TUBULAR INSTRUMENT WITH SELF-EXPANDING WIRE STRUCTURE

Abstract

A tubular instrument includes a tubular assembly having first and second handling tubes extending from a proximal operating area to a distal functional area, a radially self-expanding wire structure, and a holding device. The first and second handling tubes are rotatable relative to each other. A control interface is provided at the proximal operating area for the relative rotational motion actuation of the first and second handling tubes. The holding device includes a first connecting unit and a second connecting unit. The first connecting unit includes a first filament connecting unit having a first connecting filament fixed to a first structural connection interface of the wire structure and to a tube connection interface of the first handling tube and extends therebetween with a radial directional component, and which winds onto or unwinds from the first handling tube upon rotation of the first and second handling tubes.

Claims

1. A tubular instrument, in particular a medical catheter instrument, comprising: a tubular assembly comprising first and second handling tubes extending from a proximal operating area to a distal functional area; a radially self-expanding wire structure; and a holding device adapted to hold the radially self-expanding wire structure at the distal functional area of the tubular assembly, wherein the first and second handling tubes are arranged to be relatively rotatable with respect to each other, a control interface is provided at the proximal operating area for the relative rotational motion actuation of the first and second handling tubes, and the holding device comprises a first connecting unit connecting the wire structure to the first handling tube, and a second connecting unit connecting the wire structure to the second handling tube, wherein the first connecting unit includes a first filament connecting unit having at least one first connecting filament which is fixed, on the one hand, to a first structural connection interface of the wire structure and, on the other hand, to a tube connection interface of the first handling tube and extends therebetween with a radial directional component and which, upon a relative rotation of the first and second handling tubes, winds onto or unwinds from the first handling tube in dependence on the direction of rotation.

2. The medical catheter instrument according to claim 1, wherein the first filament connecting unit comprises a plurality of first connecting filaments, each of which is fixed on the one hand to the first structure connection interface of the wire structure and on the other hand to the tube connection interface of the first handling tube and extends therebetween with a radial directional component and winds onto or unwinds from the first handling tube upon relative rotation of the first and second handling tubes in accordance with the direction of rotation.

3. The medical catheter instrument according to claim 2, wherein the first structural connection interface comprises a plurality of first filament attachment points distributed in a circumferential direction of the wire structure and to which the first connecting filaments are attached.

4. The medical catheter instrument according to claim 1, wherein the first and second handling tubes are arranged for relative movement with respect to each other in the axial direction parallel to the longitudinal axis of the tube.

5. The medical catheter instrument according to claim 1, wherein the tube connection interface of the first handling tube comprises a filament holding element which is arranged on the first handling tube in a rotationally fixed and axially movable manner and on which the at least one first connecting filament is fixed.

6. The medical catheter instrument according to claim 1, wherein the tube connection interface of the first handling tube comprises a filament holding sleeve arranged non-rotatably on the first handling tube, on which the at least one first connecting filament is fixed.

7. The medical catheter instrument according to claim 1, wherein the second connecting unit includes a second filament connecting unit having at least one second connecting filament fixed, on the one hand, to a second structural connection interface of the wire structure axially spaced from the first structural connection interface and, on the other hand, to a tube connection interface of the second handling tube and extending therebetween with a radial directional component and which, upon a relative rotation of the first and second handling tubes, winds onto or unwinds from the second handling tube in dependence on the direction of rotation.

8. The medical catheter instrument according to claim 7, wherein the second filament connecting unit comprises a plurality of second connecting filaments, each of which is fixed on the one hand to the second structural connection interface of the wire structure and on the other hand to the tube connection interface of the second handling tube and extends therebetween with a radial directional component and winds onto or unwinds from the second handling tube upon relative rotation of the first and second handling tubes in accordance with the direction of rotation.

9. The medical catheter instrument according to claim 8, wherein the second structural connection interface comprises a plurality of second filament attachment points distributed in a circumferential direction of the wire structure and to which the second connecting filaments are attached.

