RU2808212C2 - Cutting electrode, surgical instrument and method of manufacturing cutting electrode - Google Patents

Abstract

FIELD: medical instruments.

SUBSTANCE: method of manufacturing a cutting electrode for a surgical instrument intended for connecting and cutting tissue, using a workpiece made of an electrically conductive material, includes making a programmed destruction site on the workpiece, dividing the workpiece into the first and second sections, placing the workpiece equipped with a programmed destruction site in a casting mold, which has a socket abutting the first portion and defining a cavity around the second portion, filling the mold with polymer to create a plastic body that encloses the second portion, opening the mold and removing the plastic body with the workpiece captured therein, and breaking the first portion from the second portion along the space programmed destruction. A cutting electrode for a surgical instrument and a surgical instrument for connecting and cutting tissue containing this cutting electrode are disclosed.

EFFECT: creating an electrode that provides energy savings.

15 cl, 10 dwg

Description

The invention relates to a method for producing a cutting electrode for a surgical instrument, in particular an instrument for connecting and cutting, as well as to a cutting electrode produced by the method, and to a surgical instrument which has a corresponding cutting electrode.

US Pat. No. 8,740,901 B2 discloses a surgical instrument for connecting and cutting vessels, that is, for connecting and cutting tissue, in which both the sealing of the tissue and the cutting of the tissue are performed electrically. To connect the vessels, sealing electrodes placed on the clamps of two jaws are used, which conduct current through the tissue captured between the clamps, which thereby heats up and coagulates. In this way, vessels captured by the instrument can be sealed. In this case, a cutting electrode placed on one of the jaws serves to cut blood vessels. In this case, depending on the embodiment, the cutting electrode can be built into the insulating material at different depths in such a way that only its edge and parts of its flat sides protrude openly from the cutting electrode.

From EP 0852480 B1 there is known a scalpel-shaped electrosurgical instrument in which the flat, blade-shaped electrode is provided with a thick insulating coating on both its flat sides. This coating also covers the ribs, but there it is relatively thin. Accordingly, the high-frequency current emanating from the tool should preferentially flow through the edges of the tool.

Such a tool is also known from EP 3132765 A1. It has on its upper branch, equipped with a cutting electrode, an insulator, which in the center has a thin wall section directed as an emphasis for the opposite branch. A cutting electrode is inserted into the edge of this wall section.

The design of the insulator with a cutting electrode can, in principle, also be taken from US 2016/0249975 A1. The cutting electrode is made by means of narrow strip-shaped metal sections that have different ohmic resistances.

Another prior art is shown by US 8394094 B2. This publication proposes holding the cutting electrode between two insulating elements that substantially cover the flat sides of the cutting electrode and leave the edge of the cutting electrode exposed.

The trend in the development of surgical instruments is aimed at creating thin, but at the same time very effective and reliably functioning instruments. Such tools must produce the most accurate cut in the shortest time. This should be done with as little current as possible to allow simultaneous tissue coagulation. First of all, in cases where the coagulating electrodes and the cutting electrode are simultaneously powered by the same power-limited generator, energy savings during cutting can be significant.

It was found that the cutting process depends significantly on the geometry of the cutting electrode and its insulation. However, the production of corresponding cutting electrodes is difficult.

Based on the above, the purpose of the invention is to provide a method for manufacturing a cutting electrode.

This goal is achieved by the method according to claim 1 of the claims.

The method proposed in the invention for manufacturing a cutting electrode for a surgical instrument intended for connecting and cutting tissue, using a workpiece made of electrically conductive material, includes: making a programmed destruction site on the workpiece, dividing the workpiece into first and second sections; placing a workpiece equipped with a place of programmed destruction in a casting mold, which has a seat that tightly encloses the first section and forms a cavity around the second section; filling the mold with polymer to create a plastic body that encloses the second portion; opening the mold and removing the plastic body with the workpiece captured in it; and breaking off the first portion from the second portion along the site of the programmed failure.

