DE19610333A1 - Apparatus and process for introduction and release of implant in vivo - Google Patents

Abstract

Process and apparatus for introducing and releasing an implant (5) in the human body, especially a blood vessel (8) or body cavity, by means of an insertion aid, especially a guide wire (1), to the end of which an implant is attached, are new. The implant is glued to the insertion aid by means of a special plastic and is positioned at the target site. The implant is released by passing a current from the end of the insertion aid (13) via the implant and the body fluids to a counter-electrode (14), whereby the plastic bond is broken or dissolved.

Description

Genus and information on the genus

The invention relates to a method and an apparatus for introducing a Implants in the human body and for the rapid detachment of this implant tels electrical current according to the features in the preamble of claim 1.

The endovascular treatment of vascular diseases in the human body is a form of therapy with growing importance. So far, catheters have been used to various treatment materials, implants and medications in veins and arteries in the human body. Examples of such implants and their uses can be found in U.S. patents: U.S. Pat. 52 34 437, U.S. Pat. 51 22 136, U.S. Pat. 51 08 407, U.S. Pat. 53 50 397, U.S. Pat. 52 50 071 and U.S. Pat. 53 54 295. The The arrangements described there are generally used for this, so-called aneurysms - Blood vessels sagging - through the endovascular insertion of small emboli to close station spirals. This form of therapy is particularly important for not operable aneurysms such as B. in the brain. Closure of the aneurysm is said to be a danger enlargement or bleeding. The closure of fistula connections between arteries and veins, from veins that supply such fistulas, as well as from fistulä The proportions of arteriovenous malformations of the brain and spinal cord represent a wide range res area of application of the arrangements for introducing embolization spirals.

State of the art

In the U.S. Pat. 53 50 397, U.S. Pat. 52 34 437 and U.S. Pat. 52 50 071 is described ben, such as the insertion of an embolization spiral in the body defects described above by means of a micro-catheter. In this micro catheter a thin, torsional stiff wire inserted at the tip of which is an embolization coil. In these three patents describe how an embolization coil can be used by different me mechanical constructions are attached to the wire end. The replacement of the embolization Spiral occurs through another wire, which is pulled or pressed thereby the mechanical connection opens and the spiral is released. The transfer times  these systems are relatively short, but the mechanical connection is either which is rigid and thus impedes implant placement, or the implant can be er no longer retract the end of the micro-catheter end, since the embolization spiral immediately is replaced. Furthermore, exact positioning is often difficult because the embolisa tion spirals only poorly or not at all by turning the wire into the desired one Get orientation.

In U.S. Pat. 51 22 136, U.S. Pat. 53 54 295, WO 91/13592, WO 93/16650, WO 95/12367 and WO 96/00034 describe how the detachment of such an emboli Sation spiral is carried out electrolytically. A thin wire is inserted into the micro catheter at the top is an embolization spiral. This embolization spiral is there attached to the wire tip by means of a solder connection. The replacement of this embolisa tion spiral is carried out electrolytically. The wire is connected to the positive Pole of a voltage source and the patient's body connected to the negative pole sen. The voltage source now ensures a current flow of generally 1 mA. This Current flow leads to the electrolytic dissolution of the wire tip, which comes from the micro catheter protrudes. This will detach the embolization coil and implant it. Disadvantageous are in this process, the long separation times compared to mechanical separation as well as the foreign matter particles and ions arising in the electrolysis, such as. B. Chrome and nickel, which are distributed through the existing bloodstream and / or allergic re can trigger actions. The very good flexibility and positionability is an advantage this device.

In recent times (U.S. Pat. 51 08 407), attempts have also been made to laser ab solve such an embolization spiral. The advantage of this system is that comparatively short peeling time and the firm mechanical connection of the embolization spiral with the introductory system. Due to the high effort involved in the implementation Such a detachment system has so far not yet been commercially available. After The risk of accidental vascular injuries due to a malfunction continues placed laser pulse. This could lead to the patient's death.  

