Braided tubular implant

DESCRIPTION

Plaited TUBULAR IMPLANT

For the treatment of disturbances in hollow spaces in the living organism tubular hollow bodies, the so-called stents, are implanted as endoprostheses. These serve for the splint reinforcement or support of hollow bodies in humans or animals. Typical areas of application are for example the vascular system, the gastrointestinal system and the urethral system. Usually, stents are conducted in a compressed form with the aid of a catheter through the hollow body to be treated to the desired treatment site and are released there. The unfolding of the compressed stent in the catheter is effected by elastic return forces based on the principle of stent construction or by balloon dilation. Stents must be able to keep up with dynamic and static deformations over an extended period of time without suffering a significant loss of their original return forces. Ideally, the stent is required to adapt to the site of application with regard to lumen and flexibility and to remain permanently in the body while implanting.

Numerous stents have been developed which are made from metallic materials, synthetic materials, resorbable or non-resorbable material in the body, as well as a combination of materials, for example in the form of a coating.

US patents No. 4,655,771; 4768507 and 4907336 describe non-resorbable and self-expanding stents. US Patent No. 4,990,155 discloses a non-resorbable and thermoreversible stent. EP 0335341 and US Patent No. 4799479 disclose non-resorbable and balloon dilatable stents. US Patent Nos. 4,950,258 and 5,670,161, as well as EP 0809981 refer to resorbable and thermoreversible stents. In US Pat. Nos. 5980564; 5968092; 5500013; 5,726,625; 6080177; 5306286; No. 4057537 and Canadian Patent No. 2025625, as well as EP 0797963 are described as resorbable and self-expanding stents.

From US 6632241 BI, a tubular implant, in particular stent, in the form of a tubular braid from opposite intersecting spiral wires is known, with the wire zones at the ends of the tube of the implant are free of wire ends and the wires therein are routed back to the braid structure. Another stent according to the class is known from US 6007574. A stent for expanding a body lumen is described in EP 0857471 A2. US 5540713 discloses a device for dilating a stenosis in a tubular body structure. The device is based on an alloy with shape memory capability and an essentially cylindrically shaped outer contour. US 5968088 relates to an expandable stent with a flexible tubular body.

In clinical use, currently marketed stents again always show unfavorable property profiles and unwanted clinical results, such as material fatigue, stent dislocation, inflammation, thrombosis or restenosis. These disadvantages influence the success of treatment as well as the sustainability of treatment to the disadvantage of the patient.

For this reason, the goal is to provide an improved stent that overcomes prior art stent deficiencies and can be deployed easily and safely.

This object is solved by a tubular implant, in particular a stent according to claim

1.

Unlike known stents that are cut from long tubes or hoses and therefore have disturbing wire ends at the tube ends, such wire ends do not exist at the ends of the stent tube according to the invention. Therefore it is also not necessary to cover such ends of yarns or to incorporate them into other material. By braiding is meant preferably extending diagonally across and below.

In this way the disadvantages of conventional stents produced according to a braiding technology and which are formed by a plurality of single or multi-stranded wires or wires are overcome, in which, after the production process, there are several cutting points and cutting edges. cutting, obtuse or sharp, of open wire ends, which require further treatment by coating, soldering, welding or lining, in order to prevent its traumatic effect.

the tubular implant can a tubular structure as well as

According to the invention, it is characterized by having radially compressible and expandable, axially flexible. In the unloaded state, ie without the action of external radial forces, the stent has a radially uniform tubular shape. Preferably, the implant may be flexible in the radial and axial directions.

Advantageously, the implant according to the invention may be formed by wires, which are single stranded wires. Monofilament wires (monofilaments) may have a diameter of 30 pm to 2 mm, in particular from 70 pm to 500 pm. In improvement, the

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<td colspan="2">braided implant is formed by a</td><td>single</td><td>thread</td><td>, this is a</td>

so-called continuous thread. A self-expanding stent formed of a particularly unique monofilament has a mesh-like braid structure.

