Devices and methods for attaching unconnected anatomical structures

Abstract

An exemplary stent may include a tubular member formed by at least one braided filament with battens forming a plurality of twisted knit stitches, the battens extending circumferentially between radially adjacent twisted knit stitches, each twisted knit stitch interconnected with a longitudinally adjacent twisted knit stitch forming a series of connected knit stitches. The tubular member may be implanted to move between a relaxed configuration and an extended configuration to connect two spaced apart anatomical locations within the digestive tract. The tubular member has a first longitudinal length in the relaxed configuration and a second longitudinal length in the extended configuration, the first longitudinal length being less than the second longitudinal length.

Description

Technical Field

[0001] The present disclosure relates to medical devices, methods for manufacturing medical devices, and their use. More specifically, the present disclosure relates to stents for implantation within a body lumen and related methods.

Background Art

[0002] Implantable medical devices (e.g., expandable stents) can be designed to treat various medical conditions within the body. For example, some expandable stents can be designed to expand radially, support a body lumen, and / or provide a fluid pathway for digested material, blood, or other bodily fluids to flow after a medical procedure. Some medical devices can include radially expandable or self-expandable stents that can be implanted percutaneously by various medical device delivery systems. These stents can be implanted within various body lumens such as the coronary or peripheral arteries, esophagus, gastrointestinal tract (including the intestine, stomach, and colon), bronchi, urinary tract, biliary tract, vascular system, etc.

[0003] In some instances, it may be desirable to design a stent to include sufficient flexibility while maintaining a radially directed force sufficient to open the body lumen at the treatment site. However, in some stents, due to the compressibility and flexibility characteristics that assist in stent delivery, the stent has a tendency to move from its initially implanted position. For example, stents designed to be placed in the gastrointestinal tract and biliary tract can tend to move due to peristaltic motion (i.e., involuntary contractions and relaxations of the muscles of the stomach, intestine, and colon). Additionally, the generally moist and inherently slippery environment of the stomach, intestine, colon, etc. further promotes the tendency of the stent to move when placed therein.

[0004] Various medical procedures involve the temporary or permanent joining of unconnected anatomical structures. Some examples include hepaticogastrostomy (HGS), which involves joining the stomach to the hepatic duct for drainage; gastrojejunal (GJ) bypass surgery to form an anastomosis between the small intestine wall and the stomach wall; and stoma surgery to create an artificial opening in the large intestine or other areas of the digestive tract. In these medical procedures, peristaltic movement and macroscopic organ movement in one or both of the connected anatomical structures can make it difficult to use a stent to join the structures, due to stent migration.

[0005] Therefore, it may be desirable to design stents with anti-migration mechanisms to reduce the tendency for stents to move. Examples of medical devices including anti-migration mechanisms and methods of using them are disclosed herein. [Overview of the Initiative]

[0006] This disclosure provides alternative designs, materials, manufacturing methods, and uses for medical devices. An exemplary stent configured to connect two spaced anatomical locations comprises an elongated tubular member having a longitudinal axis, the elongated tubular member comprising at least one knitted filament comprising rungs that form a plurality of twisted knit stitches, the rungs extending circumferentially between radially adjacent twisted knit stitches, each twisted knit stitch interconnected with longitudinally adjacent twisted knit stitches that form a series of connected stitches, the elongated tubular member configured to move between a relaxed state and an extended state, each of the plurality of twisted knit stitches being formed by a single filament that forms a loop portion and an intersecting base region, the elongated tubular member having a first longitudinal length in the relaxed state and a second longitudinal length in the extended state, the first longitudinal length being shorter than the second longitudinal length.

[0007] Alternatively or additionally to the above embodiments, the elongated tubular member has a first outer diameter in a relaxed state and a second outer diameter in an extended state, wherein the first and second outer diameters are substantially the same.

[0008] Alternatively or in addition to any one of the embodiments described above, the first and second outer diameters are defined by the struts. Alternatively or in addition to any one of the embodiments described above, at least some loop portions of the twisted stitch are wrapped around the intersecting base region of longitudinally adjacent twisted stitches.

[0009] In addition to or alternative to any one of the embodiments described above, when in a relaxed state, the struts form the outer surface of an elongated tubular member, and the base region where each twisted stitch intersects extends radially outward from the outer surface.

[0010] Alternatively or additionally to any one of the embodiments described above, the intersecting base regions form raised ridges that spirally extend around the elongated tubular member in the relaxed form.

[0011] In addition to or alternative to any one of the above embodiments, at least one braided filament is a single braided filament. An exemplary method for providing an artificial bridge between a patient's first organ and a second organ includes the steps of fixing the first end of an expandable stent to the first organ and the second end of the stent to the second organ so that the interior of the first organ is in fluid communication with the interior of the second organ through the stent, the first organ and the second organ being spaced apart, at least one of the first organ and the second organ moving relative to the other of the first organ and the second organ during the normal functioning of the first organ and the second organ, and the stent comprising an elongated tubular member having a longitudinal axis, the elongated tubular member comprising at least one braided braided stitch having ribs to form a plurality of twisted braided stitches The tubular member is configured to move between a relaxed state and an extended state, with each of the twisted stitches being interconnected with longitudinally adjacent twisted stitches forming a series of connected stitches. Each of the twisted stitches is formed by a single filament forming a loop portion and an intersecting base region. The tubular member has a first longitudinal length in the relaxed state and a second longitudinal length in the extended state, the first longitudinal length being shorter than the second longitudinal length.

