Medical Instrument and Method for Producing Same

Abstract

The present invention relates to a medical instrument (1), comprising a tool (10), a catheter assembly and a handle (20), by means of which the tool (10) can be actuated, and to a method for producing the medical instrument. The tool (10) is a wire construction having at least two wire portions (11′, 11″, 12′, 12″, 13′, 13″) and is arranged at a distal end of the catheter assembly. The catheter assembly is formed from an outer tube (3) and an inner tube (4), which is arranged coaxially to the outer tube. Furthermore, the medical instrument (1) has an optical waveguide (2), which extends through the inner tube (4) and the exit end (2′) of which opens into a space delimited by the tool (10). At least one first wire portion (11′, 12′, 13′) is fastened, at a proximal end (11a, 12a, 13a) thereof, to the distal end of the inner tube (4), and at least one second wire portion (11″, 12″, 13″) is fastened, at a proximal end (11b, 12b, 13b) thereof, to the distal end of the outer tube (3). The outer tube (3) and the inner tube (4) are movable relative to one another, and the tool (10) can be actuated for opening and closing by means of the relative movement between the outer tube (3) and the inner tube (4). The medical instrument (1) does not have a guide wire for actuating the tool (10).

Claims

1. Medical instrument (1) with a tool (10), a catheter assembly, and a handle (20), with which the tool (10) can be actuated, wherein the tool (10) is a wire structure with at least two wire sections (11′, 11″, 12′, 12″, 13′, 13″) and is arranged at a distal end of the catheter assembly, which is comprised of an outer tube (3) and an inner tube (4) arranged coaxially thereto, wherein the outer tube (3) and the inner tube (4) are movable relative to each other, wherein the medical instrument (1) moreover comprises an optical waveguide (2) that extends through the inner tube (4) and whose exit end (2′) ends coaxially in a space delimited by the tool (10), wherein the medical instrument (1) comprises no guide wire for actuation of the tool (10), wherein at least a first wire section (11′, 12′, 13′) with a proximal end (11a, 12a, 13a) is fastened to the distal end of the inner tube (4) and at least a second wire section (11″, 12″, 13″) with a proximal end (11b, 12b, 13b) is fastened to the distal end of the outer tube (3), and wherein the tool (10) for opening and closing is actuatable by the relative movement between the outer tube (3) and the inner tube (4).

2. Medical instrument (1) according to claim 1, wherein the optical waveguide (2) is a laser fiber (2) that is configured for guiding laser radiation of a thulium laser, wherein the laser fiber (2) comprises no buffering.

3. Medical instrument (1) according to claim 1, wherein the handle (20) comprises a handle body (20′) and at least one actuation element (21) for actuation of the tool (10), wherein a proximal end section of the outer tube (3) is connected to the actuation element (21), and a proximal end section of the inner tube (4) that projects in the handle (20) past the proximal end of the outer tube (3) is supported in the handle (20) so that the outer tube (3) is axially slidable relative to the inner tube (4) by means of the actuation element (21) for actuation of the tool (10), or a proximal end section of the outer tube (3) is supported in the handle (20) and a proximal end section of the inner tube (4) that projects in the handle (20) past the proximal end of the outer tube (3) is connected to the actuation element (21) so that the inner tube (4) is axially slidable relative to the outer tube (3) by means of the actuation element (21) for actuation of the tool (10).

4. Medical instrument (1) according to claim 3, wherein the actuation element (21) is a handle slide (21) that is slidable in axial direction relative to the handle body (20′) for movement of the outer tube (3), and/or the connection of the actuation element (21) to the proximal end section of the outer tube (3) is provided by a slide sleeve (22) that is connected to the actuation element (21) and in which a connection sleeve (23) is supported in which the outer tube (3) is fastened.

5. Medical instrument (1) according to claim 3, wherein the support of the proximal end section of the inner tube (4) in the handle (20) is provided by a fixation sleeve (25) in which the inner tube (4) is fastened and which is resting with its distal end against a support device that is provided between the proximal end of the outer sleeve (3) and the fixation sleeve (25) in the handle body (20′) or in a handle body attachment (26) that adjoins a proximal end of the handle body (20′).

