braided tubular implant

For treating disorders of voids in the living Organism tubes hollow bodies, so-called stents, as Stents implanted. They serve the rail-like reinforcement or support of hollow bodies in humans or animals. Typical applications are for example the vascular System, the gastrointestinal system and the urethral system. Typically, stents in compressed form by means of a Catheter through the treated hollow body up and the brought the desired treatment and released there. The Deployment of the compressed stent in the catheter is carried out by own Spring restoring forces due to the stent design principle or by balloon dilation. It is necessary that the stent over long Time can join dynamic and static deformations without To learn appreciable loss of their initial restoring forces. Ideally, it is required that the stent with respect to the lumen and in flexibility adjusts the location and permanently than Implant remains in the body.

Numerous stents have been developed, consisting of metallic Materials, synthetic materials, absorbable in the body or non-absorbable material, and a combination of materials, are prepared, for example in the form of a coating.

U.S. Patent No. 4,655,771.; 4,768,507 and 4,907,336 describe self-expandable, non-resorbable stents. US Pat. No. 4,990, 155 discloses a thermo-reversible, non-resorbable stent. In EP 0335341 and US Pat. No. 4,799,479 are balloon-not resorbable stents described. US Patent Nos. 4,950,258 and 5,670,161 and EP 0809981 relate thermoreversible, resorbable Stents. In U.S. Patent No. 5,980,564.; 5,968,092; 5,500,013; 5,762,625; 6,080,177; 5,306,286; 4,057,537 and the Canadian Pat. No. 2,025,625 and EP 0,797,963 are self-expanding, resorbable stents described.

The stents commercially available at present show in clinical use always unfavorable characteristic profiles and unwanted 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.

It is therefore the object of an improved stent available questions to which the inadequacies of stents from the prior Technique overcomes, is simple and safe to.

This object is achieved by a tubular implant, in particular a stent, in the form of a rounded braiding made in opposed spirals extending intersecting threads of biocompatible material, which is characterized in that the Tube ends are free from thread ends and there existing threads in the Meshwork are returned. In contrast to known Stents, which are cut off from long tubes or hoses and therefore possess interfering thread ends at the tube ends, are those Thread ends not at the tube ends of the stent available. It is therefore not necessary such thread ends cover or incorporate into another material. Under braid preferably diagonal to parent and cruising understand threads.

In this way, the disadvantages are conventionally after a Braiding stents overcome produced which consists of a Variety of monofilament or multifilament threads or wires are formed, in which after the manufacturing process numerous blunt or sharp interfaces and cut edges of the open thread ends occur that, an after-treatment by coating, soldering require welding or laminating to their traumatising preventing effect.

According to the invention, the tubular implant can thereby notable in that it is a tubular, radially compression enabled and having expandable and axially flexible structure. In unloaded State, ie, without the action of external radial forces, the stent a radially uniform tube-like shape. Preferably, the Implant in radial and axial directions to be flexible.

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

In a particular embodiment of the invention the braid is the Implant of a single thread, that is a so-called Continuous filament formed. One of a particular single, Monofilament educated self-expandable stent has a reticular meshwork on.

In a further particular embodiment of the invention, the Braid of the implant of two parallel preferably counter Monofilaments (double strand) to be formed, preferably even when forming the braid of a single continuous thread.

The yarn crossing angle α (see FIG. 1) in the network between them intersecting monofilaments can be greater than 45 °, in particular 70 to 150 °, and preferably from 90 to 120 °. According to the invention bent at the ends of the filaments implant, in particular be formed curved or serpentine. With preference Thread ends, in particular the two ends of the single thread, in the jacket plane or circumferential surface of the circular braid lie. Further can thread ends, in particular all the thread ends, in the each helix are close together and preferably in opposite direction have.

It may be advantageous according to the thread areas at at least one tube end are bent and in the Braid level are returned helically. In a particular Embodiment, thread areas at least on a Pipe end, in particular at one tube end to form a Turnabout bent like a loop and in the same spiral be recycled. In one embodiment, thread areas may at at least one tube end, in particular on a pipe end in an angle of 60 ° to 120 °, particularly by approximately 90 ° and in a be attributed opposing spiral. With preference Thread portions on at least one tube end, in particular at a Tube end forming an intersecting loop around 150 to 300 °, in particular approximately 270 ° bent and counter in a be attributed Wendel.

According to the invention may at least one pipe end, in particular at one tube end alternately thread area around bent 60 ° to 120 ° and one thread area from the same helix be bent by 150 to 300 ° when intersecting loop and the looped thread in the directly subsequent decline Wendel and the only angularly bent filament in the be attributed to the following parallel declining spiral. On Example of such a design is in the accompanying Figure 4 shown.

