Suction stent

Abstract

The present invention relates to a stent for introduction into a hollow organ which can be used to provide vacuum sealing of leaks to specific anatomical regions within the hollow organ for the treatment of anastomotic insufficiency.SOLUTION: The stent comprises a radially expandable body 12 having a wall defining an internal fluid passageway 18, a fluid-tight and flexible first layer 20 covering the surface of the wall along its entire circumference and along a first predetermined area, and an elastic and porous second layer 22 covering the outer surface of the wall along its entire circumference and along a second predetermined area and at least partially covering the first layer 20. Further, the first layer 20 is disposed on the wall surface and extends radially through the wall and / or the second layer 22 is mechanically secured to the body 12.SELECTED DRAWING: Figure 1

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to a stent for introduction into a hollow organ of a human or animal patient, particularly into the gastrointestinal tract. Such a stent may be used, inter alia, to provide vacuum sealing of leaks in specific anatomical regions within the hollow organ, for example for the treatment of localized anastomotic failure.

[0002] [Background technology] Leaks in surgical anastomoses (anastomoses) in the gastrointestinal tract are the most dangerous and therefore constitute one of the most serious complications after abdominal surgery. When a leak occurs, stomach or intestinal contents enter the abdominal cavity, resulting in peritonitis, which remains fatal in approximately 20% of cases today. Treating such a leak depends on the exact location and damage already caused by the leaked intestinal contents. In the best case scenario, healing of the anastomosis is delayed, impairing the functional results of the surgery, such as continence. However, often, to avoid endangering the patient's life, fairly invasive methods are required, such as a reoperation involving removal of the intestinal continuity and the creation of a colostomy. The process of creating a colostomy is reversible only in a small number of cases.

[0003] For example, attempts to seal anastomotic defects using endoscopically placed intraluminal covered stents or other conventional stents have often been found to be unsuccessful in adequately sealing sutures in hollow organs. This inadequacy can generally be attributed to a mismatch between the applied stent and the irregularly shaped bowel wall. Self-expanding stents with high resilience cannot be used to achieve complete sealing in the area of ​​leaking sutures, as this can result in further damage or even rupture of the sutures.

[0004] Furthermore, even if complete sealing of the defect is actually achieved in exceptional cases, it is not possible to evacuate the contents of the hollow organ that has entered the area of ​​the suture, such as the contents of the intestine. Therefore, the formation of abscesses at the sutures is virtually inevitable, especially in the gastrointestinal tract, thereby resulting in local pathological conditions and further deterioration of the patient's medical condition.

[0005] The implementation of porous foam has been proposed to improve the sealing of the walls of hollow organs, such as the intestine. The porous foam can be placed on the outside of the stent body and held in place by the radially outward pressure exerted by the stent body. Furthermore, evacuation of harmful contents from the corresponding hollow organ can be achieved by providing a cannula on the outside of the stent body, for example, within the porous material. This can further result in improved sealing of sutures by applying a vacuum, or even replace the need to apply sutures to close the lesion until it heals.

[0006] However, it has been found that after prolonged use of the stent, local tissue ingrowth can occur. In particular, porous materials and typically mesh-like stent bodies appear to be the most susceptible. Due to the accelerated healing process of (leaking) sutures and therefore the preferably temporary nature of the stent application, removal or retraction of the stent can constitute an additional challenge in avoiding damage to the surrounding tissue.

[0007] Thus, there is a need to further improve current stents in terms of patient safety and therapeutic efficacy, both during and after stent application.

[0008] Summary of the Invention Therefore, starting from the known prior art, it is an object of the present invention to provide a stent that effectively seals a local defect, such as a leaking surgical suture, and at the same time facilitates removal after prolonged use. Preferably, such a stent also allows for the effective removal of any accumulation of fluid in such a defect in a hollow organ of the human or animal body.

[0009] This object is achieved by the stent of the invention according to the independent claims. Preferred embodiments are set out in the dependent claims, the description and the drawings.

[0010] Thus, a stent for introduction into a hollow organ of a human or animal body, preferably into the gastrointestinal tract, particularly into the intestine, is proposed. The stent comprises a radially expandable body having a wall defining an internal fluid passageway from one end of the body to the opposite longitudinal end of the body. The stent further comprises a first fluid-tight, flexible layer and a second elastic, porous layer. The first layer covers the surface of the wall along its entire circumference and along a first predetermined longitudinal region of the body. The second layer covers the outer surface of the wall along its entire circumference and along a second predetermined longitudinal region of the body, and at least partially covers the first layer. The first layer is disposed on the wall surface and extends radially at least partially through the wall, and / or the second layer is mechanically fixed to the body.

[0011] The radial extension of the first layer through the wall can fill any pores or cavities present in the wall, resulting in the wall being at least partially embedded in the first layer. This ensures and maintains direct contact with the wall during stent deployment, thereby improving the sealing function of the first layer against the fluid passageway and the outside. Furthermore, the radial extension through the wall provides mechanical stability to the first layer not only by partially increasing the thickness of the first layer, but also by anchoring the first layer to the wall in the radial, longitudinal, and circumferential directions.