6. Medical instrument (1) according to claim 5, wherein the support device is a spring (30) at whose proximal end the fixation sleeve (25) is resting, wherein the distal end of the spring (30) is supported at an annular shoulder (24′) that is provided in the handle body (20′).

7. Medical instrument (1) according to claim 6, wherein the annular shoulder (24′) is provided by a proximal end of a guide sleeve (24) that is arranged in the handle body (20′) for guiding the slide sleeve (22).

8. Medical instrument (1) according to claim 3, wherein the optical waveguide (2) projects past the proximal end of the inner tube (4) and extends through a proximal axial end section (27) of the handle (20) out of the handle (20), wherein the proximal axial end section (27) comprises an annular seal lip (28) that is contacting seal-tightly around the optical waveguide (2), wherein preferably the annular seal lip (28) is radially adjustable or comprises a radially adjustable opening cross section.

9. Medical instrument (1) according to claim 1, wherein the optical waveguide (2) is axially slidably arranged in the inner tube (4), wherein preferably the handle (20) comprises a second actuation element (40) that comprises a slide device or is connected thereto, that is operatively connected to the optical waveguide (2) and provides for an axial displacement of the optical waveguide (2), and/or the handle (20) comprises an insertion aid (29) with an insertion opening, tapering toward an inner cross section of the inner tube (4), for the optical waveguide (2) in the inner tube (4).

10. Medical instrument according to claim 1, wherein the wire structure of the tool (10) is a wire sling (11) which is formed of a first wire section (11′) and a second wire section (11″), or a stone basket (10) of two or three wire slings (11, 12, 13) which are each formed of a first wire section (11′, 12′, 13′) and a second wire section (11″, 12″, 13″).

11. Medical instrument according to claim 1, the wire structure is made of nitinol and comprises a pretension for the open position of the tool (10), and/or is provided at least partially by flat wire.

12. Medical instrument according to claim 1, the outer tube (3) is manufactured of a heat-resistant plastic material and/or the inner tube (4) comprises a fiber reinforcement with a friction-reducing plastic coating, wherein the fiber reinforcement is preferably a metal fiber reinforcement.

13. Medical instrument according to claim 12, wherein the attachment of the proximal end (11b, 12b, 13b) of the at least one second wire section (11″, 12″, 13″) at the outer tube (3) is provided by gluing, fusing and/or an additional shrink hose section that extends across a connection section at the end of the outer tube (3) and the proximal end (11b, 12b, 13b) of the at least one second wire section (11″, 12″, 13″), and/or the attachment of the proximal end (11a, 12a, 13a) of the at least one first wire section (11′, 12′, 13′) at the inner tube (4) a) is provided by gluing, fusing and/or an additional shrink hose section that extends across a connection section at the end of the inner tube (4) and the proximal end (11a, 12a, 13a) of the at least one first wire section (11′, 12′, 13′), or b) is provided by a friction and/or material-fused connection of the proximal end (11a, 12a, 13a) of the at least one first wire section (11′, 12′, 13′) with fiber ends of the fiber reinforcement which are present at the distal end of the inner tube (4), or c) is provided by an integral connection of the at least one first wire section (11′, 12′, 13′) with the metal fibers of the fiber textile reinforcement of the inner tube (4), wherein the at least one first wire section (11′, 12′, 13′) is formed of at least some of the metal fiber ends of the fiber textile reinforcement of the inner tube (4).

14. Method for producing a medical instrument (1) according to claim 1, comprising the steps forming a tool (10) of at least two wire sections (11′, 11″, 12′, 12″, 13′, 13″) to a wire structure and providing a catheter assembly of an outer tube (3) and an inner tube (4) coaxially arranged thereto and movable relative thereto, fastening a proximal end (11a, 12a, 13a) of at least one first wire section (11′, 12′, 13′) to the distal end of the inner tube (4), and fastening a proximal end (11b, 12b, 13b) of at least one second wire section (11″, 12″, 13″) to the distal end of the outer tube (3) so that the tool (10) is actuatable for opening and closing by the relative movement between the outer tube (3) and the inner tube (4) without guide wire, and coaxially inserting the optical waveguide (2) into and through the inner tube (4) so that an exit end (2′) of the optical waveguide (2) ends coaxially in a space delimited by the tool (10).

