DE102021210726A1 - Part of an electrosurgical instrument - Google Patents

Abstract

The invention relates to a part of an electrosurgical instrument, having a tissue side on which at least one sensor structure (20) is arranged. The sensor structure (20) has four electrodes (21a, 21b, 22a, 22b).

Description

The present invention relates to a part of an electrosurgical instrument. In addition, the present invention relates to an electrosurgical instrument having the part.

State of the art

Bleeding is unacceptable in minimally invasive surgery because the surgical site is not accessible with a swab, for example. Therefore, electrosurgery is used in this area in particular, in which the tissue is sclerosed or first coagulated and/or thermofused before the cut. The tissue is thermally heated by a high-frequency current flow and the proteins coagulate and tissue fluid or water is expelled from the affected tissue section. This enables a reliable closure of the blood vessels before the surgical incision.

Coagulation takes place in a temperature range of 60° to 80° C and thermofusion in a temperature range of 90° to 100° C. If the temperature reached is below this, there is a risk of unwanted bleeding. At even higher temperatures, the coagulated or thermofused tissue is damaged to such an extent that solid scars form or the tissue burns, which has a negative effect on the healing process. However, it is not possible to measure the temperature directly on the coagulated tissue; instead, the temperature reached is only indirectly estimated by measuring the impedance of the high-frequency generator.

Disclosure of Invention

The part of an electrosurgical instrument has a tissue side. A tissue side is understood to mean a side that is provided and set up to face organic tissue when the part is used. At least one sensor structure is arranged on the fabric side. This sensor structure has four electrodes. The sensor structure can be used in particular to determine at least one electrical parameter of the organic tissue to be treated during coagulation or thermofusion using the electrosurgical instrument. A sensor structure with four electrodes is particularly advantageous for measuring bioimpedances in different organic tissue types and tissue structures. An AC resistance, a current curve and a voltage curve can be determined by the four poles of the sensor structure. The bioimpedance measurement can be frequency-dependent. In this way, it is possible to identify an organic tissue type, such as muscle tissue, fatty tissue, tissue traversed by nerves or tissue traversed by blood vessels, directly from its electrical resistance behavior. The tissue moisture or the tissue fluid state, ie its intracellular and extracellular fluid, can be recorded by measuring the electrical tissue conductivity. This in situ detection of the tissue type and the tissue condition based on the moisture measurement allows an operation to be performed using the electrosurgical instrument with increased operational safety.

All four electrodes of a sensor structure are preferably arranged coplanar or plane-parallel to one another in order to enable reliable determination of AC resistance, current curve and voltage curve. In principle, it is possible to provide further electrodes in addition to these four electrodes in a sensor structure for the purpose of further analyses. These need not be arranged coplanar or plane-parallel to the four electrodes.

It is preferred that the sensor structure has two first electrodes and two second electrodes. In this case, the first electrodes can be used in particular for a current measurement and the second electrodes can be used in particular for a voltage measurement. For this purpose, an area ratio between the first electrodes and the second electrodes is preferably at least 2.5:1.

For a reliable AC measurement, the distance between the first two electrodes should be at least six times the tissue depth to be measured. In order to ensure moisture determination in tissue depths that are relevant in practice, this distance is preferably at least 1,500 μm and particularly preferably at least 1,800 μm.

A distance from a first electrode to an adjacent second electrode is preferably constant over the entire width of the electrodes. The width is understood to be the dimension of the electrodes along which the first electrode faces the second electrode. In the simplest case, this constant distance can be realized in that the first electrode and the second electrode are each embodied in an elongated manner and run parallel to one another. It is preferred here that the electrodes are arranged symmetrically to one another in order to generate a homogeneous electric field or a homogeneous course of electric field lines. In principle, however, other forms are also conceivable. For example, the two electrodes can have a U-shaped curved contour, the contour of one electrode being convex and the contour of the other electrode being concave. The electrodes preferably do not have sharp edges and partial peaks in order to avoid inhomogeneities in the electric field. In order to avoid electric field peaks, the edges of the electrodes can in particular be rounded and/or passivated.

