Embolic device for occluding a body lumen

Abstract

An embolization device for placement in a body cavity includes: an elongated member having a linear configuration when at room temperature, the elongated member being configured to form a first three-dimensional structure in response to body temperature; wherein the elongated member includes a first segment, a second segment, and a third segment, the second segment being located between the first segment and the third segment; wherein the first segment and the third segment are configured to change their respective shapes in response to body temperature; and wherein the second segment located between the first segment and the third segment has a shape independent of body temperature.

Description

[0001] field

[0002] The scope of this disclosure relates to medical devices and methods for occluding body cavities, and more specifically, to medical devices and methods for occluding aneurysms.

[0003] background

[0004] An aneurysm is a dilated blood vessel that can rupture, clot, or disintegrate, posing a risk to health. A ruptured cerebral aneurysm can cause a stroke, while a ruptured abdominal aneurysm can cause shock. Cerebral aneurysms are often discovered in patients due to seizures or bleeding, and they can lead to a high morbidity or mortality rate.

[0005] Various materials and devices have been used to treat aneurysms, including platinum and stainless steel microcoils, polyvinyl alcohol sponge (Ivalone), and other mechanical devices. For example, a vascular occlusion device is a surgical instrument or implant that is typically placed in the body's vascular system via a catheter to block blood flow through the blood vessels that make up that part of the vascular system by forming an embolus, or to form such an embolus within an aneurysm originating from that blood vessel.

[0006] Sometimes, when a vascular occlusion device is carried within a catheter, it elastically bends to conform to the catheter's profile. This elastic bending creates various pressure points on the inner surface of the catheter, which can be undesirable as it makes advancement of the occlusion device relative to the catheter more difficult. In some cases, it may be necessary to apply an increased axial force to push the occlusion device distally. This increased axial force can sometimes cause premature buckling of the occlusion device within the catheter.

[0007] Furthermore, the vascular occlusion device may take on a certain three-dimensional shape after it is deployed outside the catheter. If the deployed vascular occlusion device is too rigid, it may not conform to the shape of the body cavity that the vascular occlusion device is intended to occlude. On the other hand, if the deployed vascular occlusion device is too flexible, it may not be able to maintain its shape and may unintentionally bend into an undesirable shape, thus failing to occlude the body cavity.

[0008] Overview

[0009] An embolic device for placement in a body cavity includes: an elongated member having a linear configuration at room temperature, the elongated member being configured to form a first three-dimensional structure in response to body temperature; wherein the elongated member includes a first segment, a second segment, and a third segment, the second segment being located between the first segment and the third segment; wherein the first segment and the third segment are configured to change their respective shapes in response to body temperature; and wherein the second segment located between the first segment and the third segment has a shape independent of body temperature.

[0010] Optionally, in response to body temperature, the first segment is configured to form the first part of the loop, and the third segment is configured to form the second part of the loop.

[0011] Optionally, in response to body temperature, the first segment is configured to form a first ring, and the third segment is configured to form a second ring.

[0012] Optionally, the first segment has a first length, the second segment has a second length, and the third segment has a third length; wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0013] Optionally, the second length of the second segment located between the first segment and the third segment is less than 50% of the first length of the first segment, and also less than 50% of the third length of the third segment.

[0014] Optionally, the elongated member has a distal end and a proximal end opposite to the distal end, and wherein the embolization device further includes a fourth segment containing the proximal end; and wherein the fourth segment is martensitic at room temperature and also martensitic at body temperature.

[0015] Optionally, the first segment is martensitic when at room temperature and austenitic when at body temperature.

[0016] Optionally, the second segment is martensitic when at room temperature, and is martensitic when at body temperature.

[0017] Optionally, the three-dimensional structure includes multiple rings, and wherein the first segment, the third segment, and the fourth segment each comprise a corresponding portion of one of these rings.

[0018] Optionally, the elongated member further includes a fourth segment, a fifth segment, and a sixth segment, the fourth segment, the fifth segment, and the sixth segment comprising corresponding portions of another ring among these rings; wherein the fifth segment is located between the fourth segment and the sixth segment; wherein the fourth segment and the sixth segment are configured to change their respective shapes in response to body temperature; and wherein the fifth segment located between the fourth segment and the sixth segment has a shape independent of body temperature.

[0019] An embolization device for placement in a body cavity includes: an elongated member having a linear configuration at room temperature, the elongated member being configured to form a first three-dimensional structure in response to body temperature; wherein the elongated member includes a first segment, a second segment, and a third segment, the second segment being located between the first segment and the third segment; wherein the first segment is martensitic at room temperature and austenitic at body temperature; and wherein the second segment is martensitic at room temperature and also martensitic at body temperature.

[0020] Optionally, in response to body temperature, the first segment is configured to form the first part of the loop, and the third segment is configured to form the second part of the loop.

[0021] Optionally, in response to body temperature, the first segment is configured to form a first ring, and the third segment is configured to form a second ring.

[0022] Optionally, the first segment has a first length, the second segment has a second length, and the third segment has a third length; wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0023] Optionally, the second length of the second segment located between the first segment and the third segment is less than 50% of the first length of the first segment, and also less than 50% of the third length of the third segment.

[0024] Optionally, the elongated member has a distal end and a proximal end opposite to the distal end, and wherein the embolization device further includes a fourth segment containing the proximal end; and wherein the fourth segment is martensitic when at room temperature, and is also martensitic when at body temperature.

[0025] Optionally, the three-dimensional structure includes multiple rings, and the first segment, the second segment, and the third segment include corresponding portions of one of these rings.

[0026] Optionally, the elongated member further includes a fourth segment, a fifth segment, and a sixth segment, the fourth segment, the fifth segment, and the sixth segment comprising a corresponding portion of another ring among these rings; wherein the fifth segment is located between the fourth segment and the sixth segment; wherein the fourth segment and the sixth segment are martensitic at room temperature and austenitic at body temperature; and wherein the fifth segment is martensitic at room temperature and also martensitic at body temperature.

[0027] A method for occluding a body cavity via an embolization device having an elongated member comprising a first segment, a second segment, and a third segment, wherein the second segment is located between the first segment and the third segment, the method comprising: performing a first shape change via the first segment of the elongated member in response to body temperature; performing a second shape change via the second segment of the elongated member in response to force; and performing a third shape change via the third segment of the elongated member in response to body temperature.

[0028] Optionally, the first segment is martensite at room temperature and austenite at body temperature; and wherein the second segment is martensite at room temperature and also martensite at body temperature.

[0029] Optionally, in response to body temperature, the first segment forms the first part of the loop, and the third segment forms the second part of the loop.

