Electrodes for electrosurgical handheld instruments, and electrosurgical handheld instruments

Abstract

To provide an electrode for an electric surgical handheld tool having a high chemical resistance and a high thermal resistance.SOLUTION: An electrode (10) for an electric surgical handheld tool substantially includes a conductive wire, where the wire is coupled to an electrode support body (14) of the handheld tool at both ends (25, 26) thereof. The wire is composed of at least two different types of materials. In this case, a first material has a first fusion temperature, and a second material has a second fusion temperature. The second fusion temperature is higher than the first fusion temperature.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrode for an electrosurgical hand-held instrument and an electrosurgical hand-held instrument.

Background Art

[0002] Electrosurgical hand-held instruments of a correspondingly attributive type, especially resectoscopes, are used in electrosurgical procedures, particularly in urology. In that case, these electrosurgical hand-held instruments are typically used for the resection and evaporation of tissue, for example, tissue of the lower urinary tract. For this purpose, an electrosurgical hand-held instrument, especially a resectoscope, can have a longitudinally displaceable electrode support that can push the distal working end forward from the distal end of the instrument shaft of the electrosurgical hand-held instrument after insertion of the electrosurgical hand-held instrument into the body to be treated. An electrosurgical electrode is arranged at the distal end of the electrode support. This electrode can, for example, have the form of a loop and can be pulled or pushed through the tissue to manipulate the tissue depending on the structural form of the electrosurgical hand-held instrument.

[0003] In the above applications, a high-frequency current is applied to the electrode. Known electrodes for this high-frequency surgery are made of homogeneous metal. In that case, they are distinguished into two groups, namely, electrodes made of high-melting-point metals such as, for example, tungsten, and electrodes made of noble metals such as, for example, platinum or platinum alloys. The advantage of using an electrode made of a metal with a high melting temperature is that it functions reliably even at high temperatures and does not break or change its shape. However, electrodes made of tungsten in particular have low reliability against chemical loads, which shortens the life of the electrodes. This has proven to be disadvantageous especially when using plasma.

[0004] In contrast, precious metals possess this chemical resistance, but on the other hand, they have a lower melting point than, for example, tungsten, which can be a disadvantage, especially in situations where higher current densities are reached. For example, during a patient procedure, an electrode to which a high-frequency voltage is applied may come close to a conductive implant present in the patient's body. If a spark discharge occurs, a high current will be generated, which could lead to the platinum electrode melting or changing shape to the point where it needs to be replaced. Therefore, currently, there are two common shapes of electrodes, and since both have advantages and disadvantages, there is no ideal electrode without the aforementioned drawbacks. [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of the present invention is to provide electrodes for electrosurgical handheld instruments and electrosurgical handheld instruments having high chemical resistance and high temperature resistance. [Means for solving the problem]

[0006] A solution to this problem is provided by the features of claim 1, which is intended to provide an electrode for an electrosurgical handheld instrument, such as a resectoscope, which is substantially made of a conductive wire (hereinafter referred to as the wire), and which is coupled at both ends to an electrode support of an electrosurgical handheld instrument (hereinafter referred to as the handheld instrument). The wire is made of at least two different types of materials, in which case a first material, one of these materials, has a first melting temperature, and a second material has a second melting temperature, the second being higher than the first. These different properties or melting temperatures of at least two materials can solve the above problem. This configuration makes it possible to provide an electrode that is chemically stable and at the same time has high current resistance, i.e., remains mechanically stable even at high current densities.

[0007] Another advantageous exemplary embodiment of the present invention involves a first material having plasma resistance or a first standard potential, and a second material having plasma resistance or a second standard potential. In this case, according to the present invention, the first standard potential is intended to be greater than the second standard potential. Thus, the plasma resistance or standard potential of the materials behaves in opposite ways to each other, as do the melting temperatures of the two materials. This choice of materials is another possibility for providing electrodes that are chemically stable and simultaneously have high current resistance.