The distance from a first electrode to an adjacent second electrode is preferably in the range from 100 μm to 300 μm. On the one hand, this ensures adequate electrical insulation between the first electrode and the second electrode. On the other hand, it is ensured that the current measurement and the voltage measurement take place locally so close together that a reliable determination of the bioimpedance of the tissue is possible.

In order to insulate the electrodes of the sensor structure electrically from one another even more effectively than is possible simply by spacing them apart, it is preferred for the sensor structure to be at least partially embedded in a covering layer. It is particularly preferably completely embedded in the covering layer. When treating organic tissue, this also prevents electric current from flowing from one electrode through the organic tissue into another electrode. This means that electrical conductivity measurement on the tissue is no longer possible. However, the sensor structure that is completely embedded in the cover layer can still be used to determine a capacitance/dielectricity or a bioimpedance of the organic tissue and thus to infer the tissue moisture.

In one embodiment of the part, the cover layer is openly porous. This allows moisture from the organic tissue to be absorbed into the open pores of the cover layer and thus allows a particularly effective bioimpedance measurement.

The cover layer preferably consists of a material selected from the group consisting of aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), YSZ (yttria stabilized zirconia; zirconium oxide partially stabilized with yttrium oxide (Y ₂ O ₃ ), silicon ( Si), silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), a parylene, a silicone, an epoxy resin and an insulating varnish. These materials have the advantage of having low electrical conductivity and being resistant to the high temperatures involved in coagulation or thermofusion.

In order to give the electrodes sufficient sensitivity, to make them resistant to the mechanical and thermal loads occurring in the electrosurgical instrument and at the same time to make them so thin that they do not impair the function of the electrosurgical instrument, their layer thickness is preferably in the range of 0, 0.5 µm to 20.00 µm and more preferably in the range of 0.10 µm to 6.00 µm.

The electrodes are preferably made of a material selected from the group consisting of platinum, platinum alloys, silver, silver alloys, gold, gold alloys, titanium nitride (TiN) and doped silicon. Gold, gold alloys, platinum and platinum alloys are particularly preferred, with platinum-palladium alloys being particularly preferred.

The part preferably has a coagulation and/or thermofusion electrode which is carried by a component carrier. A coagulation and/or thermofusion electrode is understood to mean an electrode which is set up for the coagulation and/or thermofusion of tissue. In this embodiment of the part, the sensor structure is advantageously arranged close to the coagulation and/or thermofusion electrode and can be installed together with this in an electrosurgical instrument.

The component carrier is preferably a ceramic component carrier. Ceramic materials are good electrical insulators that also have high thermal stability. This ensures that the component carrier cannot be damaged due to high temperatures of the coagulation and/or thermofusion electrode. Suitable ceramics are, in particular, aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) or YSZ. Alternatively, however, a polymer component carrier can also be used. This can in particular consist of polyetheretherketone (PEEK).

In a preferred embodiment of the part, it is provided that the at least one sensor structure is arranged on the coagulation and/or thermofusion electrode. Since the coagulation and/or thermofusion electrode is intended to be brought into direct contact with the organic tissue to be treated, this arrangement of the sensor structure makes it possible to take a measurement particularly close to the treatment site. In order to prevent electrical short-circuiting of the electrodes via the material of the coagulation and/or thermofusion electrode, it is provided that an electrical insulation layer is arranged between the sensor structure and the coagulation and/or thermofusion electrode net is. The thickness of the electrical insulation layer is preferably in the range from 0.05 μm to 15.00 μm, so that on the one hand there is sufficient insulation of more than 1,000 ohms to the coagulation and/or thermofusion electrode, but on the other hand the insulation layer is not made unnecessarily thick. Preferred materials of the insulation layer are selected from the group consisting of aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), YSZ, silicon (Si), silicon oxide (SiO ₂ ) and titanium oxide (TiO ₂ ). Aluminum oxide and silicon oxide are particularly preferred. These materials are not only good electrical insulators, they also have good thermal conductivity, so that the coagulation effect or thermofusion effect of the coagulation and/or thermofusion electrode at the position of the sensor structure is not significantly impaired by the electrical insulation layer.

