Surgical instrument for flexible endoscope

Abstract

Surgical instrument for insertion into an endoscope, preferably a flexible endoscope, having a tubular working shaft which comprises at least one instrument channel having a proximal and a distal end and running along the length of the endoscope for receiving at least one surgical instrument, wherein the surgical instrument is adapted to couple to an electrical waveform generator and to receive an electrical waveform, wherein a distal end of the surgical instrument, which can be stored longitudinally displaceably in the instrument channel, is formed with a cutting tool, where the cutting tool spreads during and / or after exiting the distal end of the instrument channel of the surgical endoscope and wherein the cutting tool is designed as an at least two-armed arrangement of needle electrodes characterized in that a proximal end of a first needle electrode and a proximal end of a second needle electrode and a cutting tool carrier are connected to each other at a connection point of the cutting tool, wherein a spring is formed by the needle electrodes and the connection point, wherein the spring force F of the spring is selected such that, on the one hand, a passive spreading into the untensioned working state is possible during and / or after exiting the instrument channel and, on the other hand, the needle electrodes are provided to be bent in the direction opposite to the resting state of the cutting tool for return into the instrument channel.

Description

[0001] The invention relates to a surgical instrument for insertion into a flexible endoscope according to the preamble of claim 1. The cutting tool arranged at the distal end of the surgical instrument spreads open during and / or after exiting the distal end of the instrument channel of the flexible endoscope. State of the art

[0002] Electrical surgical instruments for resection are known from the state of the art. For resection, high-frequency alternating current is passed through the corresponding instrument through the body part to be treated in order to specifically damage or cut the affected tissue (high-frequency surgery, HF surgery). The biological tissue is cut, coagulated, and / or vaporized. Such resection instruments are used in urology or gynecology to remove diseased or excess tissue by vaporization, for example, in transurethral resection of the prostate in cases of benign prostatic hyperplasia. A high-frequency voltage is applied to the instrument, which acts as an electrode. This voltage is generated using suitable high-frequency generators and fed to the working part of the electrode via appropriate leads. Depending on their design, the electrodes can be operated in a monopolar or bipolar mode.The localized current density of the bipolar electrode causes rapid heating of the tissue surrounding the electrode tip(s), resulting in the vaporization of the tissue fluid or irrigating fluid surrounding the tissue. A thin gas layer (vapor cushion) forms around the electrode tip, which, at sufficiently high voltage (plasma ignition), can be ionized into a constant plasma. The energy of the plasma is transferred, for example, to the cells of the prostate tissue, leading to its localized vaporization.

[0003] Such surgical instruments can be used via an endoscope with a working channel. For example, a urological resectoscope is known from the state of the art. This consists of a rigid tube with multiple channels. Light is directed through one channel into the interior of the body, for example, the bladder. Another channel, an instrument channel, can accommodate surgical instruments, for example, to perform treatments or take tissue samples. The largest channel usually serves as a rinsing and suction device, allowing the organ in question, such as the bladder, to be emptied and filled while observing.

[0004] US Pat. No. 6,231,570 B1 discloses an ablation catheter with multiple internal microcatheters, each microcatheter containing at least one multi-needle electrode. This device is used to ablate a large arrhythmogenic area rather than an arrhythmogenic point in a patient. This catheter is used to treat patients with atrial fibrillation (AFib).

[0005] The document US 2004 / 242 984 A1 discloses a catheter comprising an elongated catheter body having a proximal end, a distal end and at least one lumen extending longitudinally therethrough; an imaging assembly disposed at the distal end of the catheter body and comprising a shaft and at least two spokes movable between a collapsed position, in which each spoke has a distal end attached to the shaft and a free proximal end disposed on the shaft, which in use is the end closer to a user of the catheter, and an expanded position, in which the free proximal end of each spoke extends outwardly from the shaft, and wherein each spoke carries at least one electrode.

