MX2008008109A - Surgical repair product comprising uhmwpe filaments - Google Patents

Abstract

The invention relates to an elongate surgical repair product such as a suture comprising a cable of which bending stiffness can be lowered, which fibrous member is a heat-set cable comprising at least 50 mass%of high-performance polyethylene yarn. The product shows very high tenacity, combined with a relatively high initial bending stiffness that is significantly reduced upon bending or flexing the member, without significant dimensional change;and allows both easy and well-controlled handling and good knot tying characteristics. The invention also relates to a method of making said elongate product, wherein UHMWPE filaments are subjected to heat treatment (pref . 140-151Grad C) under elongational tension.

Description

"SURGICAL REPAIR PRODUCT THAT COMPRISES UHMWPE ELEMENTS" FIELD OF THE INVENTION The invention relates to an elongated surgical repair product comprising a cable whose flexural rigidity may decrease. The invention also relates to a method for making the surgical repair product and the cable.

BACKGROUND OF THE INVENTION Such a surgical repair product is known from US Pat. No. 4,510,934. It is understood that an elongate surgical repair product is an article for use, for example, as a surgical suture to approximate soft tissue, or as a cable, ribbon, cord or band to fix or hold parts of the body such as bones, or as ligaments or artificial tendons. Elongated means that the product has a much longer length in its dimensions in the transverse direction (width, thickness). The repair product comprises at least one elongate fibrous member that typically functions as a load bearing component, which member contains filaments comprising biocompatible fibers. The repair product may comprise in addition, for example, a bone anchor, a needle, a coating material, and so on. The filaments are the structural elements that form the member, and may contain one or more monofilaments and / or multifilament yarns. A multifilament yarn is a pack of a plurality of continuous filaments, which could have been given a certain level of twisting to give the yarn some coherence. Elongated surgical repair products of the suture type have been developed over the years from a variety of materials to form the filaments, including linen, hair, cotton, silk, animal guts, and synthetic materials such as polyesters, polyamides , and polyolefins such as polyethylene or polypropylene. The material used can be absorbable or non-absorbable. Nonabsorbable products do not dissolve or degrade due to the natural action of the body after implantation. Relevant properties of the material for use in sutures and other repair products include tensile strength, flexibility, elasticity, wettability, and other surface properties. A relatively new material to produce a non-absorbable surgical repair product is multifilament yarn made from ultra-high molar mass polyethylene (UHMWPE). ultra-high molar mass polyethylene). The main advantages of this material include its biocompatibility, its good resistance to abrasion, its flexibility, and especially its very high tensile strength. High performance (or high strength) polyethylene (HPPE) yarn is here understood as a multifilament polyethylene yarn having a tensile strength greater than 2.0 N / tex. Such spinning is defined as biocompatible if it meets the relevant requirements of the FDA, for example, with reference to other components that are present in addition to the UHMWPE polymer (such as processing additives, waste after centrifugation, solvent waste, and the like. ). Elongated surgical repair products of the suture type generally contain an interlaced structure made from a multifilament yarn as a fibrous material. Such an interlaced structure provides a combination of good strength properties (of course, dependent on the type of filaments contained therein) and a high flexural flexibility, allowing easy clamping and knotting to secure the product. One disadvantage of its high flexibility, or low stiffness to bending or bending, is that the product is more difficult to handle by a surgeon, for example, by inserting something through the eye of a surgical needle or by inserting it into a wound, such as sutures based on animal or monofilament casings. This problem was also addressed in the patent US 4510934. The surgical product described therein is designated as rigid during a sewing operation, but is flexible and easy to knot during the process or tying: the elongated surgical repair product comprises a fibrous material of flexural stiffness which it can decrease during a surgical operation, whose member consists of a nucleus of monofilaments and an interlaced flexible covering that surrounds the nucleus; the core acting as a liner reinforcer, and the core and liner being separately held together. The member consisting of such a coating core combination is initially used by the surgeon to thread (through the eye of a needle and / or through the tissue of a patient), and once in the desired location the monofilament core is separates and removes from the interlaced lining, such that the tying and fastening of a knot will be made only with the flexible interlaced part (which has less flexural rigidity than the initial member containing the monofilament core).

