WO2009077845A2

WO2009077845A2 - Support implant, in particular a stent, and implantation catheter for the support implant

Info

Publication number: WO2009077845A2
Application number: PCT/IB2008/003497
Authority: WO
Inventors: Brigitte Walch
Original assignee: Welldone Weartec N.V.
Priority date: 2007-12-14
Filing date: 2008-12-15
Publication date: 2009-06-25
Also published as: WO2009077845A3

Abstract

The invention relates to a support implant (11) for supporting a tubular body part, in particular a stent for supporting a blood vessel. The support element has a spiral element (17), which is coiled about a virtual axis. This coiled element is a strip element (12), the width thereof being greater than the thickness thereof, and which is wound into a coiled strip element (17). The width of the strip element (12) is oriented in the direction of the axis and the thickness thereof is oriented perpendicular to the direction of the axis. The strip element (12) is expediently manufactured as a spring and has a perforation (13), the holes thereof penetrating the strip element (12) in the direction of the thickness. Said holes may contain active ingredient depots. The coiled strip element (17) advantageously has sections (15a, 15b), which are twisted opposite to one another. The support implant particularly advantageously has an inner lip (40) and an outer lip (41), wherein the rotational directions of coils lying one above another oppose one another. This is the double coil strip spring.

Description

Support implant, in particular stent, and implantation catheter for the support implant

Field of the invention

The present invention relates to a supporting implant, in particular a stent and an implantation catheter according to the preambles of the independent claims.

State of the art

Origin of stent development

Since the 1980s, a large number of supporting implants have been developed to combat arterial diseases or vascular diseases (deposits, venous stasis, etc.). Most are grouped under the term stents. Nowadays implantation of stents is a routine operation with a very high success rate. The implantation of stents can permanently solve or alleviate the patient's problems. There developed a large market, starting from the USA, significantly promoted by the Bosten Scientific, which registered numerous patents on different types of stents. In addition, there are recent applications from Europe, especially for special alloys, which are biodegradable within a period of 1 - 2 years.

As stents, wire spirals were used from the beginning to widen and stabilize the vessel walls. In addition to the wire spirals also laterally open-ended tubes (similar to a tubular screen) or wire mesh were used, which are partly made of fine wire wool. A special form of a stent is a diamond-shaped tube which is open from the side and can be expanded in the diameter by longitudinal compression. With the exception of the latter stent, the aforementioned tubular implants are flexible in the longitudinal direction.

The various types of stents, each with specific advantages and disadvantages, offer the surgeon a choice from which he can select the appropriate model for the respective application. Important features of the stents are both the longitudinal flexibility and the properties that allow the small-diameter implant to be able to be introduced into the vessel full of deposits and, after successful installation, to be able to expand to the desired opening diameter of the vessel. To insert a stent into a vessel, a catheter is used on which the stent is mounted prior to surgery.

There are numerous patents which describe solutions for agreeing the various conflicting design requirements for a stent in the operation. Such requirements are:

The wire spirals must be kept at an even distance.

Sharp ends and tips must be avoided in order to injure the vessels

(by poking / cutting) to prevent. - The mounted on the catheter support implant must mounted on the catheter as possible have a diameter that is significantly smaller than the final desired

Passage opening. Only then can it be introduced into a vessel narrowed with deposits.

Since the course of a vessel is often curved, it must be possible to bend a stent mounted on a catheter as long as possible in the longitudinal direction, so that stresses and

Pressure on the vessel can be kept low.

The stent should not break or break. Such breakages can be pointed and sharp-edged and therefore injure a vessel.

Spirals and tube-like stents should experience no twisting (swirl) in the longitudinal direction when expanding to the final diameter, as this could also twist the vessels and thereby pinch off.

In addition, it must be ensured that the expansion to the nominal diameter is uniform everywhere, which with the frequently used balloons mounted under the

Stent is not always reliable to reach. - When removing the implant catheter, do not allow uneven longitudinal compression or distortion of the stent.

Also desirable is the use of a longer stent, greater than 100 mm (for peripheral

Applications, e.g. in femoral vessels). In general, the stents which are customary today can not be used without problems for use in longer, peripheral vessel sections because of the introduction problems. They must be implanted in sections. In particular, problems arise at the crossing points, because there the

Vascular wall can be injured by these kinks. These inflammations, which frequently occur locally at the kinks, considerably impair the success of the operation because they can lead to swelling and renewed narrowing of the vessels. In order to support the healing of the injuries so-called "drug-eluting stents" were developed, which are coated on the surface with healing-promoting substances.

The design requirements mentioned above have not yet been realized in a stent at the same time, so the surgeon must choose between the different stents, for example: The diamond-shaped stents are very well expandable but not flexible. The spirals with side loops expand less well, but are flexible. The tubes made of wire wool are flexible but hardly expandable. In general, the stents customary today must be implanted in sections for use in longer vessel sections.

Also, the choice of materials used is difficult, since the requirements were very contradictory from the beginning. Namely, the material should be - biocompatible or biodegradable, have high strength and toughness for the spring force (seif expanding) and plastically lasting flexibility.

