Degradable and anti-infection child ureter covered stent

Abstract

The invention relates to a degradable and anti-infection child ureter covered stent. The degradable and anti-infection child ureter covered stent comprises a preassembled stent, the preassembled stent comprises a stent main body which is tubular after being released and a limiting mechanism for preventing falling off; the stent main body comprises a wave-shaped degradable memory metal wire and a macromolecular covering film which covers the surface of the memory metal wire and contains anti-infection components, the memory metal wire surrounds in a spiral shape, and the limiting mechanism is arranged on one side of the stent main body; the overall size of the preassembled stent is specially designed for the diameter and the length of the ureter of a child, anti-infection components such as antibiotics or antibacterial agents are added into the polymer covering film, an antibacterial environment can be formed on the surface of the stent, bacterial growth and biofilm formation can be effectively prevented and inhibited, the risk of postoperative urinary system infection of a child patient is remarkably reduced, and the patient compliance is improved. The composition is especially suitable for children patients with incompletely developed immune systems.

Description

Technical Field

[0001] The present invention relates to the technical field of medical equipment, and in particular to a degradable and infection-resistant ureteral stent graft for children. Background Art

[0002] Ureteral stenosis is a common urinary tract disease, particularly unique and complex in children. Ureteral stenosis in children can be divided into two categories: congenital ureteral stenosis and secondary ureteral stenosis. Congenital ureteral stenosis is more common in children. Secondary ureteral stenosis can be caused by inflammatory irritation, tumor compression, stone impaction, and post-operative ureteral stenosis.

[0003] In existing technologies, migration of ureteral covered stents refers to changes in the stent's position within the ureter, potentially moving upward or downward, or even completely detaching from the ureter. Due to the lack of an effective fixation mechanism, the stent's stability within the ureter is insufficient, making it susceptible to positional changes due to factors such as urine flow and ureteral peristalsis. This problem is particularly prominent in children, whose ureters are smaller in diameter and more fragile, making them difficult to accommodate with traditional adult stents.

[0004] Furthermore, for children, traditional non-degradable stents often require a second surgical procedure to remove, increasing surgical risk and patient pain. Furthermore, children's immune systems are not fully developed, increasing the risk of infection after ureteral stent placement. Infection not only compromises treatment effectiveness but can also lead to more serious complications.

[0005] Migration of the stent may prevent it from effectively supporting the ureter, thus compromising treatment effectiveness. Migration can also cause discomfort and pain for the patient. Stent movement within the ureter can irritate the ureteral wall, leading to symptoms such as dysuria and frequent urination. For young children, this discomfort can be more difficult to express and alleviate. Therefore, there is a need for a biodegradable, infection-resistant ureteral stent graft designed specifically for children. Summary of the Invention

[0006] The purpose of the present invention is to provide a degradable and anti-infection pediatric ureteral covered stent, which is designed specifically for pediatric patients. A limiting mechanism is set in the pre-installed stent. The design of the limiting mechanism can increase the stability of the stent in the child's ureter. The limiting anchor enables the stent to better fit the child's ureteral wall, reducing the change in stent position caused by factors such as urine flow and ureteral peristalsis.

[0007] At the same time, the present invention uses degradable materials to make the stent body, avoiding the need for a second operation to remove the stent, reducing the pain of child patients and the burden on their families; anti-infection ingredients are added to the stent coating, which can effectively inhibit bacterial growth and reduce the risk of postoperative infection. It is particularly suitable for child patients whose immune systems have not yet fully developed.

[0008] The stent size, material strength and flexibility of the present invention are specially designed for the characteristics of children's ureters, solving the problems of ureteral stent migration, the need for secondary surgery for removal, and high infection risk in children raised in the above background technology.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a degradable and anti-infection pediatric ureteral stent graft, comprising:

[0010] It comprises a pre-installed stent; the pre-installed stent comprises a stent body which is tubular after being released and a limiting mechanism for preventing it from falling off; the stent body comprises a wavy degradable memory metal wire and a polymer coating containing anti-infection components covering the surface of the memory metal wire, the memory metal wire is spirally wound, and the limiting mechanism is arranged on one side of the stent body; the overall size of the pre-installed stent is specially designed for the diameter and length of the ureter of children.

[0011] Preferably, the limiting mechanism includes a metal wire connecting portion fixedly mounted on one side of the memory metal wire, and a limiting anchor for reducing the migration of the stent is fixedly mounted on one side of the metal wire connecting portion.

[0012] Preferably, a radiopaque marker is installed in the memory wire.