15. Method according to claim 14, comprising the steps prior to insertion of the optical waveguide (2) providing the optical waveguide (2) without buffering or removing the buffering from the optical waveguide (2), and/or providing a handle (20) with a handle body (20) and at least one actuation element (21) for actuating the tool (10), and connecting a proximal end section of the outer tube (3) to the actuation element (21), and supporting in the handle (20) a proximal end section of the inner tube (4) that projects in the handle (20) past the proximal end of the outer tube (3) so that the outer tube (3) is axially slidable by means of the actuation element (21) relative to the inner tube (4) for actuation of the tool (10).

Description

[0053] Further embodiments as well as some of the advantages which are associated with these and further embodiments be become clear and better understood by means of the following detailed description with reference to the accompanying Figures. Objects or parts thereof which are substantially identical or similar may be provided with the same reference characters. The Figures are only a schematic illustration of an embodiment of the invention.

[0054] It is shown in:

[0055] FIG. 1 a plan view of the medical instrument in an embodiment according to the invention;

[0056] FIG. 2 a section view through the medical instrument of FIG. 1 along section line B-B;

[0057] FIG. 3 an enlarged front view from the front of the stone basket of the medical instrument of FIG. 1;

[0058] FIG. 4 a detail section view of the detail D of FIG. 2;

[0059] FIG. 5 a schematic illustration of an embodiment of the handle body of a medical instrument according to the invention;

[0060] FIG. 6 a perspective view of an alternatively embodied stone basket of a medical instrument according to the invention;

[0061] FIG. 7 perspective views a), b), c) of alternatively embodied stone baskets of a medical instrument according to the invention;

[0062] FIG. 8 perspective views a), b) of alternatively embodied tools with a wire sling of a medical instrument according to the invention;

[0063] FIG. 9 a perspective view of a situation of use of a medical instrument according to the invention with the working tip with stone basket and laser extending from a working channel of an endoscopic instrument.

[0064] The invention concerns a medical instrument that employs at the same time a tool and an optical waveguide. In this context, the tool can be, for example, a grasping tool such as a stone basket that is combined with a coaxially arranged optical waveguide, e.g., a laser fiber as a lithotripter.

[0065] The optical waveguide, as a result of the employed thulium laser technology and of the embodiment according to the invention without buffering and due to the actuation of the tool without guide wire, can be embodied with significantly reduced diameter in comparison to conventional coaxial lasers and comprises thus a significantly improved flexibility with simultaneous good permanent and bending stability. In this context, the inner tube of the catheter assembly takes on a multi-functionality and provides, in addition to the protection of the optical waveguide, the stability of the catheter assembly and forms at the same time a part of the actuation mechanism of the tool.

[0066] Important for the elimination of a guide wire for a medical instrument 1, as illustrated in FIGS. 1 and 2, is the attachment of the tool 10, that is formed of connected wire sections, with the proximal wire ends to the distal ends of the outer and inner tubes 3, 4 of the catheter assembly. FIGS. 3 and 4 show this in detail with the example of an open stone basket 10 of the instrument 1 of FIGS. 1, 2 with three wire slings 11, 12, 13. The three wire slings 11, 12, 13 form each in plan view approximately a triangle with a first wire section 11′, 12′, 13′ whose proximal ends 11a, 12a, 13a are fastened to the inner tube 4 and with a second wire section 11″, 12″, 13″, whose proximal end 11b, 12b, 13b is connected to the outer tube 3. A wire section of each wire sling 11, 12, 13 that connects the first wire sections 11′, 12′, 13′ and second wire sections 11″, 12″, 13″, respectively, is not provided with reference characters herein.

