JPH04250167A - Medical prosthesis material - Google Patents

Abstract

PURPOSE:To provide a soft medical prosthesis material for artificial blood vessel or artificial trachea which has internal cavity holding force and airtightness just after internal transplantation to eliminate cares of blood leak and bacterial infection, and is integrated with and adhered to a biological tissue after the lapse of time from the internal transplantation, an prevents a granulation tissue from entering the hollow inner par of a tubular body so that the flow of blood or air is never prevented. CONSTITUTION:In a medical prosthesis material consisting of a knitted fabric or non woven fabric formed from a biologically absorptive polymer yarn and a biologically non-absorptive polymer yarn, the biologically non-absorptive polymer yarn is a polyolefin fiber. Just after the internal transplantation, the material has airtightness and liquid-tightness because it consists of the biologically absorptive polymer yarn and the biologically non-absorptive polymer yarn, the biologically absorptive polymer yarn is thereafter decomposed in the living body, a granulation tissue bites into the bridle of the biologically non-absorptive polymer yarn and forms a biological tissue while filling the decomposed and absorbed yarn part.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to medical prosthetic materials.
More specifically, the present invention relates to a medical prosthetic material for repairing and restoring surface tissues such as the trachea, blood vessels, or body tissues such as the heart that have been excised due to lesions or damage.

0002

[Prior Art] Garnet has been used as a medical prosthetic material for a long time.
Gauze is used to absorb exudate from the wound surface and prevent the invasion of bacteria from the outside, but it has the disadvantage that the granulation tissue on the wound surface digs into the gauze and damages the granulation tissue when changing the dressing. There are also cloth-like or tubular medical prosthetic materials made by weaving or knitting polyester or fluororesin threads.
In order to stop bleeding after surgery, it was necessary to seal the weave or stitches in advance with blood coagulation because blood leaks through the weave or stitches.

[0003] Furthermore, Japanese Patent Application Publication No. 501118/1997 discloses that by using a tubular body of woven fabric with a new weaving pattern of alternating plain weave/twill weave as a medical prosthetic material, no blood coagulation is caused on the surface. Artificial blood vessels with flexibility and flexibility have also been introduced. Furthermore, a material in which coagulation factor XIII is immobilized on the wall of a tubular artificial organ was introduced in JP-A-57-115250 as a medical prosthetic material for an artificial trachea to be implanted after resection of the affected area due to laryngeal cancer, bronchial tumor, etc. By increasing the rate of organization after in-vivo transplantation, artificial organs without the risk of thrombotic occlusion, ulcer formation, or stenosis have been created. In addition, artificial tracheas made of silicone are commercially available, which use fiber cloth as a medical prosthetic material on the wall of the spiral wire to prevent the leakage of exhaled and inhaled air. Japanese Patent Publication No. 60-43981 introduces a method of making an artificial blood vessel using a tubular fibrous body made of a nonwoven fabric spun and formed.

0004

[Problems to be Solved by the Invention] However, medical prosthetic materials for artificial tracheas made of knitted fabrics and non-woven fabrics are low-density products that take flexibility into account, and therefore have insufficient airtightness, resulting in air leakage from the inside of the tubular body. There is a high risk that they will pass through medical prosthetic materials and invade body tissues, causing bacterial infection and inflammation. In addition, by increasing the density of knitted fabrics and non-woven fabrics, or by coating their surfaces to improve their airtightness and liquidtightness, they become rigid, and do not adapt to body tissues, do not allow endothelial cells to invade, and do not infiltrate surrounding tissues. It will cause obstacles. On the other hand, silicone artificial tracheas that place emphasis on flexibility, airtightness, and fluid tightness have the disadvantage that granulation tissue does not penetrate into the interior of the medical prosthetic material, and the artificial trachea does not integrate with the surrounding body tissue and deviates from it. was there.

[0005] Furthermore, artificial blood vessels made of woven or non-woven fabrics with novel weave patterns have improved flexibility and are easier to handle than conventional ones before being implanted in the body, but if they adhere to granulation tissue after being implanted in the body, It lost its flexibility and could not move in conjunction with the body's movements, so it did not integrate with the surrounding tissue, and there was a risk of inflammation.

