braided tubular implant

p0001For treating disorders of voids in the living body are tube-shaped hollow body, so-called stents, implanted as endoprostheses. They serve the rail-like reinforcement or support of hollow bodies in humans or animals. Typical applications include, for example, the vascular system, the gastrointestinal system and the urethral system. Typically, stents are placed in a compressed form via a catheter through the hollow body to be treated and to the desired treatment site and released there. The deployment of the compressed stent in the catheter is carried out by its own spring restoring forces due to the stent design principle or by balloon dilation. It is necessary that the stent can join dynamic and static deformation for a long time to learn without appreciable loss of their initial restoring forces. Ideally, it is required that the stent with respect to the lumen and with respect to the flexibility of adapting the location and remains permanently as an implant in the body.

p0002Numerous stents have been developed which are made of metallic materials, synthetic materials absorbable in the body or non-absorbable material, and a combination of materials, for example in the form of a coating.

p0003The <patcit id="pcit0001" dnum="US4655771A"><text>US Patent Nos. 4,655,771</text></patcit>; <patcit id="pcit0002" dnum="US4768507A"><text>4,768,507</text></patcit> and <patcit id="pcit0003" dnum="US4907336A"><text>4,907,336</text></patcit> describe self-expandable, non-resorbable stents. <patcit id="pcit0004" dnum="US4990A"><text>US Pat. No. 4,990</text></patcit>. <patcit id="pcit0005" dnum="US155A"><text>155</text></patcit> discloses a thermo-reversible, non-resorbable stent. In<patcit id="pcit0006" dnum="EP0335341A"><text>EP 0335341</text></patcit> and <patcit id="pcit0007" dnum="US4799479A"><text>US Pat. No. 4,799,479</text></patcit> balloon-described, non-resorbable stents. <patcit id="pcit0008" dnum="US4950258A"><text>US Patent Nos. 4,950,258</text></patcit> and <patcit id="pcit0009" dnum="US5670161A"><text>5,670,161</text></patcit> as <patcit id="pcit0010" dnum="EP0809981A"><text>EP 0809981</text></patcit> concern thermoreversible, absorbable stents. In the<patcit id="pcit0011" dnum="US5980564A"><text>US Patent Nos. 5,980,564</text></patcit>; <patcit id="pcit0012" dnum="US5968092A"><text>5,968,092</text></patcit>; <patcit id="pcit0013" dnum="US5500013A"><text>5,500,013</text></patcit>; <patcit id="pcit0014" dnum="US5762625A"><text>5,762,625</text></patcit>; <patcit id="pcit0015" dnum="US6080177A"><text>6,080,177</text></patcit>; <patcit id="pcit0016" dnum="US5306286A"><text>5,306,286</text></patcit>; <patcit id="pcit0017" dnum="US4057537A"><text>4,057,537</text></patcit> and the Canadian patent no. <patcit id="pcit0018" dnum="CA2025625"><text>2,025,625</text></patcit> as in <patcit id="pcit0019" dnum="EP0797963A"><text>EP 0,797,963</text></patcit> described self-expandable, resorbable stents.

p0004A tubular implant, in particular stent, in the form of a rounded braiding made in opposed spirals intersecting threads, which lies at the tube ends of the implant thread spaces free of yarn ends and there existing threads are returned to the braid structure is made of <patcit id="pcit0020" dnum="US6632241B1"><text>US 6,632,241 B1</text></patcit> known. Another generic stent is made of<patcit id="pcit0021" dnum="US6007574A"><text>US 6,007,574</text></patcit> known. A stent for expanding a body lumen is in the<patcit id="pcit0022" dnum="EP0857471A2"><text>EP 0857471 A2</text></patcit> described. In the<patcit id="pcit0023" dnum="US5540713A"><text>US 5,540,713</text></patcit> a device for widening a stenosis in a body tube is described. The device is based on an alloy with shape memory and a substantially cylindrical circumferential outer contour. The<patcit id="pcit0024" dnum="US5968088A"><text>US 5,968,088</text></patcit> relates to an expandable stent with a flexible tubular body.

p0005The stents commercially available at present show in clinical use again unfavorable characteristic profiles and adverse clinical outcomes such as fatigue, Stentdislokation, inflammation, thrombosis or restenosis. These disadvantages affect the success of treatment and the sustainability of treatment to the detriment of the patient.

p0006It is therefore the object to provide an improved stent available that overcomes the inadequacies of stents from the prior art, is simple and safe to.

p0007This object is achieved by a tubular implant, particularly a stent, according to Claim first

p0008In contrast to known stents which are cut from long tubes or hoses and therefore have troublesome thread ends at the tube ends, such thread ends at the tube ends of the stent are not present. It is therefore not necessary to cover such thread ends or incorporate into another material. Under braid are preferably diagonal to parent and to be understood by intersecting threads.

