Device for endoscopically removing stone or calculus from biliary tract and pancreatic duct and replacement method of device disposed in working channel of medical endoscope

Abstract

To provide a device for removing stones or calculi from a biliary tract and a pancreatic duct with an endoscope.SOLUTION: A device for endoscopically removing stones or calculi from a biliary tract and a pancreatic duct includes: a control wire being guided in a tube; a control element for axially moving the control wire in the tube, fixed to a proximal end of the control wire; and a catch basket composed of basket wires, fixed to a distal end of the control wire. The catch basket expands or contracts into a loop by axial movement of the control wire by the control element. The purpose thereof is to create advantageous possibilities for handling such a device, when lithotripsy is required. The control wire is separable from the control element and can be coupled to an actuating element for the lithotripsy of a stone contained by the catch basket, where the actuating element can be used to generate sufficient force on the catch basket.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a device for endoscopically removing stones or calculi from the biliary and pancreatic ducts. The device has a control wire guided in a tube, a control element at its proximal end for axially moving the control wire in the tube, and a catch basket made of a basket wire fixed at its distal end. The catch basket is expanded or contracted in a loop shape by axially moving the control wire by the control element.

[0002] Furthermore, the invention relates to a method for converting a device placed in the working channel of a medical endoscope, which can be performed after endoscopic retrograde cholangiopancreatography, for use in lithotripsy and removal of stones captured by a catch basket, the device comprising a tube, a control wire guided within the tube, a catch basket distally connected to the control wire for accommodating the stone, and a control element engaging the tube and the control wire, the catch basket being expanded or contracted in a loop by axial movement of the control wire by the control element. [Background technology]

[0003] Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic procedure used to visualize and examine a patient's bile and pancreatic ducts. A medical endoscope is inserted through the pharynx into the patient's esophagus, and the distal end of the endoscope is equipped with a camera designed as a side-viewing optics, which passes through the stomach and into the duodenum. To further examine the patient's bile and pancreatic ducts and to consider possible treatments, various endoscopic devices equipped with distal instruments are guided through the working channel of the medical endoscope into the area of ​​the bile and pancreatic duct to be treated. These devices can be used to open stenosed or blocked ducts, remove and / or crush gallstones as part of a lithotripsy procedure, perform biopsies, and possibly surgically remove tumors in the area of ​​the ducts, or insert stents into the ducts. When using endoscopic retrograde cholangiopancreatography (ERCP) after papillotomy, the gallstones are usually removed using a catch basket. A catch basket is also suitable for safely removing stone fragments from the bile duct.

[0004] A device for endoscopically removing stones or calculi from the bile and pancreatic ducts of the type mentioned in the general terms of claim 1 is known from German published patent application 10 2009 031 209. The device has a cable guided in a tube, at the proximal end of which a control element is arranged for axially moving the cable in the tube and at the distal end of which a catch basket formed from at least four elastic basket wires is arranged. When the cable is axially moved by the control element, the catch basket is drawn in a loop or is widened as it is pulled towards the distal end of the tube and partially enters its lumen. This catch basket is used to capture gallstones released from the papilla and is constricted at the same time as it is rotated and moved to capture the gallstones. Gallstones captured between the basket wires are fixed in the catcher basket and can be removed from the bile and pancreatic ducts.

[0005] A significant problem always occurs when the size of the stone does not allow it to be extracted and removed through a body opening such as the bile duct. Forcibly removing the stone would cause significant damage to the patient undergoing the procedure. The only options to address this problem are to apply force to the stone through the catch basket to perform lithotripsy, or to design the catch basket so that it can be actuated via an endoscopic device to release the stone and the device can be removed from the bile duct after it has been separated from the stone.

[0006] Furthermore, German published patent application 32 16 178 discloses a device for mechanical lithotripsy and removal of stones formed in the bile duct. The device consists of an extractor, which can be combined with a lithotripsy device if necessary. The extractor has a control device in the form of a handle, which is connected to a push rod and a sleeve which holds the push rod. The push rod is guided telescopically in the sleeve and, at its end remote from the handle, is fixed to a pull cable which is connected to a stone retrieval basket. As a result, the axial movement of the push rod in the sleeve opens or closes the stone retrieval basket depending on the direction of movement, so that stones present, for example, in the bile duct can be picked up by the stone retrieval basket and removed from the patient's body by moving the entire device in the proximal direction.

