Stent with dynamic movement prevention properties

Abstract

The medical stent includes a central stent segment, a proximal stent segment adapted to be positioned above the proximal region of the central stent segment, and a distal stent segment adapted to be positioned above the distal region of the central stent segment. A polymer coating extends over the proximal stent segment, the distal stent segment, and at least a portion of the central stent segment, and the polymer coating is adapted to allow the proximal stent segment to float above the proximal region of the central stent segment and the distal stent segment to float above the distal region of the central stent segment. After implantation, the central stent segment is adapted to move parallel to the proximal and distal stent segments in response to peristaltic forces.

Description

Technical Field

[0001] The present disclosure generally relates to methods and devices for various gastrointestinal diseases. More specifically, the present disclosure relates to different configurations of stents as well as methods of manufacture and use.

Background Art

[0002] An implantable stent is a device for being placed within a body structure such as a blood vessel, esophagus, trachea, bile duct, large intestine, intestine, stomach, or body cavity to support the structure and maintain the structure in an open state. These devices are manufactured by any of a variety of different manufacturing methods and can be used according to any of a variety of methods. Each of the known medical devices, delivery systems, and methods has specific advantages and disadvantages. There is a continuing need to provide alternative medical devices and delivery devices, as well as alternative methods for manufacturing and using medical devices and delivery devices.

Summary of the Invention

[0003] The present disclosure relates to alternative designs, materials, and manufacturing methods of medical device structures and assemblies, as well as methods of using them. One example is found in a medical stent. The medical stent includes a central stent segment including a proximal region and a distal region, a proximal stent segment adapted to be disposed over the proximal region of the central stent segment, and a distal stent segment adapted to be disposed over the distal region of the central stent segment. A polymer coating extends over at least a portion of the proximal stent segment, the distal stent segment, and the central stent segment, and the polymer coating is adapted to allow the proximal stent segment to float over the proximal region of the central stent segment and the distal stent segment to float over the distal region of the central stent segment. After implantation, the proximal stent segment and / or the distal stent segment are adapted to translate parallel to the central stent segment in response to peristaltic forces.

[0004] Alternatively, or additionally, the polymer coating may connect the proximal and distal stent segments to the central stent segment and may limit the distance that the proximal and / or distal stent segments can move relative to the central stent segment.

[0005] Alternatively, or additionally, the polymer coating may extend from the proximal end of the central stent segment to the distal end of the central stent segment. Alternatively, or additionally, the proximal stent segment may have an inner diameter greater than the sum of the outer diameter of the central stent segment and twice the thickness of the polymer coating, and the distal stent segment may have an inner diameter greater than the sum of the outer diameter of the central stent segment and twice the thickness of the polymer coating.

[0006] Alternatively, or additionally, the polymer coating may extend over the proximal stent segment, the central portion of the central stent segment, and the distal stent segment. Alternatively, or additionally, at least a portion of the proximal region of the central stent segment is not coated to facilitate drainage.

[0007] Alternatively, or additionally, the proximal stent segment may have an inner diameter larger than the outer diameter of the central stent segment, and the distal stent segment may have an inner diameter larger than the outer diameter of the central stent segment.

[0008] Alternatively, or additionally, the polymer stent segment may include an annular flange. Alternatively or additionally, the distal stent segment may include one or more annular flanges.

[0009] Alternatively or additionally, the central stent segment may include a braided stent segment, the proximal stent segment may include a braided stent segment, and the distal stent segment may include a braided stent segment.

[0010] Another example can be found in a method for forming a medical stent comprising a central stent segment, a proximal stent segment adapted to be positioned above the proximal region of the central stent segment, and a distal stent segment adapted to be positioned above the distal region of the central stent segment. This method includes the step of positioning the proximal stent segment, the central stent segment, and the distal stent segment on a mandrel, with the proximal stent segment positioned at a distance proximal to the proximal end of the central stent segment and the distal stent segment positioned at a distance distal to the distal end of the central stent segment. A polymer coating is formed extending from the proximal stent segment to the distal stent segment, and the polymer coating extends between the proximal stent segment and the proximal end of the central stent segment, and between the distal end of the central stent segment and the distal stent segment to form a stent assembly. The stent assembly is removed from the mandrel. A medical stent is formed by sliding the proximal stent segment onto the proximal region of the central stent segment and sliding the distal stent segment onto the distal region of the central stent segment.

[0011] Alternatively, or additionally, the proximal and distal distances may each be within the range of 10 to 50 percent of the length of the central stent segment. Alternatively, or additionally, the step of forming a polymer coating may include forming a silicone coating.

[0012] Alternatively, or additionally, at least one of the proximal stent segment and the distal stent segment may include an annular flange extending radially outward from the proximal stent segment and / or the distal stent segment.

[0013] Another example can be found in medical stents. A medical stent includes a central stent segment comprising a proximal region, a flared distal region, and a central region interposed between them. The proximal stent segment is fitted to be positioned on top of the proximal region of the central stent segment. A polymer coating extends over the proximal stent segment, the flared distal region of the central stent segment, and the interposing central region. The polymer coating is fitted to fold over itself to position the proximal stent segment on top of the proximal region of the central stent segment.

[0014] Another example can be found in medical stents. A medical stent includes a central stent segment comprising a proximal region and a distal region. The proximal stent segment is fitted to be positioned above the proximal region of the central stent segment. The distal stent segment is fitted to be positioned above the distal region of the central stent segment. A polymer coating extends over the proximal stent segment, the distal stent segment, and at least a portion of the central stent segment, and is fitted to allow the proximal stent segment to float above the proximal region of the central stent segment and the distal stent segment to float above the distal region of the central stent segment. After implantation, the proximal stent segment and / or the distal stent segment are fitted to move parallel to the central stent segment in response to peristaltic forces.

