ANEURYSM OCCLUSION DEVICE, THERAPEUTIC APPARATUS FOR ANEURYSM OCCLUSION AND ANEURYSM OCCLUSION SYSTEM

Abstract

An aneurysm occlusion device (10), a therapeutic apparatus for aneurysm occlusion and an aneurysm occlusion system. The aneurysm occlusion device (10) includes an expandable mesh structure (11) and a guide structure (12). The expandable mesh structure (11) has an expanded configuration, in which it assumes a spiral shape spiraling from a distal end (111) to a proximal end (112) thereof, and a collapsed configuration for its delivery into an aneurysm (30) from a blood vessel. At least a portion of the guide structure (12) is disposed in an inner cavity defined by the expandable mesh structure (11) and, when the expandable mesh structure (11) is in the spiral shape, expands into a spiral shape in the inner cavity of the expandable mesh structure (11). The aneurysm occlusion device (10) provides the advantages of, among others, stably and compliantly packing the aneurysm (30) while avoiding its rupture, preventing vascular embolism, improving coverage of an opening at the neck of the aneurysm, promoting thrombosis in the aneurysm (30) and accelerating embolization of the aneurysm (30).

Claims

1. An aneurysm occlusion device, comprising: an expandable mesh structure having an expanded configuration, in which the expandable mesh structure forms a spiral shape by spiraling from a distal end to a proximal end thereof, and a collapsed configuration for delivery into an aneurysm from a blood vessel; and a guide structure, at least a portion of which is disposed in an inner cavity defined by the expandable mesh structure and, when the expandable mesh structure is in the spiral shape, expands into a spiral shape in the inner cavity of the expandable mesh structure.

2. The aneurysm occlusion device according to claim 1, wherein the spiral shape of the expandable mesh structure in the expanded configuration thereof is a three-dimensional spiral shape formed by spiraling from the distal end to the proximal end; or wherein the guide structure is at least partially made of a radiopaque material.

3. (canceled)

4. The aneurysm occlusion device according to claim 1, wherein the guide structure has a first section that is disposed in the inner cavity of the expandable mesh structure and a second section that extends out of the expandable mesh structure from the distal end thereof.

5. The aneurysm occlusion device according to claim 4, wherein the second section of the guide structure that extends out of the expandable mesh structure from the distal end thereof has a spiral shape when in the expanded configuration; or wherein the second section of the guide structure that extends out of the expandable mesh structure from the distal end thereof has a three-dimensional spiral shape.

6. (canceled)

7. The aneurysm occlusion device according to claim 1, wherein the guide structure has a linear structure.

8. The aneurysm occlusion device according to claim 1, wherein both the proximal and distal ends of the expandable mesh structure are fixedly connected to the guide structure, and an axial length of a first section of the guide structure that is disposed in the inner cavity of the expandable mesh structure in the expanded configuration is not smaller than an axial length of the expandable mesh structure in the collapsed configuration.

9. The aneurysm occlusion device according to claim 1, wherein a distal radiopaque ring is fixedly connected to the distal end of the expandable mesh structure, and/or a proximal radiopaque ring is fixedly connected to the proximal end of the expandable mesh structure.

10. The aneurysm occlusion device according to claim 1, wherein a cross-sectional area of the expandable mesh structure increases and then decreases from the proximal end to the distal end.

11. The aneurysm occlusion device according to claim 10, wherein the expandable mesh structure comprises a proximal section, a middle section and a distal section which are connected axially in sequence, wherein a cross-sectional area of the proximal section gradually increases from a proximal end to a distal end thereof, and/or a cross-sectional area of the distal section gradually increases from a distal end to a proximal end thereof.

12. The aneurysm occlusion device according to claim 10, wherein the cross-sectional area of the expandable mesh structure repeatedly increases and decreases from the proximal end to the distal end.

13. The aneurysm occlusion device according to claim 1, wherein in the expanded configuration, a maximum outer diameter of the expandable mesh structure is not smaller than ¼ of an outer diameter of a largest spiral turn in the expandable mesh structure; or wherein in the expanded configuration, a maximum outer diameter of the expandable mesh structure is ⅓ to ½ of the outer diameter of the largest spiral turn in the expandable mesh structure.

14. (canceled)

15. The aneurysm occlusion device according to claim 1, wherein the expandable mesh structure is formed by braiding filaments made of a material comprising a shape memory material.

16. The aneurysm occlusion device according to claim 15, wherein the expandable mesh structure is formed by braiding 48-144 filaments having an outer diameter of 0.0005-0.002 inches; or wherein the expandable mesh structure is formed by braiding radiopaque filaments, or the expandable mesh structure is formed by braiding both radiopaque and non-radiopaque filaments.

17. (canceled)

18. The aneurysm occlusion device according to claim 1, wherein the spiral shape of the expandable mesh structure in the expanded configuration has one spiral turn or a plurality of spiral turns, wherein in case of the plurality of spiral turns, a first one of the spiral turns in the expandable mesh structure proximal to the distal end thereof has an outer diameter smaller than an outer diameter of each middle one of the spiral turns.