[0006] The present inventors have developed a knitted fabric or non-woven fabric formed from bioabsorbable polymer threads and non-bioabsorbable polymer threads as a medical prosthetic material that improves the drawbacks of these conventional medical prosthetic materials. It has been developed and a patent application has already been filed (Patent Application Hei 2).
-215398 and Japanese Patent Application No. 2-250763)
. The present inventors have investigated the characteristics of non-bioabsorbable polymer thread materials used in these knitted fabrics or non-woven fabrics as medical prosthetic materials, and have found that depending on the thread material, granulation tissue may form in the threads of the tubular body. It has been found that it not only digs into the hollow part, but also extends into the hollow part, obstructing the flow of blood and air in the hollow part of the blood vessels and trachea.

[0007] The purpose of the present invention is to have a lumen retaining force and be airtight immediately after implantation in the body, and to integrate and adhere to living tissue after implantation in the body, and to prevent granulation tissue from penetrating into the hollow interior of the tubular body. It is an object of the present invention to provide a medical prosthetic material that is flexible and flexible.

[0008]

[Means for Solving the Problems] The present invention provides a medical prosthetic material consisting of a knitted fabric or a non-woven fabric formed from a bioabsorbable polymer thread and a bionon-absorbable polymer thread. This is a medical prosthetic material characterized in that it is a polyolefin fiber.

The present invention also provides a medical prosthetic material, in which the knitted fabric is formed from a composite yarn consisting of doubled yarns or twisted yarns.

Furthermore, the present invention provides the above-mentioned medical prosthetic material, in which the knitted fabric is a mixed knit or mixed fabric of bioabsorbable polymer threads and non-bioabsorbable polymer threads.

Furthermore, in the medical prosthesis material of the present invention, the average pore diameter of the knitted fabric or nonwoven fabric formed by the non-bioabsorbable polymer yarns remaining after the bioabsorbable polymer yarns are absorbed in the body is A medical prosthetic material in which at least 20% of the pores of at least 110 μm are present in the fabric.

Furthermore, the present invention provides a medical prosthetic material, in which the surface of the composite yarn, nonwoven fabric, or knitted fabric is coated with protein.

[0013]

[Operation] Immediately after implantation into the body, the medical prosthetic material of the present invention is a knitted fabric or non-woven fabric composed of bioabsorbable polymer threads and non-bioabsorbable polymer threads, which requires relatively airtightness and liquidtightness. Because it is made of 100% polyurethane, fine substances such as bacteria are prevented from passing through the knitted fabric or nonwoven fabric. On the other hand, the bioabsorbable polymer threads in the body are gradually degraded and absorbed within the body, and the granulation tissue bites into the threads of the non-bioabsorbable polymer threads of knitted fabrics or non-woven fabrics, and the parts of the threads are degraded and absorbed. It is thought that biological tissue is formed while filling the tissue, and eventually the coarse-density knitted fabric or nonwoven fabric made of polyolefin yarn, which is a non-bioabsorbable polymer yarn, forms a tight composite with the biological tissue. In this case, since polyolefin fibers have better adhesion to the granulation tissue than threads of other materials, it is thought that only the granulation tissue does not stretch further and impede the flow of fluid in the hollow part of the tubular body.

[0014]

[Examples] The present invention will be explained below with reference to Examples.

1 and 2 are enlarged plan views of a woven fabric showing an example of the medical prosthetic material of the present invention, FIG. 3 is an enlarged plan view of a nonwoven fabric showing an example of the medical prosthetic material of the present invention, and FIG. 1 is a partially cutaway sectional view of an artificial blood vessel formed using the medical prosthetic material of the present invention.

[0016] In the figure, the threads indicated by white lines are non-bioabsorbable polymer threads;
Diagonally shaded threads are bioabsorbable polymer threads 1-8 and 33-3
6 is a warp, 11 to 18 and 37 to 40 are wefts, 21 is an annular rib, and 22 is a knitted fabric.

FIG. 1 shows a medical prosthetic material made of a 2/2 plain weave fabric. That is, the warp 1 made of bioabsorbable polymer thread and the warp 2 made of bionon-absorbable polymer thread are:
Above the weft 11 made of bioabsorbable polymer thread and the weft 12 made of non-bioabsorbable polymer thread, then below the weft 13 made of bioabsorbable polymer thread and the weft 14 made of non-bioabsorbable polymer thread. The weft 15 is made of a bioabsorbable polymer yarn, and the weft 16 is made of a non-bioabsorbable polymer yarn. Figure 1
Although plain weave was explained as the fabric, twill weave, satin weave, etc. may also be used. The knitted fabric is warp-knitted or weft-knitted, and is knitted into a tubular or planar shape using various knitting methods such as tuck knitting, flat knitting, double-sided knitting, and purl knitting.

