Degradable ureteral stent

Abstract

The utility model discloses a degradable ureteral stent which comprises a first curly section, a middle connecting section and a second curly section which are sequentially connected to form a double-J-shaped structure. The ureteral stent comprises a woven mesh tube body and a degradable supporting tube, the woven mesh tube body is a biodegradable magnesium alloy woven mesh, and the degradable supporting tube is a PLGA tube body or a PLGA tube body; the woven mesh pipe body is embedded in the degradable supporting pipe; the degradable supporting tube is used for supporting the woven mesh tube body into a tubular structure and keeping the tubular structure stable; wherein supporting wire rings are arranged at the two ends of the woven mesh pipe body respectively, and the supporting wire rings are fixedly connected with the ends of the woven mesh pipe body. The ureteral stent begins to degrade after expected three months, so that pain brought to a patient when the ureteral stent is taken out is avoided; the supporting wire rings are arranged at the two ends of the woven mesh tube body respectively, the supporting effect is achieved, the structural strength of the opening in the end of the woven mesh tube body is improved, and the situation that the opening in the end of the woven mesh tube body is closed under the action of external force, and the urinary catheterization function cannot be achieved is prevented.

Description

Technical Field

[0001] The utility model relates to the field of urinary treatment medical equipment, in particular to a degradable ureteral stent. Background Art

[0002] Ureteral stenosis is a common urinary system disease. Stenosis may lead to secondary infection, forming ureteral diverticulum, periureteritis, prostatitis or epididymo-orchitis. If the urinary obstruction cannot be relieved for a long time, it may eventually lead to hydronephrosis, renal damage and uremia. Ureteral stenosis is not uncommon in clinical practice. In addition to congenital stenosis, secondary ureteral stenosis is mainly caused by iatrogenic stenosis, stone incarceration, infection, endometriosis, retroperitoneal fibrosis, malignant tumors, radiotherapy, etc.

[0003] Double J ureteral stents are widely used in urological surgery and are suitable for kidney stones, ureteral stones, hydronephrosis, kidney transplantation, benign tumors of the kidney and ureter, etc., the above urinary tract surgeries as well as extracorporeal shock wave lithotripsy, dilation of ureteral stenosis and other treatment processes; Double J ureteral stents are used for temporary internal drainage from the junction of the renal pelvis and ureter to the bladder; after being implanted in the ureter, it can drain urine and prevent ureteral stenosis and adhesion blockage.

[0004] The current ureteral stents are mainly made of silicone or rubber. After the ureteral stent is implanted in the human body for 3 to 5 months, the internal structure of the urethra remains stable, and the ureteral stent will be removed thereafter. However, after several months of adaptation, the internal mucosal tissue of the urethra fits tightly with the ureteral stent, which will cause great pain to the patient during the removal of the ureteral stent and is prone to secondary infection. At the same time, the current ureteral stent treatment cannot inhibit and prevent various inflammatory reactions because there are no antibacterial and anti-inflammatory preparations attached to the stent, which is not conducive to wound healing.

[0005] Therefore, we need to design a degradable ureteral stent that can inhibit tissue proliferation, so as to reduce the patient's pain during use and eliminate the need for surgery to remove it. Summary of the invention

[0006] In order to overcome the defects of the prior art, the purpose of the utility model is to provide a degradable ureteral stent to solve the problem that the existing ureteral stent needs to be removed again to cause secondary damage to the patient.

[0007] To this end, the utility model proposes a degradable ureteral stent, comprising a first curled section, a middle connecting section and a second curled section connected in sequence, the curling directions of the first curled section and the second curled section are opposite to each other, forming a double J-shaped structure; the ureteral stent is a multi-layer structure, comprising a woven mesh tube body and a degradable support tube, the woven mesh tube body is a biodegradable magnesium alloy woven mesh, and the degradable support tube is a PLGA tube body or a PLA tube body; and the woven mesh tube body is embedded in the degradable support tube; the degradable support tube is used to support the woven mesh tube body into a tubular structure and keep it stable; wherein, support wire loops are respectively provided at both ends of the woven mesh tube body, and the support wire loops are fixedly connected to the ends of the woven mesh tube body.