In another particular embodiment of the invention, the implant braid may be formed by two parallel monofilaments (double strand) which preferably extend in the opposite direction, and preferably also when forming the braid from a single continuous wire.

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At the ends of the implant, the filaments may be bent, in particular curved or serpentine shaped. Preferably, the wire ends, in particular the two ends of the single wire, may lie on the coating plane or side surface of the tubular braid. The yarn ends, in particular all yarn ends, may furthermore lie in their coil next to each other and preferably point in opposite directions.

It may be advantageous for the wire zones to be bent at least at one end of the tube and to be spiraled back into the braid plane. The yarn zones may be bent at least at one end of the pipe, in particular at one end of the pipe, forming a half turn and be led back into the same spiral. The yarn zones are recessed at least at one end of the pipe, in particular at one end of the pipe, at an angle of 60 ° to 120 °, in particular by approximately 90 °, and in a downwardly extending spiral. The yarn zones are bent by 150 ° to 300 °, in particular approximately 270 °, at least at one end of the tube, in particular at one end of the tube, in the form of a crisscrossing loop and are led back into a spiral extending into the opposite way.

According to the invention, at least one end of the pipe, in particular at one end of the pipe, alternately, a yarn zone is bent by 60 ° to 120 ° and a yarn zone of the same spiral is bent by 150 ° to 300 °. as the intersecting loop, and the interlaced wire is led back into the returning and directly connecting spiral and the only angularly bent wire is led back into the subsequent parallel returning spiral. An example of such an embodiment is shown in the attached figure 4.

The tubular implant according to the invention may further be characterized in that it is shaped in the form of a grid and has, in the relaxed state, a mesh opening of 0.5 to 8 mm, in particular from 2 to 5 mm. In this case the wire crossing angles may be greater than 45 °, in particular from 70 ° to 150 °, preferably from 90 ° to 120 °.

In a preferred embodiment, in the braid of the implant according to the invention, each spiral is formed by at least two wires, in particular two wires, parallel to each other. In particular, at one end of the stent, in the case of an even number of strands of a spiral, respectively two strands side by side extend in the opposite direction. An example of such an embodiment is shown in the attached figure 5.

According to the invention, in one embodiment, the braid structure may have a 1 over 1 yarn conduction below 1. In another embodiment, the braid structure may have a 2 over 1 yarn conduction. 2, 2 below 2. Advantageously, in each spiral direction, 4 to 16, in particular 6 to 12 spirals, may be provided with respect to the cross section of the stent.

According to the invention, the tubular implant may be configured with radially uniform diameter. In a particular embodiment of the invention, the tubular implant may be narrowed at the end, i.e. smaller in diameter at the end. A narrowing of the stent of this type may be convenient for the purpose of filtration, for example in blood flow. In another preferred embodiment of the invention, the tubular implant may be enlarged at the end in the relaxed state, i.e. at least at one, preferably at both ends, a larger diameter than at the mid-zone. Such radial dilatation may be convenient to prevent dislocation after stent insertion.

In the case of the tubular implant according to the invention, at least one end of the implant may be configured to radially diverge. In other words, in one embodiment of the invention, one end of the tubular implant may be enlarged. In another embodiment of the invention, both ends of the tubular implant may be flared. Advantageously, the transition from the linear part of the implant to the divergent end may be continuous. Such a flare in diameter can be funnel shaped or tulip shaped.

In the case of the implant according to the invention, the biocompatible material may be metallic material. Typical examples are metallic filaments in titanium, titanium alloys, medical stainless steel such as Cr-Ni steels, W1.4310, Elgiloy®, Phynox®, iridium or metal oxide alloys. In addition, so-called shape memory metals such as Nitinol® may be considered.

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

In a particular embodiment of the invention, the biocompatible material may be a composite of different materials, in particular a composite material. Typical examples are mixed polymers, two-component monofilaments such as core / shell structure monofilaments, metal / polymer composite materials, in particular with metal matrix, as well as polymer coated metals. 0 The stent yarn material may have a metal surface coating, particularly when the yarn material is a polymer.