[0067] In FIG. 3, for reasons of simplification of the illustration, a significant distance between the outer tube 3 and the inner tube 4 is shown in order to more clearly illustrate the principle of the connections of the proximal ends 11a, 12a, 13a, 11 b, 12b, 13b to the respective outer and inner tube 3, 4. Between the outer and inner tube 3, 4, as between the inner tube 3 and the optical waveguide 2, no significant radial clearance is provided. The diameters are selected so as to be matched such that the optical waveguide 2 can be inserted into the inner tube 4 and, as needed, can be displaced axially therein and that the outer tube 3 is axially moveable relative to the inner tube, but the coaxial arrangement of outer and inner tube 3, 4 with the optical waveguide 2 is ensured that determine the position of the tool 10 and enable that the optical waveguide ends coaxially in the tool 10.

[0068] So that the stone basket 10 can be actuated with the catheter tube assembly without guide wire, the proximal ends 11a, 12a, 13a of the first wire sections 11′, 12′, 13′ of each wire sling 11, 12, 13 are fastened to the inner tube 4 in which the laser fiber 2 is coaxially guided so that the exit end 2′ is positioned at the center of the stone basket 10 and an exiting laser beam extends coaxially, and the proximal ends 11b, 12b, 13b of the second wire sections 11″, 12″, 13″ are fastened to the outer tube 3. So that the three-arm open stone basket 10 opens and closes in the desired manner, a first wire section 11′, 12′, 13′ of each wire sling 11, 12, 13 is guided together with the second wire section 12″, 13″, 11″ of the respective neighboring wire sling 12, 13, 11 in a common envelope 14. The envelope 14 that enables a longer service life and, with a suitable color and material selection, a better visibility is not fastened to the outer tube 3 in the illustrated example. Such an attachment, e.g. by means of a shrink sleeve section, can however be provided indeed in order to prevent sliding of the envelopes 14. Such a guide envelope 14 is not required for other tools or closed stone baskets 10 (compare FIGS. 6 to 9).

[0069] The arrangement illustrated here in detail of the proximal wire ends at the inner tube and at the outer tube can be applied to other embodiments of the tool with a deviating number of wire slings. Important in this context is that of the two ends of each wire sling one is fastened to the inner tube and one to the outer tube, respectively, in order to be able to deform the wire slings for actuation of the tool by a relative displacement of the tube assembly.

[0070] In general, the possibilities for attachment of the proximal ends of the wire sections at the outer and the inner tube can depend on the material of the tubes wherein the wire sections are preferably of metal, particularly preferred of nitinol, so that they can be embodied with a pretension for the open position of the tool.

[0071] The outer tube at which the proximal ends of the second wire sections are fastened is of a plastic material so that the proximal ends of the second wire sections can be fused into the distal tube end when the plastic material is a meltable thermoplastic material. However, since the outer tube can be preferably manufactured of a heat-resistant plastic material such as polyimides, some of which are not meltable, the proximal ends of the second wire sections can be fastened by means of adhesive and/or an additional shrink hose section (not illustrated) to the outer tube.

[0072] In principle, the proximal ends of the first wire sections can be fastened in the same manner, i.e., by means of adhesive and/or an additional shrink hose section, to the inner tube which—in contrast to the outer tube—can comprise a fiber reinforcement as a bending protection of the laser fiber guided therein. For reducing the friction at the outer tube for improved sliding upon relative movement between the outer and the inner tube, the fiber reinforcement can be provided at least on the outer side with a friction reducing plastic coating. For this purpose, a plastic material with a reduced friction coefficient such as, for example, polytetrafluoroethylene or the like, can be used. Advantageously, in this context, the static friction is of the same magnitude as the slide friction so that the relative movement between outer and inner tube can be performed without jerking.

[0073] Further possibilities are available for connection of the proximal ends of the first wire sections to the inner tube due to the fiber reinforcement. For example, open fiber ends at the distal end of the inner tube can be connected by friction to the proximal ends of the first wire sections, i.e., by knotting, intertwining, interlocking etc. The fiber ends can be connected by material fusion to the first ends, for example, by gluing. When the fibers of the fiber reinforcement are at least partially of metal, welding or soldering for connecting the fiber ends to the proximal ends of the first wire section are conceivable also. When the metal of the reinforcement fibers is the same metal as it is provided for the wire slings, an integral connection between the fiber reinforcement and the proximal ends of the first wire sections can be present in that the first wire sections are formed of the metal fiber ends of the fiber textile reinforcement of the inner tube or at least of some of these metal fiber ends.