[0012] Alternatively or additionally to the above embodiment, the first organ is the hepatic duct, and the second organ is the patient's stomach. Alternatively or in addition to any one of the embodiments described above, the stent comprises an uncoated portion and a coated portion, the coated portion comprising at least 70% of the length of the stent, the coated portion comprising a fluid-impermeable coating, and the uncoated portion extending into the hepatic duct.

[0013] Alternatively or in addition to any one of the embodiments described above, the first organ is the patient's stomach, and the second organ is a portion of the patient's small intestine. Alternatively or in addition to any one of the embodiments described above, the first organ is the patient's skin, and the second organ is a portion of the patient's large intestine.

[0014] Alternatively or in addition to any one of the embodiments described above, the first end of the stent includes a flange positioned on the outer surface of the skin. Alternatively or in addition to any one of the embodiments described above, the second end of the stent is positioned coaxially within the large intestine.

[0015] Alternatively or in addition to any one of the embodiments described above, the second end of a stent coaxially positioned in the colon includes an outward-facing flared region. In an alternative or additional configuration to any of the embodiments described above, the patient's stomach comprises a gastric pouch portion separated from the excluded gastric portion and a Roux limb connecting the gastric pouch portion to the patient's small intestine, wherein the first organ is the gastric pouch portion and the second organ is the excluded gastric portion.

[0016] Alternatively or in addition to any one of the embodiments described above, after the stent has been fixed, the method further includes inserting an endoscope into the gastric pouch portion, inserting it through the stent into the gastric portion excluded from the stent, inserting it into the patient's duodenum, and then performing endoscopic retrograde cholangiopancreatography (ERCP).

[0017] Alternatively or in addition to any one of the embodiments described above, the method further includes the step of removing the stent after the ERCP is completed. Another exemplary method for draining fluid from a first organ to a second organ in a patient's gastrointestinal tract is the step of inserting an implantable stent into the patient's body, the stent comprising a tubular member formed from at least one braided wire filament, the tubular member comprising ribs forming a plurality of twisted braided stitches, the ribs extending circumferentially between circumferentially adjacent twisted braided stitches, each twisted braided stitch comprising a loop portion and an intersecting base region, and corresponding to longitudinally adjacent twisted braided stitches forming a series of connected stitches. The procedure includes the steps of inserting a stent, wherein the tubular members are interconnected and configured to move between a relaxed form having a first longitudinal length and a first diameter and an extended form having a second longitudinal length and a second diameter, the first longitudinal length being shorter than the second longitudinal length, and the first and second diameters being substantially the same; and positioning the first end of the tubular member in a first organ of the patient and the second end of the tubular member in a second organ of the patient, the first and second organs being spaced apart from each other and moving relative to each other during digestion.

[0018] Alternatively or additionally to the above embodiments, when in a relaxed state, the struts form the outer surface of the tubular member, and the intersecting base region of each twisted knitted stitch extends radially outward from the outer surface.

[0019] The above-described summary relating to some embodiments is not intended to describe each or all embodiments of the disclosed invention. The following drawings and detailed description illustrate these embodiments more specifically. [Brief explanation of the drawing]

[0020] The present invention can be better understood by considering the following detailed description of various embodiments in relation to the accompanying drawings. [Figure 1] This is a diagram showing a part of the digestive tract. [Figure 2A] This diagram shows the movement of the stomach relative to the hepatic duct. [Figure 2B]It is a diagram showing the movement of the stomach relative to the bile duct. [Figure 3A] It is a diagram showing a braided stent of the prior art. [Figure 3B] It is a diagram showing a braided stent of the prior art. [Figure 4] It shows a part of the pattern of a stent braided in parallel in the prior art. [Figure 5] It is a perspective view of an exemplary stent in a relaxed configuration. [Figure 6] It is an enlarged top view of a part of the exemplary stent of FIG. 5. [Figure 7] It is a diagram of the stent of FIG. 5 in an extended configuration within a delivery sheath. [Figure 8] It is an enlarged partial view of the stent of FIG. 7. [Figure 9] It is an enlarged side view of the longitudinal edge of the exemplary stent of FIG. 5. [Figure 10] It is a partial view of the stent of FIG. 5 disposed within a body organ. [Figure 11A] It is a diagram of a braided stent of the prior art in a relaxed configuration. [Figure 11B] It is a diagram of the stent of FIG. 11A in an extended configuration. [Figure 12A] It is a diagram of the stent of FIG. 5 in a relaxed configuration. [Figure 12B] It is a diagram of the stent of FIG. 12A in an extended configuration. [Figure 13] It is a diagram of another exemplary stent having a flare end. [Figure 14] It is a diagram showing an exemplary stent connecting the bile duct and the stomach. [Figure 15] It is a diagram showing an exemplary stent connecting the stomach and the small intestine. [Figure 16] It is a diagram showing an exemplary stent connecting the large intestine to the skin surface. [Figure 17]This figure shows an exemplary stent connecting to the gastric portion of the stomach, with the gastric pouch excluded, as the endoscope extends through the stent during a subsequent endoscopic retrograde cholangiopancreatography (ERCP) procedure. [Modes for carrying out the invention]

[0021] While various modifications and alternative forms of the present invention are possible, their details are shown in the drawings as examples and will be described in detail. However, it should be understood that the intent is not to limit the aspects of the present invention to the specific embodiments described. Rather, the intent is to cover all modifications, equivalents, and alternatives that fall within the scope of the present invention.