Thus, the method according to the invention is based on providing a flat piece of electrically conductive material, preferably a sheet metal piece, which has both a portion that subsequently forms an electrode and a portion that serves only for manipulation. This workpiece is equipped with a programmed destruction site, which divides it into first and second sections. The first section serves only for manipulation, while the second section subsequently forms the electrode. The workpiece is, for example, a thin metal sheet, the thickness of which, depending on the application, ranges from a tenth of a millimeter to several tenths of a millimeter. In a preferred embodiment, the thickness is 0.1 mm. The metal can be represented by steel, and the steel is preferably not ductile and, above all, not plastically deformable.

The location of the programmed destruction is preferably made by means of a linear zone in which the thickness of the sheet metal blank is reduced. The thickness reduction can be accomplished by means of a straight or arcuate groove that extends along the flat side of the workpiece, preferably from one edge to the other. Alternatively, two grooves or two grooves may also be provided which are located on both opposite flat sides of the workpiece and have the same locations and the same shapes. In other words, they are oriented parallel to each other and define a surface that is perpendicular to the flat sides of the workpiece.

The location of the programmed destruction can be accomplished by grinding, milling, etching, stamping, roller rolling or a similar method suitable for locally reducing the thickness of the workpiece. In addition, it is also possible to create a programmed fracture site through a series of perforations or slits, or through a local change in the material, for example local embrittlement of the material. It can be caused thermally, for example by local laser hardening.

In the next step, the workpiece, equipped with a place for programmed destruction, is inserted into the nest of the casting mold, which tightly grips the first section in such a way that the second section protrudes into the void or into the cavity of the casting mold. In this case, the casting mold is preferably designed in such a way that the location of the programmed destruction is positioned exactly at the edge of the cavity. In the next step, the mold is filled with polymer in such a way that it flows around the second section and, if necessary, also penetrates the perforations provided in the second section. Thus, a geometric closure is obtained between the plastic housing and the second section. The preferred casting method is injection molding.

After opening the mold and removing the plastic body with the workpiece captured therein, the first section of the workpiece is broken off from the second section at the site of the programmed destruction, for example, by hand or by means of tongs or other suitable working device. This creates a fracture edge along the edge of the plastic body, along which a second section of the workpiece now extends openly as a finished cutting edge.

Thus, the cutting edge is naturally sharp and does not require further processing. Damage or stress on the plastic housing resulting from post-processing steps is minimized. The metal sheet of the cutting electrode is preferably housed in a plastic housing in a symmetrical manner.

The method makes it possible to create an electrically conductive, substantially linear, preferably metal, cutting edge directly on an integral or composite plastic body, without the need to open parts of the flat side of the cutting electrode. To separate the first section there is no need to reserve surface areas for grippers, tongs or the like. The cutting edge may be flush with the plastic housing, protruding slightly from it, or positioned slightly below adjacent surfaces of the plastic housing. Thus, the manufacturing process is simple and reliable in use with high quality, and also ensures the highest cutting performance due to the current limitation at the narrow breaking edge of the cutting electrode. In this case, the cutting electrode can consist of metal or electrically conductive ceramics. The method according to the invention makes it possible to produce a cutting electrode with particular precision, in which the electrode is centrally integrated into a plastic housing in such a way that the plastic walls on both sides of the electrode have the same thickness.

When the size of the first section is larger than or equal to the size of the second section, manipulation during production and subsequent separation of the first section from the rest of the second section molded into the plastic body can very easily be done also by hand.

When the first section is positioned in the mold by means of at least one pin, preferably at least two pins, particularly reliable positioning of the workpiece in the mold can be obtained.

The location of the programmed destruction is preferably designed as a thin strip-like, i.e. linear, area with reduced material thickness. It can be done by single- or double-sided grinding, roller rolling or etching of the workpiece or otherwise. The area of reduced material thickness can be represented by a groove. This groove may have a circular, rectangular, trapezoidal, triangular or arcuate cross-section. This groove, regardless of its shape, preferably has a depth that is at least one third, more preferably at least one half, of the thickness of the workpiece. Both groove depth and workpiece thickness should be measured perpendicular to the flat side of the workpiece. If the grooves are placed in the workpiece on both sides, their depth is preferably from 1/6 to 1/4 of the thickness of the workpiece.