The invention is therefore based on the object of a method and an apparatus create for the insertion of an implant into the human body and rapid detachment the implant from the insertion aid. In particular, it should be possible to have a Embolization coil into a blood vessel or body cavity after correct positioning detachment from a wire without freeing harmful foreign substances or particles can be placed and get into the surrounding vascular system.

This object is achieved by the characterizing features of the patent claim 1 solved.

Detailed description

The basic idea of the invention is the detachment of an implant in human Body from an insertion aid by opening and / or releasing a plastic connection place by means of electric current. The following in particular are used as implants understood: spirals made of metal, such as. B. platinum or a platinum alloy, which is a primary and May have secondary winding; Spirals made of radiopaque plastic, implants, that can temporarily release medication; Implants that have local radiation enable by encapsulated radioactive materials; Implants that are supportive and hold open effect for vessels.

The method is described below using a device for detaching egg ner embolization coil (claim 21) made of a platinum alloy with primary and secondary winding as an implant, using a thin, torsionally rigid wire as an insertion aid, e.g. B. introduced into an aneurysm and detached there.

The embolization coil is attached to the distal end using a plastic connection point of the wire, and the embolization coil is then inserted endo vascular by a micro-catheter, the end of which is located in the aneurysm to be treated is. Using the thin, torsionally rigid wire, the embolization spiral is Micro catheter pushed until it emerges at the end and is located in the aneurism. There it is first correctly positioned by pulling and turning the wire and loosens there the embolization process of the surrounding blood. After that, the wire placed on the negative potential of a voltage source, the positive potential of which the skin or in the body of the patient to be treated. By creating one Voltage of 0.5 to 10 V, a current flows through the wire to  Plastic junction, to the embolization coil and back through the body fluid speed to the outer counter electrode. This creates hydrogen bubbles at the wire end and at the embolization spiral. These hydrogen bubbles now promote according to claim 13 Embolization of the surrounding blood. The current flow ensures according to claim 10 and 11th of the invention for the replacement and / or dissolution of the plastic junction from Wire and the embolization coil. The resulting hydrogen bubbles practice you Pressure in the plastic and especially at its connection points to the metallic wire and implant and thus create a stretching effect on the plastic composite location. In contrast to electrolytic detachment, in which a metallic wire atomically resolved by a reduction process takes place here through the influence of Hydrogen a macroscopic detachment and / or dissolution takes place. After detachment the embolization spiral and the successful embolization of the aneurysm becomes the The wire and the micro-catheter are withdrawn again and removed from the vascular system distant. Under certain circumstances, not just one but several embolization spirals are required be introduced to ensure successful embolization of the aneurysm.

A major advantage of the method described is that the release time by Selection of a suitable plastic compared to the electrolytic peel off into the Seconds range (5 to 30 seconds) can be reduced. It is also advantageous that the Removal process no toxic and / or allergic substances arise. The mechanical Flexibility of the device is also not affected, which is the introduction of the Implant easier compared to mechanical detachment arrangements. The implant Compared to electrolytic peeling, it has no wire tips, which are more necessary there arise wisely and can damage the surrounding tissue. Instead, can the implant should be designed so that there is only one blunt or rounded end and any tissue injury can be excluded.

The insertion aid must be designed so flexibly that the introduction of an im plantates is made possible by strongly tortuous vessels, and a positioning of the Im plantates in the target area by turning and pushing. The plastic connector body must therefore be designed so that it the mechanical load of the introduction of the Withstand implants and their positioning in the target area.

As a torsionally rigid element according to claims 14 to 16 elements made of steel, Mo lybdenum or quartz can be used. If a quartz element is used, it must be used for  electrical contact to the connection point. This can e.g. B. according to An Say 16 take place by means of a wire which is passed through a quartz capillary. The egg ne end of the wire is connected to the negative pole of the voltage source, and to the other end, protruding from the quartz capillaries, is the implant by means of attached to the plastic junction.