19. The aneurysm occlusion device according to claim 18, wherein in case of the plurality of spiral turns, a last one of the spiral turns in the expandable mesh structure proximal to the proximal end thereof has an outer diameter smaller than the outer diameter of each middle spiral turn; wherein in the spiral shape of the expandable mesh structure in the expanded configuration, the outer diameter of the first spiral turn proximal to the distal end is equal to the outer diameter of the last spiral turn proximal to the proximal end; wherein in the spiral shape of the expandable mesh structure in the expanded configuration, the outer diameter of the first spiral turn proximal to the distal end is ⅔ of the outer diameter of each middle spiral turn.

20. (canceled)

21. (canceled)

22. The aneurysm occlusion device according claim 5, wherein the spiral shape of the second section of the guide structure that extends out of the expandable mesh structure from the distal end thereof in the expanded configuration has one spiral turn or a plurality of spiral turns, wherein in case of the plurality of spiral turns, a first one of the spiral turns in the guide structure proximal to an distal end thereof has an outer diameter smaller than an outer diameter of each spiral turn other than the first spiral turn.

23. The aneurysm occlusion device according to claim 22, wherein in case of the spiral shape of the second section of the guide structure that extends out of the expandable mesh structure from the distal end thereof in the expanded configuration having the plurality of spiral turns, the outer diameter of each spiral turn in the guide structure does not exceed an outer diameter of a first spiral turn in the expandable mesh structure proximal to the distal end thereof; wherein the outer diameter of the first spiral turn in the guide structure proximal to the distal end thereof is ⅔-¾ of the outer diameter(s) of the other spiral turn(s), which is/are equal and not smaller than ⅔ of an outer diameter of a first spiral turn in the expandable mesh structure proximal to the distal end thereof.

24. (canceled)

25. A therapeutic apparatus for aneurysm occlusion, comprising the aneurysm occlusion device according to claim 1 and a push pod connected to the proximal end of the expandable mesh structure in the aneurysm occlusion device.

26. The therapeutic apparatus for aneurysm occlusion according to claim 25, wherein the push pod extends in a direction tangential to a spiral contour of the spiral shape of the expandable mesh structure in the expanded configuration.

27. An aneurysm occlusion system, comprising the aneurysm occlusion device according to claim 1 and a catheter, wherein the expandable mesh structure is compressed in the catheter and, after being released from the catheter, can recover the expanded configuration in which the expandable mesh structure forms the spiral shape.

28. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] FIG. 1 depicts a top view of an aneurysm occlusion device according to a preferred embodiment of the present invention, in which an expandable mesh structure has one spiral turn when in an expanded configuration, and a portion of a guide structure (a second section thereof) extends out of the expandable mesh structure from a distal end thereof and assumes a spiral shape also having one spiral turn when in an expanded configuration.

[0057] FIG. 2 depicts a perspective view of an aneurysm occlusion device according to a preferred embodiment of the present invention, in which an expandable mesh structure has two spiral turns when in an expanded configuration, and a further portion of a guide structure (a second section thereof) extends out of the expandable mesh structure from a distal end thereof and assumes a spiral shape also having two spiral turns when in an expanded configuration.

[0058] FIG. 3a depicts a top view of an aneurysm occlusion device according to a preferred embodiment of the present invention, in which an expandable mesh structure has three spiral turns when in an expanded configuration, and the further portion of a guide structure (a second section thereof) extends out of the expandable mesh structure from a distal end thereof and assumes a spiral shape also having three spiral turns when in an expanded configuration.

[0059] FIG. 3b depicts a front view of the aneurysm occlusion device of FIG. 3a.

[0060] FIG. 4 shows an aneurysm occlusion device according to a preferred embodiment of the present invention, which has been delivered into an aneurysm but not released there yet.

[0061] FIG. 5 shows an aneurysm occlusion device according to a preferred embodiment of the present invention, which has been delivered into and completely released in an aneurysm.

[0062] FIG. 6 depicts a partially enlarged view of an aneurysm occlusion device according to a preferred embodiment of the present invention, which is covering an aneurysm neck opening.

[0063] In these figures, [0064] 10 denotes an aneurysm occlusion device; [0065] 11, an expandable mesh structure; 111, a distal end of an expandable mesh structure; 112, a proximal end of an expandable mesh structure; 113, a distal section; 114, a middle section; 115, a proximal section; [0066] 12, a guide structure; 121, a distal section of a guide structure; 123, a distal end of a guide structure; 13, a proximal radiopaque ring; 14, a distal radiopaque ring; [0067] 20, a push pod; 30, an aneurysm; 40, a microcatheter; [0068] D1, an outer diameter of the largest spiral turn in a guide structure; D2, an outer diameter of the largest spiral turn in an expandable mesh structure; and D3, a maximum outer diameter of an expandable mesh structure.

[0069] Throughout the figures, the same reference numbers are used to denote the same or like elements.

DETAILED DESCRIPTION

[0070] Objects, advantages and features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. Note that the figures are provided in a very simplified form not necessarily drawn to exact scale for the only purpose of facilitating easy and clear description of the disclosed embodiments.

[0071] As used herein, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise. As used herein, the term “or” is generally employed in the sense including “and/or”, unless the context clearly dictates otherwise. The term “plurality” is generally employed in the sense including “two or more than two”, unless the context clearly dictates otherwise. The term “several” is generally employed in the sense including “an indefinite number of”, unless the context clearly dictates otherwise. The term “proximal end” generally refers to an end closer to an operator operating a medical device, and the term “distal end” generally refers to an end of the device that enters a human body first, unless the context clearly dictates otherwise.

