braided tubular implant

European).

OK II-12 / P28897PL00

EP 1 527 751 B1

Woven tubular implant

In order to treat disorders in empty spaces in the living organ, tubular cavernous bodies are implanted, so-called stents, as endoprosthesis. They serve as reinforcement or support, such as splints, cavernous bodies in humans or animals. Typical areas of application are e.g. the vasculature, the gastrointestinal tract and the urinary tract. Typically, the stents are compressed by means of a catheter through the cavities being considered until the desired treatment site and released there. The dilatation of the stent compressed in the catheter occurs through its own spring restoring forces based on the principle of stent construction or dilatation of the balloon. It is required that stents can participate for a long time in dynamic and static deformations, without experiencing a significant loss of their original restoring forces.

Numerous stents have been developed that are manufactured from metal materials, synthetic materials, resorbable or non-resorbable material in the body, and from a combination of materials, e.g. in the form of a coating.

^Opis^s US patents ⁴ 6^55.771; ^{4,768,507 and 4,} 9^07,336 describe self-expanding, non-resorbable stents. U.S. Patent No. 4,990, 155 discloses a thermoreversible, non-resorbable stent. In EP 0335341 and US Pat. 4,799,479 describes balloon-expandable stents, no

- 2 resorbable. U.S. Patent Nos. 4,950,258 and 5,670,161 as well as EP 0809981 refer to thermo-reversible resorbable stents. U.S. Patent Nos. 5,980,564; 5, 968, 092; 5,500,013; 5,762,625; 6,080,177; 5,306,286; 4,057,537 and Canadian Patent No. 2,025,625 and in EP 0,797,963 describe self-expanding, resorbable stents.

A tubular implant, in particular a stent, in the form of a circular mesh of threads crossed in counter-rotating strands, is known from US 6,632,241 B1, wherein the thread areas lying at the ends of the implant tube are devoid of the ends of the thread and the threads present therein are routed back to the mesh structure, . A further, typical stent is known from US 6,007,574. A stent for expanding the light in the body is described in^{EP 0857471} AND². ^{In US 5,540,713} a device for ^paboutspreading the stenosis in the "conduit" in the body. The device relies on a foot with shape memory capacity and an essentially heated shaped outer contour. US 5,968,088 relates to an expandable stent with a flexible tubular body.

In the clinical use, stents presently commercially exhibit still unfavorable profiles of properties and undesirable clinical results, such as material fatigue, stent dislocation, inflammation, thrombosis or restenosis. These deficiencies adversely affect the success of treatment as well as the length of treatment to the disadvantage of the patient.

There is therefore the task of providing an improved stent that overcomes the shortcomings of prior art stents and that can be easily and reliably used.

This task is solved by a tubular implant, in particular a stent, according to claim 1.

In contrast to known stents, which are cut off from long tubes or hoses and therefore on the ends of the tubes have a distortion of the ends of the thread, such ends of the thread are not on

- 3 ends of a tube of the stent according to the invention. Therefore, it is not required that such thread ends be covered or bonded to other material. The net is preferably understood as diagonally running threads crossing above and below.

In this way, the shortcomings of the existing stents made according to weave technology are overcome, which are formed of a plurality of single-stranded or multi-stranded threads or wires in which a number of blunt or sharp cutting positions and cutting edges of the open ends of the thread are required according to the manufacturing process that require post-treatment by coating , soldering, welding or laminating to prevent their action causing injury.

According to the invention, the tubular implant can thereby be distinguished by having a tubular structure, radially squeezable and expandable as well as axially elastic. In the unloaded state, i.e. without the action of external radial forces, the stent exhibits a uniformly radial, tubular form. Preferably, the implant may be flexible in the radial and axial direction.

Advantageously, the implant according to the invention can be formed of threads that are single-stranded wires. The single-stranded wires (monofilaments) may have a diameter of 30 pm-2 mm, in particular 70 pm-500 pm. In a further embodiment, the parallel wires may be slightly recycled.

In a particular embodiment of the invention the mesh of the implant is formed of a single thread, i.e. endless threads. The self-expanding stent formed from, in particular of a single, monofilament has a network-like net structure.

In a further particular embodiment of the invention the mesh of the implant can be formed of two parallel, preferably counter-rotating monofilaments (double band) and preferably also when forming a single-threaded net of endlessly.