[0030] Optionally, in response to body temperature, the first segment forms the first loop, and the third segment forms the second loop.

[0031] Optionally, the first segment has a first length, the second segment has a second length, and the third segment has a third length; wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0032] Optionally, the second length of the second segment located between the first segment and the third segment is less than 50% of the first length of the first segment, and also less than 50% of the third length of the third segment.

[0033] Optionally, the elongated member has a distal end and a proximal end opposite to the distal end, and wherein the embolization device further includes a fourth segment containing the proximal end; and wherein the fourth segment is martensitic when at room temperature, and is also martensitic when at body temperature.

[0034] Optionally, the three-dimensional structure includes multiple rings, and the first segment, the second segment, and the third segment include corresponding portions of one of these rings.

[0035] Optionally, the elongated member further includes a fourth segment, a fifth segment, and a sixth segment, the fourth segment, the fifth segment, and the sixth segment comprising a corresponding portion of another ring among these rings; wherein the fifth segment is located between the fourth segment and the sixth segment; wherein the fourth segment and the sixth segment are martensitic at room temperature and austenitic at body temperature; and wherein the fifth segment is martensitic at room temperature and also martensitic at body temperature.

[0036] Other and further aspects and features will become apparent from the following detailed description. Attached Figure Description

[0037] The accompanying drawings illustrate the design and use of embodiments, wherein similar elements are indicated by common reference numerals. These drawings are not necessarily drawn to scale. A more specific description of the embodiments illustrated in the drawings will be given to better understand how the above and other advantages and objects are obtained. These drawings depict exemplary embodiments only and are therefore not intended to limit the scope of the claims.

[0038] Figure 1 The illustration shows a medical device with a catheter for delivering an embolic device.

[0039] Figure 2 The diagram shows... Figure 1 The medical device, in particular, shows the distal segment of the embolization device being delivered through the catheter.

[0040] Figure 3 The diagram shows... Figure 1 An example of a medical device is shown, in particular, the shape of the device when at room temperature.

[0041] Figure 4 The diagram shows... Figure 3 The medical device is shown in particular in its shape when at body temperature.

[0042] Figure 5 The diagram shows... Figure 1 Another example of a medical device, specifically showing the shape of the device when at room temperature.

[0043] Figure 6 The diagram shows... Figure 5 The medical device is shown in particular in its shape when at body temperature.

[0044] Figure 7 It is a stress-strain diagram, which specifically shows the effects of thermal cycling.

[0045] Figures 8A-8B The diagram illustrates the use of Figure 1 Methods for developing medical devices.

[0046] Figure 9 The illustration shows a method for delivering an embolization device into an aneurysm.

[0047] Detailed description

[0048] Various embodiments are described below with reference to the accompanying drawings. It should be noted that the drawings are not drawn to scale, and in all drawings, elements with similar structures or functions are represented by the same reference numerals. It should also be noted that these drawings are intended only to facilitate the description of the embodiments. They are not intended as an exhaustive description of the invention or a limitation on the scope of the invention. Furthermore, the illustrated embodiments do not necessarily possess all the aspects or advantages shown. Aspects or advantages described in connection with a particular embodiment are not necessarily limited to that embodiment and may be practiced in any other embodiment even if not so illustrated or so explicitly described.

[0049] Figure 1 The illustration shows a medical device 10 having a catheter 20 for delivering an embolization device 100 into a body cavity. The catheter 20 has a distal end 22, a proximal end 24, and a catheter body 26 extending between the distal end 22 and the proximal end 24. The embolization device 100 is housed within a lumen 28 of the catheter 20. The medical device 10 also includes a shaft 30 located within the lumen 28 for extending the embolization device 100 out of the lumen 28 of the catheter 20.

[0050] like Figure 1 As shown, the embolization device 100 is made of an elongated member 102 having a distal end 104, a proximal end 106, and a body 108 extending between the distal end 104 and the proximal end 106. When at room temperature inside the catheter 20, the elongated member 102 of the embolization device 100 has a linear configuration (e.g., a straight profile). The elongated member 102 is configured to form a three-dimensional structure 112 in response to body temperature when it is delivered outside the catheter 20 and into the patient's body. Figure 2 ).

[0051] Figure 3An example of an embolization device 100 is illustrated. As shown, the elongated member 102 of the embolization device 100 has a relatively straight linear configuration when at room temperature. The elongated member 102 is configured to form a three-dimensional structure in response to body temperature. Therefore, the straight profile of the elongated member 102 in the catheter 20 is primarily due to the elongated member 102 being at room temperature, rather than primarily due to any mechanical straightening caused by the catheter 20. This feature is advantageous because it reduces friction between the elongated member 102 and the inner wall of the catheter 20, making it easier to advance the embolization device 100 distally. If desired, this feature also allows for the delivery of a longer embolization device 100.

[0052] In the illustrated embodiment, the elongated member 102 has a first segment 300, a second segment 302, and a third segment 304. The second segment 302 is located between the first segment 300 and the third segment 304. The first segment 300 and the third segment 304 are configured to change their respective shapes in response to body temperature. The second segment 302, located between the first segment 300 and the third segment 304, has a shape independent of body temperature.

[0053] It should be noted that, as used herein, the term "body temperature" may refer to a range of temperatures, such as 95°F to 107°F, or more preferably 96°F to 100°F, or even more preferably 97°F to 99°F. Furthermore, as used herein, the term "room temperature" may refer to any temperature different from body temperature. For example, room temperature may be any temperature lower than body temperature. In some embodiments, room temperature may be any temperature at least 10°F or at least 20°F lower than body temperature.

[0054] In the illustrated embodiment, the first segment 300 is martensitic at room temperature and austenitic at body temperature. The second segment 302 is martensitic at room temperature and austenitic at body temperature. The third segment 304 is martensitic at room temperature and austenitic at body temperature. Therefore, the first and third segments 300 are reversible martensitic segments, allowing them to have relatively straight profiles at room temperature and to change into austenitic segments in response to body temperature. On the other hand, the second segment 302 is an irreversible martensitic segment, which allows the second segment 302 to have a relatively straight profile at both room temperature and body temperature.

[0055] In the illustrated embodiment, the second segment 302 is softer than the first segment 300 and the third segment 304. This allows the second segment 302 to bend more readily in response to forces compared to the first segment 300 and the third segment 304.

[0056] It should be noted that, as used in this specification, the term "straight" may be used to describe the straight or curved delivery shape of the embolization device 100, provided that the curvature of the delivery shape is less than the curvature of the embolization device 100 in its unfolded shape.