[0013] Preferably, the polymer coating is configured as a degradable polymer coating containing antibiotics or antibacterial agents, and the degradable memory metal wire is made of at least one of magnesium alloy, zinc alloy or iron alloy, and has a controllable degradation cycle of 6-12 months.

[0014] Preferably, the device further includes a ureteral stent placement mechanism for inserting a pre-installed stent into the ureter of a child. The ureteral stent placement mechanism includes a thin-diameter cannula specifically for children. The interior of the cannula is connected to a Y-shaped connector. A connector is provided on one side of the Y-shaped connector. The connector is connected to one end of the cannula, and the pre-installed stent is provided on the surface of the cannula at an end away from the connector.

[0015] Preferably, one end of the cannula is provided with a visible black mark on the outer tube, and the visible black mark on the outer tube is arranged on the surface of the pre-installed stent.

[0016] Preferably, the cannula has a length of 12-18 cm and a circumference of 4-5 Fr, and is suitable for children of different ages.

[0017] Preferably, it also includes a urethral stent insertion mechanism for inserting a pre-installed stent into the urethra, the urethral stent insertion mechanism includes a handle, an insertion tube is provided on one side of the handle, the pre-installed stent is provided at the end of one end of the insertion tube, and the surface of the handle is installed with an injection port, a fixing clip, an endoscope, a TeFrlon sheath button, a safety lock button and a trigger.

[0018] Preferably, the insertion tube has a length of 18-24 cm and a circumference of 5-6 Fr.

[0019] Preferably, the connector is a Luer-type connector.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention provides a limiting mechanism within the pre-installed stent. The design of the limiting mechanism can increase the stability of the stent within the child's ureter. The limiting anchor enables the stent to better fit the child's ureteral wall, reducing stent position changes caused by factors such as urine flow and ureteral peristalsis. This improved stability helps ensure that the stent can continuously and effectively perform its supporting role, thereby maintaining unobstructed urine drainage.

[0022] 2. The present invention uses biodegradable materials to make memory metal wires. The stent can naturally degrade after a preset period of time (6-12 months) in the body, avoiding the problem of traditional stents requiring a second surgery to remove them, greatly alleviating the pain and psychological burden of child patients, and reducing anesthesia and surgical risks.

[0023] 3. Antibiotics or antibacterial agents and other anti-infective ingredients are added to the polymer coating of the present invention, which can form an antibacterial environment on the stent surface, effectively prevent and inhibit bacterial growth and biofilm formation, and significantly reduce the risk of postoperative urinary tract infection in children. It is particularly suitable for children whose immune systems are not yet fully developed.

[0024] 4. The stent size, material strength and flexibility of the present invention are specially designed for the characteristics of children's ureters. The use of smaller diameter cannulas and stents is more in line with the anatomical structure of children's ureters, improving implant accuracy and patient comfort.

[0025] 5. Through material innovation and structural optimization, the present invention enables the stent to have the characteristics of self-expansion and uniform radial force. The polymer coating forms a leak-proof lumen, preventing mucosal tissue from embedding into the tube, reducing scaling, calcification and stone formation in the lumen, and is particularly suitable for the long-term treatment needs of pediatric patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the pre-installed bracket of the present invention;

[0027] Figure 2 This is a linear removal diagram of the stent of the present invention;

[0028] Figure 3 This is a diagram of the ureteral stent placement mechanism of the present invention;

[0029] Figure 4 This is a three-dimensional diagram of the urethral stent placement mechanism of the present invention.

[0030] In the figure: 1. Pre-installed stent; 11. Stent body; 111. Memory wire; 112. Polymer coating; 12. Limiting mechanism; 121. Wire connection; 122. Limiting anchor; 2. Radiopaque marker; 3. Ureteral stent placement mechanism; 31. Cannula; 32. Y-type connector; 33. Connector; 4. Visible black mark on outer tube; 5. Urethral stent placement mechanism; 51. Handle; 52. Insertion tube; 53. Injection port; 54. Fixing clip; 55. Endoscope; 56. TeFrlon sheath button; 57. Safety lock button; 58. Trigger. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] See also Figure 1-4 The present invention provides a technical solution: a degradable and anti-infection ureteral stent for children, comprising:

[0034] Pre-installed bracket 1;

[0035] The pre-installed stent 1 comprises a stent body 11 which is tubular after being released and a limiting mechanism 12 for preventing it from falling off;

[0036] The stent body 11 comprises a wavy degradable memory metal wire 111 and a polymer coating 112 containing anti-infective components covering the surface of the memory metal wire 111. The memory metal wire 111 is spirally wound, and the limiting mechanism 12 is provided on one side of the stent body 11.

