Self-expanding tissue lumen stent with enhanced drainage function

Abstract

The present disclosure provides a tissue lumen stent having an elongated tubular configuration and a shortened configuration. In the shortened configuration, the upstream end, the downstream end, or both the upstream and downstream ends are radially expanded flange and / or flared structures, while the region therebetween is generally cylindrical. The upstream flange structure has a greater maximum transverse dimension, axial width, and / or axial radius than the downstream flange structure, and may include a tapered portion having an axial length at least as long as the maximum diameter of the saddle region when the body is in the shortened configuration.

Description

Technical Field

[0001] This application generally relates to medical methods and devices. More specifically, the present disclosure relates to a luminal stent for maintaining the patency of a lumen in a medical procedure and a method of using the same.

Background Art

[0002] Tissue lumen stents are often used in medical procedures to maintain the patency of a lumen. Typically, a tissue lumen stent has a body with an upstream end, a downstream end, and a central region between these upstream and downstream ends. As a medical procedure, there can be provided one including (a) a step of accessing a patient's biliary system using an endoscope, and (b) a step of deploying a tissue lumen stent into the patient's biliary system such that the tissue lumen stent contacts a lumen within the patient's biliary system, such as the common bile duct, pancreatic duct, or hepatic duct.

Summary of the Invention

[0003] Each embodiment described herein provides a tissue lumen stent having features for improving, enhancing, or facilitating drainage. Generally, the tissue lumen stent has an elongated tubular configuration and a shortened configuration. In the shortened configuration, the upstream end, the downstream end, or both the upstream and downstream ends are a radially expanded flange structure and / or flare structure, while the region between them is generally cylindrical.

[0004] In some cases, when the stent is in a shortened configuration, the upstream flange structure may have a larger maximum lateral dimension, axial width, and / or axial radius than the downstream flange structure, and may include an inclined portion having an axial length at least the same as the maximum diameter of the saddle region of the body in the shortened configuration. On the other hand, some embodiments are characterized in that the downstream flange structure has a larger maximum lateral dimension, axial width, and / or axial radius than the upstream flange structure. Alternatively or additionally, the upstream flange structure may include a distal opening having a diameter larger than the maximum inner diameter of the saddle region when the body is in a shortened configuration. In certain embodiments, the body includes a covered mesh, and in some cases may include both a covered mesh and an uncovered mesh. Also, some embodiments include a covering or membrane, which covers at least the cylindrical saddle region of the stent, and optionally, either or both of the upstream flange structure and / or the downstream flange structure.

[0005] In some embodiments, the present disclosure can be embodied as a stent. For example, the stent includes a body comprising an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, the upstream end of the body extends into an upstream structure and the downstream end of the body extends into a flange structure. The body comprises a cylindrical saddle region positioned between the upstream structure and the flange structure, and further comprises a channel extending spirally around the outer circumference of the body, the channel being formed on the outside of the body and also reflected on the inside of the body.

[0006] Alternatively or additionally, in any of the above-described embodiments of the stent, the channels have a constant pitch along the longitudinal direction of the body. Alternatively or additionally, in any of the above-described embodiments of the stent, the channel pitch increases along the longitudinal direction of the body.

[0007] Alternatively or additionally, in any of the above embodiments of the stent, the pitch increases along the longitudinal direction of the body from the upstream end to the downstream end. Alternatively or additionally, in any of the above embodiments of the stent, the channel width may be wider at the upstream end of the body than at the downstream end of the body.

[0008] Alternatively or additionally, in any of the above embodiments of the stent, the channel width may be wider at the downstream end of the body than at the upstream end of the body. Alternatively or additionally, in any of the above-described embodiments of the stent, the upstream structure includes a flange or flare.

[0009] In some embodiments, the present disclosure can be embodied as a stent. For example, the stent comprises a body having an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, the upstream end of the body extends into an upstream structure and the downstream end of the body extends into a flange structure. The body comprises a cylindrical saddle region positioned between the upstream structure and the flange structure, and further comprises a covering that extends to the downstream end of the body and the cylindrical saddle region. The upstream structure also comprises a plurality of anti-movement fins positioned on its outer surface.

[0010] Alternatively or additionally, in any of the above-described embodiments of the stent, the plurality of anti-movement fins comprises wire fins arranged to flare outward from the upstream structure.

[0011] Alternatively or additionally, in any of the above embodiments of the stent, the plurality of anti-movement fins are provided with tips facing toward the downstream end of the body. Alternatively or additionally, in any of the above embodiments of the stent, at least one of the plurality of anti-movement fins may have a tip facing toward the downstream end of the body, and at least another of the plurality of anti-movement fins may have a tip facing toward the upstream end of the body.

