Two-sides gripping knit

Abstract

The invention relates to a knit having barbs protruding outwards from both faces obtained by knitting yarns of biocompatible material in guide-bars B2, B3 and B4 of a knitting machine, wherein the knitting patterns followed by guide-bars B2 and B3 involve at least two needles and produce an arrangement of yarns defining two faces of the knit, the knitting pattern followed by guide-bar B4 making stitches generating loops protruding outwards from each of the faces of the knit, guide-bar B4 being threaded with a hot-melt monofilament yarn, heat-setting the knit, forming barbs by cutting the loops via melting.

Claims

1. A prosthetic porous knit comprising an arrangement of at least first, second, and third yarns defining at least two faces for the knit, said knit provided with barbs protruding outwards from the at least two faces, said first and second yarns being non-biodegradable yarns defining a body of the knit and the third yarn being a biodegradable yarn defining the barbs, wherein the knit shows a tensile breaking elongation in a warp direction of at least 50%.

2. The prosthetic porous knit according to claim 1, wherein the tensile breaking elongation in the warp direction is at least about 70%.

3. The prosthetic porous knit according to claim 1, wherein the tensile breaking elongation in the warp direction is at least about 100%.

4. The prosthetic porous knit according to claim 1, wherein the tensile breaking elongation in the warp direction is about 108%.

5. The prosthetic porous knit according to claim 1, wherein the first and second yarns comprise monofilaments of polyethylene terephthalate.

6. The prosthetic porous knit according to claim 1, wherein the third yarn comprises monofilaments of a hot-melt biodegradable material.

7. The prosthetic porous knit according to claim 6, wherein the hot-melt biodegradable material includes poly-L-lactic acid.

8. The prosthetic porous knit according to claim 6, wherein each barb has a head with dimensions greater than a diameter of the monofilament, the head configured to grip and fix to biological tissues.

9. The prosthetic porous knit according to claim 6, wherein each barb has a head with dimensions greater than a diameter of the monofilament, the head configured to grip and fix to other porous textiles.

10. The prosthetic porous knit according to claim 1, wherein the first, second and third yarns define the knit having a knit pattern as follows: B2: 5-6/3-4/1-0/4-3// B3: 1-0/3-2/5-6/2-3// B4: 5-4/2-3/0-1/3-2//, respectively.

11. The prosthetic porous knit according to claim 1, wherein the first, second and third yarns define the knit having a knit pattern as follows: B2: 0-1/3-4/7-6/4-3/0-1/2-1// B3: 7-6/4-3/0-1/3-4/7-6/5-6// B4: 4-3/1-2/0-1/2-1/4-3/2-2//, respectively.

12. The prosthetic porous knit according to claim 1, further comprising an anti-adhesion coating thereon.

13. A prosthetic porous knit comprising an arrangement of yarns of biocompatible material defining at least two faces for the knit, said knit being provided with barbs protruding outwards from the at least two faces, wherein the knit shows a tensile elongation under 50 N in a warp direction of at least about 30%.

14. The prosthetic porous knit according to claim 13, wherein the knit shows the tensile elongation under 50 N in the warp direction of at least about 60%.

15. The prosthetic porous knit according to claim 13, wherein the knit shows the tensile elongation under 50 N in the warp direction of at least about 80%.

16. The prosthetic porous knit according to claim 13, wherein the knit shows the tensile elongation under 50 N in the warp direction of about 85%.

17. A two-sided fixation patch for approximating two tissue layers comprising at least one knit provided with barbs protruding outwards from the at least two faces, said knit including an arrangement of at least first, second, and third yarns, said first and second yarns being non-biodegradable yarns defining a body of the knit and the third yarn being a biodegradable yarn defining the barbs, wherein the knit shows at least one of a tensile elongation under 50 N in a warp direction of at least 30% and a tensile breaking elongation in a warp direction of at least 50%.

18. A prothesis for wall reinforcement in parietal or visceral surgery comprising at least one knit provided with barbs protruding outwards from the at least two faces, said knit including an arrangement of at least first, second, and third yarns, said first and second yarns being non-biodegradable yarns defining a body of the knit and the third yarn being a biodegradable yarn defining the barbs, wherein the knit shows at least one of a tensile elongation under 50 N in a warp direction of at least 30% and a tensile breaking elongation in a warp direction of at least 50%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood from the following detailed description and examples, and also from the figures, in which:

(2) FIG. 1A is a schematic view of a knitting pattern suitable for guide-bar B2 of the method and knit of the invention,

(3) FIG. 1B is a schematic view of a knitting pattern suitable for guide-bar B3 of the method and knit of the invention,

(4) FIG. 1C is a schematic view of a knitting pattern suitable for guide-bar B4 of the method and knit of the invention,

(5) FIG. 2 is a schematic view of the knitting patterns of FIGS. 1A-1C shown together, permitting production of a knit according to the invention.