[0008] A preferred embodiment of the present invention may involve a second material forming the wire core and a first material forming an outer layer surrounding the core, or a first material forming the wire core and a second material forming an outer layer surrounding the core. By arranging the two materials in this manner, it is possible to achieve, on the one hand, that the electrode is chemically stable to the outside, and on the other hand, that its shape does not change even at high temperatures. Therefore, different embodiments of the electrode can be used depending on the application or requirements.

[0009] Another possible exemplary embodiment of the present invention may be envisioned in which the wire is constructed like a skin from multiple layers of a first material and a second material, the first and second materials surrounding each other, and the core of the wire is formed from either the first or second material. This onion-like structure of the electrode can achieve, so to speak, high chemical stability of the electrode, and at the same time, high temperature resistance.

[0010] Furthermore, according to the present invention, a wire core layer structure consisting of at least two first and second materials can be intended to extend along the entire length of the wire. This electrode configuration is particularly advantageous when manufacturing the wire from two components because it can be manufactured inexpensively and in large quantities. For example, one material of a tube may be surrounded by the other material, or the corresponding material may be deposited. Other manufacturing possibilities are also conceivable.

[0011] An advantageous exemplary embodiment of the present invention may be envisioned in which the wire comprises at least two segments, namely a first end segment and at least one central segment, the central segment being positioned on the first end segment, and the first end segment being connectable to an electrode support of a handheld instrument. This structural form of electrodes to different sections or parts makes it possible to achieve a particularly advantageous design that is chemically stable, heat-resistant, and inexpensive to manufacture.

[0012] In a particularly advantageous exemplary embodiment of the present invention, the wire may be composed of at least three segments, namely first and second end segments and at least one central segment, the central segment being positioned between the two first and second end segments, and the first and second end segments being connectable to an electrode support of a handheld instrument. This division of the electrode into different sections or parts makes it possible to achieve a particularly advantageous design that is chemically stable, heat-resistant, and inexpensive to manufacture.

[0013] In particular, the central section of the wire is intended to have a core made of a second material and an outer layer made of a first material surrounding the core, or a core made of a first material and an outer layer made of a second material surrounding the core. By limiting the first and second materials, and especially by limiting this special core layer structure to the central section, a considerable amount of material and, consequently, cost can be saved. This design limits the use of material to the area that actually comes into contact with tissue. The first and second end sections, which do not come into contact with tissue or plasma, or are not used to precisely manipulate tissue, can be made from other, less expensive, and easier-to-handle materials.

[0014] Preferably, the central section of the wire is constructed like a skin from multiple layers of a first material and a second material, with the first and second materials surrounding each other, and the core of the wire is formed from either the first or second material. This particular exemplary embodiment makes it possible to provide an electrode that is inexpensive to manufacture, chemically stable, and heat-resistant.

[0015] The first end piece, or the first and second end pieces, are made of a third material, and the ends of these end pieces are electrically, electrically, and mechanically connected to the central piece. One possibility for connecting the first and / or second end pieces to the central piece is bonding, welding, crimping, or crimping via a sleeve. This sleeve may also be welded to the two first and / or second end pieces, with the core according to the exemplary embodiment described above inside the sleeve. The connection possibilities mentioned herein provide an electrode that can be composed of multiple parts but has the required chemical and mechanical strength. In this exemplary embodiment of an electrode consisting of two or three separate parts, the central piece may be formed of a first or second material, and the sleeve may be formed complementaryly from a second or first material. Furthermore, in an embodiment of an electrode in which one of the first and second end pieces is electrically insulatingly connected to the central piece, this end piece may be made of an electrically insulating material.

[0016] The wires described herein may have a diameter of 0.2 mm to 1 mm, preferably 0.28 mm. Similarly, the wires may have different dimensions. Furthermore, the outer layer or sleeve surrounding the core may be intended to have a layer thickness of 3 μm to 0.2 mm, particularly 0.01 mm to 0.1 mm, preferably 0.05 mm.