[0037] Specifically, a limiting mechanism 12 is provided in the pre-installed stent 1. The design of the limiting mechanism 12 can increase the stability of the stent in the child's ureter. The limiting anchor 122 enables the stent to better fit the wall of the child's ureter, thereby reducing the change in the position of the stent caused by factors such as urine flow and ureteral peristalsis. This improvement in stability helps to ensure that the stent can continuously and effectively play a supporting role, thereby maintaining unobstructed drainage of urine.

[0038] The limiting mechanism 12 includes a metal wire connecting portion 121 fixedly mounted on one side of the memory metal wire 111, and a limiting anchor 122 for reducing stent migration is fixedly mounted on one side of the metal wire connecting portion 121;

[0039] The degradable memory wire 111 is made of at least one of a magnesium alloy, a zinc alloy, or an iron alloy. In this embodiment, a magnesium alloy containing rare earth elements (such as an Mg-Y-Nd-Zr alloy) is preferred, as it exhibits excellent biocompatibility and a controllable degradation rate. By adjusting the alloy composition ratio and surface treatment process, the memory wire 111 can maintain its mechanical strength in the body for 6-12 months, after which it gradually degrades into harmless ions that are metabolized and excreted by the body, eliminating the need for secondary surgical removal.

[0040] The polymer coating 112 is configured as a degradable polymer coating containing anti-infective components. In this embodiment, the polymer coating 112 uses poly(lactic-co-glycolic acid) (PLGA) as its base material, and antibacterial components such as antibiotics (such as gentamicin and vancomycin) or silver nanoparticles are loaded into the polymer through a special process. These anti-infective components are continuously and slowly released during the stent's indwelling period, effectively inhibiting bacterial adhesion and biofilm formation, thereby reducing the risk of urinary tract infections in children.

[0041] In this embodiment, the limiting anchor 122 can limit the stent, reduce the displacement of the stent, and the stent can be disassembled and taken out in a linear shape. At the same time, the pre-installed stent 1 has high comfort, can self-expand, and has uniform radial force, which increases the comfort of pediatric patients. At the same time, the polymer coating 112 containing anti-infection components forms a leak-proof lumen, prevents mucosal tissue from embedding into the tube, reduces scaling, calcification and stone formation in the lumen, and can maintain effective support in the body for 6-12 months. After that, it gradually loses its support function as the memory metal wire 111 degrades. At the same time, there is an opaque marker 2 in the stent, which can be accurately inserted under X-rays.

[0042] In the case that the stent has not been completely degraded but needs to be removed in advance, the position-limiting anchor 122 can be clamped with a foreign body forceps and pulled out of the body, and the memory metal wire 111 will be removed in a linear shape.

[0043] A radiopaque marker 2 is installed inside the memory metal wire 111;

[0044] Notably, this stent utilizes a self-radially expanding metal tubular structure, but is smaller than traditional adult stents, with an expanded diameter of 6-8 Fr, making it suitable for the anatomical characteristics of the pediatric ureter. The tube wall is covered with a biodegradable polymer material containing anti-infective components, reducing the risk of infection and facilitating degradation. The ureteral stent is equipped with radiopaque markers 2 to enhance visibility under fluoroscopy: three radiopaque markers 2 are located at each end of the stent, and a separate radiopaque marker 2 is located on the stent retaining anchor 122. The delivery system is designed with a diameter of 4-6 Fr, which is thinner than the 10 Fr used in adults and more suitable for the ureteral diameter of pediatric patients. Once the stent is inserted into the narrowed section of the ureter, it is released and self-expands. During placement, the stent does not change its length, and the delivery system should be carefully removed from the body after placement.

[0045] Through the use of degradable materials, this stent can naturally degrade after completing its therapeutic function in the body, without the need for a second surgery to remove it, greatly reducing the psychological and physiological burden on pediatric patients.

[0046] The device further comprises a ureteral stent insertion mechanism 3 for inserting the pre-installed stent 1 into the ureter of a child. The ureteral stent insertion mechanism 3 comprises a child-specific thin-diameter cannula 31. The interior of the cannula 31 is connected to a Y-shaped connector 32. A connector 33 is provided on one side of the Y-shaped connector 32. The connector 33 is connected to one end of the cannula 31, and the pre-installed stent 1 is disposed on the surface of the cannula 31 at an end away from the connector 33.

[0047] It should be noted that for pediatric patients, the preparation steps before stent insertion need to be more cautious:

[0048] 1. Ensure that the knob (B) of the Y-connector 32 is tightly closed.

