JP4857755B2 - Medical detachable embolic wire with improved detachability - Google Patents

Description

  The present invention relates to a medical wire for placing a required indwelling member at a required location in a living body through a tubular organ.

  In general, there are various problems in the treatment of living bodies accompanied by surgical operations. For example, a patient to be treated must endure a long-time operation, and an operator is forced to concentrate nerves for a long time, and the risk of infection is relatively high. In order to alleviate such various burdens and to perform necessary operations more safely and simply, embolization materials for occluding tubular organs such as catheters, guide wires, blood vessels, etc. Various medical devices have been developed and put into practical use.

  For example, recent advances in medical devices such as catheters and guidewires have led to intravascular surgery approaching the desired affected area from within the blood vessel, especially arteriovenous malformations, cerebral aneurysms, carotid arteries It has been widely applied to the treatment of diseases such as cavernous sinus. At present, detachable balloons, coils, liquid embolic materials, particulate embolic materials, and the like are used as tubular organ embolic materials. However, these embolic materials that are usually placed in tubular organs, etc. are rarely collected or corrected once they are placed or released in an inappropriate position. Impossible.

  Under such circumstances, even if it has failed to arrange at the target location in the past, it can be pulled back and reinserted, and the embolic material can be removed and placed after confirming the location. Possible detachable embolic materials have been proposed.

  For example, in Patent Document 1, an in-vivo indwelling member is connected to a distal end portion of a conductive wire main body via a connection member, and the connection member is heated by supplying a cutting current via the wire main body. Thus, a medical wire from which the in-vivo indwelling member is detached has been proposed.

  In this conventional medical wire, a solid cylindrical rod made of a polyvinyl alcohol polymer is used as a connecting member. The connecting member is heated to a high temperature when a cutting current is supplied. As a result, the polyvinyl alcohol polymer forming the connecting member is dissolved in the swollen water contained in the polymer. It is cut by.

  Therefore, when using this medical wire, it is necessary that the connecting member is sufficiently swollen with water. When the swelling state is insufficient and the water content is insufficient, The amount of the connecting member forming material dissolved by the operation for supplying the cutting current is so small that the connection member cannot be cut unless the operation for supplying the cutting current is performed many times. Therefore, it is necessary to supply a high-frequency current with a large output as shown in Patent Document 2 as a cutting current, which may adversely affect the living tissue.

  Therefore, before inserting the medical wire into the living body, it is sufficient to swell the portion of the connecting member in the swelling water. However, in order to make the connecting member sufficiently swollen, a considerably long swelling treatment is performed. For example, in the case of a connecting member made of polyvinyl alcohol having an outer diameter of 0.2 mm, for example, there is a problem that it takes a long time of about 2 to 5 minutes for the swelling treatment.

Further, for example, in Patent Document 3, an in-vivo indwelling member is connected to a distal end portion of a conductive wire body by a sacrificial joint that can be dissolved electrolytically, and a cutting current is supplied via the wire body. Thus, there has been proposed a medical wire in which the in-vivo indwelling member is removed by convergent electrolysis found in the sacrificial site, but it has not yet been solved, for example, it takes a long time to disassemble. In addition, as in Patent Document 2, attempts have been made to improve the swelling speed by making the connection member an assembly of a plurality of fibrous elements, but no solution has yet been made, such as a reduction in strength.
JP-A-7-265431 JP2000-229086 Special table 2003-509211

  The present invention has been made on the basis of the circumstances as described above, and its purpose is to obtain a sufficient swelling state by a short swelling treatment and a sufficient strength so that there is little risk of cutting by operation. A medical device having an in-vivo indwelling member that can reliably disconnect the in-vivo indwelling member in a short time as a whole, and can disconnect the connecting member reliably by a cutting current supply operation. It is to provide a wire for use.

  As a result of intensive studies in view of the circumstances as described above, the present inventors have added a water-soluble salt to the water-swellable material that is the connecting member, so that the cutting reaction and swelling treatment can be performed without causing a decrease in strength. It has been found that the time can be significantly reduced, and the present invention has been achieved.

