DE4333910A1 - Guide wire for medical instruments and method for its manufacture - Google Patents

Abstract

The invention relates to a guide wire for medical instruments, in particular for simultaneous insertion with a catheter or a puncture needle, consisting of a generally cylindrical, flexible core wire and wires which pass helically round the core wire and, in turn, are surrounded by a usually cylindrical sheathing which is coaxial with the core wire, said core wire (2) ending with a slight axial spacing from the proximal and possibly distal end (5) of the guide wire (1) formed by the sheathing (4), and the end face of the wires (3) adjacent to the proximal and possibly the distal end generally having an even greater spacing, compared to the above, from the end (5) of the guide wire (1). The invention also relates to a method for the manufacture of such a guide wire. <IMAGE>

Description

The invention relates to a guide wire for medical technology, especially for simultaneous Push in with a catheter or a puncture onsnadel, consisting of a usually zylin bendable, flexible core wire, as well as the core wire helically encircling wires, which in turn from a usually cylindrical, to the core wire coaxial sheathing are surrounded as well as a ver drive to manufacture.

Guide wires can be found in different areas Medical use to avoid size rer operations from diagnostic or therapeutic reasons, measuring probes, surgical instruments or medication in a body to be treated, primarily introducing organs or cavities. Basically, between two procedures for Introduction and exact positioning of a guide wire distinction:

The first, also under the name "Seldinger method" known method is the Guide wire under simultaneous observation the X-ray screen inserted into the body and kor positioned right. Then a catheter slid over the guide wire and for injection of drugs or the like, for measuring blood pressure  or to insert a surgical instrument used.

In the second procedure, for example in An giography, i.e. the radiological vessel position of arteries is used first a sharp puncture needle or a Ka theter together with that arranged inside Guide wire in the examined or to be acting vessel introduced. Because of the higher mechanical stability of the needle and catheter is an exact positioning even without simultaneous X-ray possible.

A generic guide wire is from WO 85 01 444 known; it consists of a cylindrical Core wire screwed from a sheath en-shaped wires and an outer wire tig arranged plastic layer is surrounded. At its tip is to avoid unwanted, potentially life threatening injuries from Vascular and blood vessels opened an end cap puts.

DE-GM 85 15 986 also describes one a cylindrical core wire with a wire sheath tion as well as a plastic jacket guidewire, which at its proximal end with a attached top tip made of plastic is.

The conventional guide wires have in common that them in operations according to both of the above  Methods can be used. Since in particular the sel dinger process high demands on a leader guidewire - it must bend and be insensitive to shearing and high flexibility act with sufficient stability to allow a small bend radius and it to be able to advance on the other are the Her cost of the usual guide wires due to complex manufacturing processes relatively high.

It is therefore considered disadvantageous that the Surgery costs not least due to the expensive, for hygienic reasons usually only ver design high reversible guide wires and that they also with catheter or puncture surgery come into use, although then theirs share properties due to the surrounding In principle, catheters and needles are not required are.

The inventor is based on the state of the art based on the problem, especially for simultaneous insertion with a catheter or egg suitable puncture needle create, which was significantly reduced by Manufacturing costs.

According to the invention, the problem is solved by that the core wire at a small axial distance from the proximal formed by the sheath and possibly the distal end of the guide wire det and the proximal and possibly the distal  Usually, the adjacent end of the wires end an even greater distance from the end of the guide wire.

The main idea of the invention is that end tips to be manufactured separately neller guide wires through the end of the actual Chen wrapping to replace. The guidewire is in a manner known per se from a rule cylindrical, flexible core wire, the core wire helical circumferential wires, and one coaxial to the core wire, surrounding the wires casing built. The core wire ends at the proxima len and, if desired, at the distal end in one small axial distance from that of the material the sheathing existing face of the Füh guidewire, so that on the one hand also physiologically questionable materials for the core wire for ver can come to turn, on the other hand to the Verhin necessary unwanted tissue injuries Elasticity, especially of the proximal end, ge remains guaranteed. To the guide wire with a flexible tip relative to its remaining length and a good one in the beginning To achieve flexibility, those of the proximal end and possibly adjacent the distal end face usually, helically wound wires already at a greater distance from the completion of the Guide wire.

