Ureteral stent and preparation method thereof

Abstract

The present invention relates to a ureteral stent and a preparation method thereof, comprising a degradable mesh tube body and a degradable support component, wherein the tube body is a double J-shaped structure, the support component comprises a coating, the support component is arranged on the tube body, and the tube body comprises J-shaped ends at both ends and a middle portion between the two J-shaped ends. The ureteral stent can provide good urine drainage and ureteral support effects when implanted in a patient's body, can be well fixed in the patient's kidney and bladder without displacement, and gradually degrades in the body as the patient's hydronephrosis and ureteral obstruction and stenosis are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a ureteral stent and a preparation method thereof. Background Art

[0002] Common urinary diseases such as stones, scars and tumors can cause ureteral stenosis and obstruction, so ureteral stents need to be placed to improve hydronephrosis, drain urine from the kidney-ureter-bladder system (KUB), and expand the ureteral passage to allow larger stones to be discharged from the urethra. In addition, doctors clinically place ureteral stents for urological surgeries such as ureteroscopy, lithotripsy, open surgery, pyelolithotomy, pyeloplasty and percutaneous nephrolithotomy to avoid damage to the ureter during surgery and protect the ureteral mucosa and epithelial cells.

[0003] Normally, the recovery time after ureteral surgery is about 1 to 2 months, but for patients with more serious conditions such as hydronephrosis and ureteral tumors, a ureteral stent needs to be placed for at least 4 to 6 months to allow the urethra to recover and improve hydronephrosis. Currently, common ureteral stents in clinical practice include metal ureteral stents and ureteral stents made of polymer materials, and these ureteral stents are non-degradable. Among them, metal ureteral stents have good mechanical properties, can provide relatively long-lasting radial support, and have excellent drainage effects, but if they are left in the ureter for a long time, urine salts will deposit on the surface of the metal stent, leading to the re-obstruction of the ureter. Moreover, the metal is hard in texture, and implantation in the ureter stimulates the patient's urethra, causing a strong foreign body sensation. In addition, metal stents are expensive, which increases the economic burden on patients, so the commercial use rate in the market is slowly decreasing. The main materials of polymer ureteral stents are polyethylene, polyurethane and silicone rubber. These materials are economical, environmentally friendly and easy to process. However, the surface of such ureteral stents is smooth, the friction is small, and they are prone to displacement. Moreover, when placed in the ureter, they are prone to cause inflammatory reactions in the urethra, as well as complications such as frequent urination and hematuria. Although these two types of ureteral stents can provide good urine drainage and ureteral support, various complications will appear one after another as the stents are left in place for a long time. After the ureteral condition recovers, the stents still need to be removed through a secondary open surgery, which brings additional pain and economic burden to patients.

[0004] With the development of materials science, degradable polymer materials are increasingly widely used in pharmaceutical, medical engineering materials, aerospace and other fields. Ureteral stents made of degradable materials not only have good flexibility and biocompatibility, but also provide good internal support and drainage of urine. Degradable polymer materials can be degraded into water and carbon dioxide and excreted from the body within a certain period of time, thereby solving a series of complications caused by long-term retention of the stent in the body, and at the same time eliminating the process of secondary surgery to remove the stent. The degradation cycle and mechanical properties of degradable ureteral stents are important factors affecting the use effect of ureteral stents.

[0005] For example, some degradable ureteral stents have a skeleton that is a mesh stent made of "W"-shaped polymer materials spliced ​​along the axial direction through connecting rods, and this structure is repeated radially to form a complete stent. The disadvantage of this stent is that it is only a long straight rod without a positioning structure. When placed in the patient's ureter, bladder and kidney, it cannot play an anchoring role, and the stent often shifts and damages the urethra. In addition, the stent surface pores of this splicing structure are large, and leakage occurs when draining urine, so it is difficult to drain urine from the kidney to the ureter. Other non-degradable ureteral stents are composed of a double J-shaped ureteral stent and an outer spiral tube. The outer spiral tube is wound around the outer circle J-shaped skeleton. This type of ureteral stent can provide a good urine drainage effect, but the winding of the two spiral tubes will increase the overall diameter and wall thickness of the stent tube, thereby irritating the patient's urethra and easily damaging the urethral mucosa. At the same time, the winding causes the stent surface to be uneven, which in turn causes discomfort in the patient's urethra and causes urinary tract related inflammation. There are also some degradable ureteral stents, which are formed by weaving and are made of tubes with a mesh surface. This type of ureteral stent has a simple structure and is easy to process, but its radial support force is average and there is a possibility of collapse, which can cause obstruction of the patient's urinary system and reduce the expected effect of stent placement. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a ureteral stent and a preparation method thereof, which can provide good urine drainage and support effects, and can be better fixed in the patient's body without displacement, and will not cause discomfort to the patient. It has little stimulation to the patient's urinary system, and can reduce the generation of small fragments during the degradation process, reducing the risk of local inflammation and scratching epithelial cells and mucosal tissues.

[0007] To achieve the above-mentioned purpose or other purposes, the present invention provides a ureteral stent, including a degradable mesh tube body and a degradable support component, wherein the tube body is a double J-shaped structure, the support component includes a coating, and the support component is arranged on the tube body; the tube body includes J-shaped end portions located at both ends and a middle portion located between the two J-shaped end portions.

[0008] Optionally, the support component is arranged at the two J-shaped ends of the tube body, and / or the support component is arranged on the middle part of the tube body.

[0009] Optionally, the supporting component covers a portion of the surface of the tube body along the circumferential direction.