10. The medical catheter instrument according to claim 6, wherein the tube connection interface of the second handling tube comprises a second filament holding element which is arranged on the second handling tube in a rotationally fixed and axially movable manner and on which the at least one second connecting filament is held.

11. The medical catheter instrument according to claim 6, wherein the tube connection interface of the second handling tube comprises a second filament holding sleeve which is arranged on the second handling tube in a rotationally fixed manner and on which the at least one second connecting filament is held.

12. The medical catheter instrument according to claim 1, wherein the control interface is set up for counter-rotational motion actuation of the first and second handling tubes at pre-definable rotational speeds or filament winding rates.

13. The medical catheter instrument according to claim 1, wherein the control interface comprises a gearbox for actuating the first and second handling tubes in opposite rotational directions.

14. The medical catheter instrument according to claim 7, wherein the holding device comprises at least a third connecting unit comprising a third filament connecting unit which includes at least a third connecting filament which is fixed, on the one hand, to a third structural connection interface of the wire structure axially spaced from the other structural connection interface or interfaces and, on the other hand, to a further structural connection interface of the wire structure axially spaced from the other tube connection interfaces of the first handling tube or of the second handling tube or of a third handling tube of the tubular assembly axially spaced apart from the other tube connection interfaces and extends therebetween with a radial directional component and which, in the event of a relative rotation of the handling tubes, winds onto or unwinds from the relevant handling tube as a function of the direction of rotation.

Description

[0046] Advantageous embodiments of the invention are shown in the drawings. These and other embodiments of the invention are described in more detail below. The figures show the following:

[0047] FIG. 1 is a schematic side view of a tubular instrument,

[0048] FIG. 2 is a schematic side view of a distal functional area of the tubular instrument of FIG. 1 with a radially self-expanding wire structure held thereto in an expanded state,

[0049] FIG. 3 is a sectional longitudinal view of a tubular assembly of the tubular instrument of FIG. 1 in a region III of FIG. 1,

[0050] FIG. 4 is a sectional longitudinal view of a region IV of FIG. 2 including a tube connection interface of a first retaining tube of the tubular assembly,

[0051] FIG. 5 is a sectional oblique frontal view of an area of the tubular assembly with the tube connection interface of the first handling tube,

[0052] FIG. 6 is a sectional oblique rear view to the tube connection interface of the first handling tube,

[0053] FIG. 7 is the side view of FIG. 2 with the wire structure in a radially retracted state,

[0054] FIG. 8 is a detailed view of a region VIII in FIG. 7,

[0055] FIG. 9 is a side view according to FIG. 2 for a variant of the tubular instrument with more than two structural connection interfaces of the wire structure, and

[0056] FIG. 10 is the view of FIG. 7 for the tubular instrument variant of FIG. 9.

[0057] The tubular instrument shown in the figures in various embodiments and views includes a tubular assembly 1 comprising a first handling tube 2 and a second handling tube 3, a radially self-expanding wire structure 6, and a holding device 7. The two handling tubes 2, 3 extend from a proximal operating area 4 to a distal functional area 5, as schematically shown in FIG. 1.

[0058] In the examples shown, the handling tubes 2, 3 are arranged coaxially, i.e., their longitudinal axes LR.sub.1 and LR.sub.2 respectively coincide to form a common longitudinal axis L.sub.R of the tubular assembly 1. In alternative embodiments, they are arranged with parallel offset longitudinal axes LR.sub.1, LR.sub.2 nested or adjacent to each other.

[0059] The tubular assembly 1 preferably has a desired flexibility, i.e., bendability, for which purpose its handling tubes, such as the first and second handling tubes 2, 3 in the examples shown, are made of a corresponding flexible tube material capable of bending. The tubular instrument may be, for example, a medical catheter instrument, such as one for minimally invasive implantation of artificial heart valves or vascular stents, in which case the handling tubes 2, 3 may be made of any flexible tube material known per se to the person skilled in the art for this application. In alternative embodiments, this can be a tubular instrument usable in pipeline or piping applications.