[0015] Alternatively, or additionally, a polymer coating may be used to connect the proximal stent segment to the central stent segment. Alternatively, or additionally, a polymer coating may be used to connect the distal stent segment to the central stent segment.

[0016] Alternatively, or additionally, the polymer coating may limit the distance that the proximal stent segment and / or distal stent segment can move relative to the central stent segment.

[0017] Alternatively, or additionally, the polymer coating may extend from the proximal end of the central stent segment to the distal end of the central stent segment. Alternatively, or additionally, the proximal stent segment may have an inner diameter greater than the sum of the outer diameter of the central stent segment and twice the thickness of the polymer coating, and the distal stent segment may have an inner diameter greater than the sum of the outer diameter of the central stent segment and twice the thickness of the polymer coating.

[0018] Alternatively, or additionally, the polymer coating may extend over the proximal stent segment, the central portion of the central stent segment, and the distal stent segment. Alternatively, or additionally, at least a portion of the proximal region of the central stent segment is not coated to facilitate drainage.

[0019] Alternatively, or additionally, the proximal stent segment may have an inner diameter larger than the outer diameter of the central stent segment, and the distal stent segment may have an inner diameter larger than the outer diameter of the central stent segment.

[0020] Alternatively, or additionally, the polymer stent segment may include an annular flange. Alternatively or additionally, the distal stent segment may include one or more annular flanges.

[0021] Alternatively, or additionally, the central stent segment may include a braided stent segment. Alternatively, or additionally, the proximal stent segment may include a braided stent segment.

[0022] Alternatively, or additionally, the distal stent segment may include a braided stent segment. Another example can be found in a method of forming a medical stent that includes a central stent segment, a proximal stent segment adapted to be disposed over a proximal region of the central stent segment, and a distal stent segment adapted to be disposed over a distal region of the central stent segment. The method includes disposing the proximal stent segment, the central stent segment, and the distal stent segment on a mandrel such that the proximal stent segment is spaced a proximal distance from the proximal end of the central stent segment and the distal stent segment is spaced a distal distance from the distal end of the central stent segment. A polymer coating is formed extending from the proximal stent segment to the distal stent segment, the polymer coating extending between the proximal stent segment and the proximal end of the central stent segment and between the distal end of the central stent segment and the distal stent segment to form a stent assembly. The stent assembly is removed from the mandrel and the proximal stent segment is slid over the proximal region of the central stent segment and the distal stent segment is slid over the distal region of the central stent segment to form the medical stent.

[0023] Alternatively, or additionally, the proximal distance can be in the range of 10 percent to 50 percent of the length of the central stent segment. Alternatively, or additionally, the distal distance can be in the range of 10 percent to 50 percent of the length of the central stent segment.

[0024] Alternatively, or additionally, forming the polymer coating can include forming a silicone coating. Alternatively, or additionally, at least one of the proximal stent segment and the distal stent segment can include an annular flange extending radially outward from the proximal stent segment and / or the distal stent segment.

[0025] Another example can be found in a medical stent. The medical stent includes a central stent segment that includes a proximal region, a flared distal region, and a central region intervening therebetween. The proximal stent segment is adapted to be disposed over the proximal region of the central stent segment. The polymeric coating extends over the proximal stent segment, the flared distal region of the central stent segment, and the intervening central region, and is adapted to be folded back over itself to dispose the proximal stent segment over the proximal region of the central stent segment.

[0026] The foregoing summary is provided to facilitate some understanding of some of the innovative features specific to the present disclosure and is not intended to be a complete description. A complete understanding of the present disclosure can be obtained by considering the entire specification, the claims, the drawings, and the abstract together.

Brief Description of the Drawings

[0027] The present disclosure can be more fully understood by considering the following description of various examples together with the accompanying drawings. [[ID=...]] [Figure 1] It is a schematic diagram of an example of a medical stent. [Figure 2A] It is a schematic diagram showing an exemplary manufacturing process for manufacturing the exemplary medical stent of FIG. 1. [Figure 2B] It is a schematic diagram showing an exemplary manufacturing process for manufacturing the exemplary medical stent of FIG. 1. [[ID=...]] [Figure 2C] It is a schematic diagram showing an exemplary manufacturing process for manufacturing the exemplary medical stent of FIG. 1. [Figure 3A] It is a schematic diagram of an example showing the state where the medical stent of FIG. 1 is implanted in the esophagus. [Figure 3B] It is a schematic diagram of an example showing the state where the medical stent of FIG. 1 is implanted in the esophagus. [Figure 3C] It is a schematic diagram of an example showing the state where the medical stent of FIG. 1 is implanted in the esophagus. [Figure 3D] Note: Some of the tags like [Figure 1] etc. seem to be incomplete in the original text. I've translated as much as possible while keeping them as they are. If there are any specific instructions regarding those incomplete tags, please let me know.Figure 1 is a schematic diagram showing an example of a medical stent implanted in the esophagus. [Figure 4] This is a schematic diagram of an example of a medical stent. [Figure 5] This is a schematic diagram of an example of a medical stent. [Figure 6] This is a schematic diagram of an example of a medical stent. [Modes for carrying out the invention]

[0028] This disclosure may accept various modifications and alternative forms, the details of which are illustrated and described in detail in the drawings. However, it should be understood that the intent is not to limit this disclosure to the specific examples described. Rather, the intent is to encompass all modifications, equivalents, and alternative forms that fall within the spirit and scope of this disclosure.