[0012] Alternatively or additionally, in any of the above-described embodiments of the stent, the upstream structure may include a flare. In some embodiments, the present disclosure can be embodied as a stent. For example, the stent comprises a body comprising an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, the upstream end of the body expands into an upstream flange structure, and the downstream end of the body expands into a downstream flange structure. The body comprises a cylindrical saddle region positioned between the upstream and downstream flange structures, the cylindrical saddle region having a curve along the longitudinal direction of the body.

[0013] Alternatively or additionally, in any of the above embodiments of the stent, the cylindrical saddle region may have another curve along the axial direction of the body. Alternatively or additionally, in any of the above embodiments of the stent, the curve is either closer to the upstream flange structure than to the downstream flange structure, or closer to the downstream flange structure than to the upstream flange structure.

[0014] In some embodiments, the present disclosure can be embodied as a method. For example, a method for treating a patient comprising the steps of accessing the patient's biliary system using an endoscope and deploying a stent within the patient's biliary system. The stent comprises a body having an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, the upstream end of the body expands into an upstream structure and the downstream end of the body expands into a flange structure. The body comprises a cylindrical saddle region positioned between the upstream structure and the flange structure, and further comprises a channel extending spirally around the body, the channel being formed on the outer surface of the body and also reflected on the inner surface.

[0015] Alternatively or additionally, in embodiments of any of the methods described above, the channels may have a constant pitch along the longitudinal direction of the body. Alternatively or additionally, in embodiments of any of the methods described above, the channel pitch increases along the longitudinal direction of the body.

[0016] Alternatively or additionally, in embodiments of any of the methods described above, the pitch increases along the longitudinal direction of the body from the upstream end to the downstream end. Alternatively or additionally, in embodiments of any of the methods described above, the width of the channel is wider at the downstream end of the body than at the upstream end of the body.

[0017] To facilitate the identification of any element or operation description, the most significant digit of the reference number refers to the drawing number in which the element is first shown.

Brief Description of the Drawings

[0018] [Figure 1A] A diagram showing the biliary tract system. [Figure 1B] A diagram showing the state in which the stent 120 is arranged in the biliary tract system of FIG. 1A. [Figure 2A] A diagram showing the stent 200 according to at least one embodiment of the present disclosure. [Figure 2B] A diagram showing another detail of the stent 200. [Figure 3] A diagram showing the stent 300 according to at least one embodiment of the present disclosure. [Figure 4A] A diagram showing the stent 400a according to at least one embodiment of the present disclosure. [Figure 4B] A diagram showing the stent 400b according to at least one embodiment of the present disclosure. [Figure 5A] A diagram showing the stent 500a according to at least one embodiment of the present disclosure. [Figure 5B] A diagram showing the stent 500b according to at least one embodiment of the present disclosure. [Figure 6A] A diagram showing the stent 600a according to at least one embodiment of the present disclosure. [Figure 6B] A diagram showing the stent 600b according to at least one embodiment of the present disclosure. [Figure 7] A diagram showing the biliary tract system of a patient with a stent arranged therein. [Figure 8A] A diagram showing the stent 800a according to at least one embodiment of the present disclosure. [Figure 8B] A diagram showing the stent 800b according to at least one embodiment of the present disclosure. [Figure 8C] A diagram showing a stent 800c according to at least one embodiment of the present disclosure. [Figure 8D] A diagram showing a stent 800d according to at least one embodiment of the present disclosure. [Figure 9A] A diagram showing the biliary system of a patient. [Figure 9B] A diagram showing the biliary system of FIG. 9A in another detail.

Mode for Carrying Out the Invention

[0019] In the present disclosure, the terms anterograde, retrograde, downstream, upstream, proximal, distal, lower, upper, inferior, and superior are used to indicate various directions. Unless the context clearly indicates otherwise, the terms anterograde, downstream, proximal, lower, and inferior generally refer to the direction along the flow of fluid and are used synonymously to indicate the direction towards the surgeon along the device and instrument. Conversely, the terms retrograde, upstream, distal, upper, and superior generally refer to the direction against the flow of fluid and are used synonymously to indicate the direction away from the surgeon along the device and instrument. However, it should be noted that this nomenclature is not intended to limit the scope of the invention but is defined to clarify the following description. The exemplary embodiments disclosed herein focus on insertion and placement in the retrograde direction, but the disclosed methods, systems, and devices may be arranged in the anterograde direction in some environments. In such situations, "upstream" and "downstream" may refer to opposite meanings.