The usual metallic materials contain chromium and nickel. These materials are chemically resistant, tough but not solid. As alternatives, cobalt-chrome alloys, tantalum alloys have been developed, as well as special forms such as memory alloys. These stents are chemically resistant, tough and have a higher strength than CrNi alloys in the body for a long time. The problem of the aforementioned metallic stents, however, is that they are perceived in the organism as a foreign body and, especially if they are implanted in moving areas, even after years still allergies and inflammation can trigger. For this reason, biodegradable stents have been developed in the past, e.g. made of magnesium.

The implants must be clinically pure and therefore have stainless surfaces. The usual stainless materials, however, always contain chromium and nickel or even nickel-based alloys. The biological compatibility of such materials with a long residence time in the body is difficult to estimate. In addition, requirements from the manufacturing technology of the implants must be considered. Fine wire meshes or spirals must be produced by multiple deformation (wire drawing by drawing dies) and necessarily require a heat treatment and recrystallization. A material alloy can only be chosen insofar as a sufficient deformation possibility is given physically. Even more difficult is the tube production of difficult to deform materials, such as magnesium. As a stent form, therefore, the production of a tube was designed with eg 5 mm diameter. In this tube laterally a diamond-shaped network is cut by laser, so that the resulting pipe network is expandable in diameter and length. It is then not flexible.

Especially interesting are materials without hygienic surface problems, which biodegrade within 1 to 2 years. Such are e.g. Magnesium alloys. The spring properties of the previously known biodegradable alloys, however, are lower compared to high-strength spring materials. ('Biocorrosion of Magnesium Alloys', Heublein et al., Heart 2003 / 'Updates on Bioabsorbable Stents' Heartwire, May 2007 / Internal Medicine Report June 2007 W. Kuznar New Stent Designed to Combat Stent Trombosis)

Stents made of plastic (eg PTFE) have the advantage of being biologically well tolerated. They are also limited deformable, so flexible. However, they are permanently stored as foreign bodies, as well as chromium / cobalt / nickel-metal alloys, and can therefore lead to medical complications. As stents of biodegradable material, poly (L-lactose) acid / PLLA has been developed (Zilberman et al., "Protein-loaded Bioresorbable Fibers and Expandable Stents: Mechanical properties and protein release" Journal of Biomedical Material Research Volume 69B Dec. 1996 / Sharkawi et al., Journal of Pharmaceutical Science Vol. 96 P. 2829 - 2837, Aug. 2007 'Intravascular bioresorbable polymeric stents: A potential alternative to current drug eluting metal stents' / Bünger et al., Vascular surgery 2, Feb 2008 p 99 'Temporary implants for endovascular application'). The mechanical properties are unsatisfactory compared to metal stents, it was therefore attempted to produce by admixing composite materials with higher elastic characteristics in order to achieve a reliable self-opening, which also prevents resealing by spring-elastic mobility, when the implanted stent under body movements, especially in peripheral applications, must remain effective. This was also the usual method in plastic technology of fiber-reinforced materials High-strength glass / ceramic / carbon fibers result in mechanically high-quality composite materials, but the technically usual, cut fibers do not effect. (Slivka MA, Chu CC et al., Bk> Absorbable Composite Materials, Jounal Biomedical Materials Sep. 1997 P. 469-77) absorbable particles, possibly even dangerous long-term effects (a kind of asbestosis).

Apart from the biodegradable stents, all stents have the problem that they represent foreign bodies to the organism, which are rejected in principle. This can lead to inflammation especially in stitches and incisions, which are common complications in installation positions where the vessels are regularly moved (muscle movement / heart, joint proximity). Particularly critical are the beginning and end of a stent, or transition points between two stents.

To improve healing, so-called "drug-eluting stents" have been developed, which are coated on the surface with healing-promoting substances, and even locally occurring inflammations considerably impair the success of the operation because they can cause swelling and re-constriction of the vessels.

A perforated band-shaped element for a stent is known from WO2005 / 079387. Depending on the application, this band can be used as a coil-like, thread-like, reticulated or differently shaped medication delivery device. A disadvantage of this device is that the coils of the coil-shaped coiled strip twist when expanding in a vessel this. From WO 2007/0484437 wire-Stens are known which have sections in which the wire has alternating left- and right-handed helices. In the transition, the wire is bent perpendicular to the spiral bend. These stents have the disadvantage that they have no recordings for active ingredients and lie very small area on the wall of a vessel. From EP 1 790313 a support implant for controlling the passage width of a gastrointestinal passage is known. This has two spouts into each other, of which the outer spout is formed by a plurality of parallel to each other left-handed rotation and the inner spout by a plurality of parallel to each other clockwise wound wires. A disadvantage of this support implant is that the same direction is present in the helices over the entire length of the implant and therefore the wall of a vessel supported thereby is twisted when the implant is widened. Object of the invention

Starting from this prior art, the invention has for its object to provide a design for a support implant that irritates the supported tissue as little as possible in the implanted state. A further object is, if the support implant is biodegradable, to be able to locally influence the degradation of the implant material during its lifetime by chemical means. In particular, it is an object to provide a support implant, in particular a stent, which does not twist when inserting the stent into a vessel, when opening the band spring, this vessel. Another objective is to propose an implantation catheter for introducing such a stent. Another object is to provide a longer support implant, in particular a stent, flexible in the longitudinal direction, without kinks or denominations.

description

The objects are achieved by the subject matters of the independent claims.