[0060] The first and second handling tubes 2, 3 of the tubular assembly 1 are arranged to be relatively rotatable with respect to each other. In particular, in the examples shown, they can be changed in their relative rotational position with respect to the common longitudinal axis of the tube L.sub.R. At the proximal operating area 4, the tubular instrument has a control interface 8 for relative rotational motion actuation of the first and second handling tubes 2, 3. The control interface 8 can be of any configuration known to the person skilled in the art for carrying out the operating functions required and explained herein and is therefore only shown schematically in FIG. 1. The two handling tubes 2, 3 and the control interface 8 are configured, as required, so that only the first or only the second or both handling tubes 2, 3 is/are actively rotated, preferably in opposite directions, around the respective longitudinal axis LR.sub.1, LR.sub.2 or the common longitudinal axis L.sub.R in order to achieve the desired relative rotation.

[0061] In the exemplary embodiments shown, the wire structure 6 has a cylindrical, wire mesh-like shape, such as is suitable for applications in artificial heart valves and vascular stents. It goes without saying that for other applications, the wire structure (6) may have a different shape adapted to its intended use.

[0062] Depending on the application, the wire material used to build the wire structure 6 can be, for example, a shape memory metallic alloy material or another elastic metal or plastic material. The wire structure 6 can be cut in one piece from a tube material by means of laser cutting, as is known for stent structures per se, for example, or alternatively be assembled from several prefabricated individual parts.

[0063] The holding device 7 is configured to hold the radially self-expanding wire structure 6 on the distal functional area 5 of the tubular assembly 1. To this end, the holding device 7 comprises a first connecting unit 9.sub.1 connecting the wire structure 6 to the first handling tube 2, and a second connecting unit 9.sub.2 connecting the wire structure 6 to the second handling tube 3.

[0064] The first connecting unit 9.sub.1 contains a first filament connecting unit 10 with at least one first connecting filament 10.sub.1, which is fixed on the one hand at a first structural connection interface 6a of the wire structure 6 and on the other hand at a tube connection interface 11 of the first handling tube 2. For applications where the wire structure 6 is to remain in a positioned location of use, the at least one first connecting filament 10.sub.1 is preferably fixed by a detachable connection at the first structure connection interface 6a of the wire structure 6. Between the first structural connection interface 6a of the wire structure 6 and the tube connection interface 11 of the first handling tube 2, the first connecting filament 10.sub.1 extends with a radial directional component R.sub.R1, wherein it optionally also extends with an axial directional component R.sub.A1, as illustrated in FIG. 2, and/or a circumferential directional component.

[0065] During a relative rotation of the first and the second handling tube 2, 3 around the respective longitudinal axis LR.sub.1, LR.sub.2 or the common longitudinal axis L.sub.R respectively, the first connecting filament 10.sub.1 winds onto or off the first handling tube 2 depending on the direction in which the first handling tube 2 rotates relative to the second handling tube 3, i.e. clockwise or counterclockwise.

[0066] Since the at least one first connecting filament 10.sub.1 extends between the wire structure 6 and the first handling tube 2 with a said radial directional component R.sub.R1, its winding onto the first handling tube 2 has the effect of shortening it radially in the process, as a result of which it pulls the wire structure 6 radially inwards at the relevant first structural connection interface 6a.

