Marking device and implantation system

Abstract

Marking device (100) for implantation into a tissue (260), having a support structure (102) which is formed by at least one elastic metal wire, is compressible and is self-expanding and which, in an expanded state, encompasses an interior space (104), characterized in that the marking device (100) is designed to transform itself on its own from a compressed state into an expanded state, even against a tissue pressure prevailing at a tissue site to be marked, and the marking device (100) in the expanded state has a hollow, approximately spherical shape.

Claims

1. A marking device for implantation into a tissue, comprising: a support structure configured to transition between a compressed state and an expanded state, the support structure being formed from at least one elastic metal wire, the at least one elastic metal wire comprising a plurality of overlapping wire sections, wherein in the expanded state, the support structure has a rounded shape encompassing an interior space.

2. The marking device according to claim 1, wherein the support structure is woven, braided, wound or knitted.

3. The marking device according to claim 1, wherein all wire ends of the support structure are located within the interior space of the support structure.

4. The marking device according to claim 1, wherein a diameter of the at least one elastic metal wire is less than about 0.5 mm.

5. The marking device according to claim 1, wherein a diameter of the support structure in the expanded state is less than about 8 mm.

6. The marking device according to claim 1, wherein a diameter of the support structure in the compressed state is less than about 3 mm.

7. The marking device according to claim 1, wherein the at least one elastic metal wire comprises nitinol.

8. The marking device according to claim 1, further comprising, at least one a fastener for fixing the support structure in the tissue.

9. The marking device according to claim 8, wherein the at least one elastic metal wire includes a free end configured to anchor the marking device in the tissue.

10. The marking device according to claim 1, wherein the interior space contains hydrogel, polymer foam or surgical suture material.

11. The marking device according to claim 1, wherein the marking device has a membrane which is in contact with the support structure.

12. The marking device according to claim 1, wherein the interior space is surrounded by a material layer.

13. The marking device according to claim 1, wherein, in the expanded state, the support structure has a hollow, ellipsoid shape, and wherein a diameter of the marking device in the expanded state, viewed in a radial direction of a cannula implanting the marking device, is larger than a length of the marking device.

14. The marking device according to claim 1, wherein the marking device further contains marking features as a supplement to or in addition to the support structure, the marking features comprising metallic and/or other radiopaque shaped parts within the support structure.

15. The marking device according to claim 1, wherein the wire sections cross repeatedly to form a pattern.

16. The marking device according to claim 1, wherein the at least one elastic metal wire comprises a plurality of wires, each of the plurality of wires having first and second ends, wherein the plurality of wires are secured to one another by a clamp or cap at the first and/or second ends.

17. The marking device according to claim 1, wherein the at least one elastic metal wire comprises a plurality of wires, the plurality of wires comprising a first wire made from a first material and a second wire made from a second material, different from the first material.

18. The marking device according to claim 1, wherein, in the expanded state, the support structure has a hollow, spherical shape.

19. The marking device according to claim 1, wherein, during implantation into the tissue, in the expanded state, the support structure fills a surgical cavity.

20. An implantation system comprising: a marking device according to claim 1; and an implantation device comprising a cannula, the marking device being located within the cannula and configured to move out of the cannula by actuation of the implantation device.

21. The implantation system according to claim 20, wherein the implantation system is configured for use within a vacuum biopsy unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features and details of the invention are revealed by the following description of the preferred embodiments and with reference to the drawing, showing in:

(2) FIG. 1 a first variant of a marking device according to the invention,

(3) FIG. 2A-B a second variant of a marking device according to the invention in a side view and a front view,

(4) FIG. 3A-C an implantation system consisting of implantation device and marking device in total view and detailed view,

(5) FIG. 4A-C an implantation system in three implantation situations following one another in a temporal sequence,

(6) FIG. 5 a third variant of a marking device according to the invention,

(7) FIG. 6 a fourth variant of a marking device according to the invention,

(8) FIG. 7 a fifth variant of a marking device according to the invention,

(9) FIG. 8a-c a sixth variant of the marking device according to the invention, in which the support structure is formed from a slit tube, in the relaxed state and expanded state, and

(10) FIG. 9 the sixth variant of the marking device according to the invention in the laterally compressed state.