[0022] The following defined terms shall apply unless otherwise given in the claims or elsewhere herein. In this specification, all numerical values ​​are assumed to be qualified with the term “approximately,” whether explicitly stated or not. The term “approximately” generally refers to a range of numerical values ​​that a person skilled in the art would consider equivalent to (i.e., having the same function or result as) the listed values. Often, the term “approximately” may indicate that the numerical values ​​are rounded to the nearest significant figure.

[0023] Listing numerical ranges by endpoints includes all numbers within that range (for example, 1-5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5). While appropriate dimensions, ranges, and / or values ​​relating to various components, features, and / or specifications are disclosed, those skilled in the art, stimulated by the present invention, will understand that it is possible to deviate from the desired dimensions, ranges, and / or values ​​that are expressly disclosed.

[0024] As used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural subjects unless the context clearly indicates otherwise. As used herein and in the appended claims, the term “or” is used generally in its sense to include “and / or” unless the context clearly indicates otherwise.

[0025] The following detailed description should be read in reference to the drawings, which use the same reference numerals for similar elements across different drawings. The detailed description and drawings are not necessarily to scale and illustrate exemplary embodiments, and are not intended to limit the scope of the invention. The exemplary embodiments shown are intended for illustrative purposes only. Selected features of any exemplary embodiment may be incorporated into additional embodiments unless otherwise explicitly stated.

[0026] Figure 1 illustrates the various organs within the digestive tract, including the stomach 150, duodenum 154, liver 160, hepatic duct 162, gallbladder 166, common bile duct 164, and pancreas 168. Bile produced in the liver 160 flows through a series of hepatic ducts 162 and is discharged into a single large tube called the common bile duct (CBD) 164. The CBD then connects to the duodenum 154, where the bile can flow into the duodenum for digestion. If the liver or bile duct is obstructed, bile is not discharged normally and may reflux into or accumulate in the liver. Bile duct obstruction can cause jaundice, dark urine, nausea, and loss of appetite and can potentially lead to serious conditions.

[0027] Endoscopic retrograde cholangiopancreatography (ERCP) can be used to diagnose and treat conditions of the bile ducts, including, for example, gallstones, inflammatory strictures, leakage (e.g., due to trauma, surgery, etc.), and cancer. Bile duct obstruction can occur in many disorders of the biliary system, including primary sclerosing cholangitis, stone formation, and liver damage such as scarring within the bile duct. Draining the obstructed fluid in the biliary system can be performed to treat the disorder. Biliary drainage methods include the placement of plastic or metal stents to alleviate the obstruction. In the case of gallstones causing obstruction within the duct, numerous products are also available to resolve this by ERCP. However, access to the bile ducts by ERCP may be impossible for various reasons, such as tumors blocking the passage, anatomical variations, or peripapillary diverticulum.

[0028] If ERCP is unsuccessful, percutaneous drainage (PTCD) can be performed. However, PTCD can be associated with complications such as bleeding and bile leakage. If internal drainage cannot be achieved afterward, the patient must accept long-term external biliary drainage, which can be uncomfortable and significantly impair their quality of life.

[0029] Endoscopic ultrasound-guided biliary drainage (BD) offers an alternative to surgery and percutaneous drainage for treating obstructive jaundice when ERCP drainage fails. Hepatogastric anastomosis (HGS) may be performed to connect the hepatic duct 162 to the stomach 150. This allows bile accumulation to flow into the stomach and can alleviate symptoms caused by bile accumulation, namely jaundice. However, the hepatic duct 162 and the stomach 150 are separated by a distance 5, indicated by the arrow in Figure 1. The distance 5 between the organs requires a relatively long stent. In addition, as the gastric muscle contracts to agitate food, the distance 5 between the gastric wall 153 of the stomach 150 and the hepatic duct 162 changes from a relatively small distance 5 when the stomach is relaxed, as shown in Figure 2A, to a larger distance 5 when the stomach is contracted, as shown in Figure 2B. In addition to the curvature of the stomach wall, the stomach undergoes peristalsis during digestion. This relative movement of the stomach is understood to be complex not only linearly but also three-dimensionally. The distance between the target organs to be joined, and the relative movement of at least one of the organs, can increase the opportunity for the stent to move.

[0030] Conventional braided stents 170 and 180, as shown in Figures 3A and 3B, may be used in HGS. The braided stents 170, 180 may be self-expanding metallic stents having proximal flanges 172, 182 and may typically have a coating 174, 184 extending 70% of the stent's length. The coated portion or length region 176, 186 is configured to span the peritoneal cavity between the stomach and the hepatic duct, preventing bile leakage into the peritoneum and forming a sealed channel between the two organs. The 30% uncoated distal portion of the stents 170, 180 may be configured to allow initial acute side-branch flow of bile into the stent and, in post-acute situations, to allow internal tissue growth into the stent to reduce migration. However, migration may still occur, possibly due to the movement of the stomach relative to the hepatic duct.

[0031] For HGS patients, stent migration can lead to serious complications, including death. If there is no adhesion due to internal tissue growth in the hepatic duct, the stent may migrate proximally into the stomach, causing leakage of bile duct contents into the peritoneum and leading to peritonitis. If there is sufficient or excessive adhesion in the hepatic duct, the stent may migrate distally into the peritoneum, causing leakage of bile and stomach contents into the peritoneum, which can also lead to peritonitis. In addition, a migrated stent may rub against the outer stomach wall and other nearby organs or blood vessels without restriction.

