Method of forming a medical stent

Abstract

The application relates to a forming method of a medical stent. The forming method is used for processing the medical stent, and the forming method comprises the following steps: a plurality of first wires are at least partially interwoven with a plurality of second wires along a first direction to form a mesh, so that a first preliminary blank is obtained; the first preliminary blank is heat set, so that a second preliminary blank is obtained; and the intersection nodes of the first wires and the second wires are fixed to fix the first wires and the second wires, so that a third preliminary blank is obtained. The forming method of the medical stent can effectively stabilize the shape of the whole mesh structure after interweaving, eliminate the interweaving stress, greatly enhance the overall structural strength and connection reliability of the stent, prevent the mesh structure from being loose and deformed during use, gradually optimize the structural performance of the stent through the step-by-step forming process, take into account the flexible implanting characteristics and the structural stability during long-term use of the stent, and effectively improve the finished product quality and the clinical use safety of the medical stent.

Description

Technical Field

[0001] This application relates to the field of medical device manufacturing technology, and in particular to a method for forming medical stents. Background Technology

[0002] In radical prostatectomy (RP), after the prostate is removed, the bladder end and urethral end need to be reanastomosed to restore the continuity of the urinary tract.

[0003] In related technologies, a medical stent is placed between the bladder end and the urethral end. After suturing the bladder end and the urethral end, the medical stent is used to cover the suture site of the bladder end and the urethral end to help improve the stability of the anastomosis between the bladder end and the urethral end.

[0004] In the above-mentioned medical stent forming process, multiple wires are woven together in a first direction and a second direction to form a mesh, and then the intersection points of the multiple wires are welded and fixed to form a medical stent.

[0005] However, in the above-mentioned forming method, the cross nodes are directly welded and fixed after the mesh is woven, and the medical stent is only connected and fixed through the connection of the cross nodes to achieve the overall structure. Because the wire may have torque or bends other than those for forming, the welded cross nodes of the medical stent are prone to loosening or even breaking due to the external forces such as torque or bending. Summary of the Invention

[0006] Therefore, it is necessary to provide a method for forming a medical stent to address the problem that the welded intersections of medical stents are prone to loosening or even disconnection under the action of external forces such as torque or bending.

[0007] A method for forming a medical stent, used to process a medical stent, the method comprising:

[0008] Multiple first wires are interwoven at least partially along a first direction and multiple second wires are interwoven at least partially along a second direction to form a mesh, thereby obtaining a first blank;

[0009] The first preliminary billet is heat-set to obtain the second preliminary billet;

[0010] Fix the intersection of the first wire and the second wire to secure the first wire and the second wire, and obtain the third initial blank.

[0011] The molding method of this medical stent involves heat-setting the first blank before welding the cross nodes. This effectively stabilizes the overall mesh structure after weaving, eliminates weaving stress, and improves the dimensional stability and structural regularity of the stent. Finally, the cross nodes of the first and second wires are welded and fixed, which can prevent the weaving nodes from loosening, slipping, or misaligning. This significantly enhances the overall structural strength and connection reliability of the stent, and prevents the mesh structure from loosening and deforming during use. At the same time, the step-by-step molding process gradually optimizes the structural performance of the stent, taking into account both the flexible implantation characteristics of the stent and the structural stability for long-term use, effectively improving the finished product quality and clinical safety of the medical stent.

[0012] In one embodiment, the step of heat-setting the first preliminary billet to obtain the second preliminary billet includes:

[0013] The cross node is heated at a first preset temperature for a first preset duration.

[0014] The above forming method can completely eliminate residual internal stresses such as torsion, tension, and bending generated during the cross-weaving process of the wires, allowing the overall structure of the stent woven mesh to fully relax and solidify, unifying and standardizing the overall shape and dimensional accuracy, avoiding later deformation, warping, and shrinkage problems caused by localized residual stress, uniformly optimizing the microstructure and mechanical state of the wire material, ensuring the consistency of form and performance of each component of the first support, second support, and connector, improving the overall structural regularity and morphological stability of the woven blank, providing reliable structural protection for subsequent cross-node welding, component splicing and assembly, and deformation rebound and flexible support performance during stent implantation and use, effectively reducing the defect rate of finished products, and enhancing the overall structural reliability and clinical suitability of the modular medical stent.

[0015] In one embodiment, the first preset temperature is 60°C-90°C;

[0016] And / or, the first preset duration is 5min-20min.

[0017] This temperature range can match the thermal properties of absorbable polymer materials. Within this temperature range, the first woven blank is heated and shaped at a constant temperature, which can gently and fully release the residual internal stress generated during the torsion, stretching, and bending of the monofilament during weaving. This promotes the overall relaxation and regularity of the mesh structure, and accurately stabilizes the shape and weaving form of each component.

[0018] The first preset duration can be synergistically adapted to the setting temperature. The short duration range can adapt to the stress relaxation characteristics of absorbable polymers such as polylactic acid, polycaprolactone, and polydioxanone. While effectively eliminating the residual internal stress caused by torsion, tension, and bending generated by monofilament weaving, it can fully relax and regularize the mesh structure of the first blank, stabilizing the overall size and weaving morphology.

[0019] In one embodiment, the step of fixing the intersection of the first wire and the second wire to fix the first wire and the second wire and obtain the third blank includes:

[0020] Fix the intersection node.

[0021] After step S2, where the first preform has undergone heat setting to release stress and stabilize its shape, the intersections of the first and second wires are welded together. This welds the intersections of the first and second wires to form an integrated connection structure, effectively limiting relative slippage, misalignment, and loosening between adjacent filaments, locking the arrangement of the mesh weave structure, and significantly improving the overall density and mechanical integrity of the third preform. Combining the properties of absorbable polymer materials with a modular component design, the node welding evenly distributes the stress on the scaffold, improving localized stress concentration, maintaining the structural integrity of the first support, second support, and connectors, and preventing the mesh from loosening and deforming during compression, expansion, and implantation. It also enhances the dimensional stability and molding consistency of each component, providing structural support for subsequent scaffold assembly, in vivo deformation adaptation, and stable degradation.

[0022] In one embodiment, the method for fixing the intersection node includes one of the following methods:

[0023] All the aforementioned cross nodes were heat-welded;

[0024] All the aforementioned cross nodes were ultrasonically welded;

[0025] The cross joints are partially heat-welded, and the remaining cross joints are ultrasonically welded.

[0026] The above-mentioned multiple welding methods offer flexible options, effectively locking the interlacing position of the first and second wires, reducing the risk of slippage, loosening, and cracking of the braided nodes, strengthening the overall structural strength and dimensional stability of the third blank, and precisely controlling the welding heat input range to avoid large-scale high-temperature damage to the flexibility, biocompatibility, and degradation performance of the stent substrate. This ensures uniform mechanical properties of each component, reduces residual welding stress, improves the expansion and rebound capacity and bending resistance of the mesh stent, effectively adapts to the subsequent assembly of split-type absorbable medical stents and the deformation requirements of complex cavities in the body, reduces the risk of structural failure after implantation, and ensures product processing yield and clinical safety.

[0027] In one embodiment, the step of thermally welding all the cross nodes includes:

[0028] The heating tool, heated to a second preset temperature, is brought into contact with the intersection node for a second preset duration.

[0029] The second preset temperature is 120℃-180℃;

[0030] The second preset duration is 0.5s-2s.

[0031] This step involves using a heating tool heated to 120℃-180℃ to briefly contact the cross-node for 0.5s-2s to achieve targeted thermal welding. Relying on the processing mode of instantaneous high temperature and short contact, it can accurately and rapidly melt and bond the cross-nodes of absorbable polymer materials. The short-term high temperature effect is concentrated only in a very small area of ​​the node. The heat input is concentrated and the action time is extremely short, which can quickly complete the node welding and shaping, lock the relative position of the wires, and effectively prevent the braided nodes from slipping and loosening.

[0032] In one embodiment, when the heating tool comes into contact with the cross node, the heating tool abuts against the cross node with a first preset pressure.

[0033] During the material melting stage at the intersection, the first and second wires are brought into close contact, compressing the gap between the wires and improving the fusion tightness and uniformity of the molten interface, thus avoiding incomplete welding and desoldering. At the same time, the pressure can help the molten polymer material spread and penetrate rapidly, enhancing the bonding strength and structural integrity of the intersection, and preventing the node from cracking or loosening under stress.

[0034] In one embodiment, the process parameters for all the cross-node steps of the ultrasonic welding include a second preset pressure, a third preset duration, and a preset frequency.

[0035] The second preset pressure is 0.1 MPa - 0.5 MPa;

[0036] The third preset duration is 0.1s-1s;

[0037] The preset frequency is 20kHz-40kHz.

[0038] In this ultrasonic welding process parameter specification, appropriate pressure ensures a tight fit between the first and second wires at the intersection, providing stable contact conditions for high-frequency vibration welding. This avoids insufficient pressure leading to weak bonding or excessive pressure causing wire deformation and structural damage. Simultaneously, the shorter welding time enables instantaneous localized frictional heat generation and melting, significantly reducing the heat-affected zone and effectively mitigating the problems of molecular chain damage, performance degradation, and abnormal degradation rates in absorbable materials such as polylactic acid, polycaprolactone, and polydioxanone due to prolonged heating.

[0039] In one embodiment, the first preform is either a first support member or a second support member, and the first support member and the second support member are separate structures. Separate structures help reduce molding difficulty, and the first support member can also be set with different axial dimensions to accommodate individual differences among different patients.

[0040] In one embodiment, after welding the intersection of the first wire and the second wire to fix the first wire and the second wire and obtaining the third preliminary blank, the method further includes:

[0041] The third blank is deburred, cleaned and dried in sequence to obtain a first support, a second support or a connector. The first support and the second support can be connected by the connector to form the medical stent.

[0042] After the cross-node welding and shaping of the third initial blank is completed, deburring, cleaning, and drying are performed sequentially to obtain the first support component, second support component, or connector. This effectively removes burrs, flash, and local protrusions generated during welding and weaving, eliminates sharp structures, avoids scratching human tissue during implantation, and improves product safety. The cleaning process thoroughly removes residual impurities, dust, and trace processing residues, ensuring the surface cleanliness of the absorbable scaffold components, maintaining good biocompatibility of the material, and preventing adverse reactions such as postoperative inflammation and irritation caused by foreign bodies. Subsequent drying completely removes residual moisture from the cleaning process, preventing premature degradation, material deterioration, and performance decline of absorbable polymer materials due to long-term moisture exposure. It stabilizes the component dimensions and mechanical properties, further optimizes the surface finish and appearance quality of the scaffold, and ensures the processing consistency and structural integrity of each component in a modular design. This provides a clean, orderly, and stable foundation for subsequent precise assembly, clinical implantation, and stable degradation in vivo. Attached Figure Description

[0043] Figure 1 This is a logic diagram of a method for forming a medical stent provided in one embodiment of this application.

[0044] Figure 2 This is a schematic diagram of the structure of a medical stent provided in one embodiment of this application.

[0045] Explanation of reference numerals in the attached figures:

[0046] 100 - First support member; 200 - Second support member; 300 - Connector. Detailed Implementation

[0047] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0048] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0049] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0051] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0053] See Figure 1 , Figure 1 A logic diagram of a method for forming a medical stent according to an embodiment of this application is shown.

[0054] like Figure 1 As shown, this embodiment provides a method for forming a medical stent, which is used to process the medical stent. The medical stent is configured to reshape the connection between a first tissue portion and a second tissue portion. Exemplarily, this medical stent can be applied in a radical prostatectomy procedure, whereby, after prostatectomy, the stent enables the anastomosis reconstruction of the bladder neck and urethral stump, thereby restoring the continuous conduction structure of the urinary tract.

[0055] The methods for forming medical stents include:

[0056] S1, multiple first wires are interwoven at least partially along a first direction and multiple second wires are interwoven at least partially along a second direction to form a mesh, thereby obtaining a first blank;

[0057] S2, heat-set the first billet to obtain the second billet;

[0058] S3, fix the intersection of the first wire and the second wire to fix the first wire and the second wire, and obtain the third initial billet.

[0059] The molding method of this medical stent involves heat-setting the first blank before welding the cross nodes. This effectively stabilizes the overall mesh structure after weaving, eliminates weaving stress, and improves the dimensional stability and structural regularity of the stent. Finally, the cross nodes of the first and second wires are welded and fixed, which can prevent the weaving nodes from loosening, slipping, or misaligning. This significantly enhances the overall structural strength and connection reliability of the stent, and prevents the mesh structure from loosening and deforming during use. At the same time, the step-by-step molding process gradually optimizes the structural performance of the stent, taking into account both the flexible implantation characteristics of the stent and the structural stability for long-term use, effectively improving the finished product quality and clinical safety of the medical stent.

[0060] Meanwhile, step S1 involves weaving multiple wires together along the first and second directions to form a mesh-like first blank. This weaving structure provides the support with good overall flexibility, fit, and deformation adaptability, meeting the needs for adapting to the complex shapes of human body cavities.

