A multi-side hole double drainage stent for EUS-HGS

Abstract

The present application relates to the technical field of medical devices, in particular to a multi-side-hole double-drainage stent for EUS-HGS, comprising a main body section, the two ends of the main body section being fixedly connected with end portions, and a plurality of side holes being formed in the side walls of the main body section and the end portions; the length of the main body section is 12-20 cm. The present application can improve the uniformity of the side hole diameter and distribution and thus improve the drainage effect by pre-setting the standardization side holes at the time of factory shipment and uniformly arranging the shape and position of the side holes.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a multi-port dual drainage stent for EUS-HGS. Background Technology

[0002] Endoscopic retrograde cholangiopancreatography (ERCP) is a routine procedure for treating conditions such as obstructive jaundice. However, ERCP may not be feasible in cases of papillary anatomical variations, tumor infiltration, or postoperative diversion. In these situations, endoscopic ultrasound-guided bile duct drainage (EUS-BD) becomes an alternative approach. Depending on the drainage route, EUS-BD mainly includes common bile duct-duodenal anastomosis (EUS-CDS), hepatogastric anastomosis (EUS-HGS), and antegrade stent placement (EUS-AGS).

[0003] In cases of distal bile duct obstruction, both EUS-CDS and EUS-HGS can establish a drainage channel between the common bile duct and the digestive tract. EUS-AGS, based on HGS, involves puncturing the intrahepatic bile duct and placing a stent antegradely into the bile duct, along with a hepatogastric stent, to achieve dual-channel drainage and reduce jaundice. When the stenosis is located at the porta hepatis or there is stenosis at the choledochoenterostomy, only EUS-HGS can be used. Most existing simple EUS-HGS methods can only drain the left hepatic bile duct or drain bile into the stomach, making it difficult to achieve adequate drainage of both bilobal bile ducts and restore the choledochoenterostomy pathway. The right hepatic bile duct often cannot be effectively drained simultaneously, limiting the drainage effect.

[0004] To facilitate communication between the left and right hepatic ducts or the bile duct and intestine, some clinicians employ a "bridging technique." This technique uses a double-pigtail plastic stent to create an internal drainage channel between the two systems, with the side holes manually trimmed. Commonly used double-pigtail stents include models 6102, 6103, and 6104 from Hobbs Medical. These stents typically do not have pre-set side holes at the factory; the surgeon must manually trim the stent during the procedure based on their experience to create these holes, followed by the insertion of a superselective guidewire to complete the drainage.

[0005] However, in practical applications, the aforementioned "intraoperative manual perforation" method is heavily influenced by the surgeon's experience. The lack of consistency in the diameter, number, and spatial distribution of the side holes can lead to uncertainties in drainage patency, drainage range, and stent stability. It also increases operation time and instrument handling steps. In summary, existing EUS-BD bridging stents still have room for improvement in side hole design and standardization. There is an urgent need to provide a stent solution suitable for endoscopic ultrasound guidance to improve the repeatability of side hole placement and the reliability of drainage pathway construction. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a multi-port dual-drainage stent for EUS-HGS, used for EUS-BD treatment in cases where ERCP is not feasible, specifically for stenosis of the hilar bile duct or biliary-enteric anastomosis. Furthermore, by pre-setting standardized side holes at the factory and uniformly arranging their shape and position, the stent improves the uniformity of the side hole diameter and distribution, thereby enhancing the drainage effect.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A multi-side hole dual drainage bracket for EUS-HGS includes a main body section, with end portions fixedly connected to both ends of the main body section. The end portions are all spiral-shaped. Several side holes are opened on the side walls of the main body section and the end portions. The length of the main body section is 12-20 cm, and the diameter of the main body section is 5-12 Fr.

[0008] The technical principles of the above solution are as follows:

[0009] The main segment, exceeding 10 cm in length, covers the left and right hepatic bile duct regions, meeting cross-regional drainage needs and providing a structural basis for simultaneous drainage of both bile ducts. The spiral ends enhance the stent's fixation within the bile ducts and digestive tract, preventing displacement and ensuring a stable drainage pathway. Several pre-designed side holes on the main segment's sidewalls, with their shape, diameter, and uniform distribution predetermined at the factory, eliminate the need for intraoperative manual trimming, ensuring unobstructed drainage and consistent coverage, while also shortening operation time and improving treatment reliability.

[0010] The above approach has the following beneficial effects:

[0011] 1. This solution improves the drainage effect by pre-setting standardized side holes at the factory and uniformly arranging the shape and position of the side holes.

