Medical device
The stent with structurally stable tubular members and outwardly extending posts addresses migration issues by securing within the lumen, providing stable anchoring and flexibility, thus preventing complications.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ALLIUM
- Filing Date
- 2025-12-17
- Publication Date
- 2026-06-25
AI Technical Summary
Ureteral stents often migrate within the body, leading to complications such as pain, bleeding, and infection, necessitating complex retrieval procedures.
A stent with structurally stable tubular members and radially outwardly extending posts that provide anchoring arrangements, ensuring secure placement and flexibility to conform to bodily lumens, while maintaining a throughgoing passage without external support.
The stent effectively prevents migration, ensuring stable positioning and reducing complications by securely anchoring within the lumen, allowing for flexible conformation to bodily structures and maintaining patency.
Smart Images
Figure IL2025051122_25062026_PF_FP_ABST
Abstract
Description
[0001] MEDICAL DEVICE
[0002] TECHNOLOGICAL FIELD
[0003] The presently disclosed subject matter relates to medical devices, and in particular to stents configured to be inserted into a bodily lumen to maintain an open passageway therethrough.
[0004] BACKGROUND
[0005] Stents are a common way of holding open passages in the body, such as blood vessels, ducts, etc., in order to maintain flow of fluid therethrough. Ureteral stents are implanted in the ureter, allowing urine to flow and prevent blockages, for example from kidney stones, tumors, or other similar growths.
[0006] In order to ensure proper functioning of a stent, it is necessary to prevent it from moving within the passage once implanted. In the case of uterine stents, migration toward either the bladder or the kidney may result in complications such as localized pain, frequency and / or burning sensations with urination, blood in the urine, infection, etc. In such a case, the stent must be retrieved, often requiring a complex procedure.
[0007] SUMMARY
[0008] According to an aspect of the presently disclosed subject matter there is provided a medical device comprising: a stent comprising a structurally stable tubular member bounded by an exterior surface of the stent, the tubular member defining a throughgoing longitudinal passage; and one or more anchoring arrangements configured to facilitate securing the medical device at a location within a bodily lumen; each of the anchoring arrangements comprising a plurality of posts extending radially outwardly from the exterior surface of the stent, each of the posts being substantially the same height as posts adjacent thereto, wherein the center-to-center distance between adjacent posts is optionally substantially 1.6 times the height of the post.
[0009] Herein the specification and appended claims, descriptions / recitations of the stent / tubular member being structurally stable indicate that it is configured to maintain, without external support, its generally tubular structure as required to function to provide luminal patency, nor are any constraints necessary for it to maintain its generally tubular structure. In this context, being structurally stable does not preclude having flexibility which may be necessary to conform to the shape of the bodily lumen.
[0010] Herein the specification and appended claims, descriptions / recitations of the posts extending from the exterior surface which bounds the structurally stable tubular member, indicate that the exterior surface is necessary for the structural stability of the stent, i.e., the posts are formed such that they extent from a portion of the stent which is a necessary element of a structurally stable tubular member, and not, e.g., from an exterior coating layer which is provided solely for a non- structural purpose, such as to introduce a therapeutic agent.
[0011] The posts may be monolithically formed with the exterior surface of the stent.
[0012] The stent may comprise a flexibly rigid frame enveloped within a flexible sheath.
[0013] The length of the gap between adjacent posts may be between about 0.45 and about 0.75 times the height of each of the adjacent posts. The length of the gap between adjacent posts may be about 0.6 times the height of each of the adjacent posts.
[0014] The posts may be elastically flexible.
[0015] The medical device may comprise a plurality of anchoring arrangements, wherein the smallest distance between posts of different anchoring arrangements is at least three times the center-to-center distance between posts of the same anchoring arrangement.
[0016] The height of each of the posts may be no greater than about 45 pm. The height of each of the posts may be not less than about 35 pm. The average height of the posts may be about 40 pm.
[0017] The posts may be substantially the same height.
[0018] Each of the posts may have a substantially constant radial cross-section (i.e., taken along a plane which coincides with the radial direction of the post, wherein the cutting plane is perpendicular to the longitudinal axis of the post) along a majority of its height, for example having a substantially cylindrical shape along a majority of its height.
[0019] A distal surface of each of the posts may be blunt.
[0020] At least one of the anchoring arrangements may define a longitudinally extending fluid path spanning the length of the stent. The longitudinally extending fluid path may comprise a generally helical path about the longitudinal axis of the stent. The bodily lumen may be a portion of the urinary system, for example comprising the ureter, the prostatic urethra, the bulbar urethra, the bladder neck, or an anastomosis between the bladder neck and the membranous urethra. The bodily lumen may be a bile duct.