[0072] Reference is now made to FIG. 1, which shows an aneurysm occlusion device 10 according to an embodiment of the present invention. The aneurysm occlusion device 10 is used for treatment of aneurysm occlusion. Examples of the aneurysm include, but are not limited to, intracranial aneurysms. Specifically, the aneurysm occlusion device 10 includes an expandable mesh structure 11 and a guide structure 12. At least part of the guide structure 12 is disposed in an inner cavity defined by the expandable mesh structure 11. Preferably, a first section of the guide structure 12 is disposed in the inner cavity of the expandable mesh structure 11, while a second section thereof extends out of the expandable mesh structure 11 from a distal end 111 thereof. In this way, the distal section 121 of the guide structure 12 is exposed out of the expandable mesh structure 11 at the distal end thereof.

[0073] The expandable mesh structure 11 has an expanded configuration where it spirals from the distal end 111 to a proximal end 112 thereof and a collapsed configuration for delivery into the aneurysm from a blood vessel. In some embodiments, in the expanded configuration, the expandable mesh structure 11 spirals from the distal end 111 to the proximal end 112 into a three-dimensional spiral shape. In some other embodiments, in the expanded configuration, the expandable mesh structure 11 spirals from the distal end 111 to the proximal end 112 into a planar spiral shape (i.e., a planar vortex). Additionally, the guide structure 12 is configured so that, when the expandable mesh structure 11 assumes the spiral shape, each of the first section of the guide structure 12 disposed in the inner cavity of the expandable mesh structure 11 and the second section of the guide structure 12 extending out of the expandable mesh structure 11 from the distal end 111 thereof also assumes an expanded configuration where it has a spiral shape. Preferably, the distal section 121 of the guide structure 12 assumes a spiral shape in the expanded configuration. Further, the spiral shape of the distal section 121 of the guide structure 12 may be three-dimensional or planar (i.e., a planar vortex).

[0074] When assuming the spiral shape in the expanded configuration, the distal section 121 of the guide structure 12 may spiral either in the same direction as or in a different direction from the expandable mesh structure 11. Preferably, the distal section 121 of the guide structure 12 spirals in the same direction as the expandable mesh structure 11 because this allows good guidance and can prevent bending of the spiral distal section 121 during advancement and delivery, which may affect shape recovery of the expandable mesh structure 11 within the aneurysm. Moreover, an axis about which the distal section 121 of the guide structure 12 spirals may either coincide with an axis about which the expandable mesh structure 11 spirals, or not, without limiting the present invention in any way.

[0075] In this embodiment, the expandable mesh structure 11 is configured to assume a three-dimensional spiral shape in the expanded configuration, which enables more secure support, stronger anchoring and reduced likeliness of displacement in the aneurysm. Alternatively, the expandable mesh structure 11 may be configured to be in the shape of a planar vortex in the expanded configuration, which enables the expandable mesh structure 11 to more easily recover and more stably maintain the spiral shape in the aneurysm.

[0076] It would be appreciated that the expandable mesh structure 11 and the guide structure 12 may be both resilient structures, which can be compressed by an external force and restore their shape after the external force is removed. More specifically, the expandable mesh structure 11 has a collapsed configuration and an expanded configuration. When loaded within a catheter 40 (see FIG. 4), it assumes the collapsed configuration, in which it may be compressed into a linear shape with a minimized radial size, which facilitates its delivery through the catheter 40 that has a small inner diameter. When released from the catheter 40, the expandable mesh structure 11 can expand by its own resilience into the expanded configuration, in which it recovers a spiral shape. Likewise, the guide structure 12 also has a collapsed configuration and an expanded configuration. When the guide structure 12 is loaded within the catheter 40 together with the expandable mesh structure 11, it assumes the collapsed configuration, in which it is compressed in a similar way as the expandable mesh structure 11, for example, into a linear shape that enables its delivery through the catheter 40. When released from the catheter 40, the guide structure 12 can also expand by its own resilience back into the expanded configuration. In this configuration, the guide structure 12, more preferably, the distal section 121 thereof, assumes a spiral shape.

[0077] Referring back to FIG. 1, in an embodiment of the present invention, there is also provided a therapeutic apparatus for aneurysm occlusion, including the aneurysm occlusion device 10 and a push pod 20 for advancing the aneurysm occlusion device 10. The proximal end 112 of the expandable mesh structure 11 is configured to be detachably coupled to the push pod 20. Optionally, the proximal end 112 of the expandable mesh structure 11 may be provided with a separate connecting means (not shown) for detachably coupling the push pod 20. Additionally, in the expanded configuration of the expandable mesh structure 11, the push pod 20 is preferred to extend in a direction tangential to a spiral contour of the expandable mesh structure 11. In this way, the expandable mesh structure 11 can be advanced and released so that an outer surface of its largest spiral turn covers an aneurysm neck opening 31 (see FIG. 6). Covering the aneurysm neck opening 31 with the outer surface of the largest spiral turn in the expandable mesh structure 11 can not only ensure sufficient coverage of the aneurysm neck opening 31, but can also avoid the proximal end 112 of the expandable mesh structure 11 from being located around a center of the aneurysm neck opening 31 (e.g., over a central portion thereof) and thus from easily herniating into the parent blood vessel 50 (see FIG. 5). Such herniation may affect the healing of the aneurysm neck and lead to embolism in the blood vessel. Without limiting the prevent invention, the push pod 20 may be detached from the proximal end 112 of the expandable mesh structure 11 thermally, electrically, mechanically, hydrolytically or otherwise as is conventional. The push pod 20 functions primarily to push the aneurysm occlusion device 10 out of the catheter 40 and thereby release it into the aneurysm 30.

