Tissue reinforcing material

Abstract

To provide a tissue reinforcing material that has excellent elasticity, and can reliably reinforce even the tissue that greatly expands and contracts.SOLUTION: A tissue reinforcing material is composed of a bioabsorbable material. An elongation rate in at least one direction is 200% or more when the stress is 1 N.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a tissue reinforcing material that is excellent in stretchability and can surely reinforce even a tissue that stretches greatly.

Background Art

[0002] In surgery, a reinforcing material may be used to reinforce tissue for the purpose of protecting the resection surface at the surgical site, preventing body fluid leakage, and reinforcing the suture site (for example, Patent Document 1). In order to suppress peeling from the tissue and obtain a high reinforcing effect, it is necessary to closely adhere the tissue reinforcing material to the tissue. For this purpose, high stretchability that can follow the shape of the tissue is required. However, although the non-woven fabric used in conventional tissue reinforcing materials has a certain degree of stretchability, it is insufficient in stretchability for use in reinforcing a tissue that stretches greatly such as the lung, and a tissue reinforcing material with higher stretchability is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a tissue reinforcing material that is excellent in stretchability and can surely reinforce even a tissue that stretches greatly.

Means for Solving the Problems

[0005] The present invention is a tissue reinforcing material made of a bioabsorbable material, and is a tissue reinforcing material having an elongation rate of at least 200% in at least one direction when a stress is 1 N. The present invention will be described in detail below.

[0006] As a result of intensive studies, the inventors of the present invention have found that by setting the elongation rate in at least one direction within a specific range, even when used for highly expandable and contractible tissues such as the lung, it can follow the movement of the tissue and reliably reinforce the tissue, thus completing the present invention.

[0007] The tissue reinforcing material of the present invention is made of a bioabsorbable material. By constructing the tissue reinforcing material with a bioabsorbable material, it is gradually absorbed by the living body after transplantation, and eventually disappears and is replaced by self-tissue. Therefore, the risk of reducing the foreign body reaction in the chronic stage and becoming a breeding ground for infection is reduced.

[0008] Examples of the bioabsorbable material include synthetic absorbable polymers such as polyglycolide, polylactide (D, L, DL forms), glycolide-lactide (D, L, DL forms) copolymer, glycolide-ε-caprolactone copolymer, lactide (D, L, DL forms)-ε-caprolactone copolymer, poly(p-dioxanone), and glycolide-lactide (D, L, DL forms)-ε-caprolactone copolymer. These may be used alone or in combination of two or more. Among them, polyglycolide, polylactide (L form), and lactide (D, L, DL forms)-ε-caprolactone copolymer are preferable because they can exhibit appropriate strength and flexibility and can cause an appropriate biological reaction to promote tissue repair. Polyglycolide is more preferable because it shows an appropriate degradation behavior. In addition, as the bioabsorbable material, natural absorbable polymers such as silk fibroin, collagen, gelatin, chitin, chitosan, and fibrin can also be used. Furthermore, the above synthetic absorbable polymer and the above natural absorbable polymer may be used in combination.

[0009] When using polyglycolide (a homopolymer or copolymer of glycolide) as the above-mentioned bioabsorbable material, the preferable lower limit of the weight-average molecular weight of polyglycolide is 30,000, and the preferable upper limit is 1,000,000. When the weight-average molecular weight of the above polyglycolide is 30,000 or more, sufficient strength as a tissue reinforcing material can be exhibited. When it is 1,000,000 or less, it causes an appropriate biological reaction to promote tissue repair, and by decomposing, there is no remaining as a foreign substance for a long time and it is quickly replaced by living tissue. A more preferable lower limit of the weight-average molecular weight of the above polyglycolide is 50,000, and a more preferable upper limit is 300,000.