[0012] 2. The stent design in this scheme adopts a relatively long double-pigtail structure and supports a bidirectional drainage mode where one end connects to the hepatic and bile ducts and the other end simultaneously connects to the gastric and intestinal cavities. Compared to the traditional EUS-HGS single stent, which can only drain the left lobe of the liver or the gastric cavity, and the EUS-AGS scheme, which requires a combination of hepatogastric and hepatic stents, this stent can achieve drainage of both lobe bile ducts or restoration of the bile-enteric pathway with a single stent, reducing the number of stents required and lowering the risk of complications such as bile leakage and bleeding.

[0013] 3. The double pigtail structure of this solution can enhance anchoring stability and effectively prevent the support from shifting.

[0014] Furthermore, the shape of the side hole includes one of the following: circular, star-shaped, and polygonal.

[0015] Beneficial effects: The shape of the side hole can be changed to different geometric shapes, thereby improving the visibility of the side hole under X-ray and thus improving the accuracy of the bracket installation position.

[0016] Furthermore, developing bands are provided around the side holes, and the shapes of the developing bands and side holes are adapted to each other.

[0017] Beneficial effects: The geometric fit between the imaging zone and the side hole allows for further identification of the side hole location during surgery via X-ray or endoscopic ultrasound, helping doctors confirm whether the side hole corresponds to the bile duct branch opening.

[0018] Furthermore, the developing tape is a non-metallic high-density developing filler.

[0019] Beneficial effects: Non-metallic high-density imaging fillers are easy to integrate with the scaffold material and have high biocompatibility. Both types of materials can ensure that the side holes are clearly visible under imaging, which can improve the identification of the scaffold and the accuracy of scaffold positioning.

[0020] Furthermore, the non-metallic high-density developing filler includes one of barium sulfate and bismuth oxide.

[0021] Beneficial effects: Non-metallic high-density imaging fillers have high biocompatibility.

[0022] Furthermore, shape memory alloy wires are embedded in the ends.

[0023] Beneficial effects: The shape memory alloy wire has good elasticity and toughness, which can adapt to the peristalsis of the bile duct or changes in the patient's position, reduce the pressure damage of the stent on the bile duct wall, and maintain the spiral structure shape to ensure long-term anchoring effect.

[0024] Furthermore, the shape memory alloy wire is made of nickel-titanium alloy material, and Fe3O4 nanoparticles are embedded within the shape memory alloy wire.

[0025] Beneficial effects: Fe3O4 nanoparticles are superparamagnetic. After surgery, the shape memory alloy wire can be locally heated to the phase transition temperature by irradiation with a low-frequency magnetic field outside the body. This allows for fine adjustment of the spiral shape at the end. When the stent needs to be switched from dual drainage to single drainage, the magnetic field triggers the end to contract, pulling the pig tail segment of the stomach into the liver without the need for secondary endoscopic intervention, thus reducing patient pain and the risk of complications.

[0026] Furthermore, the end length is 5–8 cm.

[0027] Beneficial effects: The longer end can form a longer spiral anchoring segment in the stomach, intestine or bile duct, while also being adapted to the effect of dual drainage.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] Figure 1 This is an isometric view of the multi-side hole dual drainage bracket for EUS-HGS according to the present invention.

[0030] Figure 2 for Figure 1 Enlarged view of part A in the middle.

[0031] Figure 3 This is a diagram showing the placement position of the multi-port dual-drainage stent of the present invention in EUS-HGS during the EUS-HGS procedure.

[0032] Figure 4 This is a diagram showing the placement position of the multi-port dual-drainage stent of the present invention in EUS-HGS during EUS-CDS procedure.

[0033] The reference numerals in the accompanying drawings include: 1. Main body section; 2. End; 3. Side hole. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] The following detailed description illustrates the specific implementation method:

[0038] Example 1:

[0039] As attached Figure 1 and Figure 2The diagram shows a multi-sided, dual-drainage stent for EUS-HGS, comprising a main body segment 1, with end portions 2 integrally formed at both ends of the main body segment 1. Both end portions 2 are helical. Several side holes 3 are formed on the sidewalls of both the main body segment 1 and the end portions 2. The main body segment 1 has a length of 12–20 cm and a diameter of 5–12 Fr. The end portions 2 have a length of 5–8 cm. In this embodiment, the main body segment 1 is tubular, with an axial length of 15 cm and an inner diameter of 8 mm; the pigtail-shaped helical end portions 2 located at both ends of the main body segment 1 each have an axial length of 5 cm.

[0040] In this embodiment, the side holes 3 are arranged in an array. Specifically, the diameter of the side holes 3 is 2.8 mm, and the pitch (center distance) between adjacent side holes 3 is 15 mm in the axial direction of the main body segment 1. A side hole 3 is opened at 30° intervals in the circumferential direction of the main body segment 1, meaning there are a maximum of 12 side holes 3 on the same cross-section. This arrangement ensures that the drainage range covers multiple branches of the bilateral intrahepatic bile duct system.