The average pore diameter of the pores of the knitted fabric formed by the non-bioabsorbable polymer yarns remaining after the bioabsorbable polymer yarns are decomposed and absorbed in the body, for example, the distance L between the warp threads 4 and 6 is at least 110 μm, preferably 1
A thickness of 50 to 1000 μm is preferable because granulation tissue invades the spaces between the threads and fixes the medical prosthetic material in the body. The distance L between non-bioabsorbable polymer threads is at least 110
μm present in at least 20% of woven or knitted fabrics,
Preferably, when it is present in an amount of 40 to 70%, the woven or knitted fabric is firmly fixed to the body tissue. Multifilament or monofilament yarns are used for the warp and weft yarns, and false twisted yarns are particularly preferred because they improve airtightness and flexibility.

FIG. 2 shows a medical prosthetic material made of a 1/1 plain weave fabric, in which the warp is made of a combination of bio-non-absorbable polymer threads 31 and bio-absorbable polymer threads 32, and the weft is a bio-absorbable polymer thread 31. It consists of a twisted yarn of a non-absorbable polymer yarn 31 and a bioabsorbable polymer yarn 32. In other words, the warp 33 is woven by sequentially passing over the weft 37, then under the weft 38, then over the weft 39, and so on. In FIG. 2, a plain weave is used as the fabric, but a weave such as twill weave or satin weave may be used. Further, the knitted fabric is knitted into a tubular or flat shape using a warp knitting method, a weft knitting method, or the like. The average pore diameter of the pores of the knitted fabric formed by the bio-non-absorbable polymer yarns, for example, the distance L between the bio-non-absorbable polymer yarns in FIG. 2, is at least 110 μm as in FIG. 1,
Preferably, the thickness is 150 to 1000 μm because granulation tissue invades the spaces between the threads to quickly form body tissue and fix the medical prosthetic material in the body.

[0020] When at least 20%, preferably 40 to 70%, of pores with an average pore diameter of at least 110 μm are formed by non-bioabsorbable polymer threads in the knitted fabric, the medical prosthetic material is firmly bonded to body tissue. Fixed. The average pore diameter formed by the non-bioabsorbable polymer thread is 110μ
If it is less than m, it becomes difficult for granulation tissue to invade between the fibers, and it tends to become difficult for the fibrous tissue to be fixed in the body.

[0021] Knitted fabrics are formed from composite yarns consisting of plied yarns or plied twisted yarns, but the fiber diameters of the non-bioabsorbable polymer yarns and the bioabsorbable polymer yarns may be changed, or the distance between the warp yarns or the distance between the weft yarns may be changed. By changing the number of bioabsorbable polymer threads and bioabsorbable polymer threads constituting the plied or twisted threads, the number of voids in the pores formed by the non-bioabsorbable polymer threads can be reduced. The size can be adjusted. In Fig. 2, the warp is a double yarn, and the weft is a twisted yarn.
The knitted fabric may be a knitted fabric or a woven fabric made of double or twisted yarns for both the warp and weft, or one in which only one of the warp and weft uses double or twisted yarn, and the other uses non-bioabsorbable polymer yarn. It may also be a knitted or woven fabric. The twist angle of the twisted yarn is the angle indicated by the twist direction with respect to the cross-sectional direction of the fibers, that is, expressed as tan θ, it is 45 to 88 degrees, preferably 65 to 85 degrees.

FIG. 3 is an enlarged plan view of a medical prosthetic material made of a nonwoven fabric of bioabsorbable polymer threads and non-bioabsorbable polymer threads. That is, a black line thread 42 made of bioabsorbable polymer thread and a white line thread 41 made of bionon-absorbable polymer thread.
This means that the threads are intertwined with each other and partially fixed at their intersections. Non-woven fabrics are produced by spinning bioabsorbable polymer threads and non-bioabsorbable polymer threads from different nozzles with static electricity, air flow or liquid flow, and then the fibers are spun on a conveyor or on the surface of a rotating cylindrical or cylindrical mandrel. The fibers are then dispersed in a planar shape and then partially fixed in the cross-sectional direction by a physical method such as a needling method or a water jet method. Other methods for joining fibers include attaching the intertwined points of fibers to each other using heat,
The intertwined points of fibers can also be fixed by chemical methods such as chemical treatment and solvent treatment. Further, the nonwoven fabric dispersed on the surface of the mandrel becomes a tubular nonwoven fabric by removing the mandrel.

