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 suturing and a preparation method thereof, belonging to the field of medical devices, and in particular to a minimally invasive surgical instrument used in surgical operations, such as arthroscopic soft tissue repair operations. More specifically, the present invention relates to a non-absorbable, knot-free, barbed suture with good tensile strength, wherein the suture is made of a specific non-absorbable material such as polypropylene or polyamide as the suture body, and a knot-free, barbed suture with tensile strength suitable for soft tissue suturing is obtained by optimizing the cross-linking process conditions and matching a suitable outer coating material. Background Art

[0002] The non-absorbable surgical suture for soft tissue suturing, especially the knot-free suture (barb suture) is a special suture material widely used in the medical field, and its remarkable feature is that no traditional knotting operation is required during the entire suturing process. In the 1990s, the United States and Russia disclosed medical barb sutures, which can be used for surgical suturing, removing wrinkles on the face, neck and chest, or lifting skin tissue for cosmetic surgery, as well as wrinkle removal surgery. This design not only simplifies the surgical process, but also improves the efficiency and safety of suturing.

[0003] The design principle of the barbed wire is to use advanced cutting technology to form a series of barbs with a certain angle and 360° spiral distribution on the surface of the suture based on a single strand of suture. After the suture passes through the tissue, these barbs can firmly grasp the tissue like a one-way valve, only moving forward but not backward, thus ensuring the stability of the suture. This design makes the suturing process easier, without the need for additional knotting steps, and also reduces the operation time and the frequency of using the operating forceps.

[0004] Knotless sutures are mainly used in general surgery, orthopedics, obstetrics and gynecology and other fields. 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 situations that require high-strength fixation and reduce the possibility of slippage, such as laparoscopic hepatectomy combined with bile duct suturing, laparoscopic gastroduodenal perforation repair and other surgeries. These applications not only reduce the difficulty of surgery and shorten the operation time, but also reduce the occurrence of complications and promote the recovery of patients.

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

[0006] With the continuous development of new materials, micro-nano technology and 3D printing, the performance of knot-free sutures has been continuously improved and the scope of application has been further expanded. For example, the design of barbed wire has evolved from unidirectional to bidirectional to better meet the needs of different surgical scenarios. At the same time, we continue to explore the application of bioabsorbable materials in knot-free sutures to reduce patients' pain and infection risks.

[0007] The comparison of the therapeutic effects of continuous intradermal suturing with non-absorbable and damage-free sutures and absorbable sutures shows that the key to the success of continuous intradermal suturing with non-absorbable and damage-free sutures is good subcutaneous suturing, which can basically achieve a tension-free state between the sutured skin edges and remove the sutures in time after the wound heals, eliminating the foreign body stimulation and inflammatory reactions of the sutures to the tissues. Therefore, it can significantly reduce the formation of scars, which is beneficial to the patient's skin beauty and avoids functional disorders.

[0008] Commonly used medical barbed wire is a monofilament wire, and the cross-section of the monofilament is generally circular. The manufacturing method of medical barbed wire is to cut barbs on the circular monofilament wire. This method damages the structural integrity of the wire body, so its strength is significantly reduced compared with surgical wires of the same size. During use, the surgical wire is prone to breakage at the side cut of the barb, or the barb falls off. Since the barbs are formed by cutting the surface of the wire body, there are also restrictions on the size and thickness of the barbs; because the top of the barb is too sharp, it irritates the skin tissue and causes discomfort or stimulates the nerves nearby, causing serious medical accidents. In order to minimize the tensile strength of the wire, the barbs are small and sharp, and the anchoring strength of the barbs on the organic tissue is weak, and the knot-free effect is poor. Patents CN102869818A and EP2690206A1 use the method of stamping model sawtooth to make barbed wire. This method is to heat the prefabricated wire in a mold to a temperature below the melting point and above the glass transition temperature to form barbs by applying pressure. Although the wire body is not cut, the prefabricated wire is deformed under heating and pressurizing conditions, which breaks the original physical properties of the wire and damages the original tensile strength of the wire, thereby reducing its use effect.