The detachment process at the plastic connection point is crucial from the suitable choice of the plastic and its processing influences. According to claim 2 the removal process is accelerated by the fact that the plastic absorbs water particularly strongly men, and thus the formation of hydrogen bubbles at the metallic interfaces of the Plastic is promoted to the implant or insertion aid. This is e.g. B. at Polydi methylsiloxane the case. Since the implant to be detached may be a Long-term implant acts, as described in claim 3, a corresponding body tolerance is given. It is particularly advantageous if the connection point is made of egg nem absorbable plastic is produced (claim 4), since it cannot be excluded, that under certain circumstances particles of plastic in the detachment process into the surrounding Tissue or the surrounding fluid, such as B. blood. Now for the Plastic connection point the necessary properties such as high water absorption ver like, absorbability, body tolerance, sufficient strength and good processing To optimize availability, it may be advantageous according to claim 5, a copolymer to use.

A wide variety of mechani are used to attach the implant to the insertion aid training of the implant end to be fastened and the insertion aid end conceivable. In a preferred device, the end of an embolization spiral with a provided open spiral, the inner diameter is selected so that the wire end one has a slightly smaller diameter. This open spiral is then ge on the wire end slide and finally attached there with the plastic (claim 22). Furthermore, it can be advantageous, the plastic connection point from all sides for the surrounding medi to make it easily accessible to speed up the peeling process. This can e.g. B. according to claim 23 by an expansion of the embolization spiral end, so that the Embolization spiral has a larger slope there. Since it cannot be ruled out that The implant is no longer mechanically stable on the insertion aid when detached, but nevertheless due to the existing static friction during the withdrawal on the  Insertion aid remains, it is advantageous according to claim 25, the detachment process by a ge support suitable mechanical device. This can e.g. B. as in claim 26 be wrote to be a barb that clings to the shell of the micro-catheter when pulled back remains and thus allows stripping of the embolization coil. According to claim 27 3, the end of the embolization spiral can be a stretched part for realizing art have a material connection point and an unstretched spiral part. Against this unstretched Spiral presses a spring spiral, which is attached to the distal end of the insertion aid. This overcomes the static friction that may occur during the detachment process. It is the same possible to provide the implant with a round end and there the end of the insertion help, which in this case is designed as a spiral spring, to be attached by means of the plastic (Claims 28 and 29). To realize a mechanical resistance here, the Diameter of the implant end slightly larger than the inside diameter of the flexible Mi be krokatheders, so that when the implant is withdrawn after the current has flowed slight resistance occurs which causes the implant to detach.

In the following, the invention is based on drawings that are not to scale clarifies and exemplified.

Fig. 1 shows a torsionally rigid wire as an insertion aid for an attached at the tip th embolization coil.

FIG. 2 shows schematically the device for detaching the embolization spiral from FIG. 1, after positioning in an aneurysm by means of a microcatheter.

Fig. 3 shows schematically the pulling out of the micro-catheter and the insertion aid after detaching the embolization coil and embolization in the aneurysm.

Fig. 4 shows an embolization coil at the end of which there is a plastic connection point in which the wire end of the insertion aid is inserted.

Fig. 5 shows the connection point of an embolization coil on a wire by means of three spiral windings, which are wrapped tightly and with a large pitch around the wire end and surrounded by the plastic.

FIG. 6 shows a connection point similar to FIG. 5 with the difference that there is still a barb at the end of the narrow spiral.

FIG. 7 shows a device similar to FIG. 5 with the difference that here a spiral with a larger diameter is connected to the narrow spiral.

FIG. 8 shows a device similar to FIG. 7, with the difference that a second spiral under tension is also used.

Fig. 9 shows an embolization coil, at the end of a metallic ball is det, which is attached by means of a plastic at the end of the insertion aid spiral.