[0032] Anatomically, stent migration can occur as a result of the gastric duct 150 being a highly mobile vessel compared to the hepatic duct 162, which is generally a static vessel, as shown in Figure 2. This movement can cause stent migration when the stomach wall slides / pushes over the proximal flange of the stent during gastric contraction. Braided stents may be more prone to migration because their diameter decreases (contracts) when longitudinal forces are applied. This phenomenon is particularly noticeable during stent removal procedures. In addition, depending on the design of the braided stent, much greater force may be required to reduce (contract) the diameter of the knit, resulting in a fixed-length device that is more prone to migration and can have similar problems because it is delivered by a less helpful crochet delivery system.

[0033] Figure 4 shows a portion of a conventional self-expanding braided stent 90. Conventional braided self-expanding stents are generally designed using an automated transverse braiding process, which generates parallel rows 92 of braided stitches extending parallel to the longitudinal axis of the stent in both the expanded relaxed and stretched contracted forms. The parallel braided stent 90 provides good radial strength with minimal shortening. However, this parallel braided stent design can be difficult to contract, particularly in coaxial delivery systems, and may therefore be delivered using systems that do not offer a method of recapture, such as crochet delivery systems. Furthermore, the parallel braided stent design tends to migrate in its original location. There is a need for an alternative braided self-expanding stent that has similar fit and radial strength to previous parallel braided stent configurations, but is resistant to migration and can adapt its length without a significant reduction in lumen diameter, leaving the drainage channel intact.

[0034] Figure 5 shows a perspective view of an exemplary implant, which is a stent 10, etc., for forming an artificial bridge to connect adjacent organs, but is not limited to. In some examples, the stent 10 may be an expandable stent formed as an elongated tubular member 12 with a helical design. Although the stent 10 is described as substantially tubular, it is assumed that the stent 10 can take any desired cross-sectional shape. The stent 10 may have a first end (i.e., proximal end) 14, a second end (i.e., distal end) 16, and an intermediate region 18 located between the proximal end 14 and the distal end 16. The stent 10 may include a lumen 20, which extends from a first opening adjacent to the proximal end 14 to a second opening adjacent to the distal end 16, allowing the passage of fluids, etc.

[0035] The stent 10 may be made from at least one filament 24 that forms open cells 25 and twisted stitches 22. In some embodiments, the stent 10 may be made from only a single filament 24 that is woven together with itself to form the open cells 25 and twisted stitches 22. In some cases, the filament 24 may be a monofilament, while in other cases, the filament 24 may be two or more filaments that are wound, braided, or woven together. In some embodiments, the inner surface of the stent 10 may be covered entirely, substantially, or partially with a fluid-impermeable covering or coating 21. In other embodiments, the coating 21 may be provided on the outer surface of the stent. In some embodiments, the covering may be a polymer. The covering or coating may extend across and / or occlude one or more open cells 25 and twisted stitches 22 formed by the filament 24. The covering or coating may prevent leakage of bile into the peritoneum.

[0036] Stent 10 is expected to be made from many different materials, including but not limited to metals, metal alloys, shape memory alloys, and / or polymers, which, if desired, can expand to conform to the shape when precisely positioned within the body. In some examples, the material may be selected so that stent 10 can be removed relatively easily. For example, stent 10 can be formed from alloys, including but not limited to Nitinol and Elgiloy®. Depending on the material selected for construction, stent 10 may be self-expanding (i.e., configured to automatically expand radially when not contracted). In some embodiments, stent 10 may be made using fibers. The fiber may be, for example, a composite fiber having an outer shell made of Nitinol with a platinum core. It is further expected that stent 10 may be formed from polymers, including but not limited to polyethylene terephthalate (PET). Stent 10 may be self-expanding. As used herein, the term “self-expanding” refers to the tendency of a stent to return to a pre-programmed diameter when released from an external biasing force (e.g., a delivery catheter or sheath, but not limited to these). In some examples, in a relaxed expansion configuration as shown in Figure 5, the stent 10 may include a first end region 23 adjacent to the proximal end 14 and a second end region 28 adjacent to the distal end 16.

[0037] In some embodiments, the stent 10 may have a uniform outer diameter from the proximal end 14 to the distal end 16 when in a relaxed, expanded state, as shown in Figure 5. In some embodiments, the outer diameter of the intermediate region 18 may range from 15 to 25 millimeters. The outer diameter of the anti-movement flares (proximal end 14 and / or distal end 16) may range from 20 to 30 millimeters. It is assumed that the outer diameter of the stent 10 can be modified to suit the desired application.

[0038] The stent 10 is expected to be made from many different materials, including but not limited to metals, metal alloys, shape memory alloys, and / or polymers, which can expand to conform to the shape of the body when precisely positioned within the body, as desired. In some examples, the material may be selected so that the stent 10 can be removed relatively easily. For example, the stent 10 can be formed from alloys, including but not limited to Nitinol and Elgiloy®. Depending on the material selected for construction, the stent 10 may self-expand or require external force to expand. In some embodiments, a composite filament may be used to fabricate the stent 10. The composite filament may include, for example, an outer shell or cladding made of Nitinol and a core formed of platinum or other radiopaque material. It is further expected that the stent 10 may be formed from polymers, including but not limited to polyethylene terephthalate (PET). In some cases, the filaments or parts thereof of the stent 10 may be bioabsorbable or biodegradable, while in other cases, the filaments or parts thereof of the stent 10 may be biostable.

