In-vivo indwelling device

Abstract

To provide an in-vivo indwelling device that is capable of promoting early thrombosis at a target site such as the interior of an aneurysm and is unlikely to cause damage even when brought into contact with another object. An in-vivo indwelling device (1) comprises a coil (10) around which a wire material (11) is wound and which has a longitudinal axis direction (x), and a fiber (20) disposed in the lumen of the coil (10). The fiber (20) partially extends to the outside of the coil (10). On the outside of the coil (10), the fiber (20) has a branch point (60) at which the fiber (20) branches.

Description

Intravital device

[0001] The present invention relates to an in-vivo indwelling device to be placed in a body lumen such as a blood vessel.

[0002] Endovascular treatment is one of the treatments for vascular lesions such as head and neck aneurysms, arteriovenous malformations, arteriovenous fistulas, pulmonary vascular malformations, renal vascular malformations, renal artery aneurysms, and abdominal aneurysms. Embolization is used to prevent rupture of aneurysms and other aneurysms by placing an in-vivo indwelling device with an embolization coil at the target site, such as inside the aneurysm, to promote thrombosis.

[0003] For example, U.S. Patent No. 6,275,999 discloses a vasoocclusive device comprising an outer helically wound primary coil having a first end and a second end and defining a lumen between the first end and the second end, and a stretch-resistant member extending through the lumen and fixedly attached to the primary coil at at least two locations, the stretch-resistant member comprising a plurality of fibers. U.S. Patent No. 6,275,999 discloses a vasoocclusive implant comprising, in combination, an elongate core member, a first fibrous member attached to the elongate core member, and a second fibrous member attached to the elongate core member, the elongate core member having a proximal end and a distal end, the first fibrous member comprising a first polymeric material, and the second fibrous member comprising a second polymeric material different from the first polymeric material. Patent Document 3 discloses an embolic coil comprising an elongate core element formed of a shape memory material treated to form a memorized second coil shape, and an elongate outer element wound around the elongate core element to form a first coil shape of the embolic coil, and a plurality of fibers extending from the embolic coil. Patent Document 4 discloses an occlusion device comprising a coiled fiber comprising a first bioabsorbable material composition, and a plurality of intersecting microfibers attached to at least a portion of the coiled fiber, extending radially from the outer diameter of the coiled fiber, and comprising a second bioabsorbable material composition.

[0004] Japanese Patent Laid-Open No. 10-000198 Special Publication No. 2002-502659 Special Publication No. 2006-528512 Japanese Patent Laid-Open No. 2022-159143

[0005] The in-vivo indwelling devices described in Patent Documents 1 to 4 have room for improvement in terms of preventing early thrombosis at the target site, such as within an aneurysm, after the in-vivo indwelling device is placed at the target site. Furthermore, the in-vivo indwelling devices described in Patent Documents 1 to 4 have the risk of damaging the luminal wall of the biological lumen, such as the inner wall of an aneurysm, by coming into contact with the distal end of the in-vivo indwelling device when transporting the in-vivo indwelling device to the target site, and therefore also have room for improvement in terms of improving safety.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an in-vivo indwelling device that can promote early thrombosis at a target site such as within a lump and that is less likely to cause damage even when it comes into contact with other objects.

[0007] The following are embodiments of the present invention that have solved the above-mentioned problems. [1] An in-vivo indwelling device comprising: a coil wound with a wire and having a longitudinal axis direction; and fibers disposed in the lumen of the coil, wherein a portion of the fibers extends outside the coil, and the fibers have a branch point outside the coil where the fibers branch. [2] The in-vivo indwelling device according to [1], comprising a fiber bundle containing the fibers, the proximal end of which is disposed in the lumen of the coil and the distal end of which is exposed from the coil. [3] The in-vivo indwelling device according to [2], wherein 30% or more of all the fibers constituting the fiber bundle have the branch point. [4] The in-vivo indwelling device according to [2] or [3], wherein the fiber bundle has a central region that is an area surrounded by a circle whose diameter is half the diameter of the circumscribing circle of the fiber bundle and whose center is the centroid of the lumen of the coil as seen from the distal end of the coil, and a peripheral region that is an area obtained by excluding the central region from the circumscribing circle of the fiber bundle, and the fiber bundle has a portion in which the fiber density of the fiber bundle in the central region is higher than the fiber density of the fiber bundle in the peripheral region. [5] The in-vivo indwelling device according to any of [2] to [4], wherein the fiber bundle has a fixed portion in which the relative position of the fiber bundle and the coil is fixed, and a free portion in which the relative position of the fiber bundle and the coil is not fixed, and the number of branch points located in the portion of the free portion that is exposed from the coil is greater than the number of branch points located in the fixed portion. [6] The in-vivo indwelling device according to [5], wherein the diameter of a circumscribing circle of the fiber bundle at the free portion in a cross section perpendicular to the longitudinal axis direction of the coil is larger than the inner diameter of the distal end of the coil. [7] The in-vivo indwelling device according to any of [2] to [6], further comprising an elongation-resistant member disposed in the lumen of the coil, wherein the fiber bundle has a bundling portion where proximal ends of a plurality of the fibers are bundled and fixed, and the bundling portion and the elongation-resistant member are connected. [8] The in-vivo indwelling device according to [7], wherein the bundling portion has a resin tube, and the proximal ends of a plurality of the fibers are disposed in the lumen of the resin tube.[9] The in-vivo indwelling device according to [5], wherein the length of the fixed portion in the longitudinal axis direction of the coil is longer than the average length of the fibers exposed from the coil in the free portion in the longitudinal axis direction of the coil.