A disadvantage of the surgical repair product known from US Pat. No. 4,510,934 is that the core has to be removed during the surgical procedure in a further and cumbersome handling step. Such extraction subsequently results in a product of smaller dimensions; or as it is said in another way, a thicker surgical repair product than what is necessary in the surgical procedure has to be used, which causes greater damage to the tissue and similar to what is really necessary. In addition, the handling properties change dramatically after core extraction; including, for example, lengthening the remaining interlaced part. Consequently, there is a need for a surgical repair product such as a suture, which has excellent strength properties, and characteristics of resistance to bending that allow for easy handling and good control during threading or suture operations, as well as effective training and restraint to make the suture knots, but without presenting such disadvantages.

BRIEF DESCRIPTION OF THE INVENTION Therefore, the object of the invention is to provide an elongated surgical repair product. high strength, and whose flexural rigidity can be reduced without having to extract a component of the product, or significantly alter its dimensions. This object is achieved according to the invention with an elongate surgical repair product in which the fibrous member is a thermosetting cable comprising at least 50% by mass of a high performance polyethylene yarn.

DETAILED DESCRIPTION OF THE INVENTION The elongated surgical repair product according to the invention has a very high tenacity, combined with a relatively high initial bending stiffness which is significantly reduced after bending or simply flexing the limb, without having to extract a component or make significant dimensional changes; consequently permitting easy and well controlled handling and good node tying characteristics. The product according to the invention can be handled by a surgeon who uses his existing auxiliary instruments, designed for relatively rigid repair products. Such properties are especially advantageous in minimal invasive surgical procedures. An additional advantage of the product according to the invention is that also after of the implant in a patient's body, the product becomes more flexible as a result of movements and causes less irritation. A further advantage is that the fibrous member exhibits less stress relaxation under stressed conditions, for example, requires fewer adjustments after its application, and allows a long-term constant fixation of bone portions by an orthopedic cable (such as for example, in the sternotomic repair or in the fixation of bone fractures). In addition, the fibrous material has a smooth surface without protruding filaments, and a low surface area related to its volume, for example, which decreases the risk of infections caused by microorganisms trapped in the limb. An elongate surgical repair product in which the fibrous member is a cable comprising a high performance polyethylene yarn may be known from other publications, such as EP 0561108 A2, EP 12933218 Al and EP 1543782 Al, but these publications do not he says nothing about the product having a greater flexural stiffness resulting from a heat treatment, and much less that such flexural stiffness can be reduced again after bending or bending. In EP 1543782 Al, a suture containing 38% by mass of an HPPE yarn and 62% by mass of a bioabsorbable polydioxanone yarn, whose suture has expanded to 90 ° C. It is said that this suture has a better flexural stiffness, that is, less than a commercial suture made from HPPE and PET yarns. The invention relates to an elongate surgical repair product comprising a fibrous member containing a high performance polyethylene (HPPE) yarn. It is understood that the HPPE yarn is a multifilament yarn of a plurality of ultra high molecular weight polyethylene filaments, which can be made from the UHMWPE polymer by a process generally referred to as gel spinning. Ultra high molecular weight (UHMWPE) polyethylene gel spinning is known to those skilled in the art; and is described in various publications, including EP 0205960 A, EP 0213208 Al, US 4413110, GB 2042414 A, EP 0200547 Bl, EP 0472114 Bl, WO 01/73173 Al, and Advanced Fiber Spinning Technology, Ed. T. Nakajima, Woodhead Publ. Ltd. (1994), ISBN 1-855-73182-7, and references cited therein. Gel spinning refers to including at least the steps of spinning at least one filament derived from a solution of ultra high molecular weight polyethylene in a spinning solvent; cooling the obtained filament to form a gel filament; extract at least partially the spinning solvent of the gel element; and stretching the filament at least in a drawing step