That is, the present invention
(1)
It consists of a wire body and an in-vivo indwelling member connected to the tip of the wire body via a connecting member made of a water-swellable material, and the connecting member is heated and cut by supplying a cutting current. In this case, in the medical wire having an in-vivo indwelling member, the water-swellable material is a polyvinyl alcohol polymer having an average degree of polymerization of 500 to 7000. And the connecting member contains 1 to 25% by weight of a water-soluble salt;
(2 )
The water-soluble salts are metal halides, carbonates, sulfates, nitrates, chlorates, hypochlorites, acetates, carboxylates, and phosphoric acids having a solubility in water of 10 wt% or more. further comprising at least one selected from the group consisting of salts, (1) Symbol placement of medical wire;
( 3 )
The water-soluble salt further comprises at least one selected from the group consisting of sodium chloride, potassium chloride, sodium sulfate, sodium nitrate, barium sulfate, sodium nitrate, sodium carbonate, and calcium phosphate, (1) or Medical wire according to (2) ;
I will provide a.

  According to the medical wire as described above, in the swelling treatment of the water-swellable material constituting the connecting member, a sufficient swelling state is achieved in a very short time, and therefore the time required for the swelling treatment is greatly reduced. When the cutting current is supplied and placed in the living body, since the connecting member contains sufficient water, the connecting member is easily and reliably cut, and thus high reliability is obtained. .

  Further, according to the method of the present invention, the characteristic performance of the above medical wire can be fully exhibited, and the indwelling of the in-vivo indwelling member can be performed in a very short time as a whole, including the swelling treatment. The treatment can be reliably achieved, thus greatly reducing the burden on the patient and the operator.

Hereinafter, the present invention will be described in detail with reference to the drawings.
<Embolic material and medical wire device of the present invention>
FIG. 1 is a preferred embodiment of the present invention.

  The medical wire in this example is basically a metal wire main body 2 and a short rod-like or string-like shape provided by connecting the rear end to the front end of the wire main body 2 and cut by heating. The connection member 3 and an in-vivo indwelling member 4 provided to be connected to the distal end portion of the connection member 3.

  The illustrated guide wire 1 is used as an inductor (extrusion means) for introducing the in-vivo indwelling portion 4 into a target site. The guide wire 1 includes a wire body 2 in which a resin coating layer is formed on an outer peripheral surface of a wire serving as a core, and a distal contrast portion 7 that follows the wire body 2. Here, the outer diameter of the guide wire 1 is 0.1 to 2.0 mm, for example, and the length of the guide wire 1 is 0.1 to 2.0 m, for example. As a wire which becomes the core which comprises the guide wire 1, what consists of electroconductive materials, such as stainless steel, can be used.

  The wire body 2 in the illustrated example has a proximal side portion 5 having an insulating coating formed on the surface thereof, a flexible portion 6 following the proximal side portion 5, and a distal contrast portion 7 connected to the flexible portion 6. Thus, the connection member 3 is connected to the distal end portion of the distal contrast enhancement portion 7.

  The flexible portion 6 and the distal contrast portion 7 of the wire body 2 are configured such that, for example, a winding wire is further densely wound in a coil shape on the outer peripheral surface of a wire serving as a core. Here, the outer diameter of the wire body 2 is preferably 0.1 to 2.0 mm. Moreover, the length of the wire main body 2 is made into various length according to the objective, for example, is 0.1-1.8 m. As the wire constituting the wire body 2, for example, a conductive material such as stainless steel can be used, and for the distal contrast portion 7, a wire made of an X-ray contrast metal such as platinum, silver, or tungsten is used. Can do.

  The distal contrast portion 7 of the guide wire 2 has a configuration in which a winding wire is further tightly wound in a coil shape on the outer peripheral surface of the core wire. As the winding wire constituting the distal contrast portion 7, a wire made of a metal such as platinum, silver, or tungsten can be used.

  The surface insulating coating on the proximal portion 5 of the wire body 2 can be formed of an appropriate material, but can be usually provided by coating various resins such as a fluororesin and a hydrophilic resin. When the surface insulating coating is made of a fluororesin, it is preferable in that the friction coefficient of the surface of the wire body 2 can be reduced.

