Non-absorptive surgical suture for soft tissue suture and preparation method of non-absorptive surgical suture

Abstract

The invention relates to a non-absorptive surgical suture which is provided with one or more barbs at intervals, the barbs are slightly and uniformly distributed on the surface of the suture in a three-dimensional mode, no barbs are arranged in the middle of the suture, and the suture can be connected with a double-needle or single-needle suture needle. The preparation method of the suture comprises the following steps: extruding a medical suture material selected from polypropylene or polyamide through a twin-screw extruder, and slicing to obtain a spinning raw material; the spinning raw materials are dried until the water content is smaller than 0.005 wt%, the dried spinning raw materials are added into a spinning machine for spinning, and filaments are cooled to obtain nascent fibers; fibers obtained by spinning are subjected to chemical crosslinking treatment, so that the physical and mechanical properties of the fibers are enhanced; and clamping the head end and the tail end of the cross-linked fiber precursor by using a clamp, and processing to obtain the barb suture. According to the high-strength barb suture, chemical cross-linking treatment and barb arrangement are conducted on a specific suture, the tensile strength of the barb suture is improved, the problem that the barb suture is prone to breakage is solved, and the high-strength barb suture can be used as a minimally invasive surgical instrument in surgical operations such as soft tissue repair operations under an arthroscope and has good application prospects.

Description

Technical Field

[0001] The present invention relates to a non - absorbable surgical suture for soft tissue suture and its preparation method, belonging to the field of medical devices, especially used as a minimally invasive surgical instrument in surgical operations, such as arthroscopic soft tissue repair. More specifically, the present invention relates to a non - absorbable knotless barbed suture with good tensile strength. The suture selects specific non - absorbable materials such as polypropylene or polyamide as the main body of the suture, optimizes the cross - linking process conditions, and cooperates with a suitable outer coating material to obtain a knotless barbed suture suitable for the tensile strength of soft tissue suture. Background Art

[0002] The non - absorbable surgical suture for soft tissue suture involved in the present invention, especially the knotless suture (barbed suture), is a special suture material widely used in the medical field. Its remarkable feature is that no traditional knotting operation is required during the entire suture process. In the 1990s, the United States and Russia publicly disclosed medical barbed sutures, which can be used for surgical sutures, plastic surgery for removing wrinkles or lifting skin tissues on the face, neck, chest, etc., and operations for removing wrinkles. This design not only simplifies the surgical process but also improves the efficiency and safety of suturing.

[0003] The design principle of the barbed suture is to form a series of barbs with a certain angle and 360° spiral distribution on the surface of the single - strand suture by using an advanced cutting process. After the suture passes through the tissue, these barbs can firmly grasp the tissue like a one - way valve, only going in and not coming out, thus ensuring the stability of the suture. This design makes the suture process more convenient, without the need for additional knotting steps, and also reduces the operation time and the frequency of using operating forceps.

[0004] Knotless sutures are mainly applied in the fields of general surgery, orthopedics, obstetrics and gynecology, etc. Among them, general surgery is the largest application field, accounting for about 24% of the market share. In general surgery, knotless sutures are widely used in occasions that require high - strength fixation and reduce the possibility of slippage, such as bile duct suture in laparoscopic hepatectomy combined surgery, laparoscopic repair of gastric and duodenal perforation, etc. These applications not only reduce the surgical difficulty, shorten the operation time, but also reduce the occurrence of complications and promote the recovery of patients.

[0005] Currently, the global knotless suture market is mainly dominated by several core manufacturers, including Johnson & Johnson and Medtronic, etc. However, domestic knotless sutures are gradually emerging, and the market share is gradually increasing. This change has promoted the technological innovation and quality improvement of products.

[0006] With the continuous development of technologies such as new materials, micro-nano technology, and 3D printing, the performance of knotless sutures has been continuously improved, and their application scope has been further broadened. For example, the design of barbed wires has evolved from unidirectional to bidirectional to better meet the needs of different surgical scenarios. At the same time, continuous exploration has been carried out on the application of bioabsorbable materials in knotless sutures to reduce the pain and infection risk of patients.

[0007] The comparison of the curative effects between non-absorbable non-traumatizing sutures and absorbable sutures in continuous intradermal suture shows that the key to the success of continuous intradermal suture with non-absorbable non-traumatizing sutures is good subcutaneous suture, which basically achieves a tension-free state between the sutured skin edges. And timely removal of the sutures after the wound heals postoperatively eliminates the foreign body irritation and inflammatory reaction of the sutures to the tissue, so it can significantly reduce the formation of scars, which is beneficial to the patient's skin beauty and avoids functional disorders.

