MXPA01004077A - Implant for implantation in humans or animals comprising flexible, thread-shaped elements - Google Patents

Abstract

The present invention relates to a porous, in humans or animals biodegradable, biocompatible implant for implantation in humans or animals, which implant comprises flexible, thread-shaped elements. The thread-shaped elements consist of a number of thread bundles (1) containing up to several thousand threads (2) which in turn contain 50 to 500 filaments with a combined density of 5 to 120 tex. The thread bundles (1) have a twist of 0 to 150 revolutions per metre and are held together by weft threads (3) with a distribution density of a few threads per cm up to roughly 100 threads per cm calculated in the longitudinal direction of the thread-shaped element.

Description

IMPLANT. FOR THE IMPLEMENTATION IN HUMAN AND ANIMAL BEINGS. WHICH INCLUDES FLEXIBLE ELEMENTS IN THE FORM OF THREADS TECHNICAL FIELD The present invention relates to an implant, for implantation, in particular, in humans, which comprises flexible elements, in the form of threads, and is particularly suitable for replacing broken joint ligaments. This implant attempts to be temporary and which disintegrates over time into fragments that are small enough so that they can be transported away by blood and excreted through the kidneys.

State of the Art - Every year, millions of people are affected by damage to the articular ligaments and tendons. A damaged ligament can be treated by surgical intervention or conservative therapy. Despite the fact that orthopedic experts agree that surgical intervention is preferred in most cases, conservative therapy remains the most frequently used alternative. A major reason for this is that existing operating techniques, which use existing implants, are considered inadequate.

A common feature of all types of reconstruction is that the surgeon has to use some form of replacement material to replace the damaged tissue. The most frequently used type of replacement material is the patient's own tissue (autograft), which the surgeon takes from other parts of the body. This tissue is often supplemented with a synthetic material as reinforcement (implant enhancement). Alternatively, the use is of only a synthetic material (prosthetic implant). Implant materials that have been treated in the past years, in addition to the autografts, are, among others, the tendons of animals (xenografts), deceased humans (allografts), synthetic materials in the form of non-degradable bands (Dacron, polyethylene, polypropylene, carbon fibers, polytetrafluoroethylene) and a degradable band made of polydioxanone. Temporary implants, for implantation in humans or animals, comprising flexible elements in the form of threads, are previously known. One of them is described in the Swedish patent specification 457692. The implant, in accordance with this patent specification, consists of a biological material that can be resorbed, and is intended to replace, completely or partially, a tendon, a ligament, a cruciate ligament. The implant has an elongated configuration and is flexible. Its main characteristic is that the structure has grooves or longitudinal ducts, intended to serve as initial growth guides for the new fibrous tissue. Also, a large number of biological materials that can be resorbed are also known and used for other types of implants.

Technical Problem In certain cases, synthetic, non-degradable implant materials have proven to have inadequate tissue affinity and, in most cases, inadequate elasticity with drag or fatigue failure, as a consequence. The biological tissue of the patient's own tendon or of deceased humans has not proven to be an optimal alternative form. The absence of a natural resource for blood supply results in the elasticity and resistance being reduced after a few weeks. Also, there is always the risk of transmitting infections when other human and animal implants are used. In cases where tissue is taken from other parts of the body, the patient may suffer, temporarily or permanently, from damage from the wound created at the site where healthy tissue has been taken.

Solution Therefore, it has been a requirement, for a long time, to produce an implant that can be resorbed, without the aforementioned drawbacks and, according to the following invention, a biocompatible, bio-degradable, porous implant in humans or animals, for the implantation therein, which comprises flexible elements of thread type, has been produced consequently, which is characterized in that the elements in the form of thread consist of a number of bundles of threads containing up to several thousand threads, which , in turn, contain 50 to 500 filaments, with a combined density of 5 to 120 tex, the yarn bundles have a twist of 0 to 150 revolutions / meter, and are held together by weft yarns, with a density of distribution of a few threads per centimeter to approximately 100 threads per centimeter, calculated in the longitudinal direction of the thread-like element. According to the invention, it is suitable for the weft yarns to consist of the same type of yarn as the other yarns in the yarn-like element. According to the invention, the material in the yarns should consist of a linear block polymer, with a molecular weight of at least 104 Dalton, preferably at least 105 Dalton, comprising urea groups and urethane groups, and also groups of ester, at such a distance from one another that, after hydrolysis thereof, fragments arise which are so small that they can be excreted from the human body, and also comprise primary end groups of NH2 and / or OH end groups, which can be replaced, for example, by monoamines, such as butylamine or ethylamine. The implant, according to the invention, preferably consists of a central isotropic part, to absorb essentially a constant load, and a movable external part, to absorb the forces caused by extension and / or compression. According to the invention, the implant consists of an articular ligament implant or a tendon implant.