[0020] As stated above, this disclosure describes an expandable stent used in the biliary system of a patient. Therefore, this specification provides a description of the biliary system. Bile, which is necessary for the digestion of food, is secreted by the liver and delivered to the left hepatic duct 102 and the right hepatic duct 104 via bile-carrying passages. These two hepatic ducts merge to form the common hepatic duct 106. After leaving the liver, the common hepatic duct 106 merges with the cystic duct 108, which extends from the gallbladder 110, which stores bile, to form the common bile duct 112. The common bile duct 112 further merges with the pancreatic duct 114, which extends from the pancreas, and supplies bile, pancreatic juice, and insulin to the descending portion of the duodenum 116 via the ampulla of Vater 118. A sphincter known as the sphincter of Oddi is located where the ampulla of Vater 118 opens into the duodenum 116 and prevents the backflow of substances from the duodenum 116 into the common bile duct 112.

[0021] The growth of tumors, hyperplasia, pancreatitis, or other strictures within or around the biliary tract described above can obstruct or block the flow of fluid from the liver, gallbladder, and / or pancreas to the duodenum. To mitigate the effects of stricture, it may be necessary to place a stent in part of the biliary tract. Stents can be placed endoscopically. One procedure for stent placement is endoscopic retrograde cholangiopancreatography (ERCP). ERCP is a technique that uses endoscopy and fluoroscopy to diagnose and treat specific problems in the biliary or pancreatic duct system. This procedure involves inserting an endoscope down the esophagus, through the stomach, into the duodenum, and then inserting various accessories through the endoscopic instrument channel to reach the biliary or pancreatic duct system via the ampulla of Vater. Alternatively, a special thin endoscope, sometimes called an oral cholangioscope, can be inserted directly into the bile duct or pancreatic duct.

[0022] Thus, stents currently deployed by ERCP are used to facilitate the drainage of bile through the biliary system. Drainage is a commonly desired feature of self-expanding stents, allowing for residual drainage from secondary sources. This disclosure describes and illustrates several self-expanding stents with improved drainage capabilities or characteristics.

[0023] Figure 1B shows an exemplary biliary stent 120 placed at the lower end of the common bile duct 112. In this configuration, the stent 120 may be used to treat papillary stricture. In other embodiments, the stent 120 may be designed to be longer to bridge a bile duct stricture further upstream. The stent 120 comprises a downstream end 122 projecting into the duodenum 116 and an upstream end 124 extending into the common bile duct 112. The stent 120 is shown generally radially expanded and axially shortened to continuously contact the wall of the common bile duct 112 along its entire length or at least in several places.

[0024] Figure 2A shows a stent 200 according to at least one embodiment of the present disclosure. The stent 200 comprises a body 202 having a generally tubular structure. The body 202 may be formed from a woven filament braid. The filaments are typically metal wires, more typically nickel-titanium or other metal wires having superelastic or shape memory properties. Alternatively, when elasticity is not so important, the filaments may be formed from polymer materials such as polypropylene, polyethylene, polyester, nylon, or PTFE. In some cases, bioabsorbable or biodegradable materials, typically biodegradable polymers such as poly-L-lactic acid (PLLA), may be used.

[0025] The body 202 has both an elongated tubular configuration (when the stent is delivered) and a shortened configuration (when deployed), in which the downstream and upstream ends of the body expand radially (as the body is shortened). One or both ends of the body 202 may expand into a flange 204 (e.g., a double-walled flange structure). Such a “double-walled flange structure” may be formed when a portion of the body moves inward (towards the center). This portion of the body is usually the outermost part, but optionally a predetermined portion located inward from the end. The portion of the body moves such that a pair of adjacent body segments of the portion are drawn towards their bases in order to expand radially with a curved centerline or topline, into a pair of adjacent annular rings defining a flange 204 having a double-walled flange structure. After shortening and deployment of such a double-walled flange structure, the body 202 may further have a cylindrical saddle region 206 formed between the flanges 204.

[0026] Furthermore, the main body 202 may have channels 208 that extend spirally around the main body 202 and the cylindrical saddle region 206. The channels 208 may run along the entire length of the stent 200. Note that Figure 2A shows the external appearance of the stent 200, while Figure 2B shows cross-sectional views of the stent 200 at two locations along its longitudinal direction, showing the internal lumen 210 of the stent 200. As can be seen from these figures, the channels 208 that are present on the outer surface of the stent 200 are also transferred to the internal lumen 210. As described herein, the stent 200 may be formed as a single-walled braided device. In this way, the channels 208 that extend along the entire length of the stent 200 are present on both the outer and inner surfaces of the main body 202, thereby facilitating the flow of bile (or other substance) through the stent 200. As shown in the figure, channel 208 can be defined from the distal end of stent 200 to the proximal end of stent 200.