[0008] Common medical barbed wires are monofilaments, and the cross-section of the monofilament is generally circular. The manufacturing method of medical barbed wires is to cut barbs on the circular monofilament. This method damages the integrity of the wire structure. Therefore, compared with surgical wires of the same size, its strength is significantly reduced, and the surgical wire is prone to break at the side of the barb during use, or the barb falls off. Since the barbs are formed by cutting the surface of the wire body, there are also limitations in the size and thickness of the barbs; since the tip of the barb is too sharp, it causes discomfort to the skin tissue or stimulates the nerves nearby, resulting in serious medical accidents. To minimize the damage to the tensile strength of the wire, the volume of the barb is small and relatively sharp, and the anchoring strength of the barb on organic tissue is weak, and the knotless effect is poor. In patents CN102869818A and EP2690206A1, barbed wires are made by the method of stamping model sawteeth. This method is to heat the preformed wire in the mold to a temperature below the melting point and above the glass transition temperature and form barbs by pressurization. Although the main body of the wire is not cut, due to the deformation of the preformed wire under the conditions of heating and pressurization, the original physical properties of the wire are broken, and the original tensile strength of the wire will also be damaged, which will reduce its use effect.

[0009] The knotless barbed suture, as an innovative suture material, has been widely used in the medical field. However, it also has some problems, especially the problem of easy thread breakage of the barbed suture. The reasons may be as follows: First, it is the problem of suture material. If the quality of the suture material is poor or there are problems in the production process, it may lead to insufficient suture strength and easy breakage. Second, improper suture technique. If the doctor uses improper technique during suture, such as excessive traction of the suture during suture, it may cause damage to the suture and lead to easy breakage of the suture. Third, excessive patient movement. During the wound healing period, if the patient moves excessively or the wound is under great tension, it may cause pulling on the suture and lead to suture breakage. Fourth, wound infection. If the wound becomes infected, it may corrode the suture, affect its strength, and thus lead to suture breakage. Fifth, suture aging. Over time, the suture may lose its original strength due to aging. Especially in the body environment, it may accelerate the aging process due to the influence of body fluids and lead to easy breakage of the suture. In order to reduce the situation of barbed suture thread breakage, doctors will consider the material and strength of the suture when choosing the suture, and adopt the correct technique during suture to avoid excessive traction of the suture. At the same time, patients should avoid excessive movement during the wound healing period to reduce the pulling on the suture. If the wound becomes infected, it should be treated in time to reduce the influence on the suture. Fundamentally speaking, it is still the problem of suture strength. The early barbed sutures may be damaged during the manufacturing process due to cutting and forming, affecting the tensile strength of the suture. Although the second-generation barbed sutures use an imprinting technique, the strength of the suture is still a factor that needs to be considered.

[0010] Polypropylene or polyamide sutures are preferably used as common non-absorbable suture materials because of their high strength, low relative density, water-insoluble, acid and alkali-resistant, non-degradable by body tissues, small tissue reaction, good chemical stability and biocompatibility, and the surface of polypropylene or polyamide monofilaments is smooth, and they pass through human tissues smoothly during suture. However, because of the difficulty in knotting and easy disconnection, barbs are set on them, so they are more suitable for soft tissue suture scenarios. However, the above-mentioned common problem of easy thread breakage of barbed sutures has always existed. The present invention unexpectedly found a systematic solution to this problem through a large number of experiments. Summary of the Invention

[0011] The present invention provides a non-absorbable barbed suture, comprising a filamentous structure elongate body having one or more spaced barbs projecting from the surface of the elongate body along the length direction of the elongate body. The term "filamentous" as used in the present invention is used in its broadest sense and generally refers to an elongated structure. The term "filamentous" generally also refers to and includes a structure having a first axis that is at least 2 times, at least 10 times, at least 100 times, at least 100 times, or at least 1000 times greater than a second axis perpendicular to the first inner axis, for example, its length is at least twice its diameter. In certain embodiments, the average diameter of the filamentous structure over its entire length is from 0.1 mm to 10 mm. In certain embodiments, the average diameter of the filamentous structure over its entire length is from 1 mm to 5 mm. In certain embodiments, the average diameter of the elongate body filamentous structure is less than 1 mm. In certain embodiments, the average diameter of the filamentous structure is less than 500 microns. In certain embodiments, the average diameter of the filamentous structure is less than 250 microns. In certain embodiments, the average diameter of the filamentous structure is less than 200 microns. In certain embodiments, the average diameter of the filamentous structure is from 20 microns to 5000 microns. In certain embodiments, the average diameter of the filamentous structure is from 50 microns to 400 microns. In certain embodiments, the average diameter of the filamentous structure is from 70 microns to 350 microns. In certain embodiments, the average diameter of the filamentous structure is from 100 microns to 300 microns. In certain embodiments, the average diameter of the filamentous structure is from 150 microns to 200 microns. In certain embodiments, the average diameter of the filamentous structure is 100 microns. In certain embodiments, the average diameter of the filamentous structure is 150 microns. In certain embodiments, the average diameter of the filamentous structure is 200 microns. In certain embodiments, the average diameter of the filamentous structure is from 20 microns to 150 microns. In certain embodiments, the average diameter of the filamentous structure is from 150 microns to 800 microns.