[0009] As an innovative suture material, knot-free barbed sutures have been widely used in the medical field. However, it also has some problems, especially the problem that barbed sutures are easy to break. The reasons may be as follows: First, the material of the suture. If the material quality of the suture is poor or there are problems in the production process, the suture strength may be insufficient and easy to break. Second, improper suturing technique. If the doctor uses improper techniques during the suturing process, such as excessive traction of the suture during suturing, the suture may be damaged, causing the suture to break easily. Third, excessive patient activity. During wound healing, if the patient is overactive or the wound is subjected to greater tension, the suture may be pulled, causing the suture to break. Fourth, wound infection. If the wound is infected, it may corrode the suture, affecting its strength, and thus causing the suture to break. Fifth, suture aging. Over time, the suture may lose its original strength due to aging, especially in the in vivo environment, the aging process may be accelerated due to the influence of body fluids, causing the suture to break easily. In order to reduce the breakage of barbed sutures, doctors will consider the material and strength of the suture when selecting sutures, and adopt the correct technique during the suturing process to avoid excessive traction of the suture. At the same time, patients should avoid excessive activity during wound healing to reduce pulling on the sutures. If the wound becomes infected, it should be treated in time to reduce the impact on the sutures. Fundamentally, it is still a problem of suture strength. Early barbed sutures may be damaged due to cutting and molding during the production process, affecting the tensile strength of the sutures. Although the second-generation barbed sutures use embossing technology, the strength of the sutures is still a factor that needs to be considered.

[0010] Polypropylene or polyamide sutures are preferred as commonly used non-absorbable suture materials because of their high strength, low relative density, non-absorbency, acid and alkali resistance, non-degradation by body tissues, small tissue reaction, good chemical stability and biological inertness, and the smooth surface of polypropylene or polyamide monofilaments, which can pass smoothly through human tissues during suturing. However, because they are difficult to knot and easy to become disjointed, they are provided with barbs, making them more suitable for soft tissue suturing scenarios. However, the problem of easy breakage of the above-mentioned common barbed sutures has always existed. The present invention unexpectedly discovered 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 filamentary structure elongated body with one or more spaced barbs, which protrude from the surface of the barbed suture along the length direction of the elongated body. The term "filamentary" described in the present invention is used in its most general sense in the present invention and generally refers to an elongated structure. The term "filamentary" generally also refers to and includes a structure having a first axis, which is at least 2 times, at least 10 times, at least 100 times, at least 100 times, or at least 1000 times larger than a second axis perpendicular to the first inner axis, such as a length that is at least twice larger than its diameter. In some embodiments, the average diameter of the filamentary structure over its entire length is 0.1mm to 10mm. In some embodiments, the average diameter of the filamentary structure over its entire length is 1mm to 5mm. In some embodiments, the average diameter of the slender body filamentary structure is less than 1mm. In some embodiments, the average diameter of the filamentary structure is less than 500 microns. In some embodiments, the average diameter of the filamentary structure is less than 250 microns. In some embodiments, the average diameter of the filamentary structure is less than 200 microns. In certain embodiments, the average diameter of the filamentous structure is 20 microns to 5000 microns. In certain embodiments, the average diameter of the filamentous structure is 50 microns to 400 microns. In certain embodiments, the average diameter of the filamentous structure is 70 microns to 350 microns. In certain embodiments, the average diameter of the filamentous structure is 100 microns to 300 microns. In certain embodiments, the average diameter of the filamentous structure is 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 20 microns to 150 microns. In certain embodiments, the average diameter of the filamentous structure is 150 microns to 800 microns.