[0029] The following description should be read with reference to the drawings, where similar elements in different drawings are numbered similarly. The drawings are not necessarily to scale and illustrate examples not intended to limit the scope of this disclosure. While examples are given for various elements, those skilled in the art will recognize that many of the examples provided have suitable alternatives available.

[0030] In this specification, all numbers are considered to be modified by the term “approximately” unless the content clearly indicates otherwise. Numerical ranges indicated by endpoints include all digits contained within that range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0031] Where used herein and in the appended claims, the singular forms “a,” “an,” and “the” include multiple references unless otherwise explicitly indicated herein. Where used herein and in the appended claims, the term “or” is generally adopted in its meaning including “and / or” unless otherwise explicitly indicated herein.

[0032] References in this specification to “one embodiment,” “several embodiments,” and “other embodiments” should be noted to indicate that the embodiments described may include certain features, structures, or characteristics, but not all embodiments necessarily include those features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiments. Moreover, where certain features, structures, or characteristics are described in relation to an embodiment, it is intended that these features, structures, or characteristics may be applicable to other embodiments, whether explicitly described or not, unless the opposite is explicitly stated.

[0033] Stents are used in a variety of different body lumens, including, for example, various parts of the vascular and gastrointestinal systems. In some cases, particularly in gastrointestinal applications, implanted stents may be subjected to a variety of different forces. For example, the gastrointestinal system may consider the stent to be a foreign object to be expelled. In some cases, parts of the gastrointestinal system may try to move the implanted stent distally. In some cases, parts of the gastrointestinal system may try to move the implanted stent proximal, or upward and laterally. It is understood that parts of the gastrointestinal system naturally perform motility (e.g., peristalsis) to cause food and food matter (e.g., partially digested food) to move distally through the gastrointestinal system. Stents placed in various parts of the gastrointestinal system (e.g., the esophagus) are subject to peristalsis. Figure 1 is a schematic diagram of an exemplary medical stent 10 adapted for use in a body lumen where the medical stent 10 is subjected to a variety of motility forces.

[0034] In Figure 1, the exemplary medical stent 10 extends from a proximal end 12 to a distal end 14, but these designations are arbitrary and should be noted as they depend on the orientation in which the medical stent 10 is ultimately implanted in a body lumen. The medical stent 10 includes a central stent segment 16 having a proximal region 18 and a distal region 20. The medical stent 10 includes a proximal stent segment 22 adapted to be positioned on the proximal region 18 of the central stent segment 16. The medical stent 10 includes a distal stent segment 24 adapted to be positioned on the distal region 20 of the central stent segment 16. As shown, the proximal stent segment 22 and the distal stent segment 24 each have an inner diameter larger than the outer diameter of the central stent segment 16. In some examples, the inner diameters of the proximal stent segment 22 and / or distal stent segment 24 may be spaced radially outward from the outer diameter of the central stent segment 16, forming an annular gap between them.

[0035] The central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 are each separate elements that are formed separately and then assembled as a medical stent 10. Therefore, the central stent segment 16 cannot be directly connected to either the proximal stent segment 22 or the distal stent segment 24. Each of the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 may be formed from one or more interwoven filaments. One or more interwoven filaments in each of the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 may not be continuous with one or more interwoven filaments in the other segments. As shown in the figure, each of the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 is formed as a braided stent segment. Various braiding patterns can be used when creating the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24. In some examples, one or more of the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 may be woven stent segments, and in some examples, they may be knitted structures. In some examples, one or more of the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 may be integral tubular structures, such as laser-cut stent segments. In some examples, the central stent segment 16 may be sized to fit into a stenosis in the body lumen where the medical stent 10 is implanted. In some examples, the proximal stent segment 22 and the distal stent segment 24 may each be sized to engage with the lumen wall of the body lumen where the medical stent 10 is implanted.

[0036] The central stent segment 16 may be adapted to move axially (distal and proximal) relative to the proximal stent segment 22 and distal stent segment 24 to accommodate movements such as peristalsis in the body lumen without the medical stent 10 becoming dislodged. In some examples, the central stent segment 16 may be configured such that the proximal stent segment 22 and distal stent segment 24 remain in place relative to the lumen wall of the body lumen in which the medical stent 10 is implanted, while moving in response to applied forces (e.g., axial distal and / or axial proximal). In some examples, the medical stent 10 includes a polymer coating 26 extending over the proximal stent segment 22, distal stent segment 24, and central stent segment 16, thereby connecting the proximal stent segment 22 and distal stent segment 24 with the central stent segment 16. The polymer coating 26 extends between the proximal stent segment 22 and the central stent segment 16, thereby allowing the proximal stent segment 22 to connect with the central stent segment 16. The polymer coating 26 also extends between the distal stent segment 24 and the central stent segment 16, thereby allowing the distal stent segment 24 to connect with the central stent segment 16. In some examples, the polymer coating 26 may be the only structure connecting the central stent segment 16 to the proximal stent segment 22 and / or the distal stent segment 24. In some examples, the polymer coating 26 may be considered to limit the range to which the central stent segment 16 can move parallel to the proximal stent segment 22 and the distal stent segment 24.