before, during or after the extraction of the spinning solvent. Suitable spun solvents include, for example, fines, mineral oil, kerosene or decalin. The spinning solvent can be removed by evaporation, by extraction, or by a combination of evaporation and extraction routes. Such HPPE yarns are commercially available as Spectra or Dyneema® grades. The HPPE yarn of a plurality of polyethylene filaments of ultra-high molar mass indicates that in addition to the filaments there may be small amounts, for example, at most 5% by mass, of other components present as coating or sizing. Preferably, the HPPE yarn contains at most 1% other biocompatible components. Within the context of the present application, UHMWPE refers to polyethylene with an intrinsic viscosity (IV, determined according to the method PTC-179 (Hercules Inc. Rev. April 29, 1982) at 135 ° C in decalin, with a dissolution time of 16 hours, with a DBPC antioxidant in an amount of 2 gl / solution, and the viscosity in different concentrations extrapolated to zero concentration) higher than 5 dl / g. Particularly, the UHMWPE is suitable with an IV between about 8 and 40 dl / g, more preferably between 10 and 30, or 12 and 28, or between 15 and 25 dl / g. These ranges represent an optimum in the processing capacity of the polymer and in the properties of the filaments. The intrinsic viscosity is a measurement for the molar mass (also called molecular weight) that can be determined more easily than the current parameters of molar mass such as Mn and Mw. There are several empirical relationships between IV and Mw, but such a relationship is highly dependent on the distribution of molar mass. Based on the equation Mw = 5.37 * 104 [IV] 1-37 (see EP 0504954 Al) an IV of 8 dl / g would be equivalent to an Mw of about 930 kg / mol. Preferably, the UHMWPE is a linear polyethylene with less than one branch or side chain per 100 atoms, and preferably with less than one side chain per 300 carbon atoms, generally containing at least 10 carbon atoms. The linear polyethylene may also contain up to 5 mol% of one or more comonomers, such as propylene type alkenes, butene, pentene, 4-methylpentene or octene. In a preferred embodiment, the UHMWPE contains a small amount of relatively small groups as side chains, preferably a C1-C4 alkyl group. It was found that a filament derived from the UHMWPE with a certain amount of such groups shows a behavior of reduced plastic elongation. However, too large a side chain or a very high amount of side chains negatively affects the processing and especially the stretching behavior of the filaments. For this reason, UHMWPE preferably contains methyl or ethyl side chains, more preferably methyl side chains. Therefore, the UHMWPE preferably contains at least 0.2, 0.3, 0.4 or 0.5 methyl or ethyl side chains. The amount of side chains is preferably at most, most preferably at most 10 per 100 carbon atoms. The UHMWPE may be an individual polymer grade, but also a mixture of two or more different grades, for example, which differs in the IV or molar mass distribution, and / or the number of side chains. The UHMWPE filaments may also contain customary amounts, generally less than 5% by mass of conventional additives, such as anti-oxidants, thermal stabilizers, dye, nucleating agents, flow improvers, catalyst residues, etc .; as long as these components are suitable for use in a surgical product. Preferably, the UHMWPE filaments contain less than 800 ppm of residual amounts of spinning solvent, more preferably less than 500, 250, or even less than 100 ppm. The filaments may also contain other polymers, preferably polyolefin polymers, such as other polyethylenes, polypropylenes, or their copolymers, including elastic copolymers such as EPDM, EPR, etc. The amount of such other polymers is always less than the amount of UHMWPE in the filament, and preferably does not exceed 30% by mass, or more preferably is not greater than 20, 10 or 5% by mass of the UHMWPE filament. The elongate surgical repair product according to the invention comprises a cable comprising a high performance polyethylene yarn, the cable of which can assume various constructions, generally formed by a plurality of filaments. Suitable examples include woven structures, fabrics, various interlaced constructions, or combinations thereof. Preferably, the cable has an interlaced construction comprising at least 3 filaments, which combines strength and flexibility. In fact, an interlaced cable is the construction generally used to make such surgical repair products. Suitable interlaced cables include tubular or circular interlacing (hollow or solid), spiroidal interlacing, or flat interlacing if an oblique cross section is preferred instead of a round member.

