Electrosurgical instrument

Abstract

The invention relates to an electrosurgical instrument (10) for the thermal cutting of biological tissue, in particular of a patient. The instrument (10) comprises two jaws (15, 16), wherein at least one of the jaws (15) is configured to be moved towards and away from the other jaw (16). At least one of the jaws (15) comprises a thermal cutting element (22) having an electrically conductive cutting conductor (36) and an electrically conductive return conductor (37) which are electrically connected to each other. The cutting element (22) is arranged such that the cutting conductor (36) is thermally exposed at least on the side of the one jaw (15) facing the other jaw (16), and such that the return conductor (37) is surrounded by an insulation (34). The return conductor (37) comprises a lower electrical resistance than the cutting conductor (36) in the direction of the current flow, and preferably a higher thermal conductivity than the cutting conductor. In doing so, during the supply of electrical current to the cutting element (22), less heat and temperature are generated at the return conductor (37) than in the cutting conductor (36), and the return conductor (37) can be used for thermal dissipation.

Description

Technical Field

[0001] This invention relates to an electrosurgical instrument, particularly for the thermal cutting of biological tissues in human or animal patients, and for achieving additional tissue effects where appropriate. Background Technology

[0002] Electrosurgical instruments with thermal cutting elements in different embodiments are known from the prior art.

[0003] WO2023 / 187737A1 discloses a surgical instrument with a thermal cutting device. The thermal cutting device includes a longitudinal support having a proximal end and a distal end, and a cutting blade arranged along its upper surface. Furthermore, the cutting device includes a dielectric insulator arranged along at least one side of a substrate and extending at least partially along the substrate from the proximal end to the distal end. Additionally, the cutting device includes at least one resistive element adapted for connection to an energy source and arranged for thermal connection to the substrate. The at least one resistive element is thus arranged such that it extends along the dielectric insulator to its distal end segment. Furthermore, the cutting device includes an encapsulating material arranged on the dielectric insulator and on the at least one resistive element. The distal end of the substrate includes a mechanical interface configured to engage with a segment of a gripper for attaching the substrate to the gripper.

[0004] Other thermal cutting elements are described in WO2023 / 187735A1, US2023 / 0363812A1, WO2023 / 187736A1, US2023 / 0310063A1, EP3861950A1, EP3769709B1, US2022 / 0378494A1 and US2023 / 0285064A1.

[0005] US2023 / 240740A1 describes a thermal cutting element in which a heating element is applied to an electrically insulating support. The heating element may have a cross-sectional area that varies along its length. Additionally, the heating element includes different sections, which may be constructed, for example, in a straight or meandering manner, to produce a desired temperature profile.

[0006] EP4076239B1 describes a method for producing a thermal cutting element for surgical instruments. In this method, a coating is applied, at least on a section of a support member, by means of a plasma electrolytic oxidation method. A heating element is then applied to this coating.

[0007] All heating elements found in the prior art include a support material with relatively high thermal conductivity, allowing the entire gripper to heat up in undesirable locations, such as the outside of the gripper. This can make surgery more difficult for surgeons because the instrument gripper (especially during prolonged surgeries) can thermally adhere to the patient's tissue in undesirable locations in the operating room, and can unintentionally damage the tissue there, which can lead to a prolonged recovery period for the patient after surgery. Summary of the Invention

[0008] From this point forward, the object of the present invention is to provide an improved electrosurgical instrument for thermal cutting of biological tissues. Ideally, the grippers of the instrument should preferably remain completely cool or only heat up to a minimal degree during use.

[0009] This objective is achieved by means of the electrosurgical device according to claim 1: The surgical instrument according to the invention is specifically configured for thermal cutting of a patient's biological tissue. The instrument includes at least two jaws, wherein at least one of the jaws is configured to move relative to the other jaw toward or away from it. For example, one of the jaws is configured to rotate about a pivot axis by means of a pivoting device. Additionally, the two jaws can be movably configured toward and away from each other in a clamp-like manner. At least one of the jaws includes a thermal cutting element having a conductive cutting conductor and a conductive return conductor. The cutting element is arranged such that the cutting conductor is thermally exposed at least on the jaw's side facing the other jaw, and the return conductor is (completely) surrounded by an insulator. The cutting conductor can be constructed in a bare metal manner or covered with a thermally conductive, electrically insulating coating. For example, the coating can have hydrophobic properties, thereby preventing the cutting conductor from adhering to the patient's biological tissue.