[10] The in-vivo indwelling device according to any of [1] to [9], wherein the coil has a reduced diameter portion at a distal end of the coil, where the inner diameter of the coil is reduced.

[11] The in-vivo indwelling device according to

[10] , wherein the reduced diameter portion includes a proximal reduced diameter portion including a proximal end of the reduced diameter portion and a distal reduced diameter portion located distal to the distal end of the proximal reduced diameter portion, and wherein the average inner diameter of the proximal reduced diameter portion is smaller than the average inner diameter of the distal reduced diameter portion.

[12] The in-vivo indwelling device according to

[10] or

[11] , wherein the fiber bundle has a fixed portion where the relative position of the fiber bundle and the coil is fixed, and a free portion where the relative position of the fiber bundle and the coil is not fixed, and the length of the fibers exposed from the coil in the free portion in the longitudinal axis direction of the coil is longer than the length of the tapered portion in the longitudinal axis direction of the coil.

[13] The in-vivo indwelling device according to any of [1] to

[12] , wherein the fibers contain collagen.

[0008] According to the in-vivo indwelling device of the present invention, the fibers are disposed in the lumen of the coil, with a portion extending outside the coil, and the fibers have branching points outside the coil, thereby increasing the specific surface area of ​​the fibers. As a result, thrombus tends to adhere to the exposed fibers from the coil, promoting thrombus formation, and the distal end of the in-vivo indwelling device is covered with the fibers, making it less likely to injure other objects.

[0009] Fig. 1 shows a side view (partial cross-sectional view) along the longitudinal axis direction of an in-vivo indwelling device in one embodiment of the present invention. Fig. 2 shows an enlarged view of fibers possessed by the in-vivo indwelling device shown in Fig. 1. Fig. 3 shows a view of the fiber bundle possessed by the in-vivo indwelling device shown in Fig. 1, as seen from the distal end. Fig. 4 shows a side view (partial cross-sectional view) along the longitudinal axis direction of an in-vivo indwelling device in another embodiment of the present invention.

[0010] The present invention will be described in more detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification and other drawings. The dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to helping understand the features of the present invention.

[0011] Fig. 1 is a side view (partial cross-sectional view) taken along the longitudinal axis direction x of an in-vivo indwelling device 1 according to an embodiment of the present invention, Fig. 2 is an enlarged view of a fiber 20 contained in the in-vivo indwelling device 1, and Fig. 3 is a view of a fiber bundle 30 contained in the in-vivo indwelling device 1 as viewed from the distal end. Also, Fig. 4 is a side view (partial cross-sectional view) taken along the longitudinal axis direction x of an in-vivo indwelling device 1 according to another embodiment of the present invention.

[0012] As shown in Figures 1 and 4, the in-vivo indwelling device 1 includes a coil 10 around which a wire 11 is wound and which has a longitudinal axis direction x, and a fiber 20 disposed in the lumen of the coil 10.

[0013] In the present invention, the proximal side refers to the side closer to the user with respect to the longitudinal axis direction x of the coil 10, and the distal side refers to the side opposite the proximal side, i.e., the side (lesion side) where treatment is performed by the in-vivo indwelling device 1. The longitudinal axis direction x of the coil 10 may also be referred to as the extension direction of the coil 10. The longitudinal axis direction x of the coil 10 can also be referred to as the near-to-far direction of the coil 10.