[0006] The document EP 3 137 006 B1 discloses a device for providing radiofrequency current to a target tissue site, the device comprising: a cannula having a proximal end and a distal end and a longitudinal axis therebetween, the distal end having a tip, a first electrode configured to conduct and deliver radiofrequency current for heating the target tissue site, the first electrode being disposed within the cannula and having a retracted position within the longitudinal axis of the cannula and an extended position outside the tip of the cannula, an adjustment element disposed at or near the proximal end of the cannula, the adjustment element being configured to engage the first electrode in the retracted position or the extended position, an inflatable anchor element disposed around at least a portion of the longitudinal axis of the cannula and, when inflated,has a larger diameter than the diameter of the cannula and is configured to anchor the cannula tip at or near the target tissue site, and a second electrode disposed within the cannula, the second electrode configured to conduct radiofrequency away from the target tissue site, the cannula having a cooling channel extending longitudinally within the cannula and configured to cool the first and / or second electrodes.

[0007] US 2017 / 035497 A1 relates to the field of tissue mapping and ablation. In particular, US 2017 / 035497 A1 relates to expandable medical devices for identifying and treating local anatomical abnormalities within a body lumen. In particular, this disclosure relates to systems and methods for the focal treatment of overactive bladder.

[0008] Document EP 3 122 233 B1 discloses a medical device system for delivering energy to a region of a patient's anatomy, the medical device system comprising: an introduction tube defining a lumen therein, the introduction tube being configured to be introduced into the patient's anatomy, the introduction tube being a first electrode;and a second electrode movable within the lumen of the introduction tube between a retracted position and an extended position, wherein the second electrode is disposed substantially within the lumen in the retracted position, and wherein the second electrode, in the extended position, extends at least partially beyond the distal end of the introduction tube, wherein the first and second electrodes are configured to deliver energy to tissue, wherein the introduction tube is configured to maintain the second electrode within the lumen substantially in a predetermined orientation in the extended position, wherein the introduction tube prevents the second electrode from substantially rotating within the lumen of the introduction tube during movement to the extended position.;

[0009] US 2014 / 046320 A1 discloses a multifunctional medical device comprising a sheath having a proximal end, a distal end, and a lumen extending between the proximal and distal ends. The medical device further includes an end effector slidably disposed within the lumen. A portion of the end effector can be configured to transition between a collapsed state within the lumen and an expanded state outside the lumen.

[0010] US 2008 / 015409 A1 discloses a treatment device for endoscopes used for cutting body tissue, wherein the treatment device retractably protrudes from a catheter. The treatment device comprises a control wire inserted into the catheter and a cutting electrode attached to the distal end of the control wire, wherein the cutting electrode is pre-curved. The cutting electrode elastically deforms when retracted into the catheter, assuming a shape similar to the configuration of the catheter.

[0011] Surgery using such large-bore, rigid surgical instruments represents a surgical procedure for the patient, requiring general anesthesia or at least spinal anesthesia. Such procedures, such as prostate resections, are typically performed as part of an inpatient stay. Furthermore, there is an increased risk of organ injury and bleeding when inserting them through the respective anatomical access routes and handling the large-bore, rigid surgical instruments.

[0012] The object of the present invention is therefore to provide a surgical instrument which can be subjected to high-frequency current and which is intended for insertion into a flexible endoscope (e.g. cystoscope), which is characterized by a smaller space requirement when guided within the flexible endoscope compared to conventional resectoscopes, whereby the spatial extent of the resectoscope as a whole in the anatomical access route and in the organ in question is significantly reduced. Description of the invention