[0057] like Figure 4 As shown, the elongated member 102 is configured to form a three-dimensional structure 112 comprising a plurality of rings 400 in response to body temperature after the elongated member 102 is deployed. As shown, the first segment 300, the second segment 302, and the third segment 304 are portions of one of these rings 400. Therefore, in response to body temperature, the first segment 300 is configured to form a first portion of the ring 400, and the third segment 304 is configured to form a second portion of the same ring 400.

[0058] As shown in the figure, the elongated member 102 also includes a fourth segment 410, a fifth segment 412, and a sixth segment 414, which are part of another ring of these rings 400. The fifth segment 412 is located between the fourth segment 410 and the sixth segment 414. The fourth segment 410 and the sixth segment 414 are configured to change their respective shapes in response to body temperature. The fifth segment 412, located between the fourth segment 410 and the sixth segment 414, has a shape independent of body temperature. In some embodiments, when the fourth segment 410 and the sixth segment 414 are at room temperature, the fourth segment 410 and the sixth segment 414 are martensite, and when the fourth segment 410 and the sixth segment 414 are at body temperature, the fourth segment 410 and the sixth segment 414 are austenite; and wherein when the fifth segment 412 is at room temperature, the fifth segment 412 is martensite, and when the fifth segment 412 is at body temperature, the fifth segment 412 is also martensite.

[0059] In some embodiments, the elongated member 102 may include multiple sets of three segments, each set of three segments being configured to form a loop (or other desired curved shape) of the three-dimensional structure 112. In each set of three segments, the first and third segments are configured to change shape in response to body temperature, and the second segment located between the first and third segments has a shape independent of body temperature. Therefore, when the elongated member 102 is delivered from outside the patient to inside the patient, the elongated member 102 undergoes a temperature change from room temperature to body temperature. As a result, the first and third segments in each set of elongated members 102 will change their shape in response to body temperature, and the second segments in these sets of elongated members 102 will not respond to body temperature and will not change their shape due to body temperature.

[0060] In some embodiments, the first segment 300 has a first length, the second segment 302 has a second length, and the third segment 304 has a third length. The second length of the second segment 302 is shorter than the first length of the first segment 300 and also shorter than the third length of the third segment 304. For example, the second length of the second segment 302 located between the first segment 300 and the third segment 304 may be less than 50% of the first length of the first segment and also less than 50% of the third length of the third segment.

[0061] In the above embodiments, the second segment 302 is described as being located between the first segment 300 and the third segment 304, wherein all three segments 300, 302, and 304 are part of a ring. In other embodiments, the second segment 302 may be located at other positions. For example, in other embodiments, the second segment 302 may be located closer to one end of the ring. In this case, the respective lengths of the first segment 300 and the third segment 304 may be different from each other. As another example, in other embodiments, the second segment 302 may be located between two rings. In this case, in response to body temperature, the first segment 300 is configured to form a first ring, and the third segment 304 is configured to form a second ring. The second segment 302 located between the two rings (formed by the first segment 300 and the third segment 304) does not change shape in response to body temperature. Instead, the second segment 302 may be configured to change shape in response to force. In some cases, the second segment 302 may be located at the inflection point between the two rings.

[0062] In other embodiments, instead of having only one irreversible martensitic segment (e.g., segment 302) for each ring 400, the embolization device 100 may have multiple irreversible martensitic segments for each ring 400.

[0063] In one or more embodiments described herein, the embolization device 100 may optionally include a segment at its proximal end. Figure 5Another example of the embolization device 100 is illustrated. The embolization device 100 is similar to the reference embolization device 100. Figures 3-4 The described embolization device 100, in addition to including a segment 500 at its proximal end, also includes the embolization device 100. (As...) Figure 5 As shown, the embolization device 100 includes a first segment 300, a second segment 302, and a third segment 304, similarly described. However, the embolization device 100 also includes a fourth segment 500 at the proximal end of the elongated member 102. The fourth segment 500 does not change shape in response to body temperature. Figure 6 As shown, after the embolization device 100 is exposed to body temperature, a large portion of the elongated member 102 changes shape to form a three-dimensional structure 112. However, the fourth segment 500 remains straight and does not change its shape. Instead, the fourth segment 500 is configured to change shape in response to force. For example, when the embolization device 100 with the fourth segment 500 is delivered into the aneurysm, or when the fourth segment 500 is pushed out of the catheter 20, the inner wall of the aneurysm or other portions of the embolization device 100 already delivered into the aneurysm can exert force on the fourth segment 500. This will cause the fourth segment 500 to bend. In some embodiments, the fourth segment 500 is martensitic when at room temperature and also martensitic when at body temperature. Furthermore, in some embodiments, the fourth segment 500 is softer than segments with shape memory properties (e.g., the first segment 300, the third segment 304, etc.). Therefore, the fourth segment 500 can bend more easily when an external force is applied. This allows the fourth segment 500 to be formed into any shape depending on the direction and magnitude of the external force. In some cases, the fourth segment 500 can be configured for filling purposes, to fill spaces within body cavities such as aneurysms. In some embodiments, the fourth segment 500 can have a length greater than the length of the preceding ring 400. For example, the fourth segment 500 can have a length equal to 1 (X), 2X, 3X, or 4X the length of the segment forming the preceding ring 400.

[0064] In some embodiments, the fourth segment 500 may be made of the same material as the material used for segment 302 and may have the same mechanical properties as segment 302. In other embodiments, the fourth segment 500 may be softer than segment 302.

[0065] In the illustrated embodiment, the loops 400 of the three-dimensional structure 112 are connected by corresponding inflection points, which allows adjacent loops 400 to form reverse curvature. In other embodiments, adjacent loops 400 of the three-dimensional structure 112 may not form reverse curvature. Furthermore, in other embodiments, instead of having loops, the first three-dimensional structure 112 may have other structural elements that are not loops in shape.

[0066] In some embodiments, the curvature of the rings 400 of the three-dimensional structure 112 may be the same. In other embodiments, one or more of the rings 400 in the three-dimensional structure 112 may differ from the other rings 400. For example, in some embodiments, the three-dimensional structure 112 may have a first ring 400 (with a first curvature) and a second ring 400 adjacent to the first ring 400, wherein the second ring 400 may have a second curvature higher than the first curvature of the first ring 400. In other embodiments, the three-dimensional structure 112 may have a first ring 400 (with a first curvature) and a second ring 400 adjacent to the first ring 400, wherein the second ring 400 may have a second curvature lower than the first curvature of the first ring 400. As used herein, “curvature” may be defined as 1 / R, where R may be the minimum radius of curvature associated with a curve.