[0041] Furthermore, no side holes 3 are provided within 10 mm of the end connection at both ends of the main body segment 1, forming a hole-free safety segment. This design effectively prevents bile or digestive juices from leaking into the liver parenchyma or abdominal cavity through the terminal side hole 3, reducing the risk of bile leakage and peritonitis.

[0042] like Figure 3 As shown, during stent placement, one end 2 of the stent is placed within the dilated left intrahepatic bile duct branch, the main body 1 passes through the liver parenchyma and stomach wall with a length of approximately 3-5 cm, and the other end 2 is placed in the stomach cavity. The pre-designed side holes 3 ensure that bile from the left intrahepatic bile duct, the right intrahepatic bile duct (the bridging length can be adjusted to 2-4 cm via bridging technology), and the common bile duct can all be smoothly drained into the digestive tract through the stent, achieving adequate drainage of the bilobed bile ducts under a single stent. The spiral end 2 provides a stable anchorage, preventing the stent from slipping and ensuring long-term stent stability.

[0043] like Figure 4 As shown, in another embodiment, when the stent of the present invention is inserted, one end 2 of the stent is placed in the stomach cavity (insertion depth of about 2-3 cm), the main body segment 1 passes through the liver parenchyma and the stomach wall (passage length of about 4-6 cm), and the other end 2 crosses the narrow choledochoenterostomy and is placed directly in the jejunal lumen (insertion depth of about 3-4 cm).

[0044] In this placement mode, the stent bypasses the original choledochoenterostomy site, which has become ineffective or narrowed.

[0045] The bile drainage pathway is as follows: intrahepatic bile duct → side hole 3 on the main segment 1 → side holes 3 at both ends of the stent → intestine and stomach. This new pathway effectively relieves obstructive jaundice caused by anastomotic stenosis.

[0046] The pre-designed, evenly distributed side holes 3 ensure multiple drainage inlets and outlets in both the intrahepatic bile duct and intestinal segments, greatly reducing the risk of stent failure due to blockage of a single outlet by mucus or food residue, and ensuring the patency and reliability of drainage.

[0047] Combination Figure 4 As shown, in this embodiment, by pulling the intestinal end 2 of the stent, the stent is converted from a double-drainage state to a single-drainage state. After pulling, the pig tail end 2 at the stomach end will be directly pulled into the liver, avoiding the placement of a stent between the liver and stomach, thereby simplifying the operation and reducing potential complications between the liver and stomach.

[0048] As attached Figure 2 As shown, a contrast-enhancing band is provided around each side hole 3. The shape of the contrast-enhancing band is adapted to the side hole 3. The contrast-enhancing band is a non-metallic high-density contrast-enhancing filler. In this embodiment, the non-metallic high-density contrast-enhancing filler is one of barium sulfate 10-25wt% and bismuth oxide 5-15wt%. The radial distance between the inner edge of the contrast-enhancing band and the corresponding edge of the side hole 3 is 0.3-1.0 mm, so as to achieve visual identification of the position of the side hole 3 under X-ray or fluoroscopy. This design can ensure that the doctor can identify the position of the side hole 3 through the contrast-enhancing band under X-ray guidance, and can accurately locate the position of the end 2 and the main body segment 1, reducing the uncertainty in the surgical process. At the same time, the non-metallic high-density contrast-enhancing filler has high safety.

[0049] In this embodiment, the formulation and performance parameters of the non-metallic high-density developing filler are shown in Table 1. Table 1 is a table of formulation and performance parameters of the non-metallic high-density developing filler:

[0050]

[0051] Table 1

[0052] The side hole 3 can be circular, star-shaped, or polygonal. In this embodiment, the side hole 3 is circular. In other embodiments, the side hole 3 can be a regular hexagon (1.6 mm side length). This geometric shape of the side hole 3, combined with a radiopaque tape that matches its shape, further enhances the visibility and recognizability of the side hole 3 under X-rays, thereby improving the accuracy of the installation position of the end 2 and the main body segment 1.

[0053] Example 2:

[0054] As attached Figure 1 As shown, the difference from Example 1 is that the ends 2 are all embedded with shape memory alloy wires, which are made of nickel-titanium alloy material and contain Fe3O4 nanoparticles.

[0055] In this embodiment, the phase transformation temperature (Af point) of the shape memory alloy wire ranges from 28℃ to 32℃. The shape memory alloy wire is made of Nitinol material, with a chemical composition of 50.8 at% nickel and 49.2 at% titanium. During the alloy melting process, 15 vol% of Fe3O4 nanoparticles (average particle size 20 nm) are uniformly incorporated and distributed in the Nitinol alloy matrix. At room temperature (below the Af point), the shape memory alloy wire is in the martensitic phase and has a soft texture.