A support implant according to the invention may be a stent, i. a support implant supporting the wall of a blood vessel (artery or vein), or a supporting implant supporting the bone of a long bone from the inside. The support implant has a helically shaped element around a virtual axis in the manner of known stents. This coiled element is a band element whose width is directed in the direction of the axis and whose thickness is perpendicular to the direction of the axis. The band element is advantageously a spring, so that it can be turned down against the spring force reducing the radius and jumps up in the cavity by the spring force and presses against the wall of the cavity. Such a helical band element with spring character is often called helical band spring in this description.

Such a belt element has the advantages that it may have perforations, that it may have a low material thickness and therefore can be uniformly degraded when the material is degradable and that it presses flat against the wall of the cavity. Thanks to flat pressing, the support surface is enlarged in comparison to stents with a round cross-section and the local irritation is thereby reduced.

The helical strip spring, in contrast to wire springs have perforations (round holes, slots, etc.). These perforations can be made by fine blanking, laser cutting, etc., and can be used for various tasks: A first possibility is to accommodate differently thick microdots in these perforations. The different thickness microdepots make it possible to predict the dissolution or delivery time desired for a particular pharmaceutical, such as anti-inflammatory agents sirolimus, ABT-578, etc. This is of great advantage, in particular with biodegradable stents, over the currently used surface layer of pharmaceuticals in the case of wire stents. In these wire stents, a surface layer of drugs is produced by immersion in an appropriate solution. Thus, the entire wire spiral is surrounded with this drug film. Therefore, before the stent material can be degraded, the pharmaceutical surface must first disappear completely. When Stent Zerf all then left fragments, which in turn to

Can cause inflammation and injury. There is then no more drug layer available to counteract these inflammations. Pain and narrowing of the vessels can occur again.

In contrast, pharmaceuticals can be accommodated in the perforations in the inventive helical band spring. The drugs with targeted residence time and healing support can be selected and incorporated into the perforation so that any inflammation that may occur during stent disintegration does not even occur. After insertion of the stent, the stent rapidly engrafts with the vascular tissue, i. The stent is enclosed inside and outside with tissue. Therefore, the properly selected drugs along with the perforated stent fragments remain in the tissue until everything is broken down. Consequence: No pain, no renewed constriction of the vessels.

Also, micro-depots of chemically active substances may be placed in the perforations that can control (accelerate or decelerate) the degradation process of the biodegradable support implant of the helical ribbon spring sections: oxidation or salt formation may be controlled at both the surface of the helical ribbon spring and at the soldered turning regions ,

Since the micro-depots are housed in the perforations, the surfaces of the tape can be provided with a biocompatible coating. This can greatly reduce the risk of an endogenous defense reaction to the metal surface immediately after surgery. Perforated perforation holes can facilitate the biological connection between the vessel wall and the interior and allow an excellent process of adhesion and healing. The support implant according to the invention has two or more sections, each with a coiled band element, wherein in successive sections, the directions of rotation of the helices are opposite to each other. This has the advantage that the rotation during expansion of the implant in the vessel there is at most too small and possibly opposite to each other twists, which can easily accommodate the vessel and lead to no significant stress and irritation of the vessel wall.

Particularly preferred stents have a plurality of sections with oppositely coiled band elements in successive sections and in a second layer, the oppositely coiled sections of a second band member. These two coils with opposite direction of rotation on the one hand reduce the mentioned slight rotation of the vessel when expanding the implant, and also lead to a net-like support of the vessel wall. This multi-section net assembly of uncoupled and oppositely coiled inner and outer band members results in a tubular support implant whose cross-section is expandable, which is stretchable and compressible in length, and which can participate in movements and curvatures of the vessel (eg in joints or in joints) Heart muscle area) and which nevertheless supports the vessel wall in a narrow cross grid.

Advantageously, the ends of the sections are welded together, soldered or folded. According to a preferred embodiment of the brazing, holes are provided at the ends of the spiral strip spring sections in order to be able to introduce solder.

When folding, the band is preferably first wound in a single pass directly to the mounting catheter to the right, then folded in the other direction, and further wound to the left. The folded portions (turning portions) of the spiral ribbon spring portions may be locally recrystallized heat-treated (eg, by heating in the laser beam, induction coil, etc.) where the band member is folded to enable crack-free bending and folding. It can be formed by two folds the turning area. This has the advantage that the angles between the longitudinal edges of the band member and the fold fail blunter than when the band member is folded almost at right angles in a fold. The obtuse angles have the advantage over the near-right angles that they cause less irritation and less often injury to the vessel wall. According to a particularly preferred Ausführungsf orm two individual, consisting of at least two right- and left-rotating sections helical coil springs for the representation of a nearly closed flexible stent tube are mirror-inverted wrapped. This has the advantage that a flexible, twist-free double helical band spring is formed. Each spread-apart section advantageously comprises at least one coil and a maximum of three coils, preferably between one and two coils.

