WO2006066882A2

WO2006066882A2 - Flat implant and method for the production thereof

Info

Publication number: WO2006066882A2
Application number: PCT/EP2005/013719
Authority: WO
Inventors: Erich K Odermatt; Wolfgang Abele
Original assignee: Aesculap Ag & Co. Kg
Priority date: 2004-12-20
Filing date: 2005-12-20
Publication date: 2006-06-29
Also published as: EP1830901A2; WO2006066882A3; DE102004062798A1

Abstract

The invention relates to a flat implant which is in the form of a flat porous textile material and which consists of, at least on one side, a sealed surface which is air-tight and which comprises a non-reabsorbing impermeable layer. The flexibility of the layer is in the order of magnitude of the flexibility of the flat porous material. The implant is particularly suitable for treating postoperative hernias.

Description

description

Flat implant and method for its production

The present invention relates to a planar implant, in particular a hernia mesh, and a method for its production.

The hernia or the abortion is a common disease that needs to be treated surgically. This is generally a passage of organs or parts of organs from the natural body cavity through a preformed or acquired gap. Hernias occur mainly as a result of muscle or connective tissue weaknesses associated with overuse, age-related relaxation, congenital weakening of the abdominal wall, or insufficient scarring following a cut (scarring).

Surgical treatment usually involves surgical intervention in which the contents of the fracture are transferred back from the hernia sac to the abdomen and the hernia is closed. This closure of the hernia is conventionally done by a suture.

After a hernia operation, it is not uncommon for a new break, a so-called fracture recurrence. Therefore, in modern treatment methods increasingly artificial reinforcement materials for abdominal wall reconstruction, such as polypropylene or polyester mesh used.

Although the use of such nets has led to a significant reduction in the rate of recurrence, these implants are not unproblematic because of possible infections or fistulae, but especially because of the risk of soft tissue adhesions. The previous implants represent open textile structures that promote adhesion of cells and infiltration with cells. This is on the one hand advantageous because a firm connection between the implant and the abdominal wall made and thus the desired support function is ensured. On the other hand, hard-to-loosen adhesions in the abdomen with hardening (scarring), impairments of the intestine and the internal organs and related discomfort in the patient can be the result.

A planar implant provided by the applicant avoids the problem of unwanted soft tissue adhesions in that the implant has on one side a microporous structuring which, while permitting the exchange of substances, in particular nutrients, prevents adhesion and growth of body cells. In this connection reference is made to DE 19912648. In a development, the microporous structuring can still be sealed with a resorbable anti-adhesive agent, in particular with polyvinyl alcohol (PVA), as is known, for example, from the publication US 2003/0040809.

It has as its object to provide an implant for use in surgical procedures, in particular in hernia operations, which avoids the difficulties of implants of the prior art and also simple and inexpensive to manufacture and can be used by conventional surgical methods.

This object is achieved by a planar implant, in particular a hernia mesh, in the form of a flat, porous textile material which is tightly sealed on at least one side with a nonabsorbable impermeable layer which is elastic and whose flexibility is of the order of the flexibility of the flat porous material is. The term sealing is understood to mean the closing of the implant surface. This leads to a reduction in the structuring of the implant surface. Elevations or depressions resulting, for example, from the production technique of the sheet-like porous material are compensated by the sealed or closed surface. In particular, parts protruding from the sheet-like porous material are enclosed.

In this way, the sealed surface, with its lack of porosity and surface structure, is unsuitable for cell adhesion since the cells do not find anchoring opportunities on the closed surface required for their growth. In this way, colonization of the sealed implant surface with cells is completely prevented. Unwanted adhesions are avoided. In addition, the sealing material renders the edges of the sheet-like porous material more forgiving.

In a preferred embodiment of the invention, the thickness of the sealing layer is 0.02 to 0.9 mm, in particular 0.4 to 0.5 mm. The sealing layer preferably has a layer thickness of <200 μm, in particular from 0.03 to 0.10 mm.