[0012] Furthermore, local tissue ingrowth is reduced by protruding from or penetrating the wall. For example, the stent body may be mesh-shaped, i.e., have a wire structure, so that the radial extensions of the first layer fill the mesh. This essentially prevents local tissue from growing through or intertwining with the mesh-shaped structure of the stent body. This also applies to other types of stent bodies, for example, having a porous structure or a (continuous) pore pattern. Therefore, removal of the stent may be facilitated, and potential tissue damage upon removal may be reduced, while the improved mechanical or structural stability of the first layer ensures the sealing function during application of the stent.

[0013] Mechanically securing the second layer to the body also ensures that the stent can be safely removed even if limited local tissue ingrowth occurs through the porous structure, and that the second layer will not be left behind in the patient upon stent retraction. During application, mechanical fixation of the second layer ensures proper positioning of the second layer so that an improved seal against the interior wall of the hollow organ at the site of the lesion or suture is maintained, even during movement or contraction of the surrounding tissue.

[0014] Thus, both the configuration of the first layer extending radially through the wall and the fixation of the second layer to the stent body achieve effective sealing of the local tissue defect and facilitate removal of the stent after long-term use. These mechanisms can be used as alternative technical solutions. Meanwhile, these mechanisms synergistically improve safety during application and removal of the stent, so that the stent according to the present invention may include any of the alternatives, preferably including both the beneficial configuration of the first layer and the beneficial configuration of the second layer.

[0015] The fluid passageway of the body or stent body (similarly referred to throughout the present invention) can be understood as a through passageway or internal cavity with opposing openings. Thus, the body forms a longitudinally open hollow body with a lumen, allowing fluid to enter the passageway through one end and exit the passageway through the opposite end. The body is preferably essentially cylindrical or tubular in shape, but may also have other cross-sectional shapes, such as an elliptical shape, at least in one or more regions of the body. The body is preferably an elongated body with an essentially continuous longitudinal extension, but one or more curvatures may be present, which may, for example, allow the stent to adapt to specific anatomical structures depending on the respective application.

[0016] Preferably, the radially expandable body is mesh-shaped, which facilitates expansion and compression of the stent and provides a degree of conformance to the anatomical structure of the application area, e.g., the intestinal wall. The body may be formed from a shape-memory alloy, such as nitinol, which further facilitates collapsing the stent for delivery to the target lesion or suture via a delivery system and catheter. The body may also be configured to be self-expanding, which may be facilitated by the use of such shape-memory alloys or other metals. Such materials further provide the body with elasticity, thereby allowing it to conform to the local anatomical structure at the application site and, depending on the dimensions of the stent body, achieve retention of the stent in place by applying radial and / or longitudinal forces. While a shape-memory alloy may be preferred for structural stability, the stent body may alternatively be formed from a self-expandable plastic material.

[0017] The luminal diameter of the stent, i.e., the radially expandable body, according to the invention is preferably in the range of about 10 to 50 mm, preferably 15 to 35 mm, in particular 15 to 30 mm, and most particularly preferably about 28 mm (e.g., for applications in the colonic region) or about 21 mm (e.g., for use in the esophagus). In either case, the diameter of the stent is selected depending on the application area so as not to impede the passage of the corresponding material through the respective hollow organ (e.g., the passage of food in the case of the intestinal tract). The above dimensions may apply to the entire expandable body, while at least one of the opposing ends or end regions may have a greater radial extension, or the dimensions may be met by the opposing ends or end sections, with the section between the opposing ends being of a smaller dimension.

[0018] The liquid-tight, flexible first layer may also be elastic and / or compressible or foldable, so that the material integrity of the first layer is not adversely affected in the folded state, and the material facilitates expansion of the first layer, preferably in an essentially homogeneous manner, and preferably also facilitates or at least does not impair the expansion of the body. The liquid-tight first layer ensures that liquids outside the stent body cannot enter the fluid passages, and vice versa, so that bodily fluids in the hollow organ cannot inadvertently enter surrounding organs or enter the blood circulation.

[0019] Preferably, the first layer is liquid-tight or airtight. If the stent is equipped with a drainage means, such as a cannula, placed outside the first layer, this allows a vacuum to be applied between the first layer and the inner wall of the hollow organ. Any contents leaking into this intermediate space can thus be effectively evacuated by negative or suction pressure, and the (small) vacuum can further facilitate sealing of the lesion or suture, thereby accelerating the healing process.

[0020] The first layer may be formed from or may comprise a plastic or polymeric material, preferably selected from the group comprising polyurethane, latex and silicone. Preferably, the first layer is silicon-based.

[0021] The elastic, porous second layer is preferably moldable and / or compressible, while returning to its original, uncompressed state in the absence of compressive forces. The second layer may surround the stent body, e.g., be tubular with a central through-hole that accommodates the stent body and the first layer. The second layer may be formed as a closed-pore material, i.e., a foam, or as an open-pore material, i.e., a sponge. Preferred materials for this purpose are, for example, plastic foams containing or consisting of polyurethane, polyvinyl alcohol, or mixtures of such plastic materials.

[0022] The second layer preferably has a thickness of about 5 mm to about 20 mm, preferably about 5 mm to about 10 mm, the exact dimensions depending on the anatomical dimensions at the application site and the physical requirements, taking into account, for example, the required elasticity and the necessary bridging between the stent body and the inner wall of the hollow organ.

