INSTRUMENT FOR ELECTROSURGICAL TREATMENT

Description

[0001] The invention relates to an instrument, in particular a probe or endoscopic probe, designed for thermal treatment, for example, electrosurgical treatment of tissue. The instrument or probe can act thermally on the tissue using a solid body or a plasma. The instrument can be designed, for example, for cauterization or plasma coagulation, in particular argon plasma coagulation.

[0002] Such an instrument is known, for example, from DE 198 20 240 A1. The instrument can be guided through the working channel of an endoscope. Following the distal end, the instrument has marking rings that allow a surgeon to determine how far the distal end protrudes from the endoscope.

[0003] US Patent No. 9,155,587 B2 describes an instrument for treating tissue. The areas to be treated can be reached intravascularly with the instrument, for example, within the heart. Tissue areas can be ablated, for example, using an electrolytic fluid.

[0004] Other instruments for removing or treating tissue are known, for example, from US 2004 / 0106937 A1, US 2017 / 0020395 A1, US 2008 / 0009747 A1 and DE 10 2008 004 843 A1.

[0005] When treating tissue thermally, and especially electrosurgically, it's often difficult for the surgeon to estimate the dosage of the treatment—that is, how long the tissue in the application area needs to be thermally treated or what energy needs to be applied per unit area to achieve the desired depth of penetration. The tissue must be treated neither too briefly nor too long to avoid underdosing or overdosing and to achieve the desired effect, especially the desired depth of penetration.

[0006] Based on this, it is an object of the present invention to provide a probe which simplifies dosing, in particular the estimation of the duration of treatment in the application area.

[0007] This object is achieved by a probe having the features of patent claim 1.

[0008] The instrument or probe is configured for the thermal treatment of tissue. The tissue is treated in an application area, in particular using a plasma. Preferably, the instrument or probe is configured for electrosurgical coagulation, in particular argon plasma coagulation.

[0009] The instrument has an instrument body, which, depending on the design of the instrument or probe, can be formed by a rigid tubular body that is inflexible under the forces typically encountered, or by a flexible hose body. The instrument body extends from a proximal end to a distal end. At the proximal end, the instrument body can be connected to a power supply and control unit.

[0010] The instrument has an electrode in the region of the distal end of the instrument body, to which a voltage, in particular a high-frequency alternating voltage, can be applied. The electrode can be connected via an electrical line running in the instrument body to an electrical connector, which is located in particular at the proximal end of the instrument or probe. A supply line of a power and control unit can be connected to the electrical connector in order to apply the voltage to the electrode.

[0011] The electrode can be used to thermally influence the tissue through direct contact (e.g. during cauterization) or indirectly via an electrically conductive medium (e.g. during coagulation).

[0012] In one embodiment, the instrument or probe is configured for plasma coagulation, in particular argon plasma coagulation. A fluid channel can then be formed in the instrument body, which is fluidically connected to an outlet opening in the region of the distal end. The electrode is preferably arranged in the region of the outlet opening within the instrument body. The electrode is surrounded by a fluid, in particular an inert gas, a gas mixture, or an additive added to the inert gas.

[0013] With this instrument configuration, in a preferred application, the fluid exiting the outlet opening, particularly the inert gas, can be ionized by the electrode and converted into an electrically conductive state, for example, by converting it into a plasma. The fluid is directed onto the tissue in the application area. Due to the electrically conductive state of the escaping ionized fluid, energy is transferred to the tissue. To ionize the fluid, particularly the argon gas, a high-frequency alternating voltage is applied to the electrode, which can be provided to the instrument via the supply and control unit. The ionization of the inert gas takes place in the area immediately upstream of the outlet opening.

[0014] In one application, the energy conducted via the electrode is transferred to the tissue in the application area, for example, by contact between the electrode and the tissue. The energy transferred at the electrode is realized via a high-frequency alternating voltage, which can be provided to the instrument via the power supply and control unit.

[0015] In the region of the distal end, at least one color marking is arranged on the instrument body, which has a defined color or a defined hue and / or a defined color saturation and / or a defined brightness, wherein the color can be brown, brown-beige or red, for example. The at least one color marking is arranged so that it is visible from the outside and can, for example, have a colored print and / or a colored insert. Additionally or alternatively, a component of the instrument body can also be manufactured in the selected or defined color and / or at least partially colored or printed, such as, for example, an end piece having the outlet opening. The at least one color marking can preferably be applied to a lateral surface of the instrument body.

