Method

Abstract

To provide a method for manufacturing a counter support for an instrument improved in at least one point.SOLUTION: The method comprises the steps of providing a plastic injection mold 36 having an engraving 39 for arranging the frame 25 therein, arranging the frame 35 in the engraving 39, introducing plastic into the engraving 39 such that the plastic is in contact with the frame 25 and is in adhesive connection therewith, solidifying the plastic such that the plastic together with the frame 25 forms a counter support, opening the injection mold 36 and removing the counter support.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a countersupport for an electrosurgical instrument configured and suitable for cutting, or particularly for tissue fusion or coagulation in combination with tissue cutting. [Background technology]

[0002] Japanese Patent Publication No. 2004-180843 discloses a tissue coagulating and cutting instrument with two jaws in the form of forceps, movable relative to one another to hold tissue between them. An electric current can be applied to the two jaws to coagulate the tissue held between them. Furthermore, one of the jaws includes a cutting element to which an elastic counter-support is attached, located in the other jaw. Various configurations of the counter-support have been proposed. For example, the elastic counter-support can have a flat, T-shaped, square, solid cross-section, hollow cross-section, or stepped cross-section and can be inserted into a downwardly opening groove in the bottom jaw. This counter-support has a wider upper section facing the cutting element and a narrower section extending into the groove. During jaw closure, the counter-support deforms and fits into the groove. While the central section of the counter-support does not abut against anything, its edges are supported by steps extending along the central groove.

[0003] A coagulation and cutting instrument having a resilient counter-support is known from US Patent Application Publication No. 2004 / 0049185. The counter-support has a substantially square cross section and is supported opposite the cutting electrode between two legs of the jaws configured in a spaced apart U-shape. The sides of the counter-support are exposed.

[0004] U.S. Patent Application Publication No. 2009 / 0234355 discloses a coagulation and cutting instrument having a cutting electrode disposed in one jaw and a movably supported counter support disposed in the other jaw, the counter support being resiliently supported to avoid an intruding cutting electrode.

[0005] Further examples of electrosurgical instruments having a coagulation electrode, a cutting electrode and a counter support assigned to the cutting electrode can be taken from EP-A-1 632 192 and EP-A-2 754 403.

[0006] The requirements for coagulation and cutting instruments are increasing on several fronts: there is a trend towards miniaturization and a demand for manufacturing reliability and precision. Summary of the Invention [Problem to be solved by the invention]

[0007] Starting from this, it is an object of the present invention to provide a method for manufacturing a counter support for an instrument which is improved in at least one respect. [Means for solving the problem]

[0008] The method according to the invention as defined in claim 1 meets this objective.

[0009] The instrument according to the present invention comprises a cutting electrode on one jaw and a resilient counter support on the other, opposing jaw. The counter support is held in a frame provided by each jaw itself or a separate component. The counter support has a circumferential surface connected to the frame so as to withstand tension. The frame fixes the counter support on at least two opposing sides. Preferably, the frame has three sides, namely, two lateral sides and a distal side. The membrane surrounds the counter-support at its end. The counter-support is connected to the frame on at least two of its longitudinal sides or lateral surfaces, and optionally also at its distal end. In the latter case, the counter-support completely closes the frame, preventing material from entering the area below the counter-support. However, it is also possible for the membrane to be free at its distal end and / or its proximal end, i.e., detached from the frame.

[0010] The frame has a surface facing the counter-support that is connected to the circumferential surface of the counter-support. The connection is tension-resistant, i.e., a tension force directed from the edge of the counter-support toward its center does not release the counter-support from the frame. The connection is preferably gap-free, i.e., the circumferential surface of the counter-support is connected to the frame in a completely two-dimensional manner. Preferably, no part of the counter-support lifts off the frame in the event of a tensile stress. The cutting electrode, and possibly appropriate biological tissue present between the cutting electrode and the counter-support, can press against the counter-support during jaw closure, thereby generating a tensile force. This displaces the counter-support from its rest position and places it under tension. Since the counter-support is preferably flexible, tensile stress is thereby generated primarily due to deformation of the counter-support, which is why the counter-support is also referred to as a "membrane." In a preferred case, the counter-support is configured to be in a so-called membrane state, i.e., with respect to mechanical stress, the tensile stress present in the material of the counter-support is at least approximately equal everywhere, both in the unloaded state with the jaws open and in the loaded state, preferably with the jaws closed.