[0017] It has been found that the first material is particularly advantageous to be platinum, or a platinum alloy such as platinum-iridium or platinum-tungsten. The second material can be tungsten, tantalum, or molybdenum. Finally, the third material may be steel or stainless steel, copper or a copper alloy, or an electrical insulator. It should be clearly noted that this list is not exhaustive, and rather, other materials with equivalent properties are intended to be used.

[0018] The electrosurgical handheld instrument for solving the above problems has the features of claim 18. According to this, this electrosurgical handheld instrument, which can be, for example, a resectoscope, is intended to have the electrode described in at least one of claims 1 to 17.

[0019] Preferred exemplary embodiments of the present invention will be described in more detail below based on the drawings.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram of an electrosurgical handheld device, particularly a resectoscope. [Figure 2] A side view of the electrode is shown. [Figure 3] A front view of the electrode according to FIG. 2 is shown. [Figure 4] A cross-sectional view of a first exemplary embodiment of the electrode is shown. [Figure 5] A cross-sectional view of another exemplary embodiment of the electrode is shown. [Figure 6] A cross-sectional view of another exemplary embodiment of the electrode is shown. [Figure 7] A side view of another exemplary embodiment of the electrode is shown. [Figure 8] A view of another exemplary embodiment of the electrode is shown.

Modes for Carrying Out the Invention

[0021] FIG. 1 shows a schematic side cross-sectional view of a resectoscope 10. The resectoscope 10 has a resectoscope shaft 11, and the resectoscope shaft 11 includes the shown outer shaft 12 or a covering tube. A tubular inner shaft 13 extends within the outer shaft 12. An electrode support 14 and the indicated optical system 15 are shown within the inner shaft 13. Further, other elements not shown here, such as a separate irrigation tube, etc., can be arranged in the resectoscope 10.

[0022] The electrode support 14 has an electrosurgical tool or electrode 16 at its distal end. The electrode 16 shown here is designed as a loop.

[0023] By operating the hand grip 19, the electrode support 14 can be moved axially in the distal and proximal directions while being forced to guide. In that case, the electrode support can be pushed out from the distal ends of the inner shaft 13 and the outer outer shaft 12. In this way, it becomes possible for the surgeon to operate on tissue further away from the tip of the resectoscope. For this purpose, the inner shaft 13 and / or the electrode support 14 can be supported so as to be rotatable about their respective longitudinal axes. A high-frequency current is applied to the electrode 16 to operate the tissue.

[0024] The resectoscope 10 shown in FIG. 1 has a passive transporter in which the carriage 20 is displaced distally against the spring force applied by the spring bridge 23 by the relative movement of the grip portions 21 and 22 disposed proximally to the resectoscope shaft 11 toward the first grip portion 21 at the distal end. When the carriage 20 is displaced distally toward the grip portion 21, the electrode support 14 is displaced distally in a manner not shown. When the hand grip portions 21 and 22 are released, the spring force generated by the spring bridge 23 forcibly returns the carriage 20 to its initial position, and the electrode support 14 is pulled in the proximal direction. When the carriage 20 is displaced and returned, an electrosurgical invasion by the electrode 16 can be performed passively, that is, without the force of the surgeon's hand.

[0025] For accurate treatment by the electrode 16, the optical system 15 is positioned so that the surgeon can optimally view the surgical area. For this purpose, the resectoscope 10 has an eyepiece 24 at its proximal end, and the eyepiece 24 is connected to the optical system 15. Alternatively, it is also conceivable that a camera is disposed in the resectoscope 10 instead of the eyepiece 24.

[0026] The electrode 16 described herein has a loop configuration. Such a loop structure is shown in a highly schematic manner in Figures 2 and 3. In this case, the wire is formed into a U-shaped loop so that both ends 25 and 26 can be electrically, and possibly mechanically, coupled to the electrode support 14 of the resectoscope 10. Coupling with the electrode support 14 is usually done by a plug connector. However, it should be clearly noted that other electrode configurations, such as button electrodes or needle electrodes, are also possible.