[0074] FIGS. 1 and 2 illustrate the actuation of the stone basket 10 at the handle 20 which comprises for this purpose a handle slide 21 which is axially slidable relative to the handle body 20′. The handle 20 comprises moreover a handle body attachment 26 and an axial end section (Tuohy-Borst adapter) 27 that adjoin at the proximal end of the grip body 20′ and of the attachment 26, respectively, and serve for supporting the inner tube 4 in a fixation sleeve 25 and for sealing the laser fiber 2 with a sealing lip 28. The laser fiber 2 extends coaxially through the entire catheter assembly and the handle 20 and out of the proximal axial end section 27 in order to be able to be connected to a laser light source (thulium laser—not illustrated).

[0075] As can be seen in the section illustration in FIG. 2, the attachment of the outer tube 3 at the handle slide 21 is realized by means of a connection sleeve 23 which surrounds a proximal end section of the outer sleeve 3 and is fastened, e.g. glued, thereto. The connection sleeve 23 is supported in a slide sleeve 22 which is connected to the handle slide 21. In this example, the slide sleeve 22 is guided additionally in a guide sleeve 24 that is arranged proximal to the slide sleeve 22 in the handle body 20′. Through this guide sleeve 24, the inner tube 4 extends to the fixation sleeve 25 in which a proximal end section of the inner tube 4 is fastened. The fixation sleeve 25 is supported in a handle body attachment 26 which adjoins axially the proximal end of the handle body 20′. Handle body 20′ and handle body attachment 26 can comprise corresponding thread sections for this. The fixation sleeve 25 is stationary in relation to the slidable outer tube 4, but supported with an overload protection. This is provided by a coil spring 30 that is contacted at its proximal end by the fixation sleeve 25 and whose distal end is supported at the annular shoulder 24′ which is formed by the proximal end of the guide sleeve 24. The inherent tension or a pretension of the spring 30 determines the force up to which the fixation sleeve 25 remains stationarily supported. In order to avoid damage of the stone basket 10 by pulling forces that are too great, e.g., when a very large captured concrement prevents a further closing of the basket 10 upon forward sliding of the handle slide 21, the pulling forces which are acting in this context on the inner tube 4 cause a compression of the spring 30 by means of the fixation sleeve 25, i.e., the inner tube 4 follows the movement of the outer tube 3 for relief of the wire slings.

[0076] In this context, the stone basket 10 in the illustration is in the open position. By movement of the handle slide 21 in distal direction, i.e., forwardly in the direction of the stone basket 10, the stone basket 10 deforms into the closed position by sliding of the outer tube 3 relative to the inner tube 4 with the wire sling ends respectively connected thereto.

[0077] In other embodiments, actuation variants deviating therefrom are however conceivable also.

[0078] In the handle body attachment 26 proximal to the fixation sleeve 25 in which the proximal end of the inner tube 4 is fastened, an insertion aid 29 is arranged in order to facilitate insertion of the laser fiber 2 into the inner tube 4 upon assembly. The insertion aid 29 comprises for this purpose at its proximal end a funnel-type opening that tapers toward the inner diameter of the inner tube 4. For fixation and sealing of the laser fiber 2, an axial end section 27 such as a Tuohy-Borst adapter is arranged and fastened, for example, by means of corresponding thread sections, at the proximal end of the handle body attachment 26. Fixation and sealing of the laser fiber 2 is achieved by a radial seal lip 28 whose opening diameter can be adjusted by rotation of a housing section of the end section 27.