[0067] In some embodiments, the three-dimensional structure 112 has at least two rings 400 (e.g., at least two adjacent rings 400) with corresponding ring size variations not exceeding 10%, and preferably not exceeding 5%. For example, in one embodiment, the three-dimensional structure 112 may have rings 400 having the same ring size (e.g., ring width or diameter). In other embodiments, the three-dimensional structure 112 may have rings 400 with corresponding ring size variations exceeding 10%.

[0068] Furthermore, in some embodiments, the ring 400 in the three-dimensional structure 112 has a corresponding ring size that decreases along the length of the elongated member 102 in a direction from the distal to the proximal side. This feature is advantageous because it helps the elongated member 102 form a different infill structure that is smaller than the previous infill structure, thereby allowing subsequent infill structures to fit within the previous infill structure.

[0069] In some embodiments, a first portion of the embolization device 100 may have a first width, and a second portion of the embolization device 100 adjacent to the first portion may have a second width less than the first width. Optionally or additionally, the first portion of the embolization device 100 may have a first thickness, and the second portion of the embolization device 100 may have a second thickness less than the first thickness. In one embodiment, the elongated member 102 may be a braided structure, and the narrower width and / or thickness of the second portion of the embolization device 100 can be achieved by using fewer fiber strands than the number of fiber strands used to form the braid of the first portion. Alternatively, the narrower width (or thickness) of the second portion of the embolization device 100 can be achieved by cutting or grinding away (e.g., using a laser cutter, grinder, etc.) some of the members used to form the second portion. As another alternative, the first and second portions of the embolization device 100 may be formed from separate members with different respective cross-sectional dimensions. In this case, the members may be fixed to each other, for example, using adhesives, welding, fusion, mechanical couplings, etc. It should be noted that the terms "width" and "thickness" can, in some cases, refer to the longer and shorter dimensions of a cross-section (such as a cross-section with a rectangular or elliptical shape). However, the use of either term should not imply that the cross-section has an elongated shape. For example, the width or thickness of a cross-section can refer to the cross-sectional dimensions of a circular, square, hexagonal, pentagonal, etc.

[0070] Furthermore, in some embodiments, the angles of the three-dimensional structure 112 (between adjacent rings 400) may gradually decrease along the length of the elongated member 102 in a direction from distal to proximal. This feature is advantageous because it allows the distal portion of the elongated member 102 to form a first portion of the three-dimensional structure 112 along the periphery of the body cavity, and also allows the proximal portion of the elongated member 102 to form a second portion of the three-dimensional structure 112, which can fit within the first portion of the three-dimensional structure 112. In one embodiment, the first portion of the elongated member 102 may be configured to form a first plurality of rings 400, wherein adjacent rings of the first plurality of rings 400 have a first plurality of angles, and the second portion of the elongated member 102 may be configured to form a second plurality of rings 400, wherein adjacent rings of the second plurality of rings 400 have a second plurality of angles. The first plurality of angles may be the same as each other, and the second plurality of angles may be the same as each other. However, the first plurality of angles may be greater than the second plurality of angles.

[0071] As discussed, in some embodiments, the elongated member 102 may have a gradually decreasing angle between adjacent rings from the distal to the proximal end of the elongated member 102. This allows the elongated member 102 to fill the body cavity from the "outer inward," such that the external space within the body cavity is filled first before the internal space within the aneurysm. In other embodiments, the elongated member 102 may have a gradually increasing angle between adjacent rings from the distal to the proximal end of the elongated member 102. This allows the elongated member 102 to fill the body cavity from the "inner outward," such that the internal space within the body cavity is filled first before the external space within the body cavity.

[0072] In some embodiments, the elongated member 102 of the embolization device 100 may be a braided structure. In one embodiment, the elongated member 102 may be formed from twenty-four braided fiber strands. Alternatively, other numbers of fiber strands may be used to form the elongated member. Furthermore, in some embodiments, the proximal portion of the elongated member 102 may be formed with more strands than the distal portion. In other embodiments, the distal portion of the elongated member 102 may be formed with more strands than the proximal portion, thereby making the distal portion stiffer than the proximal portion.

[0073] In other embodiments, the elongated member 102 of the embolization device 100 may be a coil. In these cases, the elongated member 102 has an initial shape as a coil, and the coil can then be bent to form a desired secondary shape (unfolded shape).

[0074] In another embodiment, the elongated member 102 of the embolization device 100 may be a solid continuous member. In this case, the solid continuous member has a straight initial shape, and the solid continuous member can then be bent to form a desired secondary shape (unfolded shape).

[0075] In one or more embodiments described herein, the length of the elongated member 102 of the embolization device 100 may be any value from 15 cm to 50 cm, or from 25 cm to 45 cm, or from 30 cm to 40 cm. In other embodiments, the length of the elongated member 102 of the embolization device 100 may be less than 15 cm or greater than 40 cm.

[0076] Furthermore, in one or more embodiments described herein, the elongated member 102 of the embolization device 100 can be made of any suitable material. By way of non-limiting example, the elongated member 102 of the embolization device 100 can be made of... Made of AuPt, stainless steel, platinum, other metals, other alloys, or any combination thereof.

[0077] In some embodiments, each preceding portion of the elongated member 102 forms a filling structure that allows subsequent portions of the elongated member 102 to be accommodated. This allows structures of different layers to be progressively delivered into the aneurysm in a nested configuration to fill the aneurysm from its periphery toward its center. In some embodiments, a first portion of the elongated member 102 may have a first set of rings, a second portion of the elongated member 102 adjacent to the first portion may have a second set of rings, a third portion of the elongated member 102 adjacent to the second portion may have a third set of rings, and so on. The first set of rings may have ring widths of the same size or ring widths that decrease in size in the distal to proximal direction. Similarly, the second set of rings may have ring widths of the same size or ring widths that decrease in size in the distal to proximal direction. Furthermore, the third set of rings may have ring widths of the same size or ring widths that decrease in size in the distal to proximal direction. In addition, in some embodiments, the first (i.e., distal) ring in the subsequent portion of the elongated member 102 may have a width smaller than the width of the last (i.e., proximal) ring in the preceding portion of the elongated member 102. Alternatively, in other embodiments, the first (i.e., distal) ring in a subsequent portion of the elongated member 102 may have a width greater than the width of the last (i.e., proximal) ring in a preceding portion of the elongated member 102.