[0012] The non-absorbable barbed suture described in the present invention is generally prepared using the same material as conventional sutures. More specifically, the non-absorbable suture can be composed of polypropylene or polyamide sutures with a suture needle. The suture needle is a double needle or a single needle. The suture surface has three-dimensional tiny evenly distributed barbs. There is about 0.05-2 cm, preferably 0.075-1.5 cm, and more preferably 0.1-1 cm of no barbs in the center of the suture. The barbs extend to both sides in various ways, such as in an opposing shape, and are connected to the suture needle. The connection is 0.5-5 cm, preferably 1-4 cm, and more preferably 2-3 cm long. More preferably, 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 0.1-0.6mm, preferably 0.2-0.5mm, more preferably 0.3-0.4mm, 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 0.5-3mm, preferably 0.8-2mm, more preferably 1-1.5mm. Preferably, there are three-dimensional tiny barbs on its surface, extending to both sides in an opposing shape and connected to the suture needle. The suture enters the tissue along the barb direction during suturing, and as the barbs of the suture at the other end are opened, they are embedded in the surrounding tissues, and the suture can be fixed in the corresponding position without tying a knot.

[0013] Barbs are configured to allow the barbed suture to pass through tissue in one direction but to prevent the movement of the barbed suture in the opposite direction, so barbed sutures are often used in cosmetic surgery, laparoscopy and endoscopy. The number of barbs required on a particular suture is affected by the size of the wound and the force required to maintain the wound suture. When the wound or the required tissue repair is relatively small, it may be desirable to reduce the number of barbs. 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 complete a tight suture, a bidirectional barbed suture is desired. Various methods such as mechanical cutting, laser cutting, injection molding, stamping, extrusion, etc. can be used to form barbs on sutures. Conventional cutting methods for forming barbs need to be easier to implement, more efficient and more economical in terms of maintaining sharpness, fast movement, and the ability to separate costs. It is necessary to change the size, position, depth, and number of barbs required on the suture. The tool needed for forming the barbed suture can be a blade or a rotating blade, and its geometric shape is for example rectangular, square, circular, flat, star, octagon, triangle, spade, arrow, bolt and ellipse. The barbed suture can be formed with a part of barbs protruding towards one end and the remaining barbs protruding towards the other end to form a plurality of barbs, so as to form a bidirectional barb. The angle of the barbs formed between the barbs and the suture body axial direction is controlled at 20-65 degree, preferably 35-50 degree, more preferably 40-45 degree, most preferably 45 degree. The various cross-sectional geometries before the suture forms the barbs can be circular, ellipse, square, star, octagon, rectangular and flat etc. The arrangement of barbs can form any suitable pattern, for example, spiral, linear or randomly spaced, and the pattern can be symmetrical or asymmetrical, and the number, configuration, interval and surface area of ​​barbs can be changed according to the composition and geometry of the tissue using the barbed suture and the material for forming the suture. In addition, the proportions of the barbs can remain relatively constant, while the total length and barb spacing of the barbs can be determined by the tissue being connected. The barbs formed can include geometric shapes such as circular, triangular, square, oblique, oval, octagonal, rectangular, and flat.