[0039] Figure 6 shows details of the helical structure of the stent 10 when it is in a relaxed, expanded state. The stent 10 as shown may be manufactured from a single filament 24. The single filament 24 forms a twisted braided stitch 22, which is separated from adjacent twisted braided stitches 22 in the circumferential direction by elongated ribs 26 that extend circumferentially between them. As shown in Figure 6, each twisted braided stitch 22 may be interconnected with longitudinally adjacent twisted braided stitches 22 to form a series of connected stitches that extend helically around the stent in a relaxed, expanded state. The interconnected twisted braided stitches 22 may extend helically around the stent 10 along its entire length. In some embodiments, when the stent 10 is in a fully relaxed state, the ribs 26 may extend substantially perpendicular to the longitudinal axis xx of the stent 10, as shown in Figure 6. In some embodiments, the strut 26 may have a length between 0.1 mm and 10.0 mm in its relaxed, extended form. In other examples, the strut may have a length between 1 mm and 5 mm. In yet another example, the strut 26 may have a length between 2 mm and 3 mm.

[0040] Figure 7 shows the stent 10 in an extended and compressed state placed within the delivery sheath 13. As the stent 10 is folded and extended when inserted into the delivery sheath 13, as shown in Figure 7, the spirally interconnected twisted stitches 22 straighten out into longitudinal rows. The twisted stitches 22 are extended, and the ribs 26 are shortened. The structure of the twisted stitches 22 in the extended, compressed, and contracted states is shown in Figure 8. Each twisted stitch 22 may include a loop portion 30 and an intersecting base region 32. The loop portion 30 may wrap around the intersecting base region 32 of a longitudinally adjacent twisted stitch 22. The intersecting base region 32 is distal to the loop portion 30 at the distal end 16 of the stent, as shown in Figure 8, so that the intersecting base region 32 forms a non-traumatic structure. The loop portion 30 has an elongated or elliptical shape in the stretched compressed form shown in Figure 8, but the loop portion 30 may have a substantially circular shape in the relaxed expanded form, as shown in Figure 6. In some examples, the loop 130 may have a diameter between 1 mm and 5 mm in the relaxed expanded form. In other examples, the loop 130 may have a diameter between 2 mm and 3 mm.

[0041] The proximal end 14 of the stent 10 may be formed by a series of free loop portions 30. In some embodiments, a tether or suture 27 may be inserted through the free loop portion 30 at the proximal end to facilitate the removal of the stent 10. The retrieval suture 27 may be used to fold and retrieve the stent 10 if necessary. For example, the retrieval suture 27 may be pulled like a drawstring to radially fold the proximal end 14 of the stent 10 to facilitate the removal of the stent 10 from the body lumen. The size of the free loop portion 30 at the proximal end may be increased or decreased, respectively, to increase or decrease the amount of internal tissue growth at the proximal end achieved during stent implantation.

[0042] As shown in Figure 9, in the relaxed expanded form, the struts 26 form the outer surface 40 of the stent 10, and the intersecting base region 32 of the twisted knitted stitches 22 extends radially outward from the outer surface 40. The intersecting base region 32 forms a raised ridge 34 that extends spirally around the stent 10. In some examples, the spiral ridge 34 may have a longitudinal cross-sectional wave shape with a proximal inclination 35, a apex 36, and a pocket 37 facing the distal end 16 of the elongated tubular member. In some examples, the apex 36 may protrude between 0.5 mm and 5.0 mm from the outer surface 40. In certain examples, the apex 36 may protrude by 1.5 mm from the outer surface 40. This distance is essentially the diameter of the loop portion 30, and the minimum distance depends on the diameter of the filament 24. For filament 24, wires ranging from 3 / 1000 inch to 14 / 1000 inch (0.0762 mm to 0.3556 mm) can be used. In one example, a 6 / 1000 inch (0.1524 mm) wire was used as filament 24.

[0043] The spaces between the spiral ridges 34 can form channels 38 extending between the apex 36 of adjacent ridges 34. The channels 38 can provide a drainage mechanism for the stent 10. The ridges 34 can engage with the tissue wall, while at least a portion of the channels 38 can remain separated from the tissue wall, allowing for the drainage of bodily fluids along the entire length of the stent 10. Coverings or grafts placed on or within the stent may assist in forming the channels 38.

[0044] Figure 10 shows a portion of the stent 10 positioned with organ 42. The wave-like shape of the ridge 34 provides strong anti-migration properties in one direction and less so in the opposite direction. The stent 10 is loaded into a delivery sheath and, as shown in Figure 10, can be positioned within the organ of the body in a preferred direction to optimize resistance to migratory forces on the stent. This unique anti-migration mechanism may also offer advantages during stent removal, as it can pull the stent in the direction with less anti-migration properties during removal. This mechanism can facilitate stent removal by the physician without compromising any of the stent's overall strong anti-migration properties.