[0061] In this embodiment, the wire diameter is 0.1mm-0.35mm. The operator can select the appropriate size according to their needs to meet the requirements of different scenarios. For example, in this embodiment, the wire diameter is 0.2mm.

[0062] Optionally, the mesh size in the first blank is 1mm-5mm. For example, the mesh size is 1mm, 2mm, 3mm, 4mm, or 5mm.

[0063] The weaving angle between the first and second directions is 30°-60°, and the number of cross nodes is lower than that of conventional stent structures. This helps to reduce the pressure of medical stents on tissues, reduces the contact area, fits the anatomical structure better, and accelerates degradation while meeting mechanical requirements, resulting in less material.

[0064] like Figure 2 As shown, in one embodiment, the medical stent includes a first support member 100, a second support member 200, and a connector 300. The first support member 100, the second support member 200, and the connector 300 can be formed by the molding method described above.

[0065] This medical stent employs a combined structural design of a first support member 100, a second support member 200, and a connector 300. The connector 300 enables reliable connection and relative positional limitation of the two sets of support members. It can flexibly adapt to deformation according to the actual shape of the bladder neck and urethral stump, dispersing the overall stress on the medical stent and reducing local stress concentration. This ensures the overall support strength and structural integrity of the medical stent while improving its bending flexibility and fit, reducing friction and irritation to human tissues after implantation. At the same time, the modular component layout facilitates optimization of the overall compression performance and expansion rebound effect of the medical stent, improving the convenience of implantation and clinical suitability.

[0066] After the first support member 100, the second support member 200, and the connector 300 are formed separately using the above-described forming method, they are connected during surgery to form a complete medical stent structure. This multi-structure connection method, through the heat-setting treatment of the first blank in step S2, effectively eliminates residual internal stresses such as torsion and tension generated during wire weaving, stabilizes the external dimensions and weaving pattern of each component, and avoids the stress unevenness, deformation, and warping problems that are common in single-piece woven stents. Simultaneously, the independent forming of each component allows for targeted optimization of the flexibility, support force, and mechanical properties of different parts, reducing assembly and splicing difficulty, and resulting in a more reasonable stress distribution at the connection points. This effectively improves the overall structural stability, deformation uniformity, and implantability of the stent, reducing tissue compression and structural loosening caused by stress concentration after implantation, and further enhancing the overall safety and durability of the medical stent.

[0067] The first blank is either a first support 100 or a second support 200, and the first support 100 and the second support 200 are separate structures. The separate structure helps to reduce the molding difficulty, and the first support 100 can also be set with different axial dimensions to adapt to the individual differences of different patients.

[0068] Furthermore, the first support 100, the second support 200, and the connector 300 are made of absorbable polymer materials, such as polydioxanone, polycaprolactone, and polylactic acid. Using the same material throughout the medical stent helps ensure the consistency of degradation rates for the first support 100, the second support 200, and the connector 300. This effectively avoids interfacial stress, uneven local degradation, and tissue irritation problems caused by inconsistent degradation cycles and rates when using multiple materials in combination. This improves the overall structural stability and implantation safety of the stent, while simplifying material selection and processing, reducing manufacturing costs, and better meeting the long-term needs of urological postoperative tissue repair.

[0069] In one embodiment, the step of heat-setting the first preform to obtain the second preform includes:

[0070] The first billet is heated at a first preset temperature for a first preset time.

[0071] The above forming method can completely eliminate residual internal stresses such as torsion, tension, and bending generated during the cross-weaving process of the wires, allowing the overall structure of the stent braided mesh to fully relax and solidify, unifying and standardizing the overall shape and dimensional accuracy, avoiding later deformation, warping, and shrinkage problems caused by localized residual stress, uniformly optimizing the microstructure and mechanical state of the wire material, ensuring the consistency of form and performance of each component of the first support 100, the second support 200, and the connector 300, improving the overall structural regularity and morphological stability of the braided blank, providing reliable structural protection for subsequent cross-node welding, component splicing and assembly, and deformation rebound and flexible support performance during stent implantation and use, effectively reducing the defect rate of finished products, and enhancing the overall structural reliability and clinical suitability of the modular medical stent.