With the same purpose, the edges of the coil spring can be rounded. This has the advantage that injury to the vessel can be prevented when inserting the stent. Preferably, therefore, the helical band spring is made by rolling.

In support implants for supporting broken tubular bones from the cavity, a higher stiffness of the support implant is required than with stents. It is therefore proposed that such a support implant forms a surface element consisting of two or more band elements which are joined together along their longitudinal edges, in particular welded together.

In any of the above cases, it may be advantageous if the material of the band member is biodegradable organic. For these materials, the design of the support implant is specially designed, because advantageously the appropriate metal alloys (magnesium-SE base or iron mixed crystal with Al / Si and steel refiners) to high elastic yield strength solidified with appropriate spring force for self-opening and permanent elastic mobility. The design can also be advantageously used for biodegradable polymers (eg PLLA) if they are reinforced, for example, with nanoparticulate carbon short fibers (Maynard et al., Nature Nanotechnology May 2008), since these do not lead to asbestos-like, pathological tissue changes. The design of the support implant is used particularly advantageously for such high-strength elastic CCFC (Curly Carbon Fiber Composites). A plastic deformation is not required for the function, after the biodegradation of the matrix remains a kind of wool from carbon fibers in the neW waxy vascular tissue, which is biochemically harmless as pure carbon and can be slowly absorbed over the years without causing damage in the Conversely, if the carbon wool is provided with a pharmaceutical impregnation prior to being combined with the PLLA matrix, the biocompatible ingrowth into the surrounding tissue may still be aided. The subject matter of the present invention is also an implantation catheter for implantation of a stent according to the invention, which is characterized in that the implantation catheter has an elastically stretchable swelling ring at the tip which can be inflated via a first pressure line running in the catheter interior. The present catheter has the advantage that vessels can be widened in a targeted manner.

Advantageously, an opening is provided at the tip of the catheter, which is in communication with a second pressure line. This makes it possible to use the catheter to introduce medical solutions into the vessel or to aspirate loose material from the artery. Conveniently, the first and second pressure lines are connected to a control device for the catheter. In the control unit pumps and the necessary controls are provided to inflate the Schwellring and relieve resp. pump medical solutions into the vessel or aspirate material out of the vessel.

Preferably, a wedge ring is slidably mounted on the implantation catheter, which is in communication with a cable running in the catheter. With the cable, which is fastened to the wedge ring, the wedge ring on the catheter can be moved back and forth. The wedge ring serves to strip the stent from the catheter. For the cable slots may be provided in the catheter tube at a distance from the Schwellring through which lead the Seilzugbänder from the outside inwards. In addition, grooves may be provided in the catheter wall in which the cable extends longitudinally. The cable thus runs on the one hand in the interior of the catheter in a groove on the inside of the catheter wall and on the other hand on the outside of the catheter wall in a groove on the outside of the catheter wall. By pulling on one of the bands of the cable, the wedge ring can be moved back and forth by pulling on the other cord. In principle, it is conceivable to equip the catheter with a plurality of swelling rings, which are distributed over the length of the catheter.

The subject matter of the present invention is at the same time also a method for implanting a helical-band spring stent, which is characterized in that the helical-band spring is pretensioned (turned up) and fastened on an implantation catheter. In this case, at least at the beginning and at the end of each spring section, the helical band spring is fastened to the implantation catheter. Advantageously, the attachment is done by gluing. Conveniently, the connection points of the left- and right-rotating spring sections and the beginning and the end of the helical band spring are attached to the implantation catheter. The spiral band spring is wound up, stretched Glued state and clamped until the adhesive stops. In this case, even a bias of the stent in the longitudinal direction is possible. Such a bias facilitates withdrawal of the catheter especially in curved vessels.

Advantageously, the implantation catheter with the glued spring ends and

Turned areas between the right and left rotating sections coated with a lubricant before implantation. The lubricant may be mixed with a solvent which dissolves the adhesive at a predetermined interval (as desired by the surgeon). The lubricant containing the solvent must be distributed on the catheter just before it enters the vessel. This handling is made easier for the surgeon by a tear-open cartridge in the catheter package.

The invention will be described in more detail with reference to FIGS. The same reference numerals are used in the figures for the same parts. It shows:

FIG. 1a shows a simple helical band stent made of a helical band made of resilient material; FIG.

FIG. 1b shows a simple spiral band stent made of a perforated spiral band; FIG.

