Plasma probe and method for assembling electrodes thereof

Abstract

To provide a plasma probe which is stable for a long period, by a simple method.SOLUTION: A plasma probe 11 comprises: a hose 15 having a proximal end 16 and a distal end 17 having at least one lumen formed therebetween; a conductor which is disposed inside the hose 15, extends from the proximal end 16 to the distal end 17 of the hose 15, and includes a plastic sheath; and an electrode including an end electrically coupled to the conductor and an end extending in a distal direction. The electrode is held with the conductor and / or the plastic sheath of the conductor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The subject of the present invention is a plasma probe, in particular an argon plasma probe, and a method for assembling the electrodes of this plasma probe. [Background technology]

[0002] Electrosurgical instruments with electrodes that directly act on tissue are known. For example, Patent Document 1 discloses a high-frequency tool with an electrode realized as a resection loop. The U-shaped electrode is inserted at its two ends into respective holders, through which a supply wire is guided. The electrode is either crimped or welded to the supply wire, but in either case, a strong mechanical connection is achieved. The conductor insulation of the electrical supply line thereby extends beyond the end of the electrode, insulating it from the outer jacket.

[0003] From US Pat. No. 5,629,549 a tubal coagulation device is known, which comprises an attachment with a number of electrodes at its distal end. These electrodes are connected to a coaxial supply line by a coaxial plug. The arrangement consisting of the supply line and the plug is free to move axially within the working channel of the endoscope.

[0004] Furthermore, there are plasma probes that essentially consist of a hose connectable to a gas source, the distal end of the hose being open and serving to emit a plasma jet. An electrode is arranged at the distal end of the hose, typically held by an electrode holder, e.g., a small metal plate extending diametrically through the lumen of the hose. The electrode extends proximally through the lumen of the hose in the form of a wire and can be connected to a power source to generate an electric discharge at the distal end. Plasma probes constructed according to this principle are further known from US Pat. No. 5,699,299, US Pat. No. 5,799,299 or US Pat. No. 5,899,299.

[0005] The plasma flow that strikes the tissue to be treated originates from the electrode of the plasma probe. Since the electrode is located at the distal end of the hose, at least a portion of the generated thermal energy also reaches the peripheral wall of the distal end of the hose. To protect the hose, a ceramic sleeve can be placed thereon, as is known, for example, from the aforementioned Patent Document 6. However, the central support of the electrode is provided by a metal plate that transfers heat to the hose, which can result in the loss of central support during longer operating periods. This is particularly true since the electrode must be firmly connected to the plate to ensure significant heat transfer from the electrode to the metal plate. This problem is even more pronounced when the metal plate itself functions as the electrode, as proposed, for example, in Patent Document 4. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2017 / 076721 [Patent Document 2] European Patent Application Publication No. 1568325 [Patent Document 3] German Patent Application Publication No. 102017127976 [Patent Document 4] German Patent No. 10030111 [Patent Document 5] European Patent Application Publication No. 3769707 [Patent Document 6] International Publication No. 2005 / 046495 Summary of the Invention [Problem to be solved by the invention]

[0007] Starting from there, the aim of the present invention is to provide a concept which allows to provide a long-term stable plasma probe in a simple manner, for which particular attention must be paid to the assembly of the electrodes. [Means for solving the problem]

[0008] This object is solved by a plasma probe according to claim 1 and a method according to claim 15.

[0009] A plasma probe according to the present invention comprises a flexible hose made of a plastic material, which may include, for example, one or more lumens, each extending from a proximal end to a distal end. The lumens serve to convey a suitable gas, preferably an inert gas such as argon, from the proximal end to the distal end. The lumens of the hose are open at the distal end to allow the gas to flow out.

[0010] Disposed within the hose is an electrical conductor, which preferably extends the entire length of the hose from the proximal end to the distal end and is connected to an electrode at the distal end. The electrical conductor is provided with a plastic sheath at least at the distal end. The plastic sheath can be made of the same plastic as the hose, although a different plastic can also be provided.

[0011] The electrode is preferably a straight, needle- or rod-shaped electrode having a proximal end and a distal end. The electrode is hollow over all or at least a portion of its length, i.e., the electrode includes an internal channel forming a hollow space that is open at both ends or closed at the distal end. The conductor extends into this hollow space with play at its distal end. This allows the electrode to be supported by the conductor and, in some embodiments of the invention, by the conductor's plastic sheath. The electrode can be positioned such that its proximal end extends within the conductor's plastic sheath and is axially secured by the plastic sheath. In an unused state, the securing of the plastic sheath to the electrode can be achieved by a friction fit. After initial use, the plastic sheath can be fused to the electrode, thereby adhesively bonding the electrode to the electrode so that the proximal end of the electrode and the plastic sheath are materially joined.