The angle of intersection of the thread α (see Figure 1) in the net between intersecting monofilaments may be greater than 45 °, in particular 70^-150 ° ^and leorzptaie in^snose^{ll of} 90^-120 . According to the invention, the filaments may be bent at the ends of the implant, especially shaped in the shape of a curve or type of serpentine. Preferably the ends of the thread, in particular both ends of a single thread, lie in the plane of the shell or the surface of the shell of the circular net. In addition, the ends of the thread, especially all thread ends, may lie in close proximity to each other and preferably indicate the opposite direction.

It may be advantageous that the thread regions at at least one end of the tube are recycled and back in the plane of the weave-shaped mesh plane. The thread regions may at one end of the tube, especially at the end of the tube, be loosened back when the twist is formed and be routed back in the same weave. The thread regions are at least at one end of the tube, especially at the end of the tube at an angle of 60-120 °, in particular around 90 °, and routed back in the counter-current weave. The thread regions are at at least one end of the tube, especially at the end of the tube at the formation of a crossing loop recycled by 150-300 °, especially about 270 °, and routed back in the counter-rotating weave.

According to the invention, at least one end of the tube, especially at the end of the tube, alternately the thread area is turned back by 60-120 ° and the thread area from the same weave is turned back by 150-300 ° as the intersecting loop and the looped thread is guided back directly with the return strand attached and the only angle-reversed thread is guided in the subsequent return weave. An example of such an embodiment is shown in the accompanying figure 4.

The tubular implant according to the invention can furthermore be characterized in that it is formed in the grid type and in the expanded state has a mesh width of 0.5-8 mm, in particular 2-5 mm. In this case, the thread crossing angles can be varied^pthence. ⁴⁵% especially 7^0-150% 9^0-l²⁰°.

In a preferred embodiment, in the mesh of the implant according to the invention, each weave is formed of at least two, in particular two, parallel-lying threads. Especially at the end of the stent, with even number of weave threads, the two adjacent threads can be run in opposite directions. An example of such an embodiment is shown in the accompanying figure 5.

According to the invention, in an embodiment, the mesh structure may exhibit a thread course 1 over 1, 1 under 1. In another embodiment, the mesh structure may exhibit a thread course 2 over 2, 2 under 2. With advantage in each weave direction, it may be provided with respect to the stent section , 4-16, especially 6-12 weaves.

According to the invention, a tubular implant with a radially uniform diameter can be formed. In a particular embodiment of the invention, the tubular implant may be terminally narrowed, i.e. at the end have a smaller diameter. Such stent stenosis may be suitable for filtering, e.g. in the blood stream. In another preferred embodiment of the invention, the tubular implant may be terminally spaced in an expanded state, i.e. on at least one, preferably both end, to have a larger diameter than in the region between them. Such radial dilatation may be appropriate to prevent dislocations after insertion of the stent.

In the case of a tubular implant according to the invention, at least one of the ends of the implant may be present

- 6 radially shaped divergent. In other words, in the embodiment of the invention, the end of the tubular implant can be expanded. In another embodiment of the invention, both ends of the tubular implant can be expanded. Advantageously, the transition from the linear part of the implant to the divergent end can be infinitely variable. This diameter extension can be cone shaped or tulip shaped.

In the case of an implant according to the invention, the biocompatible material may be a metallic material. Typical examples are metal filaments of titanium, titanium alloys, stainless steel for medical purposes such as Cr-Ni steels, W 1.4310, Elgiloy®, Phynox®, iridium alloys or metal oxides. In addition, the so-called shape memory metals such as Nitinol®.

In another embodiment of the invention, the biocompatible material may be a synthetic polymeric material. Typical examples are filaments from synthesized polymers such as polyethylene terephthalate (PET), polyurethane (PUR), polypropylene (PP), high density polyethylene (HDPE), polyamide, copolymers, blends or mixtures of such polymers. The resorbable implants or resorbable parts of the implants may advantageously be applied to polymers based on α-poly-hydroxycarboxylic acids, β-polyhydroxycarboxylic acid or poly-adjuvants in the form of their homopolymers, copolymers, terpolymers, block polymers or mixtures thereof.