[0007] According to German Patent Application 32 16 178, in addition to the extractor, a separate lithotriptor is provided which is optionally fixed to the operating element. This is a tensioning element with a radially extending bracket, which, after the lithotriptor is attached, engages on the one hand with the handle of the first operating element and on the other hand with a headpiece connected to the sleeve. If it is determined that the stone has dimensions that make it difficult to remove easily, the lithotriptor attached to the operating element applies a strong tensile force to the cable, so that the stone in the quarry basket is broken into several small fragments. These fragments can then be removed together with the quarry basket. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the invention is to improve a device for the endoscopic removal of stones or calculi from the bile and pancreatic ducts in such a way that more favorable possibilities arise with regard to the required lithotripsy. [Means for solving the problem]

[0009] This problem is solved on the basis of the general terms of the claims having the characteristic features. The claims dependent on claim 1 contain further embodiments of this solution according to the invention.

[0010] As a result, a device is provided for endoscopic removal of stones or calculi from the bile and pancreatic ducts. The device has a control wire guided within a tube. A control element for axially moving the control wire is attached to the proximal end of the control wire passing through the tube, while a catch basket made of a basket wire is attached to the distal end of the control wire. Axial movement of the control wire by the control element expands or contracts the catch basket in a loop. Thus, the control element can be used to perform precise movements to capture the stone and safely corral it for removal.

[0011] According to the invention, the control wire should be separable from the control element and should be connectable to an actuation element capable of exerting a sufficient force on the catch basket in order to perform lithotripsy on the stone contained by the catch basket. As already explained, if the stone picked up by the catch basket has dimensions that prevent its removal from the bile duct, then the stone requires lithotripsy. This can be done by exerting a force on the catch basket holding the stone, which narrows by being partially drawn into the lumen of the tube via the control wire, so that the stone broken by mechanical lithotripsy is broken into multiple stone fragments that remain in the catch basket.

[0012] The control element acting on the control wire is preferably equipped with a thumb ring and two finger rings as a slider for one-handed operation, but without the ability to apply the required tension. In the solution according to the invention, the control element is replaced by an actuating element suitable for the following lithotripsy. For this purpose, the control element is separated from the control wire, which is then coupled to the actuating element.

[0013] In contrast, according to the general German published patent application 10 2009 031 209, an endoscopic device is intended for removing gallstones by means of a catch basket, but with this device no mechanical lithotripsy is performed, since the control elements are only intended to effect movements to expand and contract the catch basket, and therefore the control elements provided on the device cannot be used to generate the tensile forces required for mechanical lithotripsy on the catch basket.

[0014] Further prior art, German Published Patent Application No. 32 16 178, provides a further lithotriptor, which, if necessary, must be fixed to a control element, so that a sufficient tensile force can be applied to the control wire. However, this lithotriptor is not suitable for combination with all kinds of control elements. In particular, this lithotriptor cannot be combined with conventional control elements which can be operated with one hand and which have a thumb ring and two finger rings.

[0015] The working element should be designed and dimensioned to be able to exert a tensile force of up to 500 N for lithotripsy of stones picked up by the catch basket. This high tensile force should generate enough force in the catch basket to crush the stones, but should not cause plastic deformation of the working element or make it brittle. A tensile force of 200 N is required to crush a gallstone with a diameter of about 1 cm.

[0016] In a further embodiment of the invention, the traction means extends from the actuation element and is connectable to the control wire by a form-fitting connection, so that the control wire separated from the control element is connected to the traction means in a form-fitting manner. The interlocking of the two components, the traction means and the control wire, forms a form-fitting connection acting in the direction of the pulling force.

[0017] In a further embodiment of the invention, the form-fitting connection should be designed as a hook-eyelet connection, where a hook preferably formed on the control wire is hooked into the distal eyelet of the traction means, thus transmitting the high tensile forces generated by the actuation element using simple means.

[0018] It is further contemplated that after separation from the control element, the proximal end of the control wire can be provided with a kink, with the kinked end running generally parallel to the control wire, and the kink can provide a hook for a form-fitting connection with the eyelet and a means for preventing the hook from disengaging from the eyelet under high tensile forces.