DETAILED DESCRIPTION

(11) FIG. 1 shows a first variant of a marking device 100 according to the invention. The depicted marking device 100 is in the expanded state. It has a support structure 102 which has, in the expanded state, a hollow, approximately spherical shape. The result of this is that the marking device in the expanded state encompasses an interior space 104, which can fill with body fluid in particular. In an improved embodiment, the cavity can be filled with an initially dehydrated hydrogel, which swells through water uptake and uniformly fills out the cavity.

(12) The support structure 102 is formed from at least one wire 103. Said wire can be woven, braided, wound or knitted, or be formed by another appropriate production method to form a support structure 102.

(13) For example, the support structure 102 can be formed by the laying, for example winding, of at least one wire 103, consisting of shape-memory alloy for example, around a shape-forming auxiliary body, the memorization of this shape, for example by means of an appropriate temperature treatment, and the subsequent removal of the auxiliary body. In this case, the at least one wire 103 can be laid such that the result is, for example, a cruciform or honeycombed structure in which wire sections cross repeatedly for example. Alternatively, the at least one wire can be laid in an unstructured manner, for example in the manner of a ball of thread, around the shape-forming auxiliary body.

(14) Alternatively or additionally, the contact points of the at least one wire 103 can be welded among one another for the purposes of fixation or connected to one another via an appropriate alternative method.

(15) The support structure 102 encompasses an interior space 104, which can be empty or filled with, for example, hydrogel, polymer foam or suture material, i.e. preferably with a material having a high transparency for ultrasound.

(16) FIG. 2A shows one variant of a marking device 100′ according to the invention. In said marking device, the support structure 102′ is formed from a multiplicity of wires 103′, which are held together at their longitudinal ends by, in each case, a clamp 105′ in a clamping zone 106′. The clamp 105′ has a length LK, which can, for example, assume a value between 0.5 mm and 3 mm, preferably between 0.5 mm and 1.0 mm. The greater the length LK, the more stable in general the fixation of the wires, though at the same time the proportion of the volume not contributing to the visibility of the characteristic shape of the marking device also increases. Therefore, a decrease in market acceptance of the marking device has to be assumed with an increase in length LK.

(17) In the exemplary embodiment in FIG. 2, the clamp 105′ is designed as a sleeve. Alternatively, the clamp can also have other shapes, for example be designed as a cap. The clamps can thus differ from one another in terms of shape and length for example. This makes it possible to use marking devices having different clamps, meaning that individual marking devices can also be individually identified after implantation.

(18) Preferably the clamp, in particular if the clamp is a sleeve, is textured, e.g. engraved, for instance laser engraved, in order to increase ultrasound visibilty.

(19) Further differentiating features of individual marking devices can be clamps composed of differing material, for example clamps which are more or less highly radiopaque or else clamps having different magnetic properties especially for differentiation in images taken by magnetic resonance imaging.

(20) Accordingly, individual wires 103′ of the support structure 102′ can also consist of a different material than the other wires in order to individualize marking devices or else in order to produce certain features in various imaging methods.

(21) Instead of clamps in the narrower sense, which bring about the wire ends being held together by clamping forces, it is also possible to use caps, which are connected to the wire ends by, for example, laser welding or another joining technique.

(22) Especially caps for holding together the wire ends can be shaped differently and thus bring about individualization.

(23) Suitable materials for the clamps, caps or sleeves are, for example, titanium, gold, iron-containing alloys, nitinol, permalloy, mu-metal, neodymium, alnico, or materials having different magnetic properties, i.e. they can be paramagnetic or diamagnetic and thus be detectable by means of a coil for example.

(24) Furthermore, the marking device 100 has a length LM, which specifies the spread of the total marking device in the axial direction. In this development, said length is formed from the length of the support structure 102, and the lengths LK of the two clamps 105. If the support structure of the marking device is fixed by, for example, welding of the at least one wire instead of with clamps, the length LM changes accordingly. The length LM can, for example, assume a value between 3 mm and 9.5 mm, preferably between 3 mm and 6 mm.