[0078] The guide structure 12 is preferred to be an elongate structure (i.e., a linear member) in its expanded configuration. For example, it may be a spring coil or a resilient tube formed by cutting. The guide structure 12 has an outer diameter that is much smaller than an outer diameter of the expandable mesh structure 11 in the expanded configuration. In this way, the guide structure 12 is slimmer and more flexible than the expandable mesh structure 11. The guide structure 12 functions primarily to enhance support strength of the expandable mesh structure 11 by the first section disposed in the expandable mesh structure 11 and to guide the expandable mesh structure 11 by the spiral shape of the distal section (i.e., the second section) 121 so as to enable the expandable mesh structure 11 to more easily recover its own spiral shape. Moreover, the distal section 121 can relieve tension from the expandable mesh structure 11 during its release, thereby reducing its impact on the aneurysm wall and resistance to its advancement. Thus, the expandable mesh structure 11 can be more easily pushed and advanced. In particular, since the guide structure 12 is slim and flexible, it will cause less or no damage to the aneurysm wall.

[0079] Use of the inventive aneurysm occlusion device 10 will be described below with reference to FIGS. 4 to 6. However, the following description is not intended to be construed as limiting the present invention in any way. Rather, it is only intended to explain a preferred embodiment of how to operate the device.

[0080] At first, the aneurysm occlusion device 10 is loaded into the catheter 40 for delivery. The aneurysm occlusion device 10 is loaded in the collapsed configuration, in which both the expandable mesh structure 11 and the guide structure 12 are elongated, preferably, into linear shapes, resulting in an overall radial size of the device that is small enough to allow the device to be accommodated in the catheter 40 that has a small inner diameter. Optionally, the inner diameter of the catheter 40 may be 0.017 inches, 0.021 inches or 0.027 inches. After that, as shown in FIG. 4, a distal end of the catheter 40 is held stationary at a proximal end of the aneurysm 30, and the aneurysm occlusion device 10 is then released. In the release process, the push pod 20 (not shown in FIG. 4) may be manipulated to distally push the device 10 or proximally retract the catheter 40 to first release the distal section 121 (i.e., the second section 121) of the guide structure 12, which then recoils in the aneurysm into the intended spiral shape. Since the distal section 121 of the guide structure 12 is a slim flexible spiral structure, it encounters less friction in the aneurysm and thus can easily recover the spiral shape. With the aneurysm occlusion device 10 being further pushed, release of the expandable mesh structure 11 starts. Under the guidance of the spiral shape of the distal section 121 of the guide structure 12, the expandable mesh structure 11 increasingly spirals and its outer diameter continues expanding, until the entire aneurysm occlusion device 10 complete fills and packs the aneurysm, as shown in FIG. 5. At this time, the outer surface of the largest spiral turn in the aneurysm occlusion device 10 covers the aneurysm neck from an inner side thereof, and the whole device stably spirals within the aneurysm 30, achieving stable, compliant packing. Finally, after desired packing quality is confirmed, the push pod 20 may be electrically detached from the proximal end 112 of the expandable mesh structure 11, and the microcatheter 40 and push pod 20 may be withdrawn, ending the process for occluding the aneurysm 30. It is to be noted that, in FIGS. 4 to 6, for ease of illustration, the section of the guide structure 12 in the expandable mesh structure 11 is not shown.

[0081] As shown in FIG. 5, after the completion of the occlusion process, a distal end of the aneurysm occlusion device 10, especially the distal end of the expandable mesh structure 11, is not oriented toward the aneurysm wall and thus has no impact thereon. Moreover, the proximal end of the expandable mesh structure 11 is confined between the outer surface of the largest spiral turn in the expandable mesh structure 11 and the aneurysm wall so as to be oriented in parallel to the aneurysm wall. Thus, both the proximal and distal ends of the device have no impact on the aneurysm wall. In addition, the only portion contacting the aneurysm wall is a braided dense mesh. This enables the aneurysm wall to be more uniformly stressed and less damaged. In particular, the expandable mesh structure 11 provides multiple barriers, which can desirably block blood flow and facilitate thrombosis in the aneurysm, thus accelerating embolization of the aneurysm. With additional reference to FIG. 6, it is the outer surface of the largest spiral turn in the expandable mesh structure 11 that blocks the aneurysm neck opening 31 by fitting against the inner wall of the aneurysm 30. This enables the device to have good stability. Further, it is unlikely for a proximal end of the device to herniate into the parent blood vessel 50 (see FIG. 5) and affect endothelialization over the aneurysm neck. Therefore, healing of the aneurysm neck opening can be accelerated, and good embolization results can be obtained. In particular, in case of the expandable mesh structure 11 assuming a planar spiral shape in the expanded configuration, the distal end of the device can be completely wrapped within the expandable mesh structure 11. This additionally reduces the chance of the distal end having an impact on the aneurysm wall and even more effectively lowers the risk of rupture of the aneurysm.