[0078] In one or more embodiments described herein, the embolization device 100 may optionally include a distal ring at its distal end, wherein the distal ring has a diameter that is 75% or less of the diameter of the ring adjacent to the distal ring. As used herein, the term "diameter" of the ring does not necessarily mean that the ring has a circular shape, and the term "diameter" may refer to the width of the ring, which may or may not be circular in shape. For example, the diameter of the ring may refer to the maximum width of the ring in some cases.

[0079] Furthermore, in one or more embodiments described herein, the embolization device 100 may optionally include a distal coil at its distal end. In one embodiment, if the elongated member 102 of the embolization device 100 is formed of a braid, the distal coil may be formed of one or more strands of the braid. In another embodiment, a separate coil may be provided as the distal coil and then attached to the distal end of the elongated member 102.

[0080] Furthermore, in one or more embodiments described herein, the embolization device 100 may optionally include a proximal coil at its proximal end. In one embodiment, if the elongated member 102 of the embolization device 100 is formed of a braid, the proximal coil may be formed from one or more strands of the braid. In another embodiment, a separate coil may be provided as the proximal coil and then attached to the proximal end of the elongated member 102. The proximal coil is advantageous because it can provide a stiffness transition from the embolization device 100 to the shaft 30.

[0081] Furthermore, in one or more embodiments described herein, the proximal portion of the embolization device 100 may have a different stiffness (e.g., bending stiffness and / or axial stiffness) than the distal portion of the embolization device 100. In some embodiments, the proximal portion of the embolization device 100 may have a column strength different from that of the distal portion. For example, the column strength of the proximal portion of the embolization device 100 may be higher than that of the distal portion. This is advantageous because it allows the embolization device 100 to be pushed distally within the conduit 20 without buckling. The relative difference in column strength and / or stiffness can be achieved using metallurgical heat treatment conditions, by varying the cross-sectional dimensions, and / or by changing the number of strands along the length of the elongated member 102 in the braided structure.

[0082] Furthermore, in one or more embodiments described herein, if the elongated member 102 is a braided structure, the braiding angle of the strands along the length of member 102 can be varied to change the stiffness along the length of elongated member 102. For example, in some embodiments, the proximal and distal portions of elongated member 102 may have the same number of strands, but the braiding angle of the strands in the proximal portion (e.g., the angle formed by the strands relative to the longitudinal axis of member 102) may be greater than the braiding angle of the strands in the distal portion, thereby making the proximal portion of elongated member 102 stiffer than the distal portion. In other embodiments, the braiding angle of the strands in the distal portion of elongated member 102 may be greater than the braiding angle of the strands in the proximal portion, thereby making the second portion of elongated member 102 softer than the first portion. Furthermore, in some embodiments, the braiding angle of the strands along the length of member 102 may vary gradually.

[0083] Furthermore, in some embodiments, the three-dimensional structure includes a first plurality of rings 400, wherein the ring width, ring curvature, braiding width, braiding angle, or any combination thereof of the respective rings in the first plurality of rings 400 increases or decreases along the length of the elongated member 102 forming the three-dimensional structure 112.

[0084] Furthermore, in some embodiments, the three-dimensional structure 112 includes a plurality of rings 400, wherein the angle between adjacent rings among the plurality of rings 400 increases or decreases along the length of the elongated member 102 forming the three-dimensional structure 112.

[0085] Furthermore, it should be noted that the embolization device 100 is not limited to the examples described herein, and the embolization device 100 may have other configurations in other embodiments. For example, in other embodiments, the embolization device 100 may be configured to form other three-dimensional structures different from those described herein.

[0086] In another embodiment, the embolization device 100 is not configured to fill the body cavity from the periphery toward the center, nor is it configured to fill the body cavity from the center toward the periphery. Instead, the embolization device may be configured to fill the body cavity from one side toward the opposite side. Alternatively, the embolization device may be configured to fill the body cavity in a random manner.

[0087] Various techniques can be used to form the embolic device 100. In some embodiments, the elongated member 102 may be wound around one or more mandrels to form a desired shape. The mandrel may include a plurality of posts configured to allow the elongated member 102 to be wound around it. The dimensions of the posts will determine the ring size to be formed. Furthermore, the relative orientation of the posts will determine the relative angles between the rings to be formed. After the elongated member 102 is wound around the mandrel, the elongated member 102 may be chemically treated and / or heat-treated to achieve the unfolded shape of the elongated member 102 and / or to provide different mechanical properties to different portions of the elongated member 102.

[0088] In some embodiments, controlled heating and / or localized heating can be performed such that different segments along the length of the elongated member 102 will have different phase transformation temperatures. This can be achieved, for example, by laser heating. Specifically, first heat treatment conditions can be applied along the length of the elongated member 102 to a first set of segments (e.g., segments 302, 412, etc.) such that their transformation temperatures are above body temperature (37°C). Therefore, when the device is deployed to the treatment site, these segments will retain their martensitic phase. Since there is no martensitic-to-austenitic phase transformation, these segments are considered irreversible martensitic segments. In contrast, second heat treatment conditions can be applied to a second set of segments (e.g., segments 300, 304, 410, 414, etc.) such that their transformation temperatures are below body temperature (37°C). When the embolization device 100 is deployed to the treatment site, these segments will have a martensitic-to-austenitic phase transformation. These segments are considered reversible martensitic segments. Thermally induced martensite generally appears in the form of twinned martensite, and the material deforms in the martensitic state in response to the material reaching the transformation temperature. The twinned martensite structure can be changed into a detwinned structure.

[0089] In other embodiments, deformation strain control can be applied to different segments along the length of the elongated member 102. Specifically, a first strain condition can be applied to a first group of segments (e.g., segments 302, 412, etc.) such that the strain exceeds the recoverable limit of its martensitic phase, and therefore the martensitic phase cannot transform into the austenitic phase when the embolization device is deployed to the treatment site. These segments always retain the martensitic phase and are therefore considered irreversible martensitic segments. On the other hand, a second strain condition can be applied to a second group of segments (e.g., segments 300, 304, 410, 414, etc.) such that the strain level is within its recoverable limit, and therefore the martensitic phase will transform into the austenitic phase when the embolization device 100 is deployed to the treatment site. These segments are therefore considered reversible martensitic segments.

[0090] In other embodiments, portions of the elongated member 102 may be covered with a shielding material, while other portions of the elongated member 102 may be chemically treated and / or heat-treated. This allows for the formation of different portions of the elongated member 102 with different mechanical properties. For example, this technique can be used to create irreversible and reversible martensitic segments along the length of the elongated member 102.

[0091] In another embodiment, a combination of the above techniques can be used to generate irreversible martensitic segments and reversible martensitic segments along the length of the elongated member 102.