[0049] 2. Fill a syringe with 3-5ml of irrigation solution / saline (less than the adult amount).

[0050] 3. Connect the syringe to the flush port of the Y-connector.

[0051] 4. Slowly flush the system while ensuring that water can pass through the front end of the tube and the tapered end. Flushing the system is necessary for easy and smooth stent placement.

[0052] 5. After flushing, open the Y-connector 32 knob and ensure it remains fully open during stent placement.

[0053] For children, retrograde ureterography should be performed with diluted contrast agent to reduce renal burden. The site and length of the stricture, as well as the distance from the ureteral orifice, should be carefully identified, marked, and measured. Marking should be done with a radiopaque marker under fluoroscopy. If the patient has a renal catheter, ureterography can be performed antegradely. Measurements can be made using a pediatric ureteral catheter combined with endoscopy and fluoroscopy. A single-channel pediatric cystoscope (14-16 French) should be used to allow passage of a 4-6 French delivery system. A "retrograde system" with an appropriate stent length should be selected (the upper end of the stent should extend at least 5-8 mm above the stricture, smaller than the adult standard).

[0054] One end of the cannula 31 is provided with an outer tube visible black mark 4, and the outer tube visible black mark 4 is provided on the surface of the pre-installed stent 1;

[0055] Among them, the visible black mark 4 on the outer tube can indicate the position of the limit anchor 122 and the memory wire 111. Retrograde ureterography is performed to identify, mark and measure the location and length of the stenosis, as well as the distance from the ureteral orifice. The marking is completed with an external non-radiopaque marking pen under X-ray fluoroscopy. If the patient has a renal catheter, ureterography can be performed in an antegrade manner, and the measurement is completed using a ureteral catheter in combination with endoscopy and fluoroscopy.

[0056] The cannula 31 has a length of 12-18 cm and a circumference of 4-5 Fr, which is designed specifically for the diameter of the ureter of children and is smaller than the 10 Fr used for adults.

[0057] The apparatus further comprises a urethral stent insertion mechanism 5 for inserting the pre-installed stent 1 into the urethra. The urethral stent insertion mechanism 5 comprises a handle 51. An insertion tube 52 is provided on one side of the handle 51. The pre-installed stent 1 is provided at one end of the insertion tube 52. The handle 51 is also provided with a liquid injection port 53, a fixing clamp 54, an endoscope 55, a TeFrlon sheath button 56, a safety lock button 57, and a trigger 58.

[0058] It's important to note that for children, the bladder must be entered with extreme gentleness using an endoscope 55 (such as a pediatric cystoscope or ureteroscope) to minimize irritation to the urethral mucosa. When observing the urethra and ureters, use a low-pressure irrigation solution to avoid overdistension of the bladder. Directly viewing the endoscope 55 allows the physician to determine the opening and course of the urethra, guiding subsequent procedures. Handle 51 and insertion tube 52: The physician uses handle 51 to control the movement of insertion tube 52. The insertion tube 52 is equipped with a thinner guide wire (0.025-0.028 inches, thinner than the 0.035 inches used for adults) to guide the accurate placement of the stent. The TeFrlon sheath is used to protect the urethral wall of children and reduce damage. The button of the sheath is used to control the advancement and retreat of the sheath. The doctor pushes the stent along the guide wire to the stricture section of the urethra by operating the handle 51. During this process, the trigger 58 is needed to control the release of the stent. After the stent reaches the predetermined position, the fixing clamp 54 is needed to ensure the stability of the stent. The safety lock button 57 is used to lock the position of the stent to prevent it from shifting.

[0059] The insertion tube 52 has a length of 18-24 cm and a circumference of 5-6 Fr, which is suitable for the diameter of a child's urethra.

[0060] The connector 33 is configured as a Luer-type connector 33;

[0061] Among them, the Luer connector achieves rapid switching of fluid pipelines through the rapid connection and separation of the male Luer and the female Luer, greatly simplifying the management of the fluid system. Medical staff can quickly and easily connect or disconnect the pipeline without complicated operating steps, thereby improving work efficiency. The Luer connector has a compact structure and a reasonable design, ensuring the stability and reliability of the connection. The precise thread and sealing structure inside the connector effectively prevent the leakage of liquid or gas, ensuring the safe transmission of medical fluids. The Luer connector is usually made of high-quality materials such as ABS, PP, PC, and PVC. These materials have the characteristics of low density, light weight, good impact resistance, and wear resistance. At the same time, these materials also meet the requirements of biocompatibility testing, are harmless to the human body, and are not affected by water, inorganic salts, alkalis and various acids.

