JP2003339715A - Releasable embolus coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a releasable embolus coil capable of strongly holding a connection part even when extension stress acts on the coil and capable of expecting that a filament can be brought back and recovered out of a living body even if a wire is drawn in the living body and the coil is extended in the living body to become a state getting loose. <P>SOLUTION: In the releasable embolus coil composed of a coil comprising a filament and a wire having a cutting-off part at its leading end, a part where the filament crosses at least at two or more places is present in the connection part of the coil and the cutting-off part. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detachable embolic coil for placing a required indwelling member at a required location in a living body through a tubular organ.

[0002]

2. Description of the Related Art Generally, there are various problems in treating a living body accompanied by a surgical operation. For example, the patient to be operated must endure long-time operation, and the operator is forced to concentrate nerves for a long time, and the risk of infection is relatively high. In order to reduce such various burdens and perform necessary surgery more safely and conveniently, recently, embolization materials for occluding tubular organs such as catheters, guide wires, blood vessels, etc. Medical devices have been developed and put into practical use.

[0003] For example, recent advances in medical devices such as catheters and guide wires have led to the practice of endovascular surgery for approaching a desired affected site from within a blood vessel, particularly arteriovenous malformations and cerebral aneurysms. , Has been widely applied to the treatment of diseases such as carotid-cavernous sinus thinning. At present, detachable balloons, coils, liquid embolic substances, particulate embolic substances, etc. are used as tubular organ embolic materials.

However, these embolic materials that are usually placed in a tubular organ or the like, once they are placed or released in the wrong position, it is almost impossible to recover them or correct their positions. Is.

Under the circumstances described above, it is possible to pull back and reinsert it even if it fails to place it at a desired place in the past, and after confirming the placement place, the embolic material is detached and placed. Detachable embolic materials that can be used have been proposed.

[0006] For example, as a method of connecting the disconnecting portion and the coil, Japanese Patent No. 2501389 discloses a method of soldering, and Japanese Patent No. 2641715 discloses an improvement in that a stainless steel rope portion is provided at the tip of the guide wire. A method of disposing the thrombus-forming member through a guide wire by placing the thrombus-forming member through the stainless steel portion after arranging the thrombus-forming member at a required position and placing the thrombus-forming member in the aneurysm Is proposed.
Further, in this method, a means is adopted in which an electric current is passed through the guide wire to electrolyze the stainless steel portion at the distal end portion of the guide wire to separate the thrombus forming member.

Further, as an example of a method for connecting the stainless portion and the coil, Japanese Patent Application Laid-Open No. 7-265431 discloses bonding with an adhesive, welding, connection by physical force, and Japanese Patent Application Laid-Open No. 8-25.
2323 discloses a method of solderlessly connecting a core wire (separation part) having a separable sacrificial link capable of electrolytic decomposition in blood and an elongated tip part (coil).

[0008]

According to the soldering method disclosed in Japanese Patent No. 2501389, as a method of connecting the detaching portion and the coil, the detaching portion must withstand the temperature at which the solder melts, and is made of metal. It had to be. Further, since many metals that are toxic to the living body are used for the solder, it is not preferable to use them as a part of the material left in the living body.

As an improved connection method thereof, Japanese Patent No. 2641715 discloses a method of crimping or welding a coil to a core wire by using a metal sleeve, and connecting the disconnection portion and the coil without using solder. However, according to these methods, there is a drawback that when the coil is stretched and unwound and pulled in a filament state, it breaks from the cut portion with extremely weak strength as compared with the strength of the filament.

When the coil is pressure-bonded to the sleeve and the core wire, it is difficult to obtain the same strength as that of the filament itself, because the helically wound filament is stretched in the unraveling direction. Moreover, the filament itself is easily damaged by the pressure bonding, and the damaged part may become a weak point and break.

Further, when the coil is welded to the sleeve or the core wire, the filament itself of the coil is once melted by heat or is affected by the heat, so that the crystal structure of the filament is changed, and The connection strength of the detached part was extremely low compared to the strength of the filament itself.

[0012] On the other hand, Japanese Patent No. 2880070 discloses a connection by an adhesive such as cyanoacrylate as a connecting means between a disconnecting part (connecting member) and a coil (in-vivo indwelling member) by adhesion. However, according to this method, since the breaking strength of the adhesive itself is largely due to the connection strength, it is possible to obtain a strength much smaller than the strength of the coil filament.

[0013]

DISCLOSURE OF THE INVENTION As a result of intensive studies made by the present inventors in view of the above problems, in a detachable embolic coil formed by using a coil made of a filament and a wire, the coil and the wire are connected to each other. We have developed a detachable embolic coil in which the filaments have intersecting portions at at least two positions.

Further, in a detachable embolic coil composed of a coil made of a filament and a wire having a detached portion at its tip, a portion where the filament intersects at least at two or more places in a connecting portion between the coil and the detached portion. Has developed a detachable embolic coil.