[0010] Optionally, the arc of the supporting component in the circumferential direction is π / 6 to π.

[0011] Optionally, the degradation rate of the supporting component is lower than the degradation rate of the tube body.

[0012] Optionally, the degradation time of the tube body is 6 to 12 months, and the degradation time of the support component is 6 to 36 months.

[0013] Optionally, the material of the tube body is a polymer compound, and the weight average molecular weight of the tube body is 100,000 to 300,000 g / mol, and / or the material of the support component is a polymer compound, and the weight average molecular weight of the support component is 300,000 to 800,000 g / mol.

[0014] Optionally, the tube body is woven from degradable fibers, the elongation at break of the degradable fibers is greater than 20%, and the tensile strength of the degradable fibers is greater than 1 cN / dtex.

[0015] Optionally, the diameter of the degradable fiber is 0.05 mm to 0.15 mm.

[0016] Optionally, the material of the tube body is selected from one or a combination of the following materials:

[0017] Polylactic acid, L-lactic acid, D-lactic acid, polyglycolic acid, poly-ε-caprolactone, polyethylene glycol, polyphthalamide, polyethylene oxide and polyvinyl alcohol, and a copolymer formed by at least two of lactic acid, L-lactic acid, D-lactic acid, glycolic acid, ε-caprolactone, ethylene glycol, phthalamide, ethylene oxide and vinyl alcohol, and / or the material of the supporting member is selected from one or more of the following materials:

[0018] Polylactic acid, L-lactic acid, D-lactic acid, polyglycolic acid, poly-ε-caprolactone, polyethylene glycol, polyphthalamide, polyethylene oxide and polyvinyl alcohol, and copolymers formed by at least two of lactic acid, L-lactic acid, D-lactic acid, glycolic acid, ε-caprolactone, ethylene glycol, phthalamide, ethylene oxide and vinyl alcohol.

[0019] Optionally, the thickness of the coating is 0.05 mm to 0.15 mm.

[0020] Optionally, the tensile elastic modulus of the supporting component is higher than 1 GPa.

[0021] Optionally, the middle portion has an axial length of 120 mm to 300 mm and an outer diameter of 1.4 mm to 2.6 mm.

[0022] Optionally, the tube body is woven from a degradable material, the woven mesh of the tube body has an angle, the angle is an acute angle, the acute angle is 60° to 80°, and the number of weaving intersection points of the tube body along its circumferential direction is 8 to 32.

[0023] Optionally, the support component covers the inner surface or the outer surface of the tube body, or the support component is embedded in the tube body while covering the surface of the support component.

[0024] To achieve the above purpose or other purposes, the present invention provides a method for preparing a ureteral stent, comprising:

[0025] A mesh tube body is prepared by using a degradable polymer material, and the tube body is heat-formed into a double J shape at a predetermined temperature;

[0026] A film-shaped support component is prepared by using a degradable polymer material, and the support component is arranged on the tube body.

[0027] Optionally, the tube body is woven from degradable fibers, and the tube body is heat-formed into a double J shape at a temperature of 50° C. to 80° C.

[0028] Optionally, the supporting component is arranged on the tube body in the following manners:

[0029] Obtaining a coating through a blow molding process, and nesting the coating on the tube body, and after the nesting, heat-setting the coating together with the tube body into a double J shape, or, before the nesting, heat-setting the coating and the tube body into a double J shape respectively in advance;

[0030] Alternatively, the supporting component is arranged on the tube body in the following manners:

[0031] Forming a coating on the outer surface of the tube body by an electrospinning process, and after electrospinning, heat-setting the coating and the tube body together into a double J shape, or, before electrospinning, heat-setting the tube body into a double J shape in advance, so that the coating generated by electrospinning is also in a double J shape;

[0032] Alternatively, the supporting component is arranged on the tube body in the following manners:

[0033] A degradable polymer material is sprayed on the outer surface of the tube body to form a coating, and after spraying, the coating and the tube body are heat-formed together into a double J shape, or, before spraying, the tube body is heat-formed into a double J shape in advance so that the coating generated by spraying is also in a double J shape.

[0034] After being implanted in the patient's body, the above-mentioned ureteral stent can provide good urine drainage and ureteral support effects, can be well fixed in the patient's kidney and bladder without displacement, and gradually degrade in the body as the patient's hydronephrosis and ureteral obstruction and stenosis are improved. The patient can avoid long-term retention of the stent in the body due to forgetfulness, and can also avoid the need for surgery to remove it again like metal (nickel-titanium alloy, stainless steel, etc.) and ordinary polymer stents (such as polyurethane, polyethylene, etc.), reducing the patient's economic expenditure and pain, greatly improving the treatment effect, and improving the patient's quality of life.

[0035] The above-mentioned ureteral stent has good radial support, toughness and flexibility, which can make it run along the anatomical structure of the urethra and cause less stimulation when left in the patient's urinary system. In addition, the support component can assist in supporting the middle part and / or the two ends of the J-shaped tube of the braided or cut type, thereby improving the radial support and anchoring performance of the ureteral stent, improving the drainage and support effect of the ureteral stent, and preventing the occurrence of problems such as stent displacement. Moreover, the ureteral stent has a simple structure and is easy to process and shape.

[0036] The support component of the above-mentioned ureteral stent preferably covers only a part of the surface of the tube body along the circumferential direction, such as the arc of the support component in the circumferential direction is π / 6 to π. With this structure, the coverage rate of the coating is reduced, which ensures that the support component can be fully degraded on the one hand, and reduces the generation of small fragments during the degradation process on the other hand, thereby reducing the possibility of local inflammation and scratching of ureteral epithelial cells and mucosal tissues.

[0037] The tube body of the above-mentioned ureteral stent is a braided structure, and the number of braiding interlaced points is preferably 8 to 32, so that it has good flexibility and supporting strength, effectively passes through the narrow and obstructed parts of the patient's ureter, and better drains urine and stretches the ureter.

[0038] The degradation rate of the tube body of the above-mentioned ureteral stent is higher than that of the supporting component, so that the tube body is degraded first. In this way, when the degradation product of the tube body is too large, the urethra can be opened through the lumen formed by the supporting component to discharge the ureter into the bladder, avoiding the occurrence of re-stenosis at the narrow part. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0040] Figure 1 is a schematic structural diagram of a ureteral stent in a preferred embodiment of the present invention;

[0041] Figure 2 It is a partial view of a ureteral stent in a preferred embodiment of the present invention;

[0042] Figure 3 A partial view of a tube body in a preferred embodiment of the present invention;

[0043] Figure 4 for Figure 3 A partial enlarged view of the tube body at position A shown;

[0044] Figure 5 It is a schematic structural diagram of a sheet-like coating in a preferred embodiment of the present invention;

[0045] Figure 6 For the general Figure 5 The sheet-like film is heat-formed into a schematic diagram of the structure of a double J-shaped support member.

[0046] in:

[0047] 1-tube body; 2-support component; 3-length of the middle part; 11-J-shaped end; 12-middle part; 4-sheet membrane material; β-weaving grid angle.

[0048] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION

[0049] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the present embodiment only illustrate the basic concept of the present invention in a schematic manner, and the drawings only show the components related to the present invention rather than drawing according to the number, shape and size of the components in the actual implementation. The type, quantity and proportion of each component in the actual implementation can be a random change, and the component layout type may also be more complicated.

[0050] In addition, each embodiment of the following description has one or more technical features, but this does not mean that the user of the present invention must implement all the technical features in any embodiment at the same time, or can only implement part or all of the technical features in different embodiments separately. In other words, under the premise that implementation is possible, those skilled in the art can selectively implement part or all of the technical features in any embodiment according to the disclosure of the present invention and according to the design specifications or implementation requirements, or selectively implement a combination of part or all of the technical features in multiple embodiments, thereby increasing the flexibility of the implementation of the present invention.

[0051] As used in this specification, the singular forms "a", "an", and "the" include plural objects, unless the content clearly indicates otherwise. As used in this specification, the meaning of "plurality" generally includes two or more, unless the content clearly indicates otherwise. As used in this specification, the term "or" is generally used in a sense including "and / or", unless the content clearly indicates otherwise. The term "axial" generally refers to the direction parallel to the axis of the stent graft, and "radial" generally refers to the direction perpendicular to the axial direction and pointing to the axis. It should also be understood that the present invention repeats reference numbers and / or letters in various embodiments. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or configurations discussed. It will also be understood that when an element is referred to as "connected" to another element, it can be directly connected to another element, or there can be one or more intermediate elements.

[0052] The ureteral stent of the present invention is further described below in conjunction with the accompanying drawings and preferred embodiments.

[0053] like Figure 1 and Figure 2 As shown, this embodiment provides a biodegradable ureteral stent, including a degradable mesh tube body 1 and a degradable support component 2. The materials of the tube body 1 and the support component 2 may be the same or different. Among them, the tube body 1 is configured as a double J-shaped structure, specifically including J-shaped ends 11 at both ends and a middle part 12 located between the two J-shaped ends 11, and the curling directions of the two J-shaped ends 11 are opposite, so that one J-shaped end 11 is fixed in the kidney and the other J-shaped end 11 is fixed in the bladder. The present invention does not limit the curling size of each J-shaped end 11, and it can be curled 360° or less than 360°, as long as a hook-shaped structure is formed to achieve the anchoring effect. In addition, the tube body 1 is usually of uniform diameter.

[0054] The material of the tube body 1 is a biodegradable polymer material (polymer compound), for example, one or more combinations of the following materials can be selected:

[0055] Polylactic acid (PLA), L-lactic acid (PLLA), D-lactic acid (PDLA), polyglycolic acid (PGA), poly-ε-caprolactone (PCL), polyethylene glycol (PEG), polyphthalamide (PPA), polyethylene oxide (PEO) and polyvinyl alcohol (PVA); and copolymers formed by at least two of lactic acid, L-lactic acid, D-lactic acid, glycolic acid, ε-caprolactone, ethylene glycol, phthalamide, ethylene oxide and vinyl alcohol.

[0056] The tube body 1 can be a braided mesh tube or a cut mesh tube, preferably a braided mesh tube. Because the braided mesh tube has good flexibility, it can reduce the irritation to the organ part. Preferably, the tube body 1 is woven from biodegradable fibers, and more preferably, the elongation at break of the biodegradable fibers used to prepare the tube body 1 is greater than 20%, and the tensile strength is greater than 1 cN / dtex (decine / dtex). Degradable fibers with high elongation at break have good toughness and can improve the overall flexibility of the stent. Degradable fibers with high tensile strength can reduce problems such as brittle fracture during the weaving process. Preferably, the diameter of the biodegradable fibers used to prepare the tube body 1 is 0.05 to 0.15 mm. It should be understood that fiber refers to a substance composed of continuous or discontinuous filaments; coating refers to a flat soft sheet composed of fibers through crossing, entanglement or connection.