In Fig. 1 an enlarged side view of the distal end of a torsionally rigid wire ( 1 ) can be seen. This wire has a diameter of approximately 0.1 to 0.5 mm, the wire tapering at the distal end in area ( 2 ) in order to ensure greater flexibility. This tapered area is typically 10 to 40 cm long and ends with a thin tip ( 3 ). The entire length of the wire is 40 to 300 cm, depending on the application. A so-called embolization spiral ( 5 ) is now axially attached to the wire tip ( 3 ) by means of a plastic connection point ( 4 ). It is advantageous to manufacture this embolization spiral from a radiopaque and body-compatible material. It is therefore convenient to use platinum or platinum alloys to make this embolization coil. This embolization coil has a diameter of approximately 0.2 to 1.5 mm and has a rounded end ( 6 ). This rounding prevents puncturing of the aneurysm into which the coil is inserted. It is advantageous if the platinum spiral has a secondary winding in the form of a helix, since this makes it easier to fill in the aneurysm. The platinum spiral wound in this way has an elongated length of approximately 5 to 50 cm. The diameter of the secondary winding is approximately 3 to 20 mm.

Fig. 2 now schematically shows how the device of Fig. 1 is introduced through a Mikroka theder ( 7 ) into the vascular system through a blood vessel ( 8 ). This Mikroka theder has an inner diameter of 0.2 to 1.5 mm. The end of the micro-catheter ( 9 ) is localized so that it extends into the aneurysm ( 10 ) to be closed. At the end of the micro-catheter ( 9 ), the distal end ( 3 ) of the wire ( 1 ) emerges with the embolization spiral ( 5 ) fastened there. The plastic connection point is so angeord net that it is outside of the micro-catheter in the surrounding blood. The embolization spiral now fills part of the aneurysm and the detachment process can be started. For this purpose, a voltage source ( 12 ) with its negative pole on the wire ( 1 ) is connected (13) and the positive pole by means of a counter electrode on the patient ( 14 ). After the embolization of the blood in the aneurysm ( 11 ) and the detachment of the wire tip ( 3 ) by the current flow from the voltage source ( 12 ), the wire ( 1 ) and the microcat ( 7 ) can now be pulled out of the blood vessel ( 8 ) ( Fig. 3). The embolization spiral ( 5 ) with the plastic connection point ( 4 ) is now in the aneurysm ( 10 ) and 5 ensures permanent closure.

The simplest design of the plastic connection ( 4 ) between the wire tip ( 3 ) and the embolization coil ( 5 ) is shown in Fig. 4. The wire tip ( 3 ) is in the plastic ( 15 ), which in turn is placed at one end of the embolization coil ( 5 ).

A preferred embodiment of the plastic connection point ( 4 ) is shown in FIG. 5. The wire tip ( 3 ) ends in a platinum spiral ( 16 ) whose inner diameter is designed such that the wire tip ( 3 ) is closely enclosed by the platinum wire. The actual embolization coil connects to this platinum coil ( 16 ). The slope of the platinum spiral ( 16 ) is chosen so that a space is created in the middle of the individual turns. This inter mediate space is filled with the selected plastic ( 15 ) and thus joins the wire ( 1 ) and the embolization coil ( 5 ).

For better detachment of the embolization spiral, it can be provided with a kind of barb ( 17 ) (see Fig. 6). This barb overcomes the retraction of the wire ( 1 ) the static friction that may occur between the detached plastic ( 15 ) and the wire tip ( 3 ). The barb ( 17 ) remains on the distal end ( 19 ) of the micro-catheter ( 7 ) and thus creates a mechanical resistance that is large enough to overcome the static friction. The barb ( 17 ) is preferably made from the end of the platinum spiral ( 16 ). This has the advantage that no additional joining of two components is necessary, and that the wire is soft enough to allow the embolization coil ( 5 ) to be retracted, if necessary. The barb ( 17 ) has a rounded end ( 18 ) to prevent accidental puncturing of the tissue. It is also advantageous to manufacture the barb ( 17 ) from a quasi-elastic alloy so that repeated pulling of the barb ( 17 ) into the distal end of the microcathedral ( 19 ) is possible without the barb ( 17 ) bending irreversibly.

