WO2017025070A1

WO2017025070A1 - Surgical vapourisation electrode

Info

Publication number: WO2017025070A1
Application number: PCT/DE2016/000256
Authority: WO
Inventors: Christoph Knopf; Christian Brockmann; Thomas Freitag
Original assignee: Olympus Winter & Ibe Gmbh
Priority date: 2015-08-07
Filing date: 2016-06-22
Publication date: 2017-02-16
Also published as: DE102015010306A1

Abstract

The connection line (3) and the curved working surface (2) of the vaporisation electrode are electrically connected to one another. An electrode region (5) is provided in the electrode head (1) and recessed in relation to the working surface (2), and which is circumferentially bordered by a section of the working surface (2). An electrically conductive electrode element (6) is arranged in the recessed electrode region (5), said electrode element being electrically connected to the connection line (3), being configured as a spike, and having a free end (7). The free end (7) is convexly curved and has a local radius of curvature (r), which is substantially smaller than the radius of curvature (R) of the substantially hemispherical working surface (2).

Description

SURGICAL VAPORIZATION ELECTRODE

Technical area

The invention relates to a surgical vaporization electrode.

State of the art

Electric surgical resection tools are known from the prior art, in the use of which for resection high-frequency (HF) alternating current is passed through the body part to be treated in order to selectively remove or cut the corresponding tissue locally. Such resection tools are used in particular to provide e.g. to remove adenomatous tissue by vaporization. For this purpose, an RF voltage is applied to an electrode, which is generated by means of suitable RF generators and connected via appropriate feeds to the working part of the electrode, wherein such electrodes can be operated bipolar or monopolar depending on the training. Most commonly used is the monopolar technique, where one pole of the RF voltage source is connected to the patient over the largest possible area as a neutral electrode and the surgical instrument (active electrode) forms the other pole. The current flows through the path of least resistance from the active electrode to the neutral electrode, so that in the immediate vicinity of the active electrode, the current density is highest. Consequently, the thermal effect is most pronounced here, but also adjacent tissue is heated by current flow. In bipolar technology, in contrast to the monopolar technique, the current only flows through a small part of the body. The localized current density at the bipolar electrode causes a rapid heating of the tissue surrounding the electrode tips with consecutive vaporization of the tissue water or the rinsing fluid surrounding the tissue (irrigating solution, saline). A thin gas layer (vapor cushion) forms around the tip of the electrode, which can be ionized at a sufficiently high voltage (plasma ignition) to form a constant plasma. The energy of the plasma is transferred to the cells of the tissue to be resected and leads to its localized vaporization. Through plasma vaporization can a

Tissue can be separated and removed more gently and effectively than with conventional ones Vaporisation (eg by means of monopolar vaporization or by laser evaporation), since the plasma vaporization only requires the contact between electrode and tissue to a minimum and does not require high temperatures ("cold vaporisation").

From US 2003/0130653 AI a Vaporisationselektrode with convex curved work surface is known.

In DE 102007054438 AI a surgical vaporization electrode is described with a preferably hemispherical electrode head, wherein the electrode head has a curved work surface and at least one connection point which is connected to a sheathed with an insulating lead wire. The surface area of the electrode head surrounding the connection point is provided with an insulating ceramic cover. The cover prevents plasma from forming at other locations of the electrode head than the working surface. Due to their ceramic execution, the cover is thermally and chemically highly stable.

From WO2013070311 AI a bipolar surgical resection tool is known, which is formed either with a hemispherical or with an oval button electrode. The latter has an axial length in the working direction which corresponds to that of the hemispherical button electrode, while its (lateral) width extension is markedly lower, so as to achieve an improved tissue vaporization rate.

Depending on the size and shape of the surface of the vaporization electrode, the setting of the RF generator, the tissue impedance, the temperature of the rinsing fluid and the size of the tissue contact area, the ignitability of the plasma changes. In an unfavorable parameter constellation, direct plasma ignition during generator activation is not possible, e.g. an activation in free rinsing liquid (saline solution). Nevertheless, in order to generate a constant plasma, repeated high electrical energies must be repeatedly introduced in order to change the parameters so that a plasma ignition is possible. These pulsations can lead to a massive increase in the temperature of the rinsing fluid, which poses a risk to the patient when exceeding certain limits.

Presentation of the invention

Based on the aforementioned devices of the prior art, the present invention seeks to provide a device which the mentioned disadvantages or at least to a lesser extent. In particular, a vaporization electrode is to be created which allows an immediate, largely independent of the framework conditions plasma ignition upon activation of the RF generator.

The invention relates to a surgical vaporization electrode which has an electrical connecting line and an electrically conductive working surface electrically connected thereto. An electrode area bordered on at least two sides by a section of the working surface is set back from the working surface. In the recessed electrode region, an electrically conductive Elektrodenlement electrically connected to the connecting line is arranged, which has a free end.