[0014] Furthermore, a radial direction y and a circumferential direction z are defined as directions orthogonal to the longitudinal axis direction x. The radial direction y is a direction perpendicular to the longitudinal axis direction x, and is a direction connecting the centroid of the outer edge of the coil 10 and a point on the outer edge in a cross section perpendicular to the longitudinal axis direction x. The circumferential direction z is a direction along the outer edge of the coil 10 in a cross section perpendicular to the longitudinal axis direction x.

[0015] The coil 10 is formed by winding a wire 11. Preferably, the coil 10 has a primary shape formed by winding the wire 11, and a secondary shape formed by winding a coil portion of the primary shape. The primary shape of the coil 10 is also referred to as a primary coil, and is preferably formed by winding the wire 11 in a spiral shape. The secondary shape of the coil 10 is also referred to as a secondary coil, and is preferably formed by further forming the primary coil into an arc shape, a wave shape, a serpentine shape, a zigzag shape, a spiral shape (also called a two-dimensional spiral shape or spiral shape), a ball shape, a box shape, or any other randomly curved shape without a loop.

[0016] The material constituting the wire 11 forming the coil 10 is preferably biocompatible and flexible. Examples of materials constituting the wire 11 include metals such as platinum, gold, titanium, tungsten, alloys thereof, stainless steel, and combinations thereof. In particular, the material constituting the wire 11 is preferably a platinum-tungsten alloy. By using a platinum-tungsten alloy as the material constituting the wire 11, the coil 10 has excellent flexibility, making it easier to fill a target site, such as the inside of a lump, with the coil 10.

[0017] The cross-sectional shape of the wire 11 forming the coil 10 perpendicular to the longitudinal axis direction x may be circular, oval, polygonal, or a combination thereof. Note that the oval shape includes an ellipse, an egg shape, and a rounded rectangle. The outer diameter of the wire 11 forming the coil 10 may be, for example, 25 μm or more, 30 μm or more, or 35 μm or more, or 120 μm or less, 100 μm or less, or 70 μm or less.

[0018] The wire 11 forming the coil 10 has a distal end and a proximal end. The wire 11 may be composed of a single linear member from the distal end to the proximal end, or may be composed of multiple linear members connected to each other in the longitudinal axis direction x.

[0019] The coil 10 may be a single-layer coil having one layer, or a multi-layer coil having multiple layers. Also, the coil 10 may have a single layer in a portion of the longitudinal axis direction x of the coil 10 and a multi-layer in the remaining portion.

[0020] The density of the coil 10, i.e., the winding spacing of the wire 11 forming the coil 10, is not particularly limited, and examples include close winding, pitch winding, and a combination thereof. In the coil 10, adjacent wire rods 11 may be in contact with each other in a portion of the longitudinal axis direction x, or adjacent wire rods 11 may be in contact with each other over the entire longitudinal axis direction x. Note that a state in which adjacent wire rods 11 are in contact with each other in the longitudinal axis direction x of the coil 10 is called close winding, and a state in which they are not in contact is called pitch winding. A state in which adjacent wire rods 11 are not in contact with each other in the longitudinal axis direction x of the coil 10 refers to a state in which there is a gap between adjacent wire rods 11 in the longitudinal axis direction x of the coil 10.

[0021] The cross-sectional shape of the coil 10 perpendicular to the longitudinal axis direction x may be circular, elliptical, polygonal, or a combination thereof. The maximum and minimum outer diameters of the coil 10 can be selected appropriately depending on the size of the aneurysm, the procedure, etc. For example, the minimum outer diameter of the coil 10 may be 150 μm or more, 180 μm or more, or 200 μm or more, and the maximum outer diameter of the coil 10 may be 500 μm or less, 380 μm or less, or 350 μm or less.

[0022] 1 and 4, a portion of the fiber 20 is disposed within the lumen of the coil 10. The material constituting the fiber 20 may be collagen, polyester such as polyethylene terephthalate, polypropylene, polyurethane, PLA / PGA polymer, or a combination thereof.

[0023] In particular, it is preferable that the fibers 20 contain collagen. That is, it is preferable that the in-vivo indwelling device 1 has collagen fibers. When the fibers 20 contain collagen, the binding between the fibers 20 and thrombi can be enhanced. As a result, thrombi are more likely to form in the in-vivo indwelling device 1, and early thrombosis can be more easily promoted.