According to this detachable embolic coil, even when a tensile stress is applied to the detachable embolic coil during an operation or the like, a tightening stress is generated at a crossing portion at two or more places in the process of uncoiling the coil into a filament shape. Then, it becomes possible to firmly hold the connection portion.

Furthermore, the detachable embolic coil described above has been developed in which the filament on the rear end side of the portion where the filaments intersect at two or more places is closely adhered, adhered, welded or crimped to the detached portion. According to this, higher connection strength can be obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The detachable embolic coil according to the present invention is formed by using a coil made of a filament and a wire, and the filament is provided at least at two or more places in the connecting portion between the coil and the wire. It is a structure with intersecting parts. More preferably, the wire has a disconnecting portion at the tip thereof, and in the connecting portion between the coil and the disconnecting portion, there is a portion where the filament intersects at at least two positions.

Here, "the portion where the filaments intersect at at least two or more places" means that not only the spiral advances in one direction like a normal spiral coil, but also the angle of the spiral changes, for example. Because of this, the spiral goes in the opposite direction at a certain position, intersects with the original spiral, and when returning to the original direction, it intersects with the original spiral again. (However, in order to facilitate understanding, the filament shape is assumed to be spiral here, but various filament shapes are possible). A pattern example corresponding to "a portion where filaments intersect at at least two or more places" will be specifically described below (however, the present application is not limited thereto). The advancing direction of the spiral is reversed at a certain position with respect to the advancing direction of the original spiral, and at that time, after passing through the inside of the original spiral and the first intersection, the advancing direction of the spiral is reversed again ( The pattern is the traveling direction of the spiral with and), and at that time, a pattern occurs where the second intersection passes through the outside of the original spiral (first pattern example). The traveling direction reverses at a certain position with respect to the traveling direction of the original spiral, and at that time, after passing through the outside of the original spiral and the first intersection,
A pattern in which the advancing direction of the helix is reversed again (becomes the advancing direction of the original helix), and at that time, a second intersection passes through the inside of the original helix (second pattern example). In the first or second pattern example, a pattern in which the filament makes one rotation or more between the first crossing and the second crossing (third pattern example).
Furthermore, in the first, second, or third pattern example,
A pattern in which the number of intersections is greater than two, or each pattern may be repeated a plurality of times or may be combined. As described above, there are various methods for forming "intersections of filaments intersecting at least at two or more places".
From the viewpoint that the connecting portion can be formed to have a smaller diameter, the number of intersecting portions is preferably two, and the third pattern example is preferable among the above pattern examples.

On the other hand, the advancing direction of the spiral is reversed at a certain position with respect to the advancing direction of the original spiral, and at that time, after passing through the inside of the original spiral and the first crossing occurs, the advancing direction of the spiral again. If the spiral forming the coil ends without being reversed, it is possible to achieve the object of the present invention even if it has only "a portion where the filament intersects".
At this time, it is possible to cross at two or more places. In the following, there may be a case where the filament is crossed at least at two or more places, but only the above "the portion where the filaments intersect at one place" is not impaired for the purpose of the present application. It shall be possible to adapt when it has.

Here, as the coil shape, various shapes such as a spherical spiral shape, an S shape, a spiral shape with a changing radius, and a shape provided with a temporary shape and a secondary shape are possible. A secondary coil shape in which the shape is a spherical spiral shape and a spherical secondary spiral shape is further provided is preferable.

In the detachable embolic coil according to the present invention, when the coil made of the filament is connected to the wire, the wire or the filament arranged outside the disconnecting portion intersects at least at two or more places. Characterize.

In particular, it is preferable that the proximal side of the "portion where the filaments intersect at at least two or more places" of the coil is wound in close contact with the separation portion and is fixed to the separation portion.

Furthermore, it is preferable that the proximal side of the "portion where the filaments intersect at at least two or more places" of the coil is fixed to the cut-off portion by adhesion or welding.

The "intersection where the filaments intersect at at least two points" tends to be larger than the outer diameter of the coil in which the filaments are spirally wound. It is more preferable that the outer diameter is almost the same as
If the separating portion is made of a hard metal, the filament is likely to be damaged. Therefore, the separating portion is preferably made of a metal softer than the resin or the filament.

In particular, when the detaching portion is polyvinyl alcohol, the detaching portion is heated by supplying the monopolar high frequency current through the wire body, and the coil can be detached, which is more preferable.

However, the separating portion is not limited to polyvinyl alcohol, and is, for example, Japanese Patent No. 2501.
It is also useful when the coil is joined to the detached portion of the stainless steel or the detached portion via a sleeve as disclosed in Japanese Patent No. 389 or No. 2641715.