2 shows a first embodiment of a stent according to the invention in the form of a

Spiral band spring with left- and right-handed spiral band spring sections, wherein the spiral band spring is folded in the turning areas;

Fig. 3 shows a second embodiment of a stent according to the invention in the form of a

Spiral band spring with left and right-handed spiral band spring sections, in the turning areas of which the ends of adjacent coil spring coil forming sections are welded or soldered together;

4 shows a third embodiment of a stent in the form of a helical strip spring with left- and right-handed spiral-band spring sections, in whose turning regions the helical strip spring is folded twice;

5 shows a fourth embodiment of a stent in the form of a double

Spiral band spring of two spiral band springs according to Fig. 2;

6 shows a fifth embodiment of a stent in the form of a double

Spiral band spring of two helical band springs according to FIG. 3;

7 shows a sixth embodiment of a stent in the form of a double stent. Spiral band spring of two spiral band springs according to Fig. 4; Fig. 8 shows a portion of a stent or bone support implant in which the longitudinal edges of adjacent helical band springs are welded together. 9 shows a longitudinal section through an implantation catheter, with enclosing

Wedge ring with cables in front of the widened swelling ring; 10 shows a cross section through the implantation catheter before the displaceable

Keilring Fig. 11 shows a cross section through the implantation catheter and the displaceable

Wedge ring; 12 shows a section through the wedge ring in the longitudinal direction of the catheter (detail of FIG. 9); FIG. 13 shows the section through the wedge ring shown in FIG

Wedged ring is in a retracted position and the stent is still on the

Catheter is attached and coated with a lubricating gel layer.

The support implant, or the stent according to FIG. 1a, consists of a helical band spring 17, which is wound in a cylindrical fashion from a band element 12. The band shape of the band member 12 allows the production of perforations in the band member for better connection of the vessel wall and the interior of the vessel, but also for receiving chemically active substances. A helical band spring with holes therein is shown in FIG. The band element is helically wound and may have a perforation or perforation. In this case, the flat sides of the band member 12 to the outside respectively. inside and the perforation penetrates this band element 12 from the outside inwards. Although in the following it is always assumed that perforated spiral band springs are used, in each of the cases cited, both the characteristic of the spring properties and the characteristic of the perforation can be missing.

According to a first embodiment, the support implant consists of a helical band spring 17, which is constructed alternately from left and right rotating sections 15a and 15b. In FIG. 2, such a helical band spring 17 is shown by way of example from FIG. 2 of left-handed sections 15a and a right-handed section 15b. In this case, one end 21 of the first portion 15a is fixedly connected to the beginning 22 of the second portion 15b. The end 23 of the second section 15b is in turn connected to the beginning (24) of the third section 15a. In principle, any number of spiral strip spring sections can be lined up in such a way To form stents of different lengths. The stent according to FIG. 2 can be obtained by first winding a band element 12 around the left, folding it around (turning area 20a), wound around it to the right, folded around (turning area 20b), folded over and then wound up again to the left.

A metal strip used for spring manufacture may be solidified and brittle by deformation over its entire length. So that no cracks or breakages occur during folding, the material can be heat treated locally, so that a crack-free Umfalz is possible. The turning areas are therefore preferably somewhat softer and tougher, so that the risk of cracking is reduced. The solidified sections between the turning areas, however, are preferably equipped with high spring force. In addition to the fold, the two superimposed regions of the band element 12 can also be welded or soldered together.

The individual sections 15a, 15b have perforations 13. In the turning areas 20a, b, these perforations may be missing as shown. But the spring band can also be perforated throughout (Figure 4), so that the turning areas are also perforated. The perforations 13 may serve to accommodate drug microdeposits and / or chemicals.

The embodiment of Figure 3 differs from that of Figure 2 in that the individual helical band spring portions are formed of separate helical band springs, the ends of which are connected to each other at the turning portions 30a, b by soldering or welding.

The embodiment according to FIG. 4 differs from the exemplary embodiment according to FIG. 2 in that the helical band spring 17 is likewise wound and folded from a band element 12, at which point it is folded twice at the turning regions 20a, b. This results in less sharp corners after the fold line.

FIG. 5 shows a preferred embodiment of a stent, which consists of two helical band springs 17 wound in mirror-inverted fashion. Each helical band spring 17 in turn consists of left- and right-handed helical band spring portions 15a and 15b. Analogously to the embodiment of FIG. 2, the left- and right-rotating spring sections 15a, 15b are made of a continuous metal strip 12, which is folded over at the turning areas 20a, b. The folded turning areas are opposite each other. A first helical band spring 17 forms an inner sleeve 40, a second helical band spring forms an outer sleeve 41. Both sleeves 40, 41 together form a largely closed support tube (stent), which remains flexible.

The stent according to FIG. 6 differs from that of FIG. 5 only in that the ends of the band elements of adjacent helical band edge sections are connected to one another by soldering (soldering points 30 a, b).

The stent according to FIG. 7 differs from that of FIG. 5 only in that the band element is turned between two adjacent spiral strip spring sections by double folding. The inner and outer spout are here shifted from each other to distinguish the individual coil springs 17 better from each other.

