MEDICAL INSTRUMENT

Description

[0001] The invention relates to a medical instrument for the medical or surgical treatment of a human or animal patient. In particular, the invention relates to such an instrument that contains a light-guiding device configured to conduct light away from a site of action of the instrument or, additionally or alternatively, to conduct light toward a site of action of the instrument.

[0002] EP 2 113 190 discloses an arrangement consisting of a surgical instrument and a trocar through whose working channel the instrument can be pushed. The instrument contains a light-guiding device by means of which light can be absorbed or emitted at the distal end of the instrument. The trocar is provided at its distal end with one or more protective elements that block the working channel and thus prevent fluids from entering the working channel. When moved distally, the instrument can push the protective element aside to obtain a clear view of the instrument's target area.

[0003] EP 3 195 824 A1 proposes an instrument with a channel in which an optical fiber is arranged for longitudinal movement. The optical fiber has a light-emitting surface at its distal end, from which a laser beam can emerge. The channel is provided at its distal end with a wiping element 21, which closes the channel when the fiber is retracted and prevents fine fluid droplets from entering the channel and deposition from the light exit surface of the fiber. As the fiber is advanced, the wiping element wipes the light exit surface, thus cleaning it.

[0004] Further prior art is provided by EP 1 773 223 B1, which illustrates a device for argon plasma coagulation whose gas-conducting channel is provided with closure elements. WO 96 / 01132 A1 discloses an instrument with an elongated shaft, at the end of which a closure element is located. An elongated optical element can be pushed through the hollow shaft, which is designed to view an area lying in front of the tip of the instrument. The optical element can be moved axially and can be pushed out of or retracted into a distal opening in the instrument. Flexible wings are used to close the opening; in the relaxed state, they rest against one another and can be pushed apart by the optical rod-shaped element.

[0005] There are applications in which the light guide device or another optical element of an instrument should or must be mounted immobile so that it cannot be moved out of a contamination area.

[0006] This leads to the problem underlying the invention, which is to create a way of keeping an optical element of an instrument as clean as possible during use.

[0007] This object is achieved with the instrument according to claim 1: The instrument according to the invention comprises an instrument body in which at least one channel is formed, which has a distal end and a proximal end. Alternatively, such a channel can also be formed "on" the instrument, by being formed in a separate element that is connected to the body of the instrument, e.g., by one or more clamps (e.g., spring clips). The following description applies to both embodiments.

[0008] The channel can extend, in particular, from the distal end of the instrument to its proximal end, at which a connection device can be formed to connect the proximal end of the instrument and, with it, also the channel to a fluid source. The fluid source can, in particular, be configured to supply a gaseous fluid, such as air, a pure gas, for example nitrogen, argon, carbon dioxide or another desired gas, or a mixture of one or more gases. The fluid source can further be configured to supply the gaseous fluid at a predetermined pressure in order to establish a predetermined gas pressure and / or a predetermined gas flow in the channel. The instrument body can have a plurality of channels to deliver or receive fluids at the distal end of the instrument. In particular, the instrument can have one or more gas delivery channels and / or one or more suction channels.

[0009] The at least one channel has a fluid outlet opening at its distal end. In the instrument according to the invention, this fluid outlet opening is simultaneously a light transmission opening through which light can enter and / or exit. This light transmission opening preferably faces an active site of the instrument, in which, for example, an electrode held on the instrument can be arranged. Multiple electrodes can also be provided. One or more such electrodes can be arranged stationary or movable on the instrument. The at least one electrode can also be connected to an electrical source, for example a high-frequency voltage source, in order to act on biological tissue by means of current. In particular, the electrical source is designed to provide a voltage and a current that are large enough to generate a spark at the electrode.For example, the electrode is a cutting electrode, the voltage is a cutting voltage, and the current flowing from the electrode to the tissue is a cutting current. The resulting spark emits light, which shines through the light transmission opening into the canal.

[0010] Furthermore, an optical element having a light transmission window is arranged in the channel at a distance from the distal end of the channel. The light transmission window, and with it the optical element, is immovably arranged in the channel. For example, the optical element is immovably connected to the body of the instrument. Furthermore, the light transmission window of the optical element is spaced proximally from the light transmission opening formed by the gas outlet opening of the channel.