The material of the sealing layer is advantageously a biocompatible material, for example silicone, polypropylene, polyester, polytetrafluoroethylene and / or polyurethane. Polyurethane is particularly preferred because of its soft elastic properties. Preferably, the material of the sealing layer is soluble in an organic solvent.

In a preferred embodiment of the invention, the sealing layer is essentially made of polyurethane, preferably linoleum. - A -

rem, aliphatic polyurethane formed. The sealing layer is particularly preferably formed of polyurethane, preferably of linear, aliphatic polyurethane. According to the invention, it may be provided that the polyurethane is present preferably with a total surface weight of 50 to 180 μm ² and preferably a thickness of 0.4 to 0.5 mm. Preferably, the polyurethane has a molecular weight> 15,000 daltons, especially> 20,000 daltons, and a melting range of 165 ^° C. Polyurethane is particularly preferred over the reinforcing materials commonly used in hernia repair, especially polypropylene or polyester meshes, because of its elastomeric and extensible properties In addition, polyurethane, in particular linear polyurethane, is advantageously distinguished by its high biocompatibility and stability, In particular, the polyurethane of the implant according to the invention has a long-term stability of> 5 years In this way, a permanent and carefree whereabouts of the invention ensured implant in the body of the patient.

In a further preferred embodiment of the invention, the sealing layer is formed essentially of polyurethaneurea, preferably of linear polyurethaneurea. The sealing layer is particularly preferably formed from polyurethaneurea, preferably from linear polyurethaneurea.

In a further embodiment, the sealing layer of the implant according to the invention is free of plasticizers. This is particularly advantageous because in this way an unnecessary burden on the patient with additives is avoided. According to the invention, the sealing layer has a smooth, closed surface. Smooth in this case means that the surface has no structuring, for example by a textile construction. In this way, a sticking and ingrowth or anchoring of cells prevented. Furthermore, smooth means that no fibers of the sheet-like porous material protrude from the surface. The closed surface is in particular not microporous, so that a mass transfer is also not possible.

Furthermore, it can be provided according to the invention that the sealing layer is present as cast film, that is to say the modification of the surface of the implant according to the invention is based on the application of a cast film. The thickness of the cast film is preferably 0.02 to 0.9 mm, in particular 0.03 to 0.10 mm. In a particular embodiment, the cast film preferably contains suspended yarns, in particular polypropylene yarns, in particular in an amount of 5 to 45%, the cast film preferably having a thickness of 0.03 to 0.5 mm.

Preferably, the sheet-like porous material, in particular fibers or threads of the flat porous material, of the implant according to the invention is at least partially encased by the sealing layer. In a particularly preferred embodiment, the flat porous material, in particular fibers or threads of the flat porous material, of the implant according to the invention is completely encased by the sealing layer. The flat porous material of the implant according to the invention is preferably completely coated by a layer of polyurethane, in particular linear aliphatic polyurethane.

In a further preferred embodiment, parts, in particular threads of the flat porous material, are at least partially embedded in the material of the sealing layer. This is particularly advantageous because in this way a stable fixation between the sheet-like porous material and the sealing layer is ensured. He- According to the invention, provision may be made for the parts, in particular threads, of the material to penetrate only insignificantly into the sealing layer, so that the spatial extent of the flat porous material is predominantly available for ingrowth of cells out of the abdominal wall. In certain cases, it may also be preferable for the sealing layer to be removable from the flat porous material. Advantageously, the implant is asymmetrical in that the sealing layer does not lie in the median plane of the flexible porous material but is offset towards one surface side.

In a further embodiment of the invention, the sealing layer can be provided with active substances, for example antimicrobial, preferably antibiotic, substances, in order to effectively prevent possible inflammations at the site of implant placement. It may also be preferred to provide the implant with growth factors. Depending on the respective requirements, one or more active substances can be used.

The flat porous textile material can be configured as a woven, woven or knitted fabric, preferably in the form of a net. The textile design of the sheet-like porous material as knitted fabric is particularly preferred because of the elasticity of a knitted fabric. According to the invention, the material may be polypropylene which is preferably in the form of a monofilament knit having a thickness of the monofilament of preferably between 0.1 and 0.15 μm.

