EP2977496B1 - Method for producing a body implant and tool used for that purpose - Google Patents

Description

The present invention relates to a method for producing a body implant, such as a stent, a heart valve frame, a flow diverter, etc, for insertion into the living body. Furthermore, the invention relates to a tool for producing a body implant.

For example, body implants made of nitinol mesh are typically cylindrical or conical or a combination of both. Due to boundary conditions such as Braid angle, number of wires and geometry of the braid and the necessary shaping processes, the possibility of variation is limited.

Conventionally, more complex forms of braids can only be made by elaborate braiding algorithms or by braiding tradeoffs, since it is often not possible to stretch tapered diameters to such an extent that damage-free separation of braid and tool is possible. It would be desirable if the design of the braids could be made with greater flexibility.

US 2004/0 254 633 A1 discloses a method and apparatus for the manufacture of intraluminal implants and a construction that is particularly useful in such methods and devices.

US Pat. No. 3,586,058 discloses hollow bodies and methods of making the same by braiding a core and impregnating with resin.

WO 95/17 997 A describes shaped products made from preforms with tubular braids.

The object of the invention is to provide a novel method for producing a body implant, with which more flexible forms of braids can be produced.

This object is solved by the features of the independent claims. Advantageous developments of the invention are defined in the dependent claims.

According to one aspect, a method of manufacturing a body implant with the steps of claim 1 is provided.

• o Erzeugen eines Geflechts auf einem beliebig geformten Werkzeug,
• o Durchführen einer geeigneten Formgebung des Geflechts, und
• o Separieren des Geflechts vom Werkzeuges.

It is therefore a procedure with the steps:

• o creating a braid on an arbitrarily shaped tool,
• o Performing a suitable shaping of the mesh, and
• o Separate the braid from the tool.

Thus, for example, a mesh with changing diameters can be produced with flexibly selectable braiding angle and number of wires. The generated body implant can thus optimally to the requirement or the application be matched. Thus, in various fields of medical technology, a body implant optimized for the individual patient, a so-called "personalized braid", can be produced.

The term "producing a braid" is to be understood as meaning, in particular, the mechanical as well as the manual production of a braiding, generally braiding.

By performing the shaping is meant a reduction of the stresses that have arisen as a result of the braiding process. When all stresses have been removed, the braid essentially retains its shape. For example, for Nitinol the shaping is typically to be understood as a heat treatment.

The term "separating or removing the braid from the tool" is understood in particular to mean that the tool is separated from the braid. Removal may preferably be carried out by melting due to heat, breaking, dissolution in or by suitable chemical substances, including water and by forming the tool. As a result, the tool is at least damaged and usually can not be reused. In this context, one speaks of a tool that can be used once or of the principle of a "lost form".

Preferably, the step of removing the tool is performed substantially simultaneously with the forming on the braid. This is particularly advantageous if the shaping is carried out by a heat treatment and the heat supply can change the shape of the tool. More preferably, the shape of the tool is changed by the tool, for example, melts, breaks or dissolves.

Advantageous are tools that destroy themselves during the molding process, for example, due to high temperatures or temperature differences. In this case, the destruction may only take place after the shaping has taken place, or the shaping process should take place as planned.

More preferably, the tool has at least one predetermined breaking point.

Preferably, the tool comprises at least a portion of a wax, resin, plastic, such as polyvinyl alcohol, foam, elastomer, glass fiber reinforced plastic, pulp, gypsum, salt, sugar, glue, glass, sand. For example, glass, salts and sand compounds may be suitable for self-destruction.

More preferably, the shaping on the mesh includes a heat treatment.

Preferably, the tool has a destructible portion and a non-destructible portion.

Preferably, the tool has a reusable sheath which can be filled with a fluid to produce the desired shape of the tool and at least partially emptied for removal.

Reusable tools may be, for example, casings that are emptied when removing the tool and can be refilled at a next mesh to be produced. However, reusable tools in the form of a braid or a structure similar to a braid can also be used structured as a tool. In this case, the separation is carried out by pulling or pulling, wherein preferably a cross section of the tool is reduced.