The end of the platinum spiral ( 16 ), as shown in FIG. 7, can also merge into a platinum spiral with a larger diameter ( 20 ) instead of a barb. The diameter is chosen so that it corresponds approximately to the diameter of the distal end of the microcathedral ( 19 ) and is therefore likely to get stuck on the microcathedral end ( 19 ) when withdrawn. This resistance overcomes the static friction that may occur in the separation process.

FIG. 8 shows a device similar to FIG. 7, with the following differences: the platinum spiral ( 20 ) has the same diameter as the embolization spiral ( 5 ); a second spring coil ( 21 ) under tension is used, which overcomes any static friction that may occur. The tensioned spring spiral ( 21 ) is fastened to the wire ( 1 ) by means of a connection point ( 22 ). Has the plastic connection point ( 4 ) loosened after the detachment process, the second, tensioned spring coil ( 21 ) separates the implant from the insertion aid ( 1 ) through its relaxation and the associated extension.

Another preferred embodiment is shown in FIG. 9. At the end of the embolization coil ( 5 ) there is a metallic ball ( 23 ). This is attached to a metallic spiral ( 24 ) by means of the plastic, which is located at the wire tip ( 3 ) and is conductively connected to it ( 25 ). The distal end of the micro-catheter ( 19 ) is preferably performed so that it tapers conically at the end ( 26 ). The inside diameter is chosen so that the embolization coil does not experience any mechanical resistance when it emerges into the aneurysm. The ball ( 23 ), on the other hand, has a diameter which is somewhat larger than this, so that mechanical resistance occurs when the ball is pulled out or pulled in through the tapered distal end ( 26 ) of the microcatheder ( 7 ). This mechanical resistance helps to overcome the static friction that may occur when detaching the embolization coil ( 5 ).

Furthermore, a large number of other exemplary embodiments are conceivable, but not here can be fully described. It is essential for these exemplary embodiments but the use of a plastic connection point between the implant and the insertion help that can be quickly replaced by electrical current in the human body can.

Reference list

1 torsionally rigid wire
2 tapered area of ( 1 )
3 thin wire tip at the distal end of ( 1 )
4 plastic connection point between ( 3 ) and ( 5 )
5 embolization coil
6 rounded end of ( 5 )
7 micro catheters
8 blood vessel
9 end portion of ( 7 )
10 aneurysm (bulge of 8 )
11 embolized blood in ( 10 )
12 voltage source
13 contact of the cathode from ( 12 ) to ( 1 )
14 Contact of the anode from ( 12 ) to the patient
15 plastic of ( 4 )
16 platinum spiral at the connection point to ( 3 )
17 barbs at the end of ( 16 )
18 rounded end of ( 17 )
19 end of ( 7 )
20 platinum end spiral from ( 16 )
21 coil spring under tension
22 junction of ( 21 ) with ( 1 )
23 metallic ball at the junction of ( 5 )
24 metallic spiral at the end of ( 3 )
25 conductive connection from ( 3 ) to ( 24 )
26 tapered end of ( 19 )

Claims (29)

1. Method and device for inserting and detaching an implant ( 5 ) into the human body, in particular into a blood vessel ( 8 ) or a body cavity, by means of an insertion aid, in particular a so-called guide wire ( 1 ), at the end of which an implant ( 5 ) is attached, characterized in that

• (a) the implant ( 5 ) is glued to the insertion aid using a special plastic ( 15 ) and positioned in the implant target;
• (b) the implant ( 5 ) is detached by a current flow from the end of the insertion aid ( 13 ) and from the implant ( 5 ) via the body fluid to the counterelectrode ( 14 ) which detaches and / or dissolves the plastic connection point ( 4 ).