[0037] In some examples, the polymer coating 26 may be considered to be configured to allow the proximal stent segment 22 to float over the proximal region 18 of the central stent segment 16 and the distal stent segment 24 to float over the distal region 20 of the central stent segment 16. After implantation, the proximal stent segment 22 and / or distal stent segment 24 may be configured to move in parallel with the central stent segment 16 in response to peristaltic forces, while the central stent segment 16 remains in place relative to the luminal wall of the body lumen in which the medical stent 10 is implanted.

[0038] In some examples, the polymer coating 26 includes a proximal inversion region 28 where the polymer coating 26 is folded over itself to allow the proximal stent segment 22 to be positioned on the proximal region 18 of the central stent segment 16. The proximal inversion region 28 may define the nearest extent of the stent 10, extending proximal to the central stent segment 16 and the proximal stent segment 22. In some examples, the polymer coating 26 includes a distal inversion region 30 where the polymer coating 26 is folded over itself to allow the distal stent segment 24 to be positioned on the distal region 20 of the central stent segment 16. The distal inversion region 30 may define the most distal extent of the stent 10, extending distal to the central stent segment 16 and the distal stent segment 24.

[0039] As further described herein, the central stent segment 16 may be axially movable relative to the proximal stent segment 22 and / or the distal stent segment 24 by shortening the distal inversion region 30 while extending the proximal inversion region 28, and / or by shortening the proximal inversion region 28 while extending the distal inversion region 30. Thus, axial movement of the central stent segment 16 relative to the proximal stent segment 22 and / or the distal stent segment 24 can be achieved without changing the size (e.g., diameter and / or length) of any of the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24.

[0040] Figures 2A to 2C show an exemplary method for forming a medical stent 10. In this example, the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 have already been manufactured and are assembled together to form the medical stent 10. The central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 may be braided, woven, or formed by laser cutting using known techniques. The polymer coating 26 may be applied using known techniques (e.g., spray coating, dipping coating, etc.).

[0041] In Figure 2A, the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 are positioned on a mandrel 34. It will be understood that the mandrel 34 includes a central portion 36 sized to accommodate the central stent segment 16, a first enlarged diameter portion 38 sized to accommodate the proximal stent segment 22, and a second enlarged diameter portion 40 sized to accommodate the distal stent segment 24. The mandrel 34 may include a first tapered portion 42 between the first enlarged diameter portion 38 and the central portion 36. The mandrel 34 may include a second tapered portion 44 between the central portion 36 and the second enlarged diameter portion 40.

[0042] With respect to Figure 2A, several dimensions are shown. The central stent segment 16 has an outer diameter D1. The proximal stent segment 22 has an inner diameter D2. The distal stent segment 24 has an inner diameter D3. Dimensions D1, D2, and D3 vary depending on the overall size of the medical stent 10 and the specific intended implantation site of the medical stent 10. In some examples, the inner diameter D2 of the proximal stent segment 22 and the inner diameter D3 of the distal stent segment 24 may be selected relative to the outer diameter D1 of the central stent segment 16, taking into account the thickness of the polymer coating 26, so that the proximal stent segment 22 and the distal stent segment 24 are positioned above the proximal region 18 and the distal region 20 of the central stent segment 16, respectively. In some examples, the outer diameter D1 of the central stent segment 16 may range from 14 to 25 millimeters for esophageal, intestinal, or obesity treatment applications. For bile duct applications, D1 may range from 5 to 12 millimeters. In some cases, the inner diameter D2 of the proximal stent segment 22 may range from 15 to 35 millimeters. In some cases, such as bile duct applications, D2 may range from 6 to 16 millimeters. As an example, the proximal stent segment 22 may be positioned outside the bile duct and be larger than the bile duct itself. In some cases, the inner diameter D3 of the stent segment 24 may range from 15 to 35 millimeters. The central stent segment 16 is shown as having a constant diameter, but in some cases, the central stent segment 16 may be tapered.

[0043] When positioned on the mandrel 34, the proximal stent segment 22 may be positioned at a distance L1 from the proximal end 46 of the central stent segment 16. When positioned on the mandrel 34, the distal stent segment 24 may be positioned at a distance L2 from the distal end 48 of the central stent segment 16. In some examples, L1 and L2 may be selected to define the relative lengths of the polymer coating 26 that extend across the distance between the proximal stent segment 22 and the central stent segment 16, and between the central stent segment 16 and the distal stent segment 24, respectively. In some examples, the values ​​of L1 and L2 define the lengths of the proximal inversion region 28 and the distal inversion region 30, respectively.

[0044] In some cases, L1 and L2 may affect how much the central stent segment 16 can move parallel to the proximal stent segment 22 and the distal stent segment 24 after implantation. In some cases, L1 and L2 may be chosen to be equal to each other. In some cases, if it is desired to allow relatively large movement between the central stent segment 16 and the proximal stent segment 22, L1 may be chosen to be greater than L2. In some cases, if it is desired to allow relatively large movement between the central stent segment 16 and the distal stent segment 24, L2 may be chosen to be greater than L1. In some cases, L1 and L2 may each be in the range of 10 to 50 percent of the length of the central stent segment 16. In some cases, controlling the lengths of L1 and L2 may be considered as controlling or limiting, for example, the distance that the central stent segment 16 is allowed to slide or move parallel to the proximal stent segment 22 and / or the distal stent segment 24.

