NL1023389C2 - Forming 3D article used to make blood vessel protheses, by winding two sets of yarns around form with rings of yarn guides around its ends - Google Patents

Abstract

A form (2) with external contours corresponding to the 3D shape of the article to be produced is prepared, rings of yarn guides (14, 18, 20) are provided on each end of the form, a first set of yarns is wound around the form and then a second set of yarns is wound around the form so that they pass under and above the first yarns. A method for forming a 3D hollow article with end edges located in two or more spaced apart planes from a fabric with interlocking yarns, comprises the following steps: (a) preparing a form with external contours substantially corresponding to the chosen 3D shape of the article; (b) applying a ring of yarn guides around each end of the form; (c) winding a first set of yarns around the form; (d) winding a second set of yarns around the form so that they pass under and over the first yarns. Independent claims are also included for the following: (a) Semi-finished product made by this method, used for making a prothesis for placing in a blood vessel; and (b) Blood vessel prothesis made by impregnating the semi-finished product in resin.

Description

H Brief description: Method for forming a three-H, hollow product, product made up of a fabric that intersect with each other's intersecting threads, using this method and H body prosthesis obtained therefrom.

The invention relates to a method for forming a three-dimensional hollow product built up of a fabric from intersecting threads, to a product obtained using this method and to a body vessel prosthesis obtained therefrom.

Modern weaving techniques make it possible to obtain fabrics that meet the most varied requirements. However, the products obtained are always two-dimensional: if one wishes to manufacture a three-dimensional product from such a two-dimensional product, a connecting seam, often disruptive, always results. Furthermore, the design of such products is very limited.

I Seamless three-dimensional products can be manufactured I using the knitting technique. However, this too has limitations: if it is desired to manufacture a product with small dimensions from thin threads with the knitting technique, a product I with large meshes that is limp and has little strength will result.

The invention has for its object to provide a method with the aid of which a seamless three-dimensional product can be obtained and wherein one is highly free in the design thereof. This object is achieved with a method that consists of preparing a shape whose outer contours substantially correspond to the desired three-dimensional shape of the product to be formed, a wreath of wire guides being applied to each of the respective end edges thereof, wraps a first processing step with first, threads running next to each other and between opposite thread guides and wrapping the thus-obtained surface in wires in a second step with second threads also running next to each other, crossing the first threads and alternating above this wrapping and are passed under the first wires.

ΐ 023 3 «o I - 2 - I This method offers many advantages. There is a great deal of freedom in the dimensioning and shaping of the prepared shape which, depending on the desired final three-dimensional contours, can be a shape whose product can simply be slid off, which can be a collapsible shape or a lost shape could be. When the shape is made with convex curves, the first (longitudinal) threads stretched over it will automatically follow the contour of the I curvature and when the shape is one with hollow curves, the first (longitudinal) threads arranged over it will initially 10 lie more or less loosely, but after applying the transverse threads, lay against the surface thereof and also retain this contour in the final product formed. A tubular product with a number of branches can easily be realized.

A much larger number of threads per unit length can be realized with the method according to the invention than is possible with the known weaving or knitting techniques. A very fine-meshed fabric or tubular product can thus be obtained which is, for example, very suitable for filter applications.

Moreover, the advantage is obtained that, in contrast to, for example, knitted products, the end edges of the product obtained do not require H special treatment to prevent unraveling.

H The method according to the invention is eminently suitable for H manufacturing a body vessel prosthesis, in particular a blood vessel prosthesis, or a semi-finished product therefor.

A blood vessel prosthesis formed from porous sheet-like material infused with a hardening plastic is known per se from, for example, US-5,344,444, US-5,464,429, EP-0 521 573, EP-0 617 930 and WO99 / 37243, all with the same inventor like the present one. Such a prosthesis is applied in folded condition around a deployment balloon at the end of a positioning catheter and brought to the desired location via an incision in a body vessel.

The method of placement - via an incision and blood vessels - implies that the diameter of the folded prosthetic package at the end H 35 of the delivery catheter can only be limited; a diameter of approximately 6 mm is typically the maximum value that can still be handled in practice. This leads in particular to problems in the manufacture of prostheses intended to be placed in the aorta - in many cases a barrel diameter of 25 ram or more having to be bridged.

The method according to the invention is eminently suitable for solving these problems, not only because it is possible to work with very fine threads and yet obtain the desired mesh size in a seamless product, but also because it is possible to achieve any desired configuration , also with branches, to realize and to form a seamless whole with very small dimensions.