[0012] The conductor preferably extends into the electrode with a loose fit. Because there is always a slight undulation or bend in the conductor, or even because the conductor and electrode are imperfectly aligned, the conductor and electrode are always in electrical contact. Furthermore, because the RF voltage applied to the conductor is very high, the potential gap between the conductor and electrode can be easily bridged by current. After initial use, a slight material flow between the conductor and electrode may occur at the contact site, forming a material bond similar to a solder or welded joint.

[0013] Whether or not the electrode extends within a plastic sheath, the electrode can be slightly deformed radially inward, e.g., by squeezing or crimping, to secure it to the conductor. Such deformation can occur at the distal end of the electrode, the proximal end of the electrode, or somewhere in between, with the conductor extending distally at least beyond the deformation region.

[0014] A plasma probe constructed according to this concept can be easily manufactured by providing a hose having a proximal end and a distal end with at least one lumen formed therebetween, the hose extending from the proximal end to the distal end of the hose, and a conductor including a plastic sheath disposed within the hose; optionally, removing the plastic sheath from a distal portion of the hose to expose the hose; providing an electrode having at least a hollow end; and pressing the hollow end of the electrode against the end of the conductor, preferably released from the plastic sheath, and inserting the hollow end of the electrode into the plastic sheath of the conductor. Thus, the electrode can be inserted and secured to the plasma probe in a single assembly step, simply by inserting it into the preferably exposed end of the conductor and, if necessary, into the gap opening between the conductor and the plastic sheath. This expansion of the plastic material causes the plastic material to press firmly against the electrode and pretension it.

[0015] The electrodes are preferably made of metal. The electrodes can be provided with a coating, especially a metal or metal alloy coating, especially on the outside. The melting temperature of the metal of the coating is preferably lower than the melting temperature of the material that constitutes the electrode. Silver or a silver alloy is suitable as the metal coating. However, other metals can also be used, especially metals with a low tendency to oxidize and / or high electrical and / or thermal conductivity.

[0016] A unique advantage of the structure of the present invention is the thermal isolation between the electrode and the hose. Furthermore, even if the electrode heats up with extended use, it will not melt the external hose as a result of thermal conduction. Therefore, compared to conventional probes, the plasma probe of the present invention has a cooler distal end, allowing for a longer lifespan. Furthermore, the impact of heat generated by the probe on tissue is reduced. Furthermore, at the two-dimensional connection between the proximal end of the electrode and the plastic sheath of the conductor, slight melting of the plastic sheath occurs, thus establishing a rigid material bond connection between the electrode and the conductor or its plastic sheath during use.

[0017] Furthermore, the concept according to the invention allows for precise radial and axial orientation of the electrodes: even if the outside of the hose undergoes short-term deformations, the positioning of the electrodes is not affected thereby.

[0018] The lumen enclosed by the hose can be separated into two or more sublumens extending parallel to one another. The separation can extend over the entire length of the hose or only over a portion of its length. The separation into sublumens can be achieved by a wall extending radially or obliquely to the radial direction connecting the hose to the plastic sheath. The wall can provide support and keep the conductors centered inside the hose. Thus, the hose, along with the plastic sheath for the conductors and at least one connecting wall between the hose and the plastic sheath, can be manufactured in a single process, for example, by plastic extrusion. Therefore, it is preferable to use only one plastic material. However, it is also possible to use different plastics for the hose and the plastic sheath and to manufacture the probe by coextrusion. Furthermore, the plastic sheath and the hose can be provided as separate elements of the same or different plastic materials. The conductors with their plastic sheaths can be movably positioned within the hose, for example, axially and / or radially.

[0019] In all of these embodiments, there is no metallic connection between the conductor and the electrode, on the one hand, or between the conductor and the hose, on the other hand. If a material connection exists between the plastic sheath and the hose, this connection preferably does not include metallic or other good heat-conducting elements. In this way, thermal conductivity between the electrode and the hose is minimized. Furthermore, the distal end of the hose can be provided with an electrically insulating, heat-resistant sleeve, for example made of ceramic, to prevent direct contact between the generated plasma flow and the plastic hose.