The invention also relates to a cutting electrode for a surgical instrument intended for connecting and cutting tissue, manufactured in the manner described above. The cutting electrode proposed in the invention has a plastic housing, into which is built an electrode made of electrically conductive material having an open breaking edge.

Preferably, the plastic body consists of a flexible polymer, especially an elastic polymer such as, for example, silicone, or a silicone-like polymer, elastomer or the like.

The electrode preferably has a constant thickness, and near the fault edge the thickness is reduced so that the narrowing region is adjacent to the fault edge. This narrowing area helps concentrate the current on the cutting edge in such a way that a fast and clean cut is achieved.

The plastic body preferably at least extends into the constriction region, and more preferably extends into, or may be configured to overlap, the constriction region such that the exposed fracture area of the electrode is preferably no greater than the cross-sectional area of the cutting electrode. This means that the sides of the electrode are preferably coated up to the breaking edge of the polymer.

On both sides of the breaking edge, the plastic housing has end surfaces, the width of which is preferably less than twice the thickness (width) of the electrode. This prevents pinching and mechanical cutting of tissue, and also ensures that the required cut is made entirely or predominantly electrically rather than mechanically.

Other details of advantageous embodiments of the invention may be obtained from the drawing, description of the invention or claims. Shown on:

Fig. 1 is a surgical instrument in an exemplary embodiment and in a perspective simplified representation,

Fig. 2 removed from the tool according to FIG. 1 working element in a simplified image in vertical section,

Fig. 3 - cutting electrode of the working body according to Fig. 2 in a simplified perspective view,

Fig. 4 blank for making a cutting electrode in a side view,

Fig. 5 a casting mold with a blank in an exploded view, in a section perpendicular to the parting plane of the casting mold,

Fig. 6 - workpiece in a fragmentary cross-sectional image, in the area of its place of programmed destruction,

Fig. 7 - an alternative embodiment of the workpiece in a fragmentary cross-sectional image, in the area of its place of programmed destruction,

Fig. 8 a blank equipped with a plastic housing for the manufacture of a cutting electrode,

Fig. 9 a cutting electrode in a vertically cut fragmentary view, in the first embodiment, and

Fig. 10 - cutting electrode as shown in FIG. 9, however, in a modified embodiment.

Fig. 1 illustrates a surgical instrument 11 which is provided primarily for laparoscopic treatment of a patient. The tool 11 has a body 12 with a handle 13 and a drive lever 14 provided on it. A rod 15 extends away from the body 12, at the distal end of which the working body 17 is held 16. It has a first jaw 18 and a second jaw 19, of which at least one , by actuating the lever 14, is able to move towards and away from the other, allowing the tissue to be caught between them.

The jaws 18, 19 form a forceps-like working body 17, which is provided for sealing the tissue and/or for separating the tissue. For this purpose, both jaws 18, 19, as is known in principle from EP 3 132 765 A1, for example, can be connected to different poles of the voltage source and thus define a coagulation gap 20, 21 between their arms. Placed between them is a preferably elastic stop 22, and on the opposite jaw 19 a cutting electrode 23. This electrode has a base or fastening section 24 and a wall section 25, both of which consist of a polymer, preferably an elastic polymer, with the wall section 25 and, if necessary, at least in sections also built into the base section 24 is an inwardly protruding electrode 26, preferably consisting of metal. Only its narrow edge 28 extends openly at the end 27. Otherwise, the electrode 26 is built into the wall section 25 and the base section 24 such that it is electrically isolated.

The end-effector 17 may also be part of another instrument, for example an instrument used endoscopically or formed for open surgical use.

The cutting electrode 24 is manufactured as follows.

Manufacturing starts from a blank 29, as illustrated in FIG. 4. This workpiece 29 consists of a suitable electrode material, such as a steel alloy, a titanium alloy, or an electrically conductive ceramic. Preferably, the workpiece 29 consists of a spring material that does not, however, have a significant ability to be plastically deformed. First of all, most preferably, the material reaches its fracture limit without previous plastic deformation.