[0023] The entire structure of the stent according to the present invention is preferably fully expandable and can be moved by conventional application means to the application site in the organ, particularly the gastrointestinal tract, preferably the esophagus, intestine, mainly the rectum, sigmoid colon, descending colon or transverse colon.

[0024] The first layer may be disposed on the inner or outer wall surface and extend radially to fill at least the space between the surfaces to embed and mechanically secure the stent body to the first layer. Preferably, the first layer is disposed on at least the outer wall surface of the stent body. More preferably, the first layer covers both the inner and outer surfaces of the wall. The stent body, i.e., the wall of the stent body, is thereby completely embedded in the first layer. In contrast to a liquid-tight foil implementation, such a configuration results in a thicker material layer, effectively reducing leakage and unevenness and ensuring that the first layer is completely fixed to the stent body, which may preferably be in a mesh shape. Furthermore, such an embedded configuration and corresponding structural connection may prevent the first layer from folding, providing a more uniform outer shape and reducing the potential occurrence of wear during application.

[0025] Preferably, the first and / or second predetermined regions correspond to regions of the body having an essentially continuous cross-sectional area. Such an essentially continuous cross-sectional area may be provided throughout the entire region between the opposing ends, and may be, for example, tubular, circular, or elliptical. However, intermediate constrictions may be present, for example, to ensure mechanical stability or to provide conformance to an anatomical structure. The cross-sectional area may relate to the wall, the passageway, or both. Matching each predetermined region to a continuous cross-sectional area facilitates manufacturing and may also avoid bulging, folding, or wrinkling of the respective layers during expansion and / or application of the stent.

[0026] Thus, the first and second predetermined regions may essentially correspond to each other. Alternatively, the first layer may also extend longitudinally beyond the second layer at each end or end region of the stent body. For example, the stent may comprise drainage means, e.g., in the form of a cannula, housed along the stent body but guided through the stent body at each end region. To ensure that the fluid passages of the stent body are liquid-tight at the corresponding end region while the drainage means extend through the corresponding wall surface, the first layer may not be applied to the end region, and other means for maintaining the liquid-tight configuration may be provided in the end region. For example, a liquid-tight, preferably fluid-tight, foil may be provided on the inner wall surface of the end region and continuous with the first layer, as described in more detail herein below. The drainage means or cannula may be located outside the foil and at least partially between the wall and the foil in the end region.

[0027] The first and / or second predetermined regions may be longitudinally defined by at least one end region of the body, the at least one end region having an enlarged radial extension.

[0028] At least one end region, preferably both opposing end regions, may have, for example, a varying cross-sectional area or shape and / or exhibit a radial increase immediately adjacent to a region of the stent body having an essentially continuous cross-sectional area. If one of the end regions is configured to receive a drainage means or cannula, the first layer may be defined by said end region, and instead, a foil, e.g., a tubular foil, may be disposed on the inner wall surface, as described above. Such a foil is preferably fluid-tight, i.e., airtight and watertight, and may be formed, for example, from polyurethane, latex, and / or silicone or silicon-based materials. To form a homogeneous and structurally stable sealed structure, the foil may be secured to the first layer by a sealing agent, particularly a hydrogel, such as silicone, a hydrocolloid, or a lyogel.

[0029] The second layer may at least partially cover each end region, as long as the overall radial extent of the second layer remains essentially constant. For example, if the end region gradually increases in radial extent, the thickness of the second layer may decrease accordingly, until it reaches zero. This results in a smoother transition between the (outer) second layer and the radially protruding end region.

[0030] Each end region may have a mushroom, dome, toroidal or donut shape in longitudinal cross section of the body, and the entire body may therefore have a barbell shape.

[0031] These particular shapes provide rounded surfaces without sharp edges, thereby reducing the risk of injury to adjacent tissue, for example, during deployment or movement of the stent body. Furthermore, the rounded shape provides improved conformance to the local anatomy of the application site, i.e., better conforming to the inner wall of the hollow organ while exhibiting elasticity that holds the stent securely in place at the application site.

[0032] In this regard, the enlarged radial extension at both opposing end regions also allows the stent to be positioned such that a lesion or suture is placed between the respective end regions, thereby facilitating or improving the targeted application of vacuum or evacuation at this particular location.

[0033] Both the first and second predetermined regions may be further defined by opposing end regions. Thus, the first and second predetermined regions may essentially have the same longitudinal extension. However, as described above, the second layer may at least partially cover the respective end regions, as long as its thickness is appropriately reduced. Furthermore, each end region may be configured to receive and accommodate a drainage means, and instead of the first layer, a liquid-tight foil may be mounted within the fluid passage or beneath or on the inner wall surface. However, the opposing end regions not receiving such drainage means may optionally be at least partially covered and embedded with the first layer.

[0034] The definition of the second layer by both opposing end regions may further provide that the second layer is mechanically secured in a shape-fitting manner by the opposing end regions in the longitudinal direction. Depending on the dimensions and material type of the second layer, a loose shape fit may be provided, for example, so that radial or longitudinal forces acting on the second layer may still result in a corresponding shift. However, the boundary provides that, at least during stent deployment, the second layer is biased between the opposing end regions to ensure proper application of the stent to the target site.