[0027] To ensure that the electrode 16 maintains its shape or is not damaged even at very high temperatures, i.e., at the high current densities that may occur when a high-frequency AC voltage is applied to the electrode 16, it is common to fabricate the wire or electrode 16 from tungsten. As is known, tungsten is characterized by its extremely high melting temperature. Similarly, it is necessary that the electrode 16 maintains dimensional stability against chemical reactions that may occur, especially in plasma applications, thereby allowing it to be used for as long as possible without performance degradation. This can be achieved by using platinum or a platinum alloy as the wire material. However, platinum does not have very high heat resistance and is very expensive.

[0028] The electrode 16 described herein consists of at least two different materials. Figure 4 shows a schematic cross-sectional view of a possible exemplary embodiment of the electrode 16. In this embodiment, the core 27 of the electrode 16 is formed of material M2 (second material), and the outer layer 28 surrounding the core 27 is formed of material M1 (first material). In this case, material M2 has a melting temperature T2 (second melting temperature), and material M1 has a melting temperature T1 (first melting temperature). A particularly preferred exemplary embodiment is intended in which temperature T2 is higher than temperature T1. Thus, material M2 can be a metal with a high melting temperature, such as tungsten, tantalum, or molybdenum. In contrast, material M1 can be a metal with a lower melting temperature, such as platinum, or a platinum alloy such as platinum-iridium or platinum-tungsten. This configuration gives the electrode 16 high chemical resistance to external influences and, at the same time, heat resistance to high current densities. Alternatively, for corresponding applications, the arrangement of materials M2 and M1 may be reversed. This is illustrated by the exemplary embodiment in Figure 5, where the outer layer 28 is formed of material M2 and the core 27 is formed of material M1.

[0029] Another possible exemplary embodiment of the present invention is shown in Figure 6, where a core 27 is the starting point and multiple consecutive layers 28 surround each other like the layers of an onion. Depending on the application or requirements, materials M1 and M2 can be arranged almost arbitrarily. For completeness only, it should be noted that it is also conceivable that more than two different materials may be used in this core layer structure.

[0030] In the exemplary embodiment described above, the core layer structure extends along the entire length of the wire, i.e., from end 25 to end 26. Typically, the length of this wire is 20 mm to 80 mm. The diameter of the wire can be 0.2 mm to 1 mm, preferably 0.28 mm, while the surrounding outer layer 28 can have a layer thickness of 3 μm to 0.2 mm, particularly 0.01 mm to 0.1 mm, preferably 0.05 mm.

[0031] Another exemplary embodiment of the electrode 16 is shown in Figures 7 and 8. The electrode shown therein consists of three sections or segments, namely a first end piece E1, a second end piece E2, and a central piece MST. The central piece MST is positioned between the two first end pieces E1 and the second end pieces E2. The two first end pieces E1 and the second end pieces E2 have two ends 25 and 26, to which these ends 25 and 26 can be coupled to the electrode support 14 as described above.

[0032] In one exemplary embodiment, the central piece MST of electrode 16 may be intended to have the same core layer structure as described above for other exemplary embodiments. Another exemplary embodiment is intended to be that the central piece MST is formed from material M1 or material M2. The first and second end pieces E1 and E2 are also made from steel or stainless steel, and as a result, a conductor made from tungsten, tantalum or molybdenum, or platinum alloy such as platinum-iridium or platinum-tungsten is present between the two first and second end pieces E1 and E2. To fix the central piece MST between the two first and second end pieces E1 and E2, the individual pieces may be bonded, welded, crimped or riveted together. In the exemplary embodiment shown in Figure 8, a sleeve 29 is at least partially positioned around the central piece MST and the two first and second end pieces E1 and E2. If the central piece MST is made from material M1, the sleeve 29 is made from material M2. In contrast, if the sleeve 29 is formed from material M1, the central piece MST is made of material M2. To attach the sleeve 29 to the first end piece E1 and the second end piece E2, it is conceivable to weld or crimp the sleeve 29 to the first end piece E1 and the second end piece E2. For this purpose, notches 30 are provided on the end piece of the sleeve 29, so that the aforementioned components of the electrode 16 are mechanically stable and electrically connected to each other. To ensure sufficient stability even under higher mechanical loads, it is also conceivable to weld the parts to each other and crimp them further. It should be explicitly noted that the dimensional setting and arrangement of the sleeve 29 may differ from those shown here merely as examples. Otherwise, the dimensions of the electrode 16 correspond to the values ​​above.