[0010] The cut conductor and return conductor can be connected to and supplied with current from a current source. Such a current source can be a DC source or an AC source, such as a high-frequency source (HF source).

[0011] The special feature of this invention is that the return conductor has a lower resistance than the cutting conductor, and preferably a higher thermal conductivity. The insulator is constructed in a manner that is both electrically and thermally insulating, such that during current supply to the cutting element, heat is primarily generated in the cutting conductor and is particularly impeded by the insulator from dissipating backward. For example, the insulator may be made of silicone resin. During current supply to the cutting element, much less heat can be generated in the return conductor than in the cutting conductor because the return conductor has a lower resistance. In particular, the return conductor includes a core (return conductor core) covered by a coating. Due to the coating, the characteristics of the return conductor can be affected, particularly the resistance and thermal conductivity of the return conductor. Preferably, due to the coating, the resistance of the return conductor can be configured to be lower than the resistance of the return conductor core. Preferably, the return conductor core is made of the same material as the cutting conductor.

[0012] The cutting conductor and the return conductor are electrically and physically connected to each other. Particularly in the conductor direction (meaning in the direction in which the current flows during use of the cutting element and opposite thereto), the return conductor has a higher thermal conductivity than the cutting conductor. The coating of the return conductor particularly has a higher thermal conductivity than the base material of the return conductor core. The coating provides that the resistance of the return conductor (meaning the entire composition of the return conductor core and coating) is lower than that of the cutting conductor. Furthermore, due to the coating, the return conductor has a higher thermal conductivity than a return conductor core without a coating. Because of the high thermal conductivity of the return conductor, heat generated at the return conductor can be dissipated, which is particularly advantageous if the return conductor has a particularly small cross-section. In doing so, overheating of the return conductor (the overall composition of the return conductor core and coating) is avoided. In this way, the jaws can be constructed to be particularly thin and particularly flat, so as not to transfer too much heat locally from the return conductor to the support portion of the jaws and therefore to the outside of the jaws during cutting.

[0013] The cutting conductor and the return conductor are preferably a single unit. For example, the latter is at least substantially constructed in a U-shape, wherein the cutting conductor and the return conductor may form a leg of the U-shaped cutting element in each case.

[0014] The gripper specifically includes a rectangular support portion extending from a proximal region to a distal end region, in which a hinged device for a pivotable support of another gripper can be arranged. The support portion restricts a holding space in which the cutting element is preferably arranged vertically. Thus, the cutting conductor is positioned above the return conductor.

[0015] The cutting conductor and the return conductor are preferably made of the same base material. Regarding the latter, different coatings can be applied at different locations; individual locations (e.g., cutting conductors, connection sections, etc.) may also be uncoated.

[0016] The U-shaped cutting element preferably opens towards the proximal region of the gripper. At the proximal end, a connecting section or connecting element can be electrically connected to the cutting conductor and the return conductor, by means of which the cutting element can be connected to the supply line. Through the latter, the cutting element can be connected to and supplied with current from a current source. Due to the single construction of the cutting element, especially in the distal end region of the gripper (where the cutting conductor is physically connected (meaning both electrically and thermally) to the return conductor), it is necessary to avoid any connecting seams (e.g., welds or brazes). The risk of conductor breakage between the cutting conductor and the return conductor is significantly reduced during use of the instrument, and the associated mechanical stress on the cutting element is significantly reduced.

[0017] The return conductor core is preferably at least partially provided with a coating extending in the longitudinal direction. This coating preferably covers the entire outer periphery of the return conductor core. The coating allows the return conductor core and the cut conductor to be manufactured from a single material and in a single manner, thereby eliminating the need for additional components to connect the two conductors (the cut conductor and the return conductor). Preferably, the entire return conductor is provided with the coating, whereby heat generated at the return conductor can be extensively dissipated from the return conductor by means of the coating.

[0018] The coating is preferably made of a material having a lower resistivity than the base material of the cutting conductor. Additionally, the coating material preferably has a higher specific thermal conductivity than the base material of the cutting conductor. The cutting conductor and return conductor can be made of the same material as stainless steel, a nickel-based alloy (which may include iron, molybdenum, niobium, cobalt, manganese, copper, aluminum, titanium, silicon, carbon, sulfur, phosphorus, and boron), or an iron-chromium-aluminum alloy. The coating is, for example, made of copper, silver, and / or aluminum. The specific thermal conductivity of the coating is particularly high, exceeding 200 W / (m∙K).