In another embodiment of the implant according to the invention, the flat porous material is in the form of a nonwoven, in particular a polypropylene nonwoven. Furthermore, it may be preferred that the sheet-like porous material preferably contains randomized yarns, in particular polypropylene yarns. Furthermore, the sheet-like porous material may have an opening width of 0.1 to 5 mm, in particular 0.2 to 5 mm, in particular of 0.2 to 1 mm or of 2 to 4 mm, and preferably a honeycomb shape. The basis weight of the net-like material is 25 to 80 gm ^'2 . After application of polyurethane as the sealing material, the total basis weight is from 50 to 180 gm ^"2.

According to the invention it can be provided that the implant has a total thickness of 0.1 to 1, 0 mm, in particular from 0.3 to 0.8 mm, in particular from 0.3 to 0.5 mm, wherein the thickness of the sealed Surface is 0.05 to 0.1 mm. The textile carrier has a preferably knitted plain weave with a thickness of 0.25 to 0.7 mm and an at least one-sided open structure with a thickness of 0.01 to 0.15 mm.

In a particularly preferred embodiment of the invention, only one side of the sheet-like porous material is tightly covered by the sealing layer, ie the sealing material, preferably linear polyurethane, does not fully enclose the sheet-like porous material. In a particularly preferred embodiment of the invention, only one side of the sheet-like porous material is tightly covered by the sealing layer and the other side of the implant according to the invention open, wherein the sheet-like porous material is completely encased by the sealing layer. The other side of the implant according to the invention is open, ie the porous structure of the sheet material is exposed to the outside. In this way, an adhesive effect of the implant according to the invention is maintained and enables ingrowth of cells. Preferably, the side of the implant according to the invention facing the abdominal interior is sealed in order to avoid unwanted coalescence with organs and body parts. The side of the implant according to the invention which faces the abdominal wall advantageously has a graspable point on it. pointing, in particular porous, structure to allow adhesion and growth of body cells.

The flat porous material of the implant according to the invention preferably has, on the open side, an open texturing structure known from vascular implants, which is formed, in particular, by textured yarns, floats or velor loops.

Preferably, fibers or threads of the sheet-like porous material, in particular of the knitted fabric, are freely accessible behind the open side. This is particularly advantageous for the ingrowth of cells on this side and thus for anchoring to the abdominal wall.

According to the invention, the sheet-like porous material is elastically extensible in at least one direction, the sealing layer having a higher extensibility than the sheet-like porous material. Advantageously, the sealing layer of the implant according to the invention is transparent, which represents a relief and increased safety for the surgeon.

In a further preferred embodiment of the invention, the surface of the sealing layer is hydrophilized, preferably by coating with phospholipids. According to the invention, it is particularly preferred that the surface of the sealing layer is coated with phosphatidylcholine. Advantageously, the proportion of the phospholipid coating, in particular the phosphatidylcholine coating, 1 to 30 wt .-%, in particular 3 to 10 wt .-%, based on the total weight of the implant. The phospholipid coating of the sealing layer of the planar implant acts in addition to the sealing layer itself antiadhesive. Preferably, the implant according to the invention has a sandwich structure, which is preferably formed from the sheet-like porous material, the sealing layer and the phospholipid coating.

Preferably, the implant according to the invention, in particular for its use in surgery, can be suitably sterilized. Suitable sterilization methods are the customary physical or chemical methods for inactivating microorganisms. The sterilization processes are preferably steam sterilization, for example ethylene oxide gasification, or plasma sterilization (pulsed H2O2). Furthermore, a treatment with ionizing radiation, for example with β-rays or γ-rays, in the range of 0.1 Mrad to 10 Mrad, in particular 0.8 Mrad to 2.5 Mrad, conceivable.

In addition, the implant material according to the invention can be present in a desired cut-size and shape and packaged in this ready-to-use dimension in a suitable manner, in particular in sterile packaging.