In a particular embodiment of the invention, the biocompatible material may be a composition of various materials, in particular a composite material. Typical examples are polymers in the form of a blend, bi-component monofilaments such as core-sheath monofilaments, metal-polymer composite materials, in particular with a metallic matrix, as well as polymer coated metals. The stent thread material may have a surface coating of metal, especially when the thread material is a polymer.

Numerous modifications to the filaments may be used as appropriate for the desired purpose of use. For example, structured monofilaments, monofilaments with an internal capillary, coated monofilaments with a single-layer or multi-layer coating. Thus, single-stranded wires may have a structured cross-section, e.g. a star-shaped cross-section or a cross-section with a core-sheath structure.

According to the invention, the filament material used can be present in a wide range of fiber strength and fiber thickness (filament diameters). Diameters 10-800 μm are preferred, especially 30-300 μm, for metal wires diameters 30-1000 μm, especially 50-500 μm in the case of polymeric filaments.

In one embodiment of the invention, the biocompatible material may not be bioresorbable. In another embodiment of the invention, the biocompatible material may be at least partially bioresorbable. In yet another embodiment of the invention, the biocompatible material can be completely bioresorbable.

Advantageously, monofilaments for shaping the reticular structure of a tubular implant can have a high tensile strength in the range of over 100 N / mm² and / or a high modulus of elasticity in the range of over 500 N / mmi.

The tubular implant of the invention may advantageously be characterized in that it is flexible and / or plastic. The elastic and / or plastic properties are based on the combination of the monofilament and the lattice structure according to the invention.

In a further embodiment, in the case of a tubular implant, the mesh structure may be initially covered with open pores at least partially on the inner side and / or on the outer side covered with a covering. In another embodiment, it is possible to have a reticulated structure initially with open pores at least partially on the inner side and / or on the side

- the outside is covered by the coating. As a coating, materials with elastic and / or plastic properties can be advantageously used.

The coating can completely embed the implant according to the invention. Alternatively, only certain parts of the implant may be provided with a coating, e.g. one or both ends. The coating may cover only the thread material so that the diamond mesh openings are not covered. In particular, in the case of a flexible coating material, the coating can also close the inner walls of the implant. The coating can be made in the form of so-called Covering, wherein the tubular implant is stretched over a previously formed coating or film and that is inside and / or outside covered. In another procedure, the coating may be made as a so-called coating, wherein the structural elements of the tubular implant enter into a physical and / or chemical relationship with the coating material. The coating material may be resorbable.

According to one embodiment of the invention, the coating and / or the coating can be adhesively bonded. According to another embodiment of the invention, the coating and / or coating may be covalently bound.

Advantageously, the implant according to the invention may be provided with at least one additional substance in a further embodiment. In particular, the additive may be a pharmacological active ingredient. Examples of such additive substances include those for improving anticoagulant effects such as hirudin, prostacyclin, and heparin. When using the implant according to the invention as the Drug Delivery Carrier, additional substances such as anti-cancer agents, for example Taxol®, Thalodmide®, may be added to release the active substance. In another embodiment, the additive may be an x-ray marker. For

In particular, the coating or covering of the thread material may be shaped as a drug delivery.

In a particular embodiment, the additive may be living cells.

Advantageously, additional substances may be introduced in the implant according to the invention by means of coating technology. According to the choice of active ingredients and the coating method, it is possible to admix the surface additives and / or to add them to the polymer matrix. In this way, the release of one or more added active ingredients can be controlled by the degradation characteristics and / or the resorption characteristics of the polymeric material used.

The subject of the description is also a method for producing a tube-shaped implant from a biocompatible material in the form of a monofilament by a textile braiding method to form a flexible, tubular mesh with a terminally closed structure. In order to shape the tubular implant according to the invention, the braiding may advantageously be taken by the plunger. In a preferred further embodiment, the braiding is made by machine, especially automatically. The raw net can be subjected to post-forming, thermal post-treatment (warm-up), coating, coating, or any combination of such treatments. post-treatment.

An advantage of the manufacturing method according to the invention is that a distally closed and proximal closed, atraumatic mesh construction is formed. In this way, lamination of the ends of stents as well as similar post-treatment steps are unnecessary.