[0027] When the stent 200 is formed from a shape memory alloy wire such as nitinol or eligliloy, the wire may have a relatively small diameter. The diameter is typically in the range of 0.001 inches (approximately 0.0254 mm) to 0.02 inches (approximately 0.508 mm), and generally in the range of 0.002 inches (approximately 0.0508 mm) to 0.01 inches (approximately 0.254 mm). The braid may contain a minimum of 10 to a maximum of 200 metal wires. More commonly, it may contain 20 to 200 metal wires. In an exemplary case, the wire is circular, with a diameter ranging from 0.003 inches (approximately 0.0762 mm) to 0.007 inches (approximately 0.1778 mm), and the total number of wires is 24 to 60. The wire can be braided into a tubular shape by conventional techniques. The tubular shape may also be heat-treated to impart the desired shape memory properties. Typically, the braided tube is formed into a desired final configuration (e.g., after deployment) having flanges at each end. Such a flanged configuration may then be heat-set or formed within the braid so that the stent assumes a shortened configuration with flanges at each end when no radial constraining or axial stretching forces are applied. Such a shortened storage configuration allows the stent to be delivered in a constrained configuration (e.g., a radially or axially stretched configuration) and then released from constraint so that the body 202 assumes a desired flanged configuration (e.g., flange 204) at the target site.

[0028] However, in an alternative embodiment, the woven filament braid can be heat-fixed to an elongated tubular configuration and transitioned to a shortened flanged configuration by applying an axial compressive force. Such axial compression compresses the flange and expands radially, while also enabling controllable and adjustable shortening, allowing the stent to be adjusted to a desired length. According to this embodiment, the woven filament braid is heat-fixable to an expanded configuration and includes a mechanism for mechanically shortening the stent beyond its normal fully expanded configuration, allowing the stent to be automatically or manually adjusted to the length of stenosis. The shortened structure and flange can be formed by providing sleeves, tubes, rods, filaments, tethers, springs, elastic members, etc. These cause the formation of the shortened structure and flange by applying a spontaneous or applied force to the tube. Optionally or additionally, the body 202 may have weakened and strengthened regions, or be otherwise modified, so that a desired flange shape is formed when a force causing axial shortening is applied.

[0029] The stents described herein (e.g., stent 200) can be adapted to be delivered by a delivery device, typically by an endoscopic delivery catheter. The catheter usually has a small diameter ranging from 1 mm to 8 mm, and generally from 2 mm to 5 mm. Thus, the elongated tubular configuration of the body 202 usually has a diameter smaller than the diameter of the catheter, generally ranging from 0.8 mm to 7.5 mm, and more commonly from 0.8 mm to 4.5 mm. The flange structure in such a configuration is greatly expandable, generally ranging from 3 mm to 70 mm, and more commonly from 5 mm to 40 mm. Various stents with different lengths for use in stenosis at different sites may be provided, for example, in the form of a kit. In some embodiments, the total length of the stent in its fully expanded / unfolded state is 7 cm, 9 cm, and 11 cm. In other embodiments, the total length is 6 cm, 8 cm, and 10 cm. In yet another embodiment, the stent is between 1 cm and 6 cm. The cylindrical saddle region 206 of the stent 200 often does not increase in diameter during deployment, but its diameter can optionally increase from 2 mm to 50 mm, and more commonly from 5 mm to 12 mm. The lumen or passage through the deployed stent 200 can typically have a variety of diameters, if present, ranging from a minimum of 0.2 mm to a maximum of 40 mm. More commonly, it is 1 mm to 20 mm in diameter, and more typically, slightly smaller than the expanded outer diameter of the cylindrical saddle region 206. The body length can vary considerably. Typically, in an elongated tubular configuration, the body length ranges from 7 mm to 200 mm, and usually from 12 mm to 70 mm. When deployed, the body 202 can be shortened. Typically, it is shortened by at least 20%, more typically by at least 40%, and often by more than 70%. Thus, the shortened length typically ranges from 2 mm to 80 mm, and usually from 30 mm to 60 mm.

[0030] The body 202 of the stent 200 may consist solely of woven filament braiding without any other coverings or layers. However, in other cases, the stent 200 may further include a membrane or other covering formed over at least a portion of the body 202. Often, the membrane is intended to prevent or inhibit growth into the tissue so that the device can be removed after being implanted for several weeks, months, or longer. Suitable membrane materials include polytetrafluoroethylene (PTFE), porous PTFE (EPTFE), silicone, polypropylene, urethane polyether block amide (PEBA), polyethylene terephthalate (PET), polyethylene, C-Flex® thermoplastic elastomer, Krator® SEBS and SBS polymers, etc.