[0014] According to the non-degradable barbed suture constructed according to the present invention, the suitable non-degradable material that can be used to form the barbed suture includes for example polypropylene, polyamide (for example nylon) etc. The filaments and fibers used to form the present invention can be prepared using any technology within the scope of knowledge of the skilled person, for example extrusion, molding and / or solvent casting. As a part of the suture formation process, the filaments themselves can be stretched, oriented, curled, twisted, mixed or air jet entangled to form yarn. When barbs are formed on a medical device, any method within the scope of knowledge of the skilled person can be used to sterilize it. The barbed suture according to the present invention can be coated or impregnated with one or more medical surgical useful materials, which accelerates or beneficially improves the healing process when the medical device is used on a wound or surgical site. In certain embodiments, the coating layer can be formed by a degradable polymer selected from the group consisting of lactones, carbonates, polyorthoesters, hydroxyalkanoates, hydroxybutyrates, bioactive agents, polyanhydrides, siloxanes, calcium stearoyl lactylate, ethylene polymers, high molecular weight paraffin and oils, natural polymers, proteins, polysaccharides, suspendable particles, dispersible particles, microspheres, nanospheres, rods, homopolymers thereof, copolymers thereof and combinations thereof. Suitable bioactive agents include pesticides, antimicrobial agents, antibiotics, inhibitors of cell proliferation, drugs, growth factors, anticoagulants, coagulants, analgesics, anesthetics, anti-inflammatory agents, wound repair agents, etc., chemotherapeutic agents, biological agents, protein therapeutic agents, monoclonal or polyclonal antibodies, DNA, RNA, peptides, polysaccharides, lectins, lipids, probiotics, diagnostic agents, angiogenic 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 on the suture site. Bioactive agent can be selected according to its antimicrobial properties, promotion wound repair and / or tissue growth or special indication disease for example thrombotic ability.Term used herein " antimicrobial " comprises a kind of reagent, and it helps health to kill or resist possible pathogenic microorganism by itself or by auxiliary immune system.Antimicrobial comprises=antibiotic, antiseptic, quorum sensing blocker, antifungal, antiviral, surfactant, metal ion, antimicrobial protein and peptide, antimicrobial polysaccharide, disinfectant and combination thereof.Can use slow-release antimicrobial that enters tissue to help overcome clinical or subclinical infection in surgical operation or trauma wound position in this way.In embodiments, applicable antimicrobial can be dissolved in one or more solvents.The following antimicrobial agents may be used alone or in combination with other biologically active 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 (e.g., urea penicillins, carboxy penicillins, mezlocillin, piperacillin, carbenicillin, ticarcillin and their analogs or derivatives), first generation cephalosporins (e.g., cefazolin sodium, cephalexin, cefazolin , cefoperazone, and cephalothin), carboxypenicillins (e.g., ticarcillin), second-generation cephalosporins (e.g., cefuroxime, cefotetan, and cefoxitin), third-generation cephalosporins (e.g., ceftiofur, cefdinir, cefoperazone, ceftazidime, ceftriaxone, and ceftriaxone), polyvinylpyrrolidone, fourth-generation cephalosporins (e.g., cefepime), monobactams (e.g., aztreonam), carbapenems (e.g., imipenem, etapenem (meropenem), aminoglycosides (e.g., streptomycin, gentamicin, tobramycin, and amikacin), members of the MSL group (e.g., macrolides, long-acting macrolides, lincosamide, streptogramins, erythromycin, azithromycin), lincomycin, clindamycin, snorodoxime, clarithromycin and kanamycin sulfate), tetracyclines such as minocycline, fusidic acid, trimethoprim, metronidazole, quinolones (e.g., ciprofloxacin, ofloxacin, gatifloxacin, moxifloxacin, levofloxacin and trovafloxacin), DNA synthesis inhibitors (e.g., metronidazole), sulfonamides (e.g., 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, azoles such as fluconazole, and Other antimicrobial agents. According to the barbed suture of the present invention, it can also include, for example, biologically acceptable plasticizers, antioxidants and colorants, which can be immersed in the silk used to form the suture of the present disclosure or included in the coating thereon. The method within the scope of those skilled in the art can be used to apply the bioactive agent to the barbed medical device of the present disclosure, such as dipping, spraying, vapor deposition, brushing, solvent evaporation, mixing, etc. The barbed suture of the present invention can be dyed to increase the visibility of the workpiece in the surgical area. Any dye suitable for introducing the medical device can be used, and the dye can be dyed by adding the dye of the amount up to about several percentages.