[0016] The at least one color marking can comprise at least one symbol and / or at least one character (number and / or letter) and / or at least one geometric figure, such as a logo and / or a barcode. For example, at least one colored ring can serve as the color marking. The color marking, or at least one of the color markings, is preferably formed by a contiguous, completely filled area in the selected or defined color.

[0017] The color of the color marking is chosen to correspond to the color of a treated tissue with the desired dosage and / or depth of treatment. This means that the color marking is used for color comparison with the color of the treated tissue, and the color of the treated tissue is most similar to the color of the color marking when the desired dosage or depth of treatment has been achieved. A surgeon can therefore immediately determine whether the dosage or duration of exposure has been correctly selected by comparing the color between the color marking and a treated tissue, and thus draw conclusions about the depth of treatment achieved. For a typical application, the following applies: if the color of the treated tissue is lighter than the color of the color marking, the treatment was not carried out for a sufficiently long time.If the color of the treated tissue is darker than the color of the color marking, the treatment has been overdosed, especially if the tissue has been treated for too long. If the color of the treated tissue and the color marking are the same, the correct dosage and treatment duration were used, and the desired depth of penetration into the tissue was achieved. In other applications, the color change may also differ from the typical application described. In any case, at least one color marking indicates the color at which the desired dosage or depth of penetration into the tissue was achieved for the respective application.

[0018] The color of the color marking is preferably brown or brown-beige. The color, shade, or other color characteristic can be selected, in particular, depending on the type of treatment and the tissue type to be treated. In one embodiment, the color of the at least one color marking is a RAL color. Depending on the clinical indication and treatment area or tissue type, RAL colors with the RAL numbers 1001, 1005, 1011, 1024, 8001, 8003, 8007, or 8011, for example, can be used for the at least one color marking. It has been shown that these RAL colors very well reproduce the color tones of the tissue treated with the correct dosage, with one of the RAL colors being selected depending on the type of treatment and the tissue type to be treated. Furthermore, the RAL color is precisely defined and can be reproduced very well in the manufacture of probes.

[0019] To allow the surgeon a sufficiently accurate comparison, it is advantageous if the color marking is sufficiently large. The color marking is preferably flat and preferably has a total area of ​​at least 15 mm 2 or at least 20 mm 2 . Additionally or alternatively, the color marking can be at least 2 mm, at least 3 mm, or at least 5 mm long in the direction of extension of the instrument body. It is further preferred if the specified total area of ​​the color marking is formed as a continuous surface and is preferably completely filled with the defined color.

[0020] In a preferred embodiment, the one color marking or at least one of several color markings is present on a lateral surface of the instrument body, in particular in the form of a print. This one color marking can have the form of at least one stripe or ring.

[0021] In a preferred embodiment, the one color marking or at least one of several color markings is present on a lateral surface of the instrument body, in particular in the form of an at least partially circumferential surface, such as a circumferential ring and / or two or more stripes. It is advantageous if this at least one color marking extends in a circumferential direction around the instrument body, at least around 50% of the circumference of the instrument body. Preferably, the at least one color marking extends completely around the circumference of the probe body and has the shape of a closed annular surface.

[0022] Preferably, the instrument body outside the at least one color marking has one or more colors that differ from the color of the at least one color marking and that, in particular, visually contrasts with the tissue. This improves the visibility of the instrument or probe for the surgeon. For example, the instrument body outside or surrounding the at least one color marking can be blue. The color of the instrument body surrounding the at least one color marking is preferably darker than the color of the at least one color marking.

[0023] It is preferred if the at least one color marking does not extend to the distal end of the instrument body, but is arranged at a distance therefrom.

[0024] It is also preferred if the at least one color marking represents a marking that indicates a defined distance or minimum distance from the distal end. This can indicate to the surgeon when the instrument body or the distal end has been pushed far enough out of an endoscope so as not to damage or impair the optics of the endoscope when applying the plasma. For example, the furthest edge of the at least one color marking can indicate a minimum distance from the distal end. Only when the at least one color marking can be completely seen through the optics of an endoscope is the distal end of the instrument body far enough away from the endoscope to carry out a treatment.

[0025] In one embodiment, the instrument body has an end piece that has the outlet opening. The end piece can, for example, be configured to specify the outflow direction of the fluid or plasma. The end piece can be completely or partially designed in the defined color of the color marking, so that the end piece forms at least one of the color markings.