Preferably, the work surface, for example, substantially corresponding to a spherical section or an ellipsoid, convex curved, but the work surface can also be made even. Inwardly curved areas of the surface forming the work surface, for example at the interface between the work surface and the recessed electrode area, are not attributed to the work surface. Due to the curvature of the angle between the electrode or electrode center axis and tissue can vary, without significantly affecting the Resektionswirkung. This results in easier handling.

At at least one point of the electrode element, this has a greater curvature than the curvature of the working surface. Stronger curvature is to be understood in particular as meaning that the electrically conductive electrode element has a (local) curvature radius at at least one location, preferably at its free end, which is smaller than the minimum (local) curvature radius of the working surface, particularly preferably less than or equal to zero , 5 mm. Accordingly, the free end of the electrode element is preferably convexly curved or conical. If the work surface is flat, then each circle of oscillation degenerates to the straight line and the radius of curvature of the work surface is infinitely large.

An inventively designed Vaporisationselektrode allows the instantaneous ignition of the plasma on, for example, pin, pin or pin-like electrode element in the recessed electrode area, as on small surfaces or on surfaces with small radii of curvature at the same voltage a higher electric field strength is generated (peak discharge effect). The thus generated higher current density at the electrode element can produce the gas pocket necessary for the plasma ignition around the vaporization electrode more quickly, more stably and with less expenditure of energy even under less favorable conditions, eg when activated in free rinsing liquid. By the lesser Energy input is increased at the ignition of the temperature of the rinsing liquid far smaller than in a conventional button-shaped vaporization.

The areal extent of the electrically conductive electrode element is preferably chosen such that its area extent is in any case smaller than the area extent of the working area, preferably smaller than or equal to one fifth, particularly preferably smaller than or equal to one tenth, of the area extent of the working area when the working area is viewed in a projection plane becomes, in which their surface area is maximum. For example, in the case of a substantially hemispherical work surface, such a projection plane is parallel to the ball cut surface.

In the preferred embodiment of the vaporization electrode according to the invention, in which the surface area of the electrically conductive electrode element is less than or equal to one fifth or even one tenth of the surface area of the working surface in said projection, the peak discharge effect occurs increasingly. In addition, the recessed electrode area can be dimensioned smaller, which allows a larger and more uniform work surface. As a result, a large resection surface with uniform plasma propagation with easily controllable vaporization can be achieved while at the same time providing good ignitability.

According to an advantageous development, the vaporization electrode may, in addition to the set-back electrode area, also have one or more further set-back electrode areas, which in turn are bounded on at least two sides by a section of the working surface, and in each of which a (further) electrically conductive electrode element with a free end is arranged is.

According to a preferred embodiment, the working surface and / or the electrically conductive electrode element is metallic. Preferably, the metallic material of the electrically conductive electrode element according to the electrochemical series of voltages is more noble than the metallic material of the working surface. A faster wear of the electrode element by the increased plasma activity is thus reduced or prevented.

In a further advantageous embodiment, the free end of the electrically conductive electrode element at least does not protrude beyond the bounding portion of the working surface. As a result of its arrangement, which is restricted to the recessed electrode region, the electrode element is not subject to any direct mechanical stresses during resection of the tissue, as a result of which the risk of fracture can be reduced. At the same time, an instantaneous, uniform vaporization of the liquid film surrounding the working surface can be achieved.

In a particularly preferred embodiment, the free end of the conductive electrode element is set back from the bounding portion of the working surface. The risk of breakage or other damage to the slender, for example mandrel, pin or pin-shaped electrically conductive electrode element can thus be further reduced, the instantaneous, uniform vaporization of the liquid surrounding the working surface is maintained.

In a preferred development of the vaporization electrode according to the invention, the set-back electrode region is peripherally bounded by the corresponding section of the working surface. The conductive electrode element is thus better protected against damage. The peripheral boundary also reduces the number and length of protrusions and edges on the electrode head, and thus also reduces the number and length of locations where high density current can pass from the electrode head to the vaporization fluid or tissue , As a result, more uniform vaporization of the liquid film surrounding the work surface occurs.

As an alternative to the peripheral boundary, according to a further advantageous embodiment of the vaporization electrode, the bounding portion of the working surface may be interrupted. Thus, the work surface can be divided into two or more parts, which can bring manufacturing advantages. The interruption is chosen so that the uniform vaporization of the liquid surrounding the work surface is not hindered, but at the same time the access to the electrically conductive electrode element is facilitated. This may also be advantageous for cleaning the work surface, the recessed electrode area, and the electrode element after use.