[0015] The suture of the present invention can include a needle at one end. In order to facilitate the attachment of the needle to the suture, conventional tipped agents can be applied in the braiding. Sutures with tips added to both ends may be desirable to attach needles to each end of the suture to provide a double needle suture. The attachment of the needle can be carried out using any conventional method such as curling, molding, etc. In certain embodiments, the diameter of the needle is less than, equal to, or greater than the diameter of the surgical suture compared to the diameter of the surgical suture. In certain embodiments, the needle is selected from the group comprising the following: straight needle, 1 / 4 round needle, 3 / 8 round needle, 1 / 2 round needle, 5 / 8 round needle, compound curve needle, semi-curved (also called ski-shaped) needle and semi-curved needles at both ends of the straight section (also called canoe-shaped) needle. Needles can also be classified according to their tip geometry; examples include: tapered needles (needle body is round and tapers smoothly to a point); scoring needles (needle body is triangular and has a sharp blade on the inner curve); reverse scoring needles (with a blade on the outside); primary cutting needles; trocar tip or conical cut (needle body is round and tapered, but the end is a small triangular cutting tip); blunt tip for suturing delicate tissue; side cutting or spatula tip for ophthalmic surgery (flat on top and bottom, cutting edge from front to side). Each possibility represents a separate embodiment of the invention. In certain embodiments, the needle is hard 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 0.01mm. In certain embodiments, the surgical suture is inserted into the skin or subcutaneous layer up to 5mm. In certain embodiments, the surgical suture is inserted into the skin or subcutaneous layer 0.01mm to 5mm. In certain embodiments, the surgical suture is inserted into the skin or subcutaneous layer 1mm to 2mm. 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 below the epidermis. In certain embodiments, the surgical suture is inserted below the dermis. In certain embodiments, the surgical suture is inserted below the subcutaneous layer. Each possibility represents a separate embodiment of the present invention.

[0017] The barbed sutures and placement methods applicable according to the present invention are well known in the art. For example, the sutures can be used to elevate tissues, which is desirable in certain cosmetic surgeries. In certain embodiments, the method of suturing tissues using barbed sutures includes inserting the first end of a suture optionally attached to a needle at an insertion point on the surface of the human body. The first end of the suture can be pushed through soft tissue until the end extends out of the soft tissue at the exit point. The first end of the suture can then be grasped and pulled to pass the first portion of the suture through the soft tissue so that a section of the first portion of the suture remains in the soft tissue between the insertion point and the exit point at the first end. The soft tissues can then be manually grouped and lifted along at least a portion of the suture to obtain the desired amount of elevation. The suture can be used as a minimally invasive surgical instrument in any cosmetic, plastic surgery, open endoscopy or laparoscopy method, and can also be used to attach one tissue to another, including, but not limited to, attaching tissue to a ligament. Specific applications of cosmetic surgery include, for example, face 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 exemplifications of its embodiments. Those skilled in the art will envision many other possibilities within the scope and spirit of the present invention as defined by the appended claims.

[0018] The non-absorbable surgical sutures described in the present invention, especially the preparation method of the knot-free barbed sutures, control and enhance the tensile strength of the sutures described in the present invention through the following key steps. Specifically, it includes: 1. Preparation of spinning raw materials: suitable medical suture materials, such as polypropylene, polyamide, etc., are extruded and sliced ​​through a twin-screw extruder to obtain spinning raw materials; 2. Spinning: Dry the spinning raw materials to a moisture content of less than 0.005wt%, add them to the spinning machine for spinning, and obtain primary fibers after cooling the filaments; 3. Chemical crosslinking: The fibers obtained by spinning are chemically crosslinked to enhance their physical and mechanical properties; 4. Barb formation: Use a clamp to clamp the head and end of the crosslinked fiber raw filaments, and obtain barbed sutures after treatment. Furthermore, the barbed sutures are cut and needled, wound and packaged, sterilized, and sealed to obtain knot-free barbed sutures.