[0031] Such a membrane may be formed to cover all or only a portion of the body 202 of the stent 200, or to cover the entire outside or inside of the body 202. The membrane is typically elastomerized to conform to the body 202 in both elongated tubular and shortened configurations. Optionally, the membrane may be formed to cover only the central portion of the cylindrical saddle region 206. In this case, the membrane does not need to be flexible when the central portion of the cylindrical saddle region 206 does not expand radially.

[0032] The covering or membrane inhibits internal tissue growth into the gaps of the wire mesh, minimizing fluid leakage when the stent is placed. Inhibiting internal tissue growth improves the stent's removability. In contrast to vascular stents, which are typically not designed for movement or retrieval, the stents described herein are foldable and designed for removal and retrieval. Furthermore, these stents typically do not contain barbs or other sharp protrusions used for permanent fixation to surrounding tissues in other types of stents.

[0033] Different portions of a stent may or may not be covered depending on the specific application. In some embodiments, one end of the stent may have an uncovered portion. In some embodiments, any of the stents disclosed herein may include a cover on one end of the stent. The cover may be provided on the flanged end or the unflanged end of the stent. For example, when one end of the stent is deployed in the liver and the other end in the stomach, the end of the stent located in the liver has a cylindrical saddle region 206 and is uncovered, while the end in contact with the stomach may be covered. When one end of the stent is deployed near the ampulla of Vater and the duodenum and the other end is deployed in the bile duct, the end on the bile duct side may be covered. In some embodiments, any of the stents disclosed herein may include a cover on both ends of the stent. In some embodiments, the central portion or the portion between the upstream flange and the downstream flange may be uncovered. The uncovered central portion may be used for fluid drainage from the pancreatic duct when both ends of the stent are located in the duodenum and the bile duct.

[0034] In some embodiments, the cylindrical saddle region 206 of the stent 200 is covered to prevent fluid leakage to the outside of the cylindrical saddle region 206. The stents disclosed herein can be deployed in the body as described herein, such that the cylindrical saddle region 206 forms a fluid conduit between body tubular lumens within the peritoneum. The covered cylindrical saddle region 206 can prevent leakage into the peritoneum. Leakage of biomaterial into the peritoneum can cause serious complications. As a result, the stent may have a covering to prevent fluid or material from leaking to the outside of the cylindrical saddle region 206 of the stent 200. The covering may also be used on the ends of the stent configured to connect to the stomach or duodenum.

[0035] Examples of manufacturing techniques that may be used to produce the stents disclosed herein include the use of laser cutting, braiding, welding, etching, and wire forming. A membrane material such as silicone can be applied to the wire stent frame to prevent the passage of fluid through the stent wall. The membrane or coating material can be applied by painting, brushing, spray coating, dipping, or forming.

[0036] Furthermore, in some embodiments, the stent 200 can be formed by braiding wire (or multiple wires) on a mandrel and then crimping a sleeve over the mandrel to form the stent 200. In particular, the mandrel can have an inverted shape of the channel 208 engraved on the mandrel, and a sleeve that fits the protruding channel 208 structure and is compatible with the mandrel can form the channel 208 on the body 202 of the stent 200. Furthermore, the formed stent can be annealed using an annealing process.

[0037] Figure 3 shows a stent 300 according to several embodiments of the present disclosure. The stent 300 may have a body 302, a flange 304, a cylindrical saddle region 306, and a channel 308, similar to the stent 200 in Figures 2A and 2B. However, the stent 300 may have a flange 304 at one end and a flare 310 at the opposite end. Generally, the flare 310 is configured to prevent or restrict the downstream movement of the stent 300.

[0038] Figures 4A and 4B show stents 400a and 400b according to some embodiments of the present disclosure, respectively. The stents 400a and 400b shown in these figures have a body 402, a flange 404, a cylindrical saddle region 406, and channels 408a and 408b. However, the helical channels 408a and 408b are not symmetrical. For example, Figure 4A shows a stent 400a having a channel 408a. The channel 408a is wider at the upstream end of the stent 400a and narrows as the channel 408a extends (or spirals) along the longitudinal direction of the stent 400a.

[0039] Similarly, Figure 4B shows a stent 400b with channel 408b, which narrows at the upstream end of stent 400b. Channel 408b widens as it extends along the longitudinal direction of stent 400b (or spirals around it). In some applications, repeated inflows into a spiral channel can create a fluid path along the length of the stent, potentially causing backflow or channel blockage due to the total fluid volume exceeding the channel's capacity. However, the asymmetric channels shown in these figures can overcome this limitation. Similarly, a channel with a wider inlet (e.g., channel 408a) offers more opportunities to align with side branches and can act as a funnel to guide fluid into the spiral channel. A wider inlet can also act as a reservoir, applying a downstream force to the fluid volume and facilitating continuous flow through the channel.