[0011] A closure device is arranged between the light transmission window and the light transmission opening, said closure device comprising a closure member movable between an open position and a closed position. In its closed position, the closure member is designed to block the channel against the passage of particles and in particular liquid droplets, thus shielding the light transmission window of the optical element from contamination. The closure member is further designed to release the channel in the open position for the passage of both gases and light. In particular, the closure member is not controlled by a movement of the optical element, even if the latter is arranged to be movable in the channel. There is no operative connection between the optical element and the closure device, and in particular its closure member.The optical element and the shutter member preferably do not touch each other.

[0012] Further preferably, the optical element is arranged at a fixed distance from the light exit opening of the channel.

[0013] The optical element can, in particular, comprise a light-guiding device or be formed by a light-guiding device. For example, the optical element can be a single optical fiber or a bundle of optical fibers, wherein the fiber or fibers each have a light transmission window at their respective distal end.

[0014] The light transmission window can be used to shine light onto the tissue to be treated for analytical and / or therapeutic purposes. The light transmission window can also be used to capture light generated during tissue treatment, e.g., light from a spark burning between an electrode and the tissue, and feed it to a light analysis device. The light analysis can, for example, be used to identify the tissue undergoing treatment. Other parameters (e.g., spark stability or similar) can also be recorded. Optical emission spectroscopy (OES), optical coherence tomography (OCT), Raman spectroscopy, photoacoustic analysis, or other optical methods can be used for optical evaluation of the light, e.g., for tissue analysis.

[0015] In various embodiments, the closure member can have one end that is fixedly mounted on the instrument, from which the remaining part of the closure member extends. The mounted end can be connected to the instrument in a fixed or movable manner, e.g., pivotable manner. The remaining part of the closure member is thus movably mounted on the instrument and can thus be moved back and forth between an open position and a closed position. The closure member can be rigid or elastic, stiff or flexible.

[0016] Embodiments are possible that operate with just a single closure member. There are also embodiments with multiple closure members, which, for example, are spread apart from one another in the open position and rest against one another in the closed position. The closure member or closure members can be formed by flexurally elastic lamellae. These can be resiliently biased towards one another in order to define a conical or pyramidal shape in the closed position, with the contact lines being the surface lines of the cone or edges of the pyramid. In the open position, the lamellae can be spread apart from one another. It is advantageous if the lamellae are made of flexurally elastic material for this purpose. Additionally or alternatively, the closure member can be made of an expandable material. The closure member can then, for example, have the shape of a cone or a pyramid with a small opening at its or its tip.To open, the material is stretched accordingly, enlarging the opening at the apex of the cone or pyramid. In all of these designs, the base of the pyramid or cone can correspond to the channel's cross-section.

[0017] Preferably, the closure member is arranged such that it blocks the channel in the rest position, whereby it can be moved into the open position by the pressure and / or flow of the fluid, in particular gas, present in the channel. The closure member can be designed to be pneumatically actuated. The channel can be a purge gas channel, whereby the gas pressure of the purge gas or other gas provided by the fluid source is sufficient to open the closure member.

[0018] Preferably, the light transmission window has a viewing cone that extends through the fluid outlet opening and thus through the light transmission opening. The closure member of the closure device is preferably designed such that it blocks the viewing cone in the closed position but releases it in the open position.

[0019] As described above, the closure device can be controlled by the fluid conveyed through the channel, in particular its pressure or flow rate. The fluid acts directly on the closure member, which is thus self-controlled. However, it is also possible to provide an externally controlled closure device connected to a mechanical actuation device. The mechanical actuation device can be, for example, an electromagnetic actuation device, a pneumatic actuation device, or a manual actuation device. For example, the closure member can be mechanically provided with an actuation button of the instrument in order to be moved back and forth in a controlled manner between the open and closed positions. An electromechanical or pneumatic actuator can also be provided to move the closure member between the open and closed positions.

[0020] What all embodiments have in common is that the passage between the light transmission opening and the light transmission window is released in a controlled and regulated manner by controlling the closure device, either by the gas flow or by other actuating elements or media. The release, i.e. the opening of the closure device, can in particular be restricted to times when light transmission is actually required. In addition, the instrument can be designed to open and close the closure device synchronously with the delivery of fluid, for example purge gas, to the site of action of the instrument. Furthermore, the instrument and / or its feeding device can be designed to begin the gas delivery through the channel before activation of the RF electrode and only end it after the end of activation of the RF electrode.In any case, it can be ensured that the passage between the light transmission window and the light transmission opening is only open when a distal gas flow also leads away from the light transmission window, thus largely eliminating contamination of the light transmission window. If there is no gas flow, the closure device closes the passage from the light transmission opening to the light transmission window, thus preventing contamination of the light transmission window. When the closure device is open, contamination is prevented by the existing gas flow, which carries all contaminating particles or droplets away from the light transmission opening.