[0012] The non-absorbable barbed suture described in the present invention is generally prepared using the same materials as conventional sutures. More specifically, the non-absorbable suture can be composed of a polypropylene or polyamide suture with a sewing needle, and the sewing needle can be a double needle or a single needle. The surface of the suture has three-dimensional, uniformly distributed micro barbs. There is approximately 0.05 - 2 cm, preferably 0.075 - 1.5 cm, more preferably 0.1 - 1 cm without barbs in the center of the suture. The barbs extend in various directions, such as in an opposing shape, to both sides and are connected to the sewing needle. The connection part is 0.5 - 5 cm long, preferably 1 - 4 cm long, more preferably 2 - 3 cm long. More preferably, the barb parameters are key control points in production, including the processing length, tangent depth, tangent angle, and processing step distance. Among them, the processing length is set according to the processed suture. The tangent depth is controlled at 0.1 - 0.6 mm, preferably 0.2 - 0.5 mm, more preferably 0.3 - 0.4 mm. The tangent angle is controlled at 20 - 65 degrees, preferably 35 - 50 degrees, more preferably 40 - 45 degrees. The processing step distance is controlled at 0.5 - 3 mm, preferably 0.8 - 2 mm, more preferably 1 - 1.5 mm. Preferably, its surface has three-dimensional micro barbs that extend in an opposing shape to both sides and are connected to the sewing needle. When the suture is sutured, it enters the tissue along the direction of the barbs. As the barbs at the other end of the suture open, it embeds into the surrounding tissue. Without tying a knot, the suture can be fixed at the corresponding position.

[0013] The barbs are configured to allow the barbed suture to pass through tissue in one direction but prevent movement of the barbed suture in the opposite direction, so barbed sutures are commonly used in cosmetic, laparoscopic, and endoscopic procedures. The number of barbs required on a particular suture is affected by the size of the wound and the force required to keep the wound closed. When the wound or the tissue repair required is relatively small, it may be desirable to reduce the number of barbs. A two-way barbed suture is desirable when the barbs on part of the suture allow the suture to pass in one direction and the barbs on another part of the suture allow the suture to pass in another direction to achieve a tight suture. Various methods can be used to form barbs on the suture, such as mechanical cutting, laser cutting, injection molding, stamping, extrusion, etc. The conventional cutting methods for forming barbs need to be more achievable, more efficient, and more economical in terms of maintaining sharpness, fast movement, and separating costs, and need to be changed by varying the size, position, depth, and the number of barbs required on the suture. The tool required to form the barbed suture can be a blade or a rotary blade, and its geometry can be, for example, rectangular, square, circular, flat, star-shaped, octagonal, triangular, spatula-shaped, arrow-shaped, peg-shaped, and oval-shaped. The barbed suture can have barbs protruding towards one end on one part and the remaining barbs protruding towards the other end to form multiple barbs, so as to form two-way barbs. The angle between the formed barbs and the axial direction of the suture body is controlled at 20 - 65 degrees, preferably 35 - 50 degrees, more preferably 40 - 45 degrees, and most preferably 45 degrees. Various cross-sectional geometries of the suture before forming barbs can be circular, oval, square, star-shaped, octagonal, rectangular, and flat, etc. The arrangement of the barbs can form any suitable pattern, for example, spiral, linear, or randomly spaced, and the pattern can be symmetric or asymmetric. The number, configuration, spacing, and surface area of the barbs can be changed according to the tissue where the barbed suture is used and the composition and geometry of the material used to form the suture. In addition, the ratio of the barbs can be kept relatively stable, while the total length and spacing of the barbs can be determined by the tissue being joined. The formed barbs can include the following geometries: for example, circular, triangular, square, oblique, oval, octagonal, rectangular, and flat.