It is also possible to apply a so-called entanglement of core lining (sometimes referred to as a core mantle), or a construction of entanglement over entanglement as a cable, especially for heavier cables of larger diameter. In an entanglement of core liner there is a core formed mainly of parallel filaments or of braided yarns surrounded by an interlocked coating or lining, while an interlacing over entanglement has an entangled core and an interlaced lining. The cable may contain a plurality of filaments of various constructions. Suitable examples of a filament include parallel filaments or a single yarn of multifilaments, two or more braided (or assembled) filaments, but also woven or interlaced constructions, or combinations thereof. Preferably, the filament is an individual yarn, or two or more yarns braided together. The cable, in addition to the filaments, also comprises other components, for example, compounds that provide some functional effect, such as antimicrobial or anti-inflammatory action, or which further improves the knotting performance. The amount of such other components is generally limited to 20% by mass at most (in relation to the total mass of the cable), preferably 10 at most, or 5% by mass at most. The elongate surgical repair product according to the invention comprises a cable comprising at least 50% by mass of high performance polyethylene yarn. HPPE yarns are components that contribute most of the strength properties of the cable (or fibrous material), which is the load bearing component of the product according to the invention. In addition, HPPE yarns provide the flexural rigidity behavior of the thermosetting cable. For this reason, the cable preferably comprises at least 60% by mass of HPPE yarn (relative to the total mass of the cable); more preferably at least 70, 80 or at least 90% by mass. The cable may further comprise other fibrous materials, for example, other biocompatible polymer-like materials, in order to provide some other additional properties to the member, including improved knot slip behavior or visual contrast. Here, fibrous material refers to fibers with a relatively low diameter, preferably with a size less than 20 dfex; such as a multifilament yarn or a yarn based on artificial fibers. Such other fibers they are generally present in the form of one or more filaments in the cable. The cable may contain at least 25% by mass of another fibrous material, preferably at least 20, 15, or 5% by mass, in order to achieve a certain combination of properties. If the cable is an entanglement of core liner or a construction of entanglement over entanglement, the amount of HPPE fibers in the core and liner may be the same, but also different. A high HPPE content of the core is advantageous for a high tenacity of the cable, while a high HPPE content in the coating results in a thermosetting cable with a relatively high initial bending stiffness, which can decrease substantially after the flexion. In a special embodiment, the surgical repair product according to the invention comprises an entangled cable of core coating structure, wherein the core consists substantially of HPPE yarns for excellent strength performance, and the coating contains a yarn of HPPE in combination with a polyester yarn. In another preferred embodiment, the product according to the invention comprises an interlaced cable of core coating structure, where the coating consists of substantially in HPPE yarns. Suitable examples of other fibrous materials include artificial filaments or fibers made from nonabsorbable polymers such as other polyolefins, fluoropolymers, or semiaromatic polyesters such as polyethylene terephthalate, absorbable polymers such as aliphatic polyesters based, for example, on lactides, but also small metal fibers or particles for X-ray visibility. The HPPE yarn in the product according to the invention has a tenacity of at least 2.0 N / tex; preferably its tenacity is at least 2.5, 2.8, or even at least 3.1 N / tex for excellent product strength properties. The maximum strength of UHMWPE fibers, as predicted by different theories, is not yet achieved by available yarns; in practice, the upper limit for tenacity may currently be in the order of 5 or 6 N / tex. The elongate surgical repair product cable according to the invention may contain standards having a concentration (or linear density) that can vary widely, for example, from 5 to 3000 dtex. To make thicker or heavier limbs, preferably more filaments are used, instead of thicker filaments, in order to improve the flexibility of construction control. Preferably, the filament in the member according to the invention has a concentration of at least 15 dtex, more preferably at least 25, 50, 100, 200, or at least 300 dtex. Preferably, the filament concentration is about 2750, 2500, 2250, 2000, 1800 dtex at most or even 1600 dtex at most to result in a more flexible member. The yarn in the filament preferably has a concentration range as indicated above if the filament contains only one yarn; the preferred concentration ranges for other cases can be calculated analogously. The size of the member (wire) in the producer according to the invention can be found in the complete USP range for sutures (eg, 12/0 to 10), but is not limited thereto. For the application, as for example, of orthopedic cables, artificial tendons or ligament, a member may have a cross section (round) of up to about 5 mm. Stated otherwise, suitable members may have a linear density or concentration that varies over a wide range, for example, from 2 to 20,000 tex, preferably about 20-30000 tex. The elongated product of surgical repair of According to the invention, it comprises a thermosetting cable whose flexural rigidity may decrease. In the context of the present invention, a thermosetting cable refers to a cable comprising at least 50% by mass of high performance polyethylene yarn consisting substantially of a plurality of UHMWPE filaments, which cable has been subjected to a heat treatment at elevated temperature, but below the melting point of the UHMWPE filaments under applied conditions, simultaneously maintaining the cable (and consequently its filaments) under tension of elongation, for a certain period of time, in such a way that the filaments in the cables, they are grouped together to their surface enough to increase the rigidity of the cable, but in such a way that after flexing the cable, at least part of the filaments is separated to reduce the rigidity of the cable. The temperature range for the thermosetting process is preferably between 140 and 151 ° C, more preferably between 145 and 149 ° C. Above 145 ° C, a fast and economical process is possible to group the filaments together. Below 149 ° C there is no opportunity or just a low probability that the filaments are fused together, so that they do not re-separate when flexing the cable. The tension of Applied elongation can induce the optimization of the cable structure by lightly reconfiguring the wires and filaments in the cable in such a way that they all tense (more evenly), resulting in a certain elongation of the cable. This better stress distribution results in a higher efficiency of the resistance, - that is, more filaments contribute to the resistance of the cable. In addition, the elongation stress can, in combination with the elevated temperature, also result in expansion or stretching of the UHMWPE filaments. It is known that post-expansion of the filaments generally results in an improvement of their tensile strength. Preferably, the cable was hardened in a gaseous medium, for example, in air or in a non-oxidizing atmosphere of the