Although the structure of the nonwoven fabric is explained using long fibers in FIG. 3, it may also be a nonwoven fabric made of short fibers, and may be formed into a tubular or planar shape. The average pore diameter of the non-woven fabric formed by the non-bioabsorbable polymer threads remaining after the bioabsorbable polymer threads are decomposed and absorbed in the body, for example the shaded area in FIG. 3, is at least 110 μm, preferably 150 μm. ~
A thickness of 1000 μm is preferable because granulation tissue invades the spaces between the threads to quickly form body tissue and fix the medical prosthetic material in the body. The pores having such an average pore diameter account for at least 20% of the nonwoven fabric, preferably 40% to 40%.
It is 70%. Monofilaments are usually used as bioabsorbable polymer threads and non-bioabsorbable polymer threads, but multifilaments may also be used.

Bioabsorbable polymer threads include polylactide, polyglycolic acid, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polyamino acid,
Examples include threads made of polycaprolactone, polydioxanone and copolymers thereof, ethylene carbon monoxide copolymers, cellulose derivatives or copolymers thereof, vinyl acetate and unsaturated carboxylic acid copolymers, and the like.

[0025] Examples of the non-bioabsorbable polymer thread include threads made of polyethylene, polypropylene, polybutene, polypentene alone or copolymers thereof, and crystalline polypropylene fibers are particularly preferred. These fibers also contain mixtures of additives and other resins. The fiber diameter of a single yarn of polyolefin fiber is 0.1 to 1
00 μm, preferably 1.0 to 40 μm. When the fiber diameter of a single yarn exceeds 100 μm, the knitted or nonwoven fabric becomes stiff and tends to cause inflammation when implanted into the body, while when it is less than 0.1 μm, it tends to be difficult to mold the fiber.

[0026] The bulk density of the nonwoven fabric made of bioabsorbable polymer threads and non-bioabsorbable polymer threads is 0.05 to 0.60.
g/cm3. Bulk density of non-woven fabric is 0.60g/c
If it exceeds m3, the nonwoven fabric tends to become stiff and tends to cause inflammation when implanted into the body. Bulk density is 0.
If it is less than 0.05 g/cm3, the mechanical properties of the nonwoven fabric tend to deteriorate. The thickness of the nonwoven or knitted fabric is at least 0.1 mm, preferably 1 to 10 mm. When the thickness of the nonwoven fabric or knitted fabric is less than 0.1 mm,
Durability tends to deteriorate.

Bioabsorbable polymer threads and non-bioabsorbable polymer threads may be coated with proteins on their surfaces in the form of threads, and then formed into knitted fabrics or non-woven fabrics, or coated with proteins on their surfaces in the form of knitted fabrics or non-woven fabrics. By coating with the material, it is possible to promote bioadhesion on the surface of the medical prosthetic material and maintain airtightness. Examples of proteins include collagen, gelatin, albumin, fibrinogen, globulin, and fibronectin. To coat the surface of a fabric or yarn with a protein coating, the fabric or yarn is immersed in a protein solution, rinsed several times with water at room temperature, and dried to form a coating.

FIG. 4 shows an artificial blood vessel formed using the medical prosthetic material of the present invention, in which, for example, a knitted fabric 22 of non-bioabsorbable polymer yarn and bioabsorbable polymer yarn is wound in a helical shape. It is a tubular body having an annular rib 21 formed therein. The outer surface of the tubular body may be covered with a coating of protein such as collagen or gelatin, and the inner surface may be covered with a coating of antithrombotic material. When such an artificial blood vessel is incorporated into the body, the bioabsorbable polymer thread, which is one component of the knitted fabric that makes up the tubular body, breaks down the main chain of the polymer over time, decomposes, and is absorbed into the body. At the same time, the granulation tissue bites into the voids of the non-bioabsorbable polymer threads, and the artificial blood vessel is tightly fixed to the living tissue. Artificial blood vessels, which initially had a high density and were rather rigid due to the requirements for airtightness and liquidtightness, became flexible as the bioabsorbable polymer thread was absorbed within the body. Disorders caused by foreign substances such as blood vessels entering the body are alleviated, and inflammation does not occur.