[0067] This makes it possible for the user to radially retract the wire structure 6 from an expanded state, e.g. according to FIGS. 2 and 9, into the retracted state, e.g. according to FIGS. 7 and 10, respectively, by relative rotation of the handling tubes 2, 3 in the corresponding direction of rotation. In this case, the state according to FIGS. 2 and 9, respectively, need not necessarily be a fully expanded state of the wire structure 6, and the state according to FIGS. 7 and 10, respectively, need not necessarily be a fully retracted state thereof. In this respect, the wire structure 6 can be retracted this way, by an operating action of the user at the proximal end region 4 of the tubular instrument, from a completely or partially expanded state, into which it automatically expands on account of its radially self-expanding characteristic, for example until it comes to bear against radially surrounding material, into a state which, in contrast, is radially retracted to a certain extent.

[0068] This allows the user to easily reposition the wire structure 6 remotely in the event that it has expanded in an incorrect position. Once the radially retracted wire structure 6 has been repositioned, for example by axially displacing and/or rotating the tubular assembly 1 and thus also the wire structure 6, the user can enable the automatic radial expansion of the wire structure again by performing a relative rotation of the two handling tubes 2, 3 in the opposite direction to the previous one, as a result of which the at least one connecting filament 10.sub.1 unwinds from the first handling tube 2 again and releases the radial expansion of the wire structure 6. Once the desired exact position of the wire structure 6 has been achieved, its connection to the tubular assembly 1 may be released, after which the tubular assembly 1 may be withdrawn from the location of use of the wire structure. Alternatively, if the wire structure 6 serves merely as a transport medium or carrier for depositing another object or substance at the relevant location of use, it may again be retracted radially by relative rotation of the handling tubes 2, 3 and then withdrawn from the location of use together with the tubular assembly 1.

[0069] In advantageous embodiments, as in the examples shown, the first filament connecting unit 10 includes a plurality of first connecting filaments 10.sub.1, 10.sub.2, etc., each of which is fixed, on the one hand, to the first structural connection interface 6a of the wire structure 6 and, on the other hand, to the tube connection interface 11 of the first handling tube 2 and extends therebetween with a radial directional component, wherein the radial directional components for the different connecting filaments 10.sub.1, 10.sub.2, etc., may be the same size or alternatively different. Each of the first connecting filaments 10.sub.1, 10.sub.2, etc., winds onto or unwinds from the first handling tube 2 during said relative rotation of the first and second handling tubes 2, 3 depending on the rotational direction of said relative rotation, i.e., during a certain relative rotation of the two handling tubes 2, 3 all first connecting filaments 10.sub.1, 10.sub.2, etc, are either wound onto the first handling tube 2 or unwound therefrom. The presence of the plurality of first connecting filaments 10.sub.1, 10.sub.2, etc. may be conducive to a uniform radial retraction of the wire structure 6 around the circumference thereof.

[0070] In some embodiments, as in the examples shown, the first structural connection interface 6a of the wire structure 6 includes a plurality of first filament attachment points 12.sub.1, 12.sub.2, etc., arranged in a circumferential direction of the wire structure 6 in a distributed manner and to which the first connecting filaments 10.sub.1, 10.sub.2, etc., are attached. This measure is conducive to a uniform radial retraction of the wire structure 6 along its circumference, in that the retraction force acts via the first connecting filaments 10.sub.1, 10.sub.2, etc., on the filament attachment points 12.sub.1, 12.sub.2, etc., distributed along the circumference of the wire structure 6. In this case, the number of first filament attachment points 12.sub.1, 12.sub.2, etc., may be equal to or less than the number of first connecting filaments 10.sub.1, 10.sub.2, etc. In the latter case, at least two first connecting filaments are fixed together at a same first filaments attachment point.

[0071] In some embodiments, as in the examples shown, the first and second handling tubes 2, 3 are arranged to move relative to each other in the axial direction, i.e. parallel to the longitudinal tube axis L.sub.R. This allows the tubular assembly 1 to yield to or accommodate an axial change in length of the wire structure 6 in appropriate embodiments.

[0072] This can be seen, for example, from a comparative view of FIGS. 2 and 7 in that, starting from the expanded state of the wire structure 6 according to FIG. 2, when the wire structure 6 is radially contracted into the retracted state according to FIG. 7, the second handling tube 3 moves axially out of the first handling tube 3 to a certain extent.