In another embodiment, the invention relates to a method for producing a planar implant according to any one of the preceding claims, wherein a solution of the sealing material in a thin layer placed on a smooth surface and the flat porous material is placed on the layer of the solution or the sheet-like porous material placed on a smooth surface and applied a solution of the sealing material on the sheet-like porous material, preferably poured, is. The layer thickness of the solution presented is preferably such that the flat porous material is wetted substantially at least on its underside by the solution, and that the solvent is subsequently evaporated. In a particularly preferred embodiment, the areal po- Roughened material completely wetted by the solution of the sealing material. The flat porous material is preferably in the form of a net, in particular a polypropylene net. In another preferred embodiment, the sheet-like porous material is present as a nonwoven, in particular as a polypropylene nonwoven. As a template for the solution of the sealing material each container can serve with a smooth surface. Preferably, the container is a shell. The solution of the sealing material is preferably a solution of polyurethane, preferably of linear, aliphatic polyurethane, in a low-boiling organic solvent. Preferred solvents are perchlorinated and / or partially chlorinated solvents, for example chloroform or methylene chloride. By evaporation of the solvent, the coating film forms. During solvent evaporation, there is no effect on the surface of the sealant layer. In particular, there is no formation of a microporosity that could allow a mass transfer between the physiological milieu of the body and the implant used according to the invention.

In a further embodiment of the method according to the invention, a solution of the sealing material is used which is provided with active substances, in particular anti-inflammatory and / or wound-promoting substances. Preference is given to using antimicrobial, in particular antibiotic, substances. According to the invention, it can also be provided that the active ingredients are applied to the implant after the production of the planar implant.

In order to avoid solvent vapors, it may be preferable to compress flat porous material, preferably a polypropylene net, into the softened sealing material, which is preferably present as a polyurethane film. But it can be equally beneficial be laminating or lolling the sealing material, preferably in the form of a film on the sheet-like porous material.

In a further embodiment of the method according to the invention, the surface of the sealing layer is hydrophilized antiadhesive, preferably by coating with phospholipids. In a particularly preferred embodiment of the method according to the invention, the surface of the sealing layer is coated with phosphatidylcholine. Advantageously, the phospholipid coating, in particular phosphatidylcholine coating, is made by spraying the surface of the sealing layer. The phospholipids, especially phosphatidylcholine, can be dissolved in chloroform or a hexane / isopropanol / water mixture. In the case of polyurethane as a material for the sealing layer of the planar implant and chloroform as a solvent for the phospholipids, in particular phosphatidylcholine, the spray application is preferably carried out so that the polyurethane is slightly dissolved on its surface in order to bond with the applied phospholipids, in particular phosphatidylcholine to effect.

In a further embodiment of the method according to the invention, the planar implant for coating the sealing layer can be immersed in a phospholipid solution, in particular phosphatidylcholine solution. In the case of polyurethane as a material for the sealing layer and chloroform as a solvent, the planar implant is only briefly, ie for 20 to 40 s, especially for about 30 s, immersed in a phospholipid solution, in particular phosphatidylcholine solution. In this way, the dissolution of polyurethane in chloroform can be substantially avoided. According to the invention, it may be desirable in some cases to use a hexane / isopropanol / water mixture as solvent for the phospholipid coating, in particular phosphatidylcholine coating, since polyurethane is substantially insoluble in such a solvent mixture.

Due to the different functional design of its surfaces, the implant according to the invention is outstandingly suitable as an incisional hernia mesh for the surgical treatment of a fracture recurrence, in particular in the case of large-area fascial gaps. By introducing the implant according to the invention into the abdominal cavity in such a way that the sealed surface is directed to the inside of the abdomen, as already mentioned, undesired adhesive interactions with the intestines, in particular the intestine, are avoided. The opposite open porous side of the planar implant facing the abdominal wall side and allows colonization with body cells on the surface of the implant and thus a composite of abdominal wall and implant. This contributes significantly to a stabilization of the abdominal wall and thus guarantees long-term treatment success.

Further features of the invention will become apparent from the following description of a preferred example in conjunction with the subclaims and the drawings. In this case, the individual features can be implemented individually or in each case in one embodiment of the invention. The example, however, is only illustrative and is not to be construed as limiting.

