Barbed prosthetic knit and hernia repair mesh made therefrom as well as process for making said prosthetic knit

Abstract

The present invention relates to a prosthetic knit based on at least a first yarn of biocompatible polymer material defining first and second opposite and openwork faces, and on at least a second biocompatible and heat-fusible monofilament yarn, forming barbs that protrude outwards from at least said first face and are obtained by melting loops generated by said second yarn, the chart followed for the knitting of said first and second yarns on a warp knitting machine having three guide bars B1, B2, B3 being the following, according to the ISO 11676 standard: —Bar B1: 1.0/0.1//—Bar B2: 1.0/7.7/6.6/7.7//—Bar B3: 2.1/5.5/3.4/0.0// said second yarn following the chart of bar B3. The present invention also relates to a process for manufacturing such a knit.

Claims

1. A prosthetic knit comprising at least a first monofilament yarn of biocompatible polymer material defining first and second opposite faces, said first face including barbs protruding substantially perpendicular to a plane of the first face and said second face including openings, wherein the openings and the barbs are distributed such that when the knit is rolled upon itself at least some of the barbs present on the first face are caused to be trapped within some of the openings on the second face, and when the knit is unrolled the trapped barbs will be released from the openings of the second face by applying a maximum force of 3.54±0.85 N.

2. The prosthetic knit according to claim 1, wherein the barbs include a shaft and a head wherein a diameter of the head is greater than a diameter of the shaft.

3. The prosthetic knit according to claim 2, wherein the barbs are made of a bioresorbable material.

4. The prosthetic knit according to claim 3, wherein the first monofilament yarn is made of polyester terephthalate (PET) having a diameter of 0.09 mm.

5. The prosthetic knit according to claim 1, wherein the openings and the barbs are distributed such that the knit experiences a number of points of resistance of 52±11 when the knit is unrolled at a constant extension rate.

6. The prosthetic knit according to claim 1, further comprising a second textile.

7. The prosthetic knit according to claim 1, wherein the barbs are not damaged after unrolling.

8. The prosthetic knit according to claim 1, further comprising a non-stick coating made of a biocompatible material.

9. The prosthetic knit according to claim 1, wherein the first face includes openings.

10. A method for hernia repair comprising rolling a prosthetic knit up on itself, the knit including at least a first monofilament yarn of biocompatible polymer material defining first and second opposite faces, said first face including barbs protruding substantially perpendicular to a plane of the first face and said second face including openings, wherein the openings and the barbs are distributed such that at least some of the barbs present on the first face are caused to be trapped within some of the openings on the second face during rolling of the prosthetic knit, conveying the rolled knit to a site of implantation, and unrolling the knit and releasing the trapped barbs from the openings by exerting a maximum force of 3.54±0.85 N.

11. The method according to claim 10, further comprising introducing the rolled knit into a trocar prior to conveying the rolled knit to the site of implantation.

12. The method according to claim 10, wherein the barbs include a shaft and a head wherein a diameter of the head is greater than a diameter of the shaft.

13. The method according to claim 12, wherein the barbs are made of a bioresorbable material.

14. The method according to claim 13, wherein the barbs are not damaged after unrolling.

15. The method according to claim 10, wherein the first monofilament yarn is made of polyester terephthalate (PET) having a diameter of 0.09 mm.

16. The method according to claim 10, wherein the openings and the barbs are distributed such that the knit experiences a number of points of resistance of 52±11 when the knit is unrolled at a constant extension rate.

17. The method according to claim 10, wherein the prosthetic knit further includes a second textile.

18. A prosthetic knit comprising at least a first monofilament yarn of biocompatible polymer material defining first and second opposite faces, said first face including bioresorbable barbs protruding substantially perpendicular to a plane of the first face, said bioresorbable barbs including a shaft and a head wherein a diameter of the head is greater than a diameter of the shaft, and said second face including openings, wherein the openings and the bioresorbable barbs are distributed such that when the knit is rolled upon itself at least some of the resorbable barbs present on the first face are caused to be trapped within some of the openings on the second face, and when the knit is unrolled the trapped resorbable barbs will be released from the openings of the second face by applying an average force of 1.13±0.33 N.

Description

(1) The advantages of the present invention are illustrated by means of the experimental section which follows and the following supporting figures:

(2) FIGS. 1A to 1C: are diagrams showing the charts followed for the knitting of the yarns of the knits according to the invention,

(3) FIG. 2: is a diagram showing a chart followed for the knitting of the yarns of a knit from the prior art,

(4) FIG. 3: is a diagram illustrating the method for rolling up a knit,

(5) FIGS. 4A and 4B: are diagrams illustrating the test for evaluating the force for unrolling a rolled-up knit,

(6) FIG. 5: shows the curve representing the force applied, in N, as a function of the extension, in mm, of a knit during the unrolling thereof.

EXAMPLE 1

(7) Produced on a warp knitting machine having three guide bars B1, B2 and B3, were a knit A, according to the invention, and a comparative knit B, the chart of which differs from that of the knit according to the invention.