[0019] Specifically, the cutting conductor has a larger cross-sectional area and a higher specific resistance than the return conductor, resulting in a higher resistance, preferably considerably higher, than that of the return conductor which has a coating with lower resistance and higher thermal conductivity. Consequently, the heat generated in the cutting element can be primarily generated at the cutting conductor, while the return conductor remains relatively cool and serves for heat dissipation.

[0020] In the edge regions of the grippers, they preferably each include at least one sealing electrode arranged at a distance from the cutting conductor. In particular, at least on their lateral sides, the cutting conductor is surrounded by the sealing electrode between the distal and proximal ends of the grippers.

[0021] The sealing electrode is specifically configured to be connected to a current source, such as an HF current source. The sealing electrode and the cutting element can be supplied by means of a (single) HF current source.

[0022] The sealing electrode and the cutting conductor can be supplied from a common power source (e.g., an HF current source). A network (e.g., a transformer) within the apparatus can thus be used to supply the different voltages required for the operation of the sealing electrode and the cutting element from the voltage of the power source. The network (transformer) can be part of the apparatus or part of the power generator. However, it is also possible to supply the sealing electrode and the cutting element with their own (separate) HF current sources.

[0023] Specifically, the other (second) jaw also includes at least one sealing electrode in the edge region. The sealing electrode is preferably constructed identically to the sealing electrode of one (first) jaw, such that they are arranged on top of each other, but with a distance between them when the jaws are closed. The two sealing electrodes are connected to the terminals supplying the generator. An elastic counterweight is arranged in the second jaw, against which the cutting conductor travels during jaw closure, causing slight elastic deformation of the counterweight.

[0024] Preferably, the insulator (and also the counterweight) is made of a material with a lower thermal conductivity than the cut conductor, thereby making the cut conductor largely thermally insulated from the return conductor. Therefore, the heat generated by the cut conductor can be concentrated in a narrow strip of biomaterial and become effective there.

[0025] At least one attachment protrusion may be constructed on the cutting conductor, the attachment protrusion being surrounded by an insulator. Preferably, the attachment protrusion includes at least one undercut section. The attachment protrusion is particularly completely surrounded by an insulator, thereby preventing: mechanical separation of the cutting conductor from the insulator, or the possibility of it being pulled out of the insulator, for example if the cutting conductor adheres to biological tissue and the instrument moves further.

[0026] At least one spacer element may be arranged between the cut conductor and the return conductor. The spacer element may be made of, for example, an electrically and thermally insulating material, such as ceramics, such as ZrO2 or AlO2. In particular, the material constituting the spacer element may withstand temperatures exceeding 350°C.

[0027] In embodiments, for example, the spacer element may have an upper (planar) side and a lower (planar) side. Preferably, the spacer element abuts against the cut conductor with its upper side and / or against the return conductor with its lower side. This prevents the cut conductor from bending under mechanical stress. The insulator includes a certain degree of elastic deformability, especially if it is made of silicone. Due to the spacer element, the cut conductor can be supported on the return conductor, thereby preventing deformation of the cut conductor.

[0028] In another embodiment, a plurality of spacer elements, particularly at least three spacer elements, are arranged between the cutting conductor and the return conductor. Each of the spacer elements may include, for example, a return conductor cavity on its underside, within which the return conductor is placed such that the return conductor is at least partially surrounded and held by the spacer element, thereby facilitating the positioning and securing of the cutting element, composed of the cutting conductor and the return conductor, in a gripper. Preferably, the return conductor cavity opens at a lateral side. This simplifies the assembly of the cutting element on the gripper. Preferably, the plurality of spacer elements, particularly at least three spacer elements, are arranged in such a manner that the sides facing the opening of the return conductor cavity alternate.

[0029] Preferably, the plurality of spacer elements have a support surface on which the cut conductor is supported. Specifically, the lower side of the cut conductor is supported on the support surface. Each spacer element includes at least one lateral stop protruding from the support surface, and the cut conductor laterally abuts against the at least one lateral stop. Preferably, the plurality of spacer elements are arranged such that the lateral portions of the at least one stop protruding from the support surface alternate.

[0030] Preferably, if the other (second) gripper includes a counterweight arranged on a side facing one (first) gripper, and therein defining a (planar) counterweight surface for cutting the conductor of one (first) gripper. The counterweight is preferably constructed in a manner that provides electrical and thermal insulation. The counterweight preferably incorporates a degree of elasticity such that if a portion of the cutting element penetrates within the counterweight, the counterweight can deform slightly. Due to this elasticity, the counterweight provides that the material abuts against the cutting conductor during cutting. Specifically, the cutting conductor protrudes from a surface formed of an insulator in the direction toward the other gripper. Preferably, the cutting conductor may protrude by about 0.10 mm, 0.15 mm, or more.

