Implantable Marker

Abstract

An implantable marker for marking an intracorporeal tissue region of an animal or human, including at least one strand produced from biocompatible material and which has a three-dimensional shape impressed during a shaping process. The strand adopts the three-dimensional shape after cessation of an external mechanical constraint that forced the strand to adopt a compacted three-dimensional shape. The three-dimensional shape impressed upon the strand comprises at least two fixed strand eyelets with each eyelet being formed by at least one helical winding of the strand and having at least one of shape and relative spatial position being different in the compacted three-dimensional shape forced upon them by the external mechanical constraint and the three-dimensional shape adopted after cessation of the mechanical constraint.

Claims

1-11. (canceled)

12. An implantable marker for marking an intracorporeal tissue region of an animal or human, comprising: at least one strand of a biocompatible material on which a three-dimensional shape is impressed during a shaping process, the at least one strand adopting the three-dimensional shape after cessation of an external mechanical constraint that forces the strand to adopt a compacted three-dimensional shape; and wherein the three-dimensional shape impressed upon the at least one strand comprises at least two fixed strand eyelets, each eyelet being formed by at least one helical winding of the strand with at least one of shape and relative spatial position being different for a compacted three-dimensional shape forced on each eyelet by the external mechanical constraint and the three-dimensional shape is assumed after cessation of the mechanical external constraint.

13. The implantable marker according to claim 12, wherein: at least two fixed strand eyelets are connected to each other via a strand therebetween.

14. The implantable marker according to claim 13, wherein: each strand is located and formed with the fixed strand eyelets, is connected via the strand, each strand is positioned without overlapping at least in the compacted three-dimensional shape imposed by the external mechanical constraint.

15. The implantable marker according to claim 12, wherein: at least three fixed strand eyelets are formed along the strand and are arranged in series along a virtual linear axis in the compacted three-dimensional shape imposed by the external mechanical constraint; and the at least three fixed strand eyelets, after cessation of the mechanical constraint causing the impressed three-dimensional shape, are positioned to be three-dimensionally different from being in series along a virtual linear axis when the mechanical constraint is applied.

16. The implantable marker according to claim 13, wherein: at least three fixed strand eyelets are formed along the strand and are arranged in series along a virtual linear axis in the compacted three-dimensional shape imposed by the external mechanical constraint; and the at least three fixed strand eyelets, after cessation of the mechanical constraint causing the impressed three-dimensional shape, are positioned to be three-dimensionally different from being in series along a virtual linear axis when the mechanical constraint is applied.

17. The implantable marker according to claim 14, wherein: at least three fixed strand eyelets are formed along the strand and are arranged in series along a virtual linear axis in the compacted three-dimensional shape imposed by the external mechanical constraint; and the at least three fixed strand eyelets, after cessation of the mechanical constraint causing the impressed three-dimensional shape, are positioned to be three-dimensionally different from being in series along a virtual linear axis when the mechanical constraint is applied.

18. The implantable marker according to claim 12, wherein: a winding direction of the at least one helical winding of each fixed strand eyelet is different between adjacent eyelets positioned along the strand.

19. The implantable marker according to claim 12, wherein: each fixed strand eyelet has an opening plane; the opening plane of at least one fixed strand eyelet is not oriented parallel to the eyelet opening plane of at least one other strand eyelet after cessation of the mechanical constraint, or the eyelet opening planes of all strand eyelets are parallel in the impressed three-dimensional shape after cessation of the mechanical constraint.

20. The implantable marker according to claim 13, wherein: each fixed strand eyelet having an opening plane; the eyelet opening plane of at least one fixed strand eyelet is not oriented parallel to the eyelet opening plane of the at least one other strand eyelet after cessation of the mechanical constraint in the impressed three-dimensional shape, or the eyelet opening planes of all strand eyelets are parallel in the impressed three-dimensional shape after cessation of the mechanical constraint.

21. The implantable marker according to claim 14, wherein: each fixed strand eyelet having an opening plane; the eyelet opening plane of at least one fixed strand eyelet is not oriented parallel to the eyelet opening plane of the at least one other strand eyelet after cessation of the mechanical constraint in the impressed three-dimensional shape, or the eyelet opening planes of all strand eyelets are parallel in the impressed three-dimensional shape after cessation of the mechanical constraint.

22. The implantable marker according to claim 15, wherein: each fixed strand eyelet having an opening plane; the eyelet opening plane of at least one fixed strand eyelet is not oriented parallel to the eyelet opening plane of the at least one other strand eyelet after cessation of the mechanical constraint in the impressed three-dimensional shape, or the eyelet opening planes of all strand eyelets are parallel in the impressed three-dimensional shape after cessation of the mechanical constraint.