[0082] Further, at least part of the guide structure 12 is formed of a radiopaque material. More preferably, the first section of the guide structure 12 disposed in the inner cavity of the expandable mesh structure 11 is made of a radiopaque material. The radiopacity of the guide structure 12 under X-ray fluoroscopy enables easy location of the expandable mesh structure 11 and dispenses with the use of a separate radiopaque component, resulting in increased structural simplicity. As a result, the expandable mesh structure 11 is more compliant and can more easily recover the spiral shape in the aneurysm. Further, the guide structure 12 may be overall radiopaque. For example, it may be entirely made of a radiopaque material. The present invention is not limited to any particular radiopaque material of the guide structure 12, and for example, platinum (Pt), platinum-iridium (Pt—Ir) alloys, gold (Au), platinum-tungsten (Pt—W) alloys and the like can be suitably used. In some embodiments, the guide structure 12 may be formed of a non-radiopaque material, such as a nickel-titanium alloy or stainless steel. In a particular embodiment, the guide structure 12 may be obtained by densely winding a metal wire (e.g., a platinum-tungsten alloy, a nickel-titanium alloy, stainless steel or the like) on a metal core bar into a primary coil and then shaping a distal section 121 of the primary coil (which is a linear structure, also called a coil) into the spiral-shaped distal section 121 of the guide structure 12. In another embodiment, the guide structure 12 may be obtained by cutting a metal tube into a flexible mesh tube and stretching the flexible mesh tube into an elongate shape. Preferably, a distal section 121 of the tube is further shaped into the spiral-shaped distal section 121 of the guide structure 12. In yet another embodiment, the guide structure 12 may be a braided structure. For example, filaments may be braided into a tube, which may be then stretched into an elongate shape. Further, a distal section 121 thereof may be further shaped into the spiral-shaped distal section 121 of the guide structure 12. It would be appreciated that, in further embodiments, the fabrication of the guide structure 12 may only involve obtaining an elongate linear structure by braiding, cutting or otherwise but not a stretching process. Furthermore, a distal end 123 of the guide structure 12 is preferably smooth. For example, a light-curable adhesive may be applied to the distal end 123 and then cured there to form a smooth dome-shaped tip, which can reduce damage caused to the aneurysm wall.

[0083] The expandable mesh structure 11 is preferably formed of a spirally wound braided tube. Preferably, the braided tube is formed of 48-144 filaments with an outer diameter of 0.0005-0.002 inches. In this way, a dense mesh with a high mesh opening density can be constructed, which can effectively block blood flow and promote thrombosis in the aneurysm and allows better coverage of the aneurysm neck and more uniform stressing of the aneurysm wall, thus additionally reducing the risk of rupture of the aneurysm. Materials suitable for fabrication of the filaments may include shape memory materials, which may be metal materials with shape memory properties, such as nickel-titanium (Ni—Ti) alloys, nickel-titanium-cobalt alloys (Ni—Ti—Co), double-layer composite metal wires (e.g., Ni—Ti@Pt), etc. Suitable materials for the filaments may also include polymer materials with certain shape recovery properties, such as polydioxanone (PDO), poly(l-lactide-co-e-caprolactone) (PLC), polyurethane (PU), amorphous polynorbornene or combinations thereof. Making the filaments out of a shape memory metal material or a polymer material with certain shape recovery properties can imparts shape memory properties to the braided mesh, which can facilitate the recovery of the original shape. Preferably, the expandable mesh structure 11 is braided from radiopaque filaments. Alternatively, the expandable mesh structure 11 may be braided from both radiopaque and non-radiopaque filaments. With this design, the expandable mesh structure 11 is itself radiopaque under X-ray fluoroscopy, while exhibiting sufficient resilience, which enables the expandable mesh structure 11 to have strong ability to recover and maintain its original shape, thereby dispensing with the use of a separate radiopaque component and increasing compliance of the expandable mesh structure 11. The present invention is not limited to any particular radiopaque material of the radiopaque filaments, and for example, platinum (Pt), platinum iridium alloys (Pt—Ir), gold (Au), platinum-tungsten (Pt—W) alloys and the like can be suitably used. It would be also appreciated that, in case of the guide structure 12 being radiopaque, it is possible for the expandable mesh structure 11 to be either radiopaque or not.