[0045] After positioning the central stent segment 16, the proximal stent segment 22, and the distal stent segment 24 on the mandrel 34 with appropriate spacing between the proximal stent segment 22 and the central stent segment 16, and between the central stent segment 16 and the distal stent segment 24, a polymer coating 26 may be applied as shown in Figure 2B. The polymer coating 26 may be applied using known techniques (e.g., spray coating, dipping coating, etc.). As described above, the polymer coating 26 may be applied using any suitable technique such as spray coating or dipping coating. The polymer coating 26 may have a thickness T, as shown in Figure 2B. In some examples, the thickness T may be chosen to create a gap between the inner dimensions of the proximal stent segment 22 and the inner dimensions of the distal stent segment 24, allowing the central stent segment 16 to move in and out of the proximal stent segment 22 and the distal stent segment 24. The thickness T of the polymer coating 26 may be, for example, in the range of 10 microns to 500 microns. In some examples, the thickness T of the polymer coating 26 may be even greater, as long as sufficient clearance is ensured for the central stent segment 16 to move parallel to the proximal stent segment 22 and the distal stent segment 24.

[0046] In some examples, the thickness T is constant over the entire length of the medical stent 10. In some examples, the thickness T of the polymer coating 26 may vary depending on its relative position on the medical stent 10. For example, the polymer coating 26 may be formed thicker in the proximal inversion region 28 and distal inversion region 30 to better withstand the movement of the central stent segment 16 relative to the proximal stent segment 22 and distal stent segment 24 by acting as a living hinge. Alternatively, the polymer coating 26 may be formed thinner in the proximal inversion region 28 and distal inversion region 30 to be more flexible when the central stent segment 16 moves relative to the proximal stent segment 22 and distal stent segment 24.

[0047] As shown in the figure, the polymer coating 26 extends from the proximal end 46 of the central stent segment 16 to the distal end 48 of the central stent segment, covering the entire central stent segment 16. In some examples, the inner diameter D2 of the proximal stent segment 22 is set to be greater than the sum of the outer diameter D1 of the central stent segment 16 and twice the thickness T of the polymer coating 26, so that the proximal stent segment 22 not only fits onto the proximal region 18 of the central stent segment 16 but also allows free movement between the central stent segment 16 and the proximal stent segment 22. Similarly, the inner diameter D3 of the distal stent segment 24 is set to be greater than the sum of the outer diameter D1 of the central stent segment 16 and twice the thickness T of the polymer coating 26, so that the distal stent segment 24 not only fits onto the distal region 20 of the central stent segment 16 but also allows free movement between the central stent segment 16 and the distal stent segment 24.

[0048] Forming a polymer coating 26 on the proximal stent segment 22, the central stent segment 16, and the distal stent segment 24 can be considered as forming the assembly 50. Thus, the polymer coating 26 can connect the proximal stent segment 22, the central stent segment 16, and the distal stent segment 24 to each other to form the assembly 50. The next step is to remove the assembly 50 from the mandrel 34, as shown in Figure 2C. In some examples, the assembly 50 may be flexible enough to be easily pulled out from the mandrel 34. In some examples, the mandrel 34 may be foldable to allow for easier removal of the assembly 50. In some examples, the mandrel 34 may be used in an expanded or inflated form, as shown in Figures 2A and 2B, and removing the assembly 50 from the mandrel 34 simply involves deflating the mandrel 34.

[0049] After the assembly 50 is removed from the mandrel 34, the proximal stent segment 22 moves in the direction indicated by arrow 52, ​​so that the proximal inversion region 28 of the polymer coating 26 is inverted by positioning the proximal stent segment 22 on the proximal region 18 of the central stent segment 16. The distal stent segment 24 moves in the direction indicated by arrow 54, so that the distal stent segment 24 is positioned on the distal region 20 of the central stent segment 16, so that the distal inversion region 30 of the polymer coating 26 is inverted. As a result, a medical stent 10 is obtained, for example, as shown in Figure 1.

[0050] Figures 3A to 3D provide schematic examples illustrating how the medical stent 10 resists peristaltic movement when implanted in the esophagus 56 in close proximity to a narrowing 58 within the esophagus 56. It will be understood that this is merely illustrative, as the medical stent 10 may function similarly in various different body lumens. In Figure 3A, the medical stent 10 can be considered to be in a relaxed state, where no particular force is acting on the proximal stent segment 22 or distal stent segment 24 to cause movement of the central stent segment 16. In this state, the length of the proximal inversion region 28 of the polymer coating 26 is equal to or substantially equal to (within about 10 percent) the length of the distal inversion region 30.

[0051] Moving to Figure 3B, the peristaltic force indicated by arrow 60 attempts to push the proximal stent segment 22 distally. The polymer coating 26 detaches the peristaltic force from the central stent segment 16. As a result of this movement, the proximal inversion region 28 of the polymer coating 26 elongates, while the distal inversion region 30 of the polymer coating 26 shortens or ceases to be inverted. In some examples, as shown in Figure 3C, the polymer coating 26 may elongate in response to the applied force, thereby facilitating the return of the medical stent to a relaxed state when the applied force is removed.

[0052] Moving to Figure 3D, a reverse peristaltic force (which may be caused by one or more of regurgitation or vomiting), indicated by arrow 62, attempts to push the distal stent portion 24 proximal. The polymer coating 26 detaches the peristaltic force from the central stent segment 16. As a result of this movement, the distal inversion region 30 of the polymer coating 26 stretches, while the proximal inversion region 28 of the polymer coating 26 shortens or ceases to be inverted. In some examples, the polymer coating 26 may stretch in response to the applied force, thereby facilitating the return of the medical stent to a relaxed form when the applied force is removed, as shown again in Figure 3C.