  The outer end portion of the hand side portion 5 has a wire portion exposed to form a terminal portion 8 through which electric power is passed through an appropriate conductive member such as an electric connector, a plug, or a clip. Supply is possible. The length of the terminal portion 8 is sufficient if it is about 1 to 3 cm, for example.

  The connecting member 3 is made of a water-swellable material and is formed in a rod shape or a string shape as a whole.

As the water-swellable material forming the connection member 3, it does not adversely affect the living body, has an appropriate water-swelling property, and the connection member-forming substance is dissolved and cut by heating in a state containing water, Any device can be used as long as the in-vivo indwelling member 4 is detached therefrom. Specific examples thereof include polyvinyl alcohol polymers such as polyvinyl alcohol (PVA), PVA cross-linked polymer, PVA water-absorbing gel freeze-thaw elastomer, ethylene vinyl alcohol copolymer, polyhydroxymethacrylate, polyacrylic acid, poly Sodium acrylate, polyacrylamide, poly-N-vinylpyrrolidone, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polyglycolic acid, methyl vinyl ether maleic anhydride copolymer, polyhydroxyethyl phthalate ester, polydimethylol propionate ester, Synthetic polymer materials such as methyl isopropyl ketone formaldehyde, polyethyleneimine, polystyrene sulfonate, water-soluble nylon; carboxymethyl starch, dial Hidodenpun, celluloses (CMC, MC, HEC, HPC), tannins, lignin, it can be alginic acid, gum arabic, guar gum, gum tragacanth, gelatin, casein, glue, be mentioned natural high molecular substances such as collagen. Of these, polyvinyl alcohol polymers are preferred from the viewpoints of safety to the living body and dissolution rate. Further, from the viewpoint of exerting an appropriate swelling property when contacted with water, the average degree of polymerization of the polyvinyl alcohol polymer is preferably 500 to 7000, and more preferably 1500 to 4000. If the average degree of polymerization is less than this range, the strength decreases, which is not preferable. The saponification degree of the polyvinyl alcohol polymer is preferably 98 mol% or more from the viewpoint of moldability.
The average polymerization degree and saponification degree here are measured according to JIS K6726.

  In addition to these, it is also possible to use a polyamide resin, a polyester resin, or the like having water swellability.

  The water-swellable material constituting the connection member 3 is, for example, a method of spinning a melt of water-swellable material by extrusion or stretching, a water-swellable material having fluidity or a solution of the water-swellable material in a coagulating liquid. It can be obtained by a method of spinning while extruding and solidifying, or other methods. Moreover, what is obtained by performing post-processing, such as an extending | stretching process, to the filament obtained by such a method can also be used.

As water-soluble salts to be included in the connection member, metal halides, carbonates, sulfates, nitrates, chlorates, and so on that do not adversely affect the living body and have a solubility in water at 25 ° C of 10 wt% or more Salts such as chlorite, acetate, carboxylate and phosphate are used, and these may have crystal water. If the solubility is less than 10 [wt%], the salts are not sufficiently eluted when the connecting member swells, and the swelling / dissolution rate of the connecting member decreases, which is not preferable.
The solubility may be 100 [wt%] or less from the viewpoint of stability against moisture absorption during medical wire storage.
The method for measuring the solubility in water at 25 ° C. is based on the method described in WELinke, “Solubilities of Inorganic and Metal-Organic Compounds” 4th Eddition (D. Van Norstrand).
From the viewpoint of safety and solubility in the living body, such salts are preferably sodium chloride, potassium chloride, sodium sulfate, sodium nitrate, barium sulfate, sodium nitrate, sodium carbonate, calcium phosphate and hydrates thereof. These may be used alone or in combination of two or more.

  The amount of water-soluble salts contained in the connecting member is preferably in the range of 1 to 25% by weight, more preferably 1 to 15%, and still more preferably 2 to 10%. If the amount of the water-soluble salt is larger than this range, the tensile strength of the connecting member is lowered, and the risk that the in-vivo indwelling member falls off other than the target site is not preferable. The time required for swelling increases, which is not preferable.