p0009In this way, the disadvantages of conventional produced by a braiding stents are overcome, which are formed from a plurality of monofilament or multifilament threads or wires in which, after the manufacturing process a number of blunt or sharp interfaces and cut edges of the open yarn ends occur, the post-treatment by coating , soldering, welding or laminating require, in order to prevent their traumatizing effect.

p0010According to the invention, the tubular implant can be characterized in that it comprises a tubular, radially expandable and capable compression and axially flexible structure. In the unloaded state, ie, without the action of external radial forces, the stent has a radially uniform tube-like shape. The implant is preferably in radial and axial directions can be flexible.

p0011Advantageously, the inventive implant may be formed of threads which are monofilament wires. The monofilament wires (monofilaments) can have up to 500 microns in diameter of 30 microns to 2 mm, in particular 70 microns. In a further parallel wires can be twisted slightly together.

p0012In a particular embodiment of the invention, the braiding of the implant from a single thread, that is a so-called continuous filament formed. One of a particular single monofilament educated self-expandable stent has a net-like mesh structure.

p0013In another particular embodiment of the invention, the braid of the implant of two parallel preferably opposite monofilaments (double strand) to be formed, and preferably also in forming the braid of a single continuous thread.

p0014The yarn crossing angle α (see FIG. <figref idrefs="f0001">figure 1</figref>) In braid intersecting therebetween monofilaments can be greater than 45 °, in particular 70 to 150 °, and preferably be from 90 to 120 °. According to the invention, the filaments may be bent, formed in particular curved or serpentine manner to the implant ends. Preference can thread ends, in particular the two ends of the single thread, are in the shell plane or circumferential surface of the circular braid. Furthermore, thread ends, in particular all the thread ends, lie close to one another in the respective helix and preferably point in opposite direction.

p0015It may be advantageous that the thread portions are bent at at least one end of the tube and are returned helically in the mesh plane. The thread portions may be bent like a loop at least at one tube end, in particular at one tube end to form a U-turn and returned to the same spiral. The thread portions are returned to at least one tube end, in particular on a pipe end at an angle of 60 to 120 °, particularly by approximately 90 ° and in a reverse helix. The thread portions are bent at least at one tube end, in particular on a pipe end to form an intersecting loop around 150 to 300 °, in particular approximately 270 °, and returned in a reverse helix.

p0016According to the invention at least one tube end, in particular at one tube end alternately bent a thread portion to 60 to 120 ° and one thread area from the same helix at 150 to 300 ° bent when intersecting loop and the looped thread in the directly subsequent declining spiral and the only angularly bent yarn in the subsequent parallel decline Wendel returned. An example of such embodiment is shown in the accompanying<figref idrefs="f0003">figure 4</figref> shown.

p0017The inventive tubular implant can further be characterized in that it is formed like a grid and in the relaxed state has a mesh size of 0.5 to 8 mm, in particular 2 to 5 mm. Thereby, the thread crossing angle of more than 45 °, in particular 70 to 150 °, preferably from 90 to 120 °.

p0018In a preferred embodiment, the braiding of the inventive implant each filament of at least two, especially two, formed parallel next to each other lying threads. In particular, may run in the opposite direction at a stent end at even-thread count a spiral each two adjacent threads. An example of such embodiment is shown in the accompanying<figref idrefs="f0004">figure 5</figref> shown.

p0019According to the invention may include a yarn path 1 over 1, 1 under 1 in one embodiment, the braided structure. In another embodiment, the braid structure having a yarn path 2 over 2, 2 described in 2. Advantageously can in each helix direction relative to the cross section of the stent 4 to 16, can be provided in particular 6 to 12 filaments.

p0020According to the invention may be formed with radially uniform diameter, the tubular implant. In a particular embodiment of the invention, the tubular implant may be tapered terminal, that is, at the end having a smaller diameter. Such rejuvenation of the stent may be expedient for the purpose of filtering, z. B. in the bloodstream. In another preferred embodiment of the invention, the tubular implant to be issued at the end in the relaxed state, that is, at least one, preferably both, ends have a larger diameter than in the intermediate region. Such radial expansion may be advisable to avoid dislocations after introduction of the stent.

p0021When tubular implant according to the invention may be formed radially diverging at least one of the implant ends. In other words, it can be flared in an embodiment of the invention, one end of the tubular implant. In another embodiment of the invention, both ends of the tubular implant can be widened. Advantageously, the transition from the linear portion of the implant to the divergent end can be infinitely. Such expanded diameter can be funnel-shaped or tulip-shaped.