[0079] The handle illustrated in FIGS. 1 and 2 is only exemplary. Deviations in design and modifications of functional details are possible within the claimed subject matter. Thus, alternatives to the handle slide as actuation element for sliding the outer tube, such as e.g. an adjusting wheel that by transmission means transmits the rotational movement in axial translation, are conceivable as well as variants in which the inner tube can be moved relative to the outer tube so that the elements for actuation and for stationary but overload-protected support must be realized correspondingly in reverse.

[0080] FIG. 5 shows in a schematic manner an embodiment of a handle 20 that permits a displacement of the laser fiber 2 independent of the actuation of a tool 10, such as opening and closing of a stone basket, so that the laser fiber 2 can be separately manipulated. For this purpose, the handle 20 comprises a second actuation element 40 that in the illustrated example is provided between the handle body attachment 26, in which the insertion aid 29 and the fixation sleeve 25 are present, and the axial end section 27 with the seal lip 28. For this purpose, a further handle section can be inserted for integration of the actuation element 40 that comprises a slide device or is connected thereto in order to axially slide the laser fiber 2. For this purpose, structures such as handle slide or adjusting wheel with transmission means are conceivable similar to those that are provided for displacement of the outer tube 4.

[0081] FIGS. 6 to 9 show alternative tools 10 of a medical instrument 1 while in FIGS. 1 to 4 an open stone basket 10 with a three-arm embodiment as a tool 10 of the medical instrument 1 is illustrated. This open three-arm basket that represents a particularly preferred embodiment combines the advantages of a conventional basket such as safe capture of stones and fragments with those of a grasper that enables a simple new positioning of stones and represents thus an optimal tool for the removal of stones. This stone basket 10 as well as the other tools 10 of FIGS. 6 to 9 can be imparted with a high permanent stability by a flat wire design of the wire slings because the flat wire design effects a higher radial force that ensures improved functionality.

[0082] In FIG. 6, a closed stone basket 10 with a captured stone (concrement) K is illustrated as tool 10. Since the optical waveguide 2 and the catheter assembly of inner tube 4 and outer tube 3 are coaxially arranged, the optical waveguide 2 ends exactly centrally or coaxially in the grasp tool 10 which significantly reduces the probability of hitting a tool structure when the object K that is grasped by the tool 10 is irradiated by a laser beam that is exiting from the optical waveguide 2. The stone basket 10 in FIG. 6 has a straight shape that imparts to the stone basket 10 an erection force as large as possible, with a cap-type tip 15 in which the wire sections 11′, 11″, 12′, 12″ are joined for forming the wire structure from essentially two symmetric wire slings in a region B opposite to the exit end 2′ of the optical waveguide 2. In this context, the first wire elements 11′, 12′ at the proximal ends 11a, 12a are connected to the inner tube 4 and the second wire elements 11″, 12″ are connected at the ends 11b, 12b to the outer tube 3.

[0083] FIG. 7 shows three further embodiments a), b), c) of a closed stone basket 10 wherein here the details of the attachment of the wire sling ends at the outer tube 3 and the inner tube (not illustrated) are not illustrated for the purpose of simplifying the drawing. The stone basket 10 in FIG. 7a) corresponds to the basket of FIG. 6 with the exception that it comprises a helical shape, i.e., that the wire sections 11′, 11″, 12′, 12″ do not extend straight to the tip 15 but have a winding course. The helical shape enables an easier capture of a stone.