[0031] In particular, the counterweight can be configured such that when the grippers are closed, the cutting conductor can penetrate through the counterweight along the entire cutting conductor, preferably to a uniform depth. Attached Figure Description

[0032] Further details of advantageous embodiments of the invention are available from the dependent claims, the drawings, or the description. The drawings show: Figure 1 Examples of electrosurgical instruments according to the present invention are shown in perspective view; Figure 2 Examples of tools for instruments, showing the distal end of the instrument with detailed illustrations; Figure 3 An example of the instrument's first gripper is shown in top view; Figure 4 An example of the instrument's second gripper is shown in top view; Figure 5 Examples of cut components and insulator portions are shown in detailed illustrations; Figure 6 An example of two grippers of an instrument in a closed state is shown in a longitudinal sectional view; Figure 7 An example of two grippers of an instrument in a closed state is shown in cross-sectional view; Figure 8 Another example of two grippers of an instrument in a closed state is shown in cross-sectional view; Figure 9 Another example of the instrument's first gripper is shown in a longitudinal sectional view; Figure 10 Showing a detailed illustration of the cut element with spacers, viewed from one side; Figure 11 A detailed illustration of the cut element with spacers, viewed from the other side; and Figure 12 The lower gripper of the instrument is shown in a cross-sectional view. Detailed Implementation

[0033] Figure 1 An example of an electrosurgical instrument 10 configured for thermal cutting of a patient's biological tissue is shown. The instrument 10 includes a longitudinal handle 11 extending from a proximal end 12 to a distal end 13. A tool 14 is disposed at the distal end 13 of the electrosurgical instrument 10, and the tool 14 includes a first jaw 15 and a second jaw 16, whereby at least one of the two jaws 15, 16 is movable relative to the other.

[0034] A handle 17 is disposed on the proximal end 12 of the electrosurgical instrument 10 for manipulating the tool 14. A channel may be provided in the handle 11, in which a power supply line 18 may be arranged to extend from the proximal end 12 to the distal end 13 of the instrument 10 for electrically supplying the tool 14 having a cutting electrode and a sealing electrode disposed therein. Additionally, one or more control lines may be disposed in the handle 11, at least one of which is connected to at least one of two grippers 15, 16 for opening and closing the latter. An instrument supply line 19 is attached to the handle 17 of the instrument 10, by means of which the electrosurgical instrument 10 can be connected to a supply device for supplying voltage, current, or other media to the instrument 10.

[0035] Figure 2A detailed illustration shows the tool 14 arranged on the distal end 13 of the handle 11. The two jaws 15, 16 can be opened and closed in a pliers-like manner. For this purpose, at least one of the two jaws 15, 16 (in this embodiment, the second jaw 16) can be pivoted relative to the stationary first jaw 15 by means of a hinge mechanism indicated by its pivot axis 21. Alternatively, the two jaws 15, 16 can also be pivotally arranged toward and away from each other. The hinge mechanism can be implemented by means of one or two pivot bearings, slotted guides, spring hinges, etc.

[0036] A thermal cutting element 22 is arranged in at least one of two grippers 15, 16 for thermal cutting of biological tissue. Figure 2 In the middle, the jaws 15 and 16 are constructed in a particularly narrow and thin manner, and are configured to be at least substantially straight. (And...) Figure 2 Unlike the illustrations, the grippers 15 and 16 may also have slight curvature, thereby allowing the electrosurgical instrument to prepare, for example, organs or other biological tissues. The electrosurgical instrument 10 is specifically used for cutting, separating, closing, and sealing blood vessels, such as blood vessels.

[0037] The first gripper 15 is formed of a rigid support portion 23, for example, made of metal, which may have an electrically insulating material at its outer side 24. Alternatively, the support portion 23 may also be partially or entirely made of a mechanically stable, less flexible or non-flexible, and electrically insulating plastic. Furthermore, the support portion 23 may be a composite portion and made of, for example, a metal insert overlaid with molded plastic.

[0038] Along its two edge regions 25, the support portion 23 of the first gripper 15 is provided with sealing electrodes 26 and 27, which can be connected to the generator by means of wires not shown. Figure 2 As depicted, the two sealing electrodes 26 and 27 are physically and electrically connected to each other in the distal end section 28 of the first gripper 15. Alternatively, separate sealing electrodes 26 and 27 may be provided, which are at equal or different potentials and are not physically connected in the distal end section 28.