[0092] In other embodiments, other techniques for forming elongated components may be used to form the embolization device 100.

[0093] The elongated member 102 has been formed to have an unfolded shape (e.g., similar to...). Figure 4 and Figure 6 (as shown in the example) and having irreversible martensitic segments (e.g., segments 302, 412, etc.) and reversible martensitic segments (e.g., segments 300, 304, 410, 414, etc.) along the length of the elongated member 102, the elongated member 102 can be further processed to form a delivery shape (e.g., similar to...). Figure 3 and Figure 5 (Example shown). In some embodiments, this can be achieved using thermal cycling. For example, an elongated member 102 (already formed to have an unfolded shape) can be subjected to repeated heating and cooling while the elongated member 102 is positioned in the desired delivery shape to be formed. In one technique, the elongated member 102 can be stretched into a straight profile while being subjected to repeated heating and cooling. In some embodiments, heating can be performed to heat the elongated member 102 to a temperature above 80°C or more preferably above 90°C (e.g., 100°C) or more preferably above 100°C. Furthermore, in some embodiments, cooling can be performed to cool the elongated member 102 to a temperature below 10°C or more preferably below 0°C or more preferably below -10°C. This technique can be used to implement the embolization device 100 such that the embolization device 100 has a first shape (delivery shape) when it is at room temperature and a second shape (unfolded shape) when it is at body temperature (e.g., when the embolization device 100 unfolds in a patient). Figure 7 This is a stress-strain diagram, which specifically illustrates the effect of thermal cycling. As can be seen from the diagram, when the elongated member 102 is subjected to heating and cooling, thermal stress is applied to the elongated member 102, causing a shift in the stress-strain curve of the elongated member 102. If heating and cooling are repeated for additional cycles, additional thermal stress is applied to the elongated member 102, causing a further shift in the stress-strain curve.

[0094] It should be noted that the transition temperature of the plugging device 100 from the delivery shape to the unfolded shape can be selectively configured using the material composition and / or manufacturing process. For example, the austenitic finishing temperature can be selected for the manufacturing process of a given material so that the final product will have the desired transition temperature.

[0095] Figures 8A-8B The diagram illustrates the use of Figure 1A method for treating aneurysm 700 using medical device 10. When using medical device 10, catheter 20 is first inserted into the patient's blood vessel 702 through an incision. Then catheter 20 is advanced distally until the distal end 22 of catheter 20 is located at aneurysm 700.

[0096] In some embodiments, catheter 20 may be maneuverable. For example, catheter 20 may include one or more maneuver wires configured to maneuver the distal end 22 of catheter 20 in one or more directions. In other embodiments, catheter 20 may not be maneuverable. Instead, a guidewire may be used first to approach the target site. Catheter 20 may then be positioned on the guidewire and advanced distally using the guidewire. In this case, catheter 20 may include a separate channel for receiving the guidewire.

[0097] After the distal end 22 of the catheter 20 is desirably placed, the shaft 30 (as shown) Figure 1 (As shown) is then advanced to push the embolization device 100 distally until the first distal portion of the embolization device 100 is located outside the catheter 20. Figure 8A When residing inside the catheter 20 at room temperature, the embolization device 100 has a straight profile. This straight profile is due to the embolization device 100 being at room temperature, not due to any mechanical straightening applied by the catheter 20. Therefore, the embolization device 100 can be more easily advanced distally. This feature also allows for the delivery of longer embolization devices 100 if desired. As shown, when the first portion of the elongated member 102 is unrestricted outside the catheter 20, the first portion of the elongated member 102 changes its relatively straight shape in response to body temperature to form the first portion of the three-dimensional structure 112. Specifically, reversible martensitic segments along the elongated member 102 (e.g., segments 300, 304, 410, 414, etc.) transform into austenitic segments in response to body temperature. These austenitic segments have curved profiles to provide a delivery shape for the unfolded portion of the elongated member 102. Irreversible martensitic segments (e.g., segments 302, 412, etc.) along the elongated member 102 remain in the martensitic phase. These irreversible martensitic segments are softer than reversible martensitic segments and therefore more readily flex in response to force. Thus, when the first portion of the three-dimensional structure 112 is delivered into the aneurysm, the rings of the three-dimensional structure 112 are pressed against the wall of the aneurysm, which applies force to the irreversible martensitic segments. These segments flex in response to force, thereby allowing the delivered first portion of the three-dimensional structure 112 to better conform to the shape of the aneurysm 700.

[0098] In the illustrated example, the first portion of the three-dimensional structure 112 has a shape corresponding to the inner wall of the aneurysm. Figure 8AThe first portion of the three-dimensional structure 112, schematically represented by the dashed lines, provides a framework defining a cavity 118 for receiving a subsequent portion of the embolization device 100 to be delivered. As shown, the first portion of the three-dimensional structure 112 also provides a stent across the neck 704 of the aneurysm 700, which helps to receive a subsequent portion of the elongated member 102 of the embolization device 100 to be delivered into the cavity 118.

[0099] Next, shaft 30 can be further advanced to push the subsequent portion of the embolization device 100 out of catheter 20. Figure 8B As shown in the figure, when the subsequent portion is unrestricted outside the catheter 20, it forms a second portion of the three-dimensional structure 112. The second portion of the three-dimensional structure 112 has a shape that allows it to fill at least some of the spaces in the cavity 118 defined by the first portion of the three-dimensional structure 112. As shown in the figure, the stent provided by the first portion of the three-dimensional structure 112 across the neck 704 of the aneurysm prevents the second portion of the three-dimensional structure 112 from escaping or detaching from the cavity 118 of the first portion of the three-dimensional structure 112 and the aneurysm.

[0100] Similar to the discussion of the first portion of the three-dimensional structure 112, for the second portion of the three-dimensional structure 112, the reversible martensitic segments along the elongated member 102 transform into austenitic segments in response to body temperature. These austenitic segments have curved profiles to provide a delivery shape for the unfolded portion of the elongated member 102. On the other hand, the irreversible martensitic segments along the elongated member 102 remain in the martensitic phase. These irreversible martensitic segments are softer than the reversible martensitic segments and therefore they are more prone to bending in response to force. Thus, when the second portion of the three-dimensional structure 112 is delivered into the aneurysm, the rings of the three-dimensional structure 112 are pressed against the wall of the aneurysm (or against the first portion of the three-dimensional structure 112), which applies force to the irreversible martensitic segments. These segments bend in response to force, thereby allowing the delivered second portion of the three-dimensional structure 112 to better conform to the shape of the cavity to be filled.