EXAMPLE 1

(6) A prosthetic knit according to the invention is produced on a warp knitting machine with four guide bars B1, B2, B3 and B4, as described above, where the bar B1 is in position 1 on the knitting machine, the bar B2 is in position 2, the bar B3 is in position 3, and the bar B4 is in position 4.

(7) Guide-bar B1 is unthreaded.

(8) Guide-bars B2 and B3 are threaded two full, three empty, according to the following knitting pattern according to the standard ISO 11676 (publication year 2014): B2: 5-6/3-4/1-0/4-3// B3: 1-0/3-2/5-6/2-3//

(9) And Guide-bar B4 is threaded one full, four empty, according to the following knitting pattern according to the standard ISO 11676 (publication year 2014): B4: 5-4/2-3/0-1/3-2//

(10) The yarns threaded in guide-bars B2 and B3 are monofilaments made of polyethylene terephthalate (PET) having a diameter of 0.09 mm.

(11) The yarns threaded in guide-bar B4 are monofilaments of poly-L-lactic acid (PLLA) having a diameter of 0.15 mm.

DETAILED DESCRIPTION OF EMBODIMENTS

(12) The respective knitting patterns for B2, B3 and B4 are illustrated in FIGS. 1A to 1C in a representation well known to a person skilled in the art, where «wa» indicates the warp direction and «we» indicates the weft direction. For each Figure, the graphic shows the movement of the guide-bar. The guide-bars' movement is read from bottom to top, the first knitted course being at the bottom.

(13) As appears on these figures, six needles (numbered from 1 to 6 on the figures) are used for each knitting pattern of B2 and B3. A set of five needles (numbered from 1 to 5 on the figure) is used for the knitting pattern of B4.

(14) In FIG. 2 is illustrated the combination of the three knitting patterns indicated by a fine line for B2, by a dot-and-dash line for B3, and by a solid line for B4, where «wa» indicates the warp direction and «we» indicates the weft direction.

(15) The yarns threaded in B2 and B3 constitute the base of the knit of the present knit, since the hot-melt monofilament yarn, intended to generate the barbs, will be regularly cut during the melting step. The knitting patterns of guide-bars B2 and B3 produce an arrangement of yarns defining the two faces of the knit. They make stitches.

(16) The combination of the knitting patterns, as described in this example, makes it possible to directly produce, by knitting, a porous knit which, on each of its two faces, has loops capable of giving rise to outwardly protruding barbs.

(17) On FIG. 2 are shown two stitches 101 and 102 produced by guide-bar B4. Stitch 101 is for example the stitch produced on a first side of the knit, that will generate a loop on said first side of the knit, and further on barbs, after melting of the loop. Stitch 102 is the stitch produced on the opposite side of the knit that will generate a loop on said opposite side of the knit, and further on barbs, after melting of the loop.

(18) Once the knit has been produced as indicated above, it is heat-set, for example at 110° C., in order to stabilize it in length and width.

(19) After the heat-setting step, each face of the knit is placed in contact with a cylinder containing an electrical heating resistor so as to melt the loops present on said face.

(20) In the present example, the melting point of poly-L-lactic acid being 165° C., the cylinder is heated at a temperature T of 250° C.

(21) On melting, each loop produced by monofilaments of guide-bar B4 cuts in two and gives rise to two barbs protruding outwards from the face of the knit, each barb preferably having a head with dimensions greater than those of the diameter of the monofilament yarn forming the initial loop.

(22) The following properties of the knit of the invention of the present example have been determined as follows:

(23) Linear density (g/m.sup.2): measured according to ISO 3801: 1977 «Determination of mass per unit length and mass per unit area», 5 samples, 1 dm.sup.2 disk,

(24) pore size (width×height) (mm): knit biggest pores width and height are measured making one measurement on 5 individual samples of dimensions 100×50 mm, with a profile projector such as a projector,

(25) Thickness: is measured according to ISO 9073-2: 1997 “Textiles—test methods for nonwovens—Part 2: Determination of thickness”, method used for voluminous nonwovens with a thickness less than 20 mm, 10 samples, 100×50 mm,

(26) Tensile strength (N), tensile elongation (%) and elongation under 50 N (%): are measured according to ISO 13934-1: 1999 “Determination of breaking strength and elongation”, 5 samples, width: 50 mm, length: 200 mm between the jaws, Crosshead speed: 100 mm/min, Pre-load: 0.5 N, using a traction testing machine such as the Hounsfield model H5KS (Hounsfield, Redhill, England),

(27) Bursting strength (kPa): measured according to ISO 13938-2: 1999 “Textiles—Bursting properties of fabrics—Pneumatic method for determination of bursting strength and bursting deformation”, 5 samples using a Bursting strength tester, heal model Truburst,

(28) Suture pull out strength in the warp direction and in the weft direction measured as follows: a USP 2 suture yarn is passed through a pore of a 50×100 mm sample, at 10 mm from the edge of a small side of the sample, and is tracted away using a traction testing machine such as the Hounsfield model H5KS (Hounsfield, Redhill, England) with the following conditions: 5 samples, width 50 mm, 100 mm between the jaws, crosshead speed: 100 mm/min,

(29) Tear strength (N) in the warp direction and in the weft direction: measured according to superseded ISO 4674:1977 “Determination of tear resistance of coated fabrics” Method A2, 5 samples, width: 75 mm, Tear length≤145 mm, crosshead speed: 100 mm/min.