  The method for containing a water-soluble salt in the water-swellable material of the connecting member is not particularly limited, but a method of drying after molding by coexisting the water-soluble salt in the aqueous solution of the water-swellable material of the connecting member, A method in which the water-swellable material is swelled with an aqueous solution of a water-soluble salt after molding and then dried can be used.

  The range of the shape of the connecting member 3 is not particularly defined. The outer diameter of the connecting portion 3 varies depending on the specific configurations of the wire body 2 and the in-vivo indwelling member 4, as long as the target in-vivo indwelling member 4 can be connected to the wire body 2 by appropriate means. Good. For example, the distal contrast portion 7 and the in-vivo indwelling member 4 are both coil bodies, and in an example of the connection member 3 used in a state where both ends are inserted into the coil body and connected, the outer diameter is, for example, It is preferable that it is 0.05-2.0 mm and length is 1.0-10 mm. Further, in order to obtain a sufficient swelling speed and dissolution rate at the time of heating, the connecting member 3 may be an aggregate of fibrous body elements or may have a shape in which grooves or irregularities are provided on the surface.

  The rear end portion of the connection member 3 is connected and fixed to the front end portion of the wire body 2. The connection means is not particularly limited, and for example, adhesion by an adhesive, welding, connection by physical force, or other means can be used. Of these, adhesion by an adhesive is particularly preferable. In this case, for example, a cyanoacrylate adhesive can be suitably used as the adhesive.

  The in-vivo indwelling member 4 in the present invention includes a coil body or an embolization member other than the coil body, a drug-containing capsule that is indwelled and gradually releases the drug, an embolization member such as a balloon that closes the annular organ, and other indwelling members Therefore, an appropriate member having a medical action or a medical auxiliary action can be used.

  An example of the in-vivo indwelling member 4 of the present invention is a coil body used as an embolization member. As such a coil body, in the present invention, for example, a double coil body made of an elastic material having variable shape can be preferably used. Specifically, it is a double coil body made of, for example, a platinum alloy and wound by winding a wire having a diameter of 0.05 to 0.10 mm, and its primary coil diameter is 0.1 to 1.. One having a diameter of 0 mm and a secondary coil diameter of 2 to 30 mm can be preferably used. Such an in-vivo indwelling member 4 can carry or hold an appropriate substance.

  As another example, an in-vivo indwelling member in which the same hydrophilic resin as that of the connecting member 3 is formed into a rod shape can be used. This may be formed separately from the connection member 3 or may be formed integrally as a part of the connection member 3. The rod-shaped in-vivo indwelling member can contain a drug such as a blood coagulation promoting substance. According to the in-vivo indwelling member containing the blood coagulation promoting substance, the formation of a thrombus is promoted in the aneurysm embolized by the in-vivo indwelling member, and an excellent embolization effect can be exhibited. Examples of the blood coagulation promoting substance include thrombin, fibrinogen, fibronectin, protease and the like. Further, the rod-shaped in-vivo indwelling member may contain a substance having a contrast property (hereinafter also simply referred to as “contrast agent”). According to the embolic material containing the contrast agent, the dynamics of the embolic material introduced into the target site can be monitored by the contrast device. Examples of such contrast agents include substances exhibiting an X-ray contrast effect such as tungsten, bismuth oxide, barium sulfate, platinum, gold, and silver. The outer diameter of the embolic material is preferably 0.1 to 0.5 mm in the non-swelled outer diameter (d), preferably 0.2 to 1.0 mm in the swollen outer diameter (D), The increase rate [(D / d-1) × 100] is preferably 10 to 300%, more preferably 50 to 100%. According to the embolization material made of a swellable resin having an increase rate of the outer diameter of 10% or more, a further excellent embolization effect can be exhibited by expanding the diameter in contact with blood or the like at the application site. The length of the embolic material can be appropriately adjusted according to the volume of the application site (in the aneurysm), but is usually about 1 to 500 mm, preferably about 5 to 100 mm.

  The in-vivo indwelling member 4 is provided by being connected to the distal end portion of the connection member 3. The connection means is appropriately selected from the various means described above as the connection means between the connection member 3 and the wire body 2. Can be used.