[0014] The non-degradable barbed suture constructed according to the present invention, suitable non-degradable materials for forming the barbed suture include, for example, polypropylene, polyamides (such as nylon), etc. The filaments and fibers for forming the present invention can be prepared using any techniques known to those skilled in the art, such as extrusion, molding, and / or solvent casting. As part of the suture forming process, the filaments themselves can be stretched, oriented, crimped, twisted, blended, or air-jet entangled to form yarns. When forming barbs on the medical device, it can be sterilized using any method known to those skilled in the art. The barbed suture according to the present invention can be coated or impregnated with one or more substances useful in medical surgery, which accelerate or beneficially improve the healing process when the medical device is used in a wound or surgical site. In certain embodiments, the coating layer can be formed from a degradable polymer selected from the group consisting of lactones, carbonates, polyorthoesters, hydroxyalkanoates, hydroxybutyrates, bioactive agents, polyanhydrides, siloxanes, calcium stearoyl lactate, ethylene polymers, high molecular weight paraffins and oils, natural polymers, proteins, polysaccharides, suspendable particles, dispersible particles, microspheres, nanospheres, rods, their homopolymers, their copolymers, and combinations thereof. Suitable bioactive agents include pesticides, antimicrobials, antibiotics, cell proliferation inhibitors, drugs, growth factors, anticoagulants, coagulants, analgesics, anesthetics, anti-inflammatory agents, wound repair agents, etc., chemotherapeutic agents, biologics, protein therapeutics, monoclonal or polyclonal antibodies, DNA, RNA, peptides, polysaccharides, lectins, lipids, probiotics, diagnostic agents, angiogenesis agents, anti-angiogenic drugs, polymer drugs, and combinations thereof. Bioactive agents include substances that are beneficial and tend to promote the healing process. For example, a suture with a bioactive agent can be provided, and the bioactive agent will be deposited at the suture site. The bioactive agent can be selected according to its antibacterial properties, ability to promote wound repair and / or tissue growth, or ability to indicate a particular disease such as thrombosis. The term "antimicrobial agent" as used herein includes an agent that helps the body kill or resist potentially pathogenic microorganisms by itself or by assisting the immune system. Antimicrobial agents include antibiotics, preservatives, quorum sensing blockers, antifungals, antivirals, surfactants, metal ions, antimicrobial proteins and peptides, antimicrobial polysaccharides, disinfectants, and combinations thereof. Antimicrobial agents that are slowly released into the tissue can be used in this way to help overcome clinical or subclinical infections at the surgical or traumatic wound site. In an embodiment, suitable antimicrobial agents can be dissolved in one or more solvents.The following antimicrobials can be used alone or in combination with other bioactive agents: anthracyclines, doxorubicin, mitoxantrone, fluoropyrimidines, 5-fluorouracil, folic acid antagonists, methotrexate, mitoxantrone, quorum sensing blockers, brominated or halogenated furanones, podophyllotoxin, etoposide, camptothecin, hydroxyurea, platinum complexes, cisplatin, doxycycline, metronidazole, trimethoprim-sulfamethoxazole, rifamycins such as rifampicin, fourth-generation penicillins (such as ureidopenicillins, carboxypenicillins, mezlocillin, piperacillin, carbenicillin, ticarcillin and their analogs or derivatives), first-generation cephalosporins (such as cefazolin sodium, cephalexin, cefazolin, cephapirin and cephalothin), carboxypenicillins (such as ticarcillin), second-generation cephalosporins (such as cefuroxime, cefotetan and cefoxitin), third-generation cephalosporins (such as ceftiofur, cefdinir, cefoperazone, ceftazidime, ceftriaxone and cefotaxime), polyvinylpyrrolidone, fourth-generation cephalosporins (such as cefepime), monobactams (such as aztreonam), carbapenems (such as imipenem, ertapenem (meropenem)), aminoglycosides (such as streptomycin, gentamicin, tobramycin and amikacin), members of the MLS group (such as macrolides, long-acting macrolides, lincosamides, streptogramins, erythromycin, azithromycin, clindamycin, sylvanid, clarithromycin and kanamycin sulfate), tetracyclines such as minocycline, fusidic acid, trimethoprim, metronidazole, quinolones (such as ciprofloxacin, ofloxacin, gatifloxacin, moxifloxacin, levofloxacin and trovafloxacin), DNA synthesis inhibitors (such as metronidazole), sulfonamides (such as sulfamethoxazole, trimethoprim, including cefixime, spectinomycin, tetracycline, nitrofurantoin, polymyxin B and neomycin sulfate), β-lactam inhibitors such as sulbactam, chloramphenicol, glycopeptides such as vancomycin, mupirocin, polyenes such as amphotericin B, pyrroles such as fluconazole and other antimicrobials known in the art. The barbed suture according to the invention can also include, for example, biocompatible plasticizers, antioxidants and colorants, which can be immersed in the filaments used to form the sutures of the present disclosure or included in the coating layer thereon. Bioactive agents can be applied to the barbed medical devices of the present disclosure using methods known to those skilled in the art, such as dipping, spraying, vapor deposition, brushing, solvent evaporation, mixing, etc. The barbed sutures of the present invention can be dyed to increase the visibility of the workpiece in the surgical area. Any dye suitable for introducing into a medical device can be used, and the dyeing can be carried out by adding an amount of the dye up to about a few percentages.