FIG. 1 shows a plan view from above of the implant 1 according to the invention. FIG. II shows a cross section of the implant 1 according to the invention along the section line II-II in FIG.

example 1 A sheet-like porous material 2 is formed as a net-like knit of monofilament polypropylene, the knitted binding webs 3 forming honeycomb-shaped recesses 4. The knit is porous and flexible. It has on the upper side knitted an open three-dimensionally structured surface 5, which has substantially uniformly distributed Hintergreifmöglichkeiten for ingrowth of body cells and a contiguous cell composite.

The lower side of the fabric has a layer 6 of linear polyurethane laminated to the fabric and sealing the porous sheet 2 of polypropylene at that surface. The thickness of the polyurethane layer 6 is on the order of about 1/10 to 1/20 of the total thickness of the sheet-like porous material 2. The total thickness of the implant 1 according to the invention is about 0.2 mm. The polyurethane layer 6 penetrates only insignificantly into the textile surface of the polypropylene net (FIG. II), so that the volume of the net is mainly available for ingrowth of cells out of the abdominal wall, while the surface 7 of the implant 1 according to the invention sealed by the polyurethane layer 6 prevents such ingrowth of cells on the side of the abdomen. The flexibility of the polyurethane layer 6 is of the order of magnitude of the sheet-like porous material 2 made of polypropylene. The edges of the sheet-like porous material 2 are ausfransfest by itself because of the knit. The polyurethane layer 6 prevents curling of the fabric and additionally reduces the tendency to fringe. If desired or required, the edges can additionally be made ausfransfest by welding the polypropylene fibers 8. For use in surgery, pieces of about 8 x 2 cm to 30 x 30 cm are made. Depending on requirements, these pieces can be cut to size before implantation. Example 2

Polypropylene yarns with a length of 2 to 3 mm are stirred into 100 ml of a 3% strength polyurethane solution to a suspension, so that the proportion of polypropylene yarn is 10% of the solution of polyurethane. The mixture is poured onto a polyurethane film. Gravity causes the yarns to lower to the bottom of the polyurethane film. The polypropylene yarns thereby cause a reinforcement or Ausreisskraftverstärkung of the film.

Example 3

Polypropylene yarns with a length of 15 to 30 mm are mixed in 100 ml of a 3% strength polyurethane solution to a suspension, so that the proportion of polypropylene yarn is 10% of the solution of polyurethane. The mixture is poured onto a polyurethane film. Gravity causes the yarns to lower to the bottom of the polyurethane film. The polypropylene yarns thereby cause a reinforcement or Ausreisskraftverstärkung of the film.

Example 4a

About 200 ml of a polyurethane solution with a concentration of 15 g / l polyurethane in chloroform are placed on a smooth surface. Subsequently, a porous polypropylene net (Optilene Mesh Elastic® or Optilene Mesh LP®, size 30 × 30 cm) is placed on the initially introduced polyurethane solution, wherein the sheet-like porous material is completely wetted by the polyurethane solution. After evaporation of the solvent, a polypropylene net is obtained which is completely encased in polyurethane, the backing side of the polypropylene net being sealed by a smooth closed and dense polyurethane film. In the absence of cross flows, for example by draft, a transparent film is obtained. Example 4b

A porous polypropylene net (Optilene Mesh Elastic® or Optilene Mesh LP®, size 30 × 30 cm) is placed on a smooth base and then with about 200 ml of a polyurethane solution with a concentration of 15 g / l polyurethane in Chloroform poured over. After evaporation of the solvent, a polypropylene net is obtained which is completely encased in polyurethane, the backing side of the polypropylene net being sealed by a smooth closed and dense polyurethane film. In the absence of cross flows, for example by draft, a transparent film is obtained.

Example 5

A polyurethane-coated polypropylene net according to Example 4 is sprayed with a phosphatidylcholine solution having a concentration of 5% by weight of phosphatidylcholine, based on the total weight of the solution (solvent chloroform or hexane / isopropanol / water). After drying the polypropylene network, the spray application is optionally repeated several times. In this way, a planar implant is obtained, the polyurethane layer is coated with phosphatidylcholine, wherein the proportion of phosphatidylcholine coating is about 5% by weight, based on the total weight of the implant.