[0035] Depending on the dimensions of the second layer and the materials used, the second layer may be somewhat secured to the stent body (or first layer), for example, rotationally and / or longitudinally, by a friction fit or press fit.

[0036] To provide improved fixation of the second layer to the stent body, the second layer may be mechanically attached to the body by at least one thread, a first thread portion being arranged in the second layer so as to provide at least one small hole in the outer surface of the second layer, and a second thread portion connecting the at least one small hole to respective connection points in the end regions of adjacent bodies not covered by the second layer.

[0037] The adjacent end region is preferably not covered by the first layer, as it receives and accommodates the drainage means. This may facilitate connecting the second thread portion to the corresponding end region, preferably the proximal and / or nearest end region. To improve the structural stability of the second layer, the at least one eyelet is preferably spaced longitudinally from the end face of the second layer corresponding to the corresponding end region. Preferably, the at least one eyelet may be located between about 5 mm and about 20 mm, preferably between 8 mm and 15 mm, or about 10 mm, from the corresponding end face.

[0038] The threads may be made of a biocompatible but non-biodegradable material, such as a suture material. Preferably, the threads are made of polyethylene (PE), polypropylene (PP), or polytetrafluoroethylene (PTFE). The connection to the connection points may comprise corresponding knots at the connection points, for example, at the intersecting struts of the mesh-shaped body, or may be provided via loops to provide threaded fixation. By the connection, the second layer is fixed both radially and longitudinally.

[0039] Preferably, at least two eyelets are provided by the first thread portion, said eyelets being circumferentially spaced apart. In this way, potential movement of a portion of the second layer, i.e., in the longitudinal and / or radial directions, can be reduced. The second thread portion can connect each eyelet individually to a respective connection point, or can connect the eyelets to each other via one or more connection points, for example using corresponding loop and threading techniques.

[0040] Preferably, the eyelets are evenly spaced around the circumference, and / or three to six or four eyelets are provided by the first thread portion. Both the even spacing and the plurality of eyelets reduce the stress acting on the second layer due to mechanical attachment, effectively avoiding stenosis. For example, providing four eyelets at approximately 90° offsets around the circumference allows the second layer to be pulled in an evenly distributed manner toward the stent body without making the mechanical attachment too cumbersome. However, depending on the requirements of the stent and the configuration of the second layer used, additional eyelets may be provided.

[0041] Various connection methods may be provided, such as using loops and / or knots for multiple connection points and eyelets. Preferably, the second thread portions alternate between adjacent connection points and eyelets, and / or each connection point is connected by a second thread portion to two adjacent eyelets.

[0042] Thus, each eyelet may be connected to two adjacent connection points. The alternating pattern should be understood, for example, as a zigzag pattern between the circumferential lines formed by the connection points and the circumferential lines formed by the eyelets. Each connection may be formed by a knot or a loop, for example, by threading a second thread portion through the eyelet and guiding the second thread portion around the connection point. Thus, when a connection point is formed by an intersection of connecting struts in the wired mesh configuration of the stent body, the second thread portion may be guided from a corresponding eyelet around an adjacent strut or intersection of struts in the end region and further guided toward a further adjacent eyelet, thereby forming a loop between the eyelets via the connection point. For such purposes, connection points may also be specifically formed on the outer surface of the stent body, for example, in the form of a rounded protrusion having or defining a retaining element, a kerf, or a slit, as well as a corresponding eyelet.

[0043] As noted above, the end regions may have greater radial extension, e.g., mushroom-shaped, extending radially beyond the tubular region of the stent body having an essentially continuous cross-sectional area. Such a configuration may reduce the risk of narrowing the second layer (and potentially the stent body and / or first layer) and facilitate connection, as connection points may be more readily accessible. Preferably, although radial extension may be beneficial, the connection points are selected or positioned to minimize the radial extension of the second thread portions. This facilitates stent deployment and function and reduces any potential adverse effects on the structure of surrounding tissues in the implanted state.

[0044] To further improve force distribution and provide a more uniform and homogeneous attachment of the second layer to the stent body, each connection point may be positioned essentially equidistant to two adjacent eyelets. Thus, the connection points are preferably equally spaced around the circumference of the stent body and positioned essentially midway between two adjacent eyelets, but with a longitudinal offset. The equidistant placement of the connection points avoids biasing individual eyelets (and therefore the second layer) toward a particular connection point.

[0045] Between adjacent eyelets, the first thread portions can be disposed within the material of the second layer. Thus, the first thread portions can be guided through the second layer and embedded therein so that only the eyelets formed by the first threads protrude from the second layer. Such a configuration has the advantage that the larger first thread portions between the eyelets, adapted to both the collapsed or compressed state of the stent and the expanded state, are retained in the second layer and therefore do not unintentionally form loops, bends, or other folds that could impair the proper expansion and functionality of the stent, for example, by potentially interacting with the anatomical structure of the application site or other components of the stent. Furthermore, the internal first thread portions reduce the amount of thread portion that comes into contact with surrounding tissue, thereby reducing friction or dissection against the tissue. Furthermore, the potential for tissue infiltration or ingrowth around the first thread portions is also reduced.