[0073] In some embodiments of the tubular instrument, the tubular connection interface 11 of the first handling tube 2 has, as in the examples shown, a filament holding sleeve 14 arranged non-rotatably on the first handling tube 2. That is, when the first handling tube 2 is rotated, the filament holding sleeve 14 rotates therewith. The at least one first connecting filament 10.sub.1 is fixed onto the filament holding sleeve 14. Specifically, in the examples shown, the plurality of first connecting filaments 10.sub.1, 10.sub.2, etc., are held to the filament holding sleeve 14. In the examples shown, this is realized in that the filament holding sleeve 14 is provided with a plurality of circumferentially distributed axial bores 14a, as can be seen in FIGS. 4 and 5 and in FIG. 6 reproduced in a partially transparent representation for this purpose, and a respective filament piece coming from the first structural connection interface 6a of the wire structure 6 is looped through one of the bores 14a in the proximal direction and looped back again while being deflected through an adjacent bore 14a in the distal direction and returned to the first structural connection interface 6a of the wire structure 6. This type of connecting filament attachment to the tube connection interface 11 of the first handling tube 2 is shown in FIGS. 4 to 6 as an example for two pieces of filament for providing the connecting filaments 10.sub.1 and 10.sub.2 or 10.sub.5 and 10.sub.6, respectively. Consequently, in this case, at least two of the first connecting filaments 10.sub.1, 10.sub.2, etc., are formed by a single piece of filament held on the filament holding sleeve 14 by the deflected double looping through. As required, the piece of filament is fixed at the first structural connection interface 6a of the wire structure 6 or at its filament attachment points 12.sub.1. 12.sub.2, etc., with a respective filament end, e.g., by means of a detachable or non-detachable knot, or also looped through there in a deflecting manner and continued. The filament holding sleeve 14, for example, together with the first connecting filaments 10.sub.1, 10.sub.2, etc., held thereon, can be slid onto or otherwise positioned against the first handling tube 2 and subsequently fixed thereto in a releasable or non-releasable manner.

[0074] Alternatively, the attachment of the filament holding sleeve 14 to the first handling tube 2 may take place before the attachment of the first connecting filament 10.sub.1, 10.sub.2, etc., to the filament holding sleeve 14.

[0075] In some embodiments, as in the examples shown, the second connecting unit 9.sub.2 comprises a second filament connecting unit 15 having at least one second connecting filament 15.sub.1 fixed, on the one hand, to a second structural connection interface 6b of the wire structure 6 axially spaced from the first structural connection interface 6a and, on the other hand, to a tube connection interface 16 of the second handling tube 3. Analogous to the case of the at least one first connecting filament 10.sub.1, the at least one second connecting filament 15.sub.1 again extends with a radial directional component R.sub.R2 and optionally with an axial directional component R.sub.A2 and/or a circumferential directional component, as illustrated in FIG. 2, and winds onto or off the second handling tube 3 upon relative rotation of the first and second handling tubes 2, 3 depending on the direction of rotation.

[0076] In the examples shown, to prevent this winding and unwinding of the at least one second connecting filament 15.sub.1 onto and from the second handling tube 3 from being obstructed by the surrounding first handling tube 2, the second handling tube 3 extends distally forward beyond a distal end 2a of the first handling tube 2, wherein the second structural connection interface 6b of the wire structure 6 lies distally in front of the first structural connection interface 6a at an axial distance, and the tube connection interface 16 of the second handling tube 3 is arranged in the region of the second handling tube 3 lying distally in front of the distal end 2a of the first handling tube 2.