[0019] Furthermore, means for fixing the kink should interact with the proximal end. These means prevent the kink from bending open under the high tensile forces transmitted to the kink by the eyelet. These means are preferably made by drawing the proximal ends of the control wires, which are hung on the eyelets of the traction means, into the lumen of the metallic helical tube, thus ensuring that the kink is prevented from bending open. The diameter of the lumen formed in the helical hose is dimensioned in such a way that, on the one hand, the proximal part can be drawn in and moved inside it, and, on the other hand, a radially acting tension acts on the bent proximal end receiving the eyelet, which allows the transmission of high tensile forces through this connection.

[0020] The actuation element is also provided with a shaft extending in the same longitudinal direction as the traction means, on which a tensioning device extending transversely to the shaft is rotatably mounted, through which the proximal end of the traction means is threaded. The proximal end of the traction means, designed as a wire or cable, is wound around the tensioning device, designed as a spool, by the practitioner manually applying a rotational movement to the tensioning device.

[0021] In a further embodiment of the device according to the invention, the kink in the proximal end of the control wire can be made by a tool with two tool parts which undergo angular movement relative to each other. According to a first embodiment, the tool can have two legs connected to each other via a hinge, and the control wire can be fixed to one of the legs. The legs are preferably designed as flat plastic parts connected to each other via a hinge at one of their ends.

[0022] According to a second embodiment, the tool may also be provided with an annular base having a holding grip in which the disk is rotatably guided, the proximal end being inserted radially through an insertion opening in the base and into both the base and the adjacent driver of the disk, the proximal end then deforming into a hook shape when the disk is rotated relative to the base.

[0023] Additionally, a tool having hinged legs may have aligned grooves for receiving the control wires, and at least one leg may include a clamp for securing the control wire.

[0024] Moreover, the problem underlying the present invention is also solved in the context of a method for transforming a device placed in the working channel of a medical endoscope and used after endoscopic retrograde cholangiopancreatography, said device being used for lithotripsy and removal of stones captured by a catch basket, said device having a tube, a control wire guided in the tube, a catch basket distally connected to the control wire for accommodating the stone, and a control element engaging the tube and the control wire, said catch basket being expanded or contracted in a loop by axial movement of the control wire by the control element.

[0025] According to the present invention, the following process steps are provided: severing a proximal portion of a control wire that is guided within a guide shaft of a control element; bending a proximal end of the control wire to form a hook-like configuration; - hooking the hook-shaped proximal end of the control wire onto an eyelet of a traction means of an actuation element used for lithotripsy; applying tension to the actuation element to longitudinally move the hooked end of the control wire and the eyelet of the traction means into the metal spiral hose; Applying additional tension to the actuation element to apply force to the catch basket to crush the stones picked up by the catch basket.

[0026] As a further part of the method, after the kinked end has been hooked, the kinked end can first be manually pulled in the proximal direction until the eyelet comes into contact with the distal end of the spiral hose. The proximal end of the traction means is then connected to a tensioning device arranged on the actuation element and tension is applied to the traction means via the tensioning device designed as a take-up spool until the eyelet is forced into the spiral hose. Then, by further actuating the tensioning device, the tension force transmitted to the control wire is increased, and the catch basket is retracted until it moves to the distal end of the tube. Finally, by further increasing the tension force, the stones picked up by the catch basket are crushed.

[0027] The invention is not limited to the specified combinations of the features of independent claim 1 and the dependent claims and of process claim 9 and dependent claim 10. There are also further possibilities of combining individual features with one another, in particular when these arise from the claims, the advantages stated in connection with them, the following description of embodiments or directly from the drawings. Moreover, the reference in the claims to the drawings by the use of reference signs is in no way intended to limit the scope of protection of the claims to the examples of embodiments shown.

