Biliary tract stent capable of being accurately released

Abstract

The invention discloses a biliary tract stent capable of being accurately released, which comprises a stent far end, a stent straight section and a stent near end which are connected in sequence, the number of layers of the stent is at least one, and the stent far end and the stent near end are made of materials with different colors. The number of layers of the stent is one, the materials of the stent far end, the stent straight section and the stent near end of the stent comprise but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon Pebax, and the material hardness of the stent far end, the stent straight section and the stent near end of the stent ranges from Shore 25D to Shore 72D. Compared with a traditional stent of the same specification, the biliary tract stent capable of being accurately released has the advantages that the cross sectional area of an inner cavity is larger by 40%-100%, meanwhile, the inner surface of the stent is made of the super-smooth material, a biological membrane and bile mud are not prone to being attached, and the smooth time of the biliary tract stent is greatly prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a biliary stent that can be precisely released. Background Art

[0002] In adults, the common bile duct and pancreatic duct merge within the intestinal wall to form the dilated bile-pancreatic ampulla (called the vater), which opens into the papilla of the descending duodenum. Surrounding the ampulla is a sphincter called the sphincter of 0ddi, which controls the discharge of bile and pancreatic juice and prevents reflux of duodenal contents. Biliary obstruction is a common digestive system disorder and can be categorized as either benign or malignant. Most cases are benign, typically due to gallstones, bile duct injury, recurrent cholangitis, or scarring strictures. Malignant obstruction is primarily caused by malignant tumors such as liver cancer, pancreatic cancer, and bile duct cancer. Biliary obstruction can lead to bile stasis, and long-term obstruction can lead to complications such as worsening liver function, gastrointestinal bleeding, and renal failure. In severe cases, it can be life-threatening, so prompt treatment is essential. Currently, the most common treatment is to place a biliary stent in the obstructed bile duct.

[0003] The distal end of the stent is placed in the common bile duct, and the proximal end is placed in the duodenum. Clinically, the double pigtail stent is expected to be deployed with extreme precision: the junction of the straight segment and the proximal pigtail is precisely located at the confluence of the common bile duct and duodenum. If part of the proximal pigtail is released into the common bile duct, the common bile duct opening will be over-dilated, allowing the contents of the duodenum to enter the sterile bile duct, leading to serious infection. If part of the straight segment of the double pigtail stent is released into the duodenum, the chance of stent migration is high.

[0004] To more accurately deploy double-pigtail biliary stents, some manufacturers place one or more black markers on the periphery of the junction between the straight and pigtail segments of the stent. However, in actual clinical practice, the markers are often covered by the contents of the duodenal tract and biliary excretion fluid, making it difficult to accurately deploy the stent.

[0005] The double pigtail biliary stent currently used in clinical practice has the following major defects 1. Precise stent deployment is difficult: Because the stent is pushed into the common bile duct via a stent delivery tube along a guidewire, it straightens during the delivery process, making it difficult for the physician to determine whether the straight segment has fully entered the common bile duct. The surface of the marked double-pigtail stent is easily covered with intestinal contents and biliary excreta, making precise deployment impossible. Therefore, most physicians use a black pen to blacken the proximal pigtail when deploying the double-pigtail stent, observing under direct endoscopic vision to determine if the black segment (proximal pigtail) is about to enter the common bile duct. However, during surgery, a small portion of the blackened segment inevitably enters the common bile duct. Because the biliary system is sterile, any black pen oil that enters the common bile duct can cause biliary infection.

[0006] 2. Stent Restenosis: Due to limitations in the bile duct structure and digestive endoscopy, conventional double-pigtail biliary stents have an outer diameter of up to 3 mm, corresponding to an inner diameter of only 1.9 mm. Such a small stent lumen is prone to re-clogging by bile duct stones, biofilm, and biliary sludge. Clinically, biliary stent replacement surgery is typically required every three months. Complications of such surgery include cholangitis and pancreatitis, significantly increasing patient suffering and the financial burden. Summary of the Invention

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a biliary stent that can be precisely released, comprising a stent distal end, a stent straight section and a stent proximal end connected in sequence, the stent having at least one layer, and the stent distal end and the stent proximal end being made of materials of different colors.

[0008] Preferably, the stent has one layer, and the materials of the distal end, straight section and proximal end of the stent include but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon Pebax, and the hardness of the materials of the distal end, straight section and proximal end of the stent is between Shore 25D and Shore 72D.