[0029] In addition, for example, the skeleton has an inner diameter of 20 to 30 m.
An artificial trachea is formed by covering the outer surface and/or inner surface of the body of a porous cylindrical body made of fluororesin and having a length of 10 to 50 mm and a thickness of 0.1 mm with the medical prosthetic material of the present invention. For example, an artificial trachea is formed by covering the skeleton of an artificial trachea with a tubular body made of a knitted fabric of bioabsorbable polymer threads and non-bioabsorbable polymer threads. The outer surface of the fabric may be coated with a protein coating such as collagen or gelatin. The artificial trachea originally transplanted into the body is made of a high-density knitted fabric, so it maintains an airtightness to prevent exhaled and inhaled air from escaping, and works effectively as an artificial trachea and has good liquid-tightness, so it can prevent external bacteria. does not pass through knitted fabrics and cause bacterial infection. Gradually, the bioabsorbable polymer threads that make up the knitted fabric are decomposed and absorbed within the body, and the granulation tissue bites into the gaps in the remaining non-bioabsorbable polymer threads and is tightly fixed to the living tissue.
Forms a flexible composite.

Examples 1 to 5

Polypropylene (hereinafter referred to as PP) multifilament 18d/6f and polyglycolic acid (hereinafter referred to as PP)
Multifilament 12d/6f (referred to as PGA) was used to double the yarns and used as the warp of the 1/1 plain weave shown in FIG. Thereafter, this doubled yarn was twisted in the S direction at 200 T/M to obtain a twisted yarn, which was used as the weft of the plain weave shown in FIG. When forming the fabric shown in Figure 2 using these warp and weft yarns,
A woven fabric was formed by changing the distance L between the PP fibers of the warp as shown in Table 1. After applying a 10% by weight aqueous solution of collagen to the surface of the fabric formed in this way and drying it,
The fabric was implanted subcutaneously on the back of a dog, and after 6 weeks had passed, the implantation status of the fabric was visually evaluated as described below. The results are shown in Table 1.

[0032] The granulation tissue satisfactorily penetrates into the voids of the fabric, and the casual fabric is fixed to the body tissue. △ Granulation tissue has invaded the fabric voids, but the fabric is easily peeled off. × No invasion of granulation tissue into the fabric voids is observed.

Comparative example 1

In the fabric shown in FIG. 2, using only PP fibers, 1
/1 plain weave fabric was molded. The PP fiber used was 7
It was a 2d/24f multifilament. The distance L between PP fibers (distance between adjacent fibers in Figure 2) is 86 μm
Met. This fabric was implanted subcutaneously on the back of a dog in the same manner as in Example 1, and the implantation status after 6 weeks is shown in Table 1.

[0035]

[Table 1]

As is clear from Table 1, in the fabric of Comparative Example 1 in which the distance between fibers formed by PP fibers was less than 100 μm, no intrusion of granulation tissue was observed in the fiber pores; In the fabric of Example 5, intrusion of granulation tissue into the fiber pores was observed, but it seems that a long period of time is required for the fabric to be fixed to body tissue.

Example 6

[0038] A doubled yarn formed using polypropylene fibers 75d/24f and polyglycolic acid fibers 18d/6f was used for the warp and weft, and the inner diameter was 9 mm and the length was made of 1/1 plain weave as shown in Fig. 2. A 6 cm tubular body was manufactured on a handloom. Thereafter, a 10% by weight aqueous collagen solution was applied to the outer surface of the tubular body to form a collagen coating. The distance L between PP fibers was 433 μm. This tubular body was transplanted into the descending thoracic aorta of a dog, and after 3 months had elapsed, the status of the transplantation of the tubular body was visually evaluated as follows. The results are shown in Table 2.

[0039] A neointima is formed on the wall of the tubular body, and no granulation tissue is generated in the hollow part of the tubular body. △ Short granulation tissue is observed around the inner wall of the tubular body. × Granulation tissue is generated across the hollow cross section of the tubular body.