2. The method and device according to claim 1 are characterized in that the plastic ( 15 ) absorbs water particularly strongly. 3. The method and device according to claim 1 are characterized in that the plastic ( 15 ) is tolerated by the body. 4. The method and device according to claim 1 are characterized in that the plastic ( 15 ) can be absorbed by the body. 5. The method and device according to claim 1 are characterized in that in particular the following plastics ( 15 ) can be used at the connection point ( 4 ): cellulose, polyamides, polydimethylsiloxane, polyester, polyethylene, polyethylene terephthalate, polyether urethane, polyimide, polylactide, polymethyl methacrylate, polyoxymethylene , Polypropylene, polyurethane, water-absorbing and / or porous plastics or mixed polymer from the plastics mentioned. 6. The method and device according to claim 1 are characterized in that the current flow of the voltage source ( 12 ) via the electrodes ( 13 and 14 ) is selected so that it does not affect the health of the patient and is usually 0.001 to 10 mA. 7. The method and device according to claim 1 are characterized in that the insertion aid ( 1 ) is at the cathodic potential ( 13 ) and the counter electrode ( 14 ) at the anodic potential of the voltage source ( 12 ) used. 8. The method and device according to claim 1 are characterized in that the potentials of the insertion aid ( 1 ) and the counter electrode ( 14 ) are alternately at anodic and cathodic potential of the voltage source ( 12 ) used. 9. The method and device according to claim 1 are characterized in that the voltage source ( 12 ) enables a controllable temporal change in potential. 10. The method and device according to claim 1 are characterized in that by the current flow at the insertion aid ( 1 ) and on the implant ( 5 ) and in and on the plastic ( 15 ), which are connected as a cathode, hydrogen bubbles are formed, which detach the Contribute to the implant. 11. The method and device according to claim 1 are characterized in that the plastic used ( 15 ) can also be macroscopically resolved by the current flow during the detachment process. 12. The method and device according to claim 1 are characterized in that the release time is a function of the plastic properties and the thickness of the plastic ( 15 ) at the connection point ( 4 ). 13. The method and device according to claim 1 are characterized in that the hydrogen bubbles generated on the implant ( 5 ) have a thrombogenic effect on the blood surrounding them. 14. The method and device according to claim 1 are characterized in that the insertion aid ( 1 ) is a thin, torsionally rigid element. 15. The method and device according to claim 14 are characterized in that the torsionally rigid element is a wire made of steel, molybdenum or quartz. 16. The method and device according to claim 15 are characterized in that the torsionally rigid element ( 1 ) made of quartz has a thin capillary in which a wire can be inserted. 17. The method and device according to claim 1 are characterized in that the implant can be a thrombogenic, radiopaque plastic. 18. The method and device according to claim 1 are characterized in that the implant can temporarily release medication. 19. The method and device according to claim 1 are characterized in that the implant receives local radiation from encapsulated radioactive materials can enable.   20. The method and device according to claim 1 are characterized in that the implant can have a supporting and open effect for vessels. 21. The method and device according to claim 1 are characterized in that the implant is an embolization spiral ( 5 ), ie a spiral made of metal, such as. B. platinum or a platinum alloy, which may have a primary and secondary winding. 22. The method and device according to claim 21 are characterized in that the wire of the embolization coil can be wrapped around the insertion aid. 23. The method and device according to claim 21 are characterized in that the turns of the end of the embolization coil can be stretched. 24. The method and device according to claim 21 are characterized in that the tip of the insertion aid ( 3 ) can have a smaller diameter than the embolization coil ( 5 ). 25. The method and device according to claim 1 are characterized in that the detachment of the implant ( 5 ) from the insertion aid ( 1 ) can be supported by a suitable mechanical device. 26. The method and device according to claim 25 are characterized in that this mechanical device is a barb ( 17 ) which is located on the implant. 27. The method and device according to claim 25 are characterized in that this mechanical device is a spiral spring ( 20 ) which is located on the implant ( 5 ), which is replaced by a second tensioned spiral spring ( 21 ). 28. The method and device according to claim 1 are characterized in that the end of the insertion aid ( 3 ) is designed in the form of a spiral spring ( 24 ) to which the implant ( 5 ) is fastened by means of the plastic. 29. The method and device according to claim 28 are characterized in that the implant end ( 23 ) is rounded.