Surgical Instrument with Position Sensing Device

Abstract

To provide a surgical working instrument that is inserted in a working channel of an endoscope and is slidably located in the endoscope.SOLUTION: A device (27) for determination of the position of a working instrument (3) relative to an endoscope is configured to determine in an optical manner that a distal end of the working instrument (3) has reached a distal end of a working channel The position determination device (27) comprises a light conductor (28) that is attached to the working instrument (3) and configured to receive light surrounding the working instrument (3) in the vicinity of the distal end (14) of the working instrument (3), where based on the light received by the light conductor (28) the position of the light conductor, and thus the working instrument (3), relative to the endoscope can be determined.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a surgical instrument for insertion into a working channel of an endoscope having a device for determining the relative position of the working instrument with respect to the endoscope. [Background technology]

[0002] A device for coagulating biological tissue, particularly in the gastrointestinal tract, is known from German Patent No. 4139029, in which a connecting cable for connection to an RF voltage source is provided within the working channel of an endoscope. An ionizable gas, such as argon, is supplied through the working channel and exits at the distal end of the working channel. An electrode, which serves to ionize the gas and supply a coagulation current, is provided within the gas flow path prior to its exit from the outlet opening. The ionized gas allows the generation of a spark (electric arc) between the electrode and the tissue surface, and the heat generated thereby eschars the affected tissue to a depth of several millimeters.

[0003] In known argon plasma coagulation (APC) devices, the active electrode is positioned a defined distance from the endoscope tip. This avoids excessive thermal stress on the endoscope tip due to the generated heat. However, APC devices with a movable APC probe as a working instrument are also known. The working instrument is inserted into the working channel of an endoscope and advanced therethrough to a desired working position where the active electrode protrudes slightly beyond the distal end of the endoscope. A certain minimum distance between the electrode and the distal end of the endoscope is important to avoid unacceptable thermal stress and damage to the distal end of the endoscope and its attached components, such as the observation optics or CCD camera, and the illumination device for the area to be treated, due to the heat generated during APC coagulation. For this purpose, a device for detecting the relative position of the electrode with respect to the tip of the endoscope is useful.

[0004] Also, for other endoscopic applications using insertable working instruments with light guides, such as optical emission spectroscopy (OES), video endoscopy, rigid laparoscopes, borescopes, fiberscopes, and other endoscopes for guiding instruments inside the human body, position detection for the working instrument may be useful, for example, to position the light guide at a desired distance from the distal end of the endoscope and to avoid contamination of the light guide with fluid, blood, or tissue particle residue during contact with tissue, such as the mucosa of a hollow organ. Such contamination of the light guide may result in scattering, absorption, or degradation of light transmission, thus affecting the endoscopic treatment session.

[0005] German Patent No. 19731931 discloses an endoscope equipped with a pre-used working tool for argon plasma coagulation, which slides inside the endoscope together with the electrode. To use the working tool for contact and non-contact coagulation and / or cutting, thereby reducing the risk of tissue damage and temporary deformation, a sensor is provided in the distal end area that monitors whether the active electrode of the working tool is located inside or outside the endoscopic catheter. The sensor can be a spring-loaded microswitch contact at the distal end of the working tool, a miniature light barrier with a beam that is blocked in the presence of an active electrode, or a plate, coaxial, or cylindrical capacitor with a dielectric that is affected by the presence of an active electrode. The non-contact mode can be activated only when the active electrode is located inside the endoscopic catheter.

[0006] Position determination requires additional components that must be provided at the distal end of the working implement, connections to the distal end for supplying electrical or optical measurement signals to sensors, and appropriate evaluation of the signals provided by the sensors, the implementation and evaluation efforts of which are extraordinary.

[0007] German Patent No. 102004039202 describes a device for measuring the relative position of a surgical working instrument, where the position determination is performed by measuring the complex resistance between the working instrument and the working channel of an endoscope, or alternatively by a pneumatic or acoustic measurement system. To measure the complex resistance, the endoscope, or at least its working channel, must be configured to be conductive. In the case of acoustic or pneumatic measurements, a measurement signal in the form of a sound signal or a gas balance or alternating pressure must be generated and coupled into the working channel of the endoscope or into the lumen of the working instrument, and then detected by an electromechanical transducer or pressure sensor in the working channel or lumen, respectively. This can be relatively complicated.

[0008] A further need remains to easily determine the position of a working instrument relative to the working channel of an endoscope within which the instrument is inserted. Summary of the Invention [Problem to be solved by the invention]

[0009] Starting from this, it is an object of the present invention to provide a detection device for the relative position of a surgical instrument with respect to the working channel of an endoscope, which is simple in means and requires little effort to implement and evaluate.

[0010] In particular, it is an object of the present invention to provide a surgical instrument for insertion into a working channel of an endoscope, the working instrument being slidably arranged within the working channel and having a device for detection of the relative position of the working instrument with respect to the endoscope, which device allows adjustment of the working position of the working instrument with respect to the endoscope for the respective application by simple means and with little effort for implementation and evaluation, so that thermal damage to the distal end of the endoscope, contamination of the light guide, and / or danger to the patient or user can be avoided or at least greatly reduced. [Means for solving the problem]

[0011] To achieve this object, according to the invention a surgical working instrument is provided having the features of claim 1.

[0012] A surgical working instrument for insertion into the working channel of the endoscope is slidably disposed within the working channel, and a device is provided for determining the relative position of the working instrument with respect to the endoscope, the position determining device including a light guide fixed on the working instrument and configured to receive light surrounding the working instrument proximal to the distal end, and the relative position of the working instrument with respect to the endoscope can be determined by the light received by the light guide.

[0013] The present invention is based on the recognition that a light guide can be contained within and secured to a working instrument, whereby during insertion of the working instrument into the working channel of an endoscope, the light guide is inserted and slid internally along with the working instrument, and the light guide is positioned to receive light directly or indirectly at its distal end, so that the position of the working instrument can be determined by the light. Based on the type, intensity, frequency, presence, and / or absence of the received light, it can be determined whether the working instrument is inserted into the working channel of the endoscope, if applicable, how far it has been inserted, and whether it has reached the desired working position. Because position detection operates contactlessly, no special electrical or mechanical components are required, particularly contact switches at the distal end of the endoscope. Furthermore, no special measurement signals, such as current, voltage, optical, acoustic, or pneumatic signals, need to be specially generated or introduced through the working instrument to enable evaluation of relative position. Furthermore, no modifications to the endoscope are required.