  The resin coating layer disclosed in JP-A-11-47138 can be formed on the wire body 2 of the guide wire 1 by coating the outer peripheral surface of the core wire with, for example, a fluororesin or a hydrophilic resin. When this resin coating layer consists of a fluororesin or hydrophilic resin, it is preferable at the point which can make the friction coefficient of the surface small. The outer end of the wire body 2 is formed with a terminal portion 8 in which the core wire is exposed. Via the terminal portion 8, an appropriate conductive member such as an electrical connector, a plug, or a clip is provided. Electric power can be supplied. It is sufficient that the length of the terminal portion 8 is about 1 to 3 cm.

  Moreover, an electrically insulating film can be provided on the outer peripheral surface of the wire body. This electrically insulating film can be formed of various polymers such as polyurethane, fluororesin, polyethylene, polypropylene, silicone resin, polyamide resin such as nylon. However, a hydrophilic resin may be further applied to the outer surface of the resin coating.

  The medical wire having the above configuration is used by the method exemplified in Japanese Patent Laid-Open No. 2000-229086. At this time, first, before the insertion into the living body, the swelling treatment is performed on the connecting member 3 of the medical wire. This swelling process is performed by immersing the portion of the connecting member 3 of the medical wire in an appropriate swelling water.

  Thus, in the above medical wire, since the connecting member 3 is formed of a water-swellable material containing a water-soluble salt, the swelling speed is high and a large amount of water can be connected to the connecting member 3 in a short time. It will be absorbed and contained in the water-swellable material that constitutes it. Therefore, a sufficient swelling process can be achieved in a very short time. In particular, when the outer diameter of the connection member 3 is as small as 150 μm or less, there may be a case where sufficient swelling treatment can be performed simply by passing the connection member 3 through the swelling water.

  Here, the swelling water is not particularly limited as long as it is not harmful to the living body. For example, physiological saline, pure water, ultrapure water, ion exchange water, an aqueous solution of a compound such as dimethyl sulfoxide, blood, etc. Can be used.

  The immersion time for the swelling treatment varies depending on the combination of the water-swellable material and the water-soluble salt that form the connection member 3, but usually it may be as short as 0.1 to 100 seconds, preferably 3 seconds or less. It is. The medical wire subjected to the swelling treatment is introduced into the living body through an appropriate catheter as shown in FIG. Specifically, as shown in FIG. 2, the catheter 10 is inserted into the living body 9 by a normal method, and the distal end of the catheter 10 is a place where the in-vivo indwelling member 4 is to be placed, in this example, the place of a cerebral aneurysm. P is reached. Reference numeral 11 denotes a hand operating portion of the catheter 10. As this catheter 10, for example, a microcatheter can be used.

  The medical wire is inserted into the catheter 10 from the hand operating section 11 with the in-vivo indwelling member 4 as the head. Then, the ground electrode 12 is attached to an appropriate skin surface of the living body 10, the high frequency power supply device 13 is connected to the terminal portion 8 of the wire body 2, and a monopolar high frequency current is supplied to the wire body 2. The monopolar high-frequency current preferably has a frequency of about 0.2 to 5 MHz and a power of about 0.1 to 5 W, for example. One current supply, time is 1 to 10 seconds, for example.

  By such an operation, the electrolyte solution (blood) at the distal end of the wire body 2 is self-heated by the high-frequency current and becomes high temperature, and the connection member 3 is heated, thereby melting and cutting the connection member. The in-vivo indwelling member 4 is detached from the wire body 2, whereby the indwelling of the thrombus-forming member made of the coil body is achieved.

  However, according to the medical wire described above, as described above, a sufficient swollen state is achieved in the swelling treatment by forming the cross-sectional shape of the detached portion of the connecting member 3 within the scope of the present invention. Therefore, for example, the connection member 3 can be surely cut by a single operation of supplying a cutting current, and therefore the intended indwelling member can be placed in a short time and reliably. And high reliability can be obtained. In addition, since the swelling process is completed in a short time, the entire time required for the indwelling of the in-vivo indwelling member can be made extremely short.