Nitinol or other common metallic wire materials could be used for reusable tools. For so-called casings, all flexible and thin-walled executable materials can be used which can withstand the respective shaping process.

More preferably, the tool is at least partially formed as a braid or mesh-like structure and is claimed for removal to train to reduce the cross-section so that removal is possible.

As an advantageous development, depending on the material, shape or complexity of the braid and the associated treatment method, an opening of the braid may be required. For example, these could be very fine structures that exclude the use of certain tooling materials and thus can not be braided directly on the "lost shape" tool.

In this case, the braid can be opened to replace the original tool with another substantially same shape tool. In this case, the other (second) tool consist of one or more materials that are, for example, chemically dissolvable and / or melted or deformed by low heat input. However, an influence or impairment of the formed braid must be avoided.

The term "opening" is to be understood in particular that the braid is unbound again. An "open" can be understood as a reversal or inverse process for creating a mesh. For example, a textile structure / braid can be opened by braiding it backwards.

Preferably, upon opening, the braiding material or nitinol wire is "held in position". For example, ends can be fixed by means of holding devices, such as grippers or wire, so that only the previous braiding process, namely the creation of the braid, is reversed. The mesh is only opened until it is possible to remove the part of the tool that would not be removable if the mesh was not open.

If the direct generation of the mesh requires at least second shaping, the principle of the "lost form" can also be applied to other shaping processes. An example of the need would be to create undercuts. Ideally come here Combination tools are used, which consist of a destructible and a durable reusable part, wherein the durable part preferably specifies the required final or intermediate shape.

More preferably, the tool has at least one mechanically displaceable region, which is mechanically displaceable by folding, pivoting, turning, etc., in order to change the shape of the tool.

Preferably, the method described above produces a vascular prosthesis, a stent graft, an occluder, a flow diverter, a coil, a heart valve frame, an AAA stent, a thoracic aortic aneurysm (TAA) stent, a gastronenterologic stent, or a peripheral stent. Abdominal aortic aneurysm (BAA), abdominal aortic aneurysm (AAA), or abdominal aortic aneurysm is considered to be an enlargement of the abdominal aorta below the exit of the renal arteries in the anterior-posterior diameter to over 30 mm. Clinically, a distinction is made between asymptomatic, symptomatic and ruptured aneurysms. The asymptomatic (painless) aneurysm is a chance finding. Symptomatic aneurysm is dominated by symptoms and ruptured by circulatory conditions.

According to a further aspect, a tool for producing a body implant is provided by at least partially braiding the tool, wherein the tool has a shape that is at least partially variable such that the tool can be removed if a braid created by braiding the tool is substantially closed and / or the braid, the tool at least partially wrapped and / or undercuts.

Preferably, the shape of the tool is variable by the tool melts, breaks and / or dissolves and / or the tool has at least one predetermined breaking point.

More preferably, the shape of the tool is changeable in that the tool has a reusable casing, which can be filled with a fluid to produce the desired shape of the tool and is at least partially emptied for removal.

Preferably, the tool is at least partially formed as a braid or mesh-like structure.

More preferably, the tool has at least one mechanically displaceable region, which is mechanically displaceable by folding, pivoting, turning, etc., in order to change the shape of the tool.

• Figur 1 zeigt ein Geflecht, das mittels eines geflochtenen Werkzeugs hergestellt wird.
• Figur 2 zeigt ein aus einem Geflecht hergestelltes Körperimplantat mit Hinterschneidungen.
• Figur 3 zeigt das Erzeugen eines Geflechts durch Umflechten eines Werkzeugs und teilweises Rückwärtsflechten zum Entfernen des Werkzeugs.
• Figur 4 zeigt das Entfernen eines ersten Werkzeugs und Einsetzen eines anderen Werkzeugs in ein teilweise geöffnetes Geflecht.
• Figur 5 zeigt das Fertigstellen des Geflechts aus Figur 4.
• Figur 6 zeigt das Erzeugen eines Geflechts und Durchführen einer Formgebung sowie das Einsetzen eines zweiten Geflechts in das erste Geflecht.