[0039] The second gripper 16 also includes a support portion 29, which may again be made of metal or also of plastic or a metal-plastic composite. At its outer edge, the support portion 29 supports sealing electrodes 30, 31, extending from the region 32 near the connector to the distal end section 28. The profile of the support portion 29 of the second gripper 16 conforms to the profile of the first gripper 15. When the two grippers are closed, sealing electrode 26 aligns with sealing electrode 30. Additionally, sealing electrode 27 aligns with sealing electrode 31. Furthermore, sealing electrodes 30, 31 may be electrically and physically connected to each other in the distal end section 28 of the second gripper 16.

[0040] Figure 3 A top view showing the first gripper 15. The support portion 23 of the first gripper 15 includes a groove 33 in which the cutting element 22 is located. The cutting element 22 is surrounded by an insulator 34 such that the top side of the cutting element 22 (in which the cutting conductor 36 is disposed) protrudes from the insulator 34.

[0041] Figure 4 A top view of the second gripper 16 is shown. In this embodiment, no cutting element 22 is arranged in the second gripper 16. Alternatively, the cutting element 22 may also be arranged in the second gripper 16, as in the first gripper 15. Figure 4 In the example shown, the support portion 29 of the second gripper 16 includes a groove 35 in which the counter-pressure body 50 is arranged.

[0042] Figure 5 The cutting element 22 is depicted in a longitudinal sectional view. The cutting element 22 includes a cutting conductor 36 and a return conductor 37. The cutting conductor 36 extends from a region 32 near the connector to a distal end segment 28. In the region 32 near the connector, the cutting conductor 36 and the return conductor 37 can be electrically contacted, for example, by form-fit and / or friction-fit. For example, the cutting conductor 36 and the return conductor 37 can be contacted by means of silver wire without requiring additional connecting elements. Figure 5 In the example shown, connecting element 38 is attached to cut conductor 36. Connecting element 38 may be a connecting sleeve, such as a crimp sleeve or the like. Return conductor 37 extends from the distal end section 28 to region 32 near the joint.

[0043] The return conductor 37 is positioned below the cutting element 36. In the distal end section 28, the cutting conductor 36 and the return conductor 37 are electrically and physically connected. Figure 5 In the example shown, in region 32 near the connector, the return conductor 37 also includes a connecting element 38. The cut conductor 36 and the return conductor 37 can be connected to a current source via the connecting element 38.

[0044] The current source can be the same current source also used for the sealing electrode, wherein an adapter network can be arranged between the current source and the cutting element. The adapter network can be configured to distribute the electrical power supplied by the current source across the sealing electrode and the cutting element, and to modify the supplied voltage to the required voltage. This also applies to the supplied current and the required current. However, the cutting element 22 can also be connected to a separate current source.

[0045] A spacer element 39 is disposed between the cut conductor 36 and the return conductor 37, wherein the spacer element 39 is made of thermally and electrically insulating material. The spacer element 39 is configured to be at least substantially planar, with its top side abutting against the underside of the cut conductor 36 and its underside abutting against the top side of the return conductor 37. The spacer element 39 serves to prevent the cut conductor 36 from bending under mechanical stress, instead supporting it on the return conductor 37 via the spacer element 39. The spacer element 39 is disposed between two positioning protrusions 40 that project onto the underside of the cut conductor 36 in a direction toward the return conductor 37, but do not contact the latter. Figure 5 On the side of the cut conductor 36 facing the return conductor 37, two additional attachment protrusions 41 are arranged, protruding from the cut conductor 36 in the direction toward the return conductor 37. The attachment protrusions 41 include undercut sections 42.

[0046] The return conductor 37 includes a core 52 wrapped with a coating 43, such that the return conductor 37 has a lower resistance than the cut conductor 36. Additionally, the return conductor 37 has a higher thermal conductivity in the direction of current flow than the cut conductor 36.

[0047] The coating 43 preferably completely covers the core 52 of the return conductor 37 circumferentially. Figure 5 In the example shown, coating 43 extends from the distal end section 28 to the region 32 near the joint. (Compared to...) Figure 5 Unlike the illustration, coating 43 may also exist only in the section of core 52 of return conductor 37 that preferably adjoins the distal end section 28 (where cut conductor 36 is electrically and physically connected to return conductor 37). Return conductor 37 and portions of cut conductor 36 are preferably embedded in insulator 34 such that only the upper portion of cut conductor 36 protrudes from insulator 34.