The main advantages of the invention are in that the guide wire due to the Einspa rens a separate end cap cheaper  is adjustable. Because of the use of a core wire with helical circumferential, for ver strengthening and stiffening wires so like both the guidewire and the him surrounding tissue protecting, coaxial sheathing the mechanical properties are the conventional nellen guide wires at least equivalent, so that the latter with a catheter or one Operations performed by the puncture needle inventive, cheaper guide wire he are settable.

The material of the sheathing is in the concrete FEP or recommended polyurethane mixed with 20% BaSO Polyureth len. The plastic FEP is a copolymer made of Tetrafluoroethylene and hexafluoropylene and is suitable is good for steam sterilization. The sliding dough properties of the plastic are made of polyurethane the addition of barium sulfate (BaSO₄) improved. Further advantages of the proposed materials be are in particular for endoscopy significant, high dielectric constant as well in that they are also opposed to torsion bela proving resistant. The lubricity the guide wire can be replaced by a hydrophilic action of the sheath significantly improved become.

It is an ideal starting material for the core wire primarily inexpensive, rust-free Fe derstahl on. However, there is an alternative ity, durable and versatile usable use mory metal.  

The number of wires circulating around the core wire is any within the scope of the inventive idea. In concrete terms, it turns out to be useful, 3 or 7 or use 12 or 19 wires.

The task, an inexpensive process to create a guide wire, is solved according to the invention in that the umman telung near the proximal and possibly di stalen end of the guidewire in a ring cut and peeled off their frontal part will, with the exception of the wires now exposed cut off the core wire near the incision the core wire is shortened and possibly sharpened and the stripped casing again over the Core wire pushed in and with the rest of the sheath and welded round at the tip.

The main idea is to wrap the jacket nes helically wrapped core with wires wire near the proximal (and possibly the in the distal end and cut their deduct the frontal section, the exposed helical wires near the incision cut off and finally like the sheath to put on the core wire and with the rest around the sheathing and at the tip welding. After the front of the jacket is removed, the protruding end of the core wire be sharpened to re the guide wire designed to prevent buckling. Farther the core wire is shortened so that the actual  Tip of the guide wire through the relatively flexi ble sheathing is formed and an unintended penetration of vessel walls due to the deforming tip is prevented. The abge pulled, finally over the core wire again pushed part of the sheathing is final Round welded on the face to the guide wire to seal to the outside and also by a Round weld connection on the rest of the casing attached.

The advantages of the method according to the invention stand in particular in that few work steps are required so that the guide wire in a significantly reduced time and price values can be produced. Furthermore, only conventional machinery and equipment required; high investment costs for special devices are unnecessary. The source material of the Ver driving, a helically wrapped with wires The covered core wire is already commercial available.

In addition to the welded joint it turns out to be the fixie tion of the peeled part of the casing Adhesive connection to the guide wire, d. H. the protruding part of the core wire and the forehead side of the remaining casing, as an advantage arrested.

To avoid unwanted injuries during surgery at the tip of the guidewire  To avoid tissue, it is recommended to hemispherical or to be welded conically.

A j-shaped bend in the end portion of the core wire has an improvement in leadership which hollow organs to the advantageous result.

The casing can be replaced by a continuous Ex trusion process on the helical wires be applied as a preference, that an unwanted chipping of the casing not to be feared even with higher loads is.

The production of the guidewire is designed particularly inexpensive, if one is of greater length manufactured guide wire to the desired shortened axial dimensions and then at least least at the proximal end after the proposed one Method is topped.

To cut the exposed wires to it lighter, lends itself first to the core wire to handle.

Finally, it is suggested that the exposed, protruding end of the core wire by electropo rejuvenation. Its protruding face is connected to an electrode and in an elec Trolyt bath immersed. The second electrode ent speaks the walls of the ge with the electrolyte bath filled vessel. Through a the core wire as well the current flowing through the electrolyte bath becomes successive  sive material from core wire into the electrolyte bath transferred and the latter rejuvenated. Since the - to mas Removal proportional - density of the wire from the Electrolyte bath current due to the electrical resistance of the wire increase the distance from the electrode decreases a sharpening of the end facing the electrode of the core wire.

Further details, features and advantages of the Er can be found in the following description Take part of the exercise, in which the drawings Embodiments of the invention explained in more detail become. They show a schematic representation in

Fig. 1, the proximal end of a guide wire with a tapered core wire,

Figure 2 shows the proximal end of wire. Of a guide wire with a flattened end face of the core,

Fig. 3 shows the proximal end of a core wire with a j-shaped tip.