For example, the two spouts 40, 41 may be interconnected at the ends of the tubular stent formed therethrough. It may also be the outer spout directly in connection to the inner spout from a wound by both spigot band element 12 to be wound.

FIG. 8 shows a bundle of helical band springs 17, which are wound so tightly against one another in sections desired by the surgeon that the edges are adjacent

Band members 12 can be welded together (e.g., by laser welding). The stiffening achieved thereby allows the support, for example, of fragments of a long bone from the inside. The sections adjoining such a stiffened section can remain flexible and, if necessary, be adapted to a curvature of a long bone. Such a rigid tube can also be achieved by a single band member 12, which is wound so tightly that the longitudinal edges 25,26 of the band member 12 abut each other in the coil spring 17. The existing perforation also allows the introduction of active ingredients for healing promotion and / or degradation control of the biodegradable material of the support implant in this use of the support implant.

Figures 5, 6 and 7 show the preferred embodiments for stents, consisting of two superimposed wound coil springs 17, which form an inner spout 40 and an outer spout 41, so that in each case two oppositely wound Wechselbandfederabschnitte 15a, 15b are superimposed. Each helical band spring 17 consists of at least 2 to 3 left and right-handed spiral band spring portions 15a, 15b. Two made in this way Spiral band springs 17, which are wound mirror-inverted, represent an almost closed, flexible stent tube. This embodiment has the advantage that the vessel wall is widened and supported uniformly everywhere. The turns of these spiral band springs 17 prevent the penetration of the remaining deposits during movement of the vessels. Such stents have the advantage that they are largely symmetrical and transmit symmetrical forces during expansion of the vessel on this. In addition, the stent is prestressed in the radial and longitudinal directions, as well as transversely and longitudinally flexible like a millipede. By the left and right rotating spring sections, the stent can be expanded without generating a twist in a vessel (artery).

FIG. 9 shows schematically and in section a front part of a catheter 56. The catheter 56 consists of a flexible tube (not shown) which merges with the front end of the catheter into a rigid catheter head 58 which forms a catheter tip 75. At the catheter tip 75, an inflatable swelling ring 77 is integrally formed or glued. The swelling ring 77 is connected via a first pressure line 73, which is filled with a pressure oil, with a pump not shown in connection. By means of the pump, the swelling ring 77 can be inflated. This inflation of the swelling ring 77 serves to widen a vessel in order to be able to advance the catheter further in this vessel with a subsequently relaxed swelling ring. In the relaxed state, the swelling ring 77 bears against the outer jacket of the catheter tip 75.

On the catheter head 58, a wedge ring 60 is slidably placed, which encloses the implantation catheter. The wedge ring 60 is by means of several cables 67 on the catheter head 58 back and forth movable. The threads or bands 62, 63, 64, 65 of the cables 67 each extend inside the catheter and the delivery tube, from there through a slot 78 in the catheter wall 68 of the catheter head 58 to the outside and outside in longitudinal grooves 61 to the control unit of the catheter 56th Each cable 67 is fixedly connected to the wedge ring 60. By pulling one or the other end of the cables, the wedge ring 60 can be moved forwards or backwards. According to the embodiment shown, a total of four cables are provided. The provision of three or four cables 67 allows the wedge ring to be moved evenly on the catheter head and prevents tilting of the wedge ring on the catheter head. The running edges 66 of the wedge ring 60 run in four grooves 61 extending in the longitudinal direction of the catheter.

In the interior of the catheter tube, a second pressure line 72 extends to the catheter tip 75, where it has an axial opening 70. Through the opening 70 of the pressure line 72, blood plasma or rinsing fluid (possibly with medication) can be introduced into the vessel.

In order for the catheter lumen in which the two pressure lines 73 and 72 are located to be unable to fill with body fluids through the slots 78 in the catheter wall 68, it is possible to fill this lumen with a liquid and continuously squeeze the fluid through the slots 78 ,

Figures 10 and 11 are cross-sections through this catheter head. The cross-section according to FIG. 10 cuts the catheter head perpendicular to the longitudinal extent of the catheter through the slots 78. The view is directed away from the catheter tip 75. The outer circle represents the circumference of the wedge ring 60. The wedge ring 60 sits the catheter head 58 enclosing on this and engages with its running edges 66 in the longitudinal grooves 61 (see Figs.ll and 9). The visible in the figure drawstrings 62,63,64,65 of the cables 67 are guided through the slots 78 and engage from the tip of the catheter forth on the wedge ring. On the back of the wedge ring 60 again attack such drawstrings that together with the front attacking each form a cable 67. In the interior 57 or cavity of the catheter two lines are inserted. The first line 73 serves to supply pressure to the swelling ring and is filled with pressure oil. The second conduit 72 has an axial opening in the catheter tip 75 and may be used to supply the vessel through which the catheter 56 is inserted.

11, the cutting plane is laid through the wedge ring 60, so that the slotted bands of the cable 67 can be seen on the inside of the catheter wall 68. On the outside of the catheter wall 68, the running edges 66 are shown, as shown in the

Longitudinal grooves 61 sit. The running edges 66 may be formed by the bands 62, 63, 64 and 65.

