METHOD FOR PRODUCING A PROSTHESIS FOR REINFORCING THE ABDOMINAL WALL

Abstract

The invention relates to a method for producing a prosthesis comprising a knitted structure made in one piece, in which method a knit (1) comprising a base sheet (2) and a succession of perpendicular folds (3) is produced in a single knitting step, and said knit (1) is then cut on each side of said folds (3) in order to obtain said knitted structure.

Claims

1-5. (canceled)

6. An implantable prosthesis for reinforcing an abdominal wall comprising a one-piece generally T-shaped knit structure, the knit structure comprising a base portion, which is substantially plane and flexible and at least one fold portion which is flexible and extending substantially perpendicular from a first face of said base portion, wherein the generally T-shape is without a discontinuity between the base portion and the at least one fold portion of the knit structure.

7. The implantable prosthesis of claim 6, wherein the base portion and the fold portion of the generally T-shaped knit structure comprise at least a first and second biocompatible yarn.

8. The implantable prosthesis of claim 7, wherein at least one of the first and second biocompatible yarns comprise a bioabsorbable material selected from the group consisting of polylactic acid (PLA), polyglycolic acid (PGA), oxidized cellulose, polycaprolactone (PCL), polydioxanone (PDO), trimethylene carbonate (TMC), polyvinyl alcohol (PVA), polyhydroxyalkanoates (PHAs), polyamides, polyesters, copolymers thereof, and mixtures thereof.

9. The implantable prosthesis of claim 7, wherein at least one of the first and second biocompatible yarns comprise a non-bioabsorbable material selected from the group consisting of polyethylene terephthalate (PET), polyamides, aramids, expanded polytetrafluoroethylene, polyurethane, polyvinylidene difluoride (PVDF), polybutyl esters, PEEK (polyether ether ketone), polyethylene, polypropylene, and combinations thereof.

10. The implantable prosthesis of claim 7, wherein the base portion further comprises at least a third biocompatible yarn which connects a first part of the base portion to a second part of the base portion across the fold portion.

11. The implantable prosthesis of claim 10, wherein the third biocompatible yarn comprises a bioabsorbable material selected from the group consisting of polylactic acid (PLA), polyglycolic acid (PGA), oxidized cellulose, polycaprolactone (PCL), polydioxanone (PDO), trimethylene carbonate (TMC), polyvinyl alcohol (PVA), polyhydroxyalkanoates (PHAs), polyamides, polyesters, copolymers thereof, and mixtures thereof.

12. The implantable prosthesis of claim 10, wherein the third biocompatible yarn comprises a non-bioabsorbable material selected from the group consisting of polyethylene terephthalate (PET), polyamides, aramids, expanded polytetrafluoroethylene, polyurethane, polyvinylidene difluoride (PVDF), polybutyl esters, PEEK (polyether ether ketone), polyethylene, polypropylene, and combinations thereof.

13. The implantable prosthesis of claim 6, wherein the knit structure comprises a plurality of folds.

14. The implantable prosthesis of claim 13, wherein the plurality of folds are spaced apart at uniform intervals across the knit structure.

15. The implantable prosthesis of claim 6, wherein the knit structure is sufficiently flexible to be folded back upon itself.

16. The implantable prosthesis of claim 10, wherein at least one of the first, second, and third biocompatible yarns is a monofilament.

17. The implantable prosthesis of claim 10, wherein at least one of the first, second, and third biocompatible yarns is a multifilament.

18. The implantable prosthesis of claim 10, wherein the first, second, and third biocompatible yarns are each a monofilament.

19. The implantable prosthesis of claim 18, wherein the monofilament of the third biocompatible yarn has a mean diameter greater than a mean diameter each of the monofilaments of first and second biocompatible yarns.

20. The implantable prosthesis of claim 19, wherein the mean diameter of the monofilament of the third biocompatible yarn is 150 m.