[0057] The material of the supporting member 2 is a biodegradable polymer material (polymer compound), for example, one or more combinations of the following materials can be selected:

[0058] Polylactic acid (PLA), L-lactic acid (PLLA), D-lactic acid (PDLA), polyglycolic acid (PGA), poly-ε-caprolactone (PCL), polyethylene glycol (PEG), polyphthalamide (PPA), polyethylene oxide (PEO) and polyvinyl alcohol (PVA); and copolymers formed by at least two of lactic acid, L-lactic acid, D-lactic acid, glycolic acid, ε-caprolactone, ethylene glycol, phthalamide, ethylene oxide and vinyl alcohol.

[0059] Preferably, the material of the tube body 1 and the supporting component 2 may also be selected from racemic polylactic acid (PDLLA).

[0060] It should be noted that the degradable fiber lactide-glycolide copolymer (PLGA) is composed of 80% lactide (LA) and 20% glycolide (GA) by weight. Under normal circumstances, it will be completely degraded and excreted from the body in 1-2 months, which meets the use requirements of ureteral stents. PLA has good toughness and better mechanical strength than PGA, but it takes a long time to degrade. PGA has good hydrophilicity and a short degradation cycle. Through the copolymerization of LA and GA, on the one hand, the degradation cycle of PLA is improved, and on the other hand, the strength of PGA is improved. In addition, PLLA and PLGA have good biocompatibility and biodegradability. PLLA and PCL have good toughness and good tensile strength. PLA is widely used in artificial prostheses, biomedical materials, etc. due to its good performance, and the degradation products can be metabolized and excreted from the body. L-polylactic acid can be copolymerized with many monomers, such as glycolide, caprolactone, etc., to obtain the material performance materials required for production and processing. PLCL is obtained by copolymerization of caprolactone and L-lactic acid. PCL is a biodegradable polymer material with good flexibility and good biodegradability. The copolymerization of caprolactone and L-lactic acid not only improves the strength and toughness of the material, but also shortens the degradation time accordingly. PLGC is obtained by copolymerization of L-lactic acid, glycolide and caprolactone. This material has good toughness and high strength, and the degradation period is 2-3 months.

[0061] The support component 2 includes a coating, and the thickness of the coating is relatively small. Preferably, the thickness of the coating in the support component 2 is 0.05 mm to 0.15 mm. The use of the coating can avoid increasing the diameter and thickness of the ureteral stent, thereby avoiding irritation to the patient's urethra and damage to the urethral mucosa. At the same time, it will not cause unevenness on the surface of the skeleton, avoid causing discomfort to the patient's urethra, and thus avoid causing urinary tract related inflammation.

[0062] In actual use, the support component 2 is arranged on the tube body 1 and covers the surface of the tube body 1, such as covering the inner surface or the outer surface, or is also embedded in the tube body 1 at the same time. Further, the support component 2 can be arranged at the two J-shaped ends 11 and / or the middle part 12 of the tube body 1, so as to assist in supporting the two J-shaped ends 11 and / or the middle part 12 of the tube body 1 through the coating, ensure the radial support performance and anchoring performance of the ureteral stent, improve the drainage and support effect of the ureteral stent, and prevent the occurrence of problems such as stent displacement. Here, the stability of the J-shape of the tube body is maintained by coating, the anchoring performance is guaranteed, and at the same time, the coating is used to assist in increasing the radial support force and ensure the radial support strength, which effectively improves the anchoring force and support force of the biodegradable ureteral stent.

[0063] Moreover, the ureteral stent of the present invention can gradually degrade in the body as the patient's hydronephrosis and ureteral obstruction and stenosis are improved, which can avoid the stent being retained in the body for a long time, and can also avoid the need for surgery to remove it again, reducing the patient's economic expenditure and pain, greatly improving the treatment effect, and improving the patient's quality of life. The ureteral stent of the present invention also has good toughness and flexibility, which can make it run along the anatomical structure of the urethra, and will produce less stimulation when retained in the patient's urinary system. Moreover, the ureteral stent of the present invention not only has good radial supporting force, can fully expand the narrow part of the urethra and drain urine, but also the stent degrades evenly and can be completely degraded, and no residual degradation fragments of the stent will be left, thereby avoiding the inflammatory stimulation and scratching of the urethral mucosa caused by insufficient stent degradation in the past.

[0064] In this embodiment, the entire length of the tube body 1 along the axial direction is assisted by the coating, and the radial support effect is better. It should be known that the support component 2 can be covered on the inner surface, outer surface or embedded in the tube body 1. Here, the so-called support component 2 embedded in the tube body 1 means that the support component 2 can also include a degradable suture, which penetrates into and out of the tube body 1 to form a staggered suture. Preferably, the suture is made of degradable fiber, so that the coating is sutured on the tube body 1 through the suture, and at this time, the suture is embedded in the tube body 1. In other words, when the coating is formed by the electrospinning process, in the process of fiber deposition on the tube body 1, part of the fiber is deposited in the grid of the tube body 1 (i.e., embedded in the tube body 1), and part of the fiber is deposited on the braided wire of the tube body 1 (covered on the surface of the tube body 1). The support component 2 of the present invention is connected to the tube body 1 and will not fall off, and the connection method of the support component 2 and the tube body 1 is not limited, for example, it can be connected by suturing, gluing, hot pressing, etc.

[0065] Further preferably, the degradation rate of the support component 2 is lower than the degradation rate of the tube body 1, so that the fine degradation products of the tube body 1 can be discharged from the body through the lumen formed by the support component 2, and the ureteral obstruction will not be caused by excessive degradation products. Preferably, the degradation time of the tube body 1 is 6 months to 12 months, and the degradation time of the support component 2 is 6 months to 36 months. Here, the degradation time refers to the time from the beginning of degradation to the completion of degradation after the ureteral stent is implanted in the body.

[0066] Preferably, the material of the tube body 1 is a polymer compound, and the weight average molecular weight of the tube body 1 is a polymer of 100,000 to 300,000 g / mol, and the material of the support component 2 is a polymer compound, and the weight average molecular weight of the support component 2 is a polymer of 300,000 to 800,000 g / mol. If the weight average molecular weight is small, the mechanical strength is insufficient, and if the molecular weight is too large, the degradation time is too long. Therefore, the present invention selects a tube body 1 and a support component 2 with a suitable weight average molecular weight to ensure mechanical properties on the one hand and control the degradation rate on the other.

[0067] Further preferably, the support component 2 only covers a portion of the surface of the tube body 1 along the circumferential direction, that is, the tube body 1 is not covered on the entire circumference, so as to reduce the coverage rate of the coating, on the one hand to ensure that the support component 2 can be fully degraded, and on the other hand to reduce the generation of small fragments during the degradation process, thereby reducing the possibility of local inflammation and scratching ureteral epithelial cells and mucosal tissues. More preferably, the circumferential curvature of the support component 2 is π / 6~π, and the curvature within this range can reduce degradation products while ensuring sufficient radial support strength. Because a smaller curvature cannot provide sufficient support strength, a larger curvature leads to excessive degradation products, causing complications such as inflammatory reactions.

[0068] Furthermore, the tensile elastic modulus of the support component 2 is preferably higher than 1 GPa. A coating with a high elastic modulus can improve the overall support performance of the ureteral stent.

[0069] Furthermore, the axial length 3 of the middle portion 12 of the tube body 1 is preferably 120 mm to 300 mm, and the outer diameter is preferably 4.7F to 8F (i.e., 1.4 mm to 2.6 mm). With such a structure, the ureteral stent is suitable for patients with ureteral stenosis and obstruction before and after ureteral-related surgery with a ureteral lumen of "4.7F to 8F". It should be understood that the distance between the arc starting point of one J-shaped end 11 and the arc starting point of another J-shaped end 11 is the axial length 3 of the middle portion 12, wherein the arc starting point can be understood as the tangent point where the J-shaped end 11 and the middle portion 12 are tangent.

[0070] Preferably, the curling angle of the J-shaped end 11 at both ends of the tube body 1 is 360° or close to 360° to enhance the anchoring performance. Considering that a too large circle shape may cause discomfort to the patient, while a too small circle shape may reduce the anchoring force, for this reason, the outer diameter D of the J-shaped end 11 is preferably 15mm to 22mm. Furthermore, in order to reduce the stimulation and damage to the internal tissue after the implantation of the stent, the curled shape is preferably an arc. In addition, the vertical distance h from the free end of the J-shaped end 11 to the middle part 12 is preferably 6mm to 10mm to further reduce the discomfort caused to the patient. Because the J-shaped end 11 is placed in the kidney and bladder to play an anchoring role, the J-shaped end 11 that is too large or too small will cause discomfort to the patient's kidney and bladder.

[0071] Further Figure 3 and Figure 4 As shown, the woven mesh has an angle β, which is an acute angle. Considering that the size of the angle β of the woven mesh will affect the surface porosity of the stent, if the angle β of the woven mesh is too small, the surface pores will be larger, reducing the mechanical strength of the stent, and leakage will occur when draining urine; if the angle β of the woven mesh is too large, it will also reduce the flexibility of the skeleton and affect the formation of the "J"-shaped structure at both ends of the stent in the later stage. For this reason, the angle β of the woven mesh of the tube body 1 is preferably 60° to 80°. Here, the angle β of the woven mesh refers to the angle between two or two interlaced wires. Preferably, the number of weaving interlacing points of the tube body 1 along its circumferential direction is 8 to 32, and further, the number of woven strands along the circumferential direction (i.e., the number of thread ends along the circumferential direction) can be 25 strands, 30 strands or 35 strands. A large number of braiding interlaced points may easily lead to a decrease in the flexibility of the tube body, thereby affecting the delivery of the ureteral stent during surgery; a small number of braiding interlaced points may easily lead to insufficient mechanical strength of the tube body 1 and fail to provide sufficient radial support. Furthermore, in order to enhance the stability of the "J"-shaped areas at both ends, preferably, after the tube body 1 is braided and formed, it is heat-formed into a double J shape at a temperature of 50°C to 80°C. Heat setting helps to improve the stability of the "J"-shaped areas at both ends of the tube body 1 and enhance the anchoring performance.

[0072] The present invention does not limit the molding method of the support component 2. Figure 5 As shown, the sheet film material 4 can be prepared by a blow molding process, and then the sheet film material 4 is nested on the tube body 1, and after the nesting, the film material 4 and the tube body 1 are heat-set together into a double J shape, or before the nesting, the film material 4 and the tube body 1 are heat-set into a double J shape respectively, and then the two are nested after heat setting. Figure 5 As shown, a sheet-like film material 4 is obtained, and then Figure 6As shown, the sheet film material 4 is bent and then heat-set into the desired double J shape to obtain a film-shaped support component 2, and then the double J-shaped support component 2 is nested on the tube body 1. In other embodiments, a fiber-shaped film is deposited on the tube body 1 by an electrospinning process, and after electrospinning, the film and the tube body 1 are heat-set together into a double J shape, or, before electrospinning, the tube body 1 is heat-set in advance into a double J shape, so that the film generated by electrospinning directly forms a double J shape. In other embodiments, the degradable material is directly sprayed on the outer surface of the tube body 1 to form a film, and after spraying, the film and the tube body 1 are heat-set together into a double J shape, or, before spraying, the tube body 1 is heat-set in advance into a double J shape, so that the film generated by spraying is directly formed into a double J shape.