[0013] The invention relates, in a first aspect, to a surgical instrument for insertion into a flexible surgical endoscope having a tubular working shaft which comprises at least one instrument channel having a proximal and a distal end and running along the length of the working shaft for receiving at least one surgical instrument. The term "proximal" refers to the part of the working shaft closest to the user, while the term "distal" refers to the part of the working shaft remote from the user. The surgical instrument is adapted to couple to an electrical waveform generator and receive an electrical waveform. The instrument can therefore be supplied with high-frequency (HF) alternating current, whereby, for resecting, HF current is passed via the instrument through the body part to be treated and the instrument is operated as an electrical cutting tool.This enables precise incision guidance with minimal blood loss. Such surgical instruments known from the prior art are used, for example, for the resection of a hypertrophied prostate starting from the urethra. A distal end of the surgical instrument according to the invention, which can be mounted longitudinally displaceably in the instrument channel, is formed with a cutting tool. Upon and / or after exiting the distal end of the instrument channel, the cutting tool according to the invention of the surgical instrument spreads open. The term "spreading open" is understood to mean a change in state of the cutting tool during and / or after exiting, whereby the cutting tool as a whole or individual parts thereof stretch away from one another as far as possible with respect to the longitudinal axis of the instrument, predominantly in a lateral direction (to the lateral).As a result, after this change of state, the cutting tool is in a "working position" and can be used for electrically cutting and coagulating the tissue of interest. In the "working position", the cutting tool preferably has a Y-shape. By spreading it open, the cutting tool can be transferred from a "resting position" to a "working position". The small spatial extension of the cutting tool laterally relative to the diameter of the instrument channel in the resting position advantageously enables the instrument to be used in a flexible endoscope with a working shaft that is significantly smaller than that of conventional resectoscopes. The surgical instrument according to the invention advantageously enables the use of endoscopes with a smaller working shaft diameter than that of resectoscopes, whereby the endoscopes are also flexible and thus adapt better to the anatomy.This minimizes the risks for the patient regarding injury to surrounding tissue and bleeding during insertion and handling of the endoscope. For example, when using a flexible cystoscope with a reduced diameter working shaft, a procedure on the prostate for benign prostatic hyperplasia can be performed under local anesthesia on an outpatient basis; an inpatient stay is not necessary. Particularly in this type of procedure, the use of the instrument according to the invention can prevent postoperative disturbances of sexual function. Advantageously, the overall procedure time is significantly reduced due to the use of only local anesthesia and the significantly lower trauma for the patient.

[0014] In an advantageous embodiment, the cutting tool of the surgical instrument can spread open due to spring force, either upon exiting and / or after exiting the distal end of the instrument channel. The cutting tool is therefore designed as a spring, whereby a spring is understood to be a technical component that is used to store forces. The cutting tool is accordingly in a tensioned state in the instrument channel (as a carrier of potential energy) and upon and / or after exiting, the cutting tool is released. The cutting tool is preferably designed as a leg spring or a torsion spring. A leg spring is a coiled spring with protruding, preferably straight ends (legs). A torsion spring is a largely rod-shaped spring, whereby the spring effect is achieved by twisting the rod.A cutting tool designed as a spring is advantageously characterized by its ease of manufacture and low manufacturing costs. Expanding such a cutting tool requires no separate guides or actuating means to control the expansion of the cutting tool or individual components. Furthermore, such a cutting tool can be easily dimensioned according to the surgical application, eliminating the space required for additional guides and actuating means.

[0015] In an advantageous development of the instrument, the spreading of the cutting tool can be controlled by a guide channel in which the instrument with the distal cutting tool can be movably mounted and which, in turn, is arranged so that it can be longitudinally displaced within the instrument channel. Due to the relative movement of the cutting tool relative to the guide channel, the latter can be in an expanded position (cutting tool not in the guide channel) or in a non-spread position (cutting tool in the guide channel).

[0016] In an advantageous development of the instrument, the cutting tool can be connected to a guide and an actuation mechanism for controlling the spreading. Using the guide and the associated actuation mechanism, the user can control the spreading of the cutting tool, for example, via a pull or push mechanism. An instrument designed in this way enables precise and needs-adapted control of the cutting tool or parts thereof by the user.