[0084] As an alternative to an embodiment of four separate wire sections 11′, 11″, 12′, 12″, the wire slings of a stone basket 10 with tip 15 can be manufactured of a single wire. In this context, the slings are formed by three uniformly spaced-apart acutely angled bending locations in alternating directions of the single wire that thus divide it into four continuous wires sections 11′, 11″, 12′, 12″ of which two neighboring wire sections 11′, 11″, 12′, 12″, respectively, form one of the wire slings, respectively. In the arrangement of such a closed stone basket 10 of a single wire at the distal end of the catheter assembly, there are two possibilities. Either the first and third bending location are arranged in the region B that is positioned opposite the exit end 2′ of the optical waveguide 2 and connected to each other in the tip 15 so that the free wire ends of the single wire form proximal ends 11a, 12a of first wire sections 11′, 12′ or proximal ends 11b, 12b of second wire sections 11″, 12″ that are fastened at one of outer tube 3 and inner tube, wherein the second bending location forms the respective other proximal ends 11b, 12b of second wire sections 11′, 12′ or the proximal ends 11a, 12a of first wire sections 11′, 12′ that are fastened at the other one of outer tube 3 and inner tube. Or, alternatively, the first bending location can form the proximal ends 11a, 12a of the first wire sections 11′, 12′ and the third bending location the proximal ends 11b, 12b of the second wire sections 11″, 12″ (or, in reverse, the first bending location forms the proximal ends 11b, 12b of the second wire sections 11″, 12″ and the second bending location the proximal ends 11a, 12a of the first wire sections 11′, 12′) and be fastened respectively to the inner tube and the outer tube 3, while the free ends of the single wire and the second bending location in the region B that is positioned opposite the exit end 2′ of the optical waveguide 2 are connected in the tip 15.

[0085] FIGS. 7b) and 7c) show respectively a stone basket 10 without a tip that enables a guiding action gentle to tissue with the rounded connection region B. In the illustrated examples, the stone basket 10 is comprised of two wire slings 11, 12 with wire sections 11′, 11″ and 12′, 12″ that are connected in one piece, respectively, wherein the proximal ends 11a, 12a of the first wire sections 11′, 12′ are connected to the inner tube (not illustrated) and the proximal ends 11b, 12b of the second wire sections 11″, 12″ to the outer tube 3. The stone basket 10 in FIG. 7c) comprises in this context in connection region B a connection location or surface 16 in the form of a diamond with concavely rounded sides. This connection location 16 can provide an improved endoscopic visibility when suitably colored.

[0086] In deviation from the illustrated examples, baskets with tip can also be formed of two wire slings or more, and baskets without tip can be formed of four or more separate wire sections or a single wire. In further deviation from the illustrated examples, closed stone baskets can also comprise an asymmetric number of first and second wire sections whose proximal ends then correspondingly are arranged asymmetrically at the outer and inner tubes. In this manner, a stone basket comprised of four wire sections can be fastened with a first wire section to the inner tube and with the three other second wire sections to the outer tube, or in reverse. Furthermore, closed stone baskets can also be formed of an uneven number of wire sections. In the stone basket of three wire sections, e.g. a first wire section can be connected at the proximal end to the inner tube and the two other second wire sections to the outer tube, or, in reverse, two first wire sections to the inner tube and a second wire section to the outer tube. With increasing number of wire sections, the number of possible arrangement variants increases correspondingly and are therefore not explained here in detail but are easily apparent to a person of skill in the art.

[0087] FIG. 8 shows two examples a) and b) with alternative tools 10 as working tip of a medical instrument according to the invention. In this context, the tool 10 is comprised of a wire sling 11 whose first wire section 11′ is fastened at the proximal end 11a to the inner tube 4 and whose second wire section 11″ at the proximal end 11b to the outer tube 3 of the catheter assembly. Here also, the laser fiber 2 ends centrally in the space which is delimited by the wire sling 11 which in FIG. 8a) is substantially embodied as an areal oval. Not illustrated are polygonal sling forms such as e.g. hexagon slings. FIG. 8b) shows a sickle-shaped sling 11 which delimits a shell-shaped space in which the laser fiber 2 ends coaxially. The wire sling 11 can be formed of a one-piece wire with two continuous wire sections 11′, 11″ or of two wire sections 11′; 11″ connected to each other.