[0040] Figures 5A and 5B show stents 500a and 500b, respectively, according to some embodiments of the present disclosure. The stents 500a and 500b shown in these figures comprise a body 502, a flange 504, a cylindrical saddle region 506, and channels 508 having different pitches 510a, 510b. More specifically, the helical channels 508 have different spacing or distances between consecutive channels 508. For example, Figure 5A shows stent 500a with channels 508 having a pitch 510a. This pitch 510a is wider than the pitch 510b of the channels 508 in stent 500b shown in Figure 5B. In some examples, stents 500a and 500b can be intended for deployment to different locations based on the density (or pitch) of the channels 508.

[0041] Figures 6A and 6B show stents 600a and 600b, respectively, according to some embodiments of the present disclosure. Generally, stents 600a and 600b can be similar to the Axios® stents offered by Boston Scientific® and can be configured to be deliverable via a Hot Axios® device. For example, stents 600a and 600b may have a body 602, a flange 604, and a cylindrical saddle region 606. Notably, however, stents 600a and 600b have a curved region 608 within the cylindrical saddle region 606. The curved region 608 can bend along the longitudinal direction of the stent.

[0042] In some embodiments, stents 600a and 600b can be used to manage symptomatic cholecystitis in patients at high risk for surgery or who are unsuitable for surgery. It should be noted that early laparoscopic cholecystectomy is the treatment option for acute cholecystitis in most cases. However, in elderly patients, critically ill patients, and patients with significant comorbidities, cholecystectomy is considered a high-risk procedure, and gallbladder drainage (GBD) is recommended as an alternative treatment.

[0043] To date, percutaneous transhepatic gallbladder drainage (PTGBD) is the most commonly used gallbladder drainage (GBD) procedure in clinical practice. Although the technical success rate of PTGBD is high at 98.9%, the clinical success rate is low at 86.0%, with adverse events such as intrahepatic hemorrhage, pneumothorax, biliary peritonitis, and pneumonia contributing to the 4.0% procedure-related mortality rate. With readmission rates up to 42% and recurrence rates ranging from 4.1% to 22%, there is a need for additional treatment options to complement existing management strategies.

[0044] The stents 600a and 600b, when deployed via a system such as the Hot Axios® system, may be an option for high-risk or surgically unsuitable patients. Published literature demonstrates the clinical and technical success of creating a new, temporary opening between the gallbladder and the gastrointestinal tract (e.g., the duodenum) for symptomatic cholecystitis in high-risk or surgically unsuitable patients. EUS-GBD using Hot Axios®, when performed by an experienced endoscopist, is an option for high-risk surgical patients with acute cholecystitis.

[0045] However, impaction of food from the duodenal side can obstruct drainage, and there is a potential risk of infection due to the trapping of contents within an already diseased gallbladder. The curved region 608 can be positioned to utilize natural anatomical pressure-driven and gravity-based drainage to enable drainage from the gallbladder while providing a more resistant pathway to reflux drainage and impaction from the duodenal region. This is shown more clearly in Figure 7. For example, extending the bridge distance (i.e., the length of the cylindrical saddle region 606) can achieve a similar position, resulting in even greater resistance to reflux drainage.

[0046] In some embodiments, the stent 600a and / or 600b may include multiple curved regions 608 to further increase resistance to reflux into the gallbladder, for example. In addition, in some embodiments, the curved regions 608 may be formed across multiple planes on the device. This may provide better placement options and potential relocation of blood vessels (which would reduce tension on the device and decrease the possibility of movement) and / or reduce reflux pressure.

[0047] In some examples, the stents 600a and / or 600b may have a tapered body combined with a curved region 608 so as to provide a wide inlet side for drainage and a narrower outlet side to prevent backflow pressure.

[0048] In some embodiments, stents 600a and 600b can be manufactured using a curved mandrel and clamp sleeve. In some embodiments, stents such as the Axios® stent can be used in EUS-guided hepatogastric anastomosis (HGS) procedures. Figures 8A, 8B, 8C, and 8D show stents 800a, 800b, 800c, and 800d, respectively. Stents 800a–800d have a body 802, a distal flange 804, and a straight or tapered proximal end 808a, the proximal end 808a having a cylindrical saddle region 806 between it and the flange 804. The distal end with the flange 804 can be positioned to be inserted downstream, i.e., toward the patient's stomach, while the proximal end 808a can be positioned upstream, i.e., toward the patient's liver. The proximal end 808a may have a loop-shaped end to assist in retrieval. Furthermore, in some embodiments, the stents 800a-800d may be bare (e.g., uncovered) or partially covered with a covering 810 as shown. In some embodiments, the covering 810 allows the stents 800a-800d to be used as a bridge between the gastrohepatic drainage space, preventing leakage into the abdominal cavity while allowing tissue intrusion for drainage and migration prevention by the uncovered end placed in the hepatic space.