nitrogen gas type. It was found that a cable that had been thermosetting in a gaseous medium instead of a liquid medium, for example, superheated water, shows a higher stiffness which can decrease more effectively again after bending the cable. An additional advantage of the thermosetting in a gaseous medium is that the thermosetting medium need not be removed from the cable in a subsequent step. The adequate exposure times during the thermosetting process are of the order of several minutes, for example, 2-10 minutes; at a higher thermosetting temperature generally allows shorter exposure times. Preferably, such an elongation tension was applied, so that the cable is stretched at a stretch ratio (wire length ratio before and after heat curing) of from 1.05 to 3.0, more preferably 1.1-2.5, or even 1.2-2.0 . The advantage of a higher temperature is that the flexural stiffness increased more effectively, or in a shorter period of time. Applying a higher drawing ratio results in greater toughness, but this effect seems to be leveled at a draw ratio greater than about 2. The flexural stiffness of the wire also seems to be leveled for stretched products with a ratio greater than about 2 with base on an absolute scale (the free length of the cable that shows a specific section); but in relation to its dimensions (concentration), it is discovered that the flexural stiffness increases with a stretched ratio applied. The elongate surgical repair product according to the invention comprises a thermosetting cable having a flexural rigidity which may decrease, which means that its flexural rigidity decreases locally after flexing the cable at least once at an angle of at least 90 °, preferably with a radius less than 5 mm, preferably below 1 mm (less stiffness specifically at the point of flexion). Preferably, the cable is bent up and down (flexes) several times. Bending the cable at a greater angle, for example, up to 180 °, is more effective in reducing rigidity. After repeated bends, the tensile strength generally approximates the level of a cable (of similar construction and thickness or concentration) that is not thermosettable. The thermosetting cable shows such tensile stiffness that a certain minimum length of cable, without being supported, will not bend due to its own weight; which results in much easier and more controlled handling of the cable during the surgical operation. Bending the cable, for example, after making a first knot for the clamping will reduce the resistance, so that the placement of subsequent knots is facilitated. The elongate surgical repair product according to the invention comprises a thermosetting cable having a flexural rigidity which may decrease, with a ratio of initial flexural rigidity to decreased flexural stiffness in the range of about 2 to 15; in which the flexural stiffness is determined as the length of the cable protruding freely from a vertical tube until the cable is bent under the horizontal plane of the edge of the vertical tube. Preferably, such stiffness ratio is in the range of 2-10, more preferably 3-10. The invention further relates to a method for making an elongate surgical repair product according to the invention, comprising the steps for assembling a plurality of filaments comprising an HPPE yarn consisting substantially of a plurality of UHMWPE filaments and optionally filaments comprising other fibrous materials to form a cable, and thermosetting the cable by subjecting it to a heat treatment at elevated temperatures but below the melting point of the UHMWPE filaments under the applied conditions, simultaneously maintaining the cable under tension of elongation, preferably between 140 and 151 ° C, more preferably between 145 and 149 ° C. Suitable methods for assembling a plurality of filaments include twisting, knotting, weaving and interlacing techniques. The number of filaments in the member is not specifically limited, but the number of filaments (or yarns) to make a member is 2, typically 3 or more. To make a heavier limb, a higher number of filaments (or yarns) of some concentration is preferably applied, instead of using the same number of filaments but increasing your concentration; consequently, the member thus elaborated shows a greater decrease in stiffness after bending. Preferably, the assembly step in the method according to the invention relates to interlocking in a cable the plurality of filaments comprising the HPPE yarns. The heat-hardening step of the cable is preferably carried out in a gaseous medium, for example, in air or in a non-oxidizing atmosphere such as nitrogen gas to result in a temporary increase in stiffness. It was discovered that performing the thermosetting in a liquid medium, eg, superheated water, results in a greater rigidity, which can not effectively decrease again by simply bending the cable. The elongation stress that is applied during the thermosetting process is preferably maintained at a constant level, in order to produce a product with consistent properties. The applied tension can be adjusted to result in some stretching of the cable. Care should be taken not to overstress the cable or its filaments, and to avoid breaking the cable. The preferred conditions for the step of thermosetting in the method according to the invention, such as temperature, time, tension of applied or stretched elongation, and for the structure and composition of yarns, yarns and filaments are analogous to those described above. The thermosetting can be done in a single step, but also in multiple steps, for example, with the increase of temperature in each step, or applying a greater tension of elongation. In the method according to the invention care must be taken to handle the cable after the heat setting step so that its flexural rigidity is not prematurely reduced; that is, bending and bending should be omitted where possible. The elongated surgical repair product, for example, is preferably packaged in the elongated state; or after winding rolls (parallel) of relatively large diameter. The process according to the invention may further comprise one or more additional steps, including steps such as coating the cable, attaching a needle or bone anchor, packaging and sterilization. Such steps are known to those skilled in the art. Furthermore, the invention relates to the use of a thermosetting cable comprising at least 50% by mass of HPPE yarn consisting substantially of a plurality of polyethylene filaments of ultra-high molar mass to produce a surgical repair product. It has surprisingly been discovered that such a cable shows a tensile strength which is markedly reduced after bending the cable; which makes it very suitable for use as a cable or surgical suture (resistance to facilitate initial management by the surgeon, flexibility to allow the cable to be held and to avoid irritation of body tissue). The invention further relates to a device for a surgical method, comprising a sterile surgical repair product comprising a fibrous member whose flexural rigidity may decrease according to the invention. In addition, the equipment may comprise, for example, auxiliary surgical tools, and / or supplementary instructions for its use. The invention further relates to a surgical method, comprising the steps for approaching at least two tissue or bone portions, or attaching tissue portions of implants, with an elongate surgical repair product comprising a fibrous member whose stiffness to the bending may decrease according to the invention, and bend the member at least once to reduce its rigidity. The invention will be further elucidated with reference to the following non-limiting examples.