Numerous filament modifications may be used, as is appropriate for the intended application purpose. For example structured monofilaments, hollow capillary monofilaments, monolayer coated or multilayer coated monofilaments. Thus, the monofilament wires may have a structured cross-section, for example a star-shaped cross-section or a cross-section with a core / sheath structure.

The filament material used in accordance with the invention may be in a wide range of yarn thicknesses and yarn thicknesses (filament diameters). In the case of metal wires, diameters of 10 - 800 pm, in particular 30 diameters of 30 - 300 pm, and in the case of polymeric filaments, - 1000 pm, in particular 50 - 500 pm, are preferred.

In one embodiment of the invention, the biocompatible may be non-absorbable. In another embodiment of the invention, the biocompatible material may be less partially bioresorbable. In yet another embodiment of the invention, the completely bioresorbable biocompatible material.

material way of being by the way of can be

Advantageously, for tubular implant braiding, it has a high resistance to 100 N / mm² and / or a high modulus of 500 N / mm².

formation of the structure of the monofilaments can pull, in the range above elasticity, in the range above

The tubular implant of the invention may advantageously be characterized by being elastic and / or plastic. The elastic and / or plastic properties are based on the combination according to the invention of monofilament and braid structure.

In improvement, in the case of the tubular implant, the originally open-pored braid structure may be at least partially covered by a cover on the inner side and / or the outer side. In another embodiment, the originally open-pored braid structure may be at least partially covered by a coating on the inner side and / or the outer side. As a coating materials with elastic and / or plastic properties may advantageously be used.

A coating may completely embed the implant according to the invention. Alternatively, only certain parts of the implant, for example one or both ends, may be provided with a coating. The coating may cover only the material of the yarns so that the diamond-shaped openings of the braid are uncovered. The coating may also close the implant wall, particularly in the case of an elastic coating material. 0 The coating may be designed in the form of a so-called covering, with a preformed shell or film being applied to the tubular implant and thereby coated on the inside and / or outside. In another procedure, a coating is processed as the so-called coating, with the structural elements of the tubular implant firmly and physically and chemically bonding with a coating material. The coating material may be resorbable.

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

Advantageously, upon improvement, the implant according to the invention may be provided with at least one additive. The additive may in particular be a pharmacologically active substance. Examples of such additives include antithrombogenicity enhancing agents such as hirudin, prostacyclin, heparin. In the use of the implant according to the invention as a drug delivery vehicle for the release of active substances, additives may be added as anticancer agents, for example Taxol®, Thalodmide®. In another embodiment, the additive may be a radiographic marker. In particular, a coating or covering of the wire material may be configured for a drug delivery.

In a special embodiment, the additive may be live cells.

Advantageously, additives may be introduced into the implant according to the invention with the aid of coating technologies. Corresponding to the selection of the active substances and the coating process, it is possible to dope the additives on the surface and / or incorporate them into the polymer matrix. Thus, a release of one or more added active substances may be controlled by the degradation behavior and / or the resorption behavior of the polymeric material used.

The subject of the disclosure is also a process for producing a tubular implant from monofilament biocompatible material by means of textile braiding processes for forming a flexible tubular braid with a closed structure at the ends. For forming the tubular implant according to the invention, the braiding may advantageously be carried out over a mandrel. In a preferred embodiment, the braiding takes place mechanically, in particular automatically. The raw braid may be subjected to post-molding, heat treatment (annealing), coating, covering, coating or an optional combination of such treatments. Preferably, the raw braid for the tubular implant may be subjected to heat post-treatment.

The advantage of the production process according to the invention is that an atraumatic, distal and proximally closed braid construction is formed. Thus, lining of the stent ends as well as similar posttreatment steps become unnecessary.