On the other hand, it is also possible to preliminarily thinly process the wire at the "intersection where the filaments intersect at at least two or more places" or the cut-off portion. According to this, it is possible to prevent the coil from becoming larger than the outer diameter.

Further, Japanese Patent Nos. 2584956 and 260
It can also be applied to the joining of one side of a detaching part of a mechanically fitting type such as a hook shape and a ball shape disclosed in No. 2625 and a coil.

(Operation) A detachable embolic coil according to the present invention is a detachable embolic coil formed by using a filament coil and a wire, wherein the filament is present in the connecting portion between the coil and the wire. At least 2
Due to the structure where there are intersections at more than one place, even when tensile stress is applied to the detachable embolic coil during surgery, the coil unravels and tightens at the intersections at two or more places in the process of becoming a filament. Stress is generated, and it becomes possible to firmly hold the connection portion.

The detachable embolic coil of the present application will be described below with reference to the drawings, but the present application is not limited thereto.

An overall view of an example of the detachable embolic coil of the present invention is shown in FIG. The detachable embolic coil of this example has a wire body 10 in which the tip of a tapered stainless alloy wire is covered with stainless steel and a platinum alloy coil and welded as a basic constituent member (the outer diameter of the minimum diameter portion is 0.2 mm or more. The outer diameter of the maximum diameter portion is preferably 1.0 mm or less.), And a rod-like disconnection provided by connecting the rear end to the front end of the wire body 10 and being cut by heating. Part 11 (outer diameter is 0.05 mm or more,
It is preferably 0.50 mm or less. Total length is 1 mm
As described above, it is preferably 100 mm or less. )When,
A spirally wound coil 12 (a filament outer diameter of 0.02 mm or more
0.12 mm or less, more preferably 0.035 mm or more and 0.10 mm or less, and the primary coil diameter is 0.1 m.
It is preferably m or more and 1.2 mm or less. ).

As the material of the filament forming the coil, platinum (platinum), tungsten, gold, tantalum,
Iridium and alloys arbitrarily selected from them can be used, but platinum alloys, and alloys of platinum and tungsten are particularly preferable. Further, the cross-sectional shape of the filament is not limited to a circle,
Various shapes such as an ellipse, a quadrangle, and a triangle can also be applied. Further, it is preferable that the primary coil further has a secondary coil shape or a three-dimensional shape, and the distal end side is rounded so as not to damage the living body.

Polyvinyl alcohol copolymer is preferably used as the material of the cut-off portion, and the cut-off portion can be melted by heating by using high frequency power.

However, the separating portion is not limited to polyvinyl alcohol, and for example, Japanese Patent No. 2501
It is also useful when the coil is joined to the detached portion of the stainless steel or the detached portion via a sleeve as disclosed in Japanese Patent No. 389 or No. 2641715.

Further, Japanese Patent Nos. 2584956 and 260
It can also be applied to the joining of one side of a detaching part of a mechanically fitting type such as a hook shape and a ball shape disclosed in No. 2625 and a coil.

[0036]

(Example 1) A coil was formed at a position corresponding to a connecting portion of a coil and a disconnecting portion, in particular, a structure corresponding to the first pattern example shown above so that filaments intersect at two positions. The photographs are shown in FIGS.

(Embodiment 2) At a position corresponding to a connecting portion between a coil and a disconnecting portion, a structure corresponding to the third pattern example described above (especially, filaments intersect at two places, and the coil makes one turn during the intersection). The coil was formed into a structure having The photographs are shown in FIGS.

According to this method, the shape of the spiral on the back side of the intersection becomes constant as shown in FIG. Furthermore, when a connecting member is inserted and the portion swelled due to the intersection is closely adhered to the outer diameter of the coil, damage to the filament is small and the appearance is natural, which is preferable.

(Embodiment 3) The diameter of the primary coil made of platinum alloy wire having a diameter of 0.06 mm is 0.36 mm,
The in-vivo indwelling member (coil) having a secondary coil shape with a secondary coil diameter of 5 mm was crossed as in Example 2 (FIGS. 4 and 5) at a position approximately 0.3 mm from the end. Further, a cylindrical rod-shaped connecting member (disconnecting portion) having a diameter of 0.15 mm and a length of 10 mm, which is made of a polyvinyl alcohol-based copolymer, is inserted from the base end portion by about 1.3 mm, and is closely adhered to and fixed to the connecting portion. Was further bonded with an adhesive made of cyanoacrylate (FIG. 6) to prepare 5 points.
Fix both ends of the connecting member and the coil, and use a tensile tester to
As a result of measuring the tensile strength at a speed of 00 mm / sec, an average value of 3.2 N (standard deviation 0.2 N) was obtained. Further, FIG. 7 shows the holding state during the measurement of the tensile strength.