[0015] The suture of the present invention may include a needle at one end. To facilitate attachment of the needle to the suture, a conventional tip-containing reagent may be applied in the braiding. Sutures with tips at both ends may be desired to attach a needle to each end of the suture to provide a double-needle suture. Attachment of the needle may be performed using any conventional method such as crimping, molding, etc. In certain embodiments, the diameter of the needle is less than, equal to, or greater than the diameter of the surgical suture. In certain embodiments, the needle is selected from the group consisting of: straight needles, 1 / 4 circle needles, 3 / 8 circle needles, 1 / 2 circle needles, 5 / 8 circle needles, compound curve needles, half-curved (also known as ski-shaped) needles, and half-curved needles at the ends of a straight segment (also known as canoe-shaped) needles. Needles may also be classified according to their tip geometry; examples include: tapered needles (the needle body is round and smoothly tapers to a point); cutting needles (the needle body is triangular and has a sharp blade on the inner curve); reverse cutting needles (with a blade on the outer side); primary cutting needles; trocar tips or tapered incisions (the needle body is round and tapered, but the end is a small triangular cutting tip); blunt tips for suturing delicate tissues; side-cutting or spatula-shaped tips for ophthalmic surgery (flat on top and bottom, with the cutting edge from the front to one side). Each possibility represents a separate embodiment of the present invention. In certain embodiments, the needle is rigid enough to penetrate the skin. In certain embodiments, the needle is made of ceramic, metal, or plastic.

[0016] In certain embodiments, the surgical suture is inserted into the skin at least 0.01 mm. In certain embodiments, the surgical suture is inserted into the skin or subcutaneous layer up to 5 mm. In certain embodiments, the surgical suture is inserted into the skin or subcutaneous layer from 0.01 mm to 5 mm. In certain embodiments, the surgical suture is inserted into the skin or subcutaneous layer from 1 mm to 2 mm. In certain embodiments, the surgical suture is inserted into the epidermis. In certain embodiments, the surgical suture is inserted into the dermis. In certain embodiments, the surgical suture is inserted into the subcutaneous layer. In certain embodiments, the surgical suture is inserted beneath the epidermis. In certain embodiments, the surgical suture is inserted beneath the dermis. In certain embodiments, the surgical suture is inserted beneath the subcutaneous layer. Each possibility represents a separate embodiment of the present invention.

[0017] Barbed sutures and placement methods applicable to the present invention are well known in the art. For example, such sutures can be used to elevate tissue, which is desirable in certain cosmetic surgeries. In certain embodiments, a method of suturing tissue using a barbed suture includes inserting a first end of the suture, optionally attached to a needle, at an insertion point on the body surface. The first end of the suture can be pushed through soft tissue until the end exits the soft tissue at an exit point. The first end of the suture can then be grasped and pulled forcefully to cause a first portion of the suture to pass through the soft tissue, such that a segment of the first portion of the suture remains in the soft tissue between the insertion point and the exit point of the first end. The soft tissue can then be manually grouped and lifted along at least a portion of the suture to obtain a desired amount of elevation. The suture can be used as a minimally invasive surgical instrument in any cosmetic, plastic, open endoscopic, or laparoscopic procedure, and can also be used to attach one tissue to another, including, but not limited to, attaching tissue to a ligament. Specific applications in cosmetic surgery include, for example, facial augmentation, eyebrow augmentation, buttock augmentation, and breast augmentation. Although the above description contains many details, these details should not be construed as limiting the scope of the present disclosure, but merely as illustrations of its embodiments. Within the scope and spirit of the invention defined by the appended claims, many other possibilities can be foreseen by those skilled in the art.

[0018] The preparation method of the non-absorbable surgical suture, especially the knotless barbed suture, described in the present invention controls and enhances the tensile strength of the suture described in the present invention through the following key steps. Specifically, it includes: 1. Preparation of spinning raw materials: Appropriate medical suture materials, such as polypropylene, polyamide, etc., are extruded and sliced by a twin-screw extruder to obtain spinning raw materials; 2. Spinning: The spinning raw materials are dried to a moisture content of less than 0.005 wt%, added to a spinning machine for spinning, and the filaments are cooled to obtain nascent fibers; 3. Chemical cross-linking: The fibers obtained by spinning are subjected to chemical cross-linking treatment to enhance their physical and mechanical properties; 4. Formation of barbs: The head and tail ends of the cross-linked fiber filaments are clamped using a fixture, and the barbed suture is obtained through treatment. Further, the barbed suture undergoes thread cutting, needle threading, winding and packaging, sterilization, and sealed packaging to obtain a knotless barbed suture.