[0033] The last exemplary embodiment described integrates the advantages of cost-effective manufacturing, extremely high heat resistance, and chemical resistance to external influences acting on the electrode 16 during treatment. [Explanation of Symbols]

[0034] 10 Resectscope 11 Rejectscope Shaft 12 Outer shaft 13 Inner shaft 14 Electrode support 15 Optical system 16 electrodes 17 Guide Elements 18 Long axis 19 Hand Grips 20 Carriage 21 Grip section 22 Grip section 23 Spring Bridge 24 eyepieces 25 ends 26 ends 27 cores 28 layers 29 sleeves 30th increment M1 material M2 material E1 end piece E2 end piece MST center piece

Claims

1. An electrode for a handheld electrosurgical instrument, It is connectable at both ends to the electrode support of the electrosurgical handheld instrument and consists of a conductive wire made of at least two different types of materials, at least one first material having a first melting temperature and at least one second material having a second melting temperature. The second melting temperature is higher than the first melting temperature. The conductive wire is constructed like a skin from multiple layers of the first material and the second material, the first material and the second material surrounding each other, and the core of the conductive wire is an electrode for an electrosurgical handheld instrument formed from the first material or the second material.

2. The first material has plasma resistance or a first standard potential, The second material has plasma resistance or a second standard potential. The electrode for an electrosurgical handheld instrument according to claim 1, wherein the first standard potential is greater than the second standard potential.

3. The electrode for an electrosurgical handheld instrument according to claim 1, wherein the core layer structure of the conductive wire, comprising at least two of the first material and the second material, extends along the entire length of the conductive wire.

4. The electrode for an electrosurgical handheld instrument according to claim 1, wherein the end of the conductive wire is provided with a first end piece for coupling to the electrode support of the electrosurgical handheld instrument.

5. The electrode for an electrosurgical handheld instrument according to claim 1, wherein the conductive wire is provided with a first end piece and a second end piece for coupling to the electrode support of the electrosurgical handheld instrument, respectively.

6. The electrode for an electrosurgical handheld instrument according to claim 5, wherein the first end piece and the second end piece are formed from a third conductive or non-conductive material.

7. The electrode for an electrosurgical handheld instrument according to claim 5, wherein the first end piece and the second end piece are electrically and mechanically connected to the conductive wire at one of the ends of the first end piece and the second end piece, respectively.

8. Electrode for an electrosurgical handheld instrument according to claim 5, wherein one of the first and second end pieces is mechanically connected to the conductive wire at the ends of the first and second end pieces, respectively, and electrically insulated from the wire.

9. The electrode for an electrosurgical handheld instrument according to claim 7, wherein the first end piece and / or the second end piece are bonded, welded, crimped, fitted to the conductive wire, or crimped or welded via a sleeve.

10. The conductive wire has a diameter of 0.2 mm to 1 mm, and is an electrode for an electrosurgical handheld instrument according to claim 1.

11. The electrode for an electrosurgical handheld instrument according to claim 9, wherein the outer layer or sleeve surrounding the core of the conductive wire has a layer thickness of 3 μm to 0.2 mm.

12. The electrode for an electrosurgical handheld instrument according to claim 6, wherein the first material is a platinum alloy containing platinum-iridium or platinum-tungsten, and / or the second material is tungsten, tantalum, or molybdenum, and / or the third material is steel, stainless steel, or copper or copper alloy or an electrical insulator.

13. An electrosurgical handheld instrument comprising electrodes for an electrosurgical handheld instrument as described in claim 1.

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