Description of Fiqura The invention will be described in greater detail in the following, with reference to the appended figure, which shows in perspective how an embodiment of the implant according to the present invention is seen.

Detailed Description The figure shows a section of an articular ligament, according to the present invention, comprising only three bundles 1 of wires. The joint ligament usually consists, for example, of 1 to 500 such bundles of threads, depending on which part of the body is to be used. As can be seen from the figure, these bundles 1 of threads are twisted slightly, with a twist of 10 to 150 revolutions per meter. This twisting is primarily intended to prevent entanglement of the filaments and / or yarns across the width of the ligament. The bundles 1 of yarns consist of up to several thousand yarns 2, which, in turn, each contain 50 to 500 filaments. Each bundle of yarns can thus contain a very large number of filaments, from a few hundred to several hundred thousand. In order that the bundles 1 of yarns are held together, they are joined together by weft yarns 3, which are preferably applied in a weaving machine and which uses a simpler type of fabric possible, generally a flat weave. The distance between the weft yarns can vary from a distribution density of a few yarns per cm, to about 100 yarns per cm, depending on the desired firmness of the weave. The closer the threads are, the more rigid and firm the ligament will be. The weft threads 3 suitably consist of the same material as the threads 2 in the bundles 1 of threads. The bundles 2 of wires do not have to be of the same thickness through the filament. If the implant is to be used as a joint ligament for a knee, it is appropriate that the bundles of threads in the central part of the ligament become somewhat thicker than the outer parts, so that the loads through the ligament are very similar to the autologous ligament where possible, that is to say with a central isotropic part that is essentially to absorb the constant load, while the bundles of external threads can be more easily mobile, so that they are able to freely absorb the forces caused by the extension and / or compression that arise, for example, during bending and twisting of a roller joint. The bundles of threads can, therefore, slip something in mutual relation. The construction, according to the invention, is loose, which provides an increased possibility of migration of connective tissue cells within the ligament. The strength and elasticity of the construction can be adapted, which makes it possible for a patient to be soon active after an operation, the development of the correct type of collagen fibers being thus stimulated. The adaptation is effected by varying the number of yarn bundles, the number of yarns in these yarn bundles and the density of the weft yarns. The strength in an articular ligament, according to the present invention, can vary between 50 MPa and 500 MPa. The modulus of elasticity in an articular ligament, according to the present invention, can vary between 100 MPa and 1500 MPa.

The construction, according to the present invention, provides a number of advantages, in comparison with the previously known implants, ie the maximum utilization of the yarn strength as a result of a small angle of the filament in the fiber cord (factor small cosine f), and adapted mobility, but limited, between the strands of fibers, a loose construction to increase the possibility of immigration of connective tissue cells of the body, and the adapted resistance and elasticity. The material in the filaments and the threads must be degradable in the body and preferably consist of those linear block polymers, which comprise groups of ureas and urethane groups, which include hydrolyzable ester groups and are described in the Swedish patent specification 505703 Other materials that are degradable and that can be resorbed in the body can also be used. The invention is not limited to the above-described embodiment, and can be modified in various ways within the scope of the patent claims.

Claims (5)

1. CLAIMS 1. A biocompatible, biodegradable, porous implant, in humans or animals, for implantation therein, comprising flexible elements in the form of a thread, characterized in that the elements in the form of a thread consist of a number of bundles of threads, containing up to several thousand threads, which, in turn, contain 50 to 500 filaments, with a combined density of 5 to 120 tex, the yarn bundles have a twist of 0 to 150 revolutions per meter and are kept together by weft yarns, with a distribution density of a few yarns per centimeter up to about 100 yarns per centimeter, calculated in the longitudinal direction of the yarn-like element.
2. 2. The implant, according to claim 1, characterized in that the weft yarns consist of the same type of yarn as the other yarns in the yarn-like element.
3. 3. Implant, according to any of claims 1 and 2, characterized in that the material in the yarns consists of linear block polymers, with a molecular weight of at least 104 Dalton, preferably at least 105 Dalton, comprising urea groups and groups of urethane and also ester groups, at such a distance from each other that, after hydrolysis thereof, fragments arise that are so small that they can be excreted from a human body, and also comprise primary end groups of NH2 and / or OH end groups, which can be replaced by butylamine or ethylamine.
4. 4. Implant, according to any of claims 1 to 3, characterized in that this implant consists of a central isotropic part, to absorb essentially constant loads, and a more mobile external part, to absorb the forces caused by extension and / or compression.
5. 5. Implant, according to any of claims 1 to 4, characterized in that it consists of a joint ligament implant or a tendon implant.