[0019] To further enhance the tensile strength of the suture according to the present invention, the following treatments can also be carried out, such as stretching: stretching the obtained nascent fibers to obtain fiber filaments; antibacterial treatment: to reduce the risk of wound infection, the suture is subjected to antibacterial treatment. Post-treatment: The suture after cross-linking and antibacterial treatment can also be subjected to post-treatment steps such as washing and drying according to needs to remove residual chemical substances and ensure the safety and biocompatibility of the suture. For the convenience of users to quickly identify and use different types of sutures, a dyeing treatment can be carried out: immersing the fiber filaments in a solution tank containing a dyeing substance and then drying to obtain the dyed fiber filaments; performance testing: The manufactured suture is subjected to physical and mechanical performance tests in accordance with the national medical industry standards, such as tensile strength, softness, etc., to ensure that it meets the requirements for medical use. Packaging and sterilization: Finally, the suture will be packaged in a sterile environment and sterilized by methods such as ethylene oxide sterilization to ensure the safety of the product during use.

[0020] According to the preparation method of the non-absorbable surgical suture, especially the knotless barbed suture, described in the present invention above, further, the spinning raw material is preferably further, an appropriate polypropylene raw material, especially polypropylene having a viscosity-average molecular weight of more than 1 million, preferably 1 million - 6 million, more preferably polypropylene with a viscosity-average molecular weight exceeding 2 million, and its molecular weight distribution is between 3.5 - 4.8, preferably 4 - 4.5. The viscosity-average molecular weight M of the polypropylene is determined as follows: The polypropylene resin sample obtained by polymerization is placed in a decalin solution at 135°C, and the intrinsic viscosity [η] of the polypropylene resin is determined according to the method of GB / T 1632.3-2010 "Plastics - Determination of viscosity of dilute polymer solutions using capillary viscometers - Part 3: Polyethylene and polypropylene". Then substitute it into the formula M = K·[η], where K = 53700 and α = 1.49, and the viscosity-average molecular weight M can be calculated. The molecular weight distribution of polypropylene is determined as follows: It is measured using a high-temperature gel permeation chromatograph, with 1,2,4-trichlorobenzene as the solvent, the solution concentration is 1.0 mg / ml, the test temperature is 150°C, and the solution flow rate is 1.0 ml / min.

[0021] Furthermore, for the preparation method of the non-absorbable surgical suture of the present invention, especially the knotless barbed suture, when spinning, the selected polymer material can be made into fibers by techniques such as melt spinning or wet spinning. The melt spinning is to heat the polymer to a molten state and then extrude it into filaments; the wet spinning is to dissolve the polymer in a solvent and extrude it into a coagulation bath to solidify into filaments. Chemical crosslinking usually uses crosslinking agents such as epoxidized soybean oil, genipin, dicumyl peroxide (DCP), divinylbenzene (DVB), etc. Among them, the weight ratio of the polypropylene to the crosslinking agent is 100:(0.01 - 6); preferably, the weight ratio of the polypropylene to the crosslinking agent is 100:(1 - 5); more preferably, the weight ratio of the polypropylene to the crosslinking agent is 100:3. These crosslinking agents can react with the active groups in the polymer molecules to form a three-dimensional network structure, thereby improving the strength and stability of the suture. For the preparation method of the non-absorbable surgical suture of the present invention, especially the knotless barbed suture, the barbed suture can be directly formed by pressing a film or obtained by cutting on its surface with a tool. For the preparation method of the non-absorbable surgical suture of the present invention, especially the knotless barbed suture, the antibacterial treatment is achieved by coating an antibacterial agent, such as a broad-spectrum antibacterial agent like triclosan, on the surface of the suture. The antibacterial agent can inhibit the growth of bacteria and reduce the infection probability. Through the above steps, these sutures can provide better wound closure effects in medical surgeries while reducing the infection risk.