23. The implantable marker according to claim 12, wherein: each strand includes a biocompatible material that reflects ultrasonic waves.

24. The implantable marker according to claim 13, wherein: each strand includes a biocompatible material that reflects ultrasonic waves.

25. The implantable marker according to claim 14, wherein: each strand includes a biocompatible material that reflects ultrasonic waves.

26. The implantable marker according to claim 15, wherein: each strand includes a biocompatible material that reflects ultrasonic waves.

27. The implantable marker according to claim 12, wherein: each strand has a strand surface including areas includes a structured surface that reflects ultrasonic waves.

28. The implantable marker according to claim 13, wherein: each strand has a strand surface including areas includes a structured surface that reflects ultrasonic waves.

29. The implantable marker according to claim 14, wherein: each strand has a strand surface including areas includes a structured surface that reflects ultrasonic waves.

30. An implantable marker according to claim 23, wherein: the strand of biocompatible material comprises at least one material with shape-memory properties.

31. The implantable marker according to claim 30, wherein: each strand of biocompatible material comprises a wire made of a metal shape-memory metal selected from the following group: NiTi (“Nitinol”), NiTiCu, CuZn, CuZnAl or CuAlNi.

32. The implantable marker according to claim 12, wherein: each strand has at least two fixed strand eyelets positioned to be a compacted three-dimensional shape imposed by the external mechanical constraint in a hollow cannula exerting the external mechanical constraint on the strand.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Without limiting the general idea of the invention, the invention is described below by way of exemplary embodiments with reference to the drawing. The figures show:

[0024] FIG. 1a is a first embodiment of an implantable marker formed in accordance with the invention in a compacted three-dimensional shape;

[0025] FIG. 1b, and c show a plan and side view of the implantable marker according to FIG. 1a with impressed three-dimensional shape;

[0026] FIG. 2a shows a second exemplary embodiment of an implantable marker in a compacted three-dimensional shape;

[0027] FIGS. 2b, c, and d show different viewing angles on the implantable marker according to FIG. 2a in the impressed three-dimensional shape; and

[0028] FIGS. 3a-c show different strand surface structures.

DETAILED DESCRIPTION OF THE INVENTION

[0029] FIGS. 1a-c illustrate a first exemplary embodiment of an implantable marker formed in accordance with the invention. FIGS. 1b and c show the marker 1 in plan and side view, in each case in its three-dimensionally impressed three-dimensional shape. The marker 1 is produced from a round wire 2, preferably made of nitinol (NiTi), and has two fixed strand or wire eyelets 3, 4 in its impressed three-dimensional shape. The wire eyelets 3, 4 are each produced by a single-layer helical winding along the wire made of nitinol. The winding direction of both wire eyelets 3, 4 is oriented in opposite directions.

[0030] For the purpose of intracorporeal location of the implantable marker 1, the marker 1 is transferred by an external mechanical constraint into the linearly stretched, compacted three-dimensional shape illustrated in FIG. 1a. For this purpose, the nitinol wire 2 is stretched under tensile force in the longitudinal direction of the wire from its impressed three-dimensional shape illustrated in FIGS. 1b and c and is inserted into a hollow cannula 5.

[0031] With the help of a stylet 6, the wire 2 in the compacted three-dimensional shape is pushed through the distal opening 7 of the hollow cannula 5. Immediately after the marker 1 has emerged through the distal opening 7 of the hollow cannula 5, the marker 1 assumes the impressed three-dimensional shape illustrated in FIGS. 1b and c. The two fixed wire eyelets 3, 4, which are integrally connected to each other by a wire portion 8, each have eyelet planes E1, E2 lying in the drawing plane. Of course, the eyelet planes E1, E2 associated with the fixed wire eyelets 3, 4 can also be inclined or rotated in relation to each other. For this purpose, a corresponding mechanical material-inherent pre-tension must be provided along the wire portion 8, by means of which pre-tension a twisting of both fixed wire eyelets 3, 4 relative to each other is initiated, which is represented in this respect by the arrow P1 illustrated in FIG. 1b. Alternatively to the above twisting or in combination with the twisting, a mechanically pre-programmed wire curvature can be introduced along the wire portion 8, which is straight in FIGS. 1b, c, as indicated by the arrow P2 which is in FIG. 1c.

