a part of the helix, and preferably the portion with a small initial tension is made into a sparse wound, so that three-dimensional intravascular Even when inserted into a blood vessel and bent, the core body is not subjected to unreasonable force and can be moved to take advantage of its properties, and the tip maintains sufficient flexibility, thereby eliminating the risk of damaging the inner wall of the blood vessel. This will further reduce the burden on patients.

Further, by providing the sparse windings on the base side of the core body, more preferably, by providing the sparse windings on the helical body fixed end side of the base of the core body, the sparse windings are formed during use. It becomes possible to exist outside the body, and there is no risk of pinching the blood vessel wall or increasing blood flow into the helical body due to the expansion and contraction of the sparse windings.

Furthermore, by making the diameter of the tip of the core smaller than the diameter of the base of the core, a tip with better flexibility can be obtained even when the core is made of one material. , which prevents damage to blood vessel walls during use. Furthermore, since the helical body is made of a corrosion-resistant material, it can withstand long-term indwelling in the blood vessel, and there is no fear that the corroded part will peel off into the blood vessel during use and cause adverse effects.

Next, the present invention will be explained in detail by way of examples.

A medical guide wire according to the present invention having a total length of 1500 mm and a diameter of 0.96 mm with a gap of 0.05 mm between each helix between 150 mm on the fixed end side of the helix at the base of the core body is attached at the tip end as shown in Figure 6. 45mm from the tip with the fixing jig 8, and load point 9 25mm from the tip.
A load was applied to move the tip portion by 2 mm in the vertical direction.

At this time, the base side is a storage case 1 with a diameter D = 140 mm.
0, and the bending load value changes depending on the number of windings of the base part stored in the storage case 10,
It was measured by the load sensor 11.

Similarly, conventional products on the market (full length
A medical guide wire (1500 mm, diameter 0.89 mm) was also measured using the same measurement method, and the results were compared with the measurement results of the medical guide wire according to the present invention, and a graph is shown in FIG. Point b on the graph is a medical guide wire according to the present invention, particularly a medical guide wire in which a part of the helical body is provided with loose windings, and point c is a conventional product.

As can be seen from these results, the medical guidewire according to the present invention maintains sufficient flexibility at its distal end even when bent during use.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional medical guide wire, Fig. 2 is a sectional view of a medical guide wire showing an embodiment of the present invention, and Fig. 3 is a sectional view of a medical guide wire showing another embodiment of the present invention. Cross-sectional view of the guide wire, No. 4
The figure is a cross-sectional view of the medical guide wire of the present invention when bent, Figure 5 is a cross-sectional view of the medical guide wire of the present invention when bent, and Figure 6 is a cross-sectional view of the medical guide wire of the conventional product and the present invention. Elevation view of the device for comparison of tip flexibility when
The figure is a diagram showing the results of measurement using the apparatus of FIG. 6.

Claims (1)

[Claims for Utility Model Registration] (1) A core body having a tip portion with low bending elasticity and a base portion with high bending elasticity, and a core body that encloses the core body and has both ends fixed to both ends of the core body. What is claimed is: 1. A medical guide wire comprising a tightly wound helical body, characterized in that a part of the helical body is provided with a sparsely wound portion. (2) The medical guide wire according to claim 1, wherein the sparse windings are on the base side of the core body. (3) Utility model registration claim 1, in which the sparse windings are on the side of the helical body fixed end portion of the core body base.
The medical guide wire according to item 1 or 2. (4) The medical guide wire according to any one of claims 1 to 3, wherein the diameter of the distal end of the core is smaller than the diameter of the base. (5) The medical guide wire according to any one of claims 1 to 3, wherein the core body and the spiral body are made of a corrosion-resistant member.