[0021] BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
[0023] Fig. 1A is a perspective view of a medical device according to the presently disclosed subject matter;
[0024] Fig. IB is a cross-sectional view of the medical device taken along line I-I in Fig. 1A;
[0025] Figs. 2A through 2D are perspective views illustrating examples of anchoring arrangements of the medical device illustrated in Fig. 1 A;
[0026] Fig- 3 is a schematic closeup side view of an anchoring arrangement of the medical device illustrated in Fig. 1 A in use; and
[0027] Figs. 4A through 4D are schematic side views of examples of the medical device illustrated in Fig. 1 A.
[0028] DETAILED DESCRIPTION OF EMBODIMENTS
[0029] As illustrated in Figs. 1A and IB, there is provided a medical device, which is generally indicated at 10, configured to be secured within a bodily lumen to maintain and / or provide a throughgoing passage therethrough. The bodily lumen may be, e.g., a bile duct, a portion of the urinary system such as the ureter, the prostatic urethra, the bulbar urethra, the bladder neck, or an anastomosis between the bladder neck and the membranous urethra, etc.
[0030] The medical device 10 comprises a stent 12, formed as a longitudinally extending tubular member, having an exterior surface 14 and an interior surface 16. The interior surface 16 defines a hollow longitudinally interior passage 18 passing therethrough from a first end 20a of the stent 12 to a second end 20b of the stent. The medical device 10 may be configured for use in a specific bodily lumen, and the dimensions thereof and of its elements, choice of materials, etc., may be chosen accordingly, for example as is well known in the art.
[0031] In the present disclosure, different elements indicated by a single reference numeral and distinguished by their trailing letters may be collectively indicated using the single reference numeral without a trailing letter, e.g., reference numeral 20 may be used to collectively indicate first and second ends 20a and 20b.
[0032] The stent 12 may comprise a flexibly rigid frame 22 enveloped in a flexible sheath 24. The frame 22 may provide sufficient radial rigidity to facilitate maintaining the passage 18 in an open position while exhibiting sufficient flexibility to be radially contracted and expanded for implantation, to bend to the shape of and with movement of the bodily lumen, etc. It may be made of any suitable material for example as is known in the art, including, but not limited to, stainless steel, one or more cobalt-chromium alloys, one or more nickel -titanium alloys (e.g., nitinol), platinum, one or more tantalum alloys, and / or titanium. The frame 22 may comprise a mesh structure for example as illustrated, and / or be over any another suitable design.
[0033] The sheath 24 may be made of any suitable material, for example a polymer, e.g., comprising one or more silicone and / or polyurethane polymers.
[0034] As illustrated in Figs. 2A through 2D, the exterior surface 14 of the stent 12 is formed with one or more anchoring arrangements 26, configured to grip the interior wall of the bodily lumen, thereby facilitating securing the medical device 10 thereto, and arresting its position within the lumen.
[0035] Each of the anchoring arrangements 26 comprises a plurality of longitudinal posts 28 (i.e., the posts extend longitudinally along their own axes) extending radially outwardly from the exterior surface 14 of the stent 12. The posts 28 may be formed monolithically with the exterior surface 14 of the stent 12. The posts may be elastically flexible, for example exhibiting a tendency to be biased toward their vertical positions (indicated at 28a in Fig. 3) when experiencing a lateral force F, i.e., which is lateral with respect to the longitudinal axes of the posts), thereby allowing them to move laterally to accommodate the tissue of the bodily lumen, while biasing them toward their vertical rest positions to facilitate gripping of the tissue.
[0036] According to examples in which the exterior surface 14 is formed with a plurality of anchoring arrangements 26, each may be spaced from each other, i.e., considering the minimum distance between separate anchoring arrangements, by a distance which is larger than the distance between adjacent posts 28 thereof, for example as described below.
[0037] The posts 28 may be of any suitable shape. According to some examples, the posts 28 have a generally cylindrical shape, i.e., each having a circular cross-section wherein the cutting plane is perpendicular to its own longitudinal axis. Distal surfaces 30 of the posts 28 may be blunt, i.e., free of sharp or pointed features which may present a nontrivial risk of cutting, piercing, etc., the biological lumen when the medical device 10 is secured therewithin.
[0038] According to some examples, the height h of each of the posts 28 is between about 35 pm and about 45 pm. According to some examples, the height h of each of the posts 28 is about 40 pm.
[0039] According to some examples, the diameter d of each of the posts 28 is between about 35 pm and about 45 pm. According to some examples, the diameter d of each of the posts 28 is about 40 pm. According to examples wherein the posts 28 have a noncircular cross-section, the diameter d may be considered as the largest diameter, the mean value of the diameter, or the average of the largest and smallest values of the diameter.
[0040] The posts 28 may be substantially short. For example, the ratio of the height h to the diameter d of each post 28 may be less than about 1.2, optionally between about 0.8 and 1.2. According to some examples, the ratio of the height h to the diameter d of each post 28 may be about 1.