Comparative Experiment A 8 strands of an HPPE multifilament yarn of 226 dtex were interlaced with a tenacity of 3. 8 N / tex and modulus of tensile elasticity of 130 N / tex, in a Herzog interlacing machine on a cable with approximately 5.9 passes per centimeter. The interlacing properties were determined by applying the following methods: • Fractional properties. tensile strength (or tenacity), modulus of elasticity to the traction (or modulus) and elongation of rupture (or eab - elongation at break) are defined and determined with a procedure in agreement with the norm ASTM D 885M, using a meter Nominal length of the 500 nm fiber, a cross head speed of 50% / min., And Instrom 2714 clamps, type Fiber Grip D5618C for multifilament yarns. The strength of the interlocking members was measured on a Zwick 1435 apparatus with Instron 1497K clamps. Based on the stress and strain curve, the modulus of tensile elasticity is determined as the gradient between a voltage of 0.3 and 1%. For the calculation of the modulus of elasticity to the traction, the measured tensile elasticity forces are divided by the concentration, determined to the 10 meters of yarn or 1 meter of cable. • The flexural stiffness of a cable was determined by slowly entering the cable into the lower opening of a vertically placed tube 150 nm long and of an adequate diameter (4 mm in this case) until the cable protruded from the bent upper opening by its own weight and the end of the cable passed under the horizontal plane of the upper opening of the tube (the cable is supported by the edge of the tube). The experiments were performed before and after flexing the cable along its entire length by moving it 10 times on a stainless steel rod 1 mm in diameter at a 90 ° angle, being simultaneously tensioned with a mass of 1.5 kg. Stiffness is expressed as the length of the cable extended from the tube (average of 5 experiments); • The stress relaxation was measured in a cable, by tensioning the cable in a tensile tester with 1 or 1.5 N / tex, and measuring the residual stresses after 5 and 10 minutes; the values reported are expressed as the initial tension% (average of 2 experiments).