(25) The marking device 100 has a diameter DM, which is formed by the radial expansion of the support structure 102 in the expanded state. Said expanded state of the marking device 100 is achieved by its support structure 102 consisting of at least one wire 103 spreading, after deployment from the cannula 242 of the implantation device 200, against a tissue pressure prevailing at the tissue site to be marked, and thus passing from the laterally compressed state into the expanded state.

(26) This independent expansion is achieved by the support structure 102 being formed from a material having a high elasticity, more particularly superelastic behaviour. More particularly, said behaviour can be achieved by the use of a superelastic material, for example nitinol.

(27) In the compressed state of the support structure 102, the diameter DM of the marking device 100 assumes a low value, more particularly a value less than or equal to the inner diameter DKI of the cannula 242 of the implantation device 200.

(28) FIG. 2B depicts the marking device 100 in a front view. In said view, it is possible to see the front view of one of the two clamps 105, in which the wires 103 of the support structure 102 have been fixed together. In this development, the support structure consists of 24 individual wires, which have been fixed in parallel alignment in a clamping zone 106 and the end faces of which can be seen in said front view.

(29) The clamp 105 has a diameter DK, which can, for example, assume a value between 0.6 mm and 2.1 mm, preferably between 0.6 mm and 1.2 mm. The diameter DK influences the smallest possible cannula diameter of the implantation device 200, by means of which the marking device 100 is implanted in tissue. The larger the diameter DK, the larger the diameter of the cannula 242 also needs to be in order to ensure pass-through ability when preloading and deploying the marking device 100.

(30) FIG. 3A depicts an implantation system 300 comprising a marking device 100 and an implantation device 200. Here, the marking device 100 is in the preloaded state, i.e. with compressed support structure 102, within the cannula 242 of the implantation device 200. This state of the implantation system 300 represents a typical shipped state, providing the implantation system ready for use by the user, for example a surgeon.

(31) The implantation part 240 of the implantation device 200 essentially consists of a cannula 242, having at the front end, on the side facing away from the handle 210, a cannula tip 244. In this region within the cannula 242, just before the outlet at the cannula tip 244, the marking device 100 is generally in the preloaded state. The cannula 242 can be formed particularly from a suitable metal.

(32) The cannula 242 has a length LKA, which can, for example, assume a value between 25 mm and 200 mm, preferably between 50 mm and 150 mm. The length LKA of the cannula 242 influences the reach of the implantation device 200 with respect to the accessibility of tissue sites in the body of a patient that are to be marked. When using adjusting aids, for example in stereotaxy, longer cannulas are used.

(33) Furthermore, the implantation device 200 comprises a handle 210 and an implantation part 240. The handle 210 in turn comprises a handle housing 212 and a sliding element 214, which can, for example, be produced from a suitable plastic.

(34) The sliding element 214 is connected to the handle housing 212, but is movable relative to the handle housing 212 in the axial direction of the cannula 242. Therefore, the sliding element 214 can be moved on a straight, guided sliding path between a preload position 218 and a deployment position 220.

(35) This movement is transferred from the sliding element 214, via a deployment element 216 which is connected to the sliding element 214 and which can, for example, be formed via a wire or a sufficiently stable plastics fibre, into the front region facing away from the handle 210. Therefore, upon movement of the sliding element 214 into the deployment position 220, the preloaded marking device 100 can be deployed, by means of a sliding movement of the deployment element 216, from the cannula 242 to the tissue site to be marked at the distal end of the cannula 242.

(36) This is achieved by the deployment element 216 aligned coaxially in relation to the cannula 242 moving in the direction of the cannula tip 244 and hence sliding the preloaded marking device 100 past the cannula tip 244 out of the cannula 242.

(37) FIG. 3B depicts detail B from FIG. 3A, specifically a detailed view of the implantation system 300 in the preloaded state, in the region of the cannula tip 244. In said view, it is possible to see in particular the marking device 100 in the laterally compressed state, which marking device 100 is situated, from the perspective of the handle 210, behind the deployment element 216 and in front of the cannula tip 244 within the cannula 242. Owing to its pretension, the marking device 100 retains its position in the cannula 242 and cannot fall out independently. This property means that it is possible to dispense with additional features or devices for the fixation of the marking device 100 within the cannula 242.