[0045] As shown in Figure 10, when a moving force 44 such as peristalsis acts distally on the stent 10 when it is placed in the stomach or intestine, the crest 36 of the wave provides resistance by being pressed against the organ wall 46, and the pocket 37 engages with a portion of the organ wall 46, thereby preventing the stent 10 from moving. The crest 36 has no sharp edges, barbs, or quills. Rather, as shown in Figure 9, the crest 36 forms a smooth but distinct edge. The anti-movement effect provided by the crest 36 is exerted for each ridge 34 that rises along the entire length of the stent 10. The waveform of the ridges 34, in particular the gentle slope 35 directed proximal, allows the stent 10 to be removed proximal without damaging the organ wall 46.

[0046] The twisted stitches 22, particularly the loop portions 30, can be configured to match the desired and / or required level of tissue internal growth. For example, increased tissue internal growth can be achieved by increasing the number of loop portions 30 around the circumference of the stent 10. The spiral pitch and / or angle can also be increased, as can the size of the loop portions 30. The configuration of the loop portions 30 can have a more significant effect on tissue internal growth in stents having a bare metal composition without any covering or grafts.

[0047] Peristalsis in the intestine occurs along the longitudinal surface of the organ wall. Existing parallel-woven stents have raised loops formed linearly along the entire length of the stent. Therefore, the force transmitted to such a stent by peristalsis acts constantly along the entire length of the stent in contact with the intestinal wall. However, the spiral ridges 34 of the stent 10 prevent the force from being directly transmitted along the entire length of the stent in contact with the intestinal wall. Instead, the organ wall 46 exerts force against the raised ridges 34 of the stent 10, but this force is intermittent because it is not transmitted to the outer surface 40 formed by the ribs 26 of the stent 10.

[0048] The configuration of a braided pattern, as shown in Figure 8, which has helical properties, can allow the stent to "accommodate" additional wire loops in a closed, compressed form with defined radial and axial flexibility. In contrast, braided or parallel braids (Figure 4) are designed with a fixed amount of material to function and exhibit their properties. When a braided or parallel braided stent is stretched, the material must respond by reducing the diameter, radial force, or axial force. Figures 11A and 11B show the performance of a conventional braided stent 200 as it moves between a relaxed, expanded form (Figure 11A) and an extended form (Figure 11B). The braided stent 200 can accommodate length changes; for example, from an initial length of 50 mm in Figure 11A, the stent can be stretched by 30 mm, but this stretching results in a diameter reduction of 8 mm, as shown in the extended state in Figure 11B.

[0049] As shown in Figure 8, the elongation of the disclosed braiding pattern allows the stent to change length without significantly reducing its diameter and to maintain radial force, so that any excess material "contained" in the design can be effectively utilized as an "unrestricted" braid throughout the entire design range. Figures 12A and 12B show the performance of the disclosed braiding pattern (Figure 8) in the stent 10 as it moves between a relaxed, longitudinally contracted state (Figure 12A) and an elongated state (Figure 12B). The braided stent 10 can accommodate changes in length; for example, from an initial length of 50 mm in Figure 12A, the stent 10 can be elongated by 85 mm with a diameter change of 0 mm, as shown in Figure 12B. Therefore, the stent 10 may have a first longitudinal length and a first diameter in its relaxed, expanded state (Figure 12A), and a second longitudinal length and a second diameter in its extended state (Figure 12B), where the first longitudinal length is shorter than the second longitudinal length, and the first and second diameters may be substantially the same. As a result, the stent 10 can compensate for more movement between the two organs while maintaining a substantially constant lumen diameter that allows fluid flow through the stent, and may function better in mobile areas such as the HGS procedure described above. The stent 10 may behave like a spring in its deployed, relaxed, and fully expanded states. This is a property not found in conventional parallel-braided or woven metal stents.

[0050] As seen in Figure 12A, in the relaxed state, the stent 10 has a series of spiral ridges 34 made of twisted knitted stitches. As the stent 10 is partially stretched, the angle of the spiral ridges 34 increases, as shown in Figure 12B. As the stent 10 stretches, it may also twist, and the angle of the spiral ridges 34 may increase until the spiral ridges 34 become straight in a longitudinal columnar shape, as shown in Figure 7. As the stent continues to stretch from the configuration in Figure 12B to the configuration in Figure 7, its outer diameter may decrease. This may allow the stent 10 to be compressed within the delivery sheath 13.

[0051] During deployment, as the stent 10 is released from the delivery sheath 13, the stent 10 may twist in a corkscrew manner as it relaxes and moves from the delivery configuration in Figure 7 through the extended configuration in Figure 12B to the original relaxed spiral shape in Figure 12A. This corkscrew-like twisting motion during deployment can help both ends of the stent 10 engage with the organ wall. This spring-like expansion of the stent 10 means that the stent 10 resists the peristaltic forces acting on it, moving between the extended configuration in Figure 12B as the organ to which the stent is fixed moves relative to each other during digestion, and then returns to the original relaxed configuration and / or relaxed position in Figure 12A after peristaltic movement and expansion during digestion have occurred. As the stent 10 experiences peristaltic movement pushing along the stent 10, a portion of the stent 10 expands radially prior to the movement, similar to a spring. Once the peristaltic movement has passed the length of the stent 10, the stent 10 begins to return to its original position.