[0017] In a further embodiment, the cutting tool can be designed as an arrangement of needle electrodes with at least two arms. In the spread state, a cutting tool designed with two arms can, for example, assume a rod-like shape, wherein the first and second needle electrodes are connected to one another at their proximal ends and simultaneously to the part of the instrument located more proximal to the cutting tool, the cutting tool carrier adjacent to the cutting tool. A needle electrode is understood to be a wire coated with an insulating material except for the tip. In the case of a monopolar needle electrode, a corresponding reference electrode must be provided. A bipolar needle electrode usually comprises at least two mutually insulated wires in a cylinder; the current flows between the wires.The arrangement of the needle electrodes at the distal end of the instrument can be individually adapted to the specific surgical site. For example, for a prostate resection, a cutting tool with a two-arm arrangement of needle electrodes can be selected, with the first and second electrodes aligned with each other, allowing the incision and resection of the organ arranged around the anatomical access route to be performed in two locations simultaneously. For the treatment of an organ that requires resecting only in specific areas, a different arrangement can be selected, for example, in a U- or V-shape, or, if a comprehensive resection with multiple incisions is required, a star-shaped arrangement.A cutting tool designed in this way can be compactly dimensioned in the resting state, depending on the surgical area, so that it can be easily inserted into an instrument channel of the working shaft of a flexible endoscope and moved within it to reach the working position. During and / or after spreading, the expansion required for use of the cutting tool, primarily laterally but also distally, relative to the instrument channel, can be easily achieved.

[0018] In a preferred embodiment, the cutting tool can be designed as a three-armed arrangement of needle electrodes. Particularly preferably, the cutting tool can be designed as a Y-shaped arrangement of needle electrodes. Such a cutting tool is small enough to fit the surgical site when at rest (see above), so that it can be easily inserted into an instrument channel of the working shaft of a flexible endoscope and moved distally therein to reach the working position. The needle electrodes can be extended laterally in three different directions, with adjacent needle electrodes being arranged, for example, at an angle of 120° to one another.A three-arm cutting tool combines the advantages of space-saving storage in the instrument channel in the resting position with a large reach in the working position, allowing the surgical procedure to be performed comprehensively, gently, and time-savingly. For example, during a prostate resection, the organ can be incised and resected simultaneously at three locations under constant visual control.

[0019] In a preferred embodiment, a connection point of the needle electrodes can form the most distal end of the surgical instrument when the cutting tool is moved to the distal end of the instrument channel. The connection point refers to the point on the cutting tool at which, for example, the proximal end of the first needle electrode is connected to the proximal end of the second needle electrode and, at the same time, to the cutting tool carrier, i.e., the section of the instrument according to the invention located proximal to the cutting tool. A cutting tool configured in this way remains in a largely non-spread state until it completely exits the instrument channel.Due to the proximal orientation of the potentially sharp distal ends of the needle electrodes during displacement of the instrument distally toward the surgical site, the instrument can be advantageously advanced distally in a simple manner, even in a largely flexible instrument channel of a flexible endoscope. After the cutting tool has completely emerged from the instrument channel, the needle electrodes can be spread laterally, for example, by spring force, from their resting position to a working position with maximum extension. To return the instrument to the instrument channel after completion of the surgical procedure, the cutting tool can be retracted into the instrument channel by the user.The spring formed by the electrode arms and the connection point is selected with respect to its spring force F such that, on the one hand, a "passive" spreading into the unclamped working state is possible during and / or after exiting, and, on the other hand, the electrode arms can be easily bent in the direction opposite to the resting state of the cutting tool for return to the instrument channel. Such an instrument is characterized by its simple design and low manufacturing costs, which is particularly advantageous since it is preferably an instrument for single, i.e., patient-specific, use.

[0020] In the opposite case, namely when the distal tips of the needle electrodes are located further distally than the connection point during advancement, a slight curvature of the tips medially, i.e., toward the central axis of the instrument, can allow the instrument to be advanced smoothly within the instrument channel. A cutting tool designed in this way can be easily retracted into the instrument channel after the surgical procedure and, if necessary, removed from it again. This design can be used primarily with reusable instruments.

[0021] In a particularly preferred development, the cutting tool can be designed as a torsion spring (V-spring) or, in particular, as a torsion spring with two spring legs connected by a spring body, the leg position being 180° in the tensioned state and up to 0 / 360° in the working state. It is preferably a torsion spring with a number of coils between 0.5 and 3. The spring body can accordingly advantageously be designed as a largely U-shaped arc, with the spring legs emerging from the arc legs. A cutting tool designed as a torsion spring is subjected to deformation upon return from the working state into the working channel of a flexible endoscope. This deformation is permanent if, upon reverse loading (directed against the winding direction) of the leg spring, the bending stress exceeds the permissible value of the yield point.Therefore, the spring stiffness and spring material are expediently selected so that, for example, an arrangement of needle electrodes spreads out after emerging from the instrument channel and can be returned through the instrument channel after completion of the surgical procedure, for example a prostate resection, so that the arrangement is flexible in both directions.