Advantageously, the tubular implant according to the invention is suitable for the treatment of pathologically changed damage sites in the cavernous organs of human and veterinary medicine. Examples include: malignant and benign occlusions, stenoses, displacement (aneurysms) and damage to the cavernous organs. Typical areas of use of stents according to the invention are blood vessels, esophagus, trachea, duodenum, colon and other parts of the digestive system as well as urinary tract and urinary tracts. The tubular implant according to the invention can be used with particular advantage in cavernous organs in the vascular, gastrointestinal, tracheal-bronchial and / or urinary regions.

The tubular implant according to the invention is suitable for a human or animal cavernous organ for a specific time area or for permanent support and / or maintenance in the open state. This time interval is dependent on the material chosen and can be accurately tailored according to medical demand. The mechanical and physiological requirements, such as diameter, restoring force, compressive strength and flexibility, can also be set very precisely with the implant according to the invention.

For practical use, the tubular implant according to the invention can be compressed with commercially available catheters, brought to the treatment site and placed in situ in conventional release systems. The tubular implant according to the invention is self-expanding due to its structure and is pressed by a suitably selected restoring force to the treated cavernous organ.

The present invention is explained below by describing specific embodiments based on examples and with reference to the accompanying drawings. In these embodiments, individual features of the invention may be implemented alone or in combination with other features. The particular embodiment described is only intended to explain and better understand the invention and should not be construed as a restriction.

- 11 Brief description of the figures

Fig. 1 shows the end section of an unfinished tubular stent. The arrows indicate the possibility of shifting monofilaments in the reticular structure of the tubular implant according to the invention. α is the thread intersection angle in the mesh. At the end of the stent, the monofilaments are turned back and in the same weave are guided back.

Fig. 2 shows the stent according to figure 1 after radial compression and axial expansion. The arrows give the squeeze force.

Fig. 3 shows a completely shaped tubular stent with bilateral ends, i.e. with tulip extensions at the distal and proximal end. This embodiment is described in Example 1. Both ends of the tube show different lead backs in the plane of the tube mesh sheath. The net consists of a single single strand. Both invisible ends of the thread that can be connected to each other lie on the surface of the mesh cover.

Fig. 4 shows in one embodiment the filament waveform at the end of the mesh stent, in particular at one (upper) end of the stent according to figure 3. One can clearly see the loops, so that no free ends of the threads extend at the end. At the end of the tube the bent and loosened areas of the thread change.

Fig. 5 shows in another embodiment the filament waveform at the end of the mesh stent, in particular at the other (bottom) end of the stent according to Figure 3. Also here are loop-like thread loops, so that no free ends of the threads extend at the end.

In the case of all figures, two monofilaments are run in pairs in the mesh strands, which is advantageous.

Example 1

Stent for the area of ​​the esophagus / trachea

- 12 The used thread material is a polyester monofilament made of polyethylene terephthalate (PET) with a filament diameter of 0.3 mm. The mesh was formed at the angle of intersection of the thread 110 ° by a mandrel with a diameter of 18 mm. The ends of the stent are radially diverging on both sides. The diameter of the end of the stent is 24 mm. Regarding this - see Fig. 3.

Example 2

Stent for the bile duct area

The thread material used is a polylactide monofilament from PL-LA with a filament diameter of 0.3 mm. The mesh was formed at an angle of intersection of the 100 ° thread by a spindle with a diameter of 8 mm. The stent exhibits uniformly sustained light, i.e. the ends of the stent are not shaped divergently, and have a diameter of 8 mm.

Example 3

Stent for the colon area

The thread material used is a wire made of stainless steel, type W 1.4310, with a diameter of 0.15 mm. The net is shaped with an angle of intersection of the 90 ° thread by a mandrel with a diameter of 22 mm. The center is shaped on one side radially diverging. The diameter is 28 mm at the end of the stent.

The manufacture of the implant, in particular a stent, according to the invention is possible by machine braiding. In a preferred embodiment, a single, in particular single-strand, thread is arranged in parallel-longitudinally directed loops in a tubular system. The loops of two parallel strands next to each other are alternately driven into the right and left and interlaced one under the other, with the right and left-handed strands resulting in a hose or tubular netting, which then stabilizes, in particular thermally stabilizing.

Deutsche Institut für Textil- und Faserforschung Denkendorf Stiftung des offentlichen Rechts Substitute: