A barbed suture and method of making same

Abstract

The application provides a barbed suture and a preparation method thereof, and relates to the fields of surgery and medical cosmetology. The preparation method of the barbed suture comprises the following steps: S1, extruding a thin-walled hollow tube through an extruder; S2, performing hot cutting on the wall of the hollow tube to form a barb; and S3, cutting along the axial direction of the hollow tube to form a non-through wall incision belt. The preparation method of the barbed suture provided by the application extrudes a thin-walled hollow tube through extrusion molding, then performs hot cutting to form a barb on the tube wall, and forms an incision belt through non-through cutting along the axial direction, so that the suture has better flexibility, the barb generated by hot cutting enhances the anchoring force, and the stability of the suture in the tissue is ensured. In addition, the non-through design of the incision belt increases the ductility of the suture, so that the suture can adapt to tissue activities and the possibility of rupture is reduced, thereby improving the reliability and clinical effect of the suture.

Description

Technical Field

[0001] This invention relates to the fields of surgery and medical aesthetics, and in particular to a barbed suture and its preparation method. Background Technology

[0002] Surgical barbed sutures are widely used because they eliminate the need for knotting and can create bidirectional or unidirectional self-locking anchorage within tissue. Common manufacturing methods for existing products include: mechanically / laser cutting solid monofilaments to form barbs, or using a segmented design with bidirectional barbs to adapt to different suturing scenarios. Some literature also proposes forming a sheath or covering sheet outside the core material and then creating barbs on the outer layer to control the barb geometry and surface properties.

[0003] However, existing methods based on solid monofilament barb formation present several technical challenges. One is that the overall torsional stiffness of the suture tends to increase after barb formation, leading to insufficient suture compliance when bending, passing through catheters, or using puncture cannulas, thus affecting surgical flexibility and suturing effectiveness. Furthermore, while twisting and heat-setting the monofilament can improve barb distribution to achieve a more uniform circumferential distribution, this can easily lead to the accumulation of net torque during clinical traction, causing the suture to tend to twist and fold, thereby affecting the stability and reliability of the suture. Summary of the Invention

[0004] To address the issue of insufficient flexibility in tissues in existing barbed sutures, this invention provides a barbed suture and its preparation method. A thin-walled hollow tube is obtained through extrusion molding, followed by thermal cutting to form barbs on the tube wall. A non-through-cutting along the axial direction forms a suture band, resulting in improved flexibility while the barbs from thermal cutting enhance anchoring force, ensuring suture stability in tissues. Furthermore, the non-through-cutting design increases the suture's extensibility, allowing it to adapt to tissue movement and reducing the likelihood of breakage, thereby improving suture reliability and clinical efficacy.

[0005] The technical solution adopted by this invention to solve its technical problem is: A method for preparing a barbed suture, characterized by comprising the following steps: S1: Extruding thin-walled hollow tubes using an extruder; S2: Hot cutting is performed on the wall of the hollow tube to form barbs; S3: Cut along the axial direction of the hollow tube to form a slit strip that does not penetrate the tube wall.

[0006] Optionally, the hollow tube is made by extrusion of a thermoplastic polymer.

[0007] Optionally, the ratio of the wall thickness to the outer diameter of the hollow tube is 0.10 to 0.15.

[0008] Optionally, the hot cutting processing temperature is higher than the glass transition temperature of the thermoplastic polymer but lower than its melting point.

[0009] Optionally, the lifting angle between the barb and the axis of the hollow tube is 20° to 45°.

[0010] Optionally, the residual wall thickness at the cut strip is 0.30 to 0.50 of the wall thickness.

[0011] Optionally, the slit strip is obtained by vertical cutting with axial feed and radial advance.

[0012] Optionally, after obtaining the hollow tube in step S1, the hollow tube is further subjected to stretching and orientation.

[0013] Optionally, the ratio of the distance between adjacent cuts on the slit strip to the outer diameter of the hollow tube is 4 to 6.

[0014] Another object of the present invention is to provide a barbed suture, which is prepared by the barbed suture preparation method described above.

[0015] The beneficial effects of this invention are: The barbed suture and its preparation method provided by this invention significantly improve the overall performance and flexibility of the suture by forming barbs through thermal cutting on the wall of a thin-walled hollow tube and forming a slit band through non-penetrating cutting along the axial direction. Specifically, this invention manufactures a thin-walled hollow tube using an extruder, effectively reducing the weight of the suture and improving its adaptability in complex tissue structures, thereby significantly improving flexibility and reducing potential tissue damage. Simultaneously, this application uses thermal cutting technology to form barbs on the hollow tube wall, ensuring that small barbs are precisely lifted and shaped while being cut off, ensuring that the barbs provide effective anchorage in the tissue and improving the functionality of the suture. Furthermore, by performing deep non-penetrating cutting on the tube wall to form discontinuous weak points, the suture's extensibility and flexibility are significantly enhanced, effectively avoiding the torsion effect caused by material stiffness, thereby improving the reliability and service life of the suture. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a flowchart illustrating the preparation process of the barbed suture in this invention. Detailed Implementation

[0018] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] To address the problem of insufficient flexibility of barbed sutures in tissues in existing technologies, this invention provides a method for preparing barbed sutures, comprising the following steps: S1: extruding a thin-walled hollow tube using an extruder; S2: performing thermal cutting on the wall of the hollow tube to form barbs; S3: cutting along the axial direction of the hollow tube to form a non-through-the-wall suture band.

[0021] The barbed suture and its preparation method provided by this invention significantly improve the overall performance and flexibility of the suture by forming barbs through thermal cutting on the wall of a thin-walled hollow tube and forming a slit band through non-penetrating cutting along the axial direction. Specifically, this invention manufactures a thin-walled hollow tube using an extruder, effectively reducing the weight of the suture and improving its adaptability in complex tissue structures, thereby significantly improving flexibility and reducing potential tissue damage. Simultaneously, this application uses thermal cutting technology to form barbs on the hollow tube wall, ensuring that small barbs are precisely lifted and shaped while being cut off, ensuring that the barbs provide effective anchorage in the tissue and improving the functionality of the suture. Furthermore, by performing deep non-penetrating cutting on the tube wall to form discontinuous weak points, the suture's extensibility and flexibility are significantly enhanced, effectively avoiding the torsion effect caused by material stiffness, thereby improving the reliability and service life of the suture.

[0022] The hollow tubes of this invention are preferably made by extrusion of thermoplastic polymers; further, the thermoplastic polymer is preferably polydioxanone (PDO), polymer particles are injected at the melting temperature of PDO, and uniform hollow tubes are manufactured by extrusion molding technology, which ensures the uniformity and consistency of the material.

[0023] To maximize the flexibility of the suture while ensuring sufficient mechanical strength, this invention preferably uses a hollow tube with a wall thickness to outer diameter ratio of 0.10–0.15. This ratio range avoids structural instability and processing defects that may occur with excessively thin walls, such as barb breakage or root tearing, while preventing suture stiffness caused by excessively thick walls, thus ensuring its adaptability and flexibility during surgical procedures. Furthermore, this design reduces damage to surrounding tissues, helps reduce postoperative inflammation, and thereby improves patient healing quality and comfort, significantly enhancing the practicality and clinical application value of the suture.

[0024] The present invention preferably uses a hot cutting processing temperature higher than the glass transition temperature of the thermoplastic polymer but lower than its melting point; further, it is preferred that the hot cutting processing temperature is 85°C to 90°C, which can cut the polymer material more cleanly, ensure the formation of the barb, and accurately lift and shape it to form an effective hook barb structure; further, it is preferred that the lifting angle between the barb and the axis of the hollow tube is 20° to 45°, which can avoid material cracking or the generation of internal stress microcracks, ensure a seamless transition and metallurgical-grade bonding strength between the barb root and the substrate, and eliminate the risk of barb delamination from the interface.

[0025] Furthermore, the residual wall thickness at the suture band is preferably 0.30 to 0.50 times the wall thickness, which gives the suture excellent ductility, effectively prevents the occurrence of torsion effects, and allows the suture to stretch appropriately when subjected to tensile force, reducing stress concentration and lowering the possibility of breakage. This is because when the residual wall thickness is less than 0.30 times the wall thickness, it increases the risk of stress concentration and crack propagation at the root of the incision, shortening fatigue life; while exceeding 0.50 times will make the suture too stiff, unable to adapt to tissue deformation, increasing the risk of structural failure.