[0084] The spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration may have one or more spiral turns. Considering that an excessive outer diameter of the spiral-shaped distal section 121 of the guide structure 12 tends to adversely affect the advancement or expansion of the expandable mesh structure 11, an outer diameter D1 of the largest spiral turn in the spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration is limited to not exceed an outer diameter of a first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof. This condition applies to the case that the distal section 121 of the guide structure 12 has one or more spiral turns. Moreover, when the spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration has a plurality of spiral turns, an outer diameter of a first one of the spiral turns proximal to the distal end of the guide structure 12 is preferably smaller than an outer diameter of any other spiral turn in the guide structure 12, which is preferably not exceed the outer diameter of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof. The outer diameters of the other spiral turns in the guide structure 12 may be equal or not, and are preferred to be equal. Here, it would be appreciated that, in case of the distal section 121 of the guide structure 12 having a planar spiral shape, the outer diameters of the other spiral turns in the guide structure 12 are not equal, and in case of the distal section 121 of the guide structure 12 having a three-dimensional spiral shape, the outer diameters of the other spiral turns in the guide structure 12 may be equal or not. Moreover, the outer diameter of the first spiral turn in the guide structure 12 proximal to the distal end thereof is ⅔-¾ of the outer diameter of any other spiral turn in the guide structure 12, which is preferably not smaller than ⅔ of the outer diameter of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof. This design is advantageous in that, during the release and shape recovery of the expandable mesh structure 11, it can provide a space for the packing by the expandable mesh structure 11 and prevent the spiral turns in the distal section 121 of the guide structure 12 from occupying additional space and hence from affecting the release and shape recovery of the expandable mesh structure 11 in the aneurysm. It would be appreciated that the first spiral turn of the guide structure 12 refers to its most distal spiral turn. It would be appreciated that, for a planar spiral shape, an outer diameter of its largest spiral turn is just its maximum outer diameter, while for a three-dimensional spiral shape, an outer diameter of its largest spiral turn is a maximum outer diameter of its axial projection. The largest spiral turn refers to a spiral turn with the largest outer diameter.

[0085] The number of spiral turns in the expandable mesh structure 11 may be determined according to the actual size of an aneurysm to be treated. Fewer spiral turns make the expandable mesh structure 11 suitable for use in the treatment of a smaller aneurysm, and more spiral turns enable it to be used in the treatment of a bigger aneurysm. In this embodiment, the spiral-shaped expandable mesh structure 11 in the expanded configuration may have one or more spiral turns, optionally 1-3 spiral turns. Further, considering that when the number of spiral turns is greater than 3, the aneurysm occlusion device 10 will encounter increased resistance to advancement and greater friction during shape recovery in the aneurysm, which may make it difficult for the expandable mesh structure 11 to recover the spiral shape, the spiral-shaped expandable mesh structure 11 in the expanded configuration preferably has no more than 3 spiral turns, more preferably, 1-3 spiral turns.

[0086] In this embodiment, in case of the spiral-shaped expandable mesh structure 11 in the expanded configuration having a plurality of spiral turns, for example, as shown in FIG. 3b, the outer diameter d1 of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof is preferably smaller than an outer diameter d2 of any middle one of the spiral turns in the expandable mesh structure 11. More preferably, an outer diameter d3 of a last one of the spiral turns in the expandable mesh structure 11 proximal to the proximal end thereof is also smaller than the outer diameter d2 of any middle spiral turn in the expandable mesh structure 11. It would be appreciated that a middle spiral turn refers to another spiral turn than the first spiral turn proximal to the distal end and the last spiral turn proximal to the proximal end. This design is advantageous in facilitating shape recovery of the expandable mesh structure 11 by minimizing resistance, and in providing sufficient support, which can further stabilize the aneurysm occlusion device 10 and enables it to completely pack the interior of the aneurysm with an increased packing density. Preferably, the outer diameter d1 of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof is equal to the outer diameter d3 of the last spiral turn proximal to the proximal end, as shown in FIGS. 3a and 3b. Moreover, the outer diameter d1 of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof may be ⅔ of the outer diameter d2 of any middle spiral turn in the expandable mesh structure 11. In addition, when the expandable mesh structure 11 has a plurality of middle spiral turns, these middle spiral turns are preferred to have equal outer diameters d2. It would be appreciated that the first spiral turn of the expandable mesh structure 11 refers to its most distal spiral turn.

[0087] For example, as shown in FIG. 1, the spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration may have one spiral turn, and the spiral-shaped expandable mesh structure 11 in the expanded configuration may also have one spiral turn. In this case, preferably, the proximal end 112 and the distal end 111 of the expandable mesh structure 11 are located at the same radial position on the same side of an axis of spiral thereof. Moreover, the expandable mesh structure 11 spirals in the same direction as the distal section 121 of the guide structure 12. More preferably, the outer diameter D1 of the largest spiral turn in the guide structure 12 is ⅔ of an outer diameter D2 of the largest spiral turn in the expandable mesh structure 11. Additionally, the maximum outer diameter D3 of the expandable mesh structure 11 is preferably ½ of the outer diameter D2 of the largest spiral turn. In this example, the guide structure 12 can guide shape recovery of the expandable mesh structure 11 within the aneurysm through the single spiral turn of the distal section 121 and reduce damage to the aneurysm wall caused by the distal end of the expandable mesh structure 11.

[0088] Alternatively, as shown in FIG. 2, the spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration may have two spiral turns, and the spiral-shaped expandable mesh structure 11 in the expanded configuration may also have two spiral turns. In this case, the outer diameter of first spiral turn in the guide structure 12 proximal to the distal end thereof is preferably ⅔ of the outer diameter of the second spiral turn, which is preferably equal to the outer diameter d1 of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof. Moreover, the outer diameter d1 of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof is preferably ¾ of the outer diameter d2 of the second (largest) spiral turn therein. In addition, the maximum outer diameter D3 of the expandable mesh structure 11 is preferably ⅓ of the outer diameter D2 of its largest spiral turn. Compared with the case of a single spiral turn, the expandable mesh structure 11 with two spiral turns is able to more completely pack the aneurysm, enables better coverage of the aneurysm neck opening by the outer surface of the largest spiral turn and can be used in the treatment of a bigger aneurysm.