For electrical contacting of a sensor structure arranged on the coagulation and/or thermofusion electrode, one embodiment of the part provides that a recess is made in the component carrier on a side of the coagulation and/or thermofusion electrode facing away from the tissue side. An electrical contact is routed from each electrode through the insulating layer and through the coagulation and/or thermofusion electrode into the recess. It is electrically insulated from the coagulation and/or thermofusion electrode. Additional contact can be provided in the recess, for example using an electrically conductive adhesive or metallic solder, on a flex film, on stranded wires or on a cable in order to connect the sensor structure to a medical instrument handle of the electrosurgical instrument and via this to an evaluation unit .

In another embodiment of the part, the coagulation and/or thermofusion electrode has at least one lateral recess. At least one electrical contact of an electrode is arranged in this recess. This enables the sensor structure to be contacted from the side of the coagulation and/or thermofusion electrode. If the part has multiple lateral recesses per sensor structure, then, for example, the electrical contacts of a pair of a first electrode and a second electrode can be arranged in one recess, and the electrical contacts of another pair of a first electrode and a second electrode of the same sensor structure can be placed in another recess.

If the coagulation and/or thermofusion electrode has two legs and several sensor structures are arranged on it, then it is preferred that the sensor structures of the two legs are arranged offset to one another. In this way, good area monitoring can be achieved by the sensor structures even when contacting narrow tissue areas with the coagulation and/or thermofusion electrode.

If the coagulation and/or thermofusion electrode has a U-shape, it is preferred that at least one sensor structure is arranged on its curved area. In this way, if only the tip of the coagulation and/or thermofusion electrode is used to grasp tissue and thus perform minimal tissue treatment, monitoring by at least one sensor structure can still take place.

In a further embodiment of the part it is provided that the at least one sensor structure is arranged on the component carrier and thus next to the coagulation and/or thermofusion electrode. This also enables a measurement close to the operating area, but no electrical insulation of the sensor structure from the coagulation and/or thermofusion electrode is required. In principle, the sensor structure can also be arranged on an electrical insulation layer in this embodiment, but this is not necessary.

An electrical contact is routed from each electrode of a sensor structure arranged on the component carrier, preferably through the component carrier to a side of the component carrier which is remote from the tissue side. Further contact can be made there.

The electrosurgical instrument has at least one part according to the aspect of the invention described above. In particular, the electrosurgical instrument can be designed in the form of forceps. The part is then arranged in a jaw part of a jaw of the electrosurgical instrument.

Two first electrodes of each sensor structure are preferably connected to a current measuring device and two second electrodes of each sensor structure are preferably connected to an electrical voltage measuring device. The current measuring device and the electrical voltage measuring device can in particular be arranged in an evaluation unit which is connected to the part via a medical instrument handle of the electrosurgical instrument.

character list

• 1 zeigt eine isometrische Darstellung eines Teils gemäß einem Ausführungsbeispiel der Erfindung.
• 2 zeigt eine schematische Darstellung einer Sensorstruktur eines Teils gemäß einem Ausführungsbeispiel der Erfindung.
• 3 zeigt eine schematische Darstellung einer Sensorstruktur eines Teils gemäß einem anderen Ausführungsbeispiel der Erfindung.
• 4 zeigt eine schematische Darstellung einer Sensorstruktur gemäß noch einem anderen Ausführungsbeispiel der Erfindung.
• 5 zeigt eine Querschnittsansicht einer Koagulations- und Thermofusionselektrode, die in einem Ausführungsbeispiel der Erfindung eine Sensorstruktur trägt.
• 6 zeigt eine Querschnittsdarstellung eines Teils gemäß einem Ausführungsbeispiel der Erfindung.
• 7 zeigt eine Aufsicht auf ein Teil gemäß einem Ausführungsbeispiel der Erfindung.
• 8 zeigt eine Aufsicht auf ein Teil gemäß einem anderen Ausführungsbeispiel der Erfindung.
• 9 zeigt eine Aufsicht auf ein Teil gemäß noch einem anderen Ausführungsbeispiel der Erfindung.
• 10 zeigt eine isometrische Darstellung eines Ausschnitts einer Koagulations- und Thermofusionselektrode, die in einem Ausführungsbeispiel der Erfindung eine Sensorstruktur trägt.
• 11 zeigt eine Querschnittdarstellung eines Teils gemäß noch einem anderen Ausführungsbeispiel der Erfindung.
• 12 zeigt eine schematische Darstellung eines elektrochirurgischen Instruments gemäß einem Ausführungsbeispiel der Erfindung.