[0101] In some embodiments, the distal end of the shaft 30 is abutted against the proximal end of the elongated member 102 and is not mechanically attached to the proximal end of the elongated member 102. In these cases, once the proximal end of the elongated member 102 is expelled from the catheter 20, the elongated member 102 is disconnected from the remainder of the medical device 10. In other embodiments, the distal end of the shaft 30 may be mechanically connected to the proximal end of the elongated member 102, for example, via a mechanical connector operable to disengage the proximal end of the elongated member 102 from the shaft 30. In yet another embodiment, the distal end of the shaft 30 may be mechanically connected to the proximal end of the elongated member 102 via a detachable link (e.g., a link that can disassemble in response to the application of an electric current). Mechanical connectors and detachable links are well known in the art and will therefore not be described in further detail.

[0102] As illustrated in the above embodiments, the embolization device 100 is advantageous because the relatively soft individual discrete irreversible martensitic segments provide some flexibility to the embolization device 100, allowing it to bend easily in response to force. While some discrete portions of the embolization device 100 (the irreversible martensitic segments) can bend more easily, most other portions of the embolization device 100 (i.e., the reversible martensitic segments) remain relatively stiff compared to the irreversible martensitic segments, allowing the shape of most portions of the embolization device 100 to remain within the body cavity. Furthermore, the embolization device 100 is also advantageous because it has a relatively straight delivery shape within the catheter 20 compared to its unfolded shape. This allows the embolization device 100 to be easily advanced distally relative to the catheter 20 without the use of significant axial thrust and reduces the risk of buckling of the embolization device 100 within the catheter 20.

[0103] In some embodiments, the plurality of embolization devices 100 may have different corresponding lengths. In these cases, before selecting one of the embolization devices 100 for treating the aneurysm, the physician can measure the size of the aneurysm to be treated. For example, the physician can perform measurements using one or more images of the aneurysm to determine its size. This size may be the cross-sectional dimensions of the aneurysm, the cross-sectional area of ​​the aneurysm, the volume of the aneurysm, etc. After the size of the aneurysm is determined, one of the embolization devices 100 can then be selected based on the size of the aneurysm. For example, a longer embolization device 100 may be selected to occlude a larger aneurysm.

[0104] Figure 9A method 800 for occluding a body cavity is illustrated. Method 800 is performed by an embolization device having an elongated member comprising a first segment, a second segment, and a third segment, wherein the second segment is located between the first and third segments. Method 800 includes: in response to body temperature, performing a first shape change through the first segment of the elongated member (item 802); in response to force, performing a second shape change through the second segment of the elongated member (item 804); and in response to body temperature, performing a third shape change through the third segment of the elongated member (item 806).

[0105] In some embodiments, the embolization device in method 800 may be the embolization device 100 described herein.

[0106] Optionally, in this method, the first segment is martensite when at room temperature and austenite when at body temperature; and wherein the second segment is martensite when at room temperature and also martensite when at body temperature.

[0107] Optionally, in this method, in response to body temperature, the first segment forms a first portion of the ring, and the third segment forms a second portion of the ring.

[0108] Optionally, in this method, in response to body temperature, the first segment forms a first ring, and the third segment forms a second ring.

[0109] Optionally, in this method, the first segment has a first length, the second segment has a second length, and the third segment has a third length; and wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0110] Optionally, in this method, the second length of the second segment located between the first segment and the third segment is less than 50% of the first length of the first segment, and also less than 50% of the third length of the third segment.

[0111] Optionally, in this method, the elongated member has a distal end and a proximal end opposite to the distal end, and the embolization device further includes a fourth segment containing the proximal end; and the fourth segment is martensitic when at room temperature, and is also martensitic when at body temperature.

[0112] Optionally, in this method, the three-dimensional structure comprises multiple rings, wherein the first segment, the second segment, and the third segment are parts of one of these rings.

[0113] Optionally, in this method, the elongated member further includes a fourth segment, a fifth segment, and a sixth segment, which are portions of another ring among these rings; wherein the fifth segment is located between the fourth and sixth segments; wherein the fourth and sixth segments are martensitic at room temperature and austenitic at body temperature; and wherein the fifth segment is martensitic at room temperature and also martensitic at body temperature.

[0114] The following items are exemplary features of the embodiments described herein. Each item may be the embodiment itself or may be part of an embodiment. In one embodiment, one or more items described below may be combined with other items.

[0115] Item 1: An embolization device for placement in a body cavity, comprising: an elongated member having a linear configuration at room temperature, the elongated member being configured to form a first three-dimensional structure in response to body temperature; wherein the elongated member includes a first segment, a second segment, and a third segment, the second segment being located between the first segment and the third segment; wherein the first segment and the third segment are configured to change their respective shapes in response to body temperature; and wherein the second segment located between the first segment and the third segment has a shape independent of body temperature.

[0116] Item 2: In response to body temperature, the first segment is configured to form the first part of the loop, and the third segment is configured to form the second part of the loop.

[0117] Item 3: In response to body temperature, the first segment is configured to form the first ring, and the third segment is configured to form the second ring.

[0118] Item 4: The first segment has a first length, the second segment has a second length, and the third segment has a third length; and wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0119] Item 5: The second length of the second segment located between the first and third segments is less than 50% of the first length of the first segment and also less than 50% of the third length of the third segment.

[0120] Item 6: The elongated member has a distal end and a proximal end opposite to the distal end, and wherein the embolization device further includes a fourth segment containing the proximal end; and wherein the fourth segment is martensitic at room temperature and also martensitic at body temperature.

[0121] Item 7: When the first segment is at room temperature, the first segment is martensite, and when the first segment is at body temperature, the first segment is austenite.

[0122] Item 8: The second segment is martensitic when at room temperature, and is martensitic when at body temperature.

[0123] Item 9: The three-dimensional structure comprises multiple rings, wherein the first segment, the second segment, and the third segment are parts of one of these rings.

[0124] Item 10: The elongated member further includes a fourth segment, a fifth segment, and a sixth segment, which are part of another ring among these rings; wherein the fifth segment is located between the fourth segment and the sixth segment; wherein the fourth segment and the sixth segment are configured to change their respective shapes in response to body temperature; and wherein the fifth segment located between the fourth segment and the sixth segment has a shape independent of body temperature.

[0125] Item 11: An embolization device for placement in a body cavity, comprising: an elongated member having a linear configuration at room temperature, the elongated member being configured to form a first three-dimensional structure in response to body temperature; wherein the elongated member includes a first segment, a second segment, and a third segment, the second segment being located between the first segment and the third segment; wherein the first segment is martensitic at room temperature and austenitic at body temperature; and wherein the second segment is martensitic at room temperature and also martensitic at body temperature.