[0046] Although the first and second thread portions may be formed as separate threads, it is preferred that the first and second thread portions be formed from a single thread. In other words, the first thread portion may be disposed in and / or within the second layer to provide one or more eyelets and continue as a second thread portion connecting the eyelets to respective connection points. For example, the first thread portion may be guided through the second layer, with only its front end protruding from the second layer to form a respective eyelet, e.g., by forming an outer loop, and its rear end forming the first eyelet by one or more ties to the first thread portion at the rear end. After the last eyelet, the front end of the first thread then continues as a second thread portion, connecting the respective eyelets via one or more connection points, e.g., in an alternating zigzag pattern.

[0047] The use of one and the same thread, i.e., a single thread, may allow fewer knots to be required. This may be physiologically beneficial because the occurrence of biasing of the second layer and / or stent body may be reduced and there may be fewer knots resulting in a smoother outer surface of the stent. Furthermore, the use of a single thread may be beneficial due to the overall structural stability of the thread.

[0048] The attachment of the second layer may be provided at either end region of the stent body, although the adjacent end region is preferably configured to accommodate a cannula. Thus, the adjacent end region may correspond to the proximal end region of the stent. This is particularly beneficial during removal and retraction of the stent, as frictional and / or tension forces are particularly experienced at this end, and thus the second layer is attached directly to said end to reduce potential leverage or longitudinal shift or folding of the second layer toward the distal end.

[0049] Thus, the stent may further comprise a cannula disposed between the second and first layers and essentially housed outside the body. The cannula or drainage means may generally be connected to the second layer and / or the stent body to ensure proper positioning of the cannula within the stent, i.e., between the opposing ends or end regions. The cannula may be connectable to a vacuum or negative pressure source, for example, to create a vacuum between the first layer and the inner wall of the hollow organ in the implanted and deployed state. However, other functions may optionally, and preferably additionally, be achieved using the cannula, such as by allowing rinsing or flushing of the application site, e.g., with saline or other biologically compatible fluid, or by applying a liquid or gel-like tissue sealant to promote healing of lesions or leaking sutures.

[0050] The cannula may be received through end regions having a radial extension greater than the fluid passageway to minimize the radial dimensions of the stent and passageway, for example, the end regions may be mushroom- or dome-shaped such that the cannula is introduced through the passageway and extends through the wall of the end regions to be received and housed along the outside of the stent body between the end regions.

[0051] According to a further aspect of the present invention, there is proposed a delivery system for delivering and deploying a stent in a target anatomical region, comprising a catheter having a stent according to the present invention in a compressed state. Preferably, the delivery system is configured, dimensioned and adapted to allow navigation and delivery of the stent to an application site in a patient's gastrointestinal tract, preferably the esophagus, intestine, primarily the rectum, sigmoid colon, descending colon or transverse colon.

[0052] Preferably, the catheter includes a distal end cap made of a flexible material, the end cap defining an internal cavity and having a longitudinally convex, rounded end face with at least three, and preferably four, equally spaced circumferential slits extending from its outer surface toward the internal cavity.

[0053] A small opening can thereby be formed for the guidewire, and the corresponding guide or end bead can be reduced in diameter, which is beneficial to the patient and in terms of the preferred minimally invasive method. The slits create a corresponding number of flaps on the end face, which, due to the flexible material, can be biased toward an open position or a radially and longitudinally outward position, providing a continuous through-hole for a compressed and / or folded stent. In this regard, a configuration with four slits provides greater flexibility and reduces the forces opposing deployment and guidance of the stent from the catheter.

[0054] For example, an end cap with three or more slits can therefore be smaller in size than a single-slit design, which has a limited end face opening to the internal cavity and therefore requires a larger slit and end face. This is also true in comparison to a pivotable design, where the closure in the end cap must open beyond the radial extent of the actual opening and therefore requires a larger size.

[0055] Compared to such configurations, the end caps according to the present invention also significantly facilitate operation of the delivery system, as the slits readily respond to the advancement of the stent from the catheter, without requiring further actuation.

[0056] The shape of each end face defined by two circumferentially adjacent slits may be further truncated at its free end. In other words, as described above, the slits may be arranged adjacent to one another circumferentially and define flaps separated solely by the slits. These flaps, which may have an essentially triangular shape, are attached to the end face at only one end of the flap, with the corresponding free end located at the intersection of the slits. The flap end at such intersection may be truncated or rounded to provide a (small) opening toward the internal cavity. This further facilitates catheter advancement and reduces friction at the free end. Therefore, more reliable biasing toward the open position and more reliable closure of the end cap toward the internal cavity may be achieved.

[0057] BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: FIG. 1 is a schematic diagram of a longitudinal cross section of a stent according to the present invention. FIG. 2 is a reduced schematic view of the stent according to FIG. 1 from the distal end region to the proximal end region. FIG. 3 is a stretched view of the wall of the stent body having the first layer configuration. FIG. 4 is a stretched view of the wall of a stent body having an alternative first layer configuration. FIG. 5 is a stretched view of the wall of a stent body having the first layer configuration according to FIG. FIG. 6 is a schematic end cross-sectional view of a catheter having an end cap at its distal end in longitudinal cross-section. FIG. 7 is a view of the embodiment according to FIG. 6 viewed longitudinally from the distal end.