[0028] Further features of the invention will become apparent from the following description and from the drawings, in which simplified embodiments of the invention are shown. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 shows a perspective side view of the control elements of a device for endoscopic removal of stones or calculi from the bile and pancreatic ducts, with only a portion of the tubes visible. [Diagram 2] 13 shows a side view of the distal end of a control wire with a catch basket attached. [Diagram 3] This shows how, during a medical endoscopic procedure on a patient, it was determined that a stone picked up by the catch basket needed to be lithotripted with a relatively strong force, after which the control element was separated from the control wire using a side cutter. [Figure 4] 1 shows the proximal end of the control wire inserted into a tool used to bend the end of the control wire into a hook. [Diagram 5] 1 shows the proximal end of the control wire bent into a hook. [Figure 6] The drawing shows a towing means disposed within a metal spiral hose, with an eyelet formed at its distal end and coupled to a hook via the eyelet. [Figure 7] 1 shows an actuating element for lithotripsy to which the proximal end of the traction means is attached. [Figure 8] 5 shows the tool used in accordance with FIG. 4 to bend the proximal end of the control wire, ready for insertion of the control wire. [Figure 9] The tool of FIG. 8 is shown in a closed position with bending of the control wires being performed. [Figure 10] 13 shows another embodiment of a tool for bending control wires. [Figure 11] The actuation elements used are shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] In FIG. 1, 1 denotes a control element, from which extends a tube 2 and a control wire 3. The control wire 3 extends in the lumen of the tube 2, not shown in detail, and can be seen in FIG. 2. The control element 1 has a slider 4, which is connected to the proximal end of the control wire 3 and is guided in a longitudinal slot of a guide shaft 5, not shown in detail. This guide shaft 5 is further rigidly connected to the tube 2, so that the relative movements of the slider 4 with respect to the guide shaft 5 allow the control wire 3 to be moved back and forth within the tube 2. To achieve these movements, the guide shaft 5 is provided with a thumb ring 6 and the slider has two finger rings 7.

[0031] 2 shows the distal end of the control wire 3 when not covered by the tube 2, to which a catch basket 8 is fixed. The basket wires 9 of this catch basket 8, shown in an open state, are bound at one end to the end of the control wire 3 and at the other end to a cartridge-like guide element 10 which forms the distal end of the catch basket 8.

[0032] The tube 2 together with the control wire 3 and the catch basket 8 are preferably inserted into a working channel (not shown) of a medical endoscope that extends through the patient's pharynx, esophagus, and stomach to the area of ​​the patient's bile duct and pancreatic duct, where the catch basket 8 is initially in a closed position, in which it is fully contained by the tube 2. A guide wire, preferably inserted into the second lumen of the tube 2 via a guide wire, is inserted into a body opening and extends to the area where the stone is present under endoscopic or x-ray observation, thereby guiding the tube 2 containing the guide wire 3 and the catch basket 8 to that area.

[0033] The catch basket 8 is then actuated via the control element 1 to the open state shown in FIG. 2, which is due to the inherent tension of the catch basket 8. In this open position, the open catch basket 8 positioned by the control element 1 can pick up the stone. Preferably, the catch basket 8 undergoes a rotational movement during stone pick-up and subsequent closing movement by the control element 1, during which the catch basket 8 is supported at the distal end of the tube 2, which facilitates picking up the stone. During the subsequent pulling movement of the control wire 3, which is moved relative to the tube 2, the catch basket 8 contracts tightly around and surrounds the stone, so that it is supported within the catch basket 8 by the control wire 3 and the tube 2 and can be passed through the corresponding body opening to safely remove the stone.

[0034] However, serious problems arise when the stone is too large to be extracted through a body opening such as the bile duct. Forcibly extracting the stone would cause considerable trauma to the patient undergoing the procedure. However, even with the control element 1, which is primarily suited to locating and picking up the stone, it is not possible to transmit a traction force sufficient to crush the stone via the control wire 3 to the catch basket 8. The only option left is therefore to release the stone by opening the catch basket 8 via a release device provided in the catch basket 8. However, in order to pick up the stone in the basket of another lithotriptor, the aforementioned process must be repeated.

[0035] According to the invention, when lithotripsy of stones too large for normal removal is required, the tube 2 and the control wire 3 are proximally separated from the control element 1 by a side cutter 11, as shown in Figure 3. The control wire 3 is separated so that its proximal end 13 protrudes axially beyond the proximal end of the tube 2. As can be seen in Figure 4, this protruding end 13 of the control wire 3 is inserted into a tool 12 and fixed to this tool 12, as will be explained in more detail below in connection with Figure 8. The proximal end 13, shown in Figure 5, is bent into the shape of a hook using the tool 12, which forms a kink 13a in the proximal end 13.