[0126] Item 12: In response to body temperature, the first segment is configured to form the first part of the loop, and the third segment is configured to form the second part of the loop.

[0127] Item 13: In response to body temperature, the first segment is configured to form the first ring, and the third segment is configured to form the second ring.

[0128] Item 14: The first segment has a first length, the second segment has a second length, and the third segment has a third length; and wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0129] Item 15: The second length of the second segment located between the first segment and the third segment is less than 50% of the first length of the first segment, and is also less than 50% of the third length of the third segment.

[0130] Item 16: The elongated member has a distal end and a proximal end opposite to the distal end, and wherein the embolization device further includes a fourth segment containing the proximal end; and wherein the fourth segment is martensitic when at room temperature, and is also martensitic when the fourth segment is at body temperature.

[0131] Item 17: The three-dimensional structure comprises multiple rings, wherein the first segment, the second segment, and the third segment are parts of one of these rings.

[0132] Item 18: The elongated member further includes a fourth segment, a fifth segment, and a sixth segment, which are part of another ring among these rings; wherein the fifth segment is located between the fourth and sixth segments; wherein the fourth and sixth segments are martensitic at room temperature and austenitic at body temperature; and wherein the fifth segment is martensitic at room temperature and also martensitic at body temperature.

[0133] Item 19: A method for occluding a body cavity by means of an embolization device having an elongated member comprising a first segment, a second segment, and a third segment, wherein the second segment is located between the first segment and the third segment, the method comprising: performing a first shape change through the first segment of the elongated member in response to body temperature; performing a second shape change through the second segment of the elongated member in response to force; and performing a third shape change through the third segment of the elongated member in response to body temperature.

[0134] Item 20: The first segment is martensite at room temperature and austenite at body temperature; and wherein the second segment is martensite at room temperature and also martensite at body temperature.

[0135] Item 21: In response to body temperature, the first segment forms the first part of the loop, and the third segment forms the second part of the loop.

[0136] Item 22: In response to body temperature, the first segment forms the first loop, and the third segment forms the second loop.

[0137] Item 23: The first segment has a first length, the second segment has a second length, and the third segment has a third length; and wherein the second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

[0138] Item 24: The second length of the second segment located between the first segment and the third segment is less than 50% of the first length of the first segment, and is also less than 50% of the third length of the third segment.

[0139] Item 25: The elongated member has a distal end and a proximal end opposite to the distal end, and wherein the embolization device further includes a fourth segment containing the proximal end; and wherein the fourth segment is martensitic when at room temperature, and is also martensitic when the fourth segment is at body temperature.

[0140] Item 26: The three-dimensional structure comprises multiple rings, wherein the first segment, the second segment, and the third segment are parts of one of these rings.

[0141] Item 27: The elongated member further includes a fourth segment, a fifth segment, and a sixth segment, which are part of another ring among these rings; wherein the fifth segment is located between the fourth and sixth segments; wherein the fourth and sixth segments are martensitic at room temperature and austenitic at body temperature; and wherein the fifth segment is martensitic at room temperature and also martensitic at body temperature.

Claims

1. An embolization device for placement in a body cavity, the embolization device comprising: An elongated member having a straight structure at room temperature, the elongated member being configured to form a three-dimensional structure in response to body temperature in the temperature range of 35°C to 37.8°C or 35°C to 37.2°C. The elongated component includes a first segment, a second segment, and a third segment, wherein the second segment is located between the first segment and the third segment. Wherein, when the first segment is at room temperature, the first segment is martensitic, and when the first segment is at body temperature, the first segment is austenitic. Wherein, when the second segment is at room temperature, the second segment is martensitic, and when the second segment is at body temperature, the second segment is also martensitic; and Specifically, when the third segment is at room temperature, the third segment is martensitic, and when the third segment is at body temperature, the third segment is austenitic. Wherein, the second segment is an irreversible martensitic segment, and the first segment and the third segment are reversible martensitic segments, wherein the irreversible martensitic segment is softer than the reversible martensitic segment.

2. The embolization device according to claim 1, wherein, In response to the body temperature, the first segment is configured to form a first portion of the ring, and the third segment is configured to form a second portion of the ring.

3. The embolization device according to claim 1, wherein, In response to the body temperature, the first segment is configured to form a first ring, and the third segment is configured to form a second ring.

4. The embolization device according to claim 1, in, The first segment has a first length, the second segment has a second length, and the third segment has a third length. The second length of the second segment is shorter than the first length of the first segment and also shorter than the third length of the third segment.

5. The embolization device according to claim 4, wherein, The second length of the second segment, located between the first segment and the third segment, is less than 50% of the first length of the first segment and also less than 50% of the third length of the third segment.

6. The embolization device according to any one of claims 1-5, in, The elongated member has a distal end and a proximal end opposite to the distal end. The embolization device further includes a fourth segment comprising the proximal end, and The fourth segment is martensitic at room temperature and is also martensitic at body temperature.

7. The embolization device according to any one of claims 1-6, wherein, The three-dimensional structure includes a plurality of rings, wherein the first segment, the second segment, and the third segment comprise corresponding portions of a single ring among the plurality of rings.

8. The embolization device according to claim 7, in, The elongated member further includes a fourth segment, a fifth segment, and a sixth segment, wherein the fourth segment, the fifth segment, and the sixth segment comprise corresponding portions of another ring among the plurality of rings. The fifth segment is located between the fourth segment and the sixth segment. Specifically, when the fourth and sixth segments are at room temperature, they are martensitic, and when the fourth and sixth segments are at body temperature, they are austenitic. Specifically, when the fifth segment is at room temperature, the fifth segment is martensitic, and when the fifth segment is at body temperature, the fifth segment is also martensitic.

9. The embolization device according to claim 1, wherein, The elongated component further includes a fourth segment, a fifth segment, and a sixth segment. The fifth segment is located between the fourth segment and the sixth segment. The fourth and sixth segments are configured to change their respective shapes in response to body temperature. The fifth segment, located between the fourth and sixth segments, has a shape independent of body temperature.

10. The embolization device according to claim 1, wherein, The first segment and the third segment are configured to change their respective shapes in response to the body temperature; and The second segment, located between the first segment and the third segment, has a shape independent of the body temperature.

11. The embolization device according to claim 1, wherein, The second segment is located between the two rings.

12. The embolization device according to claim 1, wherein, The second segment is located at the inflection point between the two loops.

13. The embolization device according to claim 1, wherein, The elongated member is a braided structure, and the braiding angle along the length of the elongated member is variable.

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