21. The implantable prosthesis of claim 19, wherein the mean diameter of each of the monofilaments of the first and second biocompatible yarns is 80 m.

22. The implantable prosthesis of claim 18, wherein the first, second, and third biocompatible yarns comprise polylactic acid (PLA).

23. The implantable prosthesis of claim 18, wherein the first, second, and third biocompatible yarns comprise polyethylene terephthalate (PET).

22. The implantable prosthesis of claim 6, wherein the knit structure is thermoset.

23. The implantable prosthesis of claim 6, further comprising an anti-adhesion coating on a second face of the base portion opposite the first face of the base portion.

24. The implantable prosthesis of claim 23, wherein the anti-adhesion coating is a bioabsorbable film.

25. The implantable prosthesis of claim 24, wherein the bioabsorbable film comprises collagen.

Description

[0067] The advantages of the present invention will become clearer from the following description and example and from the attached drawings, in which:

[0068] FIGS. 1A and 1B are representations of the charts of the weave repeat of bar B1 for implementing the method according to the invention,

[0069] FIG. 1C is a representation of the chart of the weave repeat for bar B2 for implementing the method according to the invention,

[0070] FIG. 1D is a representation of the chart of the weave repeat of bar B3 for implementing the method according to the invention,

[0071] FIG. 2 is a diagram showing a perspective view of a knit obtained by the method according to the invention,

[0072] FIG. 3 is a diagram showing a perspective view of a knitted structure of a prosthesis according to the invention,

[0073] FIG. 4 is a cross-sectional view of a prosthesis according to the invention in place within an incision in an abdominal wall that is to be closed.

EXAMPLE

[0074] A knit comprising a base sheet and a succession of substantially perpendicular folds is produced by the method according to the invention on a warp knitting machine with three guide bars B1, B2 and B3, such as those described above, where bar B1 is in position 1 on the knitting machine, bar B2 is in position 2, and bar B3 is in position 3. The threading, the run-in rates, the weaves and the charts are the following, in accordance with the standard ISO 11676: [0075] B1: [(0-0/0-0/1-0/1-1/1-1/1-0)15](1-0)/[(0-0)45]/0-1/1-0//

[0076] Bar B1 is threaded 1 full, 3 empty, its dedicated run-in D1 is variable: thus, the value of D1 is positive and constant, in other words ranging from 1,000 to 2,500 mm/rack, a rack corresponding to 480 meshes, on a first part of the weave repeat, namely on the part [(0-0/0-0/1-0/1-1/1-1/1-0)15]. Then this value decreases and tends towards zero on the part of the weave repeat [(0-0)45].

[0077] The yarn threaded on bar B1 is, for example, a monofilament yarn of polylactic acid (PLA) having a mean diameter of 150 m. [0078] B2: [1-0/2-3/2-1/2-3/1-0/1-2//]23

[0079] Bar B2 is threaded 1 full, 1 empty, its dedicated run-in D2 has a positive constant value, in other words ranging from 1,000 to 2,500 mm/rack, a rack corresponding to 480 meshes. [0080] B3: [3-4/2-1/2-3/2-1/3-4/3-2//]23

[0081] Bar B3 is threaded 1 full, 1 empty, its dedicated run-in D3 has a positive constant value, in other words ranging from 1,000 to 2,500 mm/rack, a rack corresponding to 480 meshes.

[0082] The yarns threaded on the bars B2 and B3 are, for example, monofilament yarns of polylactic acid (PLA) having a mean diameter of 80 m.

[0083] Thus, the present example will result in a knit, hence a knitted structure, that is entirely bioabsorbable.

[0084] Alternatively, if the aim is to produce a permanent knit, that is to say a non-bioabsorbable knit, the yarns threaded on the three bars could be monofilaments of polyethylene terephthalate (PET).