[0053] In some cases, it may be sufficient to move only one of the proximal stent segment 22 and distal stent segment 24, rather than both, relative to the central stent region 16. For example, such a configuration may be sufficient in situations where the applied anatomical force that could cause movement is unidirectional, or where a single dynamic element, such as the proximal stent segment 22 and the proximal inversion region 28 of the polymer coating 26, is sufficient to resist the movement. Figure 4 is a schematic diagram of an exemplary medical stent 64 using a proximal stent segment 22 bonded to a central stent segment 66 via a proximal inversion region 28 of the polymer coating 26. The central stent segment 66 includes a flared distal region 68 sized to engage with the luminal wall of the body lumen into which the medical stent 64 is implanted.

[0054] The manufacture of medical stent 64 is similar to that of medical stent 10, and it will be understood that the proximal stent segment 22 is placed on a mandrel at an appropriate distance from the central stent segment 66, a polymer coating 26 is then applied, followed by removal from the mandrel, and the proximal inversion region 28 of the polymer coating 26 is inverted by placing the proximal stent segment 22 on the proximal region 18 of the central stent segment 26. Although illustrated and described as including a proximal stent segment 22 and a distal flared region 68, it will be understood that a medical stent similar to medical stent 64 may instead include a proximal flared region and a distal stent segment 24.

[0055] In some examples, the proximal stent segment 22 and / or distal stent segment 24 may include features intended to improve the stability of the medical stent within an anatomical structure. Figure 5 is a schematic diagram of an exemplary medical stent 70. The medical stent 70 includes a central stent segment 16 extending from a proximal end 46 to a distal end 48, comprising a proximal region 18 and a distal region 20 of the central stent segment 16. The medical stent 70 also includes a proximal stent segment 72 configured to be positioned on the proximal region 18 of the central stent segment 16 and a distal stent segment 74 configured to be positioned on the distal region 20 of the central stent segment 16.

[0056] The manufacture of the medical stent 70 is similar to that of the medical stent 10, in which a proximal stent segment 72, a central stent segment 16, and a distal stent segment 74 are placed on a mandrel with appropriate spacing between them, a polymer coating 26 is then formed, and the stent is removed from the mandrel. Subsequently, the proximal stent segment 72 is placed on the proximal region 18 of the central stent segment 16, thereby forming a proximal inversion region 28, and the distal stent segment 74 is placed on the distal region 20 of the central stent segment 16, thereby forming a distal inversion region 30.

[0057] The proximal stent segment 72 includes an annular flange 76 extending radially outward from the proximal stent segment 72. The distal stent segment 74 comprises a first annular flange 78a and a second annular flange 78b, each of which extends radially outward from the distal stent segment 74. In some examples, the annular flange 76 may be formed integrally when the proximal stent segment 72 is braided, woven, or laser-cut. In some examples, the annular flange 76 may be formed separately and then fixed to the proximal stent segment 72. In some examples, the annular flanges 78a and 78b may be formed integrally when the distal stent segment 74 is braided, woven, or laser-cut. In some examples, the annular flanges 78a and 78b may be formed separately and then fixed to the distal stent segment 74.

[0058] The medical stent 70 is shown having a single annular flange 76 on the proximal stent segment 72 and a pair of annular flanges 78a and 78b on the distal stent segment 74, but this is merely illustrative. In some examples, the proximal stent segment 72 and the distal stent segment 74 may each include a single annular flange. In some examples, the proximal stent segment 72 and the distal stent segment 74 may each include a pair of annular flanges. In some examples, providing a pair of annular flanges on at least one of the proximal stent segment 72 and the distal stent segment 74 may help to orient the medical stent 70 within the body lumen without it being positioned at an angle within the body lumen.

[0059] Figure 6 is a schematic diagram of an exemplary medical stent 80. The exemplary medical stent 80 is similar to medical stent 10, but includes modifications in the way the polymer coating is applied. As seen in Figure 6, the medical stent 80 includes a central stent segment 16 extending from a proximal end 46 to a distal end 48, and comprising a proximal region 18 and a distal region 20 of the central stent segment 16. The central stent segment 16 also includes an intermediate region 82. A proximal stent segment 22 is positioned above the proximal region 18 of the central stent segment 16, and a distal stent segment 24 is positioned above the distal region 20 of the central stent segment 16. The proximal stent segment 22 is positioned radially outward from the central stent segment 16, spaced apart from the central stent segment 16, and may form an annular space between them. Similarly, the distal stent segment 24 may be positioned radially outward from the central stent segment 16, spaced apart from it. The central stent segment 16 may extend within or through the proximal stent segment 22, and / or the central stent segment 16 may extend within or through the distal stent segment 24. In some examples, the central stent segment 16 may extend proximal to the proximal stent segment 22, and / or the central stent segment 16 may extend distal to the distal stent segment 24.

[0060] The medical stent 80 includes a polymer coating 84 extending over a proximal stent segment 22, an intermediate region 82 of the central stent segment 16, and a distal stent segment 24. The polymer coating 84 does not extend to the proximal end 46 or distal end 48 of the central stent segment 16, and therefore does not include an inversion region in a further extent of the stent 80. Rather, the polymer coating 84 includes a proximal hinge region 86 and a distal hinge region 88, which allow the proximal stent segment 22 and the distal stent segment 24 to move axially relative to the central stent segment 16 in response to peristaltic forces. In some examples, one or more ends of the central stent segment 16 may be exposed to facilitate drainage.