[0021] The closure device can have a closure member that is spring-loaded towards its closed position and that can be and is moved into the open position by an actuator or the gas flow itself. Alternatively, the suction device can be configured to actuate the closure device. For this purpose, the instrument can have a suction channel that opens near the distal end of the instrument. An actuator connected to the suction channel is then configured to open and close the closure device depending on whether or not there is negative pressure in the suction channel. The suction channel can be connected to a suction device that is configured to be activated synchronously with a generator that feeds the electrode. Alternatively, the suction device can be configured to be activated before the generator is activated and only deactivated again after the generator is deactivated.In general, it is also possible to ensure that a) the closure device is only open while the electrode is energized or b) the closure device is only open while a distally directed purge gas flow is established in the purge gas channel or c) the closure device is only open while a flow in the proximal direction is established in the cancellation channel.

[0022] Further advantageous details of the invention emerge from the claims, as well as the description and the associated drawings with their figures, which show the following: Figure 1 A power supply device with an instrument connected to it, in an overview view. Figure 2 the distal end of the instrument Figure 1 , in schematic cross-sectional representation, Figures 3a and 3b a schematic and partial representation of the instrument with locking device in closed and open state, Figures 4a to 9bfurther embodiments of the instrument and its locking device in the open and closed positions.

[0023] Figure 1 illustrates an instrument 10 according to the invention, which is connected to a power supply device 11. The device 11 is connected to the instrument 10 via a corresponding line 12 and is configured to supply the instrument 10 with at least one operating medium. For this purpose, the device 11 can have one or more fluid sources 13, one or more electrical generators 14, and / or one or more suction devices 15, which are connected to the line 12 or the instrument 10 via one or more plugs 16. Figure 1illustrates the instrument 10 as a handheld instrument for open surgery. However, the invention also extends to instruments of other designs, e.g., laparoscopically inserted instruments or probes that can be inserted into a patient's body through the working channel of an endoscope, a trocar, or through another access.

[0024] The instrument 10 has a distal end 17 and a proximal end 18, which can be formed by the plug 16 or a portion of its cable 12.

[0025] The distal end 17 of the instrument 10 is illustrated separately in Figure 2. It includes the distal section of an instrument body 19, through which at least one channel 20 extends. The channel 20 is in particular a fluid-carrying, for example gas-carrying, channel, which preferably extends from the distal end 17 through the instrument 10 and its entire line 12 to the proximal end 18 or plug 16, where it is connected to the gas source 13. Optionally, the instrument 10 can have further channels, such as a suction channel 21, which also extends from the distal end 17 of the instrument 10 to its proximal end 18 or plug 16, where it is connected to the suction device 15. Optionally, other channels and / or further channels can be provided to guide liquids and / or gases to or away from the distal end 17 of the instrument 10 and to allow them to enter or exit there.

[0026] The instrument 10 can comprise tools for influencing biological tissue. Such a tool can be, for example, an electrode 22 that is held in or at the distal end 17 of the instrument 10 and terminates there, or that protrudes from a gas transfer opening or terminates shortly before it. The electrode 22 is connected to the generator 14 via an electrical line 24 that extends through the line 12 to the proximal end 18 or the connector 16. However, multiple electrodes or other tools, such as a waterjet tool, a laser tool, or the like, can also be provided.

[0027] The channel 20 has a distal opening, which is both a gas outlet opening and a light transmission opening 25. An optical element 26, for example in the form of a light guide, is preferably arranged immovably in the channel 20, which optical element has a light transmission window 27 at its distal end. The light transmission window 27 can be formed by the end face of the optical element 26, i.e., for example, by the end face of an optical fiber. The light transmission window 27, and with it the optical element 26, is preferably arranged axially immovably in the channel 20. The light transmission window 27 is preferably spaced apart from the light transmission opening 25 in the proximal direction.

[0028] A closure device 28 is arranged between the light transmission window 27 and the light transmission opening 25. This closure device 28 is designed to open or close the passage from the light transmission opening 25 to the light transmission window 27 in a controlled manner. Preferably, the closure device 28 is controlled by the gas flow in the channel 20 or by other media, but under no circumstances by any movement of the optical element 26, which, as mentioned, is preferably arranged in a stationary manner.