[0019] In order to further enhance the tensile strength of the suture of the present invention, the following treatments may be performed, such as stretching: the obtained primary fiber is stretched to obtain fiber precursors; antibacterial treatment: in order to reduce the risk of wound infection, the suture is subjected to antibacterial treatment. Post-treatment: the suture after cross-linking and antibacterial treatment may also undergo post-treatment steps such as cleaning and drying as needed to remove residual chemicals to ensure the safety and biocompatibility of the suture. In order to facilitate the user to quickly identify and use different types of sutures, dyeing treatment may be performed: the fiber precursor is immersed in a solution tank containing a dyeing substance and then dried to obtain the dyed fiber precursor; performance testing: the completed suture is subjected to physical and mechanical performance tests in accordance with 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 above-mentioned non-absorbable surgical sutures of the present invention, especially the preparation method of knot-free barbed sutures, further, the spinning raw material is preferably further, a suitable polypropylene raw material, especially a polypropylene with a viscosity average molecular weight of more than 1 million, preferably 1 million to 6 million, more preferably more than 2 million, and its molecular weight distribution is between 3.5 and 4.8, preferably between 4 and 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 decahydronaphthalene solution at 135°C, and the characteristic viscosity [η] of the polypropylene resin is determined according to the method of GB / T1632.3-2010 "Determination of viscosity of dilute polymer solutions by capillary viscometer for plastics, Part 3: Polyethylene and polypropylene". Then substitute into the formula M=K·[η], where K=53700, α=1.49, the viscosity average molecular weight M can be calculated. The molecular weight distribution of polypropylene was determined as follows: using a high temperature gel permeation chromatograph, with 1,2,4-trichlorobenzene as solvent, a solution concentration of 1.0 mg / ml, a test temperature of 150°C, and a solution flow rate of 1.0 ml / min.

[0021] Furthermore, the non-absorbable surgical sutures described in the present invention, especially the preparation method of knot-free barbed sutures, can be made into fibers by melt spinning or wet spinning during 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, extrude it into a coagulation bath and coagulate it into filaments. Chemical crosslinking usually uses crosslinking agents such as epoxy soybean oil, genipin, diisopropylbenzene peroxide (DCP), divinylbenzene (DVB), etc., wherein 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); further 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 sutures. The non-absorbable surgical sutures described in the present invention, especially the method for preparing knot-free barbed sutures, wherein the barbed sutures can be formed by direct film pressing, or the barbed sutures can be obtained by cutting the surface of the sutures with a knife. The non-absorbable surgical sutures described in the present invention, especially the method for preparing knot-free barbed sutures, wherein the antibacterial treatment is achieved by coating the surface of the sutures with an antibacterial agent, such as a broad-spectrum antibacterial agent such as triclosan. Antibacterial agents can inhibit bacterial growth and reduce the chance of infection. Through the above steps, these sutures can provide better wound closure effects in medical operations while reducing the risk of infection.

[0022] The non-absorbable surgical suture of the present invention, especially the preparation method of knot-free barbed suture, wherein the melt spinning is to add the polypropylene raw material into the 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 80-350s. The polypropylene obtained by cooling and granulating the extrudate is spun into shape by a spinning machine, the temperature of the spinning zone 1, the temperature of the second zone, and the temperature of the third zone are adjusted according to the formula, and the parameters such as the nozzle diameter, the material rod advancement speed, the extrusion line speed, and the winding line speed of the spinning machine are selected or controlled, and the spun primary fiber is stretched by a certain multiple through a hot plate stretching machine to enhance the strength and toughness of the fiber. Through tense heat setting to stabilize the structure of the fiber, impregnation and coating are performed 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 according to conventional methods in the field. Furthermore, 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 box 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 box is 147°C. The diameter of the nozzle of the spinning machine is 0.6-1.0mm, the feed rod advancement speed is 3.3-4.6mm / min, the extrusion line speed is 0.5-0.8m / min, and the winding line speed is 13-17m / min. Preferably, the diameter of the nozzle of the spinning machine is 1 mm, the material rod advancement speed 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 of the present invention, especially the preparation method of the knot-free barbed suture, wherein the dyeing is a dye bath immersion dyeing commonly known in the art, in some embodiments, the specific steps of dyeing are: immersing the fiber precursor in a solution tank containing a dyeing substance at a speed of 0.2-0.6 m / min, keeping the fiber passing through the solution tank for 15-33 min, and then drying the fiber precursor impregnated with the dyeing substance at 32-46 ° C to obtain the dyed fiber precursor. Further, in the specific process of cutting the barbs in the preparation method, the fiber precursor rotates axially, and the line rotates at a rate of 1-5s / turn, preferably 2-4s / turn, and more preferably 3s / turn. The prepared suture has about 0.05-2cm, preferably 0.075-1.5cm, and more preferably 0.1-1cm without barbs in the middle, and the barbs extend to both sides in an opposite shape, and are connected to the suture needle, and the connection is 0.5-5cm, preferably 1-4cm, and more preferably 2-3cm long. More preferably, 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 0.1-0.6mm, preferably 0.2-0.5mm, more preferably 0.3-0.4mm, 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 0.5-3mm, preferably 0.8-2mm, more preferably 1-1.5mm.