  Specifically, when the water-swellable material constituting the connecting member 3 is made of a polyvinyl alcohol polymer or copolymer, for example, it is ensured by supplying a high-frequency current for a very short time within 1 second. The connecting member 3 can be detached. Therefore, the burden on not only the operator but also the living body to be operated becomes very light.

  Moreover, since the wire main body 2 has electroconductivity, the connection member 3 can be reliably heated by supplying, for example, a monopolar high-frequency current through the wire main body 2 using the wire main body 2. . Therefore, in this case, it is not necessary to provide a lead wire that reaches the connecting member 3. Therefore, the operability is high and there is no possibility that the lead wire is broken. Therefore, even when pulling back in order to correct the position of the in-vivo indwelling member 4 once arranged, the operation can be surely executed, so that high reliability can be obtained.

  Although the embodiments of the present invention have been specifically described above, various modifications can be made in the present invention. For example, a variety of in-vivo indwelling members 4 can be used. Specifically, a coil body or an embolus-forming member other than the coil body, a medicine-containing capsule that is placed and gradually releases the medicine, a tubular organ An embolization member such as a balloon that closes the body, or any other member having a medical action or a medical auxiliary action by other placement can be used.

  Moreover, an electrically insulating coating can be provided on the outer peripheral surface of the wire body. This electrically insulating coating can be formed of various polymers such as polyurethane resin, fluororesin, polyethylene, polypropylene, silicone resin, polyamide resin such as nylon, etc., and a hydrophilic polymer is further formed on the outer surface of the resin coating. It can also be applied. And according to such a medical wire, by supplying a monopolar high-frequency current through the wire body as described above, the in-vivo indwelling member can be detached and placed, but the living body tissue of the wire body Since the surface of the part that comes into contact with the skin is covered with an electrically insulating coating, it is possible to prevent adverse effects on the tissue, so that it is not necessary to use a catheter in the operation of insertion and placement in the living body. It becomes.