[0029] A first embodiment of the closure device 28 is shown in the Figures 3a and 3bThe closure device 28 is formed there by an approximately conical closure member 29 made of tensile-elastic material, which has an expandable opening at its tip 30. The tip 30 faces the light transfer opening 25. The opening at the tip 30 is very narrow or completely closed in the closed state. The tensile elasticity of the material of the closure member 29 is so great that the opening 30 can be expanded by the pressure prevailing in the channel 20 to such an extent that the desired gas flow can escape from the light transfer opening 25 and thus the light path from the light transfer opening 25 to the light transfer window 27 is also cleared. When a gas flow is present, the closure member 29 is in the open position.

[0030] A modified embodiment is illustrated by the Figures 4a and 4b The above description applies with the exception of the following special features:

[0031] The closure device 28 comprises several closure members 29a, 29b, 29c which are flexible and, when their edges are in contact with one another, form a cone. At its tip 30, the lamella-like closure members 29a, 29b, 29c, etc., meet and thus close the passage from the light transmission opening 25 to the light transmission window 27. If, however, the channel 20 is pressurized with gas, the closure members 29a, 29b, 29c, etc., spread apart, as shown in FIG. Figure 4b Thus, the passage through the closure device 28 is open for both gas and light, and the closure members 29a, 29b, etc., are in the open position.

[0032] The closure member 29 has a section that is held stationary on the instrument 10. This section is formed by a circular section of the closure member 29, which forms the base of the cone defined by the closure member 28. This section is fixedly connected to the wall of the channel 20. The remaining parts of the conical closure member 29 can be elastically or flexibly deformed and are thus movable.

[0033] In Figures 5a and 5b A further modified embodiment of the closure device 28 is illustrated, in which the closure member 29 is formed from a foldable, flexible, slack material such as a film tube section. This collapses when no gas is applied to the channel 20 and blocks the channel 20 as an irregularly shaped body. When gas passes through, the closure member 29 unfolds, as shown in Figure 5band thus allows the passage of light and gas between the light transmission window 27 and the light transmission opening 25. Otherwise, the above description applies accordingly.

[0034] In the described embodiments of the Figures 3a to 5b The drawing shows a channel with a round cross-section. However, in these embodiments, the channel 20 can also have cross-sections other than circular, for example, polygonal cross-sections such as triangles, rectangles, hexagons, or curvilinear polygons. Purely as an example, the Figures 6a and 6ba configuration of the channel 20 and the closure device 28 with a rectangular channel cross-section is illustrated. The closure device 28 here comprises a closure member 29 designed as a flap, the outline of which corresponds to the cross-section of the channel 20. The flap-like closure member 29 is connected to the instrument or the wall of the channel 20 by an edge 31. The edge 31 can be firmly anchored and the closure member 29 can be flexible. Alternatively, the edge 31 can be held like a hinge. In the locked position Figure 6aThe closure member 29 blocks the channel 20 and thus the passage between the light transmission window 27 and the light exit opening 25. The closure member 29 can be spring-loaded toward this position. This spring-loaded prestress can be provided by the inherent elasticity of the closure member 29 or by a separate spring element. The closure member 29 can be assigned a stop against which it rests in the locked position (not shown). This is particularly advantageous in embodiments in which the closure member 29 is held at the edge 31 by a hinge. Figure 6b the open position of the closure device 28 is illustrated, in which the closure member 29 is forced from its rest position into the open position by the gas flowing through the channel 20 in the distal direction.

[0035] Figures 7a and 7billustrate a further embodiment of a fluid-operated closure device 28. In this case, the closure device 28 includes a balloon-like hollow closure member 29, which in turn is arranged between the light transmission window 27 and the light transmission opening 25. The balloon-like closure member 29 is in fluid communication with a Venturi opening 32 arranged in the gas path, through which the static pressure of the gas flow becomes effective. If the static pressure decreases due to the velocity of the gas flow in the channel 20, this leads to the collapse of the balloon-like closure member 29, so that, as in Figure 7b shown, the closure member 29 releases the gas path.

[0036] In a preferred embodiment, the balloon-like closure member 29 or an actuator for actuating the closure member 29 is connected to the suction channel 21. This allows the negative pressure of the suction to be used to actuate the closure device 28. For this purpose, a transverse bore can be provided at the level of element 28 to element 21 ( Figure 2 ) are provided. This creates a robust system. In particular, larger pressure differences and thus larger actuating forces can be generated.

[0037] In such an embodiment, the suction device 15 and the purge gas source 13 are preferably synchronized with the RF generator 14. This reduces the sound pressure level, which would otherwise be too high during continuous operation.