(8) Knit A: according to the invention, having the following chart according to the ISO 11676 standard: Bar B1: 1.0/0.1// Bar B2: 1.0/7.7/6.6/7.7// Bar B3: 2.1/5.5/3.4/0.0//

(9) These charts are illustrated in FIGS. 1A to 1C according to a representation known to a person skilled in the art: the chart of bar B1 is illustrated in FIG. 1A; the chart of bar B2 is illustrated in FIG. 1B and the chart of bar B3 is illustrated in FIG. 1C.

(10) Bar B1 and bar B2 are each threaded 1 full, 1 empty, with a monofilament yarn made of polyester terephthalate (PET) having a diameter of 0.09 mm; bar B3, which gives rise to the barbs, is threaded 1 full, 3 empty, with a heat-fusible monofilament yarn made of polylactic acid having a diameter of 0.15 mm.

(11) Knit B: comparative, having the following chart according to the ISO 11676 standard: Bar B1: 1.0/0.1// Bar B2: 1.0/5.5/1.0/3.3// Bar B3: 2.1/5.5/3.4/0.0//

(12) The chart of bar B2 is illustrated in FIG. 2.

(13) Bar B1 and bar B2 are each threaded 1 full, 1 empty, with a monofilament yarn made of polyester terephthalate (PET) having a diameter of 0.08 mm; bar B3, which gives rise to the barbs, is threaded 1 full, 3 empty, with a heat-fusible monofilament yarn made of polylactic acid having a diameter of 0.15 mm.

(14) For each of the two knits A and B, bar B3 is the one that leads to the formation of the barbs. Since the bars B3 are threaded in an identical manner for the two knits, and these bars have the same chart, the density of the barbs, once the loops have been melted, is the same for both knits.

(15) Once the loops have been melted and the barbs have been formed as described in WO 01/81667, the unrolling properties were evaluated after rolling these knits up on themselves, according to the following test: for each knit, samples of 5 cm×10 cm were cut, as shown in FIG. 3, each sample 1 of knit is rolled up on itself around a rod 3 having a diameter of 5 mm, the barbs 2 on the outside, along the direction of the arrow represented in FIG. 3. The roll obtained is then grasped with tweezers and inserted into a trocar having an internal diameter of 10 mm, then pushed until it comes out of the trocar.

(16) On exiting the trocar, as shown in FIG. 4A, the sample 1 in the form of a roll is mounted on a machine 4 equipped with a cell loaded to 25 N, comprising a fixed part 5 and a moving part 6. Around 2 cm of the sample 1 is unrolled and 1 cm of the sample 1 is fastened to the moving part 6. A constant extension rate of 50 mm/min is then applied to the sample 1 tested in order to unroll it, and the corresponding force F needed to maintain said constant extension rate is measured. The force F needed is recorded as a function of the length L of the unrolled portion of the sample 1 until sample 1 is completely unrolled, as shown in FIG. 4B. During the unrolling of the sample 1, the force force F needed may vary as a function of the resistance encountered. In particular, points of resistance, for which the force F for successfully unrolling the sample 1 must be increased, at least occasionally, may appear during the unrolling.

(17) These “points of resistance” are measured as follows: using measured values of the force F and length L of the unrolled portion as indicated above, the curve representing the force F, in newtons, is plotted as a function of the length L of the unrolled portion in mm, of the sample 1. Next, a threshold value is determined for the force F, for example 0.5 N. Each peak of the curve having a value greater than 0.5 N is considered to be a point of resistance. An example of such a curve, showing the peaks counted encircled, is represented in FIG. 5. By virtue of this curve, the maximum force needed, Fmax, is also determined.

(18) The results obtained for knit A according to the invention and comparative knit B are presented in Table I below:

(19) TABLE-US-00001 TABLE I Number of Number of “points of Average force Maximum Sample tests resistance” (N) force (N) Knit A 16 52 ± 11 1.13 ± 0.33 3.54 ± 0.85 Knit B 20 79 ± 8  4.01 ± 0.80 9.56 ± 1.68

(20) As it emerges from this table, the knit according to the invention (Knit A) has significantly fewer points of resistance than the knit from the prior art (Knit B). The average force needed to unroll the knit of the invention, after it has been rolled up on itself then passed through a trocar having an internal diameter of 10 mm is substantially lower than that needed to unroll the knit from the prior art. Likewise, the maximum force needed to unroll knit A according to the invention is practically divided by 3 compared to the maximum force needed in the case of the comparative knit B.

(21) Thus, the knit according to the invention can be unrolled easily after having been rolled up on itself then passed through a trocar having a diameter of 10 mm. The knit can thus be brought to an implantation site during laparoscopic or coelioscopic surgery for repairing a hernia, by means of a trocar, then it can be unrolled without the surgeon having to apply considerable force in order to deploy the knit and/or the prosthesis comprising said knit.