(30) The results are collected in the following table:

(31) TABLE-US-00001 TABLE I properties of the knit Property Knit of present example Surface density (g/m.sup.2) 87 Thickness (mm) 4.1 Pore size (mm.sup.2) (width × height) 1.7 × 1.6 Bursting strength (kPa) 132 ± 8 Warp Weft Tensile breaking strength (N) 112 ± 8 239 ± 6  Tensile breaking elongation (%) 108 ± 6 49 ± 1 Tensile Elongation under 50N (%)  85 ± 2 19 ± 1 Tear strength (N)  29 ± 2 27 ± 3 Suture pull-out strength (N)  41 ± 4 35 ± 4

(32) The knit of the invention of the present example therefore shows a tensile breaking elongation of 108% in the warp direction and a tensile breaking elongation of 49% in the weft direction. This knit further shows a tensile elongation under 50 N of 85% in the warp direction and a tensile elongation under 50 N of 19% in the weft direction.

(33) The knit of the present example is therefore particularly adapted for approximating two tissue layers that have been previously separated, by gripping one tissue layer via the barbs of one of its faces, and gripping the other tissue layer via the barbs of its other face. Thanks to the elongation properties of the knit, the approximated tissue layers are free to move with respect to each other, while being firmly attached to each other, thereby being capable of smoothly adapting to pressures of various directions and intensities generated by the movements of a patient in its daily life.

(34) Such a knit can be used as it is, directly as a two-sides fixation patch for approximating two tissue layers which have been previously separated or as a prosthesis in parietal or visceral surgery for wall reinforcement. Alternatively, this knit can be combined with another textile, with two textiles (one on each face), or with an anti-adhesion film on one or both of its faces. The barbs can be covered with an anti-adhesion coating to prevent them from becoming entangled in the body of the knit when the latter is folded up on itself, for example in order to be introduced into a trocar.

(35) The knit of the present example further allows preventing the appearance of seroma subsequent to surgery.

EXAMPLE 2 (COMPARATIVE)

(36) A comparative knit, having barbs protruding outwards from both faces, has been manufactured according to the following method: the comparative knit is produced on a warp knitting machine with four guide bars B1, B2, B3 and B4, where the bar B1 is in position 1 on the knitting machine, the bar B2 is in position 2, the bar B3 is in position 3, and the bar B4 is in position 4.

(37) Guide-bar B1 is threaded one full, three empty according to the following knitting pattern according to the standard ISO 11676 (publication year 2014): B1: 2-3/2-1/1-0/1-2//

(38) Guide-bar B2 is threaded one full, one empty according to the following knitting pattern according to the standard ISO 11676 (publication year 2014): B2: 1-0/0-1//

(39) The knitting pattern of guide-bar B2 therefore involves only one needle.

(40) Guide-bar B3 is threaded one full, one empty according to the following knitting pattern according to the standard ISO 11676 (publication year 2014): B3: 1-0/5-5/1-0/3-3//

(41) Guide-bar B4 is threaded one full, three empty according to the following knitting pattern according to the standard ISO 11676 (publication year 2014): B4: 2-1/5-5/3-4/0-0//

(42) The yarns threaded in guide-bars B2 and B3 are monofilaments made of polyethylene terephthalate (PET) having a diameter of 0.09 mm.

(43) The yarns threaded in guide-bars B1 and B4 and intended to generate the barbs are monofilaments of poly-L-lactic acid (PLLA) having a diameter of 0.15 mm.

(44) The tensile breaking elongation and the tensile elongations under 50 N in the warp direction and in the weft direction have been measured for the comparative knit according to the methods described at Example 1.

(45) The results are collected in the following table:

(46) TABLE-US-00002 TABLE II comparison of elongation parameters between a knit of the invention and a comparative knit Comparative knit of Example 2 Knit of Example 1 Property Warp Weft Warp Weft Tensile breaking 45 ± 4 108 ± 8 108 ± 6 49 ± 1 elongation (%) Tensile 12 ± 2  45 ± 2  85 ± 2 19 ± 1 Elongations under 50N (%)

(47) As appears from these results, the knit of the invention shows a tensile breaking elongation in the warp direction more than two times higher than that of the comparative knit. The knit of the invention further shows tensile elongation under 50 N in the warp direction more than six times higher than that of the comparative knit.

(48) The knit of the invention is therefore particularly adapted to conform to the variations of intensity and of direction of pressures in the anatomy of a person subsequent to the movements of this person during his daily life.