Example 6

A polyurethane-coated polypropylene net according to Example 4 is held on two tweezers and dipped in a phosphatidylcholine solution for about 30 seconds, the concentration of the solution being about 10% by weight, based on the total weight of the solution (solvent: Chloroform or hexane / isopropanol / water). The implant obtained in this way has on the polyurethane coating on a phosphatidylcholine coating, the proportion of about 5 wt .-%, based on the total weight of the implant, is.

Claims

claims

1. Flat implant, in particular hernia mesh, in the form of a sheet-like porous textile material which is tightly sealed on at least one side with a non-absorbable impermeable layer which is elastic and whose flexibility is of the order of the flexibility of the sheet-like porous material.

2. Areal implant according to claim 1, characterized in that the sealing layer is formed essentially of preferably linear polyurethane.

3. A planar implant according to claim 1 or 2, characterized in that the polyurethane has a molecular weight> 15,000 daltons.

4. Areal implant according to one of the preceding claims, characterized in that the sealing layer is free of plasticizers.

5. A planar implant according to one of the preceding claims, characterized in that the sealing layer has a smooth, in particular a smooth closed, surface.

6. Areal implant according to one of the preceding claims, characterized in that the sealing layer is a cast film.

7. A planar implant according to claim 6, characterized in that the cast film preferably has suspended yarns, in particular polypropylene yarns, in particular in an amount of 5 to 45%.

8. A planar implant according to one of the preceding claims, characterized in that the flat porous material is at least partially, preferably completely, encased by the sealing layer.

9. A planar implant according to one of the preceding claims, characterized in that parts, in particular threads of the flat porous material, are at least partially embedded in the material of the sealing layer.

10. A planar implant according to one of the preceding claims, characterized in that the sheet-like porous material is a preferably monofilament knit, in particular a net, preferably a polypropylene net.

11. Areal implant according to one of claims 1 to 9, characterized in that the flat porous material is a nonwoven, in particular a polypropylene nonwoven.

12. A planar implant according to one of the preceding claims, characterized in that the sheet-like porous material preferably contains randomized yarns, in particular polypropylene yarns.

13. A planar implant according to one of the preceding claims, characterized in that the flat porous material has an opening width of 0.1 to 5 mm, in particular 2 to 4 mm.

14. A planar implant according to one of the preceding claims, characterized in that the sealing layer covers only one side of the sheet-like porous material and the porous structure is exposed on the other side.

15. Flat implant according to one of the preceding claims, characterized in that threads of the sheet-like porous material, in particular of the knitted fabric, are accessible behind the back of the open side.

16. A planar implant according to one of the preceding claims, characterized in that the sheet-like porous material on the open side has an open textile structure known in the case of vascular implants, which is formed, in particular, by textured yarns, floats and / or velor loops.

17. A planar implant according to one of the preceding claims, characterized in that the sheet-like porous material is elastically extensible in at least one direction and the sealing layer has a higher extensibility than the sheet-like porous material.

18. A planar implant according to one of the preceding claims, characterized in that the sealing layer is transparent.

19. A planar implant according to one of the preceding claims, characterized in that the surface of the sealing layer is hydrophilized, preferably by coating with phospholipids.

20. Areal implant according to one of the preceding claims, characterized in that the surface of the sealing layer is coated with phosphatidylcholine.

21. A method for producing the planar implant according to one of the preceding claims, characterized in that a solution of the sealing material presented in a thin layer on a smooth surface and the flat porous material is placed on the layer of the solution or the flat porous material on a smooth Substrate submitted and the solution of the sealing material is applied to the sheet-like porous material, wherein the layer thickness of the solution is preferably such that the sheet-like porous material is wetted substantially at least on its underside by the solution, and then evaporating the solvent.

22. The method according to claim 21, characterized in that the flat porous material is completely wetted.