[0014] Instead, the light guide may simply be placed over the work implement so that the position of the light guide as determined by the received light characterizes the position of the work implement.

[0015] Preferably, the light guide may comprise an inexpensive optical fiber, especially a glass fiber or a plastic-based optical fiber, for example a polymer optical fiber.

[0016] The optical fiber can extend from a location near the distal end of the work tool to the proximal end of the work tool and transmit the light received by the light guide to the proximal end of the work tool for evaluation.

[0017] In a preferred embodiment of the invention, the working instrument comprises a tube, in particular a rigid tube, or preferably a flexible hose which may, if required, but not necessarily, be made of an opaque material, and the positioning device includes a light entrance surface which is arranged on the outside of the tube and which is configured to receive light from the side surrounding the distal end of the working instrument, so that at least nearly complete darkening is achieved inside the working channel of the endoscope until the working instrument leaves it, thereby allowing good detectability of the exit of the working instrument from the working channel.

[0018] Basically, axial light detection is also possible as an alternative, but lateral light detection allows for simpler, better adjusted and more accurate position detection.

[0019] In a preferred embodiment, the light guide, e.g., an optical fiber, extends substantially along its longitudinal extension within the inner channel (lumen) of the tube of the working instrument, the light entrance surface being formed by the surface of the light guide that is laterally drawn out from the tube. This realization is simple, and the light guide is housed inside the tube in a protected manner. The light guide can preferably extend freely within the inner channel of the tube or can be attached to at least the inner section of the inner channel.

[0020] In another embodiment, the light guide is mounted substantially on the outside of the tube and extends along its longitudinal extension from the distal end to the proximal end of the tube. The light entrance surface can be formed by a beveled surface (fiber bevel) of the light guide. This is also easy to realize, which makes the mounting of the light guide, e.g., an optical fiber, on the outside of the tube simpler.

[0021] In another embodiment, the light entrance surface is formed by a longitudinal glass rod separate from the light guide. The glass rod, preferably made of silicate glass or acrylic glass, is attached to the outside of the tube and has a specific length greater than the width of the glass rod. The length can be greater than half the protruding length of the distal end of the working tool in the desired working position. The glass rod serves to receive the surrounding light and transmit the received light to the light guide, which is connected to the end of the glass rod facing away from the distal end of the working tool for light reception and transmission.

[0022] Because the glass rod extends longitudinally along the length of the tube, different amounts or intensities of ambient light can be detected depending on how far the glass rod extends beyond the distal end of the endoscope, and therefore how much light is received, allowing the position of the working instrument to be accurately determined.

[0023] In each of the embodiments, the light guide may also be selectively pre-embedded inside or outside the house or inside the hose wall during extrusion of the work implement PTFE hose.

[0024] Independent of the embodiment, the position determination device of the present invention is a separate light receiving element, such as a glass rod, that is separate from the light guide and, if appropriate, does not have lenses, mirrors or other optical elements for redirecting the detected light beam radially or transversely to the longitudinal axis of the working instrument towards the light guide that extends longitudinally along the working instrument. The position determination device can therefore be realized by small, relatively simple and inexpensive means, making it suitable also for working instruments that are intended for single use and that must be discarded after use, such as endoscopic probes.

[0025] The surgical working instrument may additionally comprise an evaluation device, which may be or is connected to a proximal end of the working instrument and is configured to receive and evaluate the light received and guided by the light guide to determine the relative position.

[0026] In an advantageous embodiment, the evaluation device comprises an optical spectrometer unit configured to split the received light into spectral components of light so as to determine the spectrum of the received light, i.e., the intensity of light across a range of optical frequencies or within specific discrete frequencies. For example, the spectrometer unit can be based on an optical refractive prism or an optical diffraction grid. The evaluation unit can additionally comprise an electro-optical converter, a photodiode array, or another suitable device to convert the spectrally split light into respective electrical signals that can be evaluated or analyzed to determine the frequency spectrum of the received optical signal. The frequency spectrum analysis can be performed, for example, based on Fourier analysis. A continuous frequency spectrum can be determined for substantially the entire frequency range of the received light, only at individual frequency bands, or only at predefined discrete frequencies.

[0027] The evaluation device may additionally include a spectral analysis unit configured to compare the determined light intensity across a range of optical frequencies or at specific discrete frequencies with stored intensity values ​​of a reference spectrum and, based on the comparison, classify or identify the light received by the light guide. In particular, a reference spectrum of the endoscope's illumination light, e.g., a cold light source, may be pre-stored for use during evaluation by the spectral analysis unit. Also, at least one general reference spectrum of ambient light in a treatment room where the endoscope is used with surgical instruments may be pre-defined and stored. Additionally, it is possible to detect actual ambient light in a treatment room during startup, calibration, or maintenance of a surgical device, convert it into a relevant reference spectrum, and store this reference spectrum for subsequent analysis by the evaluation device. In either case, the intensity conditions in different characteristic frequency ranges, bands, or lines of the light received by the light guide may be determined by comparing them with the pre-defined and stored reference spectrum.

[0028] The spectral analysis unit may be configured to distinguish between ambient light in a treatment room, which is detected when a surgical working instrument is positioned outside the endoscope, at least nearly complete darkness, which is detected when a surgical working instrument is inserted into the working channel of the endoscope but the distal end of the working instrument has not yet protruded from the working channel of the endoscope, and therapeutic or surgical light from an endoscope, which is detected when the distal end protrudes from the working channel of the endoscope to the area to be treated inside the patient's body, thereby causing the light entrance surface and light guide to detect therapeutic or surgical light provided by the endoscope.

[0029] The spectral analysis unit can thus be configured to distinguish between multiple light sources, in particular the cold light source of the endoscope, ambient light, and, if necessary, light emitted from the plasma during coagulation. While ambient light has a wavelength in the visible range, i.e., approximately 400 nm to 800 nm, the working light of the cold light source of the endoscope generally has a characteristic spectrum in the range of 400 nm to 700 nm, while the light emitted from the plasma exhibits characteristic spectral components between 200 nm and 400 nm, but also components in the visible frequency range. The different characteristic spectral progressions, components, or lines allow the spectral analysis unit to reliably distinguish the types of light detected.