[0026] The at least one color marking or at least one of several color markings can also have a texture and / or surface structure and / or a matte and / or non-reflective surface. This allows the actual fabric structure to be better represented and the comparison between the textured color marking and the color and / or structure of the fabric to be simplified. Furthermore, a rough and / or matte and / or non-reflective surface of the color marking can prevent light reflections. The surface can preferably have a roughness that corresponds to one of the VDI classes 33 - 42 of VDI Guideline 3400 (surface comparison sample measurement). The surface can have a maximum roughness depth Rmax = 18 - 49 µm, in particular Rmax = 25 µm and / or an arithmetic mean roughness Ra = 4.5 - 12.5 µm, in particular Ra = 6.3 µm.

[0027] The above-explained configurations of the at least one color marking can be combined with one another as desired. For example, an end piece of the instrument body can serve as a color marking, or one or more additional colored areas, symbols, characters, or the like can be present on the outer surface of the instrument body. In a preferred embodiment, the at least one color marking is present exclusively on the outside of the outer surface of the instrument body. In this case, the instrument bodies can be used as identical parts in the manufacture of probes, regardless of the type and configuration of the outlet opening. This allows for scaling effects.

[0028] In one embodiment, the instrument body is designed as an instrument tube. The instrument tube is flexible or bendable transversely to its direction of extension under the forces that occur. The instrument tube is preferably designed to be guided through a working channel of an endoscope.

[0029] Advantageous embodiments of the invention will become apparent from the dependent claims, the description, and the drawings. Preferred embodiments of the invention are explained in detail below with reference to the accompanying drawings. They show: Figure 1 a schematic diagram of an endoscope and an instrument designed as a probe, which is guided through the working channel of the endoscope, Figure 2 an end section of the probe Figure 1 , which protrudes from the working channel of the endoscope in a schematic, block diagram-like representation, Figures 3-5and each of an embodiment of differently designed outlet openings of a probe for a plasma or a fluid in a schematic side view, Figure 6a a schematic representation of a modified embodiment of the end section of a probe, Figure 6b a schematic representation of a modified embodiment of the end section with a color marking extending along the end section of a probe, Figures 7-9 schematic diagrams of a color marking of a probe compared to the color of an application area of ​​a treated tissue, Figure 10 a photographic representation of an end section of a probe with a color marking and under several application areas on a tissue with different application dosages of the probe and Figures 11 and 12 each further embodiments of a probe in a schematic partial representation.

[0030] The invention relates to an instrument for the thermal and, for example, electrosurgical treatment of biological tissue 34. In the embodiments illustrated below with reference to the drawings, the instrument is designed as a probe 17, which is preferably configured for use with an endoscope 15.

[0031] In Figure 1The endoscope 15 is illustrated in the manner of a block diagram. The endoscope 15 has an operating unit 16 that can be handled by the surgeon. The probe 17 can be inserted into a working channel 18 of the endoscope 15 at the operating unit 16. The working channel 18 has an opening at an endoscope end 19 opposite the operating unit 16, from which at least a portion of the probe 17 can be guided. Adjacent to the opening of the working channel 18, at the distal endoscope end 19, a light source 20 and an objective lens 21 are arranged. The area in front of the endoscope end 19, and in particular the tissue to be treated, is illuminated via the light source 20. By means of the objective lens 21 and an optical system or camera, an image of the area in front of the endoscope end 19, and in particular of the tissue to be treated, is captured. The camera and / or optical system of the endoscope 15 transmits the images to an eyepiece and / or an external monitor.

[0032] The instrument, designed as a probe 17, has an instrument body 25, which in the exemplary embodiment is designed as an instrument tube 26 that can be bent transversely to its direction of extension under the forces that occur. Since the instrument is a probe 17, the instrument body 25 could also be referred to as a probe body and the instrument tube as a probe tube. The instrument body 25 and, for example, the instrument tube 26 extend from a proximal end 27 to a distal end 28. At the proximal end 27, the instrument tube 26 is connected to a supply and control unit 29.

[0033] In the illustrated embodiments, the instrument and, for example, the probe 17 are configured for plasma coagulation, for example, argon plasma coagulation. Alternatively, the instrument could also be configured for cauterization or for performing another thermal treatment of biological tissue.

[0034] The probe 17 has an electrode 32 in the region of the distal end 28 of the instrument body 25. The electrode 32 can, for example, be configured to be brought into direct contact with the biological tissue 34 to be treated. In the preferred embodiment, the electrode 32 is configured to thermally influence the biological tissue 34 indirectly via an electrically conductive medium.