[0020] Preferably, the electrode, retained only at its proximal end, extends distally away from the conductor in a cantilevered manner without protruding from the lumen of the hose, thereby avoiding direct contact between the electrode and the living tissue. However, it is also possible to position the electrode so that it protrudes from the hose, whereby in this case it is preferable to position the insulator body at the distal end of the electrode.

[0021] Further features and characteristics of the plasma probe according to the present invention can be seen from the drawings or the following description. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of a plasma probe according to the invention connected to a supply device. [Figure 2] FIG. 2 is a schematic perspective view of the distal end of the plasma probe. [Figure 3] FIG. 3 is a front view of the plasma probe according to FIG. [Figure 4] FIG. 4 is a view of the plasma probe according to FIG. 3 taken along the dashed line IV-IV shown in FIG. [Figure 5] FIG. 5 is a longitudinal cutaway view of a modified plasma probe according to the invention. [Figure 6] FIG. 6 is a longitudinal cutaway view of a further variant of the plasma probe according to the invention. [Figure 7] FIG. 7 is a longitudinal cutaway view of a further variant of the plasma probe according to the invention. [Figure 8] FIG. 8 is a longitudinal cutaway view of a further modification of a plasma probe according to the invention. [Figure 9] FIG. 9 is a partial cutaway side view of a plasma probe having an insulator body. [Figure 10] FIG. 10 is a front view of a modified plasma probe according to the present invention. [Figure 11] FIG. 11 is a front view of a further modification of a plasma probe according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] 1 shows a plasma probe 11 connected to a supply device 12. The device 12 provides the operating medium and power necessary for the operation of the plasma probe 11. For this purpose, the device 12 comprises a high-frequency generator 13 and a gas source 14. The gas source 14 comprises, for example, a pressure regulator and a valve by which a gas flow, for example an argon flow, taken from a gas cylinder can be delivered to the plasma probe 11 in a controlled manner.

[0024] The plasma probe 11 comprises a hose 15 extending from a proximal end 16 to a distal end 17. A face 18 of the distal end 17 of the hose 15 surrounds a plasma outlet 19 through which the plasma jet emerges during operation. The end portions are always referred to by the terms end, distal end, and proximal end.

[0025] Furthermore, an electrode 20 is arranged at the plasma outlet 19, which is electrically connected to the RF generator 13. For this purpose, for example, a conductor 21 is provided, which extends along the entire length of the hose 15 from the proximal end 16 to the distal end 17, as is evident from FIGS. 3 and 4. The electrode 20 can be made of a heat-resistant material, for example stainless steel, in all embodiments. Furthermore, the electrode 20 can be provided with a coating, in particular a coating whose melting temperature is preferably lower than that of the electrode 20. In particular, the coating can be made of silver or a silver alloy.

[0026] The conductor 21 can also be a monofilament wire, such as a stainless steel wire, or a wire made of another material. The conductor 21 is then provided with a plastic sheath 22, which preferably surrounds the conductor 21 over its entire circumference (360°) along at least a portion of its length. The plastic sheath 22 can thus extend over the entire length of the conductor up to the distal end 23. The distal end 23 of the conductor 21 itself can be exposed, i.e., released from the plastic sheath. The length of the exposed portion can be one millimeter or more. The plastic sheath 22 begins at the distal end 23 and extends proximally for at least several centimeters. However, the plastic sheath 22 can also cover the entire length of the conductor 21.

[0027] In the embodiment shown in Figure 4, the plastic sheath 22 is connected to the hose 15 by at least one, and preferably several, walls 24, 25, 26, as is clear from Figure 3. The walls separate the lumen 27 enclosed by the hose 15 into two or more, in this case three, sub-lumens 28, 29, 30. The walls 24, 25, 26 may extend at an angle relative to the radial direction, as is clear from Figure 3, or may be arranged in other ways. Furthermore, the walls may be configured as flat, as well as curved, as shown.

[0028] As shown in FIG. 4 , the electrode 20 can be realized by a metal tube. The electrode 20 has a central channel or hollow space into which the distal end 23 of the conductor 21 extends. Therefore, the inner diameter of the channel or hollow space is preferably slightly larger than the outer diameter of the conductor 21 so that a loose fit is formed between the channel or hollow space and the conductor 21. In the embodiment according to FIG. 4 , the electrode 20 is configured as a hollow cylinder and is open at the distal end 31. The proximal end 32 of the electrode 20 is pressed against the conductor 21 until the plastic sheath 22 is inserted between the conductor 21 and the plastic sheath 22. As a result, FIG. 4 shows that the plastic sheath 22 is locally released from the conductor 21 and stretches, thereby initially securing the electrode 20 by at least a friction fit. The distal end 23 of the conductor 21 is loosely positioned inside the channel or hollow space of the electrode 20, so that it initially selectively abuts against the electrode 20. The connection between the conductor 21 and the electrode 20 is preferably loose in the axial direction, i.e. no tensile forces are transmitted.