[0056] When conventional stents are inserted into the body, their spiral tail ends are constrained and straightened during delivery. After the stent is pushed out of the delivery sheath, it relies on the elasticity of the material (such as silicone or ordinary polymers) to restore its spiral curled shape. However, during insertion, the stent tip needs to pass through the endoscopic forceps channel and be subjected to varying degrees of traction, pushing, and torsion within the body. If the force and angle of traction or pushing are improper during the procedure, the elastic material can easily undergo plastic deformation exceeding its elastic limit. Once this plastic deformation occurs, the stent tip will be difficult to fully restore to the preset ideal spiral shape, potentially exhibiting incomplete curling, abnormal angles, or even partially straightening. An incomplete spiral structure cannot provide sufficient radial support to form a stable fit with the tissue, significantly increasing the risk of stent displacement.

[0057] After the stent of the present invention is straightened at end 2 and positioned at the target intrahepatic bile duct, an alternating magnetic field with a frequency of 80-120 kHz and a field strength of 8-12 kA / m is applied through an external device and continuously irradiated for 3-5 minutes.

[0058] Embedded Fe3O4 nanoparticles, under the influence of an alternating magnetic field, convert magnetic energy into heat energy, causing the local temperature of the shape memory alloy wire to rise to a maximum of 37°C within a short period, triggering the Af point. This triggers an austenitic phase transformation in the shape memory alloy wire, at which point the wire hardens and returns to its original helical shape. The shape memory alloy wire then causes end 2 to curl from a straightened state into a pre-set helical shape, thereby achieving stable anchoring and significantly reducing the risk of plastic deformation and incomplete shape recovery due to improper operation. This provides reliable and consistent anchoring performance for the stent, improving the success rate and safety of the surgery. Simultaneously, when the stent is pulled from a dual-drainage state to a single-drainage state, the above magnetic field irradiation steps are repeated.

[0059] The phase transition temperature range of shape memory alloy wires is shown in Table 2. Table 2 is a table of phase transition temperature ranges for shape memory alloy wires:

[0060]

[0061] Table 2

[0062] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A multi-side-hole dual-drainage stent for EUS-HGS, comprising a main body section (1), with end portions (2) fixedly connected to both ends of the main body section (1), the end portions (2) being spiral-shaped, and a plurality of side holes (3) being opened on the sidewalls of both the main body section (1) and the end portions (2), characterized in that The main body segment (1) is 12-20 cm long and has a diameter of 5-12 Fr. The side hole (3) is surrounded by a developing band. The shape of the developing band and the side hole (3) are compatible. The developing band is a non-metallic high-density developing filler. The ends (2) are all embedded with nickel-titanium alloy shape memory alloy wires, which are embedded with Fe3O4 nanoparticles. The austenitic phase transformation end temperature Af of the shape memory alloy wires is 28-32℃. The shape memory alloy wire comprises a nickel-titanium alloy matrix and 15 vol% Fe3O4 nanoparticles uniformly distributed in the nickel-titanium alloy matrix, wherein the average particle size of the Fe3O4 nanoparticles is 20 nm. When the end (2) is straightened and reaches the target intrahepatic bile duct, an alternating magnetic field with a frequency of 80-120 kHz and a field strength of 8-12 kA / m is applied by an external device and continuously irradiated for 3-5 minutes. Under the action of the alternating magnetic field, the Fe3O4 nanoparticles convert magnetic energy into heat energy, causing the local temperature of the shape memory alloy wire to rise to a maximum of 37°C in a short time, triggering the Af point to cause the shape memory alloy wire to undergo an austenitic phase transformation, changing from soft to hard and restoring to the original spiral shape. The shape memory alloy wire then drives the end (2) to curl from the straightened state into a preset spiral shape. When the stent is pulled from the dual-drainage state to the single-drainage state, repeat the above steps of irradiating the magnetic field.

2. The multi-sided dual-drainage stent for EUS-HGS according to claim 1, characterized in that, The shape of the side hole (3) includes one of the following: circular, star-shaped and polygonal.

3. The multi-sided dual-drainage stent for EUS-HGS according to claim 2, characterized in that, The developing tape is a non-metallic high-density developing filler.

4. The multi-sided dual-drainage stent for EUS-HGS according to claim 3, characterized in that, Non-metallic high-density developing fillers include one of barium sulfate and bismuth oxide.

5. The multi-sided dual-drainage stent for EUS-HGS according to claim 4, characterized in that, The length of the end (2) is 5 to 8 centimeters.

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