[0008] As a preferred technical solution of the present invention, a sustained-release drug layer is arranged on the outer side of the degradable support tube, and the sustained-release drug layer is glucocorticoid.

[0009] As a preferred technical solution of the present invention, a lubricating layer is further provided on the outer side of the sustained-release drug layer; the lubricating layer is a polypropylene or PVP film.

[0010] As a preferred technical solution of the present invention, the degradable support tube is a tube body formed by mixing PLGA polymer or PLA polymer with dexamethasone particles through compression and thermoforming process to form a PLGA tube body or a PLA tube body.

[0011] As a preferred technical solution of the present invention, the wall thickness of the degradable support tube is in the range of 0.25 mm to 0.4 mm.

[0012] As a preferred technical solution of the present invention, the diameter of the degradable support tube is in the range of 6Fr to 12Fr.

[0013] As a preferred technical solution of the present invention, the braided mesh tube body is woven from magnesium alloy wires with a diameter of Φ0.1-0.25 mm to form a tubular braided mesh.

[0014] As a preferred technical solution of the present invention, the magnesium alloy wire is one of ZK60, AZ31, ZE41, AZ91, Mg-Zn, Mg-Zn-Mn or Mg-Ca.

[0015] As a preferred technical solution of the present invention, a plurality of equally spaced annular developing lines are arranged on the middle connecting section.

[0016] The degradable ureteral stent provided by the utility model combines a biodegradable magnesium alloy woven mesh with a degradable high molecular polymer. The woven mesh tube body is a frame structure with good tensile strength. The degradable support tube has a shaping effect to prevent the woven mesh tube body from shrinking due to lack of a supporting structure, thereby preventing the catheterization function from being realized. The ureteral stent is expected to start degrading after three months to prevent pain to the patient when the ureteral stent is removed. Support wire loops are respectively provided at both ends of the woven mesh tube body to play a supporting role, thereby improving the structural strength of the opening at the end of the woven mesh tube body, thereby preventing the opening at the end of the woven mesh tube body from being closed due to external force, thereby preventing the catheterization function from being realized.

[0017] In addition, by mixing dexamethasone particles into the degradable support tube, various inflammatory reactions can be inhibited and prevented; by setting a sustained-release drug layer containing glucocorticoids, the thermal damage caused by the laser during ureteral lithotripsy or the stimulation of the ureteral mucosa by the acidic substances produced during the degradation of polylactic acid can be improved.

[0018] In addition to the above-described purposes, features and advantages, the present application also has other purposes, features and advantages. The present application will be further described in detail with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 This is a schematic diagram of the structure of the degradable ureteral stent of the utility model;

[0021] Figure 2 It is a partial enlarged view of the A part of the degradable ureteral stent of the utility model;

[0022] Figure 3 It is a partial enlarged view of position B in the degradable ureteral stent of the utility model;

[0023] Figure 4 This is a schematic diagram of the cross-sectional structure of the degradable ureteral stent of the utility model;

[0024] Description of Reference Numerals

[0025] 1. First curling section; 2. Middle connecting section; 3. Second curling section; 4. Annular developing line; 11. Braided mesh tube body; 12. Degradable support tube; 13. Sustained-release drug layer; 14. Lubricating layer; 15. Support wire loop; 16. Dexamethasone particles. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] like Figure 1 to Figure 4 As shown, the degradable ureteral stent of the utility model comprises a first curled segment 1, a middle connecting segment 2 and a second curled segment 3 which are connected in sequence to form a double J-shaped structure; the first curled segment 1 is used to be placed in the renal pelvis, the second curled segment 3 is used to be placed in the bladder, and the middle connecting segment is implanted in the ureter; the curling directions of the first curled segment 1 and the second curled segment 3 are opposite.

[0028] like Figure 4 As shown, the ureteral stent is a multi-layer structure, and the ureteral stent includes a braided mesh tube body 11 and a degradable support tube 12. A sustained-release drug layer 13 is arranged on the outside of the degradable support tube 12, and a lubricating layer 14 is also arranged on the outside of the sustained-release drug layer 13. The braided mesh tube body 11 is a biodegradable magnesium alloy braided mesh; and the degradable support tube 12 is a tube body composed of PLGA (polylactic acid-glycolic acid copolymer); the braided mesh tube body 11 is embedded in the degradable support tube 12.

[0029] The braided mesh tube body 11 is similar to the steel bars in reinforced concrete structures, and is a frame structure with good tensile strength; the degradable support tube 12 is similar to the concrete in reinforced concrete structures, and is used to support the braided mesh tube body 11 into a tubular structure to prevent the braided mesh tube body 11 from shrinking due to lack of support structure and being unable to achieve the urinary catheterization function.

[0030] The PLGA tube body is composed of polylactic acid-glycolic acid copolymer, which is randomly polymerized from two monomers, lactic acid and glycolic acid. It is a degradable functional macromolecular organic compound with good biocompatibility, non-toxicity, good capsule and film forming properties, and is widely used in pharmaceutical, medical engineering materials and modern industrial fields. In addition, the degradable support tube 12 can also be a thin tube made of one of polylactic acid (PLLA), polyglycolic acid (PGA), polyhydroxybutyrate (PHB) or polycaprolactone (PCL).

[0031] The wall thickness of the degradable support tube 12 is in the range of 0.25 mm to 0.4 mm, and the diameter of the degradable support tube 12 is in the range of 6 Fr to 12 Fr (2 mm to 4 mm). It is expected that the ureteral stent will begin to degrade after three months, and generally the proliferation of fibroblasts will begin to decrease after three months, and the ureteral scar will be stable; at this time, the purpose of the drug effect has been achieved.

[0032] like Figure 2As shown, the braided mesh tube body 11 is woven from biodegradable magnesium alloy wires with a diameter of Φ0.1-0.25 mm to form a tubular braided mesh, wherein the magnesium alloy is one of ZK60, AZ31, ZE41, AZ91, Mg-Zn, Mg-Zn-Mn or Mg-Ca. Biodegradable magnesium alloys are known as the third generation of biomedical materials as degradable medical materials. Due to their excellent mechanical properties, good biocompatibility and biodegradable absorption characteristics, they have become a hot topic in the field of medical implant materials.

[0033] By utilizing the characteristics of magnesium alloy materials that are prone to corrosion (degradation) in the human body environment, the medical clinical purpose of gradually degrading metal implants in the body until they eventually disappear is achieved. In orthopedic implants, it has a density and elastic modulus close to that of bones. Medical magnesium alloys also have a controllable corrosion rate and have good application prospects in cardiovascular implants, ureteral implants and bone repair.

[0034] In addition, if Figure 3 As shown, support wire loops 15 are respectively provided at both ends of the braided mesh tube body 11, and the support wire loops 15 are formed by winding a plurality of annular biodegradable magnesium alloys. The support wire loops 15 are fixedly connected to the ends of the braided mesh tube body 11 to play a supporting role, thereby improving the structural strength of the opening at the end of the braided mesh tube body 11 and preventing the opening at the end of the braided mesh tube body 11 from being closed by external force, thereby failing to achieve the catheterization function.

[0035] In this embodiment, the sustained-release drug layer 13 is a glucocorticoid, and the coating of the glucocorticoid is slowly released as the material degrades. Glucocorticoids reduce and prevent the response of tissues to inflammation, thereby reducing the manifestation of inflammation. At an appropriate dose, it can inhibit the proliferation and migration of smooth muscle cells, thereby inhibiting excessive proliferation of the intima and preventing restenosis after stent surgery. At the same time, during the release of glucocorticoids, the thermal damage caused by the laser during ureterolithotomy or the irritation of the ureteral mucosa by the acidic substances produced during the degradation of polylactic acid is improved.

[0036] In addition, dexamethasone particles 16 are mixed in the degradable support tube 12, and PLGA polymer or PLA polymer is mixed with dexamethasone (DA). The polymer mass fraction is 72.3%, and the dexamethasone particles are 27.7%. The implant is made by compression and thermoforming technology. Dexamethasone can inhibit and prevent various inflammatory reactions. Its anti-inflammatory effect is mainly through inhibiting the aggregation and activation of inflammatory cells, reducing the production of inflammatory mediators, thereby alleviating inflammatory reactions.