[0072] The first preset temperature is 60℃-90℃; this temperature range can match the thermal properties of absorbable polymer materials. Within this temperature range, the first initial blank of the weaving is heated and shaped at a constant temperature, which can gently and fully release the residual internal stress generated during the torsion, stretching, and bending of the monofilament during weaving, so as to promote the overall relaxation and regularity of the mesh structure and accurately stabilize the shape and weaving form of each component.

[0073] Meanwhile, this temperature range falls within the low-temperature, moderate-heating range, which will not damage the molecular chain structure of the absorbable polymer or the inherent physicochemical properties of the substrate. This avoids material aging, embrittlement, decreased flexibility, or biocompatibility degradation caused by high temperatures, perfectly preserving the required bending flexibility and supporting mechanical properties of the stent. Uniform low-temperature heat setting conditions ensure consistent setting effects for the three components: the first support 100, the second support 200, and the connector 300. Combined with a design using the same material throughout, this further maintains the synchronicity of degradation rates for each component, eliminating local performance inconsistencies and degradation imbalances caused by differences in heat processing. It also reduces interfacial stress and the risk of postoperative tissue irritation, improves the stability of the node structure and the precision of subsequent welding and assembly, and reduces finished product defects. While meeting the requirements of the braided blank setting process and simplifying production control, it comprehensively ensures the structural stability, safety of use, and postoperative tissue repair compatibility of the modular absorbable medical stent.

[0074] Specifically, the first preset temperature can be selected according to the specific material or the twisting, stretching or bending that occurs during the weaving process. This embodiment does not limit this.

[0075] For example, the first preset temperature can be any temperature among 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C.

[0076] In one embodiment, the first preset duration is 5 min to 20 min. This first preset duration can be synergistically adapted to the setting temperature. The short duration range can adapt to the stress relaxation characteristics of absorbable polymers such as polylactic acid, polycaprolactone, and polydioxanone. While effectively eliminating the residual internal stress caused by torsion, tension, and bending generated by monofilament weaving, it allows the first initial fabric mesh structure to be fully relaxed and regularized, stabilizing the overall size and weaving morphology.

[0077] Meanwhile, the first preset duration is reasonable and controllable. It can avoid incomplete stress release and insufficient shaping effect due to excessively short heating time, thus preventing deformation and warping of components later. It can also prevent thermal damage to the molecular chains of absorbable materials, material aging, decreased flexibility, and changes in degradation performance caused by excessively long heating time. This ensures the uniformity of mechanical properties, biocompatibility, and degradation rate of each support and connector. The uniform and appropriate heating duration can ensure the uniform shaping quality of the separate components, improve the precision of subsequent node welding and assembly, reduce the defect rate of finished products, and adapt to the pace of large-scale production. While strengthening the overall structural stability and implantation safety of the stent, it meets the manufacturing process requirements and clinical application standards of absorbable medical stents.

[0078] Optionally, the first preset duration is any one of 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, or 20 min, or any duration in between.

[0079] For example, in this embodiment, the first preset temperature for heat setting in step S2 is 70°C, and the first preset duration is 10 minutes.

[0080] In one embodiment, step S1 can be performed on a mold to ensure the stability of the medical stent's braided shape. Optionally, the mold includes a body and multiple limiting posts inserted into the body, the multiple limiting posts being arranged in an array to limit the braiding process of the first and second monofilaments. During braiding, the first and second monofilaments are cross-braided under the limiting of the multiple limiting posts to form a mesh shape of the first support 100, the second support 200, and the connector 300.

[0081] Furthermore, step S2 involves heat-setting the first blank as a whole on a mold, thereby ensuring that the first blank is directly heat-set after being woven into a mesh shape, so as to ensure that the shape of the second blank is similar to that of the first blank and thus improve structural stability.

[0082] Optionally, the limiting post is telescopically fitted to the body. After all the above steps S1-S3 are completed, the limiting post retracts, allowing the third blank to be removed from the mold.

[0083] In one embodiment, the step of fixing the intersection of the first wire and the second wire to fix the first wire and the second wire and obtain the third preliminary blank includes:

[0084] Fixed intersection node.

[0085] After the first preform has undergone heat setting in step S2 to release stress and stabilize its shape, the intersection nodes of the first and second wires are welded and fixed. This allows the interlacing points of the first and second wires to form an integrated connection structure, effectively limiting the relative slippage, misalignment, and loosening between adjacent monofilaments, locking the arrangement of the mesh weave structure, and significantly improving the overall structural density and mechanical integrity of the third preform. Combining the properties of absorbable polymer materials and the modular component design, the node welding can evenly distribute the stress on the scaffold, improve the problem of local stress concentration, maintain the structural integrity of the first support 100, the second support 200, and the connector 300, and prevent the woven mesh from loosening and deforming during compression, expansion, and implantation. At the same time, it enhances the dimensional stability and molding consistency of each component, providing structural support for subsequent scaffold assembly and use, in vivo deformation adaptation, and stable degradation.