The workpiece 29 is preferably provided with a line-shaped programmed destruction site 30 that separates the first region 31 of the workpiece 29 from the second region 32. The second region 32 subsequently forms the electrode 26, while the first region 31 serves only for temporary manipulation. The programmed fracture site 30 is a linear weakening of the material of the workpiece 29, for example through a groove 33 formed in the workpiece 29, as shown in FIG. 7. Instead of having a groove 33 on only one flat side of the workpiece 29, a programmed break point 30 can also be provided, as shown in FIG. 6, by means of two grooves 33, 34, which run parallel to each other on the flat sides of the workpiece 29 facing away from each other. Both grooves 33, 34 extend along the same routes and are placed in the same positions.

Regardless of whether only one groove 33 or two grooves 33, 34 are provided, they can be formed in any suitable manner, for example by grinding, milling, stamping, roll rolling or etching. In this case, depending on the chosen method and the required shape of the edges, the cross-section of the grooves 33, 34 can be made round, rectangular, triangular, quadrangular, trapezoidal or also, especially during etching, of an indefinite shape. However, the depth and width of the groove are also set during etching.

One or more positioning structures may be provided in the first portion 31, for example in the form of positioning holes 35, 36. These may serve, for example, to position the workpiece 29 in a mold 37 with two mold halves 38, 39, as shown in FIG. 5.

The mold halves 38, 39 are each equipped with a seat, which in the area of the first workpiece section 31 has such shape and depth dimensions that when the mold 37 is closed, the workpiece 29 is fixed relative to the first section 31, and both mold halves 38, 39 are superficially adjacent to the first section 31. First of all, , wherein the area of the mold halves 38, 39 holding the first section 31 is closed substantially flush with the location 30 of the programmed destruction. Thus, when the mold 37 is closed, a cavity 40 is formed around the second section 32, into which the second section 32 projects in a cantilevered manner. This cavity 40 is again closed flush with the programmed destruction site 30.

To produce the cutting electrode 22, section 32, with the mold 37 closed, is filled with a suitable polymer, for example silicone, which can also penetrate holes 41, which can be made in the second section 32 for fixing the polymer to the workpiece with a geometric lock. The shape of the holes can be round or rectangular.

After the polymer has cured and the mold 37 has been opened, the preform 29 with the plastic body 42 formed thereon can be removed from the mold 37. As illustrated in FIG. 8, the location 30 of the programmed destruction is now located directly at the upper end of the wall section 25. A cable 43 located on the section 32 of the workpiece 29, if necessary, protrudes from the plastic housing 42.

To complete the production of the cutting electrode 23, the first section 31 is now moved relative to the plastic housing 40 in the direction indicated in FIG. 8 by means of the arrow P direction with its reciprocating rotation, as a result of which the first section 31 is broken off at the site 30 of the programmed destruction from the second section. This creates a fault edge 44, as shown in FIG. 9. The narrowing area 45 is formed from the former groove 32 such that the fracture edge 44 has a smaller width than the thickness of the second section 32 built into the plastic housing. Both the width of the fracture edge 44 and the thickness of the second section 32 are located in FIG. 9 horizontally, that is, to be measured, in any case, perpendicular to the flat side of the second section 32.

The wall section 25 has, at its end 27 on both sides of the fault edge 44, smooth or rounded surface sections 46, 47, the width of which respectively exceeds, preferably, a maximum of 10 times, more preferably a maximum of three times, or also a maximum of two times the thickness of the second plot 32.

While the wall portion 25 may be directly adjacent to the end of the constriction region 45, as illustrated in FIG. 9, it can also extend, according to FIG. 10, inside the region of the constriction 45 in such a way that it is also partially or completely covered with polymer and exclusively the fracture edge 44 is exposed. Due to this, a particularly high current concentration is achieved.

The fracture edge 44 may be naturally sharpened and not post-processed. After breaking off the first section 31 from the second extruded section 32 according to FIG. 8, the cutting electrode 23 is ready-made and can be built into the tool according to FIG. 1. When cutting, on the fault edge, due to roughness, local current concentrations are formed, which ensure cutting. However, it is also possible to further treat the fracture edge, for example by polishing, in particular electropolishing.