[0036] As shown in Fig. 6, the hooked end 13 is provided on the distal side of a traction means 14 designed as a wire or cable and is hooked on an eyelet 15 having a diamond-shaped outer contour. The traction means 14 extends into the lumen 16 of a metallic helical tube 17 arranged in a tube 18. The diamond-shaped outer contour of the eyelet 15 ensures that the hooked end of the control wire 3 hung on the eyelet 15 is caught in the acute angled region 19 on the distal side of the eyelet 15, so that the eyelet wire 20 is pulled radially when the eyelet 15 is retracted into the lumen 16.

[0037] According to Fig. 7, the traction means 14 is manually pulled in the proximal direction and hung on the tensioning device 21 of the actuation element 22. The tensioning device 21 extends perpendicularly to the handle part 23 of the actuation element 22 and is rotatably attached to the actuation element 22. In this way, when the tensioning device 21 is manually actuated so as to perform a rotational movement relative to the handle part 23, this causes the traction means 14 to be wound up on the corresponding design part of the tensioning device 21.

[0038] As a result, the eyelet 15 protruding from the distal end of the tube 18 is pulled into the lumen 16 of the helical tube 17 together with the proximal end 13 of the control wire 3 hooked to the eyelet 15, as shown in Fig. 6. This causes an increase in tensile force in both the traction means 14 and the control wire 3 connected to the traction means 14, which is transferred to the catch basket 8 for lithotripsy of the corresponding stone.

[0039] The other figures 8 and 9 show different perspective views of the tool 12 used to bend the control wire 3, whose function has already been explained in relation to figure 4. The tool 12 consists of two legs 24 and 25, which are guided pivotally relative to one another and connected to one another via hinges 26 and 27. In figure 8 the tool 12 is in the open state and the surfaces 28 and 29 of the two legs 24 and 25 are visible, which are guided along the hinges 26 and 27 and moved towards one another when the control wire 3 is bent.

[0040] Surfaces 28 and 29 of legs 24 and 25 have aligned grooves 30 and 31 into which the control wire 3 is inserted prior to the bending process. The control wire 3 is then held in position in the two grooves 30 and 31 by a spring plate 32 on leg 24 and a clamp 33 located on leg 25. The tool 12 is then folded as shown in FIG. 9 and the proximal end 13 of the control wire 3 housed by the tool 12 is deformed into the hook-like configuration shown in FIG. 5.

[0041] Figure 10 shows another embodiment of a tool 34 consisting of an annular base 36 provided with a handle 35 and a disk 37 rotatably guided therein. In this case, the proximal end 13 shown in Figure 4 is inserted through an insertion opening 38 in the base 36 and into adjacent channels (not shown in detail) in the disk 37.

[0042] This is done with the disk 37 in the position indicated by the arrow 39 pointing to the "Start" mark relative to the base 36. The actuating lever 40 on the disk 37 is then used to rotate it clockwise from this position to the end position defined by the end stops 41 and 42. This causes a bend in the part of the inserted control wire 3 guided between the base 36 and the disk 37.

[0043] Finally, Figure 11 shows the actuating element 22 already described in relation to Figure 7, with the tensioning device 21 to which the traction means 14 is hung. The tensioning device 21 is formed with a knurled handle portion 43 extending at right angles to the shaft 44, which is rotated, which causes a proximal movement of the traction means 14 within the tube 18, so that the eyelet 15, which projects beyond the distal end of the tube, is drawn into the helical tube 17 arranged within the tube 18. [Explanation of symbols]

[0044] 1. Control Elements 2 Tubes 3 Control Wires 4 Slider from 1 5 Guide shaft from 1 Thumb ring from 6 1 7 Finger Ring from 1 8. Catch Basket Basket wire from 9 8 Cartridge-like guide elements from 10 8 11 Side cutter 12 Tools 13 Proximal end of 3 13a 13 Kink 14 Traction means 15 Eyelets 16 lumen 17 Spiral Hose 18 Tube 19 15 distal acute angle area 20 Eyelet Wire 21 Tensioning device 22 Actuating Elements 23 Handle 24, 25 legs 26, 27 Hinge 28 24 Regions 29 5th Region 30 28 grooves 31 29 Groove 32 Spring plate 33 Clamp 34 Tools 35 Handle 36 Base 37 Discs 38 Insertion port 39 Arrow 40 Operating lever End stop on 41 37 End stop on 42 36 43 Handle part from 21 Shaft from 44 22

Claims

1. A device for endoscopic removal of stones or calculi from the biliary and pancreatic ducts, comprising a control wire (3) guided in a tube (2), a control element (1) for axially moving the control wire (3) in the tube (2) at a proximal end of the control wire (3), a catch basket (8) made of a basket wire (9) fixed at a distal end of the control wire (3), the catch basket (8) being expanded or contracted in a loop by the axial movement of the control wire (3) by the control element (1), the control wire (3) being separable from the control element (1) and connectable to an actuating element (22) for lithotripsy of the stone contained by the catch basket (8), and the actuating element (22) being capable of exerting a sufficient force on the catch basket (8). Device.