[0086] The method for fixing the intersection node includes one of the following methods:

[0087] All intersections were heat-welded;

[0088] Ultrasonic welding of all intersecting joints;

[0089] The cross joints are heat-welded, and the remaining cross joints are ultrasonically welded.

[0090] All three methods are suitable for the bonding properties of absorbable polymers such as polylactic acid, polycaprolactone, and polydioxanone.

[0091] Among them, thermal welding can use heat energy to melt and bond the polymer materials at the cross joint. By locally melting the intersection, a rapid shaping connection can be achieved, and the position of the intersection can be fixed.

[0092] Ultrasonic welding relies on high-frequency vibration to generate local melting and frictional heat to complete the seamless fusion. The heat-affected zone of ultrasonic welding is small, which is beneficial to improve the strength of the cross-node position after welding, thereby improving the structural stability of the first support 100, the second support 200 and the connector 300 after processing.

[0093] Among them, the connector 300 may have some nodes using the above welding method and some nodes being movably connected, thereby maintaining the connector 300 having movable displacement in the axial and radial directions.

[0094] The combined use of thermal welding and ultrasonic welding can balance welding efficiency and uniformity of joint connections.

[0095] The above-mentioned multiple welding methods offer flexible options, effectively locking the interlacing position of the first and second wires, reducing the risk of slippage, loosening, and cracking of the braided nodes, strengthening the overall structural strength and dimensional stability of the third blank, and precisely controlling the welding heat input range to avoid large-scale high-temperature damage to the flexibility, biocompatibility, and degradation performance of the stent substrate. This ensures uniform mechanical properties of each component, reduces residual welding stress, improves the expansion and rebound capacity and bending resistance of the mesh stent, effectively adapts to the subsequent assembly of split-type absorbable medical stents and the deformation requirements of complex cavities in the body, reduces the risk of structural failure after implantation, and ensures product processing yield and clinical safety.

[0096] Furthermore, the steps of heat-welding all intersections include:

[0097] The heating tool, heated to a second preset temperature, is used to contact the intersection node for a second preset duration; the second preset temperature is 120℃-180℃; and the second preset duration is 0.5s-2s.

[0098] This step involves using a heating tool heated to 120℃-180℃ to briefly contact the cross-node for 0.5s-2s to achieve targeted thermal welding. Relying on the processing mode of instantaneous high temperature and short contact, it can accurately and rapidly melt and bond the cross-nodes of absorbable polymer materials. The short-term high temperature effect is concentrated only in a very small area of ​​the node. The heat input is concentrated and the action time is extremely short, which can quickly complete the node welding and shaping, lock the relative position of the wires, and effectively prevent the braided nodes from slipping and loosening.

[0099] Meanwhile, the strictly limited temperature range and short contact time can flexibly adapt to the melting characteristics of different absorbable materials such as polylactic acid, polycaprolactone, and polydioxanone, allowing for on-demand control of the melting degree while significantly reducing the heat-affected zone. This prevents heat diffusion from damaging the surrounding wire matrix structure, maximizing the preservation of the original flexibility, mechanical properties, and biodegradability of the support substrate, and preventing material aging, embrittlement, and degradation rate changes caused by prolonged high temperatures. Instantaneous short-term heating can effectively suppress the generation of welding residual stress, ensuring uniform and firm joint welding, improving the connection strength and consistency of individual joints, and adapting to the separate forming processing requirements of the first support component 100, the second support component 200, and the connector 300. It balances welding processing efficiency and forming accuracy, avoiding dimensional deformation and performance inconsistencies caused by large-area hot processing, and further optimizing the overall support structure's structural stability and bending resistance.

[0100] For example, the second preset temperature is any one of 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, or any temperature in between.

[0101] For example, the second preset duration is any one of 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1.0s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s, 1.6s, 1.7s, 1.8s, 1.9s, or 2s, or any duration in between.