[0035] A voltage, in particular a high-frequency alternating voltage, can be applied to the electrode 32. The electrode 32 is connected via an electrical line (not shown) running in the instrument body 25 to an electrical connector, which is located in particular at the proximal end of the instrument or probe. An electrical connection to the supply and control unit 29 can be established via the electrical connector in order to apply the voltage to the electrode 32.

[0036] In the design of the probe 17 for plasma coagulation, a fluid channel 30 is formed within the instrument body 25 or the instrument tube 26 ( Figure 2 ). A fluid G, such as an inert gas, for example argon, can be introduced via the supply and control unit 29. The fluid G flows through the fluid channel 30 to an outlet opening 31 in the region of the distal end 28 of the instrument hose 26.

[0037] The electrode 32 is arranged within the instrument tube 26 and adjacent to the outlet opening 31. As explained, the electrode 32 is electrically connectable to the supply and control unit 29, so that a high-frequency alternating voltage can be applied to the electrode 32. By means of the high-frequency alternating voltage, the fluid, for example an inert gas G, can be ionized and a plasma 35 can be formed. As is shown schematically in Figure 2As illustrated, energy is transferred in the direction E of the applied electric field within an application area 33 to a tissue 34 to be treated by means of the plasma and, for example, the argon plasma. Depending on the dosage, for example the amount and / or the temporal course of the high-frequency alternating voltage and / or the duration of exposure to the application area 33, a deep effect in the tissue 34 to be treated is achieved by the energy input by means of the plasma. The dosage of the energy input, in particular the duration of exposure or treatment in the tissue 34 to be treated, is particularly optimal when approximately two-thirds of the desired deep effect is achieved during the treatment. Due to after-effects within approximately 72 hours after the treatment, the deep effect increases by the remaining third.

[0038] Using probe 17, a thermal or electrosurgical treatment and, for example, argon plasma coagulation of the tissue 34 to be treated can be performed. Argon plasma coagulation is contactless. Thus, probe 17 does not touch the tissue 34 in the application area 33.

[0039] In an end section 38 of the instrument body 25 and, for example, of the instrument tube 26 adjacent to its distal end 28, at least one color marking 39 is provided, which has a color with a defined hue and / or a defined color saturation and / or a defined brightness. The hue can be, for example, a brown hue. The color of the color marking 39 corresponds to the color that the treated tissue 34 assumes in the application area 33 when the energy introduced by the selected dosage leads to the desired depth effect in the tissue 34. The color of the treated tissue 34 in the application area 33 is therefore an indicator of the achieved depth effect and the dosage, in particular the energy introduced per unit area.Using the color marking 39, a visual comparison can be made between the color of the color marking and the color of the tissue 34 in the application area 33 after argon plasma coagulation. It can then be determined whether the dosage was selected correctly.

[0040] For example, the color of the color marking 39 is brown or brown-beige. In the exemplary embodiment, the color of at least one color marking 39 is the RAL color number 1011.

[0041] The one color marking 39 or at least one of several color markings 39 has one or more contiguous color areas. A single contiguous color area is sufficient.

[0042] The one color marking 39 or at least one of several color markings 39 can optionally also have a texture and / or surface structure and / or a matte surface. This allows the actual fabric structure to be better represented and simplifies the comparison between the textured color marking 39 and the color and / or structure of the fabric 34. Furthermore, a rough and / or matte surface of the color marking 39 can prevent reflections, thereby simplifying the color comparison.

[0043] If the one color marking 39 or at least one of several color markings 39 has one or more textures, these can be carried out in accordance with VDI 3400 (surface comparison sample measurement), VDI classes 33 - 42 with the maximum roughness depth Rmax = 18 - 49 µm and the arithmetic mean roughness value Ra = 4.5 - 12.5 µm, in particular VDI class 36, Rmax = 25 µm, Ra = 6.3 µm.

[0044] In the exemplary embodiment, at least one color marking 39 is applied in the end section 38 to a lateral surface 40 or circumferential surface of the instrument tube 26, for example, by a printing process. The color marking 39 can, for example, represent an annular surface partially and preferably completely enclosing the lateral surface 40. In the extension direction of the instrument tube 26 or the end section 38, the at least one color marking 39 has a length of at least 2 mm or at least 3 mm. Preferably, the length of the color marking 39 in the extension direction of the end section 38 is no greater than 5 mm or 6 mm or 7 mm or 10 mm.

[0045] Further markings for a surgeon can be provided on the instrument tube 26 and in particular on the outer surface 40, which can be designed in any desired colors and shapes.