[0030] The evaluation device may also comprise a detector unit configured to detect, during insertion of the working instrument into the working channel of the endoscope, when the light entrance surface of the positioning device is exposed to the environment of the treatment room, when it enters the proximal end of the working channel from the environment of the working room, or when it exits the working channel into the body region to be treated, and based on this recognition generate respective position detection signals, which may then be transmitted to a higher-level controller of the surgical working instrument and / or endoscope for further use.

[0031] In a particularly preferred embodiment with a very low complexity, the evaluation device includes a detector device configured to detect whether light with a minimum intensity is received by the light guide and, based thereon, generate a position detection signal that can characterize whether the distal end of the working instrument is located outside or inside the working channel of the endoscope. For this purpose, the evaluation device can include means for converting the received light signal into an electrical signal, such as a photodiode, and a detector unit (light / dark detector) that can compare the intensity of the electrical signal with, for example, a predetermined threshold value to determine whether the signal characterizes light or dark. A change from light to dark or vice versa can be detected. This allows a higher-level control or a user, based on knowledge of the actual operating progress, to determine whether the working instrument is in the treatment room environment, in the working channel of the endoscope, or in the desired working position. The use of a light / dark sensor can very easily automate specific functions of the working instrument, for example, to start a small flow of inert gas (e.g., argon) inside the endoscope during insertion of the working instrument into the endoscope for the purpose of maintaining cleanliness or blocking RF signals until the instrument is correctly positioned. This does not require spectral analysis or more precise location determination.

[0032] In a particularly advantageous embodiment of the invention, the evaluation device based on a light / dark sensor can be integrated into an integral connector, plug or socket arranged at the proximal end of the working instrument and provided for connection to an external control device, and can output an electrical signal directly to the control device which can be used for automatic control. This embodiment is particularly suitable for single-use probes, since the evaluation device can be realized very cheaply and can be disposed of together with the working instrument after a single use.

[0033] If the evaluation device is configured more complexly and comprises a spectrometer unit and a spectral analysis unit, it can also be implemented in a processor-based manner. Some functional components of the evaluation device, for example the detector unit, can be located in a connector of the surgical working instrument that serves as an interface between the surgical working instrument and a higher-level control device, while other functional components, for example related to the storage and evaluation of data or signals, can be integrated in an external control device.

[0034] In either case, an additional control device for the working instrument and / or endoscope can be provided, which is connected or can be connected to the evaluation device and is configured to automatically initiate countermeasures based on the position detection signal (in the simplest case, a light / dark sensor signal) transmitted from the detector unit. For example, upon receiving a first position detection signal indicating the beginning of insertion of the working instrument into the endoscope, the control device can, if desired or necessary, release the supply of inert gas, e.g., argon, to the working instrument to keep it clean. In addition, in this state, a pre-start can be performed, during which the surgical device is parameterized for the subsequent treatment. For example, the required RF voltage and coagulation current can be pre-selected, and the endoscope's treatment or surgical lighting can be turned on during use for coagulation. Preferably, a start-up lock is provided to prevent undesired ignition of a plasma discharge for ionizing the gas jet, and therefore undesired electrical arcs, until the surgical working instrument is positioned relative to the endoscope in the desired working position. Thus, pre-startup of an electrical arc can be avoided when the end of the endoscope is directly adjacent to the tissue surface to be treated, or when the electrodes of the working instrument are still within the working channel of the endoscope or only slightly protruding therefrom. This is because further components, such as the endoscope body and the observation and illumination devices, may be damaged by the heat generated thereby.

[0035] If the control device receives from the detector unit another positioning device indicating that, for example, the distal end of the working instrument with the electrode has reached the desired working position, i.e. the desired distance to the distal end of the endoscope for treatment, the control device can automatically cancel the activation lock and then effect the application of the required RF voltage on the electrode and the supply of the required coagulation current, the supply of inert gas with the required pressure if this has not already happened, control of the fluid flow or other control of the operation of the working instrument and / or endoscope.

[0036] In a preferred application, the surgical working instrument is an argon plasma coagulation (APC) probe for RF coagulation of biological tissue through a flexible endoscope, so that the probe comprises a tube in the form of a flexible hose or a non-conductive material, for example polytetrafluoroethylene (PTFE), through which an inert gas, in particular argon, can be supplied, and also comprises an electrode arranged on the distal end of the tube, to which an RF coagulation current for ionization of the gas can be supplied via a connecting conductor extending into the inner channel of the tube.

[0037] The surgical working instrument may also be configured for other purposes, such as diagnostic endoscopic purposes for videoscopes, endoscopes, gastroscopes, bronchoscopes, colonoscopes, hysteroscopes, cystoscopes, arthroscopes, cardiac catheters, borescopes, fiberscopes, laparoscopes, etc., as well as for hyperthermia applications, and the positioning device allows the head on the distal end of the working instrument to be positioned at a desired relative position to the endoscope at all times during the treatment, operation, or session.

[0038] A display device may also be provided, configured to optically, acoustically, tactilely or otherwise display the position detection signals output by the detector unit to a user to indicate the respective positions of the working instruments, and the user may then manually take the necessary actions to control the operation of the working instruments or endoscope.

[0039] The present invention allows for a simple determination of the relative position of a surgical working instrument with respect to an endoscope with minimal implementation and evaluation effort, for example, to avoid damage to the endoscope during coagulation, to accommodate permitted thermal stresses on the distal end of the probe and endoscope, and / or to avoid contact with the tissue being treated and consequent contamination of the optical fiber. Due to the light conduction of the light guide and the relatively fast evaluation, only short delay times occur. In particular, when using a light-dark detector installed in the connector, inexpensive components are used that are particularly suitable for single-use probes. Contact switches, light barriers, other means for specifically supplying the measurement signal, and shunt resistors are not required in the measurement circuit.