[0022] The preparation method of the non-absorbable surgical suture, especially the knotless barbed suture, described in the present invention, wherein the melt spinning is to add polypropylene raw material into a co-rotating twin-screw extruder for melt extrusion. The extrusion temperature is 150°C - 190°C, and the residence time of the material in the twin-screw extruder is between 80 - 350 s. The polypropylene obtained by cooling and pelletizing the extrudate is spun into shape by a spinning machine. The temperatures of the first spinning zone, the second spinning zone, and the third spinning zone are adjusted according to the formula, and parameters such as the diameter of the spinneret of the spinning machine, the advancing speed of the feed rod, the extrusion line speed, and the winding line speed are selected or controlled. The as-spun primary fibers are stretched by a hot plate stretcher by a certain multiple to enhance the strength and toughness of the fibers. Through tension heat setting, the structure of the fibers is stabilized, and impregnation and coating are carried out as needed to improve the performance of the suture. Finally, according to the suture specifications, sutures with different lengths, different thicknesses, and different barbs are made by conventional methods in the art. Further, during the spinning process, the heating temperature of the first screw zone is 130 - 150°C, the heating temperature of the second screw zone is 135 - 145°C, the heating temperature of the third screw zone is 140 - 150°C, the heating temperature of the flange is 142 - 145°C, and the heating temperature of the casing is 143 - 149°C. Preferably, the heating temperature of the first screw zone is 138°C, the heating temperature of the second screw zone is 140°C, the heating temperature of the third screw zone is 146°C, the heating temperature of the flange is 144°C, and the heating temperature of the casing is 147°C. The diameter of the spinneret of the spinning machine is 0.6 - 1.0 mm, the advancing speed of the feed rod is 3.3 - 4.6 mm / min, the extrusion line speed is 0.5 - 0.8 m / min, and the winding line speed is 13 - 17 m / min. Preferably, the diameter of the spinneret of the spinning machine is 1 mm, the advancing speed of the feed rod is 4.3 mm / min, the extrusion line speed is 0.7 m / min, and the winding line speed is 15 m / min.

[0023] The non-absorbable surgical suture described in the present invention, especially the preparation method of the knotless barbed suture, wherein the dyeing is the dyeing bath immersion dyeing well-known in the art. In some embodiments, the specific steps of dyeing are as follows: impregnate the fiber filaments in a solution tank containing the dyeing substance at a speed of 0.2-0.6 m / min, keep the time for the fiber to pass through the solution tank for 15-33 min, and then dry the fiber filaments impregnated with the dyeing substance at 32-46 °C to obtain the dyed fiber filaments. Further, in the specific process of cutting the barbs in the preparation method, the fiber filaments rotate axially, the rotation rate of the thread is 1-5 s / circle, preferably 2-4 s / circle, more preferably 3 s / circle. The middle of the made suture has about 0.05-2 cm, preferably 0.075-1.5 cm, more preferably 0.1-1 cm without barbs. The barbs extend in various directions such as in an opposing shape to both sides and are connected to the suture needle. The connection part is 0.5-5 cm, preferably 1-4 cm, more preferably 2-3 cm long. More preferably, the barb parameters are the key control points in production including the processing length, the tangent depth, the tangent angle, and the processing step distance. Among them, the processing length is set according to the processed suture, the tangent depth is controlled at 0.1-0.6 mm, preferably 0.2-0.5 mm, more preferably 0.3-0.4 mm, the tangent angle is controlled at 20-65 degrees, preferably 35-50 degrees, more preferably 40-45 degrees, and the processing step distance is controlled at 0.5-3 mm, preferably 0.8-2 mm, more preferably 1-1.5 mm.

[0024] The present invention provides a knotless barbed suture prepared by any of the above preparation processes. Compared with the prior art, by selecting appropriate suture materials, chemical cross-linking methods within a suitable range, and a specifically optimized structure, the present invention effectively solves the problem that the knotless barbed suture is prone to thread breakage, exhibits excellent tensile properties, and is safer and more reliable for clinical use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the basic structure diagram of the knotless barbed suture.

[0026] Figure 2 It is the barb setting structure diagram of the knotless barbed suture. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Example 1

[0028] The first aspect of this embodiment provides a preparation method for a knotless barbed suture, including the following steps: Preparation of spinning raw materials: After mixing polypropylene, it is extruded at 115 °C through a twin-screw extruder and sliced to obtain spinning raw materials; Spinning: The spinning raw materials are dried to a moisture content of less than 0.005 wt% and then added to a spinning machine for spinning. The filaments are cooled with alcohol to obtain primary fibers; Drawing: The fibers are drawn to obtain fiber filaments, which are subjected to a single water bath drawing and two hot plate drawings to obtain fiber filaments; Chemical crosslinking: The fibers are chemically crosslinked to enhance their physical and mechanical properties; Dyeing: The fiber filaments are impregnated in a solution tank containing a dyeing substance at a speed of 0.3 m / min, and the time for the fibers to pass through the solution tank is maintained at 20 min. Then, the fiber filaments impregnated with the dyeing substance are dried at 40 °C to obtain dyed fiber filaments. The original USP size of the dyed fiber filaments is 3-0; Cutting barbs: The head and tail ends of the dyed fiber filaments are clamped using a fixture, and a tool is used to cut on the surface of the dyed fiber filaments to obtain barbed sutures. During the cutting process, the dyed fiber filaments rotate axially, and the rotation rate of the line is 3 s / turn. The barbed sutures are obtained through thread cutting, threading, winding and packaging, sterilization, and sealing packaging to obtain knotless barbed sutures. During the spinning process: The heating temperature of the first zone of the screw is 135 °C, the heating temperature of the second zone of the screw is 145 °C, the heating temperature of the third zone of the screw is 140 °C, the heating temperature of the flange is 145 °C, and the heating temperature of the box body is 145 °C; The diameter of the nozzle of the spinning machine is 0.8 mm, the feeding rod propulsion speed is 3.5 mm / min, the extrusion line speed is 0.6 m / min, and the winding line speed is 15 m / min; The temperature of the single water bath drawing is 40 °C, and the drawing ratio is 3 times. The temperature of the first hot plate drawing is 60 °C, and the drawing ratio is 8 times. The temperature of the second hot plate drawing is 50 °C, and the drawing ratio is 5 times; There are 8 barbs per centimeter on the barbed suture; The angle between the barb and the line body is 20°.