The invention will now be explained in more detail with reference to several embodiments with reference to the accompanying drawings.

• FIG. 1 shows a braid that is made by means of a braided tool.
• FIG. 2 shows a made of a braid body implant with undercuts.
• FIG. 3 Figure 3 shows the creation of a braid by braiding a tool and partially braiding it back to remove the tool.
• FIG. 4 shows the removal of a first tool and insertion of another tool in a partially opened braid.
• FIG. 5 shows completion of the braid FIG. 4 ,
• FIG. 6 shows the creation of a braid and performing a shaping and the insertion of a second braid in the first braid.

As in FIG. 1 is shown, a braided tool 52 is provided substantially in the shape of a braid 10 to be produced and the braid 10 is produced by braiding the braided tool 52. Since the braid 10 after completion is substantially closed, ie only has openings 14 at opposite ends and in its central portion has a bulbous portion 16 of larger diameter, the diameter bulbous portion 16 is greater than the diameter of the openings 14, the bulbous portion 16 forms an undercut to prevent the removal of the tool 52.

In order to remove the braided tool 52 from the finished braid 10, tension is applied to the opposite ends of the tool 52 so that the braided tool 52 elongates in length and the cross-section is reduced. In this way, as in FIG. 1 is shown, the cross section of the braided tool 52 is reduced such that the cross section is smaller than that of the openings 14 in order to pull the tool 52 from the openings 14 can.

Such a braided tool 52 may be reused in some circumstances when the reduction in area for removal of the tool 52 from the braid 10 takes place in the elastic region, i. the braided tool 52 returns to the original shape with the bulbous portion 16 when the pulling force on the ends of the tool 52 is removed. However, the braided tool 52 may be a single-use tool if the deformation is outside the elastic range, so that the original shape with the bulbous portion 16 can not be accepted by the braided tool 52.

Such a tool 52, which can be applied even in areas of undercuts and can be removed by a cross-sectional reduction of the finished braid 10, can also in other shapes a mesh 10 are used.

An example of this is in FIG. 2 shown in which a body implant 10 is made of a braid 10 having a pair of branches with an undercut 12. In this way, many complex shapes of a body implant can be produced. It can thus be provided a so-called personalized braid for a patient.

However, the invention is not limited to the application of a braided tool 52, but can also be performed with tools that can be dissolved, for example, by heat. Examples include wax, resin and plastics such as polyphenyl alcohol. In this case, a tool can be removed from the undercuts 12 or a bulbous region 16 by dissolving the tool. For this purpose, for example, heat is applied to bring the tool to melt or dissolve.

Another way to remove the tool from a manufactured mesh 10 is to break the tool, dissolve and / or provided with a predetermined breaking point.

The above-described manner of removing a tool from a finished mesh 10 by reducing the cross-section, melting, breaking or dissolving according to the lost-mold principle may also take place after a first braiding operation and / or after a first shaping and / or heat treatment. For this purpose, as in the Figures 3 and 4 First, a reusable braiding tool 54 is used to make a braid 10.

After weaving back or partially opening the braid 10, the reusable tool 54 is removed from the braid 10 and replaced with a disposable tool 56, as in FIG FIG. 4 is shown. Thereafter, the braiding process is completed and the finished braid 10 is in FIG. 5 shown.

The disposable tool 56 can then be removed from the finished braid 10 by reducing its cross-section, as in FIG FIG. 1 is shown, or the disposable tool 56 is removed by melting, breaking or dissolution of the braid 10.

In the FIGS. 3 to 5 The reference numeral 30 shows a known braiding machine with bobbins 35 for producing the braid 10.

The method described above can also be used with that in the patent DE 10 2012 016 301 B3 described method for producing a body implant, as in FIG. 6 is shown. In this case, after a first heat treatment on a first braid 10, part of the braid 10 is removed and replaced by a second braid 10a, as in FIG FIG. 6c is shown.