[0102] Furthermore, when the heating tool comes into contact with the cross node, the heating tool and the cross node are pressed together with a first preset pressure. This promotes the tight adhesion of the first and second wires during the material melting stage of the cross node, compresses the wire gaps, improves the fusion tightness and uniformity of the molten interface, and avoids incomplete soldering and desoldering. At the same time, the pressure can assist the rapid spread and penetration of the molten polymer material, enhance the bonding strength and structural integrity of the cross node, and prevent the node from cracking or loosening under stress.

[0103] In one embodiment, the process parameters for the ultrasonic welding of all intersecting nodes include a second preset pressure, a third preset duration, and a preset frequency; the second preset pressure is 0.1 MPa-0.5 MPa; the third preset duration is 0.1 s-1 s; and the preset frequency is 20 kHz-40 kHz.

[0104] In this ultrasonic welding process parameter specification, appropriate pressure ensures a tight fit between the first and second wires at the intersection, providing stable contact conditions for high-frequency vibration welding. This avoids insufficient pressure leading to weak bonding or excessive pressure causing wire deformation and structural damage. Simultaneously, the shorter welding time enables instantaneous localized frictional heat generation and melting, significantly reducing the heat-affected zone and effectively mitigating the problems of molecular chain damage, performance degradation, and abnormal degradation rates in absorbable materials such as polylactic acid, polycaprolactone, and polydioxanone due to prolonged heating.

[0105] Meanwhile, a reasonable ultrasonic frequency can stably generate high-frequency micro-amplitude vibrations, rapidly generating frictional heat at the intersection to achieve seamless welding, improving the density and structural strength of the node connection, while reducing welding residual stress. This ensures uniform and consistent mechanical properties of the 300 welding nodes of each support and connector, balancing welding efficiency and processing precision, maintaining the overall flexibility and deformation resilience of the braided stent, effectively preventing node loosening and cracking, and further enhancing the structural stability, product consistency, and implantation safety of the split medical stent.

[0106] For example, the second preset pressure is any one of 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, or any pressure in between.

[0107] In one embodiment, step S3 of this embodiment uses hot welding of the cross joints, and the second preset welding temperature is 150°C, with a welding time of 1 second. At this time, the structural strength of the cross joint position of the third blank is 80% of the initial wire structural strength, that is, the hot welding process alone has little impact on the structural strength of the material, which is beneficial to ensuring the structural strength of the formed first support 100 and second support 200.

[0108] In one embodiment, step S3 employs a hybrid welding method combining thermal welding and ultrasonic welding. Specifically, in step S3, ultrasonic welding is used at the intersection of the first support member 100 and the second support member 200, while thermal welding is used at some intersections of the connector 300. Through this combined welding method, the overall structural strength of the medical stent obtained is more than 80% of the structural strength of the initial wire, meaning that the medical stent formed by this combined welding method has higher structural strength and lower cost.

[0109] The welding process includes the intersection of the first and second wires to fix them in place. After obtaining the third preliminary billet, the process also includes:

[0110] The third blank is deburred, cleaned and dried in sequence to obtain the first support 100, the second support 200 or the connector 300. The first support 100 and the second support 200 can be connected by the connector 300 to form a medical stent.

[0111] After the cross-node welding and shaping of the third initial blank is completed, deburring, cleaning, and drying are performed sequentially to obtain the first support component 100, the second support component 200, or the connector 300. This effectively removes burrs, flash, and local protrusions generated during welding and braiding, eliminates sharp structures, avoids scratching human tissue during implantation, and improves product safety. The cleaning process thoroughly removes residual impurities, dust, and trace processing residues, ensuring the surface cleanliness of the absorbable scaffold components, maintaining good biocompatibility of the material, and preventing adverse reactions such as postoperative inflammation and irritation caused by foreign bodies. The subsequent drying process completely removes residual moisture from the cleaning, preventing problems such as premature degradation, material deterioration, and performance decline of absorbable polymer materials due to long-term moisture exposure. It stabilizes the component dimensions and mechanical properties, further optimizes the surface finish and finished product appearance quality, and ensures the processing consistency and structural integrity of each component in the modular design. This provides a clean, orderly, and stable foundation for subsequent precise assembly, clinical implantation, and stable degradation in vivo.

[0112] Alternatively, deburring can be performed using hot air at a temperature of 80°C-100°C.

[0113] After completing the above steps, the molding method also includes sterilization and packaging processes.