[0022] In a further, alternative embodiment, the cutting tool can be designed as a spiral spring. The spring expands upon and / or after exiting the instrument channel, primarily in a lateral, but also distal direction, relative to the longitudinal axis of the instrument. A cutting tool designed as a spiral spring is characterized by its ease of use: after being expanded into the working position, the spiral spring can be rotated by the user along the longitudinal axis of the cutting tool holder in the instrument channel to optimally reach the corresponding surgical regions.

[0023] In an advantageous development, the cutting tool can comprise a material with spring properties selected from the group consisting of a metal and a metal alloy. Particularly advantageously, the cutting tool can comprise spring steel, stainless steel, and / or platinum-iridium alloys. Spring steel is understood to be a steel that has higher strength than other steels.

[0024] In a further advantageous embodiment, the diameter of a circle defined by a circular line connecting the distal ends of the cutting tool spread open in the working state can be larger by a factor of 1.25 to 4 than a diameter of a distal portion of the flexible endoscope, particularly preferably by a factor of 1.45 to 3. By means of a cutting tool dimensioned in this way, the treated tissue can be reached via narrow access paths and, at the same time, a resection area located deeper in the tissue can be reached.

[0025] In a preferred embodiment, the cutting tool can be rotated about its longitudinal axis by means of an actuation arranged at a proximal end of the surgical instrument. While the manual rotation of the resectoscope with the instrument arranged in the instrument channel of the working shaft enables rotation of the cutting tool by pronation (inward rotation) or supination (outward rotation) of the hand of the surgeon (user) holding the instrument, rotation via an additional actuation can advantageously enable fine adjustment of the cutting tool in the surgical field. This is particularly advantageous if, for example, a two-armed cutting tool is to be used to resect an organ arranged over a large area around the cutting tool, e.g., a prostate.

[0026] In an advantageous development, the instrument comprising the cutting tool can be designed as a bipolar electrode. For example, an instrument with a cutting tool designed as a two-armed needle electrode can be configured so that current flows from one needle electrode to the other. Such arrangements are known, for example, for bipolar alligator forceps, which are used, for example, in laparoscopic surgery. The close spatial arrangement of the electrodes makes it possible to vaporize the tissue fluid or a rinsing fluid surrounding the tissue in a narrowly defined area; a thin gas layer (plasma pocket) forms around the electrodes, which grows with energy input and forms a larger gas bubble with high-energy ions. Plasma vaporization is particularly suitable for prostate resection.

[0027] In a further embodiment, the instrument displaceably arranged in a guide channel can comprise a cutting tool configured as an active electrode, wherein the guide channel can be configured as a return electrode at least in one region. This configuration can be used, for example, in the case where the cutting tool is configured as a spiral spring. The spiral spring can be moved via a guide channel to the tip of the instrument channel, wherein the instrument with the distal cutting tool is movably mounted in the guide channel.Through the relative movement of the cutting tool and guide channel, for example, via a proximally arranged actuation, the user can push the cutting tool, designed as a spiral spring, out of the guide channel and the corresponding instrument channel. For example, the guide channel can only be pushed to the distal end of the instrument channel, while the spiral spring can completely exit it. The close spatial proximity between the spiral spring and the return electrode enables the generation of plasma with a largely low energy input, thus enabling precise operations with minimal damage to surrounding tissue.

[0028] In a second aspect, the invention relates to a surgical endoscope comprising the surgical instrument described above, wherein the working shaft of the surgical endoscope, into which the surgical instrument according to the invention is inserted via the instrument channel, can have at least one bendable region along its longitudinal axis. The working shaft is therefore preferably designed such that it can be bent at least in a partial region. An endoscope designed in this way enables a further reduction in the traumatic stress on the patient during insertion of the flexible endoscope and during a procedure, since the working shaft can adapt better to the anatomical leads and structures in the surgical field than with rigid devices.A conventional flexible endoscope, such as a cystoscope, is designed so that the bending of at least one accessible area can be controlled by the user (flexion or deflection). For example, the use of a flexible cystoscope enables a complete inspection of the bladder, since both the light source and the optics can be optimally aligned via the flexion or deflection of the working shaft.