[0024] The present invention provides a knotless barbed suture prepared by any one of the above-mentioned preparation processes. Compared with the prior art, the present invention effectively solves the problem that the knotless barbed suture is easy to break by selecting suitable suture materials, selecting a chemical cross-linking method within a suitable range, and optimizing the selected specific structure, presents excellent tensile properties, and is safer and more reliable for clinical use. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0027] Example 1

[0028] The first aspect of the present embodiment provides a method for preparing a knot-free barbed suture, comprising the following steps: preparing spinning raw materials: mixing polypropylene, extruding through a twin-screw extruder at 115° C., and slicing to obtain spinning raw materials; spinning: drying the spinning raw materials to a moisture content of less than 0.005wt%, adding them to a spinning machine for spinning, and cooling the filaments with alcohol to obtain primary fibers; stretching: stretching the fibers to obtain fiber precursors, performing water bath stretching once, and hot plate stretching twice to obtain fiber precursors; chemical crosslinking: chemically crosslinking the fibers to enhance their physical and mechanical properties; Dyeing: Dip the fiber precursor into a solution tank containing dyeing substances at a speed of 0.3 m / min, keep the fiber passing through the solution tank for 20 minutes, and then dry the fiber precursor impregnated with dyeing substances at 40°C to obtain the dyed fiber precursor, and the original USP size of the dyed fiber precursor is 3-0; Cutting and stabbing: Use a clamp to clamp the ends of the dyed fiber precursor, and use a knife to cut the surface of the dyed fiber precursor to obtain a barbed suture. During the cutting process, the dyed fiber precursor rotates axially, and the line rotation rate is 3s / turn. The barbed suture is cut and needled, wound and packaged, sterilized, and sealed to obtain a knot-free barbed suture. During the spinning process: the heating temperature of screw zone 1 is 135°C, the heating temperature of screw zone 2 is 145°C, the heating temperature of screw zone 3 is 140°C, the heating temperature of the flange is 145°C, and the heating temperature of the box is 145°C; the diameter of the spinning machine nozzle is 0.8mm, the rod advancement speed is 3.5mm / min, the extrusion line speed is 0.6m / min, and the winding line speed is 15m / min; the temperature of the first water bath stretching is 40°C and the stretching multiple is 3 times, the temperature of the first hot plate stretching is 60°C and the stretching multiple is 8 times, the temperature of the second hot plate stretching is 50°C and the stretching multiple is 5 times; there are 8 barbs per centimeter on the barbed suture; the angle between the barb and the thread body is 20°.

[0029] The knotless barbed suture prepared in Example 1 was tested for tensile strength, elongation at break, etc. in a standard manner.

[0030] Embodiment 2-5

[0031] Example 2-5 provides a method for preparing a knot-free barbed suture, and its specific implementation method is the same as that of Example 1, except that the corresponding conditions are adjusted and the suture is prepared by a person of ordinary skill in the art according to the method of Example 1.

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

[0033] Table 1

[0034]

[0035] The polypropylene described in Table 1 is a conventional commercial product, high molecular weight polypropylene refers to polypropylene with a viscosity average molecular weight of more than 1 million, and ultra-high molecular weight polypropylene refers to polypropylene with a viscosity average molecular weight of more than 2 million. The results show that after treatment, the tensile strength and elongation at break of the barbed suture show unexpected and significant improvements, especially the high molecular weight polypropylene with a viscosity average molecular weight of more than 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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