[0073] Next, the ureteral stent of the present invention is further described with respect to the prepared ureteral stent in combination with experimental data and experimental results, so as to further highlight the characteristics and features of the above-mentioned embodiment.

[0074] Example 1

[0075] First, a double J-shaped coating is obtained by heat setting, and the coating is nested inside the tube body 1, and the outer surface of the coating is closely fitted with the inner surface of the tube body 1, so that a ureteral stent can be obtained. The tube body 1 of the ureteral stent is woven and formed, so that the ureteral stent has good flexibility, and the J-shaped ends play a good anchoring role in the kidney and bladder.

[0076] Specifically, the tube body 1 is made of 32 polylactide-glycolide-caprolactone (PLGC) degradable fibers (weight average molecular weight of 200,000 g / mol, degradation period of 8 months) with a diameter of 0.1 mm, which are interlaced and woven to form a dense tubular structure, and then heat-set into a double J-shaped structure. In addition, the number of weaving intersections along the circumferential direction of the tube body 1 is set to 16, and the angle β of the weaving grid is 70°. In addition, the axial length 3 of the middle part 12 of the tube body 1 is 220 mm, the J-shaped end portions 11 at both ends are circles with an outer diameter D of 18 mm, and the vertical distance h between the free end of the J-shaped end portion 11 of the tube body 1 and the middle part 12 is 8 mm. In addition, the coating is formed by blow molding of dextrorotatory polylactic acid (PDLA) (weight average molecular weight of 500,000 mol, degradation period of 18 months) to have a thickness of 0.1 mm and a curvature of π / 6, and is heat-set into a double J-shaped structure under heating conditions of 80°C and 60 minutes.

[0077] The ureteral stent prepared in this embodiment begins to degrade 8 months after implantation in the body. It has a good urine drainage function, can provide good mechanical support strength, and improve urinary tract stenosis and obstruction. Specifically, the ureteral stent is implanted in a simulated urinary system, the simulated ureter diameter is 2.5 mm, artificial simulated urine (Artificial Urine Solution, AUS), buffer (pH = 6.0 ± 0.5) is selected as the simulated body fluid, and the rotation speed is 65 revolutions per minute in a constant temperature shaker, and the ambient temperature is set to 37 ° C for a simulated degradation experiment. The test results of the in vitro degradation simulation experiment show that the radial support force of the stent is 120 kPa at 6 months, the skeleton structure has not collapsed, and no obvious stent fragments are found during the degradation process. The simulated urinary system has a normal drainage function. The "J-shaped" parts at both ends of the stent are anchored in the area simulating the kidney and bladder, and no phenomena such as falling off and displacement occur.

[0078] Example 2

[0079] First, a polymer coating is formed on the outer surface of the tube body 1 by electrospinning to obtain a double J-shaped coating, and the inner surface of the coating is closely attached to the outer surface of the tube body 1, thereby obtaining a ureteral stent. The tube body 1 of the ureteral stent is woven and formed, so that the ureteral stent has good flexibility, and the J-shapes at both ends play a good anchoring role in the kidney and bladder.

[0080] In more detail, the tube body 1 is formed by interlacing and weaving 48 polylactide-glycolide (PLGA) degradable fibers (weight average molecular weight of 100,000 g / mol, degradation period of 6 months) with a diameter of 0.05 mm, forming a dense tubular structure, and then heat-setting into a double J-shaped structure. In addition, the number of weaving intersections along the circumferential direction of the tube body 1 is 24, and the angle β of the weaving grid is 80°. In addition, the axial length 3 of the middle part 12 of the tube body 1 is 280 mm, the circles of the J-shaped ends 11 at both ends are circles and the outer diameter D is 15 mm, and the vertical distance between the free end of the J-shaped end 11 of the tube body 1 and the middle part 12 is 6 mm. In addition, the coating is made of left-handed polylactic acid (PLLA) (weight average molecular weight of 600,000 g / mol, degradation period of 24 months) sprayed on the outer surface of the tube body 1 by electrospinning to form a coating with a thickness of 0.15 mm and a curvature of π / 4, and is heat-formed into a double J-shaped structure together with the tube body 1 at a temperature of 80°C and heating conditions for 60 minutes.

[0081] The ureteral stent prepared in this embodiment begins to degrade 6 months after implantation in the body. It has a good urine drainage function, can provide good mechanical support strength, and improve urinary tract stenosis and obstruction. Specifically, the ureteral stent is implanted in a simulated urinary system, the simulated ureter diameter is 2.5 mm, artificial simulated urine (Artificial Urine Solution, AUS), buffer (pH = 6.0 ± 0.5) is selected as the simulated body fluid, and the rotation speed is set to 65 revolutions per minute in a constant temperature shaker, and the ambient temperature is adjusted to 37 ° C for a simulated degradation experiment. The test results of the in vitro degradation simulation experiment show that the radial support force of the stent is 140 kPa at 6 months, the skeleton structure has not collapsed, and no obvious stent fragments are found during the degradation process. The simulated urinary system has a normal drainage function. The "J-shaped" parts at both ends of the stent are anchored in the area simulating the kidney and bladder, and no phenomena such as falling off and displacement occur.

[0082] Compared with Example 1, the ureteral stent of Example 2 has more braiding intersections, a denser braiding, and a greater radial supporting force.

[0083] Example 3

[0084] A double J-shaped coating is also obtained by heat setting, and the coating is sutured on the tube body 1, that is, the coating is set on the outer surface, and the suture passes through the coating, and a part of the suture passes through the tube body 1, and a part of the suture passes through the tube body 1, and the surface of the coating and the surface of the tube body 1 are also closely fitted, so as to obtain a ureteral stent. Since the tube body 1 is woven and formed, the ureteral stent has good flexibility, and can also play a good anchoring role in the kidney and bladder through the J-shape at both ends.

[0085] The tube body 1 is formed by interlacing and weaving 24 polylactide-caprolactone (PLCL) degradable fibers (weight average molecular weight of 250,000 g / mol, degradation period of 10 months) with a diameter of 0.15 mm, forming a dense tubular structure, and then heat-setting into a double J-shaped structure. In addition, the number of weaving intersections along the circumferential direction of the tube body 1 is 12, and the angle β of the weaving grid is 60°. In addition, the axial length 3 of the middle part 12 of the tube body 1 is 160 mm, the J-shaped end portions 11 at both ends are circles with an outer diameter of 22 mm, and the vertical distance h between the free end of the J-shaped end portion 11 of the tube body 1 and the middle part 12 is 10 mm. In addition, the coating is formed by blow molding polyethylene glycol (PEG) (weight average molecular weight of 400,000 mol, degradation period of 12 months) to have a thickness of 0.08 mm and a curvature of π / 2, and is heat-set into a double J-shaped structure at 80°C and 60 minutes.

[0086] The ureteral stent prepared in this embodiment is nested in the outer contour of the tube body 1 to assist the tube body 1 in maintaining a J-shaped structure, thereby enhancing the mechanical support strength of the stent and improving the anchoring performance of the stent in the kidney and bladder. The ureteral stent begins to degrade 10 months after implantation in the body. It has a good urine drainage function, can provide good mechanical support strength, and improve urinary tract stenosis and obstruction. Specifically, the ureteral stent is implanted in a simulated urinary system, the simulated ureter diameter is 2.5mm, artificial simulated urine (Artificial Urine Solution, AUS), buffer (pH = 6.0 ± 0.5) is selected as a simulated body fluid, and the speed is set to 65 revolutions per minute in a constant temperature shaker, and the temperature is adjusted to 37 ° C for a simulated degradation experiment. The test results of the in vitro degradation simulation experiment show that the radial support force of the stent is 100kPa at 6 months, the skeleton structure has not collapsed, and no obvious stent fragments are found during the degradation process. The simulated urinary system has a normal drainage function. The "J-shaped" parts at both ends of the stent were anchored in the area simulating the kidney and bladder, and no phenomena such as falling off or shifting occurred.

[0087] Furthermore, an embodiment of the present invention also provides a method for preparing the above-mentioned ureteral stent, comprising:

[0088] A mesh tube body is prepared by using a degradable polymer material, and the tube body is heat-formed into a double J shape at a predetermined temperature;

[0089] A film-shaped support component is prepared by using a degradable polymer material, and the support component is arranged on the tube body.

[0090] Preferably, the tube body 1 is woven from degradable fibers, and the tube body is heat-set into a double J shape at a temperature of 50°C to 80°C. In addition, the support component 2 can be arranged on the tube body 1 in the following manner: a sheet-like coating can be first obtained by a blow molding process, and then the sheet-like coating is heat-set into a double J shape, and then the double J-shaped coating is nested on the double J-shaped tube body and fixed. Here, as mentioned above, the sheet-like coating can also be heat-set into a double J shape after being nested on the tube body. In addition, the support component 2 can also be arranged on the tube body in the following manner: a coating is formed on the outer surface of the tube body by an electrospinning process, and then the coating and the tube body are heat-set into a double J shape together, or the tube body is heat-set into a double J shape in advance before electrospinning, so that the coating generated by electrospinning is directly in a double J shape. Alternatively, the supporting member 2 may be arranged on the tube body by directly spraying the degradable polymer material on the tube body to form a coating, and then heat-setting them together into a double J shape. Before spraying, the tube body 1 may be heat-set into a double J shape in advance, so that the coating formed by spraying is a double J shape. It should be known that the film formed by electrospinning has tiny holes, while the film formed by blow molding has no holes.

[0091] According to the technical solution provided by the above embodiment, the ureteral stent of the present invention not only has good radial support force, can fully expand the urethra of the narrow part and drain urine, but also the tube body is preferably woven and formed, degrades evenly and can be completely degraded, and no residual degradation fragments of the stent are left, thereby avoiding the inflammatory stimulation and scratching of the urethral mucosa caused by insufficient degradation of the stent in the past. At the same time, the tube body in the ureteral stent is woven from degradable materials, has good flexibility and support performance, and can be retained in the body along the direction of the patient's urethra, so the stent will not have a strong foreign body sensation when it is retained in the patient's body. In particular, the coating of the support component can make the stent have good mechanical strength, resist the torque and axial elongation of urethral peristalsis, and at the same time make the J-shaped ends of the stent better positioned in the kidney and bladder to prevent the stent from shifting. This ureteral stent has a simple structure and is easy to process and shape. It can provide good support and urine drainage when implanted in the patient's body. As the patient's hydronephrosis is alleviated and the ureter recovers, the stent will degrade on its own and eventually be excreted from the body in the form of water and carbon dioxide. There is no need for a second surgery to remove it, thus avoiding secondary damage to the patient and improving the treatment effect.