The inventive tubular implant can continue be characterized in that it is formed like a grid and in relaxed state, has a lattice width of 0.5 to 8 mm, in particular 2 to 5 mm. The yarn crossing angle may be more than 45 °, in particular 70 to 150 °, preferably from 90 to 120 °.

In a preferred embodiment, the braiding of the implant according to the invention each coil of at least two, especially two, formed parallel next to each other lying threads. In particular, at one end of the stent in even-thread count a helix in each case two adjacent threads in opposite direction run. An example of such an embodiment is shown in the accompanying FIG. 5

According to the invention in one embodiment, the Braid structure having a yarn path 1 over 1, 1 under 1. above. In Alternatively, the braided structure a Yarn path 2 over 2, 2 have described in 2. With advantage can in any Spiral direction with respect to the cross section of the stent 4 to 16, in particular 6 to 12 spirals may be provided.

According to the invention, the tubular implant with radially be formed uniform diameter. In a particular Embodiment of the invention, the tubular implant be tapered terminal, that is, at the end of a smaller have diameters. Such rejuvenation of the stent can be used to The purpose of filtering, z. B. in the bloodstream can be expedient. In a another preferred embodiment of the invention, the tubular implant in the relaxed state issued terminally be, that is at least one, preferably two, ends a larger diameter than in the intermediate region. Such radial expansion may be expedient to dislocations after preventing delivery of the stent.

When tubular implant according to the invention may comprise at least one of the implant ends be formed radially divergent. With In other words, in one embodiment of the invention, one end be expanded the tubular implant. In another Embodiment of the invention, both ends of the tubular be widened implant. Advantageously, the transition from the linear be part of the implant to the divergent end continuously. Such Diameter extension can funnel-shaped or tulip-shaped be formed.

When implant according to the invention, the biocompatible material be metallic material. Typical examples are metal filaments made 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® in question.

In another embodiment of the invention, the be biocompatible material synthetic polymer 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 may preferably polymers based of α-polyhydroxycarboxylic acids, β-polyhydroxycarboxylic or Polyanhydrides in the form of homopolymers, copolymers, Terpolymers, block polymers or mixtures thereof will.

In a particular embodiment of the invention, the biocompatible material, a composition of different Materials, in particular, be a composite. Typical examples are Blend polymers, bicomponent monofilaments as monofilaments with core-shell structure, Metal-polymer composites, especially with metal matrix as well as polymer coated metals. The thread material of Stents may have a surface coating of metal, particularly if the thread material is a polymer.

There can numerous modifications of filaments are used, as it is suitable for the desired application. To the For structured monofilament Hohlkapillar monofilaments coated, Monofilament with single or multi-layer coating. Thus, the comprise monofilament wires a structured cross-section, for example a star-shaped cross section or a cross section with a core-sheath structure.

The filament used in the invention may be in a wide range of fiber strengths and fiber thicknesses (Filament diameters) are present. Preferred diameters are from 10 - 800 microns, particularly 30 - 300 microns, with metal wires and Diameter 30-1000 .mu.m, particularly 50-500 microns in Polymer filaments.

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

Advantageously, the monofilaments can contribute to the formation of the Braid structure of the tubular implant a high tensile strength in Range above 100 N / mm² and / or a high modulus of elasticity in Range above 500 N / mm² exhibit.

The tubular implant of the invention can be advantageously notable in that it is elastic and / or plastically. The elastic and / or plastic properties are based on the Inventive combination of monofilament and Meshwork.

In further development, the tubular implant originally pored woven structure at least partially on the inside and / or the outer side be covered by a coating. In a Alternatively, the originally open-pore Braid structure at least partly on the inside and / or the Outside be covered by a coating. As coating can advantageously materials with elastic and / or plastic Properties be used.

A coating can implant the invention fully embed. Alternatively, only certain parts of the implant with be provided a coating, for example, one or both End up. The coating may cover only the thread material, so that the diamond-shaped openings of the braid are uncovered. The Coating can, in particular elastic Coating material close the Implantatwandung. The Coating can be carried out in the form of a so-called Covering be, the tubular implant to an already preformed envelope or a film is wound and thus the inside and / or outside is coated. In another procedure, a Coating are made as so-called coating, wherein Structural elements of the tubular implant with a Coating material an intimate physical and / or chemical Connection received. The coating material may resorbable be.

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

Advantageously, the inventive implant in training can use be provided at least one additive. In particular, the Additive be a pharmacological agent. As examples of such additives are agents for improving the Antitrombogenität as hirudin, prostacyclin, to name heparin. When using the Inventive implant as Drug Delivery Carrier to Release of active ingredient, additives such as anti-cancer agents, For example, Taxol®, Thalodmide® be added. In another Embodiment may be an x-ray marker of additive. For a Drug Delivery In particular, a coating or a coating be formed of the yarn material. In a specific embodiment, the additive living cells be.