Figures 12 and 13 show a detail section through the catheter head 58. In Figure 12, the wedge ring is shown in an advanced position, as it is approximately after the expansion of the stent by means of the wedge ring. In Figure 13, the wedge ring is shown in a rearward position and the catheter head 58 still carries the tightly wound stent 11. There is a stent 11 with two spouts 40 and 41 shown. About this stent 11, a protective layer of lubricant 55 is placed. In Figures 12 and 13, the second line 72 is shown in section. Of the first line 73, however, only a part of the outer surface is visible. Both lines are in the interior 57 of the catheter 56. The wall 68 of the catheter head 58 has an opening, called slot 78, through which the inner band of the cable 67 is guided to the outside. This slot 78 has a cylindrical sliding surface on the side of the cable 67. The longitudinal grooves 61 terminate in the slots 78, so that the cables 67 are guided in the longitudinal grooves and the slots with the least possible friction.

A stent is placed in a vessel as follows:

An inventive coil spring 17 is biased between the sill ring and the wedge ring wound on the catheter 56 and glued to the ends or optionally at the ends and the turning areas 20 a, b / 30 a, b on the catheter tube 59. In this case, a soluble adhesive is used, which can be dissolved by a predetermined solvent by the operator after a predetermined time. This solvent is in the lubricant that is applied before implantation.

Upon introduction into the vessel, the swelling ring can be pressurized and enlarged via the pressure feed line 73 running inside the catheter in order to stretch the vessel and possibly displace protruding deposits. Spiky particles protruding into the blood stream may be broken off and advanced during introduction or sucked through the pressure line 72. Where the push through stubborn deposits is not immediately possible, the swelling ring 77 can be made smaller and pushed through between the deposits. Subsequently, this constricted area of the vessel can be widened and the stent introduced.

Undesirable particles in the blood can be sucked off with the pressure feed line 72. If necessary, blood plasma, stored blood or medication can be delivered into the space between the catheter and the point where the vessel is pinched off. If complications occur, this blood supply can be reestablished, if necessary, through the implantation catheter 72.

After insertion and positioning of the catheter 56, the wedge ring 60 can be pulled through the stent from the introducer side. This is for safe opening of the stent and for diameter control. The movement of the wedge ring is done by means of the cables 67th

After the stent sits perfectly, first the wedge ring with the cables 67 is moved back completely behind the stent. Thus, the uniform opening of the spiral coil spring or double helical coil spring (stent) is secured. The swelling ring 77 is then shrunk to the smallest diameter, so that the catheter can be easily pulled out.

The stent according to the invention may also be used in other vascular systems of the body (e.g., lymphatic system, bladder, kidneys, penis and other glandular systems) and in a particular

Form can be used as internal stabilization in tubular fractures. In the latter case, the perforated helical band springs are wound so tightly that the windings lie edge to edge against each other (Figure 8) and can be welded at the edges. This can be made between the turning areas stiff sections, if the stabilization of the bone fracture requires.

Legend:

11 Support implant, stent 55 Lubricant

12 metal band, band member for 56 catheters

Spiral band spring 17 57 Catheter cavity

13 Perforation 58 Catheter head

15a, 15b left-handed and 59 catheter tube right-handed sections of the 60 wedge ring

Spiral band spring 61 grooves in the catheter wall

17 Spiral band element / Wendelba 68 for the 4 running edges of the ndfeder wedge ring

20a, 20b turning portions 62 band of a cable 67 in the heat-treated, folded grooves of the catheter wall

21 End of 1st section 66 Running edges of the wedge ring

22 Beginning of Section 2 67 Cable pull movable on both sides

23 End of 2nd section 68 Catheter wall

24 beginning of the third section 70 orifice of the pipe

25 1. Longitudinal edge of the band member 72nd

12 71 Filling space of the swelling ring 77

26 2. Longitudinal edge of the ribbon element 72 Conduit to the vessel for

12 blood plasma delivery, rinsing,

27 fold line of the band member 12 in the suction

Turning range 20 73 Pressure line to the swelling ring

30a, 30b Turned area soldered or welded for pressure oil

40 inner spout formed by a swelling ring

Spiral band spring 75 conical catheter tip

41 outer, similar grommet, 77 Schwellring mirror-inverted above 78 slots wound in the catheter wall, there are double

Spiral band spring

Claims

claims

1. Support implant (11), in particular stent for supporting a tubular body part, in particular a vessel, which support implant has a band element (12) whose width is greater than its thickness, which band element (12) to a virtual

Axis in coils to a helical band member (17), the width of the band member (12) being directed in the direction of the axis and its thickness perpendicular to the direction of the axis, characterized in that the support implant is divided into two or more sections (15 a, b) is divided, and that in successive sections (15 a, b), the directions of rotation of the helices of the helical band member (17) are opposite to each other.