[0049] Stents 800a–800d further include anti-migration fins (e.g., anti-migration fin 812a or anti-migration fin 812b). Generally, the anti-migration fins may be loops provided at the uncovered end of the stent (e.g., the proximal end) projecting from the longitudinal plane of the stent. The anti-migration fins may be oriented to face the liver, the distal, or a combination of both directions, as shown herein. The anti-migration fins reinforce the uncovered area of ​​the stent in the liver and provide a more abrupt anti-migration mechanism against the uncovered surface. The uncovered surface alone often requires a certain amount of time (usually several days to several weeks, depending on the anatomical structure of the liver) to form a chronic anti-migration mechanism.

[0050] For example, Figure 8A shows a stent 800a according to some embodiments of the present disclosure. The stent 800a has a linear proximal end 808a and an anti-movement fin 812a facing downstream (e.g., away from the hepatic duct).

[0051] For example, Figure 8B shows a stent 800b according to some embodiments of the present disclosure. The stent 800b has a tapered proximal end 808b and its anti-movement fins 812a are oriented downstream (e.g., away from the hepatic duct) as in the stent 800a.

[0052] For example, Figure 8C shows a stent 800c according to some embodiments of the present disclosure. The stent 800c has a linear proximal end 808a and an anti-movement fin 812a facing both upstream and downstream.

[0053] For example, Figure 8D shows a stent 800d according to some embodiments of the present disclosure. The stent 800d has a tapered proximal end 808b and an anti-movement fin 812a facing both upstream and downstream.

[0054] As described above, this disclosure provides an embodiment of a stent usable in endoscopic retrograde cholangiopancreatography (ERCP) procedures. The ERCP procedure may include the step of advancing an endoscope into the intestine through the mouth and stomach. The endoscope may advance to a region of the intestine adjacent to the ampulla of Vater. A guidewire may be advanced from the working channel of the endoscope to the ampulla of Vater and into the common bile duct or pancreatic duct. A catheter equipped with a self-expanding stent advances over the guidewire and is able to access the common bile duct or pancreatic duct. The catheter may retract its sheath to allow the self-expanding stent to expand. The sheath is partially retractable so that the first end, i.e., the upstream end, of the stent is expandable in the common bile duct or pancreatic duct. After the upstream end is deployed, the sheath is further retractable so that the second end, i.e., the downstream end, of the stent is deployable. The downstream end of the stent is deployable to the ampulla of Vater, the intestine, or other region of the common bile duct or pancreatic duct. The cylindrical saddle region of the stent forms a fluid conduit or pathway between the common bile duct or pancreatic duct and the ampulla of Vater or the intestine, or to other regions of the common bile duct or pancreatic duct.

[0055] Figures 9A and 9B show examples of body lumens connectable by the stents disclosed herein. In each region of the abdominal cavity, the stents described herein can be used to “span” or “connect” the common bile duct to the duodenum, or the stomach to various locations within the biliary system. In other words, Figures 9A and 9B show the various sites in the abdominal cavity where stents can be placed. In some embodiments, any stent disclosed herein can be placed in any site shown in these figures. For example, any procedure shown in Figure 9A or Figure 9B can be used as an alternative to the ERCP procedure. In some cases, the ERCP procedure may be unsuccessful or impossible to perform. In such cases, it is possible to place a stent through any of the routes shown in Figures 9A and 9B.

[0056] More specifically, looking at Figure 9A, various parts of the abdominal cavity 902 of patient 904 are shown. For example, the stomach 906, duodenum 908, pancreas 910, liver 912, common bile duct 914, hepatic duct 916, gallbladder 918, and cystic duct 920 are shown. Furthermore, various stent placement routes are shown.

[0057] For example, Figures 9A and 9B show a choledochodudenostomy 922 connecting the common bile duct 914 to the duodenum 908. For the choledochodudenostomy, an endoscope can be advanced into the duodenum 908 through the mouth and stomach 906. The target site within the common bile duct 914 can be identified using ultrasound guidance or other guidance methods. A needle or catheter device can be advanced from the endoscope to puncture the walls of the duodenum 908 and the common bile duct 914. When accessing the common bile duct 914 using a needle, a guidewire can be positioned, and the catheter can be advanced over the guidewire to access the common bile duct 914. The catheter can be deployed with its upstream end or flange positioned in the common bile duct 914 and its downstream end or flange positioned in the duodenum 908 to form a stent, thereby creating a fluid conduit between the common bile duct 914 and the duodenum 908.