[0040] Further preferred details of embodiments of the invention are evident from the dependent claims, the drawings and the corresponding description. The invention will be explained in more detail on the basis of the figures which show exemplary but non-limiting embodiments of the invention, the same reference numerals being used in all figures to characterize the same elements. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a highly schematic perspective view of a medical device having an endoscope and a working instrument inserted therein in accordance with the present invention; [Figure 2] 2 is an isolated and highly schematic perspective view of the work implement of FIG. 1; FIG. [Figure 3] FIG. 3 is a simplified longitudinal cross-sectional view of the working implement of FIGS. 1 and 2. [Figure 4a] FIG. 4 is a simplified block diagram of an embodiment of an evaluation device for the work implement of FIGS. 1 to 3. [Figure 4b] FIG. 4 is another simplified block diagram of an embodiment of an evaluation device for the work implement of FIGS. 1 to 3. [Figure 5a] 1 is a simplified principle diagram of an endoscope and a working instrument in their relative positions with respect to one another for functional explanation. [Figure 5b] 1A-1C are simplified principle diagrams of an endoscope and a working instrument in different relative positions with respect to each other for functional explanation. [Figure 5c] 1A-1C are simplified principle diagrams of an endoscope and a working instrument in different relative positions with respect to each other for functional explanation. [Figure 6] 1 is a highly schematic longitudinal cross-sectional view of another embodiment of a working implement according to the invention; [Figure 7a] 1 is a highly simplified longitudinal cross-sectional view of another embodiment of a working instrument according to the present invention in position relative to an endoscope; [Figure 7b] 10A-10C are other highly simplified longitudinal cross-sectional views of another embodiment of a working instrument according to the invention, in a different relative position with respect to an endoscope; DETAILED DESCRIPTION OF THE INVENTION

[0042] FIG. 1 is a highly schematic diagram of an endoscopic system 1 according to an embodiment of the present invention, including a flexible endoscope 2, a working instrument 3 inserted into the endoscope 2, and a control device 4. While the endoscopic system 1 is provided in this example for performing argon plasma coagulation (APC) to stop bleeding from lesions in the gastrointestinal tract, among other things, the present invention may also be used in other medical endoscopic systems. For example, while a flexible endoscope 2 is shown here, a rigid endoscope 2 may also be used in other applications. The endoscopic system 1 of the present invention may also be used for several other treatments or procedures, such as desiccating tissue surfaces, eradicating polypectomy remnants, escharging tumors, or thermal tissue marking.

[0043] Here, endoscope 2 comprises a longitudinal, bendable tube or flexible hose 6 of a suitable biocompatible, flexible material suitable for use inside a patient's body, in particular a polymeric material such as, for example, polytetrafluoroethylene (PTFE). Hose 6 defines a working channel 7 through which a working instrument can be inserted. Here, for example, a surgical working instrument 3 is slidably located within working channel 7 of endoscope 1, thereby projecting outward from working channel 7 at a distal end 8 of endoscope 2 configured for insertion into a patient's body. Additionally, at distal end 8 an optional additional working channel 9 leads out which can be used for other working instruments as needed.

[0044] Also, a lens or viewing device 11 is located at the distal end 8 of the endoscope 2, which may be equipped with a CCD camera or may be connected via a glass fiber bundle to an ocular device not shown here.

[0045] In addition, the endoscope 2 comprises an illumination device 12 with a light emitter that projects outward on the distal end 8 of the endoscope 1 and is connected via an optical fiber to a light source, preferably a cold light source, in order to receive high-intensity light in the visible spectral range and, during use, direct this light towards a treatment or surgical area (not shown) inside the patient. Observation of the treatment or surgical area is thereby made possible by an observation device 11, including the capture of pictures by a CCD camera, while the generation of heat, as with conventional light sources, is avoided by the cold light.

[0046] The working instrument 3 may be inserted into the proximal end 13 of the endoscope 2 so as to exit the distal end 8 of the working channel 7, as shown in Figure 1. In this position, the distal end 14 of the working instrument 3 is located within the field of view of the viewing device 11 of the endoscope 2, illuminated by the illumination device 12.

[0047] The proximal end 16 of the working instrument 3 is connected to the control unit 4 by a connector or plug 15. The connector 15 comprises a gas supply line 17, via which the working instrument 3 is in fluid communication with a gas supply device 18 of the control unit 4. The gas supply device 18 is connected to a gas bottle containing a gas stock, e.g., argon, and is configured to supply the gas, e.g., argon, to the working instrument 3 at a predetermined pressure appropriate for the respective treatment.

[0048] The connector 15 also includes an electrical connection conductor 19, through which the working tool 3 is conductively connected to a radio frequency (RF) generator device 21 of the control device 4, from which it receives the RF voltage required to ignite a plasma discharge for ionizing an inert gas, e.g., argon, for supplying a coagulation current to the tissue. For this purpose, an electrode 22 is provided on the distal end 14 of the working tool 3, connected to the connection conductor 19. Here, the electrode 22 is shown as a pin-shaped or tubular ignition electrode, but it can have any shape, for example, the shape of an ignition plate. The electrode 22 can also be arranged on a lug piece or head piece of the working tool (not shown), which can be made, for example, of ceramic to withstand the heat generated by the ignited plasma discharge during use.

[0049] The surgical working instrument 3 is shown in an isolated, simplified perspective view in FIG. 2 and in a schematic longitudinal section in FIG. 3. As shown, the working instrument 3, which may also be referred to as a probe, comprises a tube 23, here configured as a flexible hose and made of a suitable biocompatible material suitable for the application, in particular PTFE. In principle, a rigid tube 23 may also be used in a rigid endoscope. The tube 23 comprises a wall 24 defining a substantially cylindrical inner channel 26, which may also be referred to as a lumen, through which a gas, for example argon, is supplied to the distal end 14 of the working instrument 3. A connecting conductor 19 is also located within the inner channel 26, which extends from the proximal end 16 of the working instrument 3 to the distal end 14 of the working instrument 3 and is connected to an electrode 22 at the distal end.

[0050] During argon plasma coagulation, it is important to properly position the electrode 22 of the working instrument 3 relative to the endoscope 2 during use. In particular, the electrode 22 must be positioned at a minimum distance from the distal end 8 of the endoscope 2 so that the heat generated by the ionized gas acting as a conductor for the coagulation current after ignition of the plasma discharge does not affect the endoscope 2. For example, the working instrument 3 can be configured for single use, thereby being relatively inexpensive to manufacture and discarded after a single endoscopic treatment or surgery. In contrast, endoscopes with their components are relatively expensive and are configured for multiple uses. For this reason, components located at the distal end 8 of the endoscope 2, particularly the observation device 11 and illumination device 12, must be protected from damage caused by heat generated during use. For this reason, a minimum distance of at least approximately 10 mm between the APC probe tip bearing the electrode 22 and the distal end 14 of the endoscope is required for APC probes 3 with an outer diameter of approximately 2 to 5 mm.