[0041] The posts 28 may be substantially the same height, i.e., their longitudinal axes extend the same radial distance from the exterior surface 14 as do posts adjacent thereto. According to some examples, all of the posts 28 in the same anchoring arrangement 26 may be substantially the same height. According to some examples, all of the posts 28 on the medical device 10 are substantially the same height.
[0042] The posts 28 may be in any suitable arrangement. According to some examples, the posts 28 may be arranged in a rectangular or square grid such as is illustrated in Fig. 2A, i.e., wherein each non-edge posts are adjacent to four other posts which are disposed at angles to each other (i.e., when considering center-to-center lines of the posts) which are multiples of 90°. While the example illustrated in Fig. 2A comprises a limited number of posts 28, this is illustrative of a general grid pattern, and is not to be construed as limiting. In practice, an anchoring arrangement 26 comprising posts 28 arranged in a grid may comprise more or fewer posts than as illustrated in Fig. 2A without departing from the scope of the presently disclosed subject matter, mutatis mutandis.
[0043] According to some examples, the posts 28 may be arranged in a honeycomb pattern such as is illustrated in Figs. 2B through 2D. Herein the specification and appended claims, the term “honeycomb pattern” refers to an arrangement wherein all posts 28 adjacent to a given post are disposed at angles to each other which are multiples of 60°. While some posts 28 in such an arrangement may be adjacent to six other posts, others, e.g., those at the edge, may be adjacent to fewer posts 28. It will be appreciated that a honeycomb pattern maximizes the number of pairs of adjacent posts 28.
[0044] As illustrated in Figs. 2B and 2C, one or more of the anchoring arrangements 26 may comprise a plurality of posts 28 arranged in a honeycomb pattern with no missing posts, i.e., no additional posts could be added within the anchoring arrangement without deviating from the honeycomb pattern as described above. While the examples illustrated in Figs. 2B and 2C comprise a limited number of posts 28, this is illustrative of a general honeycomb pattern, and is not to be construed as limiting. In practice, an anchoring arrangement 26 comprising posts 28 arranged in a honeycomb pattern may comprise more or fewer posts than as illustrated in Figs. 2B or 2C without departing from the scope of the presently disclosed subject matter, mutatis mutandis.
[0045] As illustrated in Fig. 2D, one or more of the anchoring arrangements 26 may comprise a plurality of posts 28 arranged in a plurality of honeycomb groups, indicated by 32, each having a honeycomb pattern, e.g., arranged as a hexagonal formation, for example as described above with reference to and illustrated in Fig. 2B, and each being adjacent other such honeycomb groups 32 leaving a gap 34 therebetween. According to some examples, a honeycomb groups 32 may comprise a single post, indicated atH, which is adjacent a corresponding post B in an adjacent honeycomb group. The distance between the closest posts 28 of adjacent honeycomb groups 32 may be the same as the distance between adjacent posts within the same honeycomb group, for example as described below. While the example illustrated in Fig. 2D comprises a limited number of posts, this is illustrative of a general honeycomb pattern, and is not to be construed as limiting. In practice, an anchoring arrangement 26 comprising posts 28 arranged in a plurality of honeycomb groups 32 may comprise more or fewer posts than as illustrated in Fig. 2D, without departing from the scope of the presently disclosed subject matter, mutatis mutandis. Moreover, the honeycomb groups 32 may be larger than illustrated, e.g., forming a larger hexagon than illustrated, and / or the anchoring arrangement 26 may comprise more honeycomb groups.
[0046] It will be appreciated that while Figs. 2A through 2D and their accompanying descriptions disclose typical examples of anchoring arrangements 26, these are by way of example only and are not to be construed as limiting. Moreover, some or all of the anchoring arrangements 26 may comprise a plurality of different patterns, i.e., some of the posts 28 thereof are arranged according to one pattern, while others are arranged according to another pattern, mutatis mutandis. In addition, the exterior surface 14 of the stent 12 may be formed with a plurality of anchoring arrangements 26, some of which comprise different patterns than do other anchoring arrangements.
[0047] According to some examples, the posts 28 may be arranged such that the center- to-center distance c between adjacent posts is substantially 1.6 times the height h of the posts (see Fig. 2B). According to some examples, the posts 28 may be arranged such that the length of gap g, i.e., the smallest distance, between adjacent posts is between about 0.45 times the height h of the posts and about 0.75 times the height h of the posts, for example about 0.6 times the height h of the posts. It has been found that this configuration facilitates a secure grip between the exterior surface 14 of the stent 12 and the corresponding area of the interior surface of the bodily lumen.