[0046] Instead of a ring surface, the at least one color marking 39 can also have any other configuration. The at least one color marking 39 can, for example, comprise at least one symbol and / or at least one character (number or letter) and / or at least one geometric figure. Thus, a company lettering and / or a company logo can also be used as the color marking 39. Figure 6a The printing of a colour marking 39 in the form of symbols is schematically illustrated.

[0047] In the Figure 6bIn the illustrated end section 28 of a further embodiment of the probe 17, at least one of the color markings 39 is applied, for example, printed, to the lateral surface 40 immediately adjacent to the distal end 28. This color marking can be formed entirely or partially by a hollow cylindrical end piece 41. One or more additional annular color markings, which are arranged, for example, at different distances from the distal end 28, can optionally be present.

[0048] In the embodiment of the probe 17 according to the Figures 2 , 3 and 6aIs one color marking 39 or are all color markings 39 arranged at a distance from the distal end 28 of the instrument tube 26? Preferably, the instrument tube 26, apart from the at least one color marking 39, has a color that visually contrasts with the surrounding tissue, so that the instrument tube 26 is easily recognizable during the operation and, for example, during the endoscopic procedure. Due to the distance of the at least one color marking 39 from the distal end 28, the outlet opening 31 can be positioned at the required distance from the application area 33 of the tissue 34.

[0049] By means of one color marking 39 or - if multiple color markings 39 are present - one of the existing color markings 39, a minimum distance d from the distal end 28 of the instrument tube 26 can be marked. For example, an edge of the color marking 39, in particular the edge of the color marking 39 opposite the distal end 28, can be arranged at a point on the end section 38 of the instrument tube 26 that indicates the minimum distance d from the distal end 28. During endoscopy, the surgeon can see whether the probe 17 or its end section 38 has been pushed far enough out of the working channel 18 of the endoscope 15 so as not to damage the endoscope 15 and in particular the optics during treatment of the tissue 34.

[0050] In all embodiments of the instrument or probe 17, the color marking 39 or one of the color markings 39 can be arranged directly adjacent to the distal end of the instrument body 25. Alternatively, the at least one color marking 39 can be spaced apart from the distal end 28. Both variants have their own advantages.

[0051] In the Figures 3-5 , 11 and 12 Different configurations of the instrument body 25 and the instrument tube 26 are illustrated. The embodiment according to Figure 3 corresponds to the Figure 2 illustrated embodiment, in which the fluid G or the plasma is ejected in extension of the end section 38. In contrast, the instrument body 25 and, for example, the instrument hose 26 in the embodiments according to the Figures 4 and 5an end piece 41 which has the outlet opening 31. The direction of the escaping fluid G or the plasma can be varied via the end piece 41. In the embodiment according to Figure 4 The fluid G or plasma exits in all directions essentially at right angles to the direction of extension of the end section 38. In contrast, the outlet opening 31 at the end piece 41 of the Figure 5 designed so that the inert gas G or the plasma is ejected laterally in one direction essentially at right angles to the direction of extension of the end section 38.

[0052] In the Figures 11 and 12Schematically illustrated are embodiments of the probe in which the electrode 32 protrudes from the distal end 28 of the instrument body 25. These probes can be designed without a fluid channel 30. The electrode 32 can be brought into direct contact with the tissue 34 for thermal treatment or can act on the tissue 34 by sparking without an additional medium.

[0053] In the embodiments in which an end piece 41 is present, the end piece 41 can form a colored marking 39. For this purpose, it can be colored in the defined brown color of the colored marking 39 or completely or partially coated. The end piece 41 can be made, for example, of a ceramic material.

[0054] Based on the Figures 7-10The function of the at least one color marking 39 is explained schematically. By positioning the at least one color marking 39 directly adjacent to an application area 33 within which a fabric 34 has already been treated, a color comparison can be carried out. The brightness of the color is in the Figures 7-9 represented schematically by the density of the points.

[0055] In Figure 7 It can be seen that the color of the color marking 39 is darker than the color of the tissue 34 in the application area 33. There is an underdose and the tissue in the application area 33 must be treated further in order to achieve the desired depth effect.

[0056] In contrast, the colour of the fabric 34 in the application area 33 is Figure 9darker than the color of at least one color marking 39, indicating an overdose. The tissue 34 in the application area 33 has been damaged or impaired beyond the desired depth of effect. The surgeon can recognize this and assess the consequences or initiate any necessary measures.