[0114] The sterilization process utilizes ethylene oxide sterilization. Leveraging the low-temperature gas-phase sterilization properties of ethylene oxide, it allows for complete sterilization of each component of the scaffold under a mild, low-temperature environment. This sterilization method boasts excellent penetration, fully penetrating the pores of the woven mesh structure, wire intersections, and minute gaps to achieve thorough sterilization without dead angles, completely eliminating bacteria, spores, fungi, viruses, and other microorganisms. Simultaneously, the ethylene oxide sterilization process involves no high temperatures or strong radiation, preserving the molecular structure of absorbable polymers such as polylactic acid, polycaprolactone, and polydioxanone. This effectively avoids issues such as material aging, mechanical degradation, changes in degradation rates, and decreased biocompatibility, maximizing the preservation of the scaffold components' flexibility, structural strength, and stable degradation performance. After analysis, ethylene oxide residue is completely removed, eliminating sensitization and toxicological risks. This ensures the finished scaffold meets medical implant-grade sterility standards, effectively mitigating post-implantation infection risks and comprehensively improving the clinical safety and product compliance of the modular absorbable medical scaffold.

[0115] The packaging utilizes a flash-evaporation process with high-density polyethylene (HDPE) nonwoven fabric and aluminum foil bags. The HDPE nonwoven fabric, with its breathable yet sterile properties, allows for successful sterilization and residue removal via ethylene oxide gas penetration. The aluminum foil layer provides excellent oxygen barrier, moisture protection, light protection, and microbial barrier capabilities. This combination satisfies the ethylene oxide sterilization requirements for medical stents, avoiding incomplete sterilization and residue buildup caused by airtight packaging. It also effectively protects absorbable polymer materials, inhibiting moisture absorption, aging, and premature degradation. Furthermore, the clean, debris-free, robust, and reliably sealed packaging maintains the product's sterility over a long period, ensuring the stability of medical stent storage, safety during use, and long-term service performance.

[0116] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0117] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for forming a medical stent, characterized in that, The forming method for manufacturing medical stents includes: Multiple first wires are interwoven at least partially along a first direction and multiple second wires are interwoven at least partially along a second direction to form a mesh, thereby obtaining a first blank; The first preliminary billet is heat-set to obtain the second preliminary billet; Fix the intersection of the first wire and the second wire to secure the first wire and the second wire, and obtain the third initial blank.

2. The method for forming a medical stent according to claim 1, characterized in that, The step of heat-setting the first preliminary billet to obtain the second preliminary billet includes: The cross node is heated at a first preset temperature for a first preset duration.

3. The method for forming a medical stent according to claim 2, characterized in that, The first preset temperature is 60℃-90℃; And / or, the first preset duration is 5min-20min.

4. The method for forming a medical stent according to claim 1, characterized in that, The step of fixing the intersection of the first wire and the second wire to fix the first wire and the second wire and obtain the third preliminary blank includes: Fix the intersection node.

5. The method for forming a medical stent according to claim 4, characterized in that, The method for fixing the intersection node includes one of the following methods: All the aforementioned cross nodes were heat-welded; All the aforementioned cross nodes were ultrasonically welded; The cross joints are partially heat-welded, and the remaining cross joints are ultrasonically welded.

6. The method for forming a medical stent according to claim 5, characterized in that, The step of hot welding all the cross nodes includes: The heating tool, heated to a second preset temperature, is brought into contact with the intersection node for a second preset duration. The second preset temperature is 120℃-180℃; The second preset duration is 0.5s-2s.

7. The method for forming a medical stent according to claim 6, characterized in that, When the heating tool comes into contact with the intersection node, the heating tool and the intersection node abut against each other with a first preset pressure.

8. The method for forming a medical stent according to claim 5, characterized in that, The process parameters for all the cross-node steps in the ultrasonic welding include a second preset pressure, a third preset duration, and a preset frequency. The second preset pressure is 0.1 MPa - 0.5 MPa; The third preset duration is 0.1s-1s; The preset frequency is 20kHz-40kHz.

9. The method for forming a medical stent according to any one of claims 1-8, characterized in that, The first blank is a first support member (100) or a second support member (200), and the first support member (100) and the second support member (200) are separate structures.

10. The method for forming a medical stent according to any one of claims 1-8, characterized in that, The welding process includes fixing the first and second wires at their intersection points to obtain the third preliminary blank, and further includes: The third blank is deburred, cleaned and dried in sequence to obtain a first support (100), a second support (200) or a connector (300). The first support (100) and the second support (200) can be connected by the connector (300) to form the medical stent.

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