Example 7

High density polyethylene fiber (density 0.96g
A tubular body was formed in the same manner as in Example 6 using a doubling yarn formed using 70d/12f (hereinafter referred to as PE) and 18d/6f polyglycolic acid filament as the warp and weft. The distance L between PE fibers was 513 μm. This tubular body was transplanted into the descending thoracic aorta of a dog in the same manner as in Example 6, and
Table 2 shows the transplantation status of the tubular body after several months had passed.

Comparative example 2

Polyethylene terephthalate fiber (hereinafter referred to as P
A tubular body was formed in the same manner as in Example 6, using a doubling yarn formed using 75d/24f (referred to as ET) and polyglycolic acid filament 18d/6f as the warp and weft. The distance L between the PET fibers was 396 μm. This tubular body was transplanted into the descending thoracic aorta of a dog in the same manner as in Example 6, and the transplantation status of the tubular body after 3 months was shown in Table 2.
Shown below.

Comparative example 3

[0045] Nylon 66 fiber (hereinafter referred to as NY) 70
d/36f and polyglycolic acid filament 18d/
A tubular body was formed in the same manner as in Example 6, using doubling yarns formed using 6f as the warp and weft. The distance L between NY fibers was 421 μm. This tubular body was transplanted into the descending thoracic aorta of a dog in the same manner as in Example 6, and the transplantation status of the tubular body after 3 months is shown in Table 2.

[0046]

[Table 2]

As is clear from Table 2, when the tubular bodies of Examples 6 and 7 of the present invention are used as artificial blood vessels, granulation tissue does not seep into the hollow part of the tubular body, and no granulation tissue is observed on the wall of the tubular body. Formation of neointima was observed.

[0047]

[Effect] Immediately after implantation into the body, the medical prosthetic material of the present invention is made of a knitted fabric or non-woven fabric of bioabsorbable polymer threads and non-bioabsorbable polymer threads, so it has a high density and pores are filled with blood and tissue cells. For example, in artificial blood vessels and artificial tracheas, concerns about intraductal blockage and bacterial infection due to blood leakage are significantly reduced. Then, as time passes, the bioabsorbable polymer threads are broken down and bioabsorbed within the body, and in their place, granulation tissue bites into the gaps between the non-bioabsorbable polymer threads and becomes tightly immobilized with the living tissue. , the medical prosthetic material is stabilized by being incorporated into living tissue. Moreover, even if it is transplanted into the body for a long period of time, the granulation tissue will not extend into the hollow part of the artificial blood vessel or artificial trachea and impede the flow of blood and air.

[Brief explanation of the drawing]

FIG. 1 is an enlarged plan view of a fabric illustrating an example of the medical prosthetic material of the present invention.

FIG. 2 is an enlarged plan view of a fabric illustrating an example of the medical prosthetic material of the present invention.

FIG. 3 is an enlarged plan view of a nonwoven fabric showing an example of the medical prosthetic material of the present invention.

FIG. 4 is a partially cutaway sectional view of an artificial blood vessel formed using the medical prosthetic material of the present invention.

[Explanation of symbols]

1-8 Warp 11-18 Weft 21 Annular rib 22
Knitting 33-36
Warp 37-40 Weft

Claims (5)

[Claims] Claim 1: In a medical prosthetic material consisting of a knitted fabric or a non-woven fabric formed from a bioabsorbable polymer thread and a bionon-absorbable polymer thread, the non-bioabsorbable polymer thread is a polyolefin fiber. Characteristic medical prosthetic materials. 2. The medical prosthetic material according to claim 1, wherein the knitted fabric is formed of a composite yarn consisting of plied yarns or plied twisted yarns. 3. The medical prosthetic material according to claim 1, wherein the knitted fabric is a mixed knitted fabric or a mixed fabric of bioabsorbable polymer threads and non-bioabsorbable polymer threads. 4. The average pore diameter of the knitted fabric or nonwoven fabric formed by the non-bioabsorbable polymer yarn remaining after the bioabsorbable polymer yarn is absorbed in the body is at least 110 μm.
The medical prosthetic material according to any of claims 1 to 3, wherein at least 20% of the pores are present in the knitted fabric. 5. The medical prosthetic material according to claim 1, wherein the surface of the composite yarn, nonwoven fabric, or knitted fabric is coated with protein.