[0026] The present invention preferably obtains the suture band through vertical cutting with axial movement and radial advance; this ensures the precision and consistency of the cut, achieving not only a uniform distribution of the suture band but also helping to evenly distribute stress throughout the suture, thereby enhancing the suture's extensibility and torsional resistance. Simultaneously, the clear cut produced by vertical cutting reduces burrs and debris, further improving the suture's surface quality and overall functionality.

[0027] The present invention preferably uses a ratio of 4 to 6 between the distance between adjacent incisions on the suture band and the outer diameter of the hollow tube to ensure a sufficiently long uncut material segment between adjacent incisions. This is crucial for maintaining the key performance characteristics of the suture. First, this intact material segment is the main part that bears the axial tensile force, and its length is essential to meeting the crack arrest requirements. This ensures that even with multiple incisions, the overall tensile strength of the suture will not be significantly reduced. Second, it helps maintain the continuity and circumferential stiffness of the tube blank, preventing the suture from becoming too soft due to excessively dense incisions, thus losing its ability to pass through tissue. The distance between adjacent incisions on the suture band refers to the distance between the centerlines of two adjacent incisions along the axial direction of the hollow tube.

[0028] To improve the mechanical properties of the suture, including tensile strength and elastic modulus, making it more suitable for withstanding the tensile forces during surgery, the present invention preferably includes a stretching and orientation process for the hollow tube after obtaining the hollow tube in step S1.

[0029] Another object of the present invention is to provide a barbed suture, which is prepared by the barbed suture preparation method described above.

[0030] The barbed suture prepared by this invention uses a thin-walled hollow tube manufactured by extrusion molding technology as the substrate, which effectively avoids the interlayer separation problem common in traditional composite sutures. Secondly, compared with the tubular preforms manufactured by traditional methods, which have a large wall thickness and insufficient flexibility, the suture of this invention exhibits significant flexibility and extensibility, and can better adapt to tissue movement, reducing tissue damage. At the same time, through precise control of the wall thickness to outer diameter ratio and the design of the cutting band, the adaptability of the suture of this invention to tissue movement is further enhanced.

[0031] Furthermore, the barbs formed on the tube wall using thermal cutting technology in this invention achieve complete integration with the substrate. This integrated structure significantly improves the anchoring strength of the barbs, thereby enhancing the stability of the suture. The reasonable residual wall thickness and incision spacing design also contribute to the uniform distribution of stress, reducing stress concentration and effectively improving the fatigue resistance and impact resistance of the suture. Moreover, the design of the incision layout further enhances the anti-kinking ability, ensuring its high reliability and effectiveness in clinical applications.

[0032] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a barbed suture, characterized in that, Includes the following steps: S1: Extruding thin-walled hollow tubes using an extruder; S2: Hot cutting is performed on the wall of the hollow tube to form barbs; Hot cutting technology is used to form barbs on the hollow tube wall, ensuring that small barbs are cut off while being precisely lifted and shaped. S3: Cut along the axial direction of the hollow tube to form a slit strip that does not penetrate the tube wall; The ratio of the wall thickness to the outer diameter of the hollow tube is 0.10 to 0.15; The residual wall thickness at the cut strip is 0.30 to 0.50 of the wall thickness; The ratio of the distance between adjacent cuts on the slit strip to the outer diameter of the hollow tube is 4 to 6.

2. The method for preparing the barbed suture as described in claim 1, characterized in that, The hollow tube is made by extrusion of a thermoplastic polymer.

3. The method for preparing the barbed suture as described in claim 2, characterized in that, The hot cutting process temperature is higher than the glass transition temperature of the thermoplastic polymer but lower than its melting point.

4. The method for preparing the barbed suture as described in claim 1, characterized in that, The lifting angle between the barb and the axis of the hollow tube is 20° to 45°.

5. The method for preparing the barbed suture as described in claim 1, characterized in that, The slit strip is obtained by vertical cutting with axial feed and radial advance.

6. The method for preparing the barbed suture as described in claim 1, characterized in that, After obtaining the hollow tube in step S1, the process further includes stretching and orienting the hollow tube.

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