[0085] FIG. 1A illustrates the chart, namely the movement over 6 meshes, of the yarn of bar B1 on the first part of its weave, namely on the part [(0-0/0-0/1-0/1-1/1-1/1-0)15] on which the value of D1 is constant and positive. The movement shown in this figure for 6 meshes is repeated 15 times, over a total of 90 meshes.

[0086] FIG. 1B illustrates the movement of the yarn of bar B1 on the second part of its weave, namely on the part [(0-0)45] on which the value of D1 tends towards 0. Indeed, on this first part of the weave, namely for 45 meshes, the yarn remains as it were in place, since it is not used up.

[0087] FIG. 1C illustrates the chart, namely the movement over 6 meshes, of the yarn of bar B2 on the whole of its weave, the value D2 being constant and positive. The movement shown in this figure for 6 meshes is repeated 23 times, on a total of 138 meshes.

[0088] FIG. 1D illustrates the chart, namely the movement over 6 meshes, of the yarn of bar B3 on the whole of its weave, the value D3 being constant and positive. The movement shown in this figure for 6 meshes is repeated 23 times, on a total of 138 meshes.

[0089] As will be clear from the above weave repeats, when the values of the three run-in rates D1, D2 and D3 are positive and constant, the chart comprises 6 meshes (numbered from 1 to 6 in FIGS. 1A, 1C and 1D). In other words, for each bar, the yarn repeats the same chart and recommences the same movement every 6 meshes.

[0090] When they are constant and positive, the values of run-in rates D1-D3 are appropriate to the respective movements of the guide bars. By way of example, these values are generally in excess of 1,000 mm/rack, a rack corresponding to 480 meshes.

[0091] Moreover, the weave repeat comprises 138 meshes. Thus, for bars B2 and B3, the same chart (6 meshes) is repeated 23 times on one weave repeat.

[0092] For bar B1, the same chart (6 meshes) is repeated 15 times, in other words on 90 meshes, with the value D1 of the dedicated speed constant and positive.

[0093] Then, after a transition mesh, the chart (0-0) is repeated 45 times, in other words on 45 meshes, with the value D1 tending towards 0. This part of the weave repeat is illustrated in FIG. 1B.

[0094] Finally, the weave repeat for bar B1 ends with two transition meshes.

[0095] Thus, during a defined period of the weave repeat, in other words during a defined number of meshes, namely on the first 90 meshes of the weave repeat in the present example, the three bars B1, B2 and B3 are supplied with yarns at dedicated run-in rates which all have constant and positive values, and which are preferably all greater than or equal to 1,000 mm/rack, and the three bars produce the substantially plane base sheet of the knit.

[0096] Then, after a transition mesh, the value of the dedicated run-in D1 of bar B1 is reduced so as to tend towards 0 across a defined number of meshes, namely 45 meshes in the present example. During these 45 meshes, the respective dedicated run-in rates of the other two bars B2 and B3 continue to produce their respective parts of the knit of the base sheet. Since the latter cannot be generated in the direction of production of the knit on account of the value of the run-in D1 of bar B1 tending towards 0, it extends perpendicularly with respect to the direction of production of the knit and forms a fold.

[0097] Once the 45 meshes have been produced, and after two transition meshes, the weave repeat is recommenced from the start. Thus, the dedicated run-in D1 resumes its initial positive value greater than or equal to 1,000 mm/rack, and the three bars resume their respective productions of the knit in the direction of production of the knit and they again form the substantially plane base sheet, until the next variation of the value of D1 and the production of the following fold.

[0098] A knit is thereby obtained which comprises a base sheet and a succession of substantially perpendicular folds. In FIG. 2, such a knit 1 is shown that has been obtained according to the method described above. The knit 1 comprises a substantially plane base sheet 2, and perpendicular folds 3 spaced apart from one another at uniform intervals corresponding to the weave repeat. This figure also shows schematically the yarns 4 of bar B1, which have not advanced in the direction of production of the knit 1, indicated by the arrow F, during the decrease in the value of D1 across the 45 meshes of the second part of the weave repeat of bar B1 as described above. As is clear from this figure, the yarns 4 form an integral part of the knit 1, and they join the base sheet 2 to the fold 3 without creating any discontinuity or area of weakness.