According to a further advantageous embodiment, the set-back electrode region can be designed as a recess in the working surface. A vaporization electrode designed in this way allows a simplified production process in that the recess can be drilled, sawn, milled, stamped, etched or produced as a gap between two or more juxtaposed electrode parts, for example.

In a further embodiment, the recessed electrode region is designed as a (in particular concave) concavity of the surface which also forms the working surface.

For example, in the manufacture of the vaporization electrode of the recessed Electrode area can be generated by a corresponding casting process, by means of a convex-shaped punch or by ablation.

A combination of these two possibilities is advantageously possible, i. E. the surface, which also forms the working surface, can be curved inwards at the transition to a recess in which the electrode element is seated.

In general, the electrically conductive electrode element and the working surface can be machined out of a common workpiece, or else the electrically conductive electrode element is manufactured separately and inserted into the recessed electrode region.

In an advantageous development of the vaporization electrode according to the invention, a connection point is provided which is arranged between the electrical connection line and an electrode head which has the working surface, the recessed electrode region and the electrically conductive electrode element. A surface region of the electrode head surrounding the connection point can preferably have an insulating cover. Since plasma can form on all electrically conductive surfaces of the vaporization electrode and not only on the work surface, the insulating cover advantageously prevents plasma from forming on the connecting lead to the electrode head and on its insulating jacket and thus on the one hand the connecting lead or the insulating material surrounding it damaged, and on the other hand, the tissue vaporization is less controllable.

Particularly preferably, the insulating cover to a ceramic material. Due to the heat resistance of the ceramic material, the connection lead to the electrode head can be optimally protected against the effect of heat by the plasma.

The invention will be explained in more detail below by way of example with reference to the accompanying schematic drawing. The drawings are not to scale; In particular, ratios of the individual dimensions do not necessarily correspond to one another for reasons of clarity, the dimensional ratios in actual technical implementations. There are described several preferred embodiments to which the invention is not limited. In principle, any variant of the invention described or indicated in the context of the present application may be particularly advantageous, depending on economic, technical and possibly medical conditions in the individual case. Unless otherwise stated, or as far as technically feasible, individual features of the described embodiments are interchangeable or combined with each other and with per se known from the prior art features.

Brief description of the figures

Figure la shows an exemplary embodiment of a surgical inventive

Vaporization electrode in cross section, in which the recessed electrode region is designed as a recess. The area of the free end of the electrically conductive electrode element is also shown in an additional enlarged partial view.

FIG. 1b shows the vaporization electrode in plan view, which is equivalent to the projection of the working surface and of the conductive electrode element in the projection plane A-A 'in FIG. The area of the free end of the electrically conductive electrode element is also shown in an additional enlarged partial view.

FIG. 2 shows, similar to FIG. 1a, a vaporization electrode in cross-section, whereby, however, the recessed electrode region is designed as a concave concavity of the surface which also forms the working surface

FIGS. 3 a, b show various alternative embodiments of the electrode head of FIG

Vaporisation electrode in plan view similar to Fig. Lb.

Preferred embodiment of the invention

Corresponding elements are denoted by the same reference numerals in the drawing figures.

Fig. 1 shows the electrode head 1 of a surgical vaporization electrode, which may be constructed in its other components as conventional from the prior art, for example DE 102007054438 AI, known vaporization.

The work surface 2 consists of a suitable, high temperature resistant metal, as it is also used in vaporization electrodes according to the prior art. In the exemplary embodiment, the work surface 2 is formed substantially hemispherical, but may also have another, for example, ovaloid or ellipsoid, basic shape. (The imaginary continuation of the hemispherical basic shape over the recessed electrode region 5 is indicated by means of a thin dashed line.)

The electrode head 1 is supplied with voltage via an electrical connection line 3, which is provided with an insulating jacket 4 made of plastic. The connecting line 3 and the curved work surface 2 are electrically connected to each other. In the electrode head 1 of the opposite the working surface 2 set back, formed by a recess electrode portion 5 is provided, which is peripherally bounded by a portion of the working surface 2. While in the illustrated Variente the circumferential edge of the recessed electrode portion 5 has an edge, an alternative variant is indicated by a dashed line on the right side of the section in Fig la through the recess: At the transition between the recess and the work surface 2 can which also the work surface 2 forming surface 2 'inward arch.

In the recessed electrode region 5, an electrically conductive electrode element 6, which is likewise electrically connected to the connection line 3 and has a thorn-like design, is arranged with a free end 7. The free end 7 is curved convexly and has a local radius of curvature r, which is significantly smaller than the radius of curvature R of the substantially hemispherical working surface second

The electrically conductive electrode element 6 has - as viewed in the projection plane AA ¹ , in which the surface extent of the work surface 2 with respect to other projection planes is maximum - a surface area less than one-tenth of the surface area of the work surface 2. The projection level AA 'is any of the spherical section 8 parallel Level. The electrode element 6 is welded at the weld 9 in the recessed electrode region 5 by means of laser welding, but can also be connected by means of other joining techniques, such as soldering, or be formed from the same workpiece as the working surface. 2

As a result of the electric field strength with less expenditure of energy, a gas pocket for the generation of constant plasma forms around the electrode element 6 in the recessed electrode region 5. The electrode element 6 is dimensioned so that its free end 7 is set back relative to the working surface 2, that is, does not protrude beyond the bounding portion of the working surface 2.

The electrical connection line 3 is connected to a connection point 10 on the electrode head 1, for example, welded or soldered. The rear surface of the electrode head 1, which forms the spherical section 8, is flat and has an insulating surface Cover 11 covered by ceramic material. The insulating cover 1 1 has a bore 12 through which the electrical connection line 3 passes.

While the recessed electrode region 5 is designed as a recess in the working surface 2 in the exemplary embodiment illustrated in FIGS. 1a and 1b, the recessed electrode region 5 is formed in the embodiment shown in FIG. 2 by a concave concavity of the surface 2 'which also forms the working surface 2 , The electrically conductive electrode element 6 is embodied here in one piece together with the working surface 2 and is shaped in a substantially conical or pin-like manner. The electrode head 1 is shown hollow in FIG. 2, but can also be embodied as a solid body as in FIG. 1 a. The small radius of curvature r at the free end 7 of the peg-like electrode element 6 in turn favors the tip discharge effect for plasma ignition. The (smallest) radius of curvature R of the substantially hemispherical working surface 2 is substantially greater than the radius of curvature r at the free end 7 of the pin-like electrode element 6. The imaginary continuation of the hemispherical basic shape is again indicated by a thin dashed line.

FIGS. 3 a and 3 b show various embodiments of a curved electrode head 1 of a vaporisation electrode in plan view, similar to FIG. 1 b. At the same time, the representation corresponds in each case to a projection in which the areal extent of the (projected) work surface 2 is at a maximum

The working surface 2 is divided in each case by the recessed electrode portion 5 in two substantially equal sections, whereby the bounding portion of the working surface 2 is interrupted. The electrically conductive electrode element 6 is again arranged centrally in the recessed electrode region 5. FIG. 3 a again shows a pin-like or spike-like design of the electrode element 6, while the electrode element in FIG. 3 b has the form of an elongate narrow plate or blade.

Claims

1. Surgical vaporization electrode, comprising an electrical connecting line (3),

a planar or convexly outwardly curved, electrically conductive working surface (2) electrically connected to the connection line (3), an electrode region (5) set back from the working surface (2) on at least two sides and opposite the working surface (2) , and

an electrically conductive electrode element (6) arranged in the set-back electrode region (5) and electrically connected to the connection line and having a free end (7),

wherein the electrically conductive Elektrodenlement (6) in at least one location has a local radius of curvature, which is smaller than the smallest local radius of curvature of the work surface (2).

2. Surgical Vaporisationselektrode according to claim 1, wherein the free end of the (7) of the electrically conductive electrode member (6) is convex.

3. Surgical Vaporisationselektrode according to any one of the preceding claims, wherein the free end (7) of the electrically conductive electrode member (6) over the bordering portion of the working surface (2) at least not protrudes.

4. The surgical vaporization electrode according to claim 3, wherein the free end (7) of the conductive electrode element (6) is set back relative to the bounding portion of the working surface (2).

5. Surgical Vaporisationselektrode according to any one of the preceding claims, wherein the bounding portion of the working surface (2) surrounding the recessed electrode portion (5) circumferentially.

6. A surgical vaporization electrode according to any one of claims 1-4, wherein the bounding portion of the work surface (2) is interrupted.

A surgical vaporisation electrode according to any one of the preceding claims, wherein the recessed electrode portion (5) is formed by a recess in the working surface (2).

A surgical vaporisation electrode according to any one of the preceding claims, wherein the recessed electrode portion (5) is formed by an inward curvature of a surface forming the working surface (2).

9. Surgical Vaporisationselektrode according to one of the preceding claims, wherein in a planar projection (Α-Α ') in which the surface extent of the working surface (2) is maximum, the surface area of the electrically conductive electrode member (6) is less than or equal to one fifth of the surface area the work surface (2) is.

10. The surgical vaporization electrode according to claim 1, wherein the vaporization electrode has a connection point between the electrical connection line and an electrode head having the working surface, 1), and a surface area of the electrode head (1) surrounding the connection point (10) has an insulating cover (11).

11. A surgical vaporization electrode according to claim 10, wherein the insulating cover (1 1) comprises a ceramic material.