The method described above is therefore particularly suitable for producing a vascular prosthesis, stent graft, occluder, flow diverter, coil, heart valve frame, AAA stent, TAA stent, gastroenterological stent or peripheral stent.

After the braids 10 of a body implant 1 can be made very flexible according to the method described above, complex and desired shapes for creating a personalized mesh 10 for a patient can be easily produced. The shaping of the braid 10 is preferably carried out by a heat treatment in order to reduce or substantially eliminate stresses arising in the braid 10.

However, it is also possible to apply a shape memory property, which is used in particular on the material Nitinol. In this case, a metal structure in a so-called martensite structure is provided in the braid 10, which is converted into an austenite structure by raising the temperature by phase transformation. It is extraordinary for Nitinol that this transformation is reversible without plastic defects occurring. The phase transformation thus takes place without diffusion, that is, without the atoms changing places in the lattice structure. In particular, in this diffusionless reversible phase transformation of the austenite into the martensite structure, the atoms adopt an ordered twin arrangement through pure shear deformation.

However, instead of nitinol, a polymer, a biodegradable polymer or tungsten may also be used. In this case, tungsten can increase the radiopacity of the body implant 1. However, so-called markers can increase the radiopacity, which are made of tantalum or gold, for example.

LIST OF REFERENCE NUMBERS

1

body implant

10, 10a

weave

12

undercut

14

opening

16

bulbous area

30

braiding

35

tongue

52

braided tool

54

reusable tool

56

single-use tool

Claims (9)

1. Method for producing a body implant, comprising the steps of:

   providing a tool (52; 54; 56) with a predetermined or predeterminable shape,

   Braiding around a first tool (54) with at least one braiding material and thus creating a braid (10, 10a) at least partly in the shape of the tool (54),

   carrying out a shaping at the braid (10) and

   removing a different tool (52, 56) from the braid (10, 10a), wherein the tool (52, 56) is configured in such a way that the shape of the tool (52, 56) is at least modifiable in such a way that the tool can be removed if the braid (10, 10a) is essentially closed and/or the braid (10, 10a) at least partly encases the tool (52, 56) and/or has undercuts (12),

   characterized in that

   the braid (10) is at least partly unbraided after shaping in order to replace the first tool (54) by another, easily dissolvable and/or easily removable tool (52, 56), and subsequently the braid (10) is braided again essentially in the same manner and/or is replaced by a different braiding material (10a).
2. Method according to one of the previous claims, wherein the shape of the tool (56) is modified by the tool (56) melting, breaking and/or dissolving and/or the tool (56) having at least one predetermined breaking point.
3. Method according to one of the previous claims, wherein the tool (52; 54; 56) has at least one portion of a wax, resin, plastic, preferably polyvinyl alcohol, foam, elastomer, glass-fiber reinforced plastic, cellulose, gypsum, salt, sugar, adhesive, glass, sand.
4. Method according to one of the previous claims, wherein the shaping at the braid (10) includes a heat treatment.
5. Method according to one of the previous claims, wherein the tool (52; 54; 56) has a destructible portion and a non-destructible portion.
6. Method according to one of the previous claims, wherein the tool (54) has a reusable casing which, in order to produce the desired shape of the tool, may be filled with a fluid and be depleted at least in part for removal.
7. Method according to one of the previous claims, wherein the tool (52) is configured at least partly as braid or braid-like structure and the tool (52) is tensioned for removal in order to reduce the cross-section in such a way that a removal is made possible.
8. Method according to one of the previous claims, wherein the tool (52; 54; 56) has at least one mechanically displaceable area, which is displaceable by folding, pivoting, rotating, etc. in order to modify the shape of the tool (52; 54; 56).
9. Method according to one of the previous claims, wherein a vascular prosthesis, a stent-graft, an occluder, a flow diverter, a coil, a cardiac valve frame, an AAA stent, a TAA stent, a gastroenterologic stent or a peripheral stent is produced.

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