[0058] Preferred Mode for Carrying Out the Invention The present invention will now be described in more detail with reference to the accompanying drawings, in which like elements are designated by like reference numerals and repeated description may be omitted to avoid redundancy.

[0059] In Figure 1, a schematic diagram of a stent 10 according to the present invention is shown in longitudinal cross section. Stent 10 is fully expandable and adapted to be moved by conventional application means to an application site in a hollow organ, particularly the gastrointestinal tract, preferably the esophagus, intestine, primarily the rectum, sigmoid colon, descending colon, or transverse colon. Stent 10 comprises a body 12, which, according to this non-limiting embodiment, is formed from a shape-memory material, preferably nitinol, and has an essentially continuous wired mesh configuration (not shown in Figure 1 to improve clarity of the various features of stent 10). Thus, body 12 is formed from an elastic, compressible, and foldable material and may be self-expandable, although other configurations allowing for mechanical expansion may also be provided.

[0060] The body 12 has an essentially tubular shape, has an essentially continuous cross-sectional area for the greatest portion of the body 12, and extends longitudinally from the proximal end 14 to the distal end 16. The terms proximal and distal should be understood to refer to the portions closest to the insertion site and the application site, respectively, during a surgical procedure for delivering the stent 10 to the application site. The continuous cross-sectional area is defined by the proximal end region 14 and the distal end region 16, which have various diameters and radial extensions, the radial extension of which exceeds the radial extension of the continuous cross-sectional area of ​​the body 12 for the greatest portion. The greater radial extension facilitates anchoring the stent 10 during deployment within a hollow organ and may further define, for example, a lesion or suture disposed between the proximal end 14 and the distal end 16, thereby effectively isolating the lesion or suture. Both the proximal end 14 and the distal end 16 have a toroidal or mushroom shape, which has a rounded or convex surface, providing a degree of conformability to the surrounding tissue at the application site, with sufficient radial extension to ensure that the stent 10 is properly secured in place.

[0061] From the proximal end 14 to the distal end 16, the body 12 or its wall further defines a continuous fluid passageway 18. The passageway 18 is fluid-tight and sealed against the inner wall of the hollow organ at the application site by a first layer 20, which may be formed, for example, from a silicon-based material. The first layer 20 ensures that an isolated lesion or leaking suture is no longer susceptible to contamination with the contents of the hollow organ, e.g., the intestine, and vice versa, so that potential high-risk medical complications can be effectively avoided. Sealing against the inner wall of the hollow organ is further facilitated by a second layer 22. The second layer 22 surrounds the first layer 20 and may be formed from a biocompatible foam or sponge material to provide sufficient moldability and conformability to the local tissue and anatomical structures at the application site. Such a material may also help mechanically secure the stent 10 at the desired application site. The continuous cross-sectional area preferably defines a first predetermined area of ​​the first layer 20 and a second predetermined area of ​​the second layer 22 .

[0062] The improved sealing provided by the passageway 18 and the end regions 14, 16 in addition to the first and second layers 20, 22 may allow normal function of the hollow organ to be established while promoting healing of lesions or leaking sutures, e.g., anastomoses.

[0063] In this embodiment, the body 12, or a region of the body 12 having a continuous cross-sectional area, is completely embedded in the first layer 20. The mesh-shaped structure of the body 12 allows the material of the first layer to extend radially from one side of the wall of the body 12 to the opposite side of the wall, e.g., from the inner wall to the outer wall, as described in more detail below with reference to Figures 3-5. The embedded configuration mechanically secures the first layer 20 to the body 12, improving the structural stability of the first layer 20. Therefore, proper function of the stent 10 and fluid-tight isolation of the lesion or suture can be ensured even after extended application times or deployment in complex tissue structures. Furthermore, the embedding ensures that tissue ingrowth toward or around the mesh-shaped body 12 can be effectively avoided or at least reduced.

[0064] Proper positioning and function of the second layer 22 is further ensured by a plurality of eyelets 24 formed by corresponding first thread portions and spaced evenly around the circumference of the second layer 22. The eyelets 24 may be formed, for example, by a suture material such as PP, PE, or PTFE, or may be formed as a braided material. Each eyelet 24 is further connected to the body 12 via a respective connection point 26 using a second thread portion 28, with the first thread portion 24 and the second thread portion 28 preferably being formed from a single continuous thread. The connection points 26 are located in the proximal end region 14, preferably at respective points having a radial extension greater than the radial extension of the eyelets 24.

[0065] The mechanical fixation allows the second layer 22 to be safely removed along with the other components of the stent 10 when the application is terminated, avoiding the second layer 22 from remaining within the hollow organ due to potential tissue ingrowth. Additionally, the mechanical fixation facilitates proper positioning of the second layer 22 during deployment of the stent 10.

[0066] 1 also shows a cannula 30 that is received in the proximal end region 14 and introduced through the wall of the body 12 so as to be housed along the body 12 between the proximal end region 14 and the distal end region 16. The proximal end 14 is not provided with the first layer 20 or the second layer 22 in order to facilitate the introduction of the cannula 30 and the manufacture of the entire stent 10. However, a liquid-tight foil (not shown) may be connected to the first layer 20 in this region, e.g., by having a tubular or conical shape, to ensure an adequate seal in this region as well, thereby covering the entire (inner) circumference of the toroidal-shaped proximal end region 14.