  In the present invention, the means for cutting the connection member is not limited to means for supplying a monopolar high-frequency current via a conductive wire body. For example, the electrode provided on the outer peripheral surface of the connection member or the distal end of the catheter Means for supplying a monopolar high-frequency current to a counter electrode provided on the living body via a lead wire to the electrode provided at the position of the opening, between a pair of electrodes provided apart from each other on the outer peripheral surface of the connection member A means for supplying a bipolar high-frequency current via a lead wire, a means for supplying a bipolar high-frequency current between a pair of electrodes provided at the position of the distal end of the catheter, and other means can be used.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by this.
<Example 1>
(1) An aqueous solution of 20% by weight of polyvinyl alcohol having an average degree of polymerization of 2000 and a degree of saponification of 98%, and 5% by weight of sodium chloride is extruded into ethanol, which is a coagulation liquid, and spun. A connecting member made of polyvinyl alcohol having an outer diameter of 0.12 [mm] and an average degree of polymerization of 90000 was produced by performing a stretching process up to 4 times over 3 minutes at a constant speed in% air. The connecting member had an outer diameter of 0.12 mm and a length of 5.0 mm.
(2) Fabrication of medical wire According to the configuration shown in FIG. 1, a 0.08 mm diameter winding is densely wound around a 0.05 mm diameter tapered core wire to make a stainless steel with an outer diameter of 0.4 mm and a total length of 1800 mm. The wire body 11 is prepared, and the rear end portion of the connecting member 15 made of the knitted assembly is adhered to the front end portion thereof with an adhesive made of cyanoacrylate. An adhesive made of cyanoacrylate is used as a base end portion of the in-vivo indwelling member 16 made of a double coil body having a primary coil diameter of 0.3 mm and a secondary coil diameter of 3 to 12 mm. Was bonded to produce a medical wire.
(3) Detachment experiment A swelling treatment was performed by immersing the portion of the connecting member of the medical wire obtained as described above in physiological saline for 1 second. A stainless steel container is equipped with a ground electrode and filled with physiological saline, and a microcatheter having an outer diameter of 1 mm and a total length of 1500 mm is fixed to the container so that its tip is immersed in physiological saline. Then, the medical wire is introduced from the hand operating part outside the container of the microcatheter with the in-vivo indwelling member 4 as the head, and is advanced until the connecting member 3 reaches the position of the tip opening of the microcatheter. As a result, in the container, the in-vivo indwelling member 4 was completely restored to a double coil body having an initial form.
In this state, the output terminal of the high frequency power supply device is connected to the terminal portion 25 at the rear end on the proximal side of the wire body 2 with a cord, and a high frequency current having a frequency of 300 kHz and a power of about 0.5 to 0.6 W is supplied for 5 seconds. When the operation was performed once, the connecting member was instantaneously cut and the in-vivo indwelling member was detached.
<Example 2> (1) An aqueous solution of 20% by weight of polyvinyl alcohol having an average degree of polymerization of 2800 and a saponification degree of 98% and 1% by weight of sodium chloride was sealed in a cylindrical mold having an inner diameter of 0.6 mm, and then -25 A molded body obtained after 20 times of freezing treatment at 10 ° C. and thawing treatment at 10 ° C. was taken out and taken out three times in the longitudinal direction. The outer diameter was 0.15 mm and the length was A connecting member having a thickness of 5.0 mm was produced.
(2) Production and separation experiment of medical wire A medical wire was produced in the same manner as in Example 1 except that this connecting member was used. When this medical wire was used to conduct a cutting experiment in the same manner as in Experimental Example 1, the connecting member was instantaneously cut and the in-vivo indwelling member was detached.
<Comparative Example 1> An aqueous solution of 20% by weight of polyvinyl alcohol having an average degree of polymerization of 2000 and a degree of saponification of 98% was extruded and spun into ethanol, a coagulation liquid, and the resulting filament was in air at 23 ° C and 50% humidity Then, a connecting member having an outer diameter of 0.12 [mm] was manufactured by performing a stretching process up to 4 times over 3 minutes at a constant speed. This connecting member was a connecting member having an outer diameter of 0.12 mm and a length of 5.0 mm. Except that this connection member was used, a medical wire was prepared in the same manner as in Example 1, subjected to the same swelling treatment, and a similar detachment experiment was performed. Depending on the operation, the connecting member could not be cut, and it was necessary to supply a high-frequency current three times before the in-vivo indwelling member was released.
<Comparative Example 2> In Comparative Experimental Example 1, when the same experiment was repeated by gradually increasing the immersion time in the physiological saline in the swelling treatment, the connection member was cut by one supply of cutting current. It was confirmed that the immersion time in physiological saline was required to be 3 minutes or longer.

It is explanatory drawing which shows the structure of one Embodiment of the medical wire apparatus of this invention. It is explanatory drawing which shows an example of the usage method of the medical wire apparatus of this invention. It is explanatory drawing which shows an example of the usage method of the medical wire apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Guide wire 2 Wire body 3 Connection member 4 In-vivo indwelling member 5 Hand side part 6 Flexible part 7 Tip contrast part 8 Terminal part 9 Living body 10 Catheter 11 Hand operation part 12 Ground electrode 13 High frequency power supply device

Claims (3)

It consists of a wire body and an in-vivo indwelling member connected to the tip of the wire body via a connecting member made of a water-swellable material, and the connecting member is heated and cut by supplying a cutting current. In this case, in the medical wire having an in-vivo indwelling member, the water-swellable material is a polyvinyl alcohol polymer having an average degree of polymerization of 500 to 7000. And the connecting member contains 1 to 25% by weight of a water-soluble salt. The water-soluble salts are metal halides, carbonates, sulfates, nitrates, chlorates, hypochlorites, acetates, carboxylates, and phosphoric acids having a solubility in water of 10 wt% or more. further comprising, medical wire according to claim 1, wherein the at least one selected from the group consisting of salts. Water-soluble salts, sodium chloride, potassium chloride, further comprises sodium sulfate, sodium nitrate, barium sulfate, sodium nitrate, sodium carbonate, and that at least one selected from the group consisting of calcium phosphate, according to claim 1 or medical wire according to 2.

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