[0088] In FIG. 9, a situation of use of a medical instrument according to the invention with stone basket 10 is illustrated which has been opened through a working channel 101 of an insertion tube 100 of a ureteroscope, for example, at a location of use. In the illustrated example, the insertion tube 100 in addition comprises an illumination device 103 and a camera sensor 102 by means of which the user can observe the location of use. Due to the smaller dimension of the catheter assembly as a result of the employed thulium laser technology with the coaxially arranged optical waveguide 2 which can be embodied with an outer diameter (without buffering) of 150 μm to 200 μm (i.e., 130 μm to 180 μm core diameter and 10 μm cladding), the user has available more manipulation clearance in the working channel 101 and a maximum flushing flow for flushing can be obtained. In addition, the thulium laser technology enables an efficient lithotripsy at higher pulse rates. In relation to the laser power that is required for breaking up, theoretically laser fibers with even smaller diameters could be used, but then the stability and durability of the instrument suffers. And since already with laser fiber cross sections of 150 μm to 200 μm a very good flexibility of the instrument and a satisfactory flushing flow can be achieved, a further miniaturization of the fiber cross section of the optical waveguide for a minimal further increase of the flexibility represents no significant overall improvement because this would entail a significantly limited stability and durability.

[0089] In principle, the combined use of a stone basket with a laser lithotripter minimizes the stone retropulsion because the stone captured in the stone basket cannot yield upon impact of the laser pulse. Advantageously however, due to the coaxial arrangement that is now made possible by a miniaturized instrument, laser-induced damages at the wire slings are reduced because the laser pulse always impacts centrally on a captured concrement.

[0090] For producing a medical instrument according to the invention, first the catheter assembly of outer tube and inner tube, coaxially arranged thereto and relatively movable thereto, as well as the tool of a wire structure that is formed of at least two wire sections are provided. At least one proximal end of the wire sections of the wire structure is fastened to the distal end of the inner tube and at least one proximal end of the wire section of the wire structure to the distal end of the outer tube so that a relative movement between outer and inner tube effects opening and closing of the tool.

[0091] The proximal ends of the outer and inner tube are fastened with an actuation element in a suitable manner in a handle in order to be able to trigger the relative movement between the outer and the inner tube for opening and closing the tool. For this purpose, it is expedient that in the handle a proximal end section of the inner tube projects past a proximal end of the outer tube. In this context, for example, the proximal end section of the outer tube can be connected to the actuation element and the proximal end section of the inner tube can be supported stationarily in the handle so that the outer tube for actuation of the tool by means of the actuation element can be axially displaced in relation to the inner tube. The stationary support of the proximal end section of the inner tube can be embodied, as needed, for overload protection as a sprung support.

[0092] Only at the end, the optical waveguide, that is preferably used without buffering, so that first the buffering must be removed as needed, is coaxially inserted in and through the inner tube from its proximal end until the exit end of the optical waveguide at least closes off the distal end of the inner tube and thus can end coaxially in the space which is delimited by the tool. Since the proximal end of the inner tube is supported in the handle, it comprises at the proximal end a sealable opening for insertion of the optical waveguide. In addition, an insertion aid with a tapering insertion opening can be provided here in order to facilitate the threading action into the inner tube. In this context, for insertion of the optical waveguide for avoiding damages of the optical waveguide itself as well as of the inner and optionally outer tube, it is advantageous to position axially stretched the handle and the catheter assembly in order to facilitate the passing through action of the optical waveguide.

LIST OF REFERENCE CHARACTERS

[0093] 1 medical instrument [0094] 2, 2′ optical waveguide, exit end [0095] 3 outer tube [0096] 4 inner tube [0097] 10 tool, stone basket [0098] 11, 12, 13 wire sling [0099] 11a, 12a, 13a proximal end of the first wire section [0100] 11b, 12b, 13b proximal end of the second wire section [0101] 11′, 12′, 13′ first wire sections [0102] 11″, 12″, 13″ second wire sections [0103] 14 envelope [0104] 15 tip [0105] 16 connection location [0106] 20, 20′ handle, handle body [0107] 21 actuation element/handle slide [0108] 22 slide sleeve [0109] 23 connection sleeve [0110] 24 guide sleeve [0111] 24′ annular shoulder [0112] 25 fixation sleeve [0113] 26 handle body attachment [0114] 27 proximal axial end section/Tuohy-Borst adapter [0115] 28 seal lip [0116] 29 insertion aid for laser fiber [0117] 30 support device/spring [0118] 40 second actuation element [0119] 100 insertion tube [0120] 101 working channel [0121] 102 camera sensor [0122] 103 illumination [0123] B region opposite the exit end [0124] K concrement