[0092] It should be understood that the above-mentioned embodiments specifically disclose the features of the preferred embodiments of the present invention so that those skilled in the art can better understand the present invention. Those skilled in the art should understand that, based on the disclosure of the present application document, it is easy to make appropriate modifications to the present invention to achieve the same purpose and / or achieve the same advantages as the embodiments disclosed in the present invention. Those skilled in the art should also recognize that such similar constructions do not depart from the scope disclosed in the present invention, and they can be variously changed, replaced and altered without departing from the scope disclosed in the present invention.

Claims

1. A ureteral stent, comprising a degradable mesh tube body and a degradable support component, wherein the tube body is a double J-shaped structure, the tube body is woven from degradable fibers, the elongation at break of the degradable fibers is greater than 20%, the tensile strength of the degradable fibers is greater than 1 cN / dtex, and the tube body is heat-set into a double J shape at a temperature of 50°C to 80°C after being woven; the support component comprises a coating, the support component is arranged on the tube body, the support component covers the surface of the tube body, or the support component covers the surface of the tube body and is embedded in the tube body; the degradation rate of the support component is lower than the degradation rate of the tube body; the tube body comprises J-shaped ends at both ends and a middle portion between the two J-shaped ends; The entire axial length of the tube body is auxiliary supported by the coating, and the supporting component covers a portion of the circumferential surface of the tube body; the materials of the tube body and the supporting component are both high-molecular compounds, the weight-average molecular weight of the tube body is 100,000 to 300,000 g / mol, and the weight-average molecular weight of the supporting component is 300,000 to 800,000 g / mol.

2. The ureteral stent according to claim 1, It is characterized in that The arc of the supporting component in the circumferential direction is π / 6 to π.

3. The ureteral stent according to claim 1, It is characterized in that The degradation time of the pipe body is 6 to 12 months, and the degradation time of the supporting component is 6 to 36 months.

4. The ureteral stent according to claim 1, It is characterized in that The diameter of the degradable fiber is 0.05 mm to 0.15 mm.

5. The ureteral stent according to claim 1, It is characterized in that The material of the tube body is selected from one or a combination of the following materials: Polylactic acid, L-lactic acid, D-lactic acid, polyglycolic acid, poly-ε-caprolactone, polyethylene glycol, polyphthalamide, polyethylene oxide and polyvinyl alcohol, and a copolymer formed by at least two of lactic acid, L-lactic acid, D-lactic acid, glycolic acid, ε-caprolactone, ethylene glycol, phthalamide, ethylene oxide and vinyl alcohol; and / or, the material of the supporting member is selected from one or more of the following materials: Polylactic acid, L-lactic acid, D-lactic acid, polyglycolic acid, poly-ε-caprolactone, polyethylene glycol, polyphthalamide, polyethylene oxide and polyvinyl alcohol, and copolymers formed by at least two of lactic acid, L-lactic acid, D-lactic acid, glycolic acid, ε-caprolactone, ethylene glycol, phthalamide, ethylene oxide and vinyl alcohol.

6. The ureteral stent according to claim 1, It is characterized in that The thickness of the coating is 0.05 mm to 0.15 mm.

7. The ureteral stent according to claim 1, It is characterized in that The tensile elastic modulus of the support member is higher than 1 GPa.

8. The ureteral stent according to claim 1, It is characterized in that The middle portion has an axial length of 120 mm to 300 mm and an outer diameter of 1.4 mm to 2.6 mm.

9. The ureteral stent according to claim 1, It is characterized in that The braided grid of the tube body has an angle, which is an acute angle, which is 60° to 80°, and the number of braided interlaced points of the tube body along its circumferential direction is 8 to 32.

10. The ureteral stent according to claim 1, It is characterized in that The supporting component covers the inner surface or the outer surface of the tube body.

11. A method for preparing a ureteral stent according to any one of claims 1 to 10, It is characterized in that include: A mesh tube body is formed by weaving degradable fibers, and the tube body is heat-formed into a double J shape at a temperature of 50° C. to 80° C.; A film-like support component is prepared by using a degradable polymer material, and the support component is arranged on the entire length of the tube body and covers a part of the surface of the tube body along the circumferential direction, or the support component covers the surface of the tube body and is embedded in the tube body.

12. The preparation method according to claim 11, It is characterized in that The method of arranging the supporting component on the tube body includes: Obtaining a coating through a blow molding process, and nesting the coating on the tube body, and after the nesting, heat-setting the coating together with the tube body into a double J shape, or, before the nesting, heat-setting the coating and the tube body into a double J shape respectively in advance; Alternatively, the supporting component is arranged on the tube body in the following manners: Forming a coating on the outer surface of the tube body by an electrospinning process, and after electrospinning, heat-setting the coating and the tube body together into a double J shape, or, before electrospinning, heat-setting the tube body into a double J shape in advance, so that the coating generated by electrospinning is also in a double J shape; Alternatively, the supporting component is arranged on the tube body in the following manners: A degradable polymer material is sprayed on the outer surface of the tube body to form a coating, and after spraying, the coating and the tube body are heat-formed together into a double J shape, or, before spraying, the tube body is heat-formed into a double J shape in advance so that the coating generated by spraying is also in a double J shape.

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