[0077] Consequently, in this configuration, the second connecting unit 9.sub.2 corresponds in its function to that of the first connecting unit 9i. The wire structure 6 is radially retracted at its second structural connection interface 6b by winding the at least one second connecting filament 15.sub.1 onto the second handling tube 3. Unwinding the second connecting filament 15.sub.1 from the second handling tube 3 releases the self-expanding function for the wire structure 6 at its second structural connection interface 6b.

[0078] The optional axial directional component R.sub.A1, R.sub.A2 of the connecting filaments 10.sub.1, 10.sub.2, etc., 15.sub.1, 15.sub.2, etc., can influence how the connecting filaments 10.sub.1, 10.sub.2, etc., 15.sub.1, 15.sub.2, etc., with their successive windings wind onto the respective handling tube 2, 3. In the examples shown, the respective connecting filament 10.sub.1, 10.sub.2, etc., 15.sub.1, 15.sub.2, etc., is wound helically in such a way that its windings follow one another on the handling tube 2, 3 in a single layer with axial spacing, or alternatively without axial spacing, as is schematically illustrated in FIGS. 7 and 10 and in FIG. 8 for the two connecting filaments 10.sub.1 and 10.sub.6 in more detail. Alternatively, the connecting filament windings on the relevant handling tube 2, 3 may be radially superimposed, e.g., if the relevant connecting filament extends without the axial directional component R.sub.A1, R.sub.A2 or with a correspondingly small axial directional component R.sub.A1, R.sub.A2.

[0079] In some embodiments, as in the examples shown, the second filament connecting unit 15 has a plurality of second connecting filaments 15.sub.1, 15.sub.2, etc., each of which is fixed on the one hand to the second structural connection interface 6b of the wire structure 6 and on the other hand to the tube connection interface 16 of the second handling tube 3 and extends therebetween with said radial directional component and winds onto or unwinds from the second handling tube 3 in accordance with the direction of rotation upon relative rotation of the two handling tubes 2, 3. In this case, the second filament connecting unit 15 is designed analogously to the design of the first filament connecting unit 10 with the plurality of first connecting filaments 10.sub.1, 10.sub.2, etc., and accordingly has analogous properties and functions, including the advantages mentioned in this regard above with respect to uniform radial retracting of the wire structure 6 over its circumference.

[0080] In some implementations, the second structural connection interface 6b of the wire structure 6 has, as in the examples shown, a plurality of second filament attachment points 17.sub.1, 17.sub.2, etc., distributed in a circumferential direction of the wire structure 6 and to which the second connecting filaments 15.sub.1, 15.sub.2, etc., are fixed. As required, the second connecting filaments 15.sub.1, 15.sub.2, etc., are also fixed at the second filament attachment points 17.sub.1, 17.sub.2, etc., detachably or non-detachably.

[0081] In this embodiment, the second structural connection interface 6b corresponds in its properties and functions to the first structural connection interface 6a of the wire structure 6 in its embodiment with the plurality of first filament attachment points 12.sub.1, 12.sub.2, etc. This also applies in particular with regard to the advantages mentioned for this purpose above with respect to uniform radial retraction of the wire structure 6 over its circumference.

[0082] In some embodiments, as in the examples shown, the tube connection interface 16 of the second handling tube 3 comprises a second filament holding sleeve 19 arranged non-rotatably on the second handling tube 3, on which the at least one second connecting filament 15.sub.1 is retained. In this embodiment, the tube connection interface 16 of the second handling tube 3 consequently corresponds in its functions and properties to the tube connection interface 11 of the first handling tube 2 explained above in the embodiment with the filament holding sleeve. This also applies to the optional possibility that the second filament holding sleeve 19 is provided with a plurality of axial bores, through which one or more filament pieces can be looped with deflection, in order to provide the second connecting filaments 15.sub.1, 15.sub.2, etc., as explained above for the analogous filaments looping through at the first filaments holding sleeve 14. And analogous to the first filament holding sleeve 14, the second filament holding sleeve 19, for example, together with the second connecting filaments 15.sub.1, 15.sub.2, etc., held thereon, can be slid onto or otherwise placed against the second handling tube 3 and subsequently fixed thereto in a detachable or non-detachable manner. Alternatively, the attachment of the second filament holding sleeve 19 to the second handling tube 3 can take place prior to the attachment of the second connecting filaments 15.sub.1, 15.sub.2, etc., to the second filament holding sleeve 19.