(38) FIG. 3C shows in turn, as detail C from FIG. 3B, a more detailed, schematic view of the cannula 242. In said view, it is possible to see the distal end of the deployment element 216 within the cannula 242. Furthermore, the outer diameter DKA and the inner diameter DKI of the cannula 242 are labelled.

(39) The inner diameter DKI of the cannula 242 describes, together with the cannula length LKA, the size of the inner cavity formed by the cannula 242 and limits at the same time the maximum possible diameter DM of the marking device 100 in the laterally compressed state or possibly the maximum possible diameter DK of the at least one clamp 105 in order to ensure a pass-through ability or mobility of the marking device 100 within the cannula 242 during preloading and deployment. An inner diameter DKI of less than 1.1 mm, particularly preferably of 1.0 mm, has been found to be preferable.

(40) The outer diameter DKA of the cannula 242 describes the diameter of the outer cannula wall. With an increasing outer diameter DKA, the inner diameter DKI of the cannula 242 simultaneously increases, assuming a constant, smallest possible cannula wall thickness, and so does the maximum possible outer diameter of a marking device 100 to be implanted. However, at the same time, an increasing outer diameter DKA leads to a higher degree of invasiveness or injury of skin and tissue when carrying out the implantation.

(41) A sufficiently small outer diameter DKA ensures the possibility of a percutaneous implantation of the marking device 100 without being dependent on a stab incision of the skin at the insertion point of the cannula 242 or on an anaesthetization of the tissue concerned. An outer diameter DKA between 1 mm and 1.5 mm, particularly preferably of 1.2 mm, has been found to be preferable.

(42) FIGS. 4A-C depict schematically an implantation system 300 in three implantation situations following one after another in time, with each situation showing part of the implantation system: in each situation, the distal end of an implantation device 200 in a tissue 260 is depicted.

(43) In FIG. 4A, the implantation system 300 is in the preloaded state, specifically with a cannula 242 containing a compressed marking device 100, said cannula 242 being positioned such that the cannula tip 244 is situated at the site 250 of the tissue 260 that is to be marked. This positioning of the cannula tip 244 is generally effected by the user, for example a surgeon, with the aid of imaging methods, for example ultrasound.

(44) FIG. 4B depicts a subsequent step, in which the marking device 100 is, by forward sliding of the deployment element 216 and withdrawal of the cannula 242, slid past the cannula tip 244 out of the cannula 242 and is thus deployed at the tissue site 250 to be marked. In the course of this, the marking device 100 expands itself so as to pass from a laterally compressed state into an expanded state, through expanding of the support structure 102 even against a tissue pressure acting on the marking device 100 at the site 250 to be marked.

(45) FIG. 4C lastly depicts how the implantation device 200 is, after deployment of the marking device 100, removed from the site 250 in the tissue 260 that is to be marked and finally from the body of the patient by withdrawal of the cannula 242 and of the deployment element 216. In the course of this, the marking device 100 remains in the expanded state at the tissue site 250 to be marked. The channel formed by the cannula 242 from the insertion point at the skin to the tissue site 250 to be marked normally closes again after removal of the implantation device 200 from the body of the patient.

(46) In a further embodiment of the implantation system, the cannula 242 is connected to the sliding element 214 and the deployment element 216 is connected to the handle housing 212. Thus, the relative movement required in order to deploy the marking device 100 is generated by a withdrawal of the sliding element 214. In the course of this, the deployment element 216 remains at its position and likewise holds the marking device 100 at its position during the backward movement of the cannula 242. This has the advantage that the marking device 100, after positioning by means of the implantation device 100, no longer alters its position. The risk of an unfavourable positioning at a position deviating from the tissue site 250 to be marked can thus be reduced. Furthermore, the marking device 100 remains at the end of the pierce channel in this case and is, upon deployment, not pressed against uninjured tissue and/or deformed.

(47) FIG. 5 shows a third variant of an inventive marking device 102′, the support structure 102″ of which is formed by a multiplicity of wires 103′″, which are connected to another at one longitudinal end of the mark using a cap 107″ acting as a clamp. At the other end of the marking device 100″ on the right of the figure, the wires 103″ are connected to one another using a clamp 105″ at a slight distance from their particular longitudinal end, such that longitudinal ends 108″ project beyond the clamp 105″ as free longitudinal ends. Said free longitudinal ends 108″ are bent in a hook-shaped manner and thus support a secure anchoring of the marking device 100″ in tissue. Furthermore, the marking device 100″ displayed in FIG. 5 can easily be palpated in the tissue by a physician after implantation.