The preparation of the shape on which the semi-finished product is assembled from the intersecting wires is, since modern diagnosis and X-ray techniques make it possible to obtain an exact image of the body vessel at the location of the prosthesis to be applied, not a single one problem while wrapping such a shape with intersecting wires is a precision work, but, as has been found, it is also feasible. This results in a semi-finished product with superior properties and particularly suitable for the production of a barrel prosthesis soaked with curing plastic that can be folded into very small dimensions.

The method described makes it possible to use wires made of materials with mutually different properties or diameters. As a result, it is possible to give the semi-finished product, in certain places to be selected as desired, special properties, in particular as regards strength and rigidity.

It is also possible to introduce into the fabric threads formed from, or coated with, a therapeutically active substance such as the hisparine or aspirin known per se. This allows a metered release of a medicament and thus also a targeted treatment of the tissue surrounding the final blood vessel prosthesis.

It is also conceivable that spaces are created between adjacent wires during the wrapping of the mold.

The requested exclusive rights extend to the product obtained with the method, in particular a semi-finished product for a blood vessel prosthesis, and also to a blood vessel prosthesis formed from such a semi-finished product.

The invention is explained with reference to the drawing. In the drawing: 1023389 Fig. 1 shows in perspective view a shape suitable for carrying out the method according to the invention; Fig. 2 shows a side view and schematically an installation with the shape according to Fig. 1 placed therein during the execution of the method according to the invention; Fig. 3 shows diagrammatically parts of the ends of the mold according to Fig.

I 1 and 2 with the attachment points for the wires present there; Fig. 4 is a plan view of a portion of the formed, porous, sheet-like material; Fig. 5 shows a perspective view of the obtained semi-finished product.

FIG. 6 is a perspective view of a part of a fabric obtained with an exactly custom-made opening therein.

The figures relate to the case in which the three-dimensional product to be manufactured is the semi-finished product of a blood vessel prosthesis, in particular a prosthesis intended to be placed in the aorta, all as described above.

FIG. 1 shows a winding mold 2 which has the configuration of H a vessel prosthesis known per se as it will be after placing and expanding the prosthesis obtained with the semi-finished mold formed on the mold. The shape 2 consists of the substantially cylindrical main body 4, of which at one H end the long, also cylindrical, pipe 6 and the short H pipe 8. A prosthesis with such a configuration will, after placing H bridge aneurysms formed; the respective branches then protrude into the arteries leading to the legs (the so-called arterie iliaca). An aortic aneurysm that almost always occurs above the branch to the two iliac arteries can be treated in the classical H manner by bridging the weakened part H 30 of the aorta with an artificial blood vessel, which, however, has a very extensive, prolonged and very burdensome intervention for the patient means H. There is therefore a large and still increasing interest in the development of a vessel prosthesis with which the weak spot H can be bridged and which can be brought to the weakened location with the aid of an H 35 catheter and can be moved there be deployed. Such a prosthesis must consist of an H-widened main part and two end parts that closely project into said branching H arteries. The fact that one end part of the H prosthesis is initially shorter than the other has its origin in the manner of placement; after the main part has been placed, an extension piece, which fits closely into the branching artery, is provided on the short end part. Reference is made to EP 0 943 301 with the same inventor as the present one.

The mold 2 is closed at the left-hand end 10 and a ring 14 of thin pins is arranged along its edge boundary 12; such pins are also provided on the right-hand end 16 of the long branch 6 and are designated 18 there; a similar ring of pins 20 is located along the peripheral edge of the right-hand end 22 of the branch 8.

Furthermore, in the mold 2, a central bearing rod 24 is fixed, which protrudes from the left-hand end 10 thereof and which substantially coincides with the rotary longitudinal axis of the mold.

As Fig. 2 shows, the shape 2 can be supported via this bearing rod 24 'in the output shaft of a suitable mechanism 26, only shown schematically, which is received in a post 28 and with the aid of which the shape 2 is arranged stepwise around the axis of the support rod 24 can be rotated.