[0048] exist Figure 6 In the image, the tool 14 is shown in longitudinal section when viewed from the side. The cutting element 22 is embedded in the insulator 34 such that the return conductor 37 is completely surrounded by the insulator 34. The insulator 34 includes a plurality of insulator feet 51 on its underside, each including an undercut section 44. The insulator feet 51 are arranged in positions where openings 46 are provided in the support portion 23 of the first gripper 15.

[0049] For assembly of the cutting element 22, an insulator 34 is overmolded thereon. The insulator foot 51 additionally includes a tapered section 45, which allows the insulator 34 to be pulled through an opening 46 in the support portion 23 of the first gripper 15 at the insulator foot 51 until the undercut section 44 is seated within the opening 46. Due to the undercut section 44, the insulator 34, including the cutting element 22, is seated in a form-fitting manner within the support portion 23 of the first gripper 15. After the insulator 34 is inserted into the support portion 23, the insulator foot 51 can be cut off.

[0050] Figure 7 The cross-section of tool 14 passing through instrument 10 is shown. So far, the above explanation applies with respect to the reference numerals already introduced. Tool 14 shows closed grippers 15, 16. In the closed state of grippers 15, 16, the cutting conductor 36 at least partially overlaps with the counterweight 50. The counterweight 50 serves to ensure that the patient's tissue to be cut is in contact with the cutting conductor 36 to allow for clean cutting.

[0051] Furthermore, the cross-sectional area A36 of the cut conductor 36 is larger than the cross-sectional area A37 of the return conductor 37. Figure 7 In the embodiment depicted, the cross-sectional area A37 of the return conductor 37 is approximately half the cross-sectional area A36 of the cut conductor 36. Figure 7 In the example shown, the return conductor 37 is additionally coated with a coating 43 along its entire circumference. The smaller cross-sectional area A37 of the return conductor 37 initially results in a higher resistance for the return conductor 37 without the coating compared to the cut conductor. However, because the coating 43 is made of a particularly low-ohmic material, the resistance of the return conductor 37 is less than that of the cut conductor 37 despite the smaller cross-sectional area A37. For example, the width of the core 52 of the return conductor has an amount between 0.2 mm and 0.5 mm, and the height has an amount between 0.2 mm and 0.5 mm. The coating thickness of the coating 43 has an amount between 0.02 mm and 0.08 mm. The width of the cut conductor 36 also has an amount between 0.2 mm and 0.5 mm, while the height of the cut conductor 36 may have an amount between 0.4 mm and 1.00 mm. For example, the coating may be made of copper, aluminum, or silver. Copper includes approximately 0.01 Ω·mm. 2 The resistivity is approximately 0.016 Ω·mm², and the thermal conductivity is between 240 W / m·K and 380 W / m·K. However, silver and aluminum have a resistivity of approximately 0.016 Ω·mm². 2 / m and 0.026Ω·mm 2 The resistivity is approximately 0.7 Ω·mm², and the thermal conductivity is approximately 429 W / m·K and 160 W / m·K. The cut conductor 36 and / or return conductor 37 are preferably made of stainless steel, Inconel, or Kanthal-D, and have a specific resistance of approximately 0.7 Ω·mm². 2 / m and 1.5Ω·mm 2 The relatively high resistivity between 15 W / m·K and 25 W / m·K and the relatively low thermal conductivity between 15 W / m·K and 25 W / m·K.

[0052] Insulator 34 is both thermally and electrically insulating. This results in heat in the central region between the jaws 15, 16 being primarily maintained only on the cutting conductor 36. Conversely, heat transferred in the distal end section 28 of the first jaw 15 due to heat conduction to the return conductor 37 is specifically distributed by means of the coating 43 of the return conductor 37 and can be widely dissipated without creating localized hot spots. This allows the jaws 15, 16 to be constructed to be particularly fine, thin, and flat without heating the outer side of the jaws, especially during extended operation.

[0053] and Figure 7 Unlike the illustration, the support portion 23 of the first gripper 15 may include a recess 47 surrounding the opening 46 on its underside, allowing the insulator foot 51 to be cut off flush with the support portion 23. This is in Figure 8 As shown in the image.

[0054] exist Figures 9 to 12 Another example of a construction for a gripper is shown below. For Figures 9 to 12 For the examples depicted, the above explanation applies accordingly to the reference numerals in the accompanying drawings.