[0067] 2 shows that the second thread portions 28 may alternate between the eyelets 24 and the connection points 26, forming a zigzag pattern. While the different layers are scaled down in the figure for simplicity (and the first layer 20 and stent body 10 are not explicitly shown to improve the overview), it should be understood that the connection points 26 are located at curved portions of the proximal end region 14 having gradually increasing radial extensions. Furthermore, the body 12 is preferably formed as a mesh-shaped body 12, so that the connection points 26 may be formed by intersecting wires or struts, and the second thread portions 28 may be tied or bound at said intersections or guided or threaded around said intersections to form loops between two adjacent eyelets 24.

[0068] In this embodiment, four eyelets 24 are provided, and the eyelets 24 are equally spaced around the circumference of the second layer 22. The eyelets 24 may be formed as protruding loops of corresponding first thread portions 24 located within the second layer 22 between the eyelets 24. The connection points 26 are also equally spaced around corresponding circumferences of the body 12 in the proximal end region 14, with each connection point 26 located midway between two adjacent eyelets 24 with a longitudinal offset. While this embodiment provides beneficial even force distribution and uniform mechanical fixation without constriction of the second layer 22 or the body 12, it should be understood that other connection patterns and configurations of eyelets 24 and / or connection points 26 may be provided depending on the requirements of the stent 10 and the application site.

[0069] 3-5, an alternative configuration of the first layer 20 is shown with respect to the wall 32 of the body 12. The wall thus comprises an inner wall surface 34 and an outer wall surface 36 with respect to the passageway 18, and comprises a plurality of (continuous) openings 38, which may be formed, for example, by a mesh-shaped configuration of the body 12.

[0070] In all embodiments, the body 12 or its wall 32 is embedded by the first layer 20. According to the embodiment of Fig. 3, the material of the first layer 20 is mainly arranged on the outer wall surface 36, but protrudes into the opening 38 so that the first layer 20 is mechanically fixed to the wall 32. However, the passage 18 may essentially not include any first layer 20. Thereby, the diameter of the passage 18 is not affected by the first layer 20, and blockage of the passage 18 is essentially avoided even in the event of (partial) loosening of the first layer 20.

[0071] An alternative configuration is shown in Figure 4, in which the material of the first layer 20 is located mainly on the inner wall surface 34. This allows the radial extension of the second layer 22 to be increased, for example, or may be beneficial, when a liquid-tight foil is implemented in the proximal end region 14.

[0072] FIG. 5 shows a configuration in which the entire wall 32, ie the outer wall surface 36 and the inner wall surface 34, is embedded with the material of the first layer 20, which is also shown diagrammatically in the embodiment according to FIG.

[0073] 6 shows a schematic longitudinal cross-section of the end of a catheter 40 having an end cap 42 at its distal end. The catheter 40 and end cap 42 may be part of a delivery system for delivering and deploying a stent 10 to a target anatomical region, such that the stent 10 (not shown) is held within the catheter 40 in a compressed, and preferably folded, state during delivery and guidance toward the application site.

[0074] End cap 42 is formed of a flexible, and preferably elastic or stretchable, material and defines an interior cavity 46 for receiving a portion of catheter 40 during deployment of stent 10. Interior cavity 46 thus ensures that catheter 40 can be advanced through end cap 42 when catheter 40 is in place. Advancement of catheter 40 out of end cap 42 is further facilitated by an outwardly convex surface 44 at the distal end of end cap 42, which includes a plurality of slits 48, preferably four slits 48, as shown in more detail in FIG. 7.

[0075] Thus, the four slits 48 in the end cap 42 may be equally circumferentially spaced apart from one another to essentially form a cross shape, with the slits intersecting or contacting one another at the radial center point of the end cap 42. The slits 48 form four equally shaped flaps 50, which are triangular in shape and connected only on one side of the shape, with free ends at the intersections of the flaps 50. At the intersections, the flaps 50 have truncated regions that may be rounded to provide (small) openings toward the interior cavity 46. This may facilitate proper biasing during closure and opening of the end cap 42, and the initial advancement of the catheter 40 through and out of the end cap 42 may be supported by the small openings, reducing the initial resistance of the flaps 50 due to the resilience of the material.

[0076] The convex shape and multiple slits facilitate the guidance and deployment of the stent 10 and also allow for the use of a smaller bead at the distal end of the guidewire. Furthermore, the end cap 42 can be smaller in size compared to conventional solutions so that the surrounding tissue at the application site is not adversely affected by the end cap 42 and the sizing can be perfectly adapted to that of the stent 10.

[0077] It will be apparent to those skilled in the art that these embodiments and items merely illustrate multiple possible examples. Therefore, the embodiments shown herein should not be understood to form limitations on these features and configurations. Any possible combination and configuration of the described features can be selected in accordance with the scope of the present invention.