[0029] In a preferred embodiment of the endoscope into which the instrument according to the invention can be inserted, the working shaft can be flexible along its entire longitudinal axis. Particularly for operations on organs with long, small anatomical leads, such as the urethra or ureter, maximum flexibility is advantageous in terms of a gentle, largely atraumatic surgical technique.

[0030] In an advantageous development, the flexible surgical endoscope into which the instrument according to the invention can be inserted can be a laryngoscope, nephroscope, sinusoscope, ureterorenoscope, cystoscope, hysteroscope, or otoscope. The corresponding surgical endoscopes can be available as conventional, rigid devices or as flexible devices. Due to its small distal diameter when at rest, the instrument according to the invention can advantageously be used in flexible surgical endoscopes that are smaller than conventional resectoscopes and are used for operations in anatomically difficult-to-access surgical areas. The use of a flexible endoscope can advantageously significantly facilitate access to, for example, the kidney (nephroscope, ureterorenoscope), the ureters (ureteroscope), and the paranasal sinuses (sinusoscope). Description of the characters

[0031] In the following, some specific embodiments of the invention are described by way of example and not exhaustively, with reference to the accompanying figures. These specific embodiments serve only to illustrate the general inventive concept; they do not limit the invention. Fig. 1A to 1C show an oblique lateral perspective view of the distal end of the working shaft of a flexible endoscope in which the surgical instrument according to the invention is guided, the cutting tool of which is designed as a three-armed arrangement of needle electrodes. Fig. Figure 2 shows the corresponding view of the distal end of the working shaft of a flexible endoscope, wherein the cutting tool of the surgical instrument is designed as a spiral spring.

[0032] Fig. 1A to 1C show an oblique lateral, perspective view of the distal end of a flexible endoscope with a working shaft (1) which is formed with an instrument channel (2). The instrument channel is arranged at approximately 12:00 o'clock in the illustration and runs along the longitudinal extent of the working shaft over its entire length from the proximal end (3, left side of the image), i.e. facing the user, to the distal end (4, right side of the image), i.e. facing away from the user. Also arranged in the working shaft is a distal lens (5), which focuses the image of the corresponding organ and transmits it to the proximally located eyepiece (not shown) by means of the fiber bundle located proximal to the lens (5) and adjoining it.The area of ​​interest can be illuminated using two fiber optic light guides (6); the light guides (6) direct the light from an external light source (not shown) into the area of ​​interest. The tip of the working shaft is approximately hemispherical to avoid sharp corners and edges and to minimize the risk of organ injury and bleeding during insertion and handling. Fig. Figure 1A shows the distal end of the instrument according to the invention with a cutting tool (7) in the instrument channel (2). The cutting tool (7) is designed as a three-armed needle electrode (9), wherein Fig. 1A, only two arms of the needle electrode (9) can be seen, which rest against the cutting tool carrier (8) and whose distal ends are still located in the instrument channel (2). The connection point (10), which is formed by the proximal ends of the three needle electrodes and the distal end of the cutting tool carrier (8), forms the distal end of the cutting tool (7) of the surgical instrument in the configuration shown before the cutting tool (7) completely emerges from the instrument channel (2). Fig. 1A Arrow pointing to the right indicates the forward movement of the instrument (7) in the instrument channel (2) of the working shaft (1). Fig. Figure 1B shows the change in state of the cutting tool (7) after it has completely emerged from the instrument channel (2) by spreading (dashed arrows). The three needle electrodes move from a tensioned rest position of the cutting tool (7) in the instrument channel (2) relative to the connection point (10) or the longitudinal axis of the instrument (7) distally and laterally. Fig. 1C shows the cutting tool (7) in its fully expanded working position. The needle electrodes are connected to each other and to the cutting tool carrier (8) at the connection point (10). To avoid organ injuries caused by the spreading of the cutting tool (7), the alignment of the cutting tool (7) is preferably carried out under visual control, either in a hollow organ that is larger than the cutting tool in its maximum lateral extent, or in a correspondingly dimensioned anatomical guide connected to the organ to be treated. Fig. Figure 1C shows the corresponding positioning of the cutting tool (7) in a prostate (11) to be resected. The three-armed needle electrode (9) incises the prostate (11) at three different locations, starting from the urethra (12). With a cutting tool (7) designed as a bipolar electrode, localized plasma can be generated, allowing the tissue to be removed gently and precisely.