[0083] In some embodiments of the tubular instrument, the control interface 8 is set up for counter-rotational motion actuation of the first and second handling tubes 2, 3 at pre-definable rotational speeds and/or filament winding rates. For this purpose, the control interface 8 can, for example, be equipped with a suitable operating control 21, as illustrated in FIG. 1 for the embodiment of the tubular instrument there. The operating control 21 is optionally designed as an automated control system comprising, among other things, a motorized drive, or as a manual control system.

[0084] In some embodiments of the tubular instrument, the control interface comprises a gearbox 20 for counter-rotational motion actuation of the first and second handling tubes 2, 3, as also shown in FIG. 1 for the instrument embodiment there. By means of an appropriate design of the gearbox 20, a respective desired type of relative rotation of the two handling tubes 2, 3 can be specified or set, e.g. active rotation of both tubes 2, 3 in opposite rotation direction with the same or different rotational speeds and/or filament winding rates. This makes it possible to specify a desired time sequence for the radial retraction movement of the wire structure 6.

[0085] In some embodiments, as in the embodiment example of FIGS. 9 and 10, the holding device 7 comprises at least one third connecting unit 9.sub.3 having a third filament connecting unit 22 which includes at least one third connecting filament 22.sub.1 that is fixed, on the one hand, to a third structural connecting interface 6c of the wire structure 6 axially spaced from the other structural connecting interface(s) 6a, 6b and, on the other hand, to a further tubular connecting interface 23 axially spaced from the other tube connection interfaces 11, 16 and extending therebetween with a radial directional component R.sub.R3 and optionally an axial directional component R.sub.A3. In this case, the further tube connection interface 23 can be located on the first handling tube 2 or on the second handling tube 3 or on a further, third handling tube of the tubular assembly 1, depending on the application, whereby it winds onto or unwinds from the handling tube in question depending on the rotational direction during a relative rotation of the handling tubes involved.

[0086] In the embodiment example of FIGS. 9 and 10, in addition to the third connecting unit 9.sub.3 comprising the third filament connecting unit 22, a fourth connecting unit 9.sub.4 comprising a fourth filament connecting unit 24 including at least a fourth connecting filament 24.sub.1 is provided, wherein both further filament connecting units 22, 24 in this example each include a plurality of third connecting filaments 22.sub.1, 22.sub.2, etc., and fourth connecting filaments 24.sub.1, 24.sub.2, etc., respectively. The third connecting filaments 22.sub.1, 22.sub.2, etc., are fixed to the third structural connection interface 6c of the wire structure 6, again at a plurality of associated third filament attachment points 25.sub.1, 25.sub.2, etc., and the fourth connecting filaments 24.sub.1, 24.sub.2, etc., are fixed to a fourth structural connection interface 6d of the wire structure 6, again at a plurality of associated filament attachment points 26.sub.1, 26.sub.2, etc., as explained for the first and second connecting units 9.sub.1, 9.sub.2 and their filament connecting units 10, 15.

[0087] In other words, the four connecting units 9.sub.1 to 9.sub.4 may be of the same design among themselves, but in alternative embodiments they may be of different designs. In the embodiment example of FIGS. 9 and 10, the tube connection interface 23, at which the third connecting filaments 22.sub.1, 22.sub.2 are fixed, is located at the first handling tube 2, and the fourth connecting filaments 24.sub.1, 24.sub.2, etc., are fixed at another tube connection interface 26, which is located at the second handling tube 3.