[0058] As another example, Figures 9A and 9B show a hepatogastrostomy 924 connecting the hepatobiliary duct 920 to the stomach 906. To perform the hepatogastrostomy 924, an endoscope can be inserted through the mouth and advanced into the stomach 906. The target site in the liver 912 can be identified using ultrasound guidance or other guidance methods. A needle or catheter device can be advanced to puncture the stomach 906 and the liver 912. (After access with the needle,) a guidewire can be placed in the liver 912, and then a catheter with a stent can be placed over the guidewire and advanced. Using the catheter, the upstream end of the stent can be placed in the liver 912 and the hepatic duct 916. The downstream end of the stent is deployed in the stomach 906. The stent may have an uncovered portion at the end of the stent that is deployed in the liver 912 and the hepatic duct 916. For example, the upstream end deployed in the liver 912 may have an uncovered portion of about 3-4 cm. The uncovered portion at the end of the stent facilitates the flow of bile from the liver and its drainage through the stent's internal space into the stomach 906. The pressure within the liver 912 assists the drainage of bile from the liver 912 through the stent to the stomach 906. The downstream end of the stent deployed within the stomach 906 may be covered to reduce contact between the bile and the wall of the stomach 906.

[0059] In another example, Figures 9A and 9B show a pancreaticogastrostomy 926, in which an endoscope is inserted through the mouth and can be advanced into the stomach 906. The target site (e.g., tubule) within the pancreas 910 can be identified using ultrasound guidance or other guidance techniques. A needle or catheter device can be advanced from the endoscope to puncture the wall of the stomach 906 and the tubule within the pancreas 910. (After access with the needle,) a guidewire can be placed within the pancreas 910, and then a catheter with a stent can be placed over the guidewire and advanced. Using the catheter, the upstream end of the stent can be placed in the tubule within the pancreas 910. The downstream end of the stent is deployed into the stomach 906, thereby creating a fluid conduit between the tubule within the pancreas 910 and the stomach 906.

[0060] In some embodiments, the stents disclosed herein can be used for antegrade stent placement. Antegrade stent placement is possible within the ducts of the common bile duct 914 and the pancreas 910. Antegrade stent placement refers to a procedure in which the operator accesses the upstream portion of the common bile duct 914 (or the duct within the pancreas 910). The upstream portion of the common bile duct 914 can be accessed percutaneously (e.g., transhepatically) or under EDS guidance (e.g., transgastrointestinal targeting of the intrahepatic or extrahepatic bile duct). After securing access to the upstream portion of the bile duct, a guidewire is inserted and advanced downstream, passing through the stenosis and the ampulla of Vater, into the duodenum 908. The stent then advances antegrade over the wire, passing through the stenosis and the ampulla of Vater, until the downstream end of the stent is positioned within the duodenum 908. The sheath is retracted relative to the stent, releasing the downstream flange or double-wall flange. The sheath and stent can then be retracted together until the flange contacts the ampulla of Vater. This contact is confirmed by the resistance generated during retraction. The sheath then retracts relative to the stent, and the upstream flange is deployed into the common bile duct 914. A similar procedure can be used to secure access to the upstream portion of the pancreas 910 and then antegrade the stent into the duct within the pancreas 910.

[0061] It should be noted that the matters described above do not constitute a complete description of exemplary procedures in which the stents described herein may be used. Rather, the above are provided merely as examples and should not be construed as limiting the scope of the disclosure herein. The scope of this disclosure is defined by the appended claims and the claims of any subsequent applications that take priority from this application.

Claims

1. It is a stent, The device comprises a main body, the main body comprising an elongated tubular configuration and a shortened configuration, the elongated tubular configuration having an upstream end that expands into an upstream structure and a downstream end that expands into a flange structure, the main body comprising a cylindrical saddle region provided between the upstream structure and the flange structure, the main body comprising a channel extending spirally around its outer circumference, the channel defined on the outside of the main body and reflected on the inside of the main body, A stent in which the width of the channel is wider at the upstream end of the main body than at the downstream end of the main body, or the width of the channel is wider at the downstream end of the main body than at the upstream end of the main body.

2. The stent according to claim 1, wherein the channel has a constant pitch along the longitudinal direction of the main body.

3. The stent according to claim 1, wherein the pitch of the channel increases along the longitudinal direction of the body.

4. The stent according to claim 3, wherein the pitch increases along the longitudinal direction of the main body from the upstream end to the downstream end.

5. The stent according to any one of claims 1 to 4, wherein the upstream structure comprises a flange or a flare.

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