Advantageously, a tubular implant according to the invention is suitable for use in the treatment of defective and pathologically altered sites, hollow organs, human medicine and veterinary medicine. Examples include malignant and benign obstructions, stenosis, vascular dilatation (aneurysms), and hollow organ damage. Typical application areas for stents according to the invention are blood vessels, esophagus, trachea, duodenum, colon and other parts of the digestive system, as well as urinary and ureteric pathways. Particularly advantageously, the tubular implant according to the invention may find use in hollow organs in the vascular, gastrointestinal, tracheobronchial and / or urethral area.

The tubular implant according to the invention is suitable for supporting and / or holding open a hollow human or animal organ for a certain period of time or permanently. This period of time depends on the material selected and can be tailored exactly to medical requirements. With the implant according to the invention mechanical and physiological requirements such as diameter, return force, compression force and flexibility can also be adjusted very precisely.

For practical application, the tubular implant according to the invention may be compressed with commercial catheters, delivered to the treatment site and positioned in situ with standard delivery systems. Due to its structure, the tubular implant according to the invention is self-expanding and is pressed with a correspondingly selected return force against the hollow organ to be treated.

In the following, the present invention will be explained by describing special embodiments based on examples and with reference to the accompanying drawings. In these embodiments, the individual features of the invention may be embodied individually or in combination with other features. One particular embodiment described is for explanation and better understanding only and is not to be construed in any way as a restriction.

Brief Description of the Figures

Figure 1 shows an end section of an uncompressed tubular stent. Arrows indicate possibilities of displacement of the monofilaments in the braid structure of the tubular implant according to the invention. Α is referred to as the braid yarn crossing angle. At the end of the stent, the monofilaments are bent and looped in the same spiral.

Figure 2 shows the stent according to figure 1 radially compressed and axially dilated. The arrows indicate the action of the compressive force.

Figure 3 shows a complete tubular stent formed with divergent ends on both sides, i.e. tulip-shaped flares at the distal and proximal ends. This embodiment is described in Example 1. The two ends of the tube show a different lead back in the coating plane of the tubular braid. The braid consists of a single monofilament yarn. The two non-visible ends of the yarn, which may be linked together, are on the side surface of the braid.

Figure 4 shows, in one embodiment, the conduction of the filament at the end of the braided stent, in particular at a (upper) end of the stent according to figure 3. The interlaces can be clearly seen, so that at the end it is not visible. protrude no wire-free ends. At the end of the tube alternate zones of intertwined wires of

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at another (lower) end of the stent according to figure 3. Also in this case, loop-shaped wire loops can be seen, so that no wire-free ends protrude at the end.

In all figures, respectively two monofilaments are conducted in pairs in the braided coils, which is preferred.

Example 1

Stent for the area of ​​the esophagus / trachea wire material used is a polyethylene terephthalate (PET) polyester monofilament with a filament diameter of 0.3 mm. The braid was formed with a wire crossing angle of 110 ° over an 18 mm diameter mandrel. The ends of the stent are radially divergent on both sides. The diameter of the stent end is 24 mm. See in this respect Figure 3.

Example 2

Stent for the area of ​​the biliary duet wire material used is a PL-LA polylactic acid monofilament with a filament diameter of 0.3 mm. The braid was formed with a 100 ° yarn crossing angle over a mandrel with a diameter of 8 mm. The stent has a constant lumen, that is, the ends of the stent are not divergently configured, and have a diameter of 8 mm.

Example 3

Stent for the colon area The wire material used is a stainless steel wire type W 1.4310, with a diameter of 0.15 mm. The braid was formed with a 90 ° yarn crossing angle over a mandrel with a diameter of 22 mm. The stent is configured radially divergent on one side. The diameter is 28 mm at the end of the stent.

Production of the implant according to the invention, in particular stenting, is possible through mechanical braiding. In a preferred embodiment, a single wire, in particular monofilament, is placed in parallel and longitudinally oriented loops in tubular arrangement. These loops of respectively two wires parallel to each other are simultaneously twisted alternately to the right and to the left and twisted together, resulting in a tube or flexible tube twisting, twisting spirals on the right and to the left, which is then fixed, in particular thermally fixed.

Lisbon, September 30, 2011

CLAIMS