[0009] Preferably, the stent has two layers, namely, an outer layer of the stent and a super-slip layer on the inner surface of the stent; The materials available for the outer layer of the stent include but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon Pebax; Super-slip layer materials include, but are not limited to, polytetrafluoroethylene or high-density polyethylene; The hardness of the outer layer material of the distal end of the stent, the stent body and the proximal end of the stent is between Shore 25D and Shore 72D.

[0010] Preferably, the stent has three layers, namely, from the outside to the inside, it includes a stent outer layer, a middle reinforcement layer and a super-slip inner layer; The materials of the inner layer include but are not limited to polytetrafluoroethylene and high-density polyethylene; The middle layer includes a woven mesh structure or a spring structure woven from metal wires or polymer wires; The materials available for the thin metal wire include, but are not limited to, stainless steel, nickel-titanium memory alloy, cobalt-chromium alloy and tungsten; The materials available for the outer layer include but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon; The hardness of the outer layer material of the distal end of the stent, the straight section of the stent and the proximal end of the stent is between Shore 25D and Shore 72D.

[0011] Preferably, the stent has a diameter of 1-20 mm, a length of 10-200 mm, and a wall thickness of 0.1-2 mm; One or more side holes are formed on the side wall of the bracket; The shape of the side hole is circular or non-circular, and the diameter of the side hole is between 0.01-1 mm.

[0012] The biliary stent has very good visibility, and doctors can release the biliary stent accurately.

[0013] Preferably, the outer diameter of the distal end of the stent is equal to or smaller than the outer diameter of the proximal end of the stent; The distal end of the stent is formed into a circle or J shape by heat setting; The proximal end of the stent is formed into a circle or J shape by heat setting.

[0014] Preferably, the inner surface or the outer surface of the stent is covered with a drug coating, and the drug coating includes any one of antibacterial drugs, nano silver ions or anti-tissue proliferation drugs.

[0015] Compared with traditional stents of the same specifications, the inner cavity cross-sectional area is 40%-100% larger. At the same time, the inner surface of the stent of the present invention is made of ultra-smooth material, and biofilm and bile sludge are not easily attached. Such a biliary stent greatly prolongs the patency time and basically avoids the need for secondary surgery to replace the stent.

[0016] The present invention provides a biliary stent that can be precisely released and has the following beneficial effects: (1) The biliary stent can be released precisely. The biliary stent has very good visibility, and the doctor can release the biliary stent precisely.

[0017] (2) The precisely released biliary stent has an inner cavity cross-sectional area that is 40%-100% larger than that of conventional stents of the same specifications. Furthermore, the inner surface of the stent is made of ultra-slip material, which makes it difficult for biofilm and bile sludge to adhere. This significantly prolongs the patency time of the biliary stent and essentially avoids the need for a second surgery to replace the stent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of a single-layer biliary stent of the present invention; Figure 2 This is a partial schematic diagram of the three-layer biliary stent of the present invention.

[0019] In the figure: 1. proximal end of the stent; 2. straight section of the stent; 3. distal end of the stent; 4. outer layer of the stent; 5. middle layer of the stent; 6. inner layer of the stent. DETAILED DESCRIPTION

[0020] 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.

[0021] Example 1, see Figure 1 , the present invention provides a technical solution: The biliary stent is a single-layer polymer tube, and the available materials for the stent include silicone rubber, polyurethane, polyethylene, nylon or modified nylon Pebax. The distal pigtail 1 and the straight section 2 of the biliary stent are light-colored polymer tubes, and the proximal pigtail 3 of the biliary stent is a dark-colored polymer tube with the same inner diameter, outer diameter, material and the same distal end and stent body.

[0022] The light-colored polymer tube and the dark-colored polymer tube are welded together by heat melting.

[0023] Example 2, the present invention provides a technical solution: The biliary stent is a single-layer polymer tube. Available materials include silicone rubber, polyurethane, polyethylene, nylon, or modified nylon Pebax. The distal pigtail and straight section of the biliary stent are light-colored polymer tubes, while the proximal pigtail is a dark-colored polymer tube with the same inner diameter and material. The outer diameter of the proximal pigtail is greater than or equal to the outer diameter of the distal pigtail. The light-colored and dark-colored polymer tubes are welded together by hot melt.