[0088] In the embodiment example of FIGS. 9 and 10, the two additional tube connection interfaces 23, 26 are each formed by a further filament holding sleeve in the same way as the two other tube connection interfaces 11, 16. If an axial evasive movement is desired between the tube connection interfaces 11 and 23 or 16 and 26 belonging to the same handling tube 2 or 3 in each case, in order to absorb an axial change in length of the wire structure 6 during radial retraction, at least one of these respective two tube connection interfaces 11, 23 or 16, 26 may be designed (as an alternative or in addition to the embodiment as a filament holding sleeve) as a filament holding element 18 which is arranged on the associated handling tube 2, 3 in a rotationally fixed and axially movable manner and to which the connecting filaments concerned are attached, as is indicated in the example in FIGS. 9 and 10 as an example for the two additional tube connection interfaces 23, 26. The axially movable connection of the respective filament holding element 18 to the associated handling tube 2, 3 can be realized in any conventional manner, e.g., by an axial slotted guide system with an axial groove on one part and a corresponding link cam engaging therein on the other part.

[0089] In other embodiments, no axially movable connection of the tube connection interfaces 11, 16, 23, 26 to the respective handling tube 2, 3 and/or no axial movability of the handling tubes 2, 3 relative to one another is provided, which is possible in particular for applications in which the wire structure does not change in its axial length during radial retraction in the region of its structure connection interfaces or, in any case, does not require such an axial length change.

[0090] FIGS. 7 and 10 illustrate, for the two examples in question, the winding motion for radially retracting the wire structure 6 from its expanded state as displayed in FIGS. 2 and 9, respectively, by actively rotating the first handling tube 2 counterclockwise as symbolized by a rotary arrow D1 and actively rotating the second handling tube 3 clockwise as symbolized by a rotary arrow D2. As a result of this counterclockwise, active relative rotation of the two handling tubes 2, 3 with respect to each other, the first connecting filament(s) 10.sub.1, 10.sub.2, etc., wind onto the first handling tube 2, and the second connecting filament(s) 15.sub.1, 15.sub.2, etc., wind onto the second handling tube 3, causing the wire structure 6 to be radially contracted via its two axially spaced structural connection interfaces 6a, 6b. In the example of FIGS. 9 and 10, the third connecting filament(s) 22.sub.1, 22.sub.2, etc., additionally wind onto the first handling tube 2, and the fourth connecting filament(s) 24.sub.1, 24.sub.2, etc., wind onto the second handling tube 3.

[0091] Preferably, the same rotational amplitudes or rotational speeds or the same filament winding rates are selected for the active rotation of the two handling tubes 2, 3 in opposite directions, i.e. the first handling tube 2 is rotated by the same angle in one direction as the second handling tube 3 in the opposite direction. As a result, the wire structure 6 as a whole remains essentially stationary in its rotational position, i.e. it is drawn in radially without rotating in a noticeable manner. This is particularly convenient for many applications, e.g., it can minimize any tissue damage when the wire structure 6 in an application for an artificial heart valve or vascular stent is to be detached from the surrounding tissue after misplacement for repositioning. In addition, it is generally advantageous if the handling tubes 2, 3 are rotated in such a way that all connecting filaments wind onto the respective handling tube 2, 3 with essentially the same filament length per unit of time. This allows the wire structure 6 to be radially retracted at virtually the same radial retraction speed at all of its structural connection interfaces, and thus relatively uniformly over its axial extent.

[0092] As the embodiments shown and the other embodiments explained above make clear, the invention provides, in a highly advantageous manner, a tubular instrument having a self-expanding wire structure that permits repositioning of the wire structure, if necessary, when it is in an expanded, misplaced state, without damaging surrounding material to which it has bonded by the independent radial expansion. The tubular instrument according to the invention is particularly suitable for medical applications in endoscopy technology, e.g. as a medical catheter instrument for minimally invasive implantation of prosthetic heart valve and vascular stents, but can also be used for non-medical applications in suitable embodiments.