Embodiments of the invention are shown in the drawings and are explained in more detail in the following description.

• 1 Figure 12 shows an isometric view of a part according to an embodiment of the invention.
• 2 FIG. 12 shows a schematic representation of a sensor structure of a part according to an embodiment of the invention.
• 3 12 shows a schematic representation of a sensor structure of a part according to another embodiment of the invention.
• 4 shows a schematic representation of a sensor structure according to yet another embodiment of the invention.
• 5 Figure 12 shows a cross-sectional view of a coagulation and thermofusion electrode carrying a sensor structure in one embodiment of the invention.
• 6 12 shows a cross-sectional view of a part according to an embodiment of the invention.
• 7 shows a top view of a part according to an embodiment of the invention.
• 8th 12 shows a plan view of a part according to another embodiment of the invention.
• 9 12 shows a plan view of a part according to yet another embodiment of the invention.
• 10 shows an isometric representation of a section of a coagulation and thermofusion electrode, which carries a sensor structure in an embodiment of the invention.
• 11 12 shows a cross-sectional view of a part according to yet another embodiment of the invention.
• 12 shows a schematic representation of an electrosurgical instrument according to an embodiment of the invention.

Embodiments of the invention

A part according to a first embodiment of the invention is shown in 1 shown. It has a ceramic component carrier 11, which consists of aluminum oxide in the present exemplary embodiment and carries a U-shaped coagulation and thermofusion electrode 12 with two legs. Five sensor structures 20 are arranged on the coagulation and thermofusion electrode 12, these being offset from one another along the two legs. A flex film 13 runs under the coagulation and thermofusion electrode 12 in a recess in the component carrier 11 for electrical contacting of the sensor structures 20. The part 10 is arranged in a jaw part 31 of an electrosurgical instrument.

A sensor structure 20 is in 2 shown. This has two rectangular first electrodes 21a, 21b and two rectangular second electrodes 22a, 22b. The first electrodes 21a, 21b each have an area of 1.6 mm ² . The second electrodes 22a, 22b each have an area of 0.6 mm ² . A distance d _21/22 between a pair of first electrode 21a, 21b and second electrode 22a, 22b is 0.2 mm in each case. A distance d ₂₁ between the two first electrodes 21a, 21b is 5.28 mm. A distance d ₂₂ between the two second electrodes 22a, 22b is 4.24 mm. Each first electrode 21a, 21b is connected to an electrical contact 23a, 23b, respectively. Each second electrode 22a, 22b is also connected to an electrical contact 24a, 24b, respectively.

3 shows in another embodiment of the invention that the first electrodes 21a, 21b compared to the second electrodes 22a, 22b can also have a significantly larger area and a smaller electrode spacing between the second electrodes 22a, 22b than is shown in FIG 2 is shown.

4 FIG. 12 shows, in yet another embodiment of the invention, that the facing edges of the electrodes 21a, 21b, 22a, 22b are not, as in FIGS 2 and 3 shown, must be linear, but can also be curved. It is shown here that a first electrode 21a has a concave edge, which faces a convex edge of a second electrode 22a. The other second electrode 22b has a concave edge which it faces a convex edge of its associated first electrode 21b. However, just as in the two previous exemplary embodiments, the two first electrodes 21a, 21b each have the same area and the two second electrodes 22a, 22b each have the same area. In addition, the distance d _21/22 between each first electrode 21a, 21b and the second electrode 22a, 22b facing it is constant over the entire electrode width, as in the exemplary embodiments described above.