[0051] However, on the other hand, the electrode 22 must also not protrude too far from the working channel 7 of the endoscope 2 so that it is positioned within the illumination field of the illumination device 12 and the field of view of the observation device 11 during use and so that undesired contact of the tissue surface to be treated by the electrode 22 is avoided, with the respective risk of damage.

[0052] Additionally, in other applications, proper relative positioning of the probe tip with respect to the endoscope must be ensured, for example, to enable an efficient endoscopic treatment or session, or to avoid undesired contact between the optics or instruments at the probe tip and tissue.

[0053] A positioning device 27 is provided to enable desired relative positioning of the working instrument 3 with respect to the endoscope 2 and to monitor the positional status of the active electrode 22. Referring again to Figures 2 and 3, the positioning device 27 comprises a light guide 28 attached to the working instrument 3 and configured to receive light surrounding the working instrument 3 near the distal end 14 thereof, such that the relative position of the working instrument 3 with respect to the endoscope 2 can be determined by the light received by the light guide 28.

[0054] The light guide 28 is fixedly attached to the working instrument 3 so that it can be inserted and slid into the working channel 7 of the endoscope 1 along with the working instrument 3. The light guide thereby extends from a position near the distal end 14 of the working instrument 3 to the proximal end 16, and can guide light received from the environment to the proximal end of the working instrument 3 for evaluation. The light guide 28 can comprise any optical fiber, for example, an optical fiber, such as a glass fiber or preferably a polymer optical fiber. Relatively inexpensive optical fibers suitable for the present function of position detection are available, for which the highest quality, absolutely lossless light reception and transmission is not required.

[0055] 2 and 3 , the light guide 28, in the illustrated embodiment, is primarily located within the internal channel 26 of the working tool 3. The light guide 28 has a first end 29 attached to the tube 23 of the working tool 3, a second end 31 extending beyond the proximal end 16 of the tube 23, and a light guide central section 32 extending between the first and second ends and located substantially within the internal channel 26. The first end 29 of the light guide 28 extends through the wall 24 of the tube 23 and has a surface 33 oriented radially or laterally outwardly relative to the longitudinal axis of the working tool 3 (not shown). The surface 33 forms a light entrance surface for receiving external light outside the tube 23 and guiding the external light into the light guide 28. The received light is then transmitted through the light guide central section 32 to the second end 31.

[0056] A first end 29 of the light guide 28 is located in the opening 34, is introduced into the flexible tube 23 in a conformal manner, and may additionally be fixed therein, for example by gluing. A face 33 of the light guide 28, which serves as the light entrance end, is preferably substantially flush with the outside of the tube 23. The tube 23 itself is made of an opaque material.

[0057] The second end 31 of the light guide 28 is connected to an evaluation device 36, which can be or is connected to the proximal end 16 of the work implement 3 and is configured to receive and evaluate the light received by the light guide 28 to determine the relative position of the work implement 3. An embodiment of the evaluation device 36 is shown in simplified block diagram form in Figures 4a and 4b.

[0058] 4a, the evaluation device may in a first embodiment comprise a spectrometer unit 37 and an electro-optical converter 38, a signal conditioning unit 39, a spectral analysis unit 41, a storage device 42, a detector unit 43, an output unit 44 and an interface 46. Although the units 37 to 46 are shown here as separate blocks, they merely form functional units, which may consist of one or more physical units or may be distributed among individual units, may be realized in hardware and / or software and may be at least partly embodied by logic which may be implemented in the form of code for execution on a processor not shown here, in order to fulfill the functions of the evaluation device 36 for evaluating the light received by the light guide 28 and determining the relative position of the fixture 3.

[0059] A spectrometer unit 37 is connected to the light guide 28 to receive the light received therefrom and spectrally separate the light into individual frequency components. The spectrometer unit 37 may include, for example, a light-refractive prism or a light-diffractive grid. If necessary, the resulting light may be filtered before being provided to the electro-optical converter 38. The electro-optical converter 38, which may be a photodiode array, converts the spectrally separated light into respective electrical signals for subsequent evaluation and analysis to determine the frequency spectrum of the received optical signal. In the signal conditioning unit 39, the resulting electrical signals may be amplified, filtered from interference signals (e.g., low-pass or band-pass filtered), and otherwise conditioned for further processing.

[0060] The spectral analysis unit 41 is configured to evaluate the electrical signals representing the spectrally separated light components to determine the spectral components or intensities of light within different optical frequency ranges or at defined discrete frequencies, compare them with stored reference spectra, and classify or identify the light received by the light guide based on the comparison. The reference spectra can be predetermined and stored in the memory device 42. Reference spectra for the cold light of the endoscope 3, the ambient light of the working room, and the plasma light resulting from the spark discharge during APC coagulation can be stored. All of these light sources contain characteristic spectra that are significantly distinguished from each other by their respective frequency ranges and intensity values ​​within the light source. For example, the ambient light of the working room contains wavelengths in the 300 to 1100 nm range with a characteristic first intensity distribution, while the work light from the cold light source of the endoscope typically contains a wavelength range of 400 to 700 nm or a subrange within the work light and a characteristic second intensity distribution. The light emitted from the plasma contains a different third intensity distribution with characteristic components in the visible wavelength range and even in the 200 to 400 nm range.

[0061] One or more of the ambient light, the endoscope's cold light, and / or the light emitted from the plasma can also be empirically detected to determine and store an assigned reference spectrum. Alternatively, a representative frequency spectrum obtained from the respective lighting or device manufacturer or a simulated light spectrum can be used as the reference spectrum. In either case, the spectrum analysis unit 41 can determine whether light is received by the light guide 28 and, if so, whether it is the cold light of the illumination device 12 of the endoscope 2, the ambient light of the examination or treatment room, or an optical signal based on a spark discharge, based on a comparison of the intensity values ​​of characteristic discrete frequency lines or frequency ranges within different frequency bands.