(48) FIG. 6 shows a fourth variant of an inventive marking device 100′″, whose interior space 104′″ encompassed by the support structure 102′″ is surrounded by a material layer 109′″ which is in contact with the support structure 102′″ and encompasses a hollow interior space 104′″. The material layer 109′″ can, for example, contain air bubbles, particles of hydrogel or a combination of these constituents in order to thus influence the visibility of the marking device 100′″ under ultrasound or in X-ray. To influence the visibility of the marking device 100′″ in magnetic resonance imaging, the layer can consist of a metamaterial which eliminates or modifies susceptibility artefact in magnetic resonance imaging.

(49) FIG. 7 shows a fifth variant of an inventive marking device 100″″, whose interior space 104″″ is enclosed by a membrane 110″″ which is held in position against the inside of the support structure 102″″. Suitable materials for such a membrane 110″″ are, for example, silicone or polyurethane. The membrane 110″″ can be filled with hydrogel or ICG (indocyanine green), magnetic nanoparticles, a fluorescent medium, medicaments, cells or radioisotopes or a combination of these ingredients. Instead of fitting it on the inside of the support structure 102″″, the membrane can surround the support structure on the outside. Such a membrane entails the advantage that the interior space encompassed thereby alters as little as possible over the course of time.

(50) FIGS. 8a to 8c show various views of a sixth variant of a marking device 100′″″, the support structure 102′″″ of which is formed by a slit tube 111′″″. Since the longitudinal ends 112′″″ of the tube 111′″″ are not slit, the support structure does not require any end-caps or clamps. However, they can nevertheless be provided, for example for marking purposes. Segments 113′″″ separated from one another by slits 112′″″ arch outward in the relaxed, expanded state of the marking device 100′″″ and thus encompass an interior space 103′″″ which is, for example, approximately spherical. As in the other exemplary embodiments, said interior space can be empty or filled with, for example, hydrogel, polymer foam or suture material or enclosed by a membrane or a material layer.

(51) FIG. 8a is a perspective view of the sixth variant of the marking device 100′″″, FIG. 8b is the side view thereof and FIG. 8c is the end-face view thereof.

(52) FIG. 9 shows the sixth variant of the marking device 100′″″ in the compressed state, in which it is easy to identify that the marking device 100′″″ is made from a slit tube. The marking device 100′″″ can be produced such that the tube 111′″″ is first provided with slits 112′″″ and then axially compressed in the longitudinal direction such that the segments 113′″″ bend outward and, in doing so, deform in a plastic manner, meaning that the relaxed state of the marking device 100′″″ is that having outwardly arched segments 113′″″, as displayed in FIGS. 8a to 8c. In its relaxed state, marking device 100′″″ is thus axially compressed and laterally expanded. Preferably, tube 111′″″ is textured so as to increase ultrasound visibility. In particular, the tube can be engraved, for instance laser engraved.

(53) In an unshown modification of the exemplary embodiment displayed in FIGS. 8a to 8c, only one longitudinal end of the tube is unslit, meaning that the segments separated from one another by the slits each have a free longitudinal end. Said free longitudinal ends of the segments can then in turn by held together by a sleeve or a cap. In this way, it is also possible to generate a marking device similar to the one from FIG. 5.

LIST OF REFERENCE SIGNS

(54) 100 Marking device 102 Support structure 103 Wire 104 Interior space 105 Clamp 106 Clamping zone 107 Cap 108 Free longitudinal end 109 Material layer 110 Membrane 111 Tube 112 Slit 113 Segment DK Diameter of clamp LK Length of clamp LM Length of marking device DM Diameter of marking device DKI Inner diameter of cannula DKA Outer diameter of cannula LKA Length of cannula 200 Implantation device 210 Handle 212 Handle housing 214 Sliding element 216 Deployment element 218 Preload position 220 Deployment position 240 Implantation part 242 Cannula 244 Cannula tip 250 Tissue site to be marked 260 Tissue 300 Implantation system