[0038] All the above-described embodiments have in common that the closure member 29 of the closure device 28 is pneumatically controlled by the effect of the gas or its flow in the channel 20. However, it is also possible to externally control the closure device 28, as is the case with the Figures 8a and 8bin a simple first example. The instrument 10 has an actuating device 33, which is only schematically illustrated and can be formed, for example, by an operating button on the instrument 10. The actuating device 33 can be provided to activate or deactivate the instrument 10 and thus the connected generator 11. The actuating device 33 can additionally or alternatively also be designed to trigger other activation or switching processes, e.g., to trigger a spectral analysis of the light emanating from the spark of the electrode. At the same time, the actuating device can move the closure member 29 via a suitable gear, here only schematically illustrated by a two-armed lever 34, so that it is in the closed position according to Figure 8a blocks the passage between the light transmission window 27 and the light transmission opening 25 and in the actuating position according to Figure 8breleases.

[0039] The actuation of the locking device 28 can, as shown in the example of Figures 9a and 9b can be seen, also by other actuators, for example by a magnetic actuator 35, with which the closure member 29 in the closed position according Figure 9a in channel 20 and in open position, as Figure 9b shows, can be positioned outside channel 20.

[0040] The inventive instrument 10 according to Figure 1works as follows: For use on a patient, the instrument 10 is brought to the operation site and activated by actuating a suitable switch, for example the actuating device 33. Alternatively, other switching means, such as foot switches or other operating devices, can also be used for activation. The device 11 thus receives a corresponding switching impulse and activates the respectively addressed or present devices, such as the gas source 13, the electrical generator 14 and / or the suction device 15. If the instrument 10 is an electrosurgical instrument, the gas source 13 is typically activated before the generator 14 is activated. As long as the gas source 13 is not activated, i.e. the channel 20 is not supplied with gas, the closure device 28 is closed.As soon as sufficient gas pressure is established in the channel 20 and / or a gas flow is established in the channel 20, the closure device 28 opens, at least if one of the embodiments according to the . Figures 3a to 7b applies.

[0041] After activation of the generator 14, light emanating from the electrode 22 is detected by the optical element 26. The electrode 22 is preferably located within the field of view of the optical element 26, i.e., in the field of view emanating from the light transmission window 27 and extending through the light transmission opening 25. Thus, spark light emanating from the electrode can be detected and forwarded by the optical element 26 to an analysis device, for example, a spectrum analyzer, which can be part of the instrument 11 or can be configured and mounted separately.

[0042] The gas stream advancing through channel 20 and flowing out of light passage opening 25 effectively prevents particles, droplets, or other contaminants from depositing on light passage window 27. However, as soon as the gas flow ceases, for example because it is interrupted, the closure device 28 closes. Even if contamination continues to occur due to turbulence or the like, for example due to the activity of the suction device 25, which suctions liquids or other material from the surgical area via suction channel 21, the light passage window 27 remains sealed off and protected from contamination. This also applies if work continues with the electrode 22 without gas flow through channel 20, thus releasing particles.

[0043] The Figures 8a to 9b The illustrated embodiments of the instrument 10 operate in a similar manner. In the embodiment according to Figures 8a and 8b the closure device 28 is always released when the actuating device 33 is activated. The activation of the actuating device 33 can take place independently of the activation of the device 11 and the generator 14. For example, the channel 20 can be pressurized with gas under low pressure. When the closure device 28 is closed, this can simultaneously block the gas flow and the passage of light. The closure device 28 also blocks the passage of contaminants. As soon as the closure device 28 is opened by means of the actuating device 33, the light path is released. At the same time, the gas flow is released, which prevents the penetration of contaminants. If a gas flow is to be possible even when the closure device 28 is closed, a bypass that is opaque to light can be provided parallel to the closure device 28.

[0044] In the embodiment according to Figures 9a and 9b the closure device 28 is actuated by the magnetic actuator 35 or another suitable electrical actuator. The actuator 35 can be energized synchronously with the energization of the electrode 22 or independently of it. The latter, for example, is used if light from the electrode 22 is only to be recorded occasionally. The device 11 is then designed in conjunction with the instrument 10 si, which, in order to record light from the treatment site, for example, for spectral analysis of the light, the spectrometer and the actuator 35 are activated simultaneously. Thus, the light transmission window 27 is permanently protected from contamination. In the activated state, the gas flow through the channel 20 prevents contamination. When deactivated, the closure device 28 closes and closes the light transmission window 27. This principle applies to all embodiments.