[0029] In all the embodiments described above or below with a sleeve-shaped electrode 20, the electrode 20 can have a surface oriented obliquely relative to its longitudinal direction. For this purpose, the tubular electrode 20 can be cut obliquely relative to the axis of the electrode 20 at its distal end, which corresponds to the distal end of the syringe cannula.

[0030] Regardless of the inclination of the face of electrode 20, the supply line can extend through electrode 20 and protrude beyond the distal end of electrode 20. This can contribute to improved ignition ability.

[0031] The plasma probe 11 described above can be manufactured by providing a first hose 15 having an electrical conductor 21 disposed therein. For example, the hose 15 having the electrical conductor 21 can be manufactured like a cable by plastic extrusion. From the material thus provided, the plasma probe 11 is cut to a desired length, first exposing the electrical conductor 21 at the distal end 23. This removes the material of the plastic sheath 22 and the walls 24-26. At this time, the distal end 23 of the electrical conductor 21 is exposed.

[0032] In the next step, the electrode 20 is now pressed against the exposed distal end 23 of the conductor 21 and into the plastic sheath 22. As can be seen in FIG. 4, the electrode 20 thereby presses the plastic sheath 22 radially outward, thereby clamping the electrode 20 against itself. The electrode 20 is now held by a friction fit. The distal end 23 of the conductor 21 selectively abuts loosely against the inner wall of the electrode 20. Therefore, the electrode 20 is preferably inserted until it is positioned behind the distal surface 18 of the hose 15, i.e., offset proximally relative to this surface 18, as viewed from the outside. The plasma probe 11 is now ready for use.

[0033] For operation, plasma probe 11 is coupled to device 12, with the proximal end of electrical conductor 21 electrically connected to RF generator 13. The proximal end of lumen 27 is coupled to gas source 14. For operation, lumen 27 is supplied with a gas, e.g., argon or another inert gas, so that a distally flowing gas stream is generated within lumen 27. RF generator 13 supplies an RF voltage, typically several hundred volts, to electrode 20 relative to a neutral potential applied to the treated patient by a neutral electrode, not shown.

[0034] A so-called spark is then generated at the electrode 20, which ionizes the released gas, resulting in the creation of a plasma jet. Current then flows from the conductor 21 to the electrode 20 via the contact spot between the distal end 23 and the electrode 20, and from the electrode 20 to the patient via the ionized gas. This current flow can selectively solder or weld the conductor 21 to the electrode 20, thus creating a mechanical connection. Furthermore, the electrode 20 heats up significantly, causing the plastic sheath 22 to melt or fuse in the area covering the electrode 20. This creates a material bond between the sheath 22 and the electrode 20 and / or between the conductor 21 and the electrode 20.

[0035] Modifications to plasma probe 11 can be made without departing from the scope of the present invention. For example, referring to Figure 5, each of walls 24, 25, and 26 can be omitted. Electrical conductor 21 is loosely positioned within lumen 27 along with sheath 22 and can move axially and / or radially within lumen 27.

[0036] Regardless, electrode 20 may be provided with a closed end 33 forming the distal end of electrode 20. In particular, with regard to the connection between electrical conductor 21 and electrode 20, the above explanations apply mutatis mutandis.

[0037] Also, many variations are possible regarding the connection between the electrode 20 and the conductor 21. For example, instead of the sleeve-shaped electrode 20 according to Fig. 4 or Fig. 5, a needle- or rod-shaped electrode 20' can also be used, as shown in Fig. 6. This electrode can also be inserted between the conductor 21 and a plastic sheath 22 and thereby clamped. As in the embodiment described above, the conductor 21 can be a solid wire. However, in this embodiment, and also in the embodiments according to Figs. 3 and 4 described above, a braided wire can be used instead of the solid wire.

[0038] In the plasma probe according to Fig. 6, exposure of the distal end 23 of the conductor 21, i.e. removal of the plastic sheath 22 in this region, can be omitted. While in the embodiments according to Figs. 1 to 4 the conductor 21 or its distal end 23 guides the electrode 20 during insertion into the plastic sheath 22, such guidance is not necessary in the embodiment according to Fig. 6. The electrode 20', which is preferably pointed at its proximal end, can simply pierce the plastic sheath 22 near the conductor 21.