[0052] In some embodiments, the first end region 23 may include a retaining mechanism or anti-movement flare region having an enlarged diameter relative to the intermediate region 18, as shown in Figure 13. In other embodiments, the second end region 28 is flared. Alternatively, both the first end region 23 and the second end region 28 may include a flared region. The flared end region may include a gradual increase in outer diameter, as shown in Figure 13. In other embodiments, the change between the diameter in the intermediate region 18 and the diameter in the first end region 23 and / or the second end region 28 may be steeper. The anti-movement flare region may be configured to engage with the inner portion of the wall of the stomach, hepatic duct, or other body lumen. The transition from the cross-sectional area of ​​the intermediate region 18 to the retaining mechanism, i.e., the flared region, is envisioned to occur in a gradual, inclined, or abrupt stepwise manner, as desired.

[0053] In some embodiments, the first anti-movement flare region may have a first outer diameter, and the second anti-movement flare region may have a second outer diameter. In some examples, the first and second outer diameters may be substantially the same, while in other examples, the first and second outer diameters may be different. In some embodiments, the stent 10 may include only one anti-movement flare region or not include any at all. For example, the first end region 23 may include an anti-movement flare, while the second end region 28 may have an outer diameter similar to that of the intermediate region 18. Furthermore, it is conceivable that the second end region 28 may include an anti-movement flare, while the first end region 23 may have an outer diameter similar to that of the intermediate region 18.

[0054] Stent 10 may be manufactured in accordance with the method described in U.S. Patent Application Publication No. 2020 / 0214858(A1), the entirety of which is incorporated herein by reference.

[0055] Figure 14 illustrates a stent 10 as described above, having a first end implanted in the stomach 150 and a second end implanted in the hepatic duct 162 for hepatogastric anastomosis (HGS) to drain bile into the stomach.

[0056] Similarly, stent 10 may be used in gastrojejunal (GJ) bypass surgery. One GJ procedure involves inserting one end of stent 10 into the stomach wall and the other end of stent 10 into the distal portion of the small intestine 6, as shown in Figure 15. Stent 10 creates an anastomosis between the small intestine 6 and the stomach 150, as shown in Figure 15, effectively diverting gastric contents directly into the small intestine. Since both the stomach wall and the intestine experience peristalsis, this is considered a highly mobile application where benefits from stent 10 can be obtained, in which case bypass can be achieved while allowing an adaptable channel that maintains its diameter throughout peristalsis.

[0057] The stent described above can also be used to form a stoma within the intestinal tract. A stoma is an artificial opening formed in the large intestine or another region of the digestive tract during surgery to bring the large intestine above the surface of the abdomen. A loop stoma is formed when a loop of the large intestine is opened through the abdominal wall, exposing its two ends. The stent 10 described above can be used to connect the skin surface 1 to the large intestine 8. The use of a stent offers the advantage of leaving the large intestine 8 inside the body and requiring a smaller opening to the large intestine. Furthermore, the stent 10 eliminates the need to move a portion of the large intestine 8 through the abdominal wall to the skin surface 1. In other embodiments, a stent 300 with one or more flanges 311 added may be used. As shown in Figure 16, the flange 311 in the first end region 302 of the stent 300 may be positioned on the skin surface 1. In some embodiments, a second flange may be positioned on the inner surface of the skin or abdominal wall to further secure the stent 300 to the skin surface 1. The second end region 304 of the stent 300 may be inserted coaxially into the large intestine 8. In some embodiments, the second end region 304 of the stent 300 may include an outward-facing flared region 306 to further secure the stent within the large intestine 8. The stent 300 may accommodate all movements of the large intestine 8 during peristalsis. In some embodiments, the stent 300 may be coated with a liquid-impermeable coating so that the contents of the large intestine are directed through the stent 300 in the direction indicated by arrow 7. In some embodiments, the entire stent 300 may be coated. This may be desirable when the stoma is temporary and the stent 300 is to be removed after a certain period of time. In other embodiments, such as when the stoma is permanent, a portion of the second end region 304 may be left uncovered (exposed) to allow for internal tissue growth.

[0058] A further application of using the stent 10 as a bridging device between two separated organs may be its use as part of an EDGE procedure. Internal EDGE (EUS-Directed trans Gastric ERCP) procedure is a novel technique developed to perform ERCP entirely endoscopically in Roux-en-Y gastric bypass (RYGB) patients. In RYGB, the surgeon separates the upper and lower parts of the stomach. The upper portion or pouch 152 is then connected to the periphery of the small intestine 158. See Figure 17. The excluded gastric portion 156 and duodenum 154 are effectively removed from the digestive process. In patients who have undergone RYGB, conventional ERCP is no longer possible because the bile duct 164 is no longer accessible through the pouch 152.

[0059] Currently, the standard treatment involves a combination of surgical and endoscopic procedures to access the bile duct. The surgical portion of this procedure can be avoided by temporarily reversing the bypass in the patient using a stent 10, as described above, to allow for the performance of conventional ERCP. The stent 10 can be inserted between the pouch 152 and the excluded gastric portion 156, as shown in Figure 17, so that an endoscope 400 can pass through the pouch 152 and stent 10 into the excluded gastric portion 156 and duodenum 154, providing temporary access to the bile duct 164. Once the need for ERCP is complete, the stent 10 can be removed, and the anatomical structure of the bypass can be restored by endoscopic suturing. The entire procedure can be performed entirely from inside the body using an endoscope and can be done on an outpatient basis. The proximity and relative motility between the RYGB pouch 152 and the excluded gastric portion 156 can be effectively bridged by the stent 10.