[0011] The tension-resistant connection between the countersupport and the frame is preferably a material-bonding connection, and if necessary, exclusively a material-bonding connection. This can be achieved simply by creating the membrane in an injection molding process, with the frame forming part of the injection mold, i.e., restricting the flow of material from the stationary liquid countersupport at the circumferential surface of the created countersupport. The frame is preferably made of metal. The countersupport is preferably made of flexible plastic, such as silicone plastic. The adhesion between the circumferential surface of the membrane and the frame can be increased by the respective surface design of the frame surface facing the membrane, for example, by roughening. Furthermore, the frame surface can be fully or partially activated to improve adhesion to the countersupport. For this purpose, the surface can be subjected to a CVD or PVD coating process, either locally or completely. If the frame is a punched component, the surface irregularities created during punching can be utilized to improve adhesion between the frame and the membrane.

[0012] The tension-resistant connection between the counter support and the frame can be supported by a form-fit between the counter support and the frame, for example, in that the frame includes form-fit structures, such as openings, notches, etc., along the surface facing the counter support.

[0013] Preferably, the counter-support is held in the frame without support. In particular, it does not abut the surface facing away from the cutting electrode's insertion direction. In other words, its free upper surface facing the cutting electrode is the same size as the free bottom surface of the counter-support facing away from the cutting electrode. As a result of this arrangement, the biological tissue held between the jaws is pressed particularly softly and uniformly against the cutting electrode, so that the tissue held between the cutting electrode and the counter-support is cut electrically but not mechanically. The separation process is purely electrical. This can be achieved in large instrument configurations as well as in miniaturized instrument configurations.

[0014] The counter support is preferably made of an electrically insulating plastic such as silicone. However, the counter support can also be made of a plastic that is intrinsically conductive or that is made extrinsically conductive, i.e., by embedding conductive substances or particles. This can create an additional thermal effect during the flow of current through the tissue.

[0015] Preferably, the opposing support comprises two sides arranged at a constant distance from each other, but the distance can also decrease in the distal direction.

[0016] The counter-support can have a thickness at its central section, which contacts the cutting electrode in the closed state, that is at most the same as the thickness of the edge of the counter-support. Preferably, the thickness of the central section is even smaller than that at the edge of the counter-support. This supports the main advantage of the present invention. During closure of the instrument, the counter-support is preferably stretched and not compressed or bent, as is often the case in the prior art. This also allows the membrane-like counter-support to conform well to uneven tissue and keep it in soft contact with the cutting electrode. However, it is also possible for the thickness of the counter-support in the center under the cutting electrode to be greater than that at the edge (side or circumferential surface).

[0017] The counter support can be domed away from or towards the cutting electrode in the rest position, allowing different spring characteristics to be adjusted to achieve a desired progression of tissue pressure against the cutting electrode during compression, i.e., closure of the device.

[0018] In an advantageous embodiment, the counter-support terminates flush with the frame on its upper side and its bottom side, which simplifies the manufacture of the device, and in particular the creation of the counter-support within the frame.

[0019] The counter support may comprise one or more sections extending over the frame. Preferably, such sections are located at the distal end of at least the counter support or the jaws that include the counter support. Such sections may function as spacers for the jaws and prevent the sections from coming into direct contact during closure. However, it is advantageous if, apart from these sections, the separate counter supports terminate flush with the frame at their top and bottom sides.

[0020] Further details of advantageous embodiments of the invention can be derived from the drawings, the associated description, and the claims. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 shows the device of the present invention in a closed state. [Figure 2] 2 is a cross-sectional view of the top and bottom jaws of the instrument according to FIG. 1 in an open state. [Figure 3] FIG. 3 shows the device according to FIGS. 1 and 2 in a closed state in cross section, without tissue. [Figure 4] 4 is a cross-sectional view of the instrument according to FIG. 3 with tissue held between the jaws. [Figure 5] FIG. 10 is a cross-sectional view of an alternative embodiment of the device in a slightly opened position. [Figure 6] FIG. 10 is a cross-sectional view of a further alternative embodiment of the instrument of the present invention with the jaws slightly open. [Figure 7] FIG. 7 is a partial perspective view of the bottom jaw of the instrument according to FIG. 6. [Figure 8] FIG. 6 shows a plastic injection mould for manufacturing the counter support of the device according to FIGS. 1 to 5. DETAILED DESCRIPTION OF THE INVENTION

[0022] 1 shows an instrument configured for fusing and cutting tissue. The instrument may be an open surgical instrument, a laparoscopic instrument, or an endoscopic instrument. The instrument 10 comprises jaws 12, 13, for example, held on a flexible shank 11 or a rigid shank, whereby at least one of the jaws, in this embodiment the upper jaw 12, is held on the other The jaws of the jaw 11 are pivotally supported so that they can move towards and away from each other, in this example the bottom jaw 13. Pivoting movement about the hinge axis A is controlled by a mechanism (not shown) which extends through the shank 11.

[0023] Alternatively, the instrument 10 may also include two pivotally supported jaws that are movable toward and away from each other.