Examples 1-3 An interlaced cable was made as described in Comparative Example A, and subsequently thermosetting by introducing it into one end of a hot air oven at a constant temperature of 140 ° C, with a feed rate of 2 ml / min (controlled by feed rolls). The wire path in the furnace was 8.4 meters, and the winding speed after leaving the furnace at the other end varied to result in draw ratios of 1.11, 1.28 and 1.43, respectively. The properties were determined as indicated above; the results are shown in Table 1.

Examples 4-7 Examples 1-3 were repeated, the furnace temperature being now 151 ° C. Stretching ratios of 1.13, 1.34, 1.55 and 2.33, respectively, were applied. The results are also listed in Table 1. It can be seen that the flexural stiffness increases with the thermosetting temperature and the stretched ratio applied. The thermosetting cable shows an initial stiffness that can be approximately 2-5 times after bending the cable several times, and then at a level similar to that of a thermosetting cable (normalized to the concentration of the cable). The thermosetting cable also shows a higher level of tension residual in relaxation tests, fifteen

Claims (9)

1. NOVELTY OF THE INVENTION Having described the invention as antecedent, the content of the following claims is claimed as property REI IDNICATIONS 1. An elongate surgical repair product comprising a cable whose flexural rigidity decreases, characterized in that the fibrous member is a thermosetting cable comprising at least 50% by mass of high performance polyethylene yarn.
2. 2. The surgical repair product according to claim 1, characterized in that the high performance polyethylene yarn has a tenacity of at least 2.0 N / tex.
3. 3. The surgical repair product according to claim 1 or 2, characterized in that the cable has an interlaced construction.
4. 4. The surgical repair product according to any of claims 1-3, characterized in that the filaments comprise at least 60% by mass of the high performance polyethylene yarn.
5. 5. The surgical repair product according to claims 1-4, characterized in that the cable has a linear density of about 20-3000 tex.
6. 6. A method for making an elongate surgical repair product according to any of claims 1-5, characterized in that it comprises the steps for assembling a plurality of filaments comprising high performance polyethylene yarn which substantially consists of a plurality of UHMWPE filaments and optionally filaments comprising other fibrous materials to form a cable, which cable has been subjected to a heat treatment at elevated temperature, but which is below the melting point of the UHMWPE filaments under the applied conditions, while maintaining the cable (and consequently to its filaments) under tension of elongation, during a certain period of time, in such a way that the filaments in the cable are grouped together in their surface enough to increase the rigidity of the cable, but in such a way that after the bending of the cable at least part of the elements are separated to decrease the rigidity of the cable.
7. The method according to claim 6, characterized in that the thermosetting is carried out at a temperature between 140 and 151 ° C.
8. The method according to claim 6, characterized in that the thermosetting is carried out at a temperature between 145 and 149 ° C.
9. 9. A device for a surgical method, characterized in that it comprises an elongate product of surgical repair comprising a cable whose flexural rigidity can decrease according to any of claims 1-5.