A cross-sectional view of a leg of the coagulation and thermofusion electrode 12 according to FIG 1 is in 5 shown. The electrodes 21a, 21b, 22a, 22b of the sensor structure 20 are arranged on the coagulation and thermofusion electrode 12 that together with their elec rian contacts 23a, 23b, 24a, 24b are electrically isolated from the coagulation and thermofusion electrode 12 by means of an electrical insulation layer 25. In the present exemplary embodiment, the electrical insulation layer is 5 mm thick and consists of aluminum oxide. A pair of electrodes 21a, 22a and their electrical contacts 23a, 24a are surrounded by an open porous insulating layer 26 made of aluminum oxide. An electrical contact 231a, 231b, 241a, 241b is guided from each electrical contact area 23a, 23b, 24a, 24b through the coagulation and thermofusion electrode 12 to the opposite side thereof. It is surrounded by electrical insulation 332a, 332b, 342a, 342b, which consists of aluminum oxide in the present exemplary embodiment and electrically insulates it from the coagulation and thermofusion electrode 12.

6 shows the arrangement of the coagulation and thermofusion electrode 12 in the component carrier 11. The flex film 13 is arranged on the bottom of the recess 14 and is electrically connected to the electrical contacts 231a, 231b, 241a, 241b.

7 shows a top view of a part 10 according to a second embodiment of the invention. Unlike the part 10 according to the first exemplary embodiment, this has six sensor structures 20, which are not only arranged on the legs of the U-shaped coagulation and thermofusion electrode, but one of the sensor structures 20 is positioned in the curved area of the U-shape.

In a third embodiment of the invention, which is 8th As shown, the part 10 has two linear coagulation and thermofusion electrodes 12 which are arranged in parallel on the ceramic component carrier 11 . They are equipped with sensor structures 20 on their surface in the same way as the legs of the U-shaped coagulation and thermofusion electrode 12 in the first two exemplary embodiments of the invention.

9 shows a top view of a part 10 according to a fourth embodiment of the invention. Here, the component carrier 11 has only one linear coagulation and thermofusion electrode 12 with three sensor structures 20 arranged one behind the other on its surface.

10 shows a section of a coagulation and thermofusion electrode 12 of a part 10 in a fifth embodiment of the invention. The coagulation and thermofusion electrode 12 has two recesses 15a, 15b on one of its sides. The sensor structure 20 and its insulating layer 25 extend into the recesses 15a, 15b in such a way that two electrical contact areas 23a, 24a and 23b, 24b are arranged in each recess 15a, 15b. As a result, the sensor structure 20 can be electrically contacted from the side of the coagulation and thermofusion electrode 12 .

In a sixth embodiment of the invention in 11 is shown, a sensor structure 20 is arranged next to the coagulation and thermofusion electrode 12 on the component carrier 11 of a part 10 . The same electrical insulation layer 25 as in the first exemplary embodiment of the invention is arranged between the construction substrate 11 and the sensor structure 20 and their electrodes and electrical contact regions 23a, 23b, 24a, 24b. Two of the electrodes and their electrical contact areas 23a, 24a are covered by a covering layer 26, as in the first exemplary embodiment of the invention. Electrical contacts 231a, 231b, 241a, 241b, which are surrounded by insulation 232a, 232b, 242a, 242b, are from the electrical contact areas 23a, 23b, 24a, 24b through the insulating layer 25 and the component carrier 11 through to the coagulation and thermofusion electrode 12 facing away from the component carrier 11 out. There you can be contacted further electrically. The electrical contacts 231a, 231b, 241a, 241b and their insulation 232a, 232b, 242a, 242b are otherwise identical in construction to the electrical contacts 231a, 231b, 241a, 241b and their insulation 232a, 232b, 242a, 242b in the first exemplary embodiment of the invention .