[0062] The detector unit 43 is configured to monitor the light types identified by the spectral analysis unit and to recognize, during insertion of the working instrument 3 into the working channel 7 of the endoscope 2, when the light entrance surface, in particular the surface 33 of the light guide 28, is exposed to the environment of the treatment room, when it enters from the environment into the proximal end 13 of the working channel 7, or when it exits the working channel 7 into the body region to be treated. Based on this recognition, the detector unit 43 generates a respective position detection signal that, for example, characterizes the start of insertion of the working instrument 3 into the working channel 7 or indicates that the distal end 14 of the instrument 3 has extended a desired distance beyond the distal end 8 of the endoscope 2, corresponding to the distance between the distal end 14 of the working instrument 3 and the light entrance surface 33.

[0063] An optional output unit 44 may be connected to the detector unit 43 to receive the position detection signal therefrom and convert it into an optical, acoustic or tactile indication signal that is perceptible by a user of the surgical working instrument 3. In this way, the user can know when the working instrument 3 is placed in the desired relative working position with respect to the endoscope 2.

[0064] Alternatively or additionally, the detector unit 43 can be connected to the control device 4 of the endoscope system 1 via an interface 46, and the control device 4 can receive a position detection signal from the detector unit 43 and, based on this, can automatically monitor device countermeasures, for example, which can perform activation locking, pre-activation, parameterization, and / or control of the operation of the working instrument 3 and / or endoscope 2.

[0065] FIG. 4b shows another particularly preferred embodiment of the evaluation device 36', realized in a less complex manner, which can be configured to very simply evaluate the light received by the light guide 28 for source location determination. In particular, the evaluation device 36' allows only the determination of the presence or absence of received light or the distinction between light and dark. As is clear from FIG. 4b, in this case, the evaluation device 36' can comprise means 40 for converting the received light signal into an electrical signal, in particular a photodiode, and a detector unit 43' forming a light / dark detector. The detector unit 43' preferably compares the intensity of the electrical signal, e.g., generated by the photodiode, with a predetermined threshold value to determine whether the light received by the light guide 28 has a minimum intensity. Based on this, the detector unit 43' can generate a position detection signal that characterizes whether the distal end 14 of the working instrument 3 is exposed to light (brightness) or not (darkness), i.e., whether it is located, for example, outside or inside the working channel 7 of the endoscope 2. Thus, light-to-dark or dark-to-light transitions can be detected. The user of the external control device 4 or a higher-level control device can then determine, relatively roughly, the position of the work implement 3 based on the actual operating conditions. Here, distinguishing between different types of light and determining the position more precisely is not necessary. Thus far, the functional units 37-41 for determining and analyzing the frequency spectrum can be omitted here. The interfaces 44, 46, further shown in FIG. 4b, can in the simplest case be connecting lines, plug-ins, or connecting sockets.

[0066] The functioning of the endoscopic system 1 of the present invention as described above will now be explained with further reference to Figures 5a to 5c, in which the progression of the function is shown individually at each relative position of the working instrument 3 with respect to the endoscope 2. The endoscopic system 1 functions as follows.

[0067] When performing argon plasma coagulation, the user of the control device 4 can select the desired mode, thereby activating the components of the endoscope system 1, including the positioning device 27. After evaluation by the evaluation device 36 or 36', the positioning device 27 determines, based on the light received by the light guide 28, that the probe 3 is still located outside the endoscope 2 and exposed to the ambient light of the treatment room, as shown in FIG. 5a. The detector unit 43, for example, determines that the determined frequency spectrum of the received light corresponds to the reference spectrum of the ambient light at least at distinct discrete frequencies, but is significantly different from the reference spectrum of the cold light source of the endoscope 2 and the light signal emitted by the plasma, and then indicates a corresponding position signal via the interface 44 or 46. Alternatively, the light-dark detector unit 43' indicates a signal characterizing the light conditions. Whenever a position signal is mentioned, this also refers to the light-dark signal generated by the light-dark detector device 40 or 43'.

[0068] Subsequently, when the user introduces the working instrument 3 into the proximal end 13 of the endoscope 2, as shown in FIG. 5b, the intensity of the light received by the light guide 28 drops somewhat abruptly as the face 33 of the light guide 28 enters the working channel 7. Inside the working channel 7, absolute darkness prevails. The absence of a received light signal can be quickly and reliably determined by the evaluation unit 36 ​​or 36', which in turn can cause the detector unit 43 or 43' to output a respective darkness signal to the output unit 44 and / or the control device 4. Consequently, the control device 4 can perform a pre-start of the endoscope system 1, including parameterizing the RF generator device 21, switching on the illumination device 12, and pre-adjusting the control valves for the gas supply, if this has not already been done. In some applications, the supply of inert gas can be pre-started as soon as it is recognized that the working instrument 3 has been inserted into the working channel 7, allowing the working instrument 3 to be kept clean during the insertion process.

[0069] As shown in Figure 5c, as soon as the distal tip 14 of the probe 3 exits the distal tip 8 of the endoscope 2 and the surface 33 of the light guide 28 leaves the working channel 7, the surface 33 receives the task light emitted from the illumination device 12 onto the distal tip 8 of the endoscope 2 for illuminating the treatment or surgical area. This light is provided by a suitable cold light source 47, which can be integrated into the control device 4 or an external light source, for example. The evaluation device 36 or 36' of the positioning device 27 receives the light signal via the light guide 28 and recognizes a sudden change between the absence and presence of a light signal. For example, a light-dark detector unit 43' determines the transition from darkness to brightness and again indicates a signal characterizing the brightness state. Alternatively, the spectral analysis unit 41 in the evaluation unit 36 ​​can analyze the frequency spectrum of the received light and determine that the received light is task light, i.e., cold light, from the endoscope 2 by referring to a reference spectrum stored in the memory device 42. The output unit 44 enables the detector unit 43 or 43' to output a respective position detection signal for the user, so that the user can know that the probe tip with the electrode 22 has now reached the desired position and therefore the working instrument 3 should not be advanced any further.