[0055] The difference between this example and the prior example is that the first gripper 15 includes only two insulator feet 51, but includes three spacer elements 39a, 39b, 39c. The conductor 36 is cut into different undercut sections 42a, 42b, 42c, which can be positioned within the insulator 34 (compare undercut section 42a) or within the spacer elements 39b, 39c (compare undercut sections 42b, 42c).

[0056] Spacer elements 39a, 39b, and 39c, together with undercut sections 42b and 42c, form a shape fit and fix the cutting conductor 36, thereby preventing the cutting conductor 36 from lifting due to tissue adhesion. Spacer elements 39a, 39b, and 39c prevent electrical contact between the cutting conductor 36 and the return conductor 37, as well as with the support portion 23 of the first gripper 15.

[0057] As in Figure 10 From one side and in Figure 11As shown from the other side, spacer elements 39a, 39b, and 39c additionally include lateral stops 53, which ensure the centered positioning of the cutting element 22 within the first gripper 15. The lateral stops 53 laterally adjoin a support surface 58 on which the cutting conductor 36 (particularly its underside) is positioned and supported. Spacer elements 39a, 39b, and 39c include return conductor cavities 54, each leading to a lateral side. Return conductor cavities 54 can be alternately inserted into the cutting conductor 36 and the return conductor 37, thereby achieving centered positioning within the support portion 23 of the first gripper 15. The proximal spacer element 39c further includes a base plate 55 adapted to the support portion 23, wherein the base plate 55 tapers toward the distal end 28 of the first gripper 15, such that the cutting conductor 36 can also be centered within the enlarged proximal region 32 near the connector.

[0058] Additionally, spacer elements 39a, 39b, and 39c include a transverse cavity 56 and a longitudinal cavity 57 through which the material of the insulator 34 can flow during production. The form fit between the spacer elements 39a, 39b, and 39c and the insulator 34 can be achieved in this manner.

[0059] Combinations of different shapes (and the shape fits between the undercut sections 44 of the insulator 51) prevent the cutting element 22 from lifting.

[0060] The spacer elements 39a, 39b, and 39c can be made of ceramics with electrical and thermal insulation properties, thereby avoiding the heat generated in the cutting element 22 and instead outputting it to the tissue mainly at the predetermined location (cutting conductor 36).

[0061] This invention relates to an electrosurgical instrument 10 specifically for thermal cutting of biological tissues in patients. The instrument 10 includes two jaws 15, 16, wherein at least one of the jaws 15 is configured to move toward and away from the other jaw 16. At least one of the jaws 15 includes a thermal cutting element 22 having a conductive cutting conductor 36 and a conductive return conductor 37 electrically connected to each other. The cutting element 22 is arranged such that the cutting conductor 36 is thermally exposed on at least the side of one jaw 15 facing the other jaw 16, and the return conductor 37 is surrounded by an insulator 34. The return conductor 37 has a lower resistance than the cutting conductor 36 in the direction of current flow and preferably a higher thermal conductivity than the cutting conductor 36. In doing so, considerably less heat and temperature are generated at the return conductor 37 than at the cutting conductor 36 during current supply to the cutting element 22, and the return conductor 37 can be used for heat dissipation.

[0062] List of reference numerals 10 Electrosurgical instruments 11. Handle 12. Proximal end of the instrument 13. The distal end of the instrument 14 Tools 15 First gripper 16 Second gripper 17 Handle 18 power supply lines 19. Equipment Supply Line 20. Supply equipment 21 Pivot axis 22 Cutting components 23 Support portion of the first gripper 24. Outer side of the support portion 25 Edge area of ​​the gripper 26,27 Sealing electrode of the first gripper 28. Distal end section of the gripper 29 Support portion of the second gripper 30,31 Sealing electrode of the second gripper 32. Area near the connector 33 Groove of the first gripper 34 Insulators 35. Groove of the second gripper 36. Cutting the conductor 37 Return conductor 38 Connecting elements 39 Spacer elements 40 positioning protrusions 41 Attachment protrusion 42. Undercut section 43 Coating 44. Undercut section of insulator foot 45. Tapered section of the insulator foot 46. ​​Opening in the support portion of the first gripper 47. Depression 48 RF Generator 49 Transformer 50 counter pressure body 51 Insulator foot 52 Return to the conductor's core 53 Lateral stop 54 Return to conductor cavity 55 base plate 56 Transverse cavity 57 Longitudinal cavity 58 Support surface A36 Cross-sectional area of ​​the cut conductor A37 Returns the cross-sectional area of ​​the conductor.