[0010] The tissue reinforcing material of the present invention has an elongation rate of at least 200% in at least one direction when the stress is 1 N. Since the elongation rate of the tissue reinforcing material in at least one direction is within the above range, even when used for a tissue that greatly expands and contracts such as the lung, it can follow the movement and reliably reinforce the tissue. The above elongation rate is preferably 200% or more, and more preferably 300% or more. The above elongation rate can be obtained by measuring according to the method of 8.14 Tensile strength and elongation rate in the test method for fabric and knitted fabric of JIS L1096:2010 using a tensile testing machine (Autograph AGX-V, manufactured by Shimadzu Corporation), and reading the elongation rate when it elongates under a load of 1 N. Also, the elongation resistance value can be obtained by reading the stress at an arbitrary elongation rate from the measurement results obtained by the same method.

[0011] The tissue reinforcing material of the present invention is preferably a non-woven fabric obtained by false-twisting a thread made of a bioabsorbable material and needle-punching a circular knitted fabric. False twist refers to a process of twisting long fibers, setting them with heat, and then releasing the twist. When false twist is applied, the yarn curls like permed hair and becomes bulky. By using such false-twisted yarn, it is possible to impart stretchability in the advancing direction of the yarn (the longitudinal direction of the yarn). In addition, the knitted fabric formed by circular knitting has stretchability in the horizontal direction (hereinafter also referred to as the lateral direction) with respect to the knitting advancing direction. Furthermore, by needle punching the circular knitted fabric made of the false-twisted yarn to form a non-woven fabric, it is possible to obtain a tissue reinforcing material that has the properties of a non-woven fabric and can stretch significantly not only in the lateral direction but also in the longitudinal direction.

[0012] The yarn made of the bioabsorbable material that constitutes the above-mentioned circular knitted fabric may be monofilament or multifilament, but since it is made into a non-woven fabric by needle punching, it is preferably multifilament.

[0013] The thickness of the yarn made of the bioabsorbable material that constitutes the above-mentioned circular knitted fabric is not particularly limited, but it is preferably 10 denier or more, more preferably 14 denier or more, preferably 40 denier or less, and more preferably 35 denier or less.

[0014] The method for manufacturing the yarn made of the bioabsorbable material that constitutes the above-mentioned circular knitted fabric is not particularly limited, and conventionally known spinning methods such as the melt spinning method can be used.

[0015] The number of twists during the above-mentioned false twist is not particularly limited, but it is preferably 100 T / m or more and 2000 T / m or less. When the number of twists of the above-mentioned false twist is within the above range, the stretchability can be further enhanced. The number of twists of the above-mentioned false twist is more preferably 200 T / m or more and more preferably 1000 T / m or less. Note that T / m represents the number of twists per meter.

[0016] The above-mentioned circular knitted fabric preferably has a stitch density of 6 stitches / 0.5 inch or more and 25 stitches / 0.5 inch or less. When the density of the cylinder-knitted fabric is within the above range, the degree of expansion and contraction of the obtained fabric reinforcing material in the transverse direction can be further increased. The density of the above cylinder-knitted fabric is more preferably 6 stitches / 0.5 inch or more, still more preferably 8 stitches / 0.5 inch or more, preferably 25 stitches / 0.5 inch or less, and still more preferably 20 stitches / 0.5 inch or less.

[0017] The conditions of the above cylinder knitting and needle punching are not particularly limited, and conventionally known conditions can be appropriately used within the range where the effects of the present invention can be exhibited.

[0018] It is also preferable that the fabric reinforcing material of the present invention is a non-woven fabric formed by needle punching a fabric knitted by milling a thread made of a bioabsorbable material. Since the mill-knitted fabric has elasticity in the transverse direction of knitting, by needle punching the mill-knitted fabric into a non-woven fabric shape, it is possible to obtain a fabric reinforcing material that has the properties of a non-woven fabric and can greatly expand and contract in the transverse direction.

[0019] As the thread made of the bioabsorbable material constituting the above mill-knitted fabric, the same thread as the thread made of the bioabsorbable material constituting the above cylinder-knitted fabric described above can be used.