The principle in its construction of a core wire (2), it helically circumferential cords (3) and a coaxial to the core wire (2) sheath (4) existing, shown in FIG. 1 guide wire (1) is at its proximal end (5) with a rounded, hemispherical tip. The core wire ( 2 ) is tapered and ends at a distance from the end of the guide wire ( 1 ) formed by the envelope ( 4 ). The helically wound wires ( 3 ) are cut at a distance from the proximal end ( 5 ) near the ring-shaped incision ( 6 ) which is larger than the end of the core wire ( 2 ). The latter is introduced during the manufacture of the tip and makes it possible to pull off part of the sheath, to sharpen the core wire ( 2 ) and to shorten the screw-shaped wires ( 3 ). The cut-off, frontal part of the sheathing ( 4 ) is welded to the incision ( 6 ) with the rest of the sheathing ( 4 ) and fastened to the core wire ( 2 ) by an adhesive connection.

The basic structure of the guide wire shown in Fig. 2 Darge ( 1 ) corresponds to that shown in Fi gur 1 . In contrast, the end face of the core wire ( 2 ) is just cut abge and the end face of the wires ( 3 ) is arranged in the immediate vicinity of the core wire ( 2 ).

Finally, a guide wire ( 1 ) is shown in Fig. 3, the end ( 5 ) of which is bent in a J-shape. The core wire ( 2 ) and the helical circumference of the wires ( 3 ) are cut straight and end in the straight part of the end of the guide wire ( 1 ) consisting of the material of the sheath ( 4 ).

The result is a guidewire that yourself by price and a simple man distinguishing procedure.

Claims (13)

1. Guide wire for medical technology, in particular for simultaneous insertion with a catheter or a puncture needle, consisting of a generally cylindrical, flexible core wire, and the core wire helically surrounding wires, which in turn are surrounded by a usually cylindrical, coaxial to the core wire sheath , characterized in that the core wire ( 2 ) ends at a small axial distance from the proximal and possibly dis tal end ( 5 ) of the guide wire ( 1 ) formed by the casing ( 4 ), and that the proximal and possibly the The distal end of the adjacent end face of the wires ( 3 ) is generally at an even greater distance from the end ( 5 ) of the guide wire ( 1 ). 2. Guide wire according to claim 1, characterized in that the sheath ( 4 ) is FEP or with 20% BaSO₄ mixed polyurethane. 3. Guide wire according to claim 1 or 2, characterized in that the sheath ( 4 ) is coated hydrophilically. 4. Guide wire according to one of claims 1 to 3, characterized in that the core wire ( 2 ) is made of stainless spring steel or memory metal. 5. Guide wire according to one of claims 1 to 4, characterized in that the core wire ( 2 ) is wrapped with 3 or 7 or 12 or 19 wires. 6. A method for producing a guide wire according to one of claims 1 to 5, in which a core wire is helically wrapped with wires and then provided with a sheath, characterized in that the sheath ( 4 ) in the vicinity of the proximal ( 5th ) and possibly the distal end of the guidewire ( 1 ) is cut into a ring and its end part is pulled off,
that the now exposed wires ( 3 ) with the exception of the core wire ( 2 ) near the incision ( 6 ) are cut off,
that the core wire ( 2 ) is shortened and possibly pointed and
that the stripped sheathing ( 4 ) is pushed back over the core wire ( 2 ) and is welded to the rest of the sheathing ( 4 ) and at the tip. 7. The method according to claim 6, characterized in that the stripped casing ( 4 ) is glued to the guide wire ( 1 ) before welding. 8. The method according to claim 6 or 7, characterized ge indicates that the tip is hemispherical or cone is welded in a shape. 9. The method according to any one of claims 6 to 8, characterized in that the end region of the core wire ( 2 ) is bent in a J-shape. 10. The method according to any one of claims 6 to 9, characterized in that the casing ( 4 ) is extruded. 11. The method according to any one of claims 6 to 10, characterized in that a longer guide wire ( 1 ) is shortened to the desired axial dimensions. 12. The method according to any one of claims 6 to 11, characterized in that the exposed wires ( 3 ) are unwound from the core wire ( 2 ) before cutting. 13. The method according to any one of claims 6 to 12, characterized in that the core wire ( 2 ) at least at its proximal end ( 5 ) is tapered by electro-polishing by its end to be tapered ( 5 ) is connected to an electrode, the core wire ( 2 ) is immersed in an electrolyte bath, which is located in a housing, on the walls of which external electrodes are attached.