2. 2. The device according to claim 1, characterized in that a tensile force of up to 500 N can be applied by means of the actuating element (22) to crush the stones.

3. 2. The device according to claim 1, characterized in that a traction means (14) extends from the actuation element (22) and is connectable to the control wire (3) by a form-fitting connection.

4. 4. The device according to claim 3, characterized in that the form-fitting connection is designed as a hook (13)-eyelet (15) connection.

5. The device according to claim 4, characterized in that after separation from the control element (1), the proximal end (13) of the control wire (3) is provided with a kink (13a), and the proximal end (13) with the kink extends at an acute angle or parallel to the control wire (3).

6. 6. A device according to claim 5, characterized in that the means for fixing the kink (13a) interact with the proximal end (13).

7. The device according to claim 5, characterized in that the proximal end (13) of the control wire (3), which is hung on the eyelet (15) of the traction means (14), is pulled together with the eyelet (15) into the inner lumen (16) of a metallic spiral tube (17) and serves as a fixing means for the kink (13a).

8. 4. The device according to claim 3, characterized in that the actuating element (22) has a shaft (44) extending in the same longitudinal direction as the traction means (14) and has a tensioning device (21) extending transversely to the shaft (44) and rotatably mounted thereon, the proximal end of the traction means (14) being capable of being hooked into the tensioning device (21).

9. 6. The device according to claim 5, characterized in that the kink (13a) of the proximal end (13) of the control wire (3) can be made by a tool (12, 34) having two tool parts (24 and 25, 36 and 37) that undergo angular movement relative to each other.

10. 10. The device according to claim 9, characterized in that the tool part is designed as two legs (24 and 25) connected to each other via a hinge, and the control wire (3) can be fixed to one of the legs (24).

11. 11. The device according to claim 10, characterized in that the legs (24 and 25) have aligned grooves (30 and 31) for receiving the control wire (3) and at least one of the legs (30, 31) is provided with a clamp (32, 33) for fixing the control wire (3).

12. A method for converting a device arranged in the working channel of a medical endoscope for use in the lithotripsy and removal of stones captured by a catch basket (8), which can be performed after an endoscopic retrograde cholangiopancreatography, said device comprising a tube (2), a control wire (3) guided in said tube (2), a catch basket (8) distally connected to said control wire (3) for accommodating stones, and a control element (3) engaging said tube (2) and said control wire (3), said catch basket (8) being expanded or contracted in a loop by axial movement of said control wire (3) by said control element (1), characterized in that the method comprises the following method steps: cutting a proximal portion of the control wire (3) guided within the guide shaft (5) of the control element (1); bending the proximal end (13) of the control wire (3) to form a hook-like configuration; hooking the hook-shaped proximal end (13) of the control wire (3) onto an eyelet (15) of a traction means (14) of an actuating element (22) used for lithotripsy; applying tension to the actuation element (22) to move the hooked end (13) of the control wire (3) and the eyelet (15) of the traction means (14) longitudinally into a metal spiral hose (17); Applying additional tension to the actuation element (22) creates a force on the catch basket (8), thereby crushing the stones picked up by the catch basket (8).

13. 13. The method according to claim 12, characterized in that after the end (13) provided with the kink (13a) is hooked, the end (13) is first manually pulled in the proximal direction until the eyelet (15) comes into contact with the distal end of the spiral hose (17), the proximal end of the traction means (14) is connected to the tensioning device (21) arranged on the actuation element (22) and tension is applied to the traction means (14) via the tensioning device (21) designed as a take-up spool until the eyelet (15) is forced into the spiral hose (17), then the tension transmitted to the control wire (3) is increased by further actuation of the tensioning device (21) until the catch basket (8) moves to the distal end of the tube (2), and the stones picked up by the catch basket (8) are crushed by further increasing the tension.

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