12 shows an electrosurgical instrument 30, which is designed as a coagulation and thermofusion forceps. It has a first jaw part 31 and a second jaw part 32 which together form a mouth 33 . This is arranged on a shaft 34 that leads to an instrument handle 35 of the electrosurgical instrument 30 . The electrosurgical instrument 30 is connected via a connecting line 36 to evaluation electronics 40 which have an ammeter 41 and an electrical voltage meter 42 . The first electrodes 21a, 21b of the sensor structures 20 of the electrosurgical instrument 30 are connected to the current measuring device 41, and the second electrodes 22a, 22b of the sensor structures 20 are connected to the voltage measuring device 42. Each of the jaw parts 31, 32 has a part 10 which, in the 1 shown manner is arranged in this. The part 10 can be designed according to any of the exemplary embodiments of the invention described above.

Claims (15)

Part (10) of an electrosurgical instrument (30) having a tissue side on which at least one sensor structure (20) is arranged, characterized in that the sensor structure (20) has four electrodes (21a, 21b, 22a, 22b). Part (10) after claim 1 , characterized in that the electrodes (21a, 21b, 22a, 22b) are arranged coplanar or plane-parallel to one another. Part (10) after claim 1 or 2 , characterized in that the sensor structure (20) has two first electrodes (21a, 21b) and two second electrodes (22a, 22b), wherein an area ratio of the first electrodes (21a, 21b) to the second electrodes (22a, 22b) at least is 2.5:1. Part (10) after claim 3 , characterized in that a distance (d ₂₁ ) between the first electrodes (21a, 21b) is at least 1,500 µm. Part (10) after claim 3 or 4 , characterized in that a distance (d _21/22 ) from a first electrode (21a, 21b) to an adjacent second electrode (22a, 22b) is constant over an entire width of the electrodes (21a, 21b, 22a, 22b). . Part (10) after one of claims 3 until 5 , characterized in that a distance (d _21/22 ) from a first electrode (21a, 21b) to an adjacent second electrode (22a, 22b) is in the range of 100 µm to 300 µm. Part (10) after one of Claims 1 until 6 , characterized in that the sensor structure (20) is at least partially embedded in a covering layer (26). Part (10) after one of Claims 1 until 7 , characterized in that it has at least one coagulation and/or thermofusion electrode (12) which is carried by a component carrier (11). Part (10) after claim 8 , characterized in that the sensor structure (20) is arranged on the coagulation and/or thermofusion electrode (12), an electrical insulation layer (25) being arranged between the sensor structure (20) and the coagulation and/or thermofusion electrode (12). . Part (10) after claim 9 , characterized in that in the component carrier (11) on a side of the coagulation and/or thermofusion electrode (12) facing away from the tissue side a recess (14) is made and an electrical contact (231a, 231b) of each electrode (21a, 21b, 22a, 22b) of the sensor structure (20) through the insulating layer (25) and through the coagulation and/or thermofusion electrode (12) into the recess (14). Part (10) after claim 9 , characterized in that the coagulation and/or thermofusion electrode (12) has at least one lateral recess (15a, 15b) in which at least one electrical contact (23a, 23b, 24a, 24b) of an electrode (21a, 21b, 22a, 22b) is arranged. Part (10) after claim 8 , characterized in that the sensor structure (20) is arranged on the component carrier (11). part after claim 12 , characterized in that an electrical contact (231a, 231b) of each electrode (21a, 21b, 22a, 22b) of the sensor structure (20) is guided through the component carrier (11) to a side of the component carrier (11) facing away from the tissue side . Electrosurgical instrument (30), comprising at least one part (10) according to one of Claims 1 until 13 . Electrosurgical instrument (30) according to Claim 14 , characterized in that the sensor structure (20) of the part (10) has two first electrodes (21a, 21b) and two second electrodes (22a, 22b), the first electrodes (21a, 21b) being connected to an ammeter (41). and the second electrodes (22a, 22b) are connected to an electrical voltage measuring device (42).

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