[0078] [Explanation of symbols] 10 Stents 12 Main Unit 14 Proximal end region 16 Distal end region 18 aisles 20 1st layer 22 2nd layer 24 Eyelet or first thread section 26 Connection Points 28 Second thread part 30 cannula 32 Wall 34 Inner wall surface 36 Exterior wall 38 Opening 40 Catheter 42 End cap 44 Convex Surface 46 Internal cavity 48 Slit 50 Flap 52 Truncated region [Brief explanation of the drawings]

[0079] [Figure 1] 1 is a schematic diagram of a longitudinal cross section of a stent according to the present invention. [Figure 2] 2 is a reduced schematic view of the stent according to FIG. 1 from the distal end region to the proximal end region. [Figure 3] FIG. 1 is a stretched view of the wall of a stent body having a first layer configuration. [Figure 4] 10 is a stretched view of the wall of a stent body having an alternative first layer configuration. [Figure 5] 2 is a stretched view of the wall of a stent body having the first layer configuration according to FIG. 1. FIG. [Figure 6] 1 is a schematic end cross-sectional view of a catheter having an end cap at its distal end in longitudinal cross-section. FIG. [Figure 7] 7 is a view of the embodiment according to FIG. 6 viewed longitudinally from the distal end.

Claims

1. A stent (10) for introduction into a hollow organ of the human or animal body, preferably into the gastrointestinal tract, in particular into the intestine, comprising: a radially expandable body (12) having a wall (32) defining an internal fluid passageway (18) from one end of the body (12) to an opposite longitudinal end of the body (12); a liquid-tight, flexible first layer (20) covering the surfaces (34, 36) of the wall (32) along the entire periphery and along a first predetermined area longitudinally of the body (12); a resilient, porous second layer (22) covering the outer surface (36) of the wall (32) along its entire periphery and along a second predetermined longitudinal region of the body (12) and at least partially covering the first layer (20); The stent (10) wherein the first layer (20) is disposed on the wall surfaces (34, 36) and extends radially at least partially through the wall (32), and / or the second layer (22) is mechanically fixed to the body (12).

2. The stent (10) of claim 1, wherein the first layer (20) covers an inner surface (34) and an outer surface (36) of the wall (32).

3. 3. The stent (10) of claim 1 or 2, wherein the first predetermined region and / or the second predetermined region correspond to regions of the body (12) having an essentially continuous cross-sectional area.

4. the first predetermined region and / or the second predetermined region are longitudinally defined by at least one end region (14, 16) of the body; A stent (10) according to any one of claims 1 to 3, wherein said at least one end region (14, 16) has an enlarged radial extension.

5. 5. The stent (10) of claim 4, wherein in a longitudinal cross section of the body (12), the at least one end region has a mushroom, dome, toroidal, or donut shape, and / or the body (12) has a barbell shape.

6. 6. The stent (10) of claim 4 or 5, wherein both the first predetermined region and the second predetermined region are defined by both of the opposing end regions (14, 16).

7. 7. The stent (10) of claim 6, wherein the second layer (22) is conformably mechanically secured longitudinally by the opposing end regions (14, 16).

8. The second layer (22) is 8. The stent (10) according to any one of claims 1 to 7, wherein a first thread portion (24) is disposed in the second layer (22) so as to provide at least one small hole (24) on the outer surface of the second layer (22), and a second thread portion (28) is mechanically attached to the main body (12) by at least one thread in adjacent end regions (14, 16) of the main body (12) not covered by the second layer (22), connecting the at least one small hole (24) to a corresponding connection point (26).

9. At least two eyelets (24) are provided by said first thread portion (24), The stent (10) of claim 8, wherein the eyelets (24) are circumferentially spaced apart.

10. 10. The stent (10) of claim 9, wherein the small holes (24) are equally spaced around the circumference and / or 3 to 6 or 4 small holes (24) are provided by the first thread portion (24).

11. 11. A stent (10) according to claim 9 or 10, wherein the second thread portions (28) alternate between adjacent connection points (26) and eyelets (24), and / or each connection point (26) is connected to two adjacent eyelets (24) by the second thread portions (28).

12. A stent (10) according to any one of claims 9 to 11, wherein each connection point (26) is positioned essentially equidistant to two adjacent adjacent eyelets (24).

13. The stent (10) of any one of claims 8 to 12, wherein the first thread portions (24) are disposed within the material of the second layer (22) between adjacent eyelets (24).

14. The stent (10) according to any one of claims 8 to 13, wherein the first thread portion (24) and the second thread portion (28) are formed from a single thread.

15. A stent (10) according to any one of claims 8 to 14, wherein the adjacent end regions (14, 16) are adapted to receive a cannula (30).

16. The stent (10) of any one of claims 1 to 15, further comprising a cannula (30) disposed between the second layer (22) and the first layer (20) and housed essentially outside the body (12).

17. A delivery system for delivering and deploying a stent (10) in a target anatomical region, comprising a catheter (40) having a stent (10) according to any one of claims 1 to 15 in a compressed state.

18. The catheter (40) comprises a distal end cap (42) made of a flexible material; The end cap (42) defines an internal cavity (46) and has a longitudinally convex rounded end surface (44); 18. A delivery system according to claim 17, wherein the end face has at least three, preferably four, circumferentially equally spaced slits (48) from its outer surface towards the internal cavity (46).

19. 20. The delivery system of claim 18, wherein the shape of the end face defined by two circumferentially adjacent slits (48) is truncated at its free end.

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