The method proposed according to the invention is now carried out in such a way that first the shape 2 is wrapped with thin longitudinal wires of the desired thickness, running between one of the pins 14 at the left end and one of the pins 18 and 20 at the right end respectively. and in Fig. 2 partially indicated as a package with the reference numeral 30 for the longitudinal wires that extend between the pins 14 and the pins 18 and indicated with 32 for the longitudinal wires that extend between the pins 14 and the pins 20. As Fig. 3 illustrates for example, a wire 30a is wrapped around a pin 14a and then extends to the pin 18a located on the other side of the mold 2, then returns to the pin 14b located on the left side, is wrapped around it and then runs again to a pin 18b located on the right-hand side. Similarly, the wire package 32 is formed with a wire 32a being drawn at the bottom in Fig. 3, extending between the pins 14c, 14d on the left and the pins 20c, 20d on the right.

Thus, when the entire shape has been developed in the longitudinal direction with wires, the cross-wire package 34 which covers the main part 4, and the cross-wire packages 36 and 38, respectively, are wound around the branches 6 and 8, respectively. For the sake of clarity, these packages are also only partially signed. Here again, the step-by-step support mechanism for the shape 2 facilitates the arrangement of the wires in a cross pattern of which Fig. 4 gives an example I. This figure shows the longitudinal wires 30a-30d; the wires 34a-34e running transversely are then passed below or above the cross wires, so that the shaded intermediate spaces 40 remain that are suitable to be filled with curing plastic. FIG. 4 also shows how it is possible to introduce different threads; the figure shows as an example between the wires 34d and 34e a more or less band-shaped wire 42 which may itself consist of therapeutically active material or which may be doped with a therapeutically active material and dosed to the vessel prosthesis after placement the passing blood or I releases the surrounding tissue.

After the winding has been completed, the pins 14, 18 and 20 are removed and a semi-finished product is easily formed on the mold 2 and can be easily removed from the mold and is shown in Fig. 5, indicated by 44. It comprises the main part 46 which, after being placed in an aorta, will bridge the aneurysm and the two tube parts 48 and 50, respectively, projecting into the respective iliac artery.

Figure 6 shows how with the method according to the invention an opening can be created very easily at one or more predetermined places in the wall of the product formed by the fabric. For this purpose, only the winding of the longitudinal wire package 60 at the desired location, for example 62, needs to be interrupted over a distance d1 25 while the winding of the cross-wire package I 64 there is interrupted over the distance d2 around an opening with dimensions d1 x d2 to obtain.

It will be clear that within the scope of the invention the sequence of winding can be reversed, and thus first the cross threads, and then the longitudinal threads can be applied. Furthermore, the product obtained, even when it is still on the mold, can be subjected to all desired bone effects.

With a product with the mold as described above, the molded product can be pushed off the mold. With other, more complicated configurations, this will not always be possible and then one can for instance use a form that is collapsible or a "lost" form, i.e. a form that is renewed after use, for example by heating, such as on known from the casting technique.

Claims (9)

CLAIMS 1. Method for forming a hollow, three-dimensional product made up of threads intersecting with one another, with end edges lying in at least two spaced apart planes, comprising preparing a shape of which the outer contours in substantially correspond to the desired three-dimensional shape of the product to be formed, affix a wreath of wire guides to each of the respective end edges thereof, wrap the shape in a first processing step with adjacent, first, wires running between opposite wire guides and wraps the thus-obtained surface consisting of wires in a second step with second wires also running next to each other, crossing the first wires and passing through alternately above and below the first wires during this wrapping. j 2. Method as claimed in claim 1, wherein use is made of wires formed from materials with mutually different properties or diameter. 3. A method according to claim 1-2, characterized in that the method is used for manufacturing a body vessel prosthesis or semi-finished product therefor. 4. A method according to claim 3, characterized in that the wrapping of the mold is carried out in such a way that receiving spaces are created at the intersections formed by the wires for receiving a curing plastic. 5. Method as claimed in claim 4, wherein wires or strips are introduced into the semi-finished product which are formed from or coated with a therapeutically active substance. 6. Method as claimed in claims 1-3, wherein a space is left free between adjacent wires during the wrapping of the mold. Product obtained using the method according to one or more of claims 1-6. 8. Semi-finished product for a vessel prosthesis to be placed in a body vessel, consisting of the product according to claim 7. 9. Vessel prosthesis to be placed in a body vessel, obtained by soaking the semi-finished product according to claim 8 with a hardening plastic. 1 023 3 8.0 -βίο. Form for carrying out the method according to claims 1-6, characterized by wreaths of wire guides arranged at or near the edges of their boundary surfaces.