Advantageously, additives in the implant of the invention with Using coating technologies are introduced. It is Depending on the choice of the active ingredients and of the coating process possible additives to dope the surface and / or in the store polymer matrix. In this way, a release of the one or more added ingredients on the Degradation and / or resorption of Polymer material used are controlled.

The invention also provides a process for producing a tubular implant made of biocompatible material in Monofilamentform by textile braiding to form a flexible tubular braid with terminal closed Structure. For the formation of the tubular implant according to the Invention, the braiding with advantage over a mandrel made will. In a preferred embodiment, the braiding is machined, especially made automatically. The crude braid can a Postforming, thermal treatment (annealing), coating, Covering, coating or any combination of such Edits are subjected. Preferably, the crude braid be post-treated thermally for the tubular implant.

The 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 unnecessary.

Advantageously, a tubular implant is suitable according to the invention for use in the treatment of pathologically changed Defects in hollow organs in human medicine and Veterinary medicine. Examples are: malignant and benign Obstructions, stenoses, protuberances (aneurysms) and lesions of 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 the urinary tract and ureters. With Particularly advantageously, the tubular implant according to the Invention find use in hollow organs in the vascular, gastrointestinal, tracheobronchial and / or urethral area.

The inventive tubular implant is adapted to receive a human or animal hollow organ via a particular support time interval or duration and / or to keep open. This Time interval depends on the selected material and, depending on medical requirement be adjusted precisely. Also, with the inventive implant mechanical and physiological Requirements, such as diameter, restoring force, compressive force and Flexibility be set very accurately.

For practical use, the tubular implant according to the Invention with commercially available catheters compressed to the brought the treatment with conventional release systems in situ to be placed. The inventive tubular implant self-expanding due to its structure and is a suitably chosen restoring force against the treatable Hollow organ pressed.

Hereinafter, the present invention is carried Description particular embodiments by way of examples and with reference explained to the accompanying drawings. In these Embodiments may individual features of the invention alone or in Combination be realized with other features. A particular embodiment disclosed merely serves to Explanation and better understanding of the invention and is in no way be construed as limiting.

Brief Description of the Figures

Fig. 1 shows an end portion of an uncompressed tubular Stents. The arrows indicate the shift options Monofilaments in the braid structure of the present invention tubular implant to. With α the thread crossing angle is in Braid called. At end of the stent, the monofilaments are bent and in the same helical returned.

Fig. 2 shows the stent of Figure 1 and under radial compression and axial dilation. The arrows indicate the action of the Compression force.

Fig. 3 shows a fully expanded tubular stent with both sides diverging ends, ie with tulip Extensions at the distal and proximal ends. These Embodiment is described in Example 1st The two pipe ends show a different return of the filaments in the outer layer the tubular braid. The braid consists of a single monofilament Thread. The two unseen thread ends together may be joined lie in the outer surface of the braid.

Fig. 4 shows, in an embodiment at the end of the Filamentverlauf Braiding stents, particularly at one (upper) end of the stent by Figure 3. It can be clearly seen, the entanglement, so no free thread ends stick out at the end. On pipe end alternate angled and crosses entangled yarn ranges from.

Fig. 5 shows in another embodiment the at Filamentverlauf End of the braided stent, in particular at a different (lower) 3. end of the stent according to FIG Again looped Thread loops to see, so that no free thread ends at the end protrude.

All figures are per two monofilaments pairs in the spirals out of the braid, which is preferable.

example 1

Stent for the area esophagus / trachea

The thread material used is a polyester monofilament from Polyethylene terephthalate (PET) with a filament diameter of 0.3 mm. The braid was a yarn crossing angle of 110 ° formed over a mandrel of 18 mm diameter. The stent ends are radially divergent on both sides. The diameter of the end of the stent is 24 mm. See FIG. 3.

example 2

Stent for the area bile duct

The thread material used is a Polylactidmonofilament of PL-LA having a filament diameter of 0.3 mm. The braid was with a yarn crossing angle of 100 ° over a mandrel of 8 mm formed diameter. The stent has a uniform lumen on, that is, the stent ends are not designed to diverge, 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 of the type W 1.4310 with a diameter of 0.15 mm. The braid was measured with a thread crossing angle of 90 ° over a mandrel of 22 mm diameter formed. The stent is radially one-sided divergently formed. The diameter is at the end of the stent 28 mm.

The preparation of the implant according to the invention, in particular Stents is possible by machine braiding. In a preferred Embodiment, a single, especially monofilament, thread in parallel longitudinal loops in tubular Arrangement laid. These loops of two parallel juxtaposed threads are simultaneously turns right and left beaten and interrelated nature, resulting in a Hose or tube braid of right- and left-handed helices results which are then fixed, in particular heat-fixed.