[0099] To produce a prosthesis according to the invention from the knit 1 obtained above, the knit 1 is then cut in the area of its base sheet 2, on each side of a perpendicular fold 3, along the cutting lines 5 indicated by dot-and-dash lines, this step being indicated schematically in FIG. 2 by the representation of a pair of scissors.

[0100] A knitted structure 6, as shown in FIG. 3, is thus obtained in one piece. This knitted structure 6 has the general shape of a T, shown upside down in this figure, and thus comprises a first portion 7, which is substantially plane and flexible and can be placed between the abdominal wall and the abdominal cavity, and a second portion 8, which is substantially plane and flexible and is intended to be placed between the two margins of a parietal incision, as will be seen in FIG. 4, said second portion 8 extending substantially perpendicularly from one face of said first portion 7.

[0101] Thus, the knitted structure 6 forming the T-shaped skeleton of the prosthesis according to the invention is made in one piece, and there is no area of weakness created at the join 9 between the first portion 7 and the second portion 8.

[0102] Moreover, the knitted structure of the present example is composed of monofilament yarns. Thus, its stability and the retention of its T shape in the absence of external stress are particularly excellent. Moreover, the three bars B1-B3 above are all threaded with monofilament yarns of one and the same biocompatible material, namely polylactic acid (PLA), the yarns of bar B1 having a mean diameter greater than the mean diameter of the yarns of bars B2 and B3. This results in optimal continuity of the properties of strength of the two portions of the knitted structure in the area of the joining line of said two portions.

[0103] Therefore, when the knitted structure 6 is stressed mechanically in the direction of production of the knit (see FIG. 2), there is no risk of its mechanical performance dropping at the join between the first portion 7 and the second portion 8.

[0104] The knitted structure 6 can be used as it is as a prosthesis for reinforcing the abdominal wall.

[0105] The knitted structure 6 can be subjected to one or more steps that are customary in the manufacture of a prosthesis, for example thermosetting, washing, cutting, thermoforming.

[0106] In one embodiment, and with reference to FIG. 4, the prosthesis 10 according to the invention comprises a knitted structure 6 as described above which is thermoset and which is provided, on the face of the first portion 7 directed away from the second portion 8, with a layer of anti-adhesion coating 11, as shown in FIG. 4.

[0107] FIG. 4 shows an incision 100 in the abdominal wall 101, for example created for the needs of a surgical intervention. The skin 103, the abdominal wall 101 and the peritoneum 104 have been incised. Once the surgical intervention has been completed, at the time of closure of this incision 100, the surgeon introduces the prosthesis 10 into the abdominal cavity 102 and positions it so as to place the first portion 7 between the abdominal wall 101 and the abdominal cavity 102, with the anti-adhesion coating 11 opposite the abdominal cavity 102, and the second portion 8 between the two margins of the incision 100. In the prosthesis 10, the knitted structure 6 and the anti-adhesion coating 11 are sufficiently flexible to be able to be deformed when the prosthesis is introduced at the site of implantation.

[0108] The surgeon can then suture the second portion 8 of the prosthesis 10 to the muscles of the abdominal wall 101.

[0109] The prosthesis 10 thus implanted is able to reinforce the abdominal wall and reduce the risk of occurrence of a hernia after an incision has been made in the abdominal wall for the requirements of a surgical intervention. In particular, since the knitted structure 6 forming the skeleton of the prosthesis 10 is made in one piece, the prosthesis shows no discontinuity in its performance at the join between the first portion 7 and the second portion 8. Therefore, the risks of the prosthesis tearing at this join under the effect of the pressures/forces applied to the prosthesis in the direction of its width are extremely limited.