[0089] Still alternatively, as shown in FIGS. 3a and 3b, the spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration may have three spiral turns, and the spiral-shaped expandable mesh structure 11 in the expanded configuration may also have three spiral turns. In this case, the outer diameter of the first spiral turn in the guide structure 12 proximal to the distal end thereof is preferably ⅔ of the outer diameter of the second spiral turn, which is equal to the outer diameter of the third spiral turn. More preferably, the outer diameter of the third spiral turn in the guide structure 12 is equal to the outer diameter d1 of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof, which is preferably ⅔ of the outer diameter d2 of the second spiral turn. The outer diameter d3 of the third spiral turn in the expandable mesh structure 11 is preferred to be ⅔ of the outer diameter d2 of the second spiral turn. That is, the second spiral turn in the expandable mesh structure 11 has the largest outer diameter d2. Further, the maximum outer diameter D3 of the expandable mesh structure 11 is preferably ¼ of the outer diameter D2 of the largest spiral turn. In this case, since the expandable mesh structure 11 has more spiral turns, it is able to even more completely pack the aneurysm, enables even better coverage of the aneurysm neck opening by the outer surface of at least one spiral turn and can be used in the treatment of an even bigger aneurysm.

[0090] It would be appreciated that, in the expanded configuration, the present invention is not limited to the above examples because the expandable mesh structure 11 may include even more spiral turns. In addition, the number of spiral turns in the expandable mesh structure 11 may be equal to the number of spiral turns in the distal section 121 of the guide structure 12 or not, without departing from the scope of the present invention. It would be appreciated that the expandable mesh structure 11 with more spiral turns can even more completely pack the aneurysm and be used in the treatment of an even bigger aneurysm.

[0091] Further, in case of the spiral-shaped distal section 121 of the guide structure 12 in the expanded configuration having a plurality of spiral turns, the outer diameter of the first spiral turn of the guide structure 12 proximal to the distal end thereof is slightly smaller than, preferably ⅔-¾ of, the outer diameter of any other spiral turn in the guide structure 12. The outer diameter of any other spiral turn in the guide structure 12 than the first spiral turn is preferred to be not smaller than ⅔ of, but not exceed, the outer diameter of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof.

[0092] Further, in the expanded configuration, the maximum outer diameter D3 of the expandable mesh structure 11 is preferably not smaller than ¼, more preferably ⅓-½, of the outer diameter D2 of the largest spiral turn in the expandable mesh structure 11. This is advantageous in ensuring sufficient friction between the outer surface of the largest spiral turn in the expandable mesh structure 11 and the aneurysm wall, which prevents easy displacement of the aneurysm occlusion device 10 and disperses the support from the aneurysm occlusion device 10 to avoid the aneurysm wall from being damaged due to excessive local pressure. Additionally, it can be ensured that the outer surface of the largest spiral turn in the expandable mesh structure 11 covers the aneurysm neck as much as possible to accelerate thrombosis in the aneurysm. In this embodiment, the outer diameter D2 of the largest spiral turn in the expandable mesh structure 11 is determined principally according to the size of the aneurysm to be treated. For example, the maximum outer diameter D3 of the expandable mesh structure 11 may be 2.0-8.0 mm, and the outer diameter D2 of the largest spiral turn therein may be 3.0-25 mm.

[0093] Further, in order to facilitate advancement of the expandable mesh structure 11, the proximal end 112 and the distal end 111 of the expandable mesh structure 11 are preferably both secured to the guide structure 12. Preferably, an axial length of the first section of the guide structure 12 disposed in the inner cavity of the expandable mesh structure 11 in the expanded configuration is not smaller than an axial length of the expandable mesh structure 11 in the collapsed configuration. This ensures that the expandable mesh structure 11 can be successfully compressed and can successfully expand without being affected by the guide structure 12.

[0094] Additionally, a proximal radiopaque ring 13 may be attached to the proximal end 112 of the expandable mesh structure 11. On one aspect, the radiopacity of the proximal radiopaque ring 13 under X-ray fluoroscopy allows location of the proximal end 112 of the expandable mesh structure 11 and increases overall radiopacity of the entire device. On another aspect, end portions of filaments in the expandable mesh structure 11 can be hidden within the proximal radiopaque ring 13 and thus cause less damage to the aneurysm wall. Further, a distal radiopaque ring 14 may be attached to the distal end 111 of the expandable mesh structure 11 (see FIG. 1). On one aspect, the radiopacity of the distal radiopaque ring 14 under X-ray fluoroscopy allows location of the distal end 111 of the expandable mesh structure 11 and increases the overall radiopacity of the entire device. On another aspect, end portions of filaments in the expandable mesh structure 11 can be hidden within the distal radiopaque ring 14 and thus cause less damage to the aneurysm wall. Optionally, the proximal radiopaque ring 13 may be attached with an adhesive to both the proximal end 112 of the expandable mesh structure 11 and the proximal end 122 of the guide structure 12. Similarly, the distal radiopaque ring 14 may be attached with an adhesive to both the distal end 111 of the expandable mesh structure 11 and the guide structure 12. It would be appreciated that, when the expandable mesh structure 11 itself, or the guide structure 12, is radiopaque, the proximal radiopaque ring 13 and/or the distal radiopaque ring 14 may be either provided or not.