[0020] The conditions of the above milling are not particularly limited, and conventionally known conditions can be appropriately used within the range where the effects of the present invention can be exhibited.

[0021] The conditions for needle punching the above mill-knitted fabric are not particularly limited, and conventionally known conditions can be appropriately used within the range where the effects of the present invention can be exhibited.

[0022] It is also preferable that the fabric reinforcing material of the present invention is a non-woven fabric formed by false-twisting a thread made of a bioabsorbable material and then needle punching a mill-knitted fabric. As described above, while the yarn subjected to false twisting can impart stretchability in the yarn running direction, the mill knitted fabric has stretchability in the transverse direction of knitting. Therefore, by mill knitting the false twisted yarn and needle punching it, a tissue reinforcing material that is a non-woven fabric and can stretch greatly in both the longitudinal and transverse directions can be obtained. Regarding the conditions for the above false twisting, mill knitting, and needle punching, the above-mentioned conditions can be used.

[0023] The basis weight of the tissue reinforcing material of the present invention is not particularly limited, but the preferable lower limit is 5 g / m 2 and the preferable upper limit is 300 g / m 2 . When the basis weight of the non-woven fabric is 5 g / m 2 or more, the strength of the tissue reinforcing material is further improved, and when it is 300 g / m 2 or less, the adhesiveness to the tissue can be further enhanced. A more preferable lower limit of the basis weight of the tissue reinforcing material is 10 g / m 2 and a more preferable upper limit is 100 g / m 2 .

[0024] As a method for producing the tissue reinforcing material of the present invention, for example, a method of false twisting a yarn made of a bioabsorbable material, circular knitting the false twisted yarn, and then needle punching it, a method of mill knitting a yarn made of a bioabsorbable material and then needle punching it, a method of false twisting a yarn made of a bioabsorbable material, mill knitting the false twisted yarn, and then needle punching it, etc. can be mentioned. A method for producing a tissue reinforcing material having a step of false twisting a yarn made of a bioabsorbable material, a step of circular knitting the false twisted yarn made of the bioabsorbable material to form a knitted fabric, and a step of needle punching the knitted fabric, a method for producing a tissue reinforcing material having a step of mill knitting a yarn made of a bioabsorbable material to form a knitted fabric and a step of needle punching the knitted fabric, and a method for producing a tissue reinforcing material having a step of false twisting a yarn made of a bioabsorbable material, a step of mill knitting the false twisted yarn made of the bioabsorbable material to form a knitted fabric, and a step of needle punching the knitted fabric are also one of the present inventions. Regarding the thread, false twist, tubular knitting, milling knitting, and needle punching made of the above bioabsorbable material, the same materials and conditions as those of the tissue reinforcing material of the present invention can be used.

[0025] The tissue reinforcing material of the present invention is used for hemostasis, prevention of air leakage, and prevention of body fluid leakage of damaged or weakened organs and tissues in the surgical field. Among them, since the tissue reinforcing material of the present invention is excellent in stretchability, it can be suitably used for tissues with large expansion and contraction such as the lungs. The biological tissue reinforcing material of the present invention can be easily attached, for example, by immersing the biological tissue reinforcing material in physiological saline and then applying it to the affected area. In addition, when there is blood or body fluid in the affected area, the adhesive force can also be expressed by absorbing these.

Effects of the Invention

[0026] According to the present invention, it is possible to provide a tissue reinforcing material that is excellent in stretchability and can surely reinforce even tissues that expand and contract greatly.

Modes for Carrying Out the Invention

[0027] Hereinafter, the embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited only to these examples.