[0029] For the knotless barbed suture prepared in Example 1, test the tensile strength, elongation at break, etc. of the knotless barbed suture obtained in the example according to the standard method.

[0030] Examples 2-5

[0031] Examples 2-5 provide a preparation method for a knotless barbed suture. The specific implementation method is the same as that of Example 1, except that the corresponding conditions are adjusted, and it is prepared by those of ordinary skill in the art according to the method of Example 1.

[0032] The factor changes and test situations of each example are shown in Table 1.

[0033] Table 1

[0034]

[0035] The polypropylene described in Table 1 is a conventional commercially available product. High molecular weight polypropylene refers to polypropylene with a viscosity-average molecular weight exceeding 1 million, and ultra-high molecular weight polypropylene refers to polypropylene with a viscosity-average molecular weight exceeding 2 million. The results show that after treatment, the tensile strength, elongation at break, etc. of the barbed suture exhibit unexpectedly significant improvements. In particular, the high molecular weight polypropylene with a viscosity-average molecular weight exceeding 1 million shows excellent performance.

Claims

1. A non-absorbable surgical suture comprising a filamentous elongated body with one or more barbs spaced apart from each other, the barbs protruding from the surface of the barbed suture along the length of the elongated body, characterized in that The non-absorbable suture material is selected from polypropylene or polyamide.

2. According to the suture of claim 1, the barbs are three-dimensionally and evenly distributed on the surface of the suture, and there is no barb in the center of the suture for 0.05-2 cm, preferably 0.075-1.5 cm, and more preferably 0.1-1 cm, and the barbs extend in different states and are connected to the suture needle.

3. The suture according to claim 2, wherein the suture needle is a double needle or a single needle.

4. According to the suture of claims 2-3, the barbs extend to both sides of the suture in opposite directions, and the suture connected to the suture needle has a connection length of 0.5-5 cm, preferably 1-4 cm, and more preferably 2-3 cm.

5. According to any one of claims 1 to 4, the angle between the barb and the axial direction of the suture body is controlled at 20-65 degrees, preferably 35-50 degrees, and more preferably 40-45 degrees.

6. A method for preparing a non-absorbable surgical suture according to claim 1, comprising: The medical suture material selected from polypropylene or polyamide is extruded and sliced ​​through a twin-screw extruder to obtain a spinning raw material; the spinning raw material is dried to a moisture content of less than 0.005wt%, added to a spinning machine for spinning, and the filaments are cooled to obtain primary fibers; the fibers obtained by spinning are chemically cross-linked to enhance their physical and mechanical properties; the ends of the cross-linked fiber raw filaments are clamped with a clamp, and a suture with barbs is obtained after treatment.

7. The method according to claim 6, wherein the polypropylene raw material, in particular, has a viscosity average molecular weight of more than 1 million, preferably 1-6 million, and its molecular weight distribution is between 3.5-4.8, preferably between 4-4.

5.

8. The method according to claim 6 or 7, wherein the chemical crosslinking uses epoxidized soybean oil, genipin, dicumyl peroxide (DCP) or divinyl benzene (DVB) as a crosslinking agent.

9. The method according to claim 8, wherein the weight ratio of the polypropylene to the cross-linking agent is 100:(0.01-6); preferably 100:(1-5); and more preferably 100:

3.

10. According to the method according to any one of claims 6 to 8, the barbs are obtained by cutting on the surface of the barb with a tool, and the barb parameters are processing length, tangent depth, tangent angle, and processing step as key control points in production, wherein the processing length is set according to the processing suture, the tangent depth is controlled at 0.1-0.6 mm, preferably 0.2-0.5 mm, more preferably 0.3-0.4 mm, the tangent angle is controlled at 20-65 degrees, preferably 35-50 degrees, more preferably 40-45 degrees, and the processing step is controlled at 0.5-3 mm, preferably 0.8-2 mm, more preferably 1-1.5 mm.

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