[0045] The invention is not limited to electrosurgical instruments. It can also be applied to laser surgical instruments or cryosurgical instruments. In the case of laser surgery, the optical element 26 can be designed to send a laser beam from the light transmission window 27 through the light transmission opening 25 to the tissue. When activated, the gas flow in the channel 20 also keeps the light transmission window 27 free of contamination. When deactivated, the closure device 28 closes, for example, according to the principles of Figures 8a to 9b .

[0046] The instrument 10 can also be a waterjet surgical instrument or another type of instrument. In addition to or as an alternative to the electrode 22, a water injection channel can then be provided to treat corresponding tissue at the surgical site, preferably in the field of view of the optical element 26. The previous description otherwise applies accordingly.

[0047] An instrument according to the invention for the medical or surgical treatment of a human or animal patient has at least one tool suitable for influencing a patient, for example an electrode 22, which lies in the field of view of an optical element 26. The optical element 26 is arranged in a channel 20 in which a fluid flow directed in the distal direction can be maintained or induced. The light transmission window 27 of the optical element 26 is offset proximally from the distal opening 25 of the channel 22. A closure device 28 is arranged between the light transmission window 27 and the opening 25 of the channel 20, which closure device blocks the passage of substances, in particular the passage of liquid droplets and particles, from the opening 25 to the light transmission window 27 as long as it is in the closed position.When the closure device 28 is open, it clears the fluid path and the light path between the light transmission window 27 and the opening 25. Preferably, the closure device 28 is pneumatically controlled by the liquid or gaseous fluid flowing in the channel 20. This measure reliably eliminates or at least minimizes contamination of the light transmission window 27 during operation of the instrument 10. Reference symbol:

[0048] 10Instrument 11Device 12Line 13Gas source 14Electrical generator 15Suction device 16Connector 17Distal end of instrument 10 18Proximal end of instrument 10 19Instrument body 20Channel 21Suction channel 22Electrode 23Gas transfer opening 24Electrical line 25Distal opening of channel 20, Light transfer opening 26Optical element / optical fiber 27Light transfer window 28Closing device 29Closing element 30Tip of the closing element 29 31Edge of the closing element 29 in Figure 6a, 6b 32Venturi opening 33Actuator 34Lever 35Actuator

Claims

1. An instrument (10) for medical or surgical treatment of a human or animal patient, having an instrument body (19) in or on which at least one channel (20) is formed that comprises a distal end (17) and a proximal end (18), wherein the channel (20) is connectable to a fluid source (13) at its proximal end (18) and comprises an opening (25) at its distal end, having an optical element (26) that comprises at least one light passage window (27) that is immovably arranged in the channel (20), having a closure device (28) that is arranged in the channel (20) between the light passage window (27) and the distal end (17) of the fluid channel (20) and that comprises at least one closure member (29) which is movable between an open position and a closed position, characterized in that the closure member (29) is arranged such that it can be actuated by fluid flowing in the fluid channel (20)2. The instrument according to claim 1, characterized in that the closure member (29) comprises an end fixedly mounted on the instrument (10).

3. The instrument according to anyone of the preceding claims, characterized in that the closure device (28) comprises multiple closure members (29a, 29b) that are respectively pivotably mounted at one end on the instrument (10).

4. The instrument according to anyone of the preceding claims, characterized in that the closure device (28) comprises multiple bending elastic lamellae.

5. The instrument according to anyone of the preceding claims, characterized in that the closure member (29) is an element made of a stretchable material.

6. The instrument according to anyone of the preceding claims, characterized in that the channel (20) can be connected to a gas source (13) as a fluid source.

7. The instrument according to anyone of the preceding claims, characterized in that the instrument (10) comprises at least one additional channel (20) for supply or discharge of fluids.

8. The instrument according to anyone of the preceding claims, characterized in that a sight cone is defined by the light passage window (27) that extends through the opening (25).

9. The instrument according to anyone of the preceding claims, characterized in that the instrument (10) comprises an electrode (11).

10. The instrument according to claim 9, characterized in that the electrode (22) is arranged in or in front of the opening (25).

11. The instrument according to claims 8 and 9, characterized in that the electrode (22) is arranged at least partly within the sight cone.

12. The instrument according to anyone of the preceding claims, characterized in that the closure device (28) is connected to a mechanical actuating device (33).

13. The instrument according to anyone of the preceding claims, characterized in that the closure device (28) is connected to an electromagnetic actuating device (35).

14. The instrument according to anyone of the preceding claims, characterized in that the closure device (28) is connected to a pneumatic Venturi actuating device (32).