[0028] (Example 1) Polyglycolic acid chips were melt-spun and drawn to obtain polyglycolic acid yarn with 12 filaments and 31.8 denier. The obtained yarn was twisted at a twist number of 1000 T / m, heat-treated at 140°C for 1 hour, and then false-twisted by releasing the twist. Next, the false-twisted yarn was tubular-knitted on an 18-gauge tubular knitting machine under the condition of 12 stitches / 0.5 inch to produce a tubular plain knitted fabric (tubular knitted fabric), and the obtained tubular knitted fabric was needle-punched to obtain a tissue reinforcing material with a thickness of 0.167 mm.

[0029] (Example 2) A tissue reinforcing material was obtained in the same manner as in Example 1 except that the twist number of the false twist was 2000 T / m.

[0030] (Example 3) A fabric reinforcing material was obtained in the same manner as in Example 1, except that the number of twists of the false twist was 250 T / m.

[0031] (Example 4) A fabric reinforcing material was obtained in the same manner as in Example 1, except that the stitch density of the circular knitted fabric was 18 stitches / 0.5 inch.

[0032] (Example 5) A fabric reinforcing material was obtained in the same manner as in Example 2, except that the stitch density of the circular knitted fabric was 17 stitches / 0.5 inch.

[0033] (Example 6) A yarn made of polyglycolide was obtained in the same manner as in Example 1. Next, the obtained yarn was milled under the conditions of 16 gauge and 14 stitches / 0.5 inch to obtain a knitted fabric. The obtained knitted fabric was needle punched to obtain a fabric reinforcing material with a thickness of 0.192 mm.

[0034] (Comparative Example 1) Polyglycolic acid chips were melt spun and drawn to obtain a polyglycolic acid yarn of 12 filaments and 31.8 denier. This was knitted on a circular knitting machine to obtain a tubular plain knitted fabric. This circular knitted fabric was needle punched to obtain a fabric reinforcing material with a thickness of 0.150 mm in the state where the knitting pattern was hardly visible, i.e., a non-woven fabric.

[0035] (Measurement of elongation rate) Using a tensile testing machine (Autograph AGX-V, manufactured by Shimadzu Corporation), the elongation rate and stress in the warp direction and weft direction were measured according to the method of 8.14 Tensile strength and elongation rate in the test method for fabrics and knitted fabrics of JIS L1096:2010. Samples were cut out from the fabric reinforcing materials obtained in the examples, each with a width of 20 mm × a length of 40 mm in the longitudinal and transverse directions, set on the tensile testing machine with a chuck distance of 20 mm, and after elongation was carried out at a tensile speed of 100 mm / min until the sample broke, the elongation rate at a low stress (1 N) was read. The results are shown in Table 1.

[0036]

Table 1

[0037] (Measurement of stress) Measurement was carried out until the sample broke in the same way as the elongation rate, and then the stress at a constant elongation (200%) was read. The results are shown in Table 2.

[0038]

Table 2

Industrial Applicability

[0039] According to the present invention, it is possible to provide a tissue reinforcing material that is excellent in stretchability and can surely reinforce even a tissue that stretches greatly.

Claims

**Claim 1** A tissue reinforcing material made of a bioabsorbable material, wherein the tissue reinforcing material is a nonwoven fabric formed by false-twisting a thread made of a bioabsorbable material, knitting it by circular knitting, and then needle-punching the knitted fabric, and the elongation rate in at least one direction when the stress is 1 N is 200% or more. **Claim 2** The tissue reinforcing material according to Claim 1, wherein the bioabsorbable material is polyglycolide. **Claim 3** A method for manufacturing a tissue reinforcing material, comprising a step of false-twisting a thread made of a bioabsorbable material, a step of circular knitting the false-twisted thread made of the bioabsorbable material to form a knitted fabric, and a step of needle-punching the knitted fabric. **Claim 4** A method for manufacturing a tissue reinforcing material, comprising a step of false-twisting a thread made of a bioabsorbable material, a step of milling-knitting the false-twisted thread made of the bioabsorbable material to form a knitted fabric, and a step of needle-punching the knitted fabric.

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