(Comparative Example 1) The same as Example 3 except that the portion where the filament intersects was not formed at the position corresponding to the connecting portion of the coil and the disconnecting portion, and the coil base end portion was crimped and fixed to the connecting member. . In the same manner as in Example 3, five points were prepared by fixing the fixed parts with an adhesive made of cyanoacrylate. As a result of the tensile test, the average value was 1.4 N (standard deviation 0.2 N).

(Comparative Example 2) The procedure of Example 3 was repeated, except that a portion where the filament intersects was not formed at the position corresponding to the connecting portion between the coil and the disconnecting portion, and the coil end portion was welded into a ring shape. In the same manner as in Example 3, the fixing part was bonded with an adhesive made of cyanoacrylate to 5
I made points. As a result of the tensile test, the average value is 1.7 N
The tensile strength was (standard deviation 0.2 N).

Although the embodiments have been described above, various modifications can be made in the present invention. For example, not only the connection of the indwelling member in the living body, the connection of the wire main body and the disconnecting portion, and not limited to a single wire, further a plurality of coils of appropriate length and the connecting portion is connected in sequence. Can also be connected.

In the present invention, various connections can be used for connecting the in-vivo indwelling member.
It can be applied to a linear member having a medical action or a medical auxiliary action by the coil body or other detention.

[0044]

As described above, the detachable embolic coil of the present invention is tightened at a crossing portion at two or more points in the process of uncoiling and forming a filament even when a tensile stress is applied to the coil. A stress is generated, and it is possible to firmly hold the connection part. Thereby, even when the wire is pulled in the living body and the coil is stretched and released in the living body, it can be expected that the filament can be pulled back to the outside of the body and collected. As a secondary effect, it is expected that the manufacturing is easy because the structure is very simple.

[Brief description of drawings]

FIG. 1 is an overall view of an example of a detachable embolic coil according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a specific means of a coil 12 that intersects at least two points.

FIG. 3 is a shape diagram of the back side when FIG. 2 is the front side.

[Fig. 4] Coil 1 in which the intersection is shifted about one turn in the spiral direction.
It is explanatory drawing which shows an example of 2 concrete means.

5 is a shape diagram of the back side when FIG. 4 is the front side. FIG.
There is no intersection, and the coil arrangement is the same as the standard coil arrangement.

FIG. 6 shows a coil having a cross formed in Example 2 in which a connecting portion is inserted and closely attached.

7 is a schematic shape held at an intersection when a tensile stress is applied to the sample prepared in FIG.

[Explanation of symbols]

10 wire body 11 Separation part 12 coils 15 intersection

Claims (15)

[Claims] 1. A detachable embolic coil formed by using a coil made of a filament and a wire, wherein a portion where the filament intersects at at least two positions is present in a connecting portion between the coil and the wire. Detachable embolic coil. 2. A detachable embolic coil comprising a coil made of a filament and a wire having a detached portion at its tip, and a portion where the filament intersects at least at two or more places in a connecting portion between the coil and the detached portion. There is a detachable embolic coil. 3. The detachable embolic coil according to claim 1, wherein a part of the wire is inserted inside a portion where the coil filaments intersect at two or more places. 4. The detachable embolic coil according to claim 2, wherein a part of the separating portion is inserted inside a portion where the filaments intersect at two or more places. 5. The detachable embolic coil according to claim 1, wherein at least the filament on the rear end side of the portion where the filaments intersect at two or more locations is in close contact with the disconnecting portion. 6. The detachable embolic coil according to claim 1, wherein at least the filament on the rear end side of the portion where the filaments intersect at two or more locations is adhered to the separating portion. 7. The detachable embolic coil according to claim 1, wherein at least the filament on the rear end side of the portion where the filaments intersect at two or more locations is welded to the disconnecting portion. 8. The detachable embolic coil according to claim 1, wherein at least the filament on the rear end side of the portion where the filaments intersect at two or more places is crimped to the separating portion. 9. The detachable embolic coil according to claim 1, wherein at least portions of the filament that intersect at two or more locations are crimped to the separating portion. 10. The detachable embolic coil according to claim 1, wherein the coil has a secondary coil shape. 11. The detachable embolic coil according to claim 1, wherein the coil has a three-dimensional shape. 12. The filament material is an alloy of platinum, tungsten, gold, tantalum, iridium, and any combination thereof.
11. The detachable embolic coil according to each of items 1 to 11. 13. The detachable embolic coil according to claim 1, wherein the material of the detachable portion is capable of dissolving in body fluid. 14. The detachable embolic coil according to claim 1, wherein the material of the detaching portion is polyvinyl alcohol. 15. A detachable embolic coil formed by using a coil made of a filament and a wire, which is advanced at a certain position in the connecting direction between the coil and the wire with respect to the original traveling direction of the filament. A detachable embolic coil in which the direction is reversed and at least one intersection occurs by passing inside the original filament at that time.