2. Support implant (11) according to claim 1, characterized in that the band element (12) consists of a spring material.

3. Support implant (11) according to claim 1 or 2, characterized in that the band element (12) at least partially has a perforation (13) whose holes penetrate the band element (12) in the direction of its strength.

4. Support implant according to one of claims 1 to 3, characterized in that the

Spiral band elements (17) of adjacent sections (15a, b) in the transition (20,30) overlap between the two sections.

5. Support implant according to one of claims 1 to 4, characterized in that a first spiral band element (17) an inner spout (40) and a second spiral band element (17) forms an outer spout (41), and that a spiral of the inner spout (17). 40) is surrounded by a helix of the outer spout (41) in the opposite direction of rotation with a first direction of rotation.

6. Support implant according to one of claims 1 to 5, characterized in that one, two or more spiral band elements (17) are joined together along their longitudinal edges, in particular are welded together.

7. Support implant according to one of claims 1 to 6, characterized in that the band element (12) is made of biodegradable materials, the high-strength are elastically formed.

8. Support implant according to one of claims 1 to 7, characterized in that at least a part of the holes of the perforation (13) is filled with an active substance depot, optionally that active substance depots are present with different active substances.

9. Support implant according to one of claims 1 to 8, characterized in that the support implant comprises carbon wool, and at least a portion of the carbon wool is coated with an active substance depot.

10. Support implant according to claim 8 or 9, characterized in that the active substance of the active substance depot has a healing or anti-inflammatory effect on the body part.

11. Support implant according to one of claims 8 to 10, characterized in that the active substance has a degradation of the band member accelerating or retarding effect.

12. Support implant according to one of claims 4 to 11, characterized in that at the ends of the portions (15a, b), the ends (21,22; 23,24) of two band members (12) are soldered or welded together or glued together.

13. Support implant according to one of claims 4 to 11, characterized in that the band element (12) at the transition between two sections (15 a, b) is folded over.

14. Support implant according to claim 13, characterized in that the band element (12) is folded over so that the outline, the successive

- The one longitudinal edge (25), - the fold line (27) and

- The other longitudinal edge (26) of the band member (12) comprises, forms at the folding point obtuse angle.

15. Support implant according to one of claims 4 to 14, characterized in that the edges (25,26) of the band member (12) are rounded.

16. Support implant according to one of claims 4 to 15, characterized in that the band element (12) is rolled.

17. An implantation catheter (56) carrying the support implant (11) according to any one of claims 1 to 15 for implantation of the support implant (11), with a pressure line (72,73) extending in the catheter hub (57).

18. implantation catheter according to claim §7, characterized in that the implantation catheter (56) at the tip (75) in front of the implant (11) has an elastically stretchable swelling ring (77), which via a in the catheter cavity (57) extending first pressure line ( 73) is inflatable.

19. implantation catheter according to claim 17 and 18, characterized in that at the tip (75) of the catheter (56) has an opening (70) is provided which with a second

Pressure line (72) is in communication.

20. Implantation catheter according to claims 18 and 9, characterized in that the first pressure line (73) and the second pressure line (72) and the catheter cavity (57) are connected to a control device for the catheter (56), which controls the pressure for the Pressure lines (72,73) and the catheter cavity (57) controls.

21. Implantation catheter according to one of claims 17 to 20, characterized in that a wedge ring (60) on the implantation catheter (56) is slidably mounted, which communicates with a in the catheter (56) extending cable (67).

22. implantation catheter according to claim 21, characterized in that at a distance from the sill ring (77) slots (78) in the wall (68) of the catheter (56) are provided, through which the cable pull (67) extends from the outside inwards.

23. implantation catheter according to claim 21 and 22, characterized in that on the outside and on the inside of the catheter wall (68) grooves (61) are formed, in which the cable pull (67) extends and the running edges (66) of the wedge ring ( 60).

24. Implantation catheter according to one of claims 17 to 23, characterized in that the helical band member (17) is a helical band spring and is biased on the implantation catheter (56).

25. Implantation catheter according to claim 24, characterized in that the helical strip spring (17) at least at the beginning and at the end of each section (15a, b) on

Catheter tube (59) is glued.

26. implantation catheter according to claim 24 and 25, characterized in that the adhesive can be dissolved with a solvent and the catheter head (58) in the region of the support implant (11) and the support implant (11) prior to implantation with a lubricant gel

(55) coated to contain this solvent.

27. A method for implanting a support implant (11) in a tubular body part, in particular a vessel, characterized in that a support implant (11) according to one of claims 2 to 18 by unscrewing the one or more coiled sections

(15a, b) is biased against the spring force of the helical band spring (17) and is secured in such a stretched state on an implantation catheter (56).

28. The method according to claim 27, characterized in that the beginning and end and optionally turning areas (20a, b / 30a, b) of the helical strip spring (17) are glued.

29. Method according to claim 28, characterized in that the implantation catheter (56) equipped with the support implant (11) is coated in the region of the support implant (11) with a lubricant (55) containing a solvent for dissolving the adhesive.