[0037] In addition, a plurality of equally spaced annular developing lines 4 are provided on the middle connecting section 2. The annular developing lines 4 are made of a radiopaque material with a portion of barium sulfate, and the distance between each annular developing line is 50 mm. The setting of the annular developing lines can assist doctors in determining the length of the implanted ureteral stent, thereby making it more convenient to use. The lubricating layer 14 is a polypropylene or PVP film, which has a hydrophilic super-slip property and reduces the friction between the stent and the urethra during implantation.

[0038] The working principle and working process of the degradable ureteral stent of the present invention are briefly described below.

[0039] By combining a biodegradable magnesium alloy braided mesh with a degradable high molecular polymer, the braided mesh tube body is a frame structure with good tensile strength; the degradable support tube has a shaping effect to prevent the braided mesh tube body from shrinking due to lack of a support structure and failing to achieve the urinary catheterization function; the ureteral stent is expected to begin to degrade after three months to avoid causing pain to the patient when the ureteral stent is removed; by arranging support wire loops at both ends of the braided mesh tube body, a support effect is played to improve the structural strength of the opening at the end of the braided mesh tube body, and to prevent the opening at the end of the braided mesh tube body from closing due to external force and failing to achieve the urinary catheterization function. The utility model has a simple structure, is easy to operate, and has a low manufacturing cost, and provides a treatment plan with excellent performance.

[0040] In addition, by mixing dexamethasone particles into the degradable support tube, various inflammatory reactions can be inhibited and prevented; by setting a sustained-release drug layer containing glucocorticoids, the thermal damage caused by the laser during ureteral lithotripsy or the stimulation of the ureteral mucosa by the acidic substances produced during the degradation of polylactic acid can be improved.

[0041] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A degradable ureteral stent, characterized in that: It comprises a first curling section (1), a middle connecting section (2) and a second curling section (3) which are connected in sequence, wherein the curling directions of the first curling section (1) and the second curling section (3) are opposite to each other, forming a double J-shaped structure; The ureteral stent is a multi-layer structure, comprising a braided mesh tube body (11) and a degradable support tube (12); the braided mesh tube body (11) is a biodegradable magnesium alloy braided mesh, and the degradable support tube (12) is a PLGA tube body or a PLA tube body; and the braided mesh tube body (11) is embedded inside the degradable support tube (12); the degradable support tube (12) is used to support the braided mesh tube body (11) into a tubular structure and maintain stability; wherein, support wire loops (15) are respectively provided at both ends of the braided mesh tube body (11), and the support wire loops (15) are fixedly connected to the ends of the braided mesh tube body (11).

2. The degradable ureteral stent according to claim 1, characterized in that: A sustained-release drug layer (13) is arranged on the outer side of the degradable support tube (12); the sustained-release drug layer (13) is glucocorticoid.

3. The degradable ureteral stent according to claim 2, characterized in that: A lubricating layer (14) is also provided on the outside of the sustained-release drug layer (13); the lubricating layer (14) is a polypropylene or PVP film.

4. The degradable ureteral stent according to claim 1, characterized in that: The degradable support tube (12) is a tube body formed by mixing PLGA polymer or PLA polymer with dexamethasone particles (16) through compression and thermoforming processes.

5. The degradable ureteral stent according to claim 1, characterized in that: The wall thickness of the degradable support tube (12) is in the range of 0.25 mm to 0.4 mm.

6. The degradable ureteral stent according to claim 1, characterized in that: The diameter of the degradable support tube (12) is in the range of 6Fr to 12Fr.

7. The degradable ureteral stent according to claim 1, characterized in that: The braided mesh tube body (11) is braided from magnesium alloy wires with a diameter of Φ0.1-0.25 mm to form a tubular braided mesh.

8. The degradable ureteral stent according to claim 7, characterized in that: The magnesium alloy wire is one of ZK60, AZ31, ZE41, AZ91, Mg-Zn, Mg-Zn-Mn or Mg-Ca.

9. The degradable ureteral stent according to claim 1, characterized in that: The middle connecting section (2) is provided with a plurality of annular developing lines (4) at equal intervals.

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