[0061] The proximal hinge region 86 of the polymer coating 84 extends between the proximal stent segment 22 and the central stent segment 16, thereby allowing the proximal stent segment 22 to be connected to the central stent segment 16. The distal hinge region 88 of the polymer coating 84 extends between the distal stent segment 24 and the central stent segment 16, thereby allowing the distal stent segment 24 to be connected to the central stent segment 16. In some examples, the polymer coating 84 may be the sole structure connecting the central stent segment 16 to the proximal stent segment 22 and / or the distal stent segment 24. In some examples, the polymer coating 84 may be considered to limit the range to which the central stent segment 16 can be translated relative to the proximal stent segment 22 and the distal stent segment 24.

[0062] In some examples, the inner diameter D2 of the proximal stent segment 22 (see Figure 2A) may be larger than the outer diameter D1 of the central stent segment 16. In some examples, the inner diameter D3 of the distal stent segment 24 may be larger than the outer diameter D1 of the central stent segment 16. In the polymer coating 84 configuration shown in Figure 6, it will be understood that the inner diameter D2 of the polymer stent segment 22 and the inner diameter D3 of the distal stent segment 24 may be smaller than the corresponding diameters shown for the medical stent 10. This is because the medical stent 80 does not need to consider the thickness of the polymer coating 84, since the polymer coating 84 does not extend between the outer surface of the central stent segment 16 and the inner surfaces of the proximal stent segment 22 and the distal stent segment 24. The medical stent 80 is configured to isolate the central stent segment 16 from the applied force.

[0063] The various components of medical stents and mandrels disclosed herein, and the materials that can be used for these various components, may include materials generally associated with medical devices and mandrels. For simplicity of explanation, the following description refers to devices. However, this is not intended to limit the devices and methods described herein, and the description may apply to other elements, members, components, or devices disclosed herein, including but not limited to medical stents, mandrels, filaments, anti-misalignment loops, coverings, and / or their elements or components, etc.

[0064] In some embodiments, the apparatus and / or its components may be made from metals, metal alloys, polymers (some examples of which are shown below), metal-polymer composites, ceramics, combinations thereof, or other suitable materials.

[0065] Some examples of suitable polymers include polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene (ETFE), fluoroethylene 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 copolymers (e.g., butylene / poly(alkylene ether) phthalate and / or other polyester elastomers such as HYTREL® available from DuPont), and polyamides (e.g., DURETHAN® or Elf available from Bayer). Available from Atochem: CRISTAMID®, elastomer polyamides, block polyamides / ethers, polyether block amides (PEBA, e.g., available under trade name PEBAX®), ethylene vinyl 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), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon-12 (EMS American (e.g., GRILAMID® available from Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-β-isobutylene-β-styrene) (e.g., SIBS and / or SIBS)50A) may include polycarbonate, polycarbonate-polyurethane silicone copolymer (e.g., ElastEon® available from Aortech Biomaterials or ChronoSil® available from AdvanSource Biomaterials), biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers, polymer / metal composites, and the like. In some embodiments, the sheath may be formulated with liquid crystal polymer (LCP). For example, the mixture may contain up to about 6 percent LCP.

[0066] Some examples of suitable metals and metal alloys include stainless steel such as 304V stainless steel, 304L stainless steel, and 316LV stainless steel, mild steel, nickel-titanium alloys such as linear elastic and / or superelastic Nitinol, and nickel-chromium-molybdenum alloys (e.g., UNS:N06625 such as INCONEL® 625, UNS:N06022 such as HASTELLOY® C-22®, UNS:N10 such as HASTELLOY® C276®). 276, other nickel alloys such as other HASTELLOY® alloys and similar ones, nickel-copper alloys (e.g., UNS:N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, and similar ones), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035 such as MP35-N® and similar ones), nickel-molybdenum alloys (e.g., HASTELLOY® ALLOY This includes UNS:N10665, such as B2 (trademark), 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, and similar materials, cobalt-chromium alloys, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY®, PHYNOX®, and similar materials), platinum-enriched stainless steel, titanium, platinum, palladium, gold, combinations thereof, or any other suitable material.

[0067] In at least some embodiments, some or all of the apparatus and / or components may also be doped with, fabricated from, or contain radiopaque materials. Radiopaque materials are understood to be materials that can produce relatively bright images on a fluoroscopic screen or with other imaging techniques during medical procedures. These relatively bright images assist the user of the apparatus in determining their location. Some examples of radiopaque materials include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, and polymer materials loaded with radiopaque fillers. Furthermore, other radiopaque marker bands and / or coils may be incorporated into the design of the apparatus to achieve the same result.

[0068] In some embodiments, a certain degree of magnetic resonance imaging (MRI) compatibility is imparted to the apparatus and / or other elements disclosed herein. For example, the apparatus and / or its components or parts may be made of materials that do not substantially distort the image and do not produce substantial artifacts (e.g., gaps in the image). For example, certain ferromagnetic materials may be unsuitable because they can produce artifacts in MRI images. The apparatus or parts thereof may also be made of materials that the MRI equipment can image. Some materials exhibiting these properties include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003 such as ELGILOY® and PHYNOX®), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035 such as MP35-N®), nitinol, and others.