[0024] 2 is a cross-sectional view of the instrument 10 according to FIG. 1 taken along line II-II in FIG. 1. For example, the upper jaw 12 can be made of a metal member 14 having a U-shaped cross-section, metallically exposed or electrically insulated on the outside, the leg surfaces 5 of which serve as coagulation electrodes 15, 16. The coagulation electrodes 15, 16 can be continuous strip-like electrodes or can be interrupted by insulating sections. Instead of the metal member 14, the upper jaw 12 can also comprise a separate member made of a non-conductive material, such as plastic, in which the coagulation electrodes 15, 16 are embedded, for example in the form of sheet members.

[0025] The upper jaw 12 is provided with a cutting electrode 17, which may comprise, for example, a thin metal sheet strip. Preferably, the cutting electrode 17 is held within an insulator 18 that is approximately centered between the coagulation electrodes 15, 16. The cutting electrode 17 is preferably positioned within an extension 19 of the insulator 18 so that the two flat sides of the cutting electrode 17 are insulated. Gaps 20, 21 are formed between the extension 19 and the legs of the upper jaw 12 that support the coagulation electrodes 15, 16 to aid in the location of tissue therein.

[0026] The bottom jaw 13 comprises a counter support 22 which serves to hold the tissue on the cutting electrode 17 during the cutting process. The counter support 22 is a flexible body, for example made of silicone, having a thickness D 12 measured in its central section 23, in particular in the extension of the cutting electrode 17. M is less than the width B measured across the counter support. The counter support 22 is made of a solid material and preferably does not contain any hollow space.

[0027] Laterally, the counter-support 22 adjoins the frame 25 with its circumferential surface 24 and is connected to the frame in the form of a material bond, preferably by overmolding or gluing, so as to withstand tension. The circumferential surface 24 is preferably unstructured, i.e., smooth, except for processing marks such as punches or fractures. However, the circumferential surface can also be configured to support a material connection between the counter-support 22 and the frame 25, for example by form-fitting.

[0028] The counter support 22 preferably has a thickness D of the central section 23. M a thickness D of the edge adjacent the circumferential surface 24 that is at least as great as R Furthermore, it includes the thickness D R corresponds to the thickness of the frame 25 measured in the same direction, so that the counter support 22 terminates flush with the frame 25 at its top side 26 and its bottom side 27.

[0029] The frame 25 is preferably made of metal so that its upper sides form the coagulation electrodes 28, 29. The coagulation electrodes can transition into each other at the distal end of the respective jaw 12 or 13.

[0030] The unit consisting of the counter support 22 and the frame 25 can be manufactured by an injection molding process, in which a pre-manufactured frame 25 is inserted into the respective injection mold, and then the plastic material of the counter support 22 is introduced into the mold so as to be intimately connected to the frame 25 at the circumferential surface 24. The unit thus produced is connected to the remaining load-bearing member of the bottom jaw 13, which in this embodiment consists of a U-shaped metal member 30. The unit can be metallically bare or electrically insulated. , for example, provided with a plastic coating on its outside. The frame 25 can also be bare metallic, i.e., conductive, or can be provided with an insulator on its outward-facing side. The frame 25 can be conductively connected to the metal member 30 or can be insulated from it. A gap 31 can be formed between the counter support 22 and the metal member 30, which can be isolated from the environment or connected to the environment by a suitable opening.

[0031] 3 shows the instrument 10 in a closed state. The electrodes 15, 28 are either in contact with each other or kept at a small distance from each other by spacers, not shown. The same is true for the coagulation electrodes 16, 29. The cutting electrode 17 stands upright on the counter support 22, forcing the counter support into the gap 31 without the bottom side 27 of the counter support 22 coming into contact with the metal member 30 or any other member present in the gap 31. The counter support 22 has a narrow cross section, i.e., a thickness D M Since the width B is significantly smaller than the width B, the counter support 22 is substantially in tension in the deformation shown in Figure 3. The counter support is stretched. Likewise, the connection between its circumferential surface 24 and the frame 25 is substantially in tension.

[0032] The device 10 operates as follows.

[0033] As shown in FIG. 4, for treatment of biological tissue 32, the biological tissue is first held between jaws 12 and 13. The biological tissue 32 can be organ tissue, blood vessels, or other tissue. Jaws 12 and 13 move toward each other to grasp the tissue 32. Simultaneously or sequentially, a coagulation voltage is applied to coagulation electrodes 15, 28, 16, and 29, and a cutting voltage is applied to cutting electrode 17. As shown in FIG. 2, counter support 22 moves past cutting electrode 17 during closure of instrument 10, thereby placing it under tension. However, the counter support thereby biases tissue 32 against cutting electrode 17. The biological tissue 32 can enter gaps 20 and 21 on either side of extension 19. Coagulation electrodes 15, 28, 16, and 29 coagulate the tissue held between them and, if it is a blood vessel, fuse the vessel, i.e., close the tissue at these locations. The tissue subjected to each higher cutting voltage by the cutting electrode 17 contracts and separates, thereby causing the opposing support 22 to hold the contracted tissue above the cutting electrode 17 .