[0062] The limiting anchor 122 of the degradable and anti-infective pediatric ureteral covered stent of this device can limit the stent and reduce the displacement of the stent; the stent body is made of degradable memory metal wire 111, which can naturally degrade after completing the therapeutic function and does not require a second operation to remove; the polymer coating 112 contains anti-infective components and can continuously release antibacterial substances, effectively reducing the risk of urinary tract infection in children; the stent size is specially designed for children's ureters, which increases adaptability and comfort; at the same time, the pre-installed stent 1 is highly comfortable, can self-expand, and has uniform radial force, which increases the comfort of child patients.

[0063] The polymer coating 112, containing anti-infective ingredients, creates a leak-proof lumen, preventing mucosal tissue from embedding into the ureter, reducing intraluminal scaling, calcification, and stone formation, making it particularly suitable for pediatric patients. The stent's radiopaque marker 2, visible under X-rays, ensures accurate implantation. If the stent requires premature removal before complete degradation, the retaining anchor 122 can be grasped with a foreign body forceps and pulled outward. The memory wire 111 is then removed linearly, minimizing damage to the child's ureteral tissue.

[0064] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A degradable and anti-infection ureteral stent graft for children, characterized by: include: Pre-installed bracket (1); The pre-installed stent (1) comprises a stent body (11) which is tubular after being released and a limiting mechanism (12) for preventing it from falling off; The stent body (11) comprises a wavy degradable memory metal wire (111) and a polymer coating (112) containing anti-infective components covering the surface of the memory metal wire (111), the memory metal wire (111) is spirally wound, and the limiting mechanism (12) is arranged on one side of the stent body (11); The overall dimensions of the pre-installed stent (1) are specially designed for the diameter and length of a child's ureter.

2. The degradable and anti-infection pediatric ureteral stent graft according to claim 1, characterized in that: The limiting mechanism (12) comprises a metal wire connecting portion (121) fixedly mounted on one side of the memory metal wire (111), and a limiting anchor (122) for reducing stent migration is fixedly mounted on one side of the metal wire connecting portion (121).

3. The degradable and anti-infection pediatric ureteral stent graft according to claim 2, characterized in that: A radiopaque marker (2) is installed inside the memory metal wire (111).

4. The degradable and anti-infection pediatric ureteral stent graft according to claim 1, characterized in that: The polymer coating (112) is configured as a degradable polymer coating containing an antibiotic or antibacterial agent, and the degradable memory metal wire (111) is made of at least one material selected from magnesium alloy, zinc alloy, or iron alloy, and has a controllable degradation cycle of 6-12 months.

5. The degradable and anti-infection pediatric ureteral stent graft according to claim 1, characterized in that: The invention also includes a ureteral stent placement mechanism (3) for placing a pre-installed stent (1) into a child's ureter, wherein the ureteral stent placement mechanism (3) includes a child-specific thin-diameter cannula (31), the interior of the cannula (31) is connected to a Y-shaped connector (32), a connector (33) is provided on one side of the Y-shaped connector (32), the connector (33) is connected to one end of the cannula (31), and the pre-installed stent (1) is provided on the surface of the cannula (31) at an end away from the connector (33).

6. The degradable and anti-infection pediatric ureteral stent graft according to claim 5, characterized in that: One end of the cannula (31) is provided with an outer tube visible black marking portion (4), and the outer tube visible black marking portion (4) is provided on the surface of the pre-installed bracket (1).

7. The degradable and infection-resistant ureteral stent graft for children according to claim 6, characterized in that: The cannula (31) has a length of 12-18 cm and a circumference of 4-5 Fr, and is suitable for children of different ages.

8. The degradable and anti-infection pediatric ureteral stent graft according to claim 1, characterized in that: It also includes a urethral stent insertion mechanism (5) for inserting the pre-installed stent (1) into the urethra, the urethral stent insertion mechanism (5) including a handle (51), an insertion tube (52) provided on one side of the handle (51), the pre-installed stent (1) provided at the end of one end of the insertion tube (52), and a liquid injection port (53), a fixing clamp (54), an endoscope (55), a TeFrlon sheath button (56), a safety lock button (57) and a trigger (58) installed on the surface of the handle (51).

9. The degradable and anti-infection pediatric ureteral stent graft according to claim 8, characterized in that: The insertion tube (52) has a length of 18-24 cm and a circumference of 5-6 Fr.

10. The degradable and anti-infection pediatric ureteral stent graft according to claim 5, characterized in that: The connector (33) is configured as a Luer-type connector (33).

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