p0022When the implant according to the invention, the biocompatible material may be metallic material. Typical examples are metal filaments made of titanium, titanium alloys, stainless surgical steel such as Cr-Ni-steels, W1.4310, Elgiloy®, Phynox®, iridium or Metalloxidlegierungen. Furthermore, so-called shape memory metals such as Nitinol® eligible.

p0023In another embodiment of the invention can be synthetic polymer material, the biocompatible material. Typical examples are filaments made of synthetic polymers such as polyethylene terephthalate (PET), polyurethane (PUR), polypropylene (PP), high density polyethylene (HDPE), polyamide, copolymers, blends or mixtures of such polymers. For absorbable implants or absorbable parts of implants polymers based on α-polyhydroxycarboxylic acids, β-polyhydroxycarboxylic or polyanhydrides can be used in the form of homopolymers, copolymers, terpolymers, block polymers or mixtures thereof are preferred.

p0024In a particular embodiment of the invention, the biocompatible material is a composition of different materials, in particular, be a composite. Typical examples are blend polymers, bicomponent monofilaments such as monofilaments having a core-sheath structure, metal-polymer composites, in particular with metal matrix as well as polymer coated metals. The thread material of the stents may have a surface coating of metal, particularly if the thread material is a polymer.

p0025There can be used various modifications of filaments, as is appropriate for the desired application. For example, structured monofilament Hohlkapillar monofilaments, coated monofilaments with single or multi-layer coating. So may have a structured cross-section of the monofilament wires, for example, a star-shaped cross-section or a cross section with a core-sheath structure.

p0026The filament used in the invention may be in a wide range of fiber thickness and fiber thicknesses (filament diameters). Preferred diameters are 10-800 microns, particularly 30-300 microns in diameter metal wires and 30-1000 .mu.m, particularly 50-500 microns, in polymer filaments.

p0027In one embodiment of the invention, the biocompatible material is not bioresorbable. In another embodiment of the invention may be at least partially bioresorbable biocompatible material. In yet another embodiment of the invention may be fully bioresorbable the biocompatible material.

p0028Advantageously, the monofilaments a high tensile strength in the range can contribute to the formation of braided structure of the tubular implant about 100 N / mm² and / or a high modulus of elasticity in the range of about 500 N / mm² exhibit.

p0029The tubular implant of the invention can advantageously be characterized in that it is elastic and / or plastically. The elastic and / or plastic properties are based on the inventive combination of monofilament and braid structure.

p0030In a further development may be at least partially on the inside and / or outside covered by a coating in tubular implant originally open-pore braid structure. In another embodiment, at least partially on the inside and / or outside be covered by a coating, the originally open-pore braid structure. The coating may be used with elastic and / or plastic properties advantageously materials.

p0031A coating can completely embed the inventive implant. Alternatively, only certain parts of the implant may be provided with a coating, for example, one or both ends. The coating may cover only the thread material, so that the diamond-shaped openings of the braid are uncovered. The coating may be particularly close in the Implantatwandung elastic coating material. The coating may be in the form of a so-called Covering, wherein the tubular implant is already mounted on a preformed shell or a film and thus coated inside and / or outside. In another method, a coating to be made as a so-called coating, wherein structural elements of the tubular implant form an intimate physical and / or chemical compound with a coating material. The coating material can be absorbable.

p0032According to one embodiment of the invention, the coating and / or the coating may be adhesively bonded. According to another embodiment of the invention, the coating and / or the coating may be covalently bound.

p0033Advantageously, the inventive implant may be provided in at least one further additive. In particular, the additive may be a pharmacological agent. As examples of such additives agent for improving the Antitrombogenität such as hirudin, prostacyclin, heparin are mentioned. When using the inventive implant as Drug Delivery Carrier to release additives may be added as anti-cancer agents such as Taxol®, Thalodmide®. In another embodiment, may be an x-ray marker of additive. For a drug delivery in particular can be formed a coating or a coating of the thread material.

p0034In a specific embodiment may be living cells of the additive.

p0035Advantageously additives using coating technologies can be incorporated in the implant according to the invention. It is possible according to the choice of ingredients and the coating process, additives to dope superficial and / or store them in the polymer matrix. In this way a release of one or more of added agents on the degradation and / or resorption of the polymer material used can be controlled.

p0036Subject of description is also a method for producing a tubular implant made of biocompatible material in Monofilamentform. By textile braiding to form a flexible tubular braid with terminally closed structure For the formation of the tubular implant according to the invention, the lichen can be advantageously carried out over a mandrel. In a preferred embodiment, the braiding is machined, made in particular automatically. The crude braid can a post-forming, thermal treatment (annealing), Coating, Covering, coating or any combination of such operations are subjected. Preferably, the crude braid for the tubular implant can be thermally post-treated.