[0034] The invention as described so far is susceptible to modifications. For example, as shown in FIG. 5, the counter-support 22 can be domed, convex towards the cutting electrode 17. As a result, during closing of the instrument 10, the dome of the counter-support 22 must first be overcome, which can result in a certain snap effect. Alternatively, the counter-support 22 can be completely planar. Apart from that, the description of FIGS. 1 to 4 applies correspondingly to the embodiment of the instrument 10 according to FIG. 5.

[0035] The counter support 22 can also be planar or concave, as in the embodiment according to Figures 1 to 4, i.e. configured in the shape of a dome moving away from the cutting electrode 17. With the progression of thickness from the center 23 towards the edge of the counter support 22, it is of course possible to adjust the desired spring characteristic of the dome, i.e. the progression of the path force that can be achieved during closure of the instrument 10.

[0036] In all of the above-described embodiments, counter support 22 may include extensions 33, 34, 35 that project above frame 25 and thus avoid direct contact between coagulation electrodes 15, 16 and 28, 29. However, also in this embodiment, counter support 22 preferably terminates flush with frame 25 at its top side 26 and its bottom side 27.

[0037] The manufacture of the counter support 22 will be explained with reference to Figure 8. For this purpose, a plastic injection mold 36 is provided between its top half 37 and its bottom half 38, and an engraving 39 is formed which defines the shape of the counter support to be manufactured. In the engraving 39, a central lifting projection 40 is shown in Figure 8, which reduces the thickness of the counter support 22 formed in the central section.

[0038] To manufacture the countersupport 22, the frame 25 is inserted into the engraving 39 while the plastic injection mold 36 is open, and then the injection mold 36 is closed. Liquid plastic is then filled into the engraving 39 so that it completely fills the provided space and abuts and adhesively bonds with the inside of the frame 25. After the plastic has hardened, the plastic injection mold 36 can be opened and the countersupport 22 can be removed.

[0039] In the inventive instrument 10, which can preferably be used for fusing and cutting tissue, a counter support 22 configured as a membrane is assigned to the cutting electrode 17, which is arranged between two electrode pairs. The membrane spans the frame 25 and is held thereon by a material bond at the circumferential surface of the frame, so that the circumferential surface extends at an angle, preferably perpendicular, to the coagulation electrodes 28, 29 formed by the upper frame parts. The compressive force exerted by the membrane, which presses the living tissue 32 against the cutting electrode 17, is therefore primarily generated by the tensile stresses present in the membrane. [Explanation of symbols]

[0040] 5. Leg surface of metal member 14 10. Equipment 11 Shank 12 Upper Jaw 13 Bottom Jaw 14 Metallic parts 15,16 Coagulation electrode of upper jaw 12 17 Cutting electrode 18 Insulators 19 Insulator extension 20,21 Gap 22 Opposing support 23 central section of opposing support 22 24 Circumferential surface of opposing support 25 frames 26 Upper side of opposing support 22 27 Bottom side of opposing support 28, 29 Coagulation electrode in bottom jaw 13 30 Metallic parts 31 Gap 32 Biological tissue 33-35 Extension 36 Plastic Injection Molds 37 Upper mold half 38 Bottom mold half 39 Engraving 40 Protrusion A Hinge axis D M Thickness measured within the central section of the opposing support D R Thickness of the opposing support at its edge

Claims

1. 1. A method for manufacturing an opposing support that is assigned to a cutting electrode arranged in one jaw of two jaws, at least one of which is supported so as to be movable towards and away from the other jaw, and that is arranged on the other jaw, comprising: providing a plastic injection mold having engravings for placing the frame therein; placing the frame within the engraving; introducing plastic into the engraving so that it contacts and adhesively connects with the frame; allowing the plastic to solidify so that it forms the opposing support with the frame; and c) opening the plastic injection mold and removing the counter support. method.

2. Further comprising the step of forming the frame as a stamped member. The method of claim 1.

3. Further, the method includes the step of activating the surface of the frame in whole or in part to improve adhesion of the counter support.

3. The method according to claim 1 or 2.

4. Further, the method includes the step of subjecting the surface of the frame to a CVD or PVD coating process. The method of claim 3.

5. The frame forms part of the plastic injection mold. The method according to any one of claims 1 to 4.

6. In the step of solidifying the plastic, the flow of the liquid plastic is restricted by the frame on the side of the created opposing support. The method of claim 5.

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