Claims

1. An electrosurgical instrument (10) specifically for thermal cutting of biological tissue, having at least two jaws (15, 16), wherein at least one of the jaws (15, 16) is configured to move toward and away from the other jaw (16, 15), wherein at least one of the jaws (15, 16) includes a thermal cutting element (22) having a conductive cutting conductor (36) and a conductive return conductor (37) connected to said cutting conductor (36). The cutting element (22) is arranged such that the cutting conductor (36) is at least partially thermally exposed on the side of at least one jaw (15) facing the other jaw (16), and the return conductor (37) is surrounded by an insulator (34). The return conductor (37) has a lower resistance than the cut conductor (36).

2. The electrosurgical instrument (10) according to claim 1, characterized in that, The return conductor (37) has a higher thermal conductivity than the cutting conductor (36).

3. The electrosurgical instrument (10) according to claim 1 or claim 2, characterized in that, The cutting conductor (36) and the return conductor (37) are a single unit, which is preferably constructed at least substantially in a U-shape.

4. The electrosurgical instrument (10) according to claim 3, characterized in that, The cutting conductor (36) and the return conductor (37) are thermally and electrically connected to each other in a section preferably arranged in the distal end section (28) of the gripper (15).

5. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, The core (52) of the return conductor (37) is at least partially provided with a coating (43), wherein the coating (43) is preferably made of a material having a lower specific resistivity and / or a higher specific thermal conductivity than the base material of the cutting element (22).

6. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, The cutting conductor (36) has a larger cross-sectional area than the return conductor (37).

7. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, The grippers (15, 16) include at least one sealing electrode (26, 27) in the edge region (25), wherein the at least one sealing electrode (26, 27) is spaced from the cutting conductor (36), wherein, in the lateral side, the cutting conductor (36) is preferably surrounded by the sealing electrode (26, 27) between the distal and proximal ends of the grippers (15) and / or in the distal end section (28) of the grippers (15).

8. The electrosurgical instrument (10) according to claim 7, characterized in that, Another gripper (16) includes at least one sealing electrode (30, 31) in the edge region (25), wherein the at least one sealing electrode (30, 31) is arranged in the same manner as the sealing electrode (26, 27) of the first gripper (15).

9. The electrosurgical instrument (10) according to claim 8, characterized in that, The sealing electrodes (26, 27; 30, 31) are positioned above each other, but are spaced apart when the grippers (15, 16) are closed.

10. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, The insulator (34) is made of an electrically insulating material and includes a material with a lower thermal conductivity than the cutting element (22).

11. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, At least one attachment protrusion (41) is formed on the cut conductor (36), wherein the at least one attachment protrusion (41) is surrounded by the insulator (34), wherein the at least one attachment protrusion (41) preferably includes an undercut section (42) surrounded by the insulator (34).

12. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, At least one spacer element (39, 39a, 39b, 39c) is arranged between the cutting conductor (36) and the return conductor (37), wherein the at least one spacer element is made of an electrically and thermally insulating material.

13. The electrosurgical instrument according to claim 12, characterized in that, The at least one spacer element (39) includes an upper side and a lower side, wherein the spacer element (39) preferably contacts the cutting conductor (36) on the upper side and / or contacts the return conductor (37) on the lower side.

14. The electrosurgical instrument (10) according to claim 12, characterized in that, The at least one spacer element (39a, 39b, 39c) includes a return conductor cavity (54) in which the return conductor (37) is arranged such that the return conductor is at least partially surrounded and held by the spacer element (39a, 39b, 39c).

15. The electrosurgical instrument (10) according to claim 14, characterized in that, The at least one spacer element (39a, 39b, 39c) includes a support surface (58) on which the cut conductor (36) is placed, wherein the spacer element (39a) includes at least one lateral stop (53) that protrudes from the support surface (58) and the cut conductor is laterally abutted against the at least one lateral stop (53).

16. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, Another gripper (16) includes a counterweight (50) arranged on a side facing one of the grippers (15), and the counterweight (50) there defines a counterweight surface for the cut conductor (36) of the one gripper (15).

17. The electrosurgical device (10) according to any one of the preceding claims, characterized in that, The cut conductor (36) protrudes from the surface formed by the insulator (34) in a direction toward the other gripper (16).

18. The electrosurgical instrument (10) according to claim 16 or claim 17, characterized in that, When the grippers (15, 16) are closed, the counter-pressure body (50) and the cutting conductor (36) overlap along the cutting conductor (36), preferably at a uniform depth, wherein the cutting conductor (36) penetrates the counter-pressure body (50).

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