[0060] Stents, delivery systems, and their various components may be made from metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, ceramics, combinations thereof, etc., or other suitable materials. Some examples of suitable metals and metal alloys include stainless steels such as 304V, 304L, and 316LV stainless steels, mild steels, nickel-titanium alloys such as linear elastic and / or superelastic Nitinol, other nickel alloys such as nickel-chromium-molybdenum alloys, nickel-copper alloys, nickel-cobalt-chromium-molybdenum alloys, nickel-molybdenum alloys, other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, cobalt-chromium alloys, cobalt-chromium-molybdenum alloys, platinum-reinforced stainless steels, titanium, combinations thereof, etc., or other suitable materials.

[0061] Other examples of suitable polymers for stents or delivery systems include polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN® available from DuPont), polyether block esters, polyurethane (e.g., polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyether esters (e.g., ARNITEL® available from DSM Engineering Plastics), ether or ester-based copolymers (e.g., butylene / poly(alkylene ether) phthalates and / or other polyester elastomers (e.g., HYTREL® available from DuPont), polyamides (e.g., DURETHAN® available from Bayer, or CRISTAMID® available from Elf-Atochem), elastomer polyamides, block polyamides / ethers, polyether block amides (PEBA, e.g., available under the trade name PEBAX®), and ethylene Polyvinyl acetate copolymer (EVA), silicone, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low-density polyethylene (e.g., REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxy Poly(PPO), poly(p-phenylene terephthalamide) (e.g., KEVLAR®), polysulfone, nylon, nylon-12 (GRILAMID®, available from EMS American Grillon, etc.), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS50A), polycarbonate, ionomer, biocompatible polymer,It may include other suitable materials, or mixtures, combinations, copolymers, polymer / metal composites, etc.

[0062] In at least some embodiments, part or all of a stent or delivery system may also be doped, fabricated, or otherwise contain radiopaque material. Radiopaque materials are generally understood to be materials that are opaque to RF energy in the wavelength range spanning X-rays to gamma rays (<0.005 inches (0.127 lims) thick). These materials can produce a relatively dark image on the fluoroscopic screen compared to the bright image produced by non-radiopaque materials such as tissue. This relatively bright image helps the user of the stent or delivery system determine its location. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, and polymer materials filled with radiopaque fillers. In addition, other radiopaque marker bands and / or coils may also be incorporated into the design of the stent or delivery system to achieve the same result.

[0063] It should be understood that this disclosure is, in many respects, merely illustrative. Modifications may be made without exceeding the scope of the invention, particularly with respect to details, especially shape, size, and process arrangement. This may include, to a suitable extent, the use of any of the features of one exemplary embodiment used in other embodiments. The scope of the invention is, of course, defined in the language in which the appended claims are expressed.

Claims

1. A stent configured to connect two separated anatomical locations, An elongated tubular member having a longitudinal axis, comprising an elongated tubular member having a lumen extending from the proximal end to the distal end, wherein the elongated tubular member comprises at least one woven filament having a rib to form a plurality of twisted stitches, the rib extending circumferentially between radially adjacent twisted stitches, each twisted stitch being interconnected with longitudinally adjacent twisted stitches forming a series of connected stitches, and the elongated tubular member being configured to move between a relaxed state and an extended state. Each of the aforementioned multiple twisted knitted stitches is formed by a single filament that forms a base region intersecting with the loop portion. A stent comprising the elongated tubular member having a first longitudinal length in the relaxed state and a second longitudinal length in the extended state, wherein the first longitudinal length is shorter than the second longitudinal length, and the elongated tubular member having a first outer diameter defined by the struts in the relaxed state and a second outer diameter defined by the struts in the extended state, wherein the first outer diameter and the second outer diameter are substantially the same.

2. The stent according to claim 1, wherein the elongated tubular member has a coating that covers at least 70% of the length of the elongated tubular member, and the coating extends continuously over the first outer diameter and the second outer diameter.

3. The stent according to claim 1 or 2, wherein at least some of the loop portions of the twisted stitches are wrapped around the intersecting base regions of longitudinally adjacent twisted stitches.

4. The stent according to claim 1 or 2, wherein, when in the relaxed state, the struts form the outer surface of the elongated tubular member, and the intersecting base regions of each twisted knitted stitch extend radially outward from the outer surface.

5. The stent according to claim 4, wherein the intersecting base regions form a raised ridge that spirally extends around the elongated tubular member in the relaxed state.

6. The stent according to claim 1 or 2, wherein the at least one braided filament is a single braided filament.

7. A stent for connecting two separated anatomical locations, The device comprises an expandable stent positioned between a first anatomical structure and a second anatomical structure, configured to provide fluid communication between the first and second anatomical structures, the stent, The material comprises an elongated tubular member having a longitudinal axis, the elongated tubular member comprising at least one woven filament having a rib to form a plurality of twisted stitches, the rib extending circumferentially between circumferentially adjacent twisted stitches, each twisted stitch being interconnected with longitudinally adjacent twisted stitches forming a series of connected stitches, and configured to move between a relaxed state having a first longitudinal length and an extended state having a second longitudinal length greater than the first longitudinal length, having a first outer diameter defined by the rib in the relaxed state and a second outer diameter defined by the rib in the extended state, the first and second outer diameters being substantially the same. Each of the aforementioned twisted knitted stitches is formed by a single filament that forms a base region intersecting with the loop portion. The stent comprises an elongated tubular member having a liquid-impermeable coating extending at least 70% of the length of the elongated tubular member.

8. The stent according to claim 7, wherein the first end of the stent includes a flange.

Images