[0095] In this embodiment, a cross-sectional area of the expandable mesh structure 11 is preferred to increase and then decrease from the proximal end 112 to the distal end 111, as particularly shown in FIGS. 1 and 2. In this case, the outer diameter of the expandable mesh structure 11 is not constant. Additionally, the expandable mesh structure 11 includes, sequentially joined side by side axially, a distal section 113, a middle section 114 and a proximal section 115. The distal section 113 preferably has a cross-sectional area (or outer diameter) increasing from the distal end 111 to the middle section 114, and/or the proximal section 115 preferably has a cross-sectional area (or outer diameter) increasing from the proximal end 112 to the middle section 114. In other embodiments, the cross-sectional area of the expandable mesh structure 11 may repeatedly increase and decrease from the proximal end 112 to the distal end 111. That is, it may repeatedly widen and narrow. This design can facilitate configuration of the expandable mesh structure 11 into a fusiform shape (swollen at the middle and tapering to each end), which makes it easy to be compressed into a smaller size. Moreover, it enables the aneurysm occlusion device to be more flexible and pushed and advanced while experiencing less resistance and exerting a reduced impact on the aneurysm wall. The distal section 113 of the expandable mesh structure 11 can function as a guide means, which facilitates shape recovery of the expandable mesh structure 11. The expandable mesh structure 11 may have a greater mesh opening density at both the distal section 113 and the proximal section 115. In particular, a greater mesh opening density of the distal section 113 enables the aneurysm occlusion device 10 to have increased strength, better support stability within the spiral shape and higher resistance to displacement. The present invention is not limited to any particular mesh opening density distribution of the middle section 114 of the expandable mesh structure 11, and for example, the middle section 114 may have a uniform or non-uniform mesh opening density.

[0096] It would be appreciated that, the distal section 121 of the guide structure 12, as well as the expandable mesh structure 11, may alternatively assume the shape of a planar spiral. In this case, the distal section 121 of the guide structure 12 may spiral in the same direction as the expandable mesh structure 11, preferably within the same plane. In addition, in case of the expandable mesh structure 11 being in the shape of a planar spiral, it may define a bulge at the proximal end 112, which can increase friction between the expandable mesh structure 11 and the aneurysm wall, enhance stability of the device, reduce the risk of herniation of the proximal section 115, lower the risk of vascular embolism, improve coverage of the aneurysm neck and accelerate thrombosis in the aneurysm. The bulge may be implemented as a circumferentially continuous closed flange. That is, the bulge may be made up of one circumferentially continuous monolithic ring. Alternatively, the bulge may be implemented as a circumferentially non-continuous closed flange. That is, it may be made up of multiple sectorial projections, which are spaced apart circumferentially. Still alternatively, the bulge may be implemented as an unclosed ring extending circumferentially around the proximal section 115, such as for example, a ¼ ring, a half ring or a ¾ ring. Further, in case of the distal section 121 of the guide structure 12 being also in the shape of a planar spiral, the outer diameter of the largest spiral turn in the guide structure 12 is preferred not to exceed the outer diameter of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof, in order to avoid affecting advancement and shape recovery of the expandable mesh structure 11. Preferably, in order to enhance overall strength of the entire device, the outer diameter of the largest spiral turn in the guide structure 12 is not smaller than ⅔ of the outer diameter of the first spiral turn in the expandable mesh structure 11 proximal to the distal end thereof. Further, in order for better shape recovery and easier size control to be achieved, adjacent spiral turns in the expandable mesh structure 11 in the shape of a planar vortex are preferably brought in contact with each other.

[0097] In embodiments of the present invention, there is also provided an aneurysm occlusion system including the aneurysm occlusion device 10 and the catheter 40. The expandable mesh structure 11 is compressed within the catheter 40 and, after being released from the catheter 40, recovers the expanded configuration in which it assumes the spiral shape.

[0098] At last, it is to be noted that, although a few preferred embodiments of the present invention have been described above, the scope of the invention is in no way limited to these embodiments disclosed hereinabove. For example, the present invention is not limited to any particular number of spiral turns in the expandable mesh structure 11 in the expanded configuration, or any particular number of spiral turns in the guide structure 12 in the expanded configuration, or any particular outer diameter of the largest spiral turn in the expandable mesh structure 11 in the expanded configuration, or any particular length of the guide structure 12 within the expandable mesh structure 11. It is to be also noted that, in other embodiments, the guide structure 12 may be entirely disposed in the inner cavity of the expandable mesh structure 11.

[0099] Thus, embodiments of the present invention provide an aneurysm occlusion device capable of easier blocking of the neck of an aneurysm while not exerting any impact on a wall of the aneurysm at its distal or proximal end, thereby avoiding the risk of rupture of the aneurysm, increasing coverage of the aneurysm neck and facilitating thrombosis in the aneurysm. Additionally, the present invention can circumvent the problem that a proximal anchor of the expandable structure is located around a center of an opening of the aneurysm neck and may herniate into the parent blood vessel. In this way, endothelialization of the aneurysm neck can be accelerated, and the risk of vascular stenosis can be avoided.

[0100] The description presented above is merely that of a few preferred embodiments of the present invention and does not limit the scope thereof in any sense. Any and all changes and modifications made by those of ordinary skill in the art based on the above teachings fall within the scope as defined in the appended claims