[0070] Alternatively or additionally, the position detection signal can be transmitted to the control device 4 via the interface 46, which can then cancel the activation lock of the electric RF signal and automatically initiate control of the operation of the working tool 3. For example, if not already occurring, the supply of ionizable gas, e.g., argon, to the working tool 3 can be initiated, automatically enabling ignition of a plasma discharge by the electrode 22. Thus, the RF generator device 21 can supply the required RF voltage signal to the electrode 22 via the connecting conductor 19 to ignite the plasma discharge and ionize the gas. The resulting argon plasma is used as a current conductor to transmit a coagulation current to the tissue being treated. The treated area can be captured using an optical component 11, e.g., a CCD camera, and an image signal can be transmitted via an optical fiber 48 to an image processing unit 48 of the control device 4 for display to the user on a display (not shown).

[0071] If the user unintentionally or intentionally retracts the working instrument 3 to the point where the face 33 of the light guide 28 enters the working channel 7, this is determined by the evaluation device 36 or 36' of the positioning device 27. The control device 4 then automatically stops the operation of the working instrument 3 and activates the activation lock to cut off the gas and / or RF voltage supply, thereby interrupting the spark discharge and avoiding damage to the endoscope 2.

[0072] The action of repeatedly sliding the working implement 3 in and out of the working channel 7 may also be specifically performed by the user to identify the exact location of the desired working position of the working implement 3. Thus far, activation or pausing of the activation lock can be delayed as long as the user is performing the adjustment.

[0073] Numerous modifications are possible within the context of the present invention. The evaluation device 36 or 36' can be housed in an equipment unit separate from the work implement 3, for example in the control device 4. Alternatively, parts of the evaluation device 36 or 36', for example parts implemented in hardware, can be located in the connector 15 that forms the interface to the external control device 4, while other parts of the evaluation device 36 or 36', for example parts implemented in firmware or software, can be implemented in the control device 4 or another external device, for example.

[0074] In a particularly preferred embodiment, the evaluation device 36' according to FIG. 4b, having a detector device formed by a photodiode 40 and a light / dark detector unit 43', as outlined by the dashed line in FIG. 3, can be located entirely within the connector 15, which is arranged at the proximal end 16 of the working instrument 3 and serves to connect it to the control device 4. In doing so, a very compact and mainly separate unit consisting of the working instrument 3 and the assigned position-determining device 27 can be provided, which is well suited for use as a single-use probe, since the uncomplicated and relatively inexpensive detector devices 40, 43' can also be disposed of after a single use.

[0075] In another modification, the light-dark detector device of the evaluation device 36' according to Fig. 4b integrated in the connector 15 may comprise only a photodiode 40 or another means for converting received light into an electrical signal. The electrical signal may then be transmitted via an interface 46 to an external control device 4 for threshold filtering and / or evaluation. The functionality of the light-dark detector unit 43' of Fig. 4b may be transferred to the control device 4, thereby further reducing the effort and costs of the evaluation device 36' mounted in the connector 15.

[0076] Further embodiments of the position determination device 27 of the present invention are shown in Figures 6 and 7a, 7b. Insofar as they correspond to the type of configuration and / or function, reference is made to the above description under the same reference signs.

[0077] FIG. 6 shows an embodiment in which the light guide 28 is disposed on the exterior 51 of the wall 24 of the tube 23 of the working tool 3, rather than in the inner channel 26. The light guide 28 includes a beveled surface or fiber bevel 52 serving as a light entry surface to receive ambient light at the distal end 14 of the working tool 3 and guide it within the optical fiber central section 32. The optical fiber central section guides the light further to the proximal end 16 of the working tool 3 for evaluation. The beveled surface 52 is oriented not only longitudinally but also radially or laterally outwardly of the tool 3, preferably toward the distal end 14. The central section 33 of the light guide 28 extends from the beveled surface 52 substantially linearly along the tube 23 at the exterior 51 of the tube and can be attached to the exterior 51, for example, by gluing. Essentially, it is also possible to arrange the light guide 28 substantially flush on the exterior 51 of the tube 23, with the optical fiber already embedded in the working tool 3 during extrusion of the hose 23 of the working tool 3. Regardless of how the light guide 28 is attached to the outside of the wall 24 of the hose 23, the external attachment is simplified compared to an arrangement within the inner channel 26 of the work implement. The function of the positioning device 27 in the embodiment according to Figure 6 corresponds to the function described in connection with Figures 1 to 5 above.

[0078] 7a and 7b show yet another embodiment of a positioning device 27 according to the invention, in which the light entrance surface for receiving light surrounding the working tool 3 is formed by a separate light-receiving element, i.e., in the illustrated example, a longitudinal glass rod 53. The glass rod 53, which can be made of silicate glass or acrylic glass, is arranged on the outside 51 of the tube 23, attached to the tube 23, and / or embedded in the tube 23. In either case, the longitudinal glass rod 53 is longer than its width and includes a length directed along the longitudinal extension of the working tool 3. The length of the glass rod 53 is optional and is preferably longer than half the protruding length of the distal end 14 of the working tool 3 at the desired working position or the distance between the distal end 14 of the working tool 3 and the distal end of the glass rod 53. The outer surface 54 of the glass rod 53, facing radially or laterally outward, serves as the light entrance surface. The face end 56 of the glass rod 53 facing away from the distal end 14 of the working tool 3 is connected to the face end 57 of the light guide 28, so that light received by the glass rod 53 is transmitted to the light guide 28 and through it to the proximal end 16 of the working tool 3.

[0079] The functioning of the working instrument 3 and the positioning device 27 in the embodiment according to Figures 7a and 7b largely corresponds to that of the embodiment described above, but here a more accurate determination of the relative position of the working instrument 3 with respect to the endoscope 2 is possible. For example, Figure 7a shows a desired positioning state of the working instrument 3, in which the distal end 14 of the working instrument 3 protrudes from the working channel 7 to such an extent that the electrode 22 is at the desired distance to the distal end 8 of the endoscope 2. In this case, the glass rod 53 has also slid completely out of the working channel 7, causing a high-intensity optical signal to be received by the light guide 28 and supplied to the positioning device 27. The evaluation device 36 or 36' recognizes the optical signal with the maximum intensity, for example based on the maximum of a number of threshold values, and then generates a position detection signal indicating that the working instrument 3 is currently located in the desired working position.