[0033] Fig. Figure 2 shows a cutting tool (7) designed as a spiral spring (13) in the expanded state after completely exiting the instrument channel (2). The spiral spring (13), which is movably mounted in the instrument channel (2) while tensioned in the resting state, can partially expand upon exiting the instrument channel (2), depending on the spring constant.

[0034] The spiral spring (13) shown can be rotated by actuation, thus enabling precise alignment of the cutting tool relative to the organ to be treated. Since the cutting tool (7), designed as a spiral spring (13), can expand significantly upon exit, the size of the cutting tool relative to the tissue to be treated can be flexibly adjusted by the user and can, for example, also be changed during the operation. List of reference symbols 1 work force 2 instrument channels 3 proximal end of the working shaft 4 distal end of the working shaft 5 distal lens 6 fiber optic light guide 7 Cutting tool at the distal end of the surgical instrument 8 cutting tool carriers 9 Needle electrode 10 connection point 11 Prostate 12 Urethra 13 Spiralfeder

Claims

[1] Surgical instrument for insertion into an endoscope, preferably a flexible endoscope, with a tubular working shaft which comprises at least one instrument channel having a proximal and a distal end and running along the length of the endoscope for receiving at least one surgical instrument, wherein the surgical instrument is adapted to couple to an electrical waveform generator and to receive an electrical waveform, wherein a distal end of the surgical instrument, which can be stored longitudinally displaceably in the instrument channel, is formed with a cutting tool, where the cutting tool spreads during and / or after exiting the distal end of the instrument channel of the surgical endoscope and wherein the cutting tool is designed as an at least two-armed arrangement of needle electrodes characterized by , that a proximal end of a first needle electrode and a proximal end of a second needle electrode and a cutting tool carrier are connected to each other at a connection point of the cutting tool, wherein a spring is formed by the needle electrodes and the connection point, wherein the spring force F of the spring is selected such that, on the one hand, a passive spreading into the untensioned working state is possible during and / or after exiting the instrument channel and, on the other hand, the needle electrodes are provided to be bent in the direction opposite to the resting state of the cutting tool for return into the instrument channel. [2] Surgical instrument according to claim 1, wherein the cutting tool is connected to a guide and an actuator for controlling the spreading. [3] Surgical instrument according to one of the preceding claims, wherein the cutting tool is designed as a three-armed arrangement of needle electrodes. [4] Surgical instrument according to claim 1, wherein the cutting tool is designed as a spiral spring. [5] Surgical instrument according to one of the preceding claims, wherein the cutting tool can be rotated about the longitudinal axis of the surgical instrument by means of an actuation arranged at a proximal end of the surgical instrument. [6] Surgical instrument according to one of the preceding claims, wherein the cutting tool is designed as a bipolar electrode. [7] Surgical instrument according to one of the preceding claims, wherein the cutting tool is designed as an active electrode, and wherein the instrument is displaceable in a guide channel, wherein the guide channel is designed as a return electrode at least in one region. [8] Surgical endoscope comprising the surgical instrument according to one of the preceding claims, wherein the working shaft of the surgical endoscope has at least one bendable region along its longitudinal axis. [9] Surgical endoscope according to claim 8, wherein the working shaft of the surgical endoscope is bendable along its longitudinal axis over the entire range. [10] A surgical endoscope according to any one of claims 8 or 9, wherein the surgical endoscope is a laryngoscope, nephroscope, sinusoscope, ureterorenoscope, cystoscope, hysteroscope or otoscope.

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