[0024] Example 3, see Figure 2 , the present invention provides a technical solution: The biliary stent has a multi-layer structure: the outer layer 4 is made of the polymer materials used in conventional biliary stents, including but not limited to silicone rubber, polyurethane, polyethylene, nylon, or modified nylon; the middle layer 5 is a woven mesh or spring mesh, composed of filaments including but not limited to stainless steel, nickel-titanium shape memory alloy, cobalt-chromium alloy, tungsten, or other mechanically strong polymers; and the inner layer 6 is made of ultra-smooth polytetrafluoroethylene or high-density polyethylene. Because the woven mesh or spring mesh in the middle layer 5 enhances overall strength and flexural resistance, the outer layer 4 can be made of a polymer material with a thinner wall thickness. This means that, given the same outer diameter and mechanical properties, the inner diameter and lumen cross-sectional area of ​​the biliary stent in this embodiment are larger than those of conventional biliary stents. Furthermore, the ultra-smooth inner layer 6 of this embodiment resists the adhesion of gallstones, biofilm, and biliary sludge. These advantages ensure that the biliary stent in this embodiment remains patency for a longer period of time, minimizing the need for secondary surgery to replace the stent. The following table compares the inner and outer diameters and cross-sectional areas of a conventional single-layer biliary stent and the multi-layer biliary stent of this embodiment.

[0025] Specification testing: Bracket specifications Traditional stent outer diameter / inner diameter Cross-sectional area of ​​the lumen of traditional stents Outer diameter / inner diameter of the stent of the present invention Inner cavity / cross-sectional area of ​​the stent of the present invention 5F 1.67mm / 0.78mm 0.477mm^2 1.67mm / 1.17mm 1.074mm^2 is 1.1 times larger than the traditional 6F 2mm / 1mm 0.785mm^2 2.0mm / 1.4mm 1.539mm^2 is twice as large as the traditional 7F 2.33mm / 1.30mm 1.327mm^2 2.33mm / 1.70mm 2.269mm^2, 71% larger than traditional 8F 2.67mm / 1.60mm 2.01mm^2 2.67mm / 1.97mm 3.046mm^2, 55% larger than traditional 9F 3.0mm / 1.85mm 2.687mm^2 3.0mm / 2.2mm 3.799mm^2, 40% larger than traditional It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0026] 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 biliary stent capable of precise release, characterized by: The invention comprises a stent distal end, a stent straight section and a stent proximal end which are connected in sequence. The stent has at least one layer, and the stent distal end and the stent proximal end are made of materials of different colors.

2. The precisely releasable biliary stent according to claim 1, characterized in that: The stent has one layer, and the materials of the distal end, the straight section and the proximal end of the stent include but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon Pebax. The hardness of the materials of the distal end, the straight section and the proximal end of the stent is between Shore 25D and Shore 72D.

3. The precisely releasable biliary stent according to claim 1, characterized in that: The stent has two layers, namely, an outer layer of the stent and a super-slip layer on the inner surface of the stent; The materials available for the outer layer of the stent include but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon Pebax; The super-slip layer material includes but is not limited to polytetrafluoroethylene or high-density polyethylene; The hardness of the outer layer material of the distal end of the stent, the stent body and the proximal end of the stent is between Shore 25D and Shore 72D.

4. The precisely releasable biliary stent according to claim 1, characterized in that: The stent has three layers, namely, from the outside to the inside, it includes a stent outer layer, a middle reinforcement layer and a super-slip inner layer; The material of the inner layer includes but is not limited to polytetrafluoroethylene and high-density polyethylene; The intermediate layer comprises a woven mesh structure or a spring structure woven of metal wires or polymer wires; The materials available for the thin metal wire include but are not limited to stainless steel, nickel-titanium shape memory alloy, cobalt-chromium alloy and tungsten; The materials available for the outer layer include but are not limited to silicone rubber, polyurethane, polyethylene, nylon or modified nylon; The hardness of the outer layer material of the distal end of the stent, the straight section of the stent and the proximal end of the stent is between Shore 25D and Shore 72D.

5. The precisely releasable biliary stent according to claim 1, characterized in that: The stent has a diameter of 1-20 mm, a length of 10-200 mm, and a wall thickness of 0.1-2 mm; One or more side holes are formed on the side wall of the bracket; The side hole is circular or non-circular in shape, and the diameter of the side hole is between 0.01-1 mm.

6. The precisely releasable biliary stent according to claim 5, characterized in that: The outer diameter of the distal end of the stent is equal to or smaller than the outer diameter of the proximal end of the stent; The distal end of the stent is formed into a circle or J shape by heat setting; The proximal end of the stent is formed into a circle or J shape by heat setting.

7. The precisely releasable biliary stent according to claim 1, characterized in that: The inner surface or the outer surface of the stent is covered with a drug coating, and the drug coating includes any one of antibacterial drugs, nano silver ions or anti-tissue proliferation drugs.

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