[0057] In Figure 8 schematically illustrates the situation in which the color of the color marking 39 and the color of the treated tissue in the application area 33 approximately match and the surgeon recognizes that the dosage is correct to achieve the desired depth effect in the tissue 34 immediately after the treatment (approximately two-thirds of the depth effect to be achieved taking into account the after-effect).

[0058] The Figures 7-9 The schematically illustrated situations are based on the photographic illustration in Figure 10shown again. On the left of the image, a first application area 33a can be seen, the color of which is darker than the color of the color marking 39. An overdose has occurred. The color in a second application area 33b essentially corresponds to the color of at least one color marking 39. In this second application area 33b, the correct dosage of the applied energy was achieved. In a third application area 33c, which has a significantly lighter color than the color of the color marking 39, the energy input was underdosed. By further treatment of this third application area 33c, the desired dosage or depth of effect can still be achieved.

[0059] The invention relates to an instrument for the thermal treatment of tissue 34, in particular for electrosurgical treatment and especially for argon plasma coagulation. The instrument has an instrument body 25 extending between a proximal end 27 and a distal end 28. In an end section 38 adjacent to the distal end 28, the instrument body 25 has at least one color marking 39 in a defined color. This color corresponds to the color of a treated tissue 34, which results when the dosage of energy input has been correctly selected to achieve a desired depth effect in the tissue 34. The instrument is preferably designed as a probe 17, in particular as an endoscope probe, and has a flexibly bendable instrument body 25, which can be referred to as an instrument tube 26. List of reference symbols:

[0060] 15Endoscope 16Control panel 17Probe 18Working channel 19Distal endoscope end 20Light source 21Lens 25Instrument body 26Instrument hose 27Proximal end of the instrument hose 28Distal end of the instrument hose 29Supply and control unit 30Fluid channel 31Outlet opening 32Electrode 33Application area 33aFirst application area 33bSecond application area 33cThird application area 34Tissue 35Plasma 38End section 39Color marking 40Shell surface 41End piece dMinimum distance ERection of the electric field GFluid

Claims

1. Instrument for thermal treatment of tissue (34) by introducing energy into tissue (34) to be treated in the application area (33), having an instrument body (25) that extends from a proximal end (27) to a distal end (28), having an electrode (32) configured for application of an electric voltage, characterized in that in the area of the distal end (28) at least one color mark (39) is arranged on the instrument body (25) visible from the outside, wherein the color of the color mark (39) is selected such that it corresponds to the visible color of the treated tissue (34) in the application area (33) treated with the desired dosage and / or depth effect, wherein the dosage describes the introduction of energy into the tissue (34) to be treated.

2. Instrument according to claim 1, characterized in that the color in the at least one color mark (39) is brown or brown-beige.

3. Instrument according to claim 1 or 2, characterized in that the color of the at least one color mark (39) is a RAL-color.

4. Instrument according to any of the preceding claims, characterized in that the color mark (39) has a length in extension direction of the instrument body (25) of at least 2 mm or 3 mm.

5. Instrument according to any of the preceding claims, characterized in that the at least one color mark (39) is provided at a shell surface (40) of the instrument body (25) .

6. Instrument according to claim 5, characterized in that at least a section of the at least one color mark (39) indicates a defined minimum distance (d) from the distal end (28).

7. Instrument according to claim 6, characterized in that the edge of the at least one color mark (39) that is furthest away from the distal end (28) indicates the minimum distance (d) from the distal end (28).

8. Instrument according to any of the claims 5-7, characterized in that the at least one color mark (39) extends in a circumferential direction about at least 50% of the circumference of the instrument body (25).

9. Instrument according to claim 8, characterized in that the at least one color mark (39) extends completely around the circumference of the instrument body (25).

10. Instrument according to any of the preceding claims, characterized in that the at least one color mark (39) has a distance to an exit opening (31).

11. Instrument according to any of the preceding claims, characterized in that the at least one color mark (39) is provided on an end piece (41) of the instrument body (25) comprising an exit opening (31).

12. Instrument according to any of the preceding claims, characterized in that the instrument body (25) is configured as instrument hose (26).

13. Instrument according to claim 12, characterized in that the instrument hose (26) is configured to be guided through an operation channel (18) of the endoscope (15).

14. Instrument according to any of the preceding claims, characterized in that the instrument is configured for plasma treatment of tissue (34).

15. Instrument according to any of the preceding claims, characterized in that a fluid channel (30) is provided in the instrument body (25) that is fluidically connected with an exit opening (31) in the area of the distal end (28), whereby the electrode (32) is arranged inside the instrument body (25) adjacent to the exit opening (31).