[0048] It has been further found that this configuration may facilitate gripping the interior surface of the bodily lumen without the tissue of the bodily lumen being fully received within the space between the posts 28, for example as illustrated in Fig. 3. Accordingly, areas 34 between the posts 28, in particular adjacent the proximal ends thereof, may be free of material of the medical device 10 and of tissue, thereby providing a passageway for fluid to flow therethrough. Accordingly, one or more anchoring arrangements 26 may be provided spanning the length of the stent 12 between the first and second ends 20a, 20b thereof, thereby defining an axially extending fluid path exterior to the stent.
[0049] As illustrated in Fig. 4A, the medical device 10 may comprise a single anchoring arrangement 26 formed on the exterior surface 14 along a generally helical path about the longitudinal axis of the stent 12. Such a path may define an axially extending fluid path exterior to the stent 12, as described above. The helical path be formed having any suitable width, lead angle 2, etc., for example to facilitate efficient fluid flow therethrough. According to some examples, the lead angle 2 may be between about 7° and about 14°; e.g., a stent 12 having a diameter of 10 mm may be formed with a helical anchoring arrangement 26 having a pitch p between about 4 mm and about 8 mm, for example having a pitch p of about 6 mm.
[0050] As illustrated in Figs. 4B and 4C, the medical device 10 may comprise one or more anchoring arrangements 26 formed as circumferential rings on the exterior surface 14 of the stent 12. According to some examples, the medical device 10 may comprise one or more of such anchoring arrangements 26, near one or both of the ends 20, for example as illustrated in Fig. 4B. According to some examples, the medical device 10 may comprise a plurality of such anchoring arrangements 26 axially spaced from each other along most or all of the length of the stent 12, for example as illustrated in Fig. 4C.
[0051] As illustrated in Fig. 4D, the medical device may comprise one or more anchoring arrangements 26 formed as patches.
[0052] Herein the specification and appended claims, descriptions of a post being adjacent to one or more other posts refers to the other posts being no farther from the post than are any other post.
[0053] It will be recognized that examples, embodiments, modifications, options, etc., described herein are to be construed as inclusive and non-limiting, i.e., two or more examples, etc., described separately herein are not to be construed as being mutually exclusive of one another or in any other way limiting, unless such is explicitly stated and / or is otherwise clear. Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations, and modifications can be made without departing from the scope of the presently disclosed subject matter, mutatis mutandis.
Claims
CLAIMS:
1. A medical device comprising: a stent comprising a structurally stable tubular member bounded by an exterior surface of the stent, the tubular member defining a throughgoing longitudinal passage; and one or more anchoring arrangements configured to facilitate securing the medical device at a location within a bodily lumen; each of the anchoring arrangements comprising a plurality of posts extending radially outwardly from the exterior surface of the stent, each of the posts being substantially the same height as posts adjacent thereto, wherein the center-to-center distance between adjacent posts is substantially 1.6 times the height of the post.
2. The medical device according to claim 1, wherein the posts are monolithically formed with the exterior surface of the stent.
3. The medical device according to any one of the preceding claims, wherein the stent comprises a flexibly rigid frame enveloped within a flexible sheath.
4. The medical device according to any one of the preceding claims, wherein the length of the gap between adjacent posts is between about 0.45 and about 0.75 times the height of each of the adjacent posts.
5. The medical device according to claim 4, wherein the length of the gap between adjacent posts is about 0.6 times the height of each of the adjacent posts.
6. The medical device according to any one of the preceding claims, wherein the posts are elastically flexible.
7. The medical device according to any one of the preceding claims, comprising a plurality of anchoring arrangements, wherein the smallest distance between posts of different anchoring arrangements is at least three times the center-to-center distance between posts of the same anchoring arrangement.
8. The medical device according to any one of the preceding claims, wherein the height of each of the posts is not greater than about 45 pm.
9. The medical device according to any one of the preceding claims, wherein the height of each of the posts is not less than about 35 pm.
10. The medical device according to any one of the preceding claims, wherein the average height of the posts is about 40 pm.
11. The medical device according to any one of the preceding claims, wherein the posts are substantially the same height.
12. The medical device according to any one of the preceding claims, wherein each of the posts has a substantially constant radial cross-section along a majority of its height.
13. The medical device according to claim 12, wherein each of the posts has a substantially cylindrical shape along a majority of its height.
14. The medical device according to any one of the preceding claims, wherein a distal surface of each of the posts is blunt.
15. The medical device according to any one of the preceding claims, wherein at least one of the anchoring arrangements defines a longitudinally extending fluid path spanning the length of the stent.
16. The medical device according to claim 15, wherein the longitudinally extending fluid path comprises a generally helical path about the longitudinal axis of the stent.
17. The medical device according to any one of the preceding claims, wherein the bodily lumen is a portion of the urinary system or a bile duct.
18. The medical device according to claim 17, wherein the portion of the urinary system comprises the ureter, the prostatic urethra, the bulbar urethra, the bladder neck, or an anastomosis between the bladder neck and the membranous urethra.