[0080] 7b illustrates a situation in which the distance of the distal end 14 of the working instrument 3 or the electrode 22 to the distal end 8 of the endoscope 2 is less than the desired distance. This situation may occur, for example, during insertion of the working instrument 3 into the working channel 7 in preparation for APC coagulation or another endoscopic treatment or examination, or during operation, if the user unintentionally retracts the working instrument 3 at least partially into the working channel 7. In this case, the tube 6 of the endoscope 2 covers at least a section of the outer surface 54 of the glass rod 53, so that only a reduced amount of light is received by the glass rod 53 and introduced into the light guide 28. The evaluation device 36 or 36' recognizes the reduced intensity of the received light and can in this case, for example, initiate or maintain an activation lock to prevent damage to the endoscope 2 or its components due to proximity to the electrode 22 in the event of ignition of a plasma discharge.

[0081] A surgical working instrument 3 is disclosed that is inserted into and slidably positioned within a working channel 7 of an endoscope 2. A device 27 for determining the relative position of the working instrument 3 with respect to the endoscope 2 is configured to optically determine when a distal end 8 of the working instrument 3 reaches the distal end 8 of the working channel 7. The position determining device 27 comprises a light guide 28 that is attached to the working instrument 3 and configured to receive light that surrounds the working instrument 3 near the distal end 14 of the working instrument 3, and based on the light received by the light guide 28, the relative position of the light guide 28, and therefore the working instrument 3, with respect to the endoscope 2 can be determined.

Claims

1. A surgical working instrument (3) for insertion into a working channel (7) of an endoscope (2), comprising: a position determining device (27) for determining a relative position of the working instrument (3) with respect to the endoscope (2); The position determination device (27) comprises a light guide (28); the light guide (28) is attached to the working tool (3) and configured to receive light surrounding the working tool (3) near a distal end (14) of the working tool (3); the relative position of the working instrument (3) with respect to the endoscope (2) can be determined based on light received by the light guide (28); The working tool (3) comprises a tube (23), The light guide (28) is attached to the tube (23); The position determination device (27) includes a light entrance surface (33, 52, 54); the light entrance surface (33, 52, 54) is arranged in contact with a side surface of the tube (23) or an exterior of a wall of the tube (23) and configured to receive light surrounding the distal end (14) of the working instrument (3) from the side surface of the tube (23) and guide it to the light guide (28); Surgical work instruments (3).

2. the light guide (28) comprises an optical fiber attached to the working instrument (3), such that the light guide (28) can be inserted and slid within the working channel (7) of the endoscope (2) together with the working instrument (3) during insertion of the working instrument (3); A surgical work instrument (3) according to claim 1.

3. the light guide (28) extends from a location near the distal end (14) of the working instrument (3) to the proximal end (16) of the working instrument (3) and transmits light received by the light guide (28) to the proximal end (16) of the working instrument (3) for evaluation. A surgical work instrument (3) according to claim 1 or 2.

4. The light entrance surface is formed by a surface (33) of the light guide (28) guided from the inside of the tube (23) to a side surface of the tube (23), The light guide (28) extends inside the tube (23) along the longitudinal extension of the tube (23). A surgical work instrument (3) according to any one of claims 1 to 3.

5. the light entrance surface is formed by a beveled surface (52) of the light guide (28); The light guide (28) is attached to the outside of the wall of the tube (23) and extends along the longitudinal extension of the tube (23). A surgical work instrument (3) according to any one of claims 1 to 4.

6. said light entrance surface is formed by the outer surface (54) of a longitudinal glass rod (53) attached to the outside of the wall of said tube (23), whereby the longitudinal extension of said tube (23) is directed in said longitudinal direction of said working tool (3); a face end (56) of the longitudinal glass rod (53) facing away from the distal end (14) of the working tool (3) is connected to the light guide (28); A surgical work instrument (3) according to any one of the preceding claims.

7. an evaluation device (36, 36') connected to a proximal end (13) of the working instrument (3) and configured to receive and evaluate light received by the light guide (28); A surgical work instrument (3) according to any one of the preceding claims.

8. said evaluation device (36) comprising an optical spectrometer unit (37) configured to split the received light into its spectral components; A surgical work instrument (3) according to claim 7.

9. The evaluation device (36) comprises a spectral analysis unit (41), the spectral analysis unit (41) is configured to compare the determined light intensity over a range of optical frequencies or within specific discrete frequencies with a stored reference spectrum and to identify the light received by the light guide (28) based on the comparison. A surgical work instrument (3) according to claim 8.

10. The evaluation device (36) comprises a detector unit (43), the detector unit (43) is configured to determine, during insertion of the working instrument (3) into the working channel (7), when the light entrance surface (33, 52, 54) is exposed to a treatment room environment, when it enters the working channel (7) from the environment, or when it exits the working channel (7) into a body region to be treated, and to generate a corresponding positioning signal based thereon. A surgical work instrument (3) according to any one of claims 7 to 9.

11. said evaluation device (36') comprising a detector device (40, 43'), the detector device (40, 43') is configured to determine whether light having a minimum intensity is received by the light guide (28) and generate a corresponding position determination signal based thereon. A surgical work instrument (3) according to claim 7.

12. said evaluation device (36, 36') being integrated in a connector (15), said connector (15) being disposed at a proximal end (16) of the working instrument (3) and provided for connection to an external control device (4); A surgical work instrument (3) according to claim 10 or 11.

13. the evaluation device (36, 36') can be connected to a control device (4) of the working instrument (3) and / or of the endoscope (2); the control device (4) being configured to automatically effect one or more of the following measures based on the positioning signal: releasing or blocking an electrical signal provided by the working instrument (3) or activating a gas flow in the working instrument (3), or parameterizing and / or controlling the operation of the working instrument (3) and / or the endoscope (2) in a desired working position. A surgical work instrument (3) according to any one of claims 10 to 12.

14. The surgical working instrument (3) is a coagulation probe (3) for RF coagulation of living tissue by means of a flexible endoscope (2), The coagulation probe (3) comprises a tube (23) in the form of a flexible hose made of a non-conductive material, in particular PTFE, through which an inert gas can be supplied; an electrode (22) arranged on the distal end (14) of the tube (23), to which an RF coagulation current can be supplied via a connecting conductor (19) for ionization of the gas; A surgical work instrument (3) according to any one of the preceding claims.

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