p0037The advantage of the inventive production process is that a distal and proximal closed, atraumatic braid construction is formed. In this way, a lamination of the stent ends and similar post-processing steps is unnecessary.

p0038Advantageously, a tubular implant is suitable according to the invention for use in the treatment of pathologically changed defect sites on hollow organs in human medicine and veterinary medicine. Examples are: malignant and benign obstructions, stenoses, protuberances (aneurysms) and lesions in hollow organs. Typical areas of application for the invention stents are blood vessels, esophagus, trachea, duodenum, colon and other parts of the digestive system and urinary tract and ureters. Particularly advantageously, the tubular implant according to the invention find use in hollow organs in the vascular, gastrointestinal, tracheobronchial and / or urethral area.

p0039The inventive tubular implant is capable of supporting a human or animal hollow organ over a specified time interval or duration and / or to keep open. This time interval depends on the selected material and can be tailored depending on the medical requirements. Also can be adjusted very precisely with the inventive implant mechanical and physiological requirements, such as diameter, restoring force, compressive force and flexibility.

p0040For practical use, the tubular implant can be compressed according to the invention with commercially available catheters, brought to the treatment site and be placed with conventional release systems in situ. The inventive tubular implant is self-expanding due to its structure and is pressed by a restoring force against the correspondingly selected to be treated hollow organ.

p0041Hereinafter, the present invention is illustrated by describing particular embodiments by way of 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. A particular embodiment disclosed is only used for illustration and for better understanding of the invention and is in no way intended to be limiting.

Brief Description of the Figures

p0042<figref idrefs="f0001">Fig. 1</figref> showing an end portion of an uncompressed tubular stents. The arrows indicate displacement possibilities of the monofilaments in the braid structure of the tubular implant according to the invention. With α the thread crossing angle is referred to in the braid. At the end of the stent, the monofilaments are bent and returned to the same coil.

p0043<figref idrefs="f0001">FIG. 2</figref> shows the stent and by <figref idrefs="f0001">figure 1</figref> under radial compression and axial dilation. The arrows indicate the action of the compressive force.

p0044<figref idrefs="f0002">Fig. 3</figref> shows a fully formed tubular stent with both sides diverging ends, that is, with tulip-shaped extensions on distal and proximal ends. This embodiment is described in Example 1st The two pipe ends show a different return of the filaments in the outer layer of the tubular braid. The braid consists of a single monofilament thread. The two thread ends can not be seen, which can be connected to each other, lie in the outer surface of the braid.

p0045<figref idrefs="f0003">Fig. 4</figref> in one embodiment the end of the braided stent Filamentverlauf on, particularly on a (upper) end of the stent by <figref idrefs="f0002">figure 3</figref>, It can be clearly seen the entanglements so that no free thread ends stick out at the end. On pipe end angled and crosses entangled yarn regions alternate.

p0046<figref idrefs="f0004">Fig. 5</figref> shows, in another embodiment the end of the braided stent Filamentverlauf on, in particular at a different (lower) end of the stent by <figref idrefs="f0002">figure 3</figref>, Here are looped thread loops to see, so that no free thread ends stick out at the end.

p0047In all the figures, two monofilaments are pairwise guided in the spirals of the mesh, which is preferable.

example 1

Stent for the area esophagus / trachea

p0048The thread material used is a polyester monofilament of polyethylene terephthalate (PET) with a filament diameter of 0.3 mm. The braid was formed with a thread crossing angle of 110 ° over a mandrel of 18 mm diameter. The stent ends are radially divergent on both sides. The diameter of the stent end is 24 mm. See also<figref idrefs="f0002">Fig. 3</figref>,

example 2

Stent for the area bile duct

p0049The thread material used is a Polylactidmonofilament from PL-LA having a filament diameter of 0.3 mm. The braid was formed with a thread crossing angle of 100 ° over a mandrel of diameter 8 mm. The stent has a uniform lumen on, that is, the stent ends are not formed divergently, and have a diameter of 8 mm.

example 3

Stent for the Colon area

p0050The thread material used is a wire made of stainless steel of the type 1.4310 W with a diameter of 0.15 mm. The braid was formed with a thread crossing angle of 90 ° over a mandrel of 22 mm diameter. The stent is formed on one side radially divergent. The diameter is on the stent end 28 mm.

p0051The preparation of the inventive implant, in particular stent, is possible by machine braiding. In a preferred embodiment, a single, in particular monofilament, yarn is laid in parallel to each other in longitudinal loops tubular assembly. These loops of two parallel juxtaposed threads are simultaneously alternately struck right and left and interrelated nature, wherein a tube or cane yields from right- and left-handed helices, which are then fixed, in particular heat-fixed.