[0039] In all probes according to Figures 3 to 6, the distal end 17 of the hose 15 can also be formed by a heat-resistant sleeve 34, for example made of ceramic. This is shown by way of example in Figure 6 for all other embodiments. The sleeve 34 can be connected to the hose 15 via a tapered seat 35.

[0040] It is not necessary to move the electrode 20 between the conductor 21 and its plastic sheath 22 or to fix the electrode 20 by clamping. FIG. 7 shows an embodiment of a plasma probe 11 for this purpose, in which the electrode 20 is only connected to the distal end 23 of the conductor 21, which is released from the plastic sheath 22. The electrode 20 can be held loss-proof on the distal end 23 of the conductor 21 by radial deformation, e.g., crimping. FIG. 7 illustrates, by way of example only, a plasma probe 11 in which the conductor 21, its plastic sheath 22, and the electrode 20 are not rigidly connected to the hose 15. The construction principle of having an electrode 20 fixed only to the conductor 21 can also be realized in any of the other plasma probes 11 described above. Furthermore, all of the above-mentioned and below-described constructions of the electrode 20, conductor 21, and plastic sheath 22 can also be used in probes in which there is no connection between the hose 15 and the plastic sheath 22. For example, electrical conductor 21 with plastic sheath 22 may be disposed within hose 15 as a single wire cable.

[0041] In any probe in which the conductors 21 and their sheaths 22 are not connected to the hose 15, the sleeve 34 located at the distal end 17 can have three or more inwardly facing noses 36, 37 or another structure that limits the radial mobility of the electrode 20 or the conductors 21. The noses 36, 37 are therefore suitable for adequately centering the electrode 20. If the electrode 20 is mechanically connected to the conductors 21, for example, by radial squeezing as shown in FIG. 7, the plastic sheath 22 can be omitted entirely. This applies to all embodiments.

[0042] FIG. 8 illustrates another variation of the present invention, which can be used with all plasma probes 11 described herein. The electrode 20 consists of a first sleeve 20a located at the distal end 23 of the electrical conductor 21 and inserted into a plastic sheath 22. A second sleeve 20b is located on top of the first sleeve 20a, and the second sleeve 20b is, for example, welded or crimped to the sleeve 20a, or simply friction-fitted onto the sleeve 20a. The two sleeves 20a and 20b are preferably made of different materials or combinations of materials. For example, the hollow cylindrical sleeve 20b can be silver-plated on its outer surface, which concentrates the plasma discharge at the distal end of the hollow cylindrical sleeve 20b and minimizes heat transfer to the sleeve 20b. Conversely, the sleeve 20a can be made of uncoated stainless steel, which has low thermal conductivity, to minimize heat transfer to the plastic sheath 22. Regardless of the material choice, heat transfer into the plastic can be reduced by the distance between the sleeve 20b and the plastic sheath 22.

[0043] The sleeve 20a and the joint between the sleeves 20a, 20b form a thermal barrier between the discharge-stricken part of the electrode 20 and the rest of the plasma probe 11. This increases the durability of the electrode 20 and the plasma probe 11 as a whole, on the one hand due to an increase in the electrode surface, and on the other hand due to a reduction in the heat flow emanating from the electrode 20.

[0044] In all of the embodiments of the plasma probe 11 described above, it was assumed that the electrode 20, 20′ does not protrude beyond the distal surface 18 of the hose 15. However, a plasma probe 11 according to the example of FIG. 9 may also be provided based on any of the embodiments described above. The electrode 20, which may be coupled to the electrical conductor 21 in any of the ways described above, may then protrude distally beyond the surface 18 and support an insulator body 38, for example, made of ceramic or another heat-resistant plastic. The insulator body 38 may thereby be formed into a ball, mushroom, or any other shape and supported by the electrode 20.

[0045] There is a great deal of freedom in terms of the configuration of the hose 15 and the plastic sheath 22. For example, as shown in Figure 10, the walls 24, 25, 26 can be arranged radially. Also, the conductor 21 can first be surrounded by an insulating portion 39 embedded in the plastic sheath 22. Furthermore, the number of walls or other connections between the plastic sheath 22 and the hose 15 can be defined differently from the embodiment described above, as shown in Figure 11. Here, only a single connecting wall 24 is provided between the hose 15 and the plastic sheath 22.

[0046] The plasma probe 11 according to the present invention comprises a hose supporting an electrode 20 at at least its distal end, within which an electrical conductor is disposed. The electrode 20 is either directly fixed to the electrical conductor 21, or a plastic sheath 22 is provided around at least the distal end of the electrical conductor 21, which holds the electrode 20. The electrode 20 can be inserted between the electrical conductor 21 and the plastic sheath 22 and thus secured. After initial use, the plastic sheath 22 can be fused to the electrode 20. However, in either case, the electrical conductor 21 is disposed with a gap within the channel or hollow space of the electrode 20. This prevents heat transfer from the electrode 20 to the electrical conductor 21, even when the electrical conductor 21 and the electrode 20 are in spot-like contact due to the gap between them, thereby limiting heat input to the plasma probe 11. This is beneficial to the lifespan of the plasma probe 11 and simultaneously reduces its external temperature and, therefore, its adhesion to tissue. This reduces the risk of undesired puncture of sensitive or thin tissue layers. Furthermore, the concept according to the present invention allows the probe to maintain its roundness over time. [Explanation of symbols]

[0047] 11 Plasma Probe 12 Equipment 13 RF Generator 14 Gas Source 15 Hose 16 Proximal end of hose 15 17 distal end of hose 15 18 distal surface of hose 15 19 Plasma exhaust port 20, 20' electrode 20a, 20b sleeve 21 Conductors 22 Plastic sheath 23 Distal end of conductor 24~26 Wall 27 Lumen 28-30 sublumens 31 distal end of electrode 20 32 proximal end of electrode 20 33 closed distal end of electrode 20 34 Sleeve 35 Tapered seat section 36, 37 Nose 38 Insulator body

Claims

1. a hose (15) having a proximal end (16) and a distal end (17) with at least one lumen (27) formed therebetween; an electrical conductor (21) disposed within the hose (15) and extending from the proximal end (16) to the distal end (17) of the hose (15), the electrical conductor including a plastic sheath (22); an electrode (20) including an end (32) electrically connected to the electrical conductor (21) and an end (33) extending distally; The electrode (20) is held by the conductor (21) and / or the plastic sheath (22) of the conductor (21); The proximal end (32) of the electrode (20) extends between the conductor (21) and the sheath (22). Plasma probe (11).

2. The lumen (27) is connected to a gas source (14) at the proximal end (16) of the hose (15). The plasma probe of claim 1 .

3. The electrical conductor (21) is connected to a power source (13) at the proximal end (16) of the hose (15). The plasma probe of claim 1 .

4. The lumen (27) is separated into two or more sub-lumens (28, 29) arranged parallel to each other. The plasma probe of claim 1 .

5. The conductor (21) is centrally located inside the hose (15). The plasma probe of claim 1 .

6. The plastic sheath (22) and the conductor (21) disposed therein are not connected to the hose (15). The plasma probe of claim 1 .

7. The plastic sheath (22) is connected to the hose (15) by at least one flexible wall (24) or by a plurality of flexible walls (24, 25, 26). The plasma probe of claim 1 .

8. The conductor (21) is supported within the hose (15) only by the flexible wall (24) or the flexible walls (24, 25, 26). The plasma probe of claim 7.

9. The end (32) of the electrode (20) connected to the conductor (21) or the entire electrode (20) is hollow, and the conductor (21) extends into and / or through the electrode (20). The plasma probe of claim 1 .

10. The electrode (20) includes a coating The plasma probe of claim 1 .

11. The electrode (20) has a central channel or hollow space into which the distal end (23) of the conductor (21) extends, the inner diameter of the central channel or hollow space being greater than the outer diameter of the conductor (21). The plasma probe of claim 1 .

12. The electrode (20) is held on the conductor (21) by plastic deformation. The plasma probe of claim 1 .

13. The distal end (33) of said electrode (20) is provided with an insulator body (38). The plasma probe of claim 1 .

14. A method for assembling an electrode (20) of a plasma probe (11), comprising the steps of: providing a hose (15) having a proximal end (16) and a distal end (17) with a lumen (27) formed therebetween, wherein an electrical conductor (21) including a plastic sheath (22) is disposed within the hose (15) and extends from the proximal end (16) to the distal end (17) of the hose (15); Providing an electrode (20) having at least one hollow end (32); pressing the hollow end (32) of the electrode (20) against the end (23) of the conductor (21); and inserting the hollow end (32) of the electrode (20) into the plastic sheath (22) of the conductor (21). method.

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