[0032] The three-dimensional shape impressed on the implantable marker 1, shown in FIG. 1, enables easy and reliable detection with the aid of an ultrasound-based imaging method, regardless of the spatial orientation of the implanted marker 1 relative to the intracorporeal ultrasound wave field.

[0033] FIGS. 2a-d illustrate a preferred advanced embodiment for forming an implantable marker 1 according to the invention having an impressed three-dimensional shape shown from different viewing angles in FIGS. 2b-d.

[0034] In this case, the implantable marker 1 has five fixed strand or wire eyelets 9-13, each of which is produced integrally, preferably from a nitinol wire 2. From FIGS. 2b-d, which show the implantable marker 1 at different perspective viewing angles, it can be seen that the fixed wire eyelets 10 and 12 each provide more than one helical winding. The number of windings from which a fixed wire eyelet is made can be variably selected as desired. Also, the number of wire eyelets along the wire 2 as well as their distances and orientations to each other can be chosen arbitrarily.

[0035] FIG. 2a shows the compacted three-dimensional shape of the implantable marker 1, in which the fixed wire eyelets 9 to 13 are arranged linearly along a virtual linear axis 14 under external mechanical tensile constraint, so that they can be inserted inside a hollow cannula 5. As soon as the marker 1 in the compacted three-dimensional shape has been pushed distally out of the hollow cannula 5 with the aid of the stylet 6, the marker 1 abruptly, that is spontaneously, assumes the impressed three-dimensional shape illustrated in FIGS. 2b-d. The fixed wire eyelets 9-13 form a virtual linear axis 14 under external mechanical traction. In this case, the fixed wire eyelets 9-13 together with the wire portions 8 form a three-dimensionally determined structure or three-dimensional shape which, in interaction with an ultrasonic wave field, generates significant reflection signals which appear visually significant on an ultrasonic image. In addition, due to the abrupt transition from the compacted three-dimensional shape shown in FIG. 2a to the impressed three-dimensional shape illustrated in FIGS. 2b-d, the implantable marker 1 formed in accordance with the invention is able to enter into a close and mechanically stable connection with the biological tissue surrounding the marker 1, so that undesired migration of the implanted marker 1 within the tissue can be ruled out from the outset.

[0036] For the sake of completeness only, it should be noted that, in deviation from the impressed three-dimensional shape of the implantable marker 1 illustrated in FIGS. 2b-d, twists or curvatures may also be introduced along the wire portions 8 and shown in FIGS. 1b, c by the arrow representations P1, P2.

[0037] In order to improve the ultrasound reflectivity of the implantable marker 1 according to the invention, the surface 15 of the strand or wire 2 can be structured. Possible surface structurings of the strand or wire 2 are illustrated in FIGS. 3a-c. FIG. 3a shows groove-shaped impressions 17 extending along the strand or wire surface 15. In FIG. 3b, the strand surface 15 is provided with a multiplicity of local indentations 18 that provide increased ultrasonic reflectivity. FIG. 3c provides a grooved surface structuring 19 along the strand or wire surface 15.

[0038] The individual features of the individual exemplary embodiments may be combined as desired. The lengths of the wire portions 8 in FIGS. 2a to d, each with the same dimensions, can also be individually dimensioned without adversely affecting the ultrasonic wave reflectivity.

[0039] Although the wire eyelets, which can be seen in the plan view in FIG. 2b, project an equilateral triangle D and thus represent a mathematically defined or geometrically determined recognition pattern, which is particularly suitable for autonomous image evaluation.

[0040] The following design parameters of the three-dimensional shape impressed into the implant 1 can be selected as desired: [0041] diameter d of the wire eyelets, [0042] length L of the wire portions, [0043] angles α, β between the wire portions 8, as seen in FIGS. 2c, d, [0044] number of helical windings per wire eyelet, [0045] geometric shape of each wire eyelet: circular, elliptical, oval, with n angles, and [0046] winding direction of the helical windings.

LIST OF REFERENCE SIGNS

[0047] 1 implantable marker [0048] 2 strand or wire [0049] 3, 4 fixed eyelet [0050] 5 hollow cannula [0051] 6 stylet [0052] 7 distal opening [0053] 8 strand portion, wire portion [0054] 9-13 fixed eyelet [0055] 14 virtual linear axis [0056] 15 strand surface or wire surface [0057] 16 groove-shaped impression [0058] 17 local indentations [0059] 18 grooved surface structure [0060] D equilateral triangle [0061] d diameter of fixed eyelet [0062] L length of strand-wire portion [0063] α, β angle between the wire portions