[0069] In some embodiments, the apparatus and / or other elements disclosed herein may include and / or be treated with a suitable therapeutic agent. Some examples of suitable therapeutic agents include antithrombotic agents (heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethyl ketone), etc.); proliferation inhibitors (enoxaparin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid, etc.); anti-inflammatory agents (dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine, etc.); antitumor / antiproliferative / antimitotic agents (paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothirone, endostatin, angiostatin, and thymidine kinase inhibitors, etc.); anesthetic agents (lidocaine, bupivacaine, Examples include: anticoagulants (such as ropivacaine); anticoagulants (such as D-Phe-Pro-Arg chloromethyl ketone, RGD peptide-containing compounds, heparin, antithrombin compounds, platelet receptor antagonists, antithrombin antibodies, antiplatelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors, and mite antiplatelet peptides); vasodilators (such as growth factor inhibitors, growth factor receptor antagonists, transcription activators, and translation promoters); vasodilators (such as growth factor inhibitors, growth factor receptor antagonists, transcription inhibitors, translation inhibitors, replication inhibitors, inhibitory antibodies, antibodies against growth factors, bifunctional molecules consisting of growth factors and cytotoxins, bifunctional molecules consisting of antibodies and cytotoxins); cholesterol-lowering agents; vasodilators; and agents that interfere with intrinsic vasoactive mechanisms.

[0070] While several embodiments of the present disclosure have been described above, those skilled in the art will readily understand that further embodiments can be constructed and used within the scope of the appended claims. However, it should be understood that the present disclosure is in many respects merely illustrative. Detailed modifications are possible, particularly in terms of shape, size, arrangement of parts, and exclusion or sequence of steps, without exceeding the scope of the present disclosure. The scope of the present disclosure is, of course, defined by the language expressed in the appended claims.

Claims

1. It is a medical stent, A central stent segment including the proximal and distal regions, A proximal stent segment adapted to be positioned above the proximal region of the central stent segment, A distal stent segment adapted to be positioned above the distal region of the central stent segment, A polymer coating extending over at least a portion of the proximal stent segment, the distal stent segment, and the central stent segment, wherein the polymer coating is adapted to allow the proximal stent segment to float over the proximal region of the central stent segment and the distal stent segment to float over the distal region of the central stent segment, A medical stent in which, after implantation, the proximal stent segment and / or the distal stent segment are adapted to move parallel to the central stent segment in response to peristaltic forces.

2. The medical stent according to claim 1, wherein the polymer coating connects the proximal stent segment and the distal stent segment to the central stent segment, and limits the distance that the proximal stent segment and / or the distal stent segment can move relative to the central stent segment.

3. The medical stent according to claim 1 or 2, wherein the polymer coating extends from the proximal end of the central stent segment to the distal end of the central stent segment.

4. The proximal stent segment has an inner diameter larger than the sum of the outer diameter of the central stent segment and twice the thickness of the polymer coating. The medical stent according to any one of claims 1 to 3, wherein the distal stent segment has an inner diameter greater than the sum of the outer diameter of the central stent segment and twice the thickness of the polymer coating.

5. The medical stent according to claim 1 or 2, wherein the polymer coating extends over the proximal stent segment, the central portion of the central stent segment, and the distal stent segment.

6. The medical stent according to claim 5, wherein at least a portion of the proximal region of the central stent segment is not coated to facilitate drainage.

7. The proximal stent segment has an inner diameter larger than the outer diameter of the central stent segment. The medical stent according to claim 5 or 6, wherein the distal stent segment has an inner diameter larger than the outer diameter of the central stent segment.

8. The medical stent according to any one of claims 1 to 7, wherein the polymer stent segment includes an annular flange.

9. The medical stent according to any one of claims 1 to 8, wherein the distal stent segment includes one or more annular flanges.

10. The aforementioned central stent segment includes a braided stent segment, The aforementioned proximal stent segment includes a braided stent segment. The distal stent segment includes a braided stent segment, as described in any one of claims 1 to 9.

11. A method for forming a medical stent comprising a central stent segment, a proximal stent segment adapted to be positioned on the proximal region of the central stent segment, and a distal stent segment adapted to be positioned on the distal region of the central stent segment, The steps include: positioning the proximal stent segment, the central stent segment, and the distal stent segment on a mandrel, with the proximal stent segment positioned at a distance proximal to the proximal end of the central stent segment, and the distal stent segment positioned at a distance distal to the distal end of the central stent segment; A step of forming a polymer coating extending from the proximal stent segment to the distal stent segment, wherein the polymer coating extends between the proximal stent segment and the proximal end of the central stent segment, and between the distal end of the central stent segment and the distal stent segment to form a stent assembly; The steps include removing the stent assembly from the mandrel, A method comprising the steps of sliding the proximal stent segment onto the proximal region of the central stent segment and sliding the distal stent segment onto the distal region of the central stent segment to form the medical stent.

12. The method according to claim 11, wherein the proximal distance and the distal distance are each within the range of 10 to 50 percent of the length of the central stent segment.

13. The method according to claim 11 or 12, wherein the step of forming the polymer coating includes forming a silicone coating.

14. The method according to any one of claims 11 to 13, wherein at least one of the proximal stent segment and the distal stent segment includes an annular flange extending radially outward from the proximal stent segment and / or the distal stent segment.

15. It is a medical stent, A central stent segment including a proximal region, a flared distal region, and a central region interposed between them, A proximal stent segment adapted to be positioned on the proximal region of the central stent segment, The stent comprises a polymer coating extending over the proximal stent segment, the flared distal region of the central stent segment, and the intervening central region. A medical stent in which the polymer coating is adapted to fold over itself to position the proximal stent segment on the proximal region of the central stent segment.

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