Described in connection with FIGS. 5, as well as 8-10, are equally valid for the blanks 29 according to FIG. 6 and blanks 29 according to FIG. 7.

The method according to the invention serves for the production of a cutting electrode for a surgical instrument 11, wherein the method prevents the application of the force necessary for separating the cross-section of the cutting electrode 23 after placing the plastic housing on the cutting electrode 23. The production of the cutting electrode 23 starts from a workpiece 29, which is equipped with a programmed destruction point 30 . It is endowed with such dimensions that it is possible to separate it with only minor forces, which are, first of all, so small that they can also be transmitted through the plastic housing. The programmed destruction location 30 subdivides the workpiece 29 into a first area 31, which serves only to manipulate and position the workpiece 29 in the mold 37, and a second area 32, which opens into the cavity of the mold 40 and is extruded into a polymer.

Once formed, the first portion 31 can be easily broken off from the cutting electrode 23. The resulting fracture edge 44 forms an ideal cutting edge.

List of reference designations:

11 instrument

12 building

13 handle

14 lever

15 stock

16 distal end of rod 15

17 working body

18, 19 branches

20, 21 coagulation gap

22 emphasis

23 cutting electrode

24 base section

25 wall section

26 electrode

27 end

28 cutting edge

29 blank

30th place of programmed destruction

31 first plot

32 second section

33, 34 grooves

35, 36 positioning holes

37 casting mold

38, 39 half-forms

40 cavity

41 holes

42 plastic housing

43 cable

P arrow

44 fault edge

45 narrowing area

46, 47 surface areas

Claims (20)

1. A method for manufacturing a cutting electrode for a surgical instrument intended for connecting and cutting tissue, using a blank made of electrically conductive material, characterized in that it includes: - execution of a place of programmed destruction on the workpiece, dividing the workpiece into the first and second sections, - placing a workpiece equipped with a place of programmed destruction in a casting mold, which has a seat that tightly encloses the first section and forms a cavity around the second section, - filling the mold with polymer to create a plastic body that covers the second section, - opening the mold and removing the plastic body with the workpiece captured in it, and - breaking off the first section from the second section along the site of programmed destruction. 2. The method according to claim 1, characterized in that the size of the first section is greater than or equal to the size of the second section. 3. Method according to one of the preceding claims, characterized in that the first section is positioned in the mold by means of a positioning structure. 4. Method according to one of the preceding claims, characterized in that the workpiece is provided with an electrical connecting conductor before being placed in the mold. 5. The method according to one of the previous paragraphs, characterized in that the location of the programmed destruction is made in the form of a linear area with a reduced thickness of the material. 6. The method according to claim 5, characterized in that the area of reduced material thickness is formed by at least one groove located on at least one flat side of the workpiece. 7. The method according to claim 6, characterized in that the groove is made by etching. 8. Cutting electrode for a surgical instrument intended for connecting and cutting tissue, manufactured by the method according to one of paragraphs. 1-7, characterized in that it has a plastic body into which is built an electrode made of electrically conductive material having an open fracture edge. 9. The cutting electrode according to claim 8, characterized in that the plastic body is made of a flexible polymer, in particular an elastic polymer, especially silicone. 10. Cutting electrode according to claim 8 or 9, characterized in that the electrode has a constant thickness, and near the fault edge the thickness is reduced so that the narrowing area is adjacent to the fault edge. 11. Cutting electrode according to claim 10, characterized in that the plastic body reaches the narrowing area. 12. The cutting electrode according to claim 10, characterized in that the plastic body is made to cover the narrowing area. 13. Cutting electrode according to one of paragraphs. 8-12, characterized in that the electrode has holes pierced by polymer. 14. Cutting electrode according to one of paragraphs. 8-13, characterized in that the width of the fracture edge is less than the thickness of the electrode, preferably does not exceed half the thickness of the electrode. 15. A surgical instrument for connecting and cutting tissue, containing a cutting electrode according to one of paragraphs. 8-14.