[0024] The outer diameter of the fiber 20 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. By setting the lower limit of the outer diameter of the fiber 20 within the above range, thrombi can adhere more easily to the fiber 20, thereby promoting thrombus formation. Furthermore, the outer diameter of the fiber 20 is preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. By setting the upper limit of the outer diameter of the fiber 20 within the above range, the fiber 20 becomes flexible. Therefore, by covering the distal end of the in-vivo indwelling device 1 with the fiber 20, it becomes possible to reduce the likelihood of damage to other objects due to contact of the in-vivo indwelling device 1 with the other objects.

[0025] 1 and 4, a portion of the fiber 20 extends outside the coil 10. In other words, a portion of the fiber 20 is disposed within the lumen of the coil 10, and a portion of the fiber 20 different from the portion disposed within the lumen of the coil 10 extends outside the coil 10 and is exposed.

[0026] It is preferable that one end of the fiber 20 is disposed within the lumen of the coil 10, and the other end is disposed outside the coil 10. It is also more preferable that the proximal end of the fiber 20 is disposed within the lumen of the coil 10, and the distal end is disposed outside the coil 10. By disposing one end of the fiber 20 within the lumen of the coil 10 and the other end outside the coil 10, it is easy to increase the specific surface area of ​​the fiber 20 outside the coil 10, thereby enhancing the effect of promoting thrombus formation and the effect of covering the distal end of the in-vivo indwelling device 1 with the fiber 20, making it less likely to injure other objects.

[0027] 1, 2, and 4, the fibers 20 have branch points 60 at the outside of the coil 10 where the fibers 20 branch. By having the branch points 60, the specific surface area of ​​the fibers 20 exposed from the coil 10 can be increased. As a result, thrombi can easily adhere to the surface of the fibers 20, promoting thrombus formation in the in-vivo indwelling device 1. Furthermore, the flexibility of the fibers 20 is increased, providing excellent cushioning properties. The fibers 20 exposed from the coil 10 cover the distal end of the in-vivo indwelling device 1, making it less likely to damage the luminal wall even if the distal end of the in-vivo indwelling device 1 comes into contact with the luminal wall of a biological lumen, such as the inner wall of a aneurysm, resulting in a highly safe in-vivo indwelling device 1.

[0028] The branch point 60 is a branch point where one fiber 20 branches in two or more directions. A fiber 20 in which a part of the fiber 20 splits and branches along the extending direction of the fiber 20 can also be said to be a fiber 20 having a branch point 60 where the fiber 20 branches.

[0029] The number of branch points 60 that one fiber 20 has may be one, but preferably is multiple. When one fiber 20 has multiple branch points 60, the specific surface area of ​​the fiber 20 can be increased and the flexibility of the fiber 20 can be further increased.

[0030] 1 and 4, the in-vivo indwelling device 1 preferably has a fiber bundle 30 including fibers 20, with a proximal end 30p disposed in the lumen of the coil 10 and a distal end 30d exposed from the coil 10. That is, a portion of the fiber bundle 30 including the proximal end 30p of the fiber bundle 30 is preferably disposed in the lumen of the coil 10, and a portion of the fiber bundle 30 including the distal end 30d of the fiber bundle 30 is preferably exposed to the outside from the lumen of the coil 10. Furthermore, the in-vivo indwelling device 1 preferably has a fiber bundle 30, and the fiber bundle 30 is preferably composed of a plurality of fibers 20 including fibers 20 having a branch point 60. When the in-vivo indwelling device 1 has a fiber bundle 30 including fibers 20 having a branch point 60, thrombus formation is more likely in the fiber bundle 30, enabling early thrombosis to occur. Furthermore, since the in-vivo indwelling device 1 has the fiber bundle 30, the distal end of the in-vivo indwelling device 1 can be easily covered with the fiber bundle 30, making it possible to make the in-vivo indwelling device 1 less likely to be damaged even if it comes into contact with other objects.

[0031] The fiber bundle 30 may be formed by bundling one end of each of the plurality of fibers 20, or by folding the center portion of each of the plurality of fibers 20 in half and bundling the folded portions of the plurality of fibers 20. In particular, the fiber bundle 30 is preferably formed by bundling one end of each of the plurality of fibers 20. By forming the fiber bundle 30 by bundling one end of each of the plurality of fibers 20, the plurality of fibers 20 are likely to be firmly fixed to one another, and the fibers 20 are less likely to fall off the fiber bundle 30.

[0032] The fiber bundle 30 preferably contains 5 or more fibers 20, more preferably 10 or more fibers 20, and even more preferably 15 or more fibers 20. By setting the lower limit of the number of fibers 20 in the fiber bundle 30 within the above range, the distal end 30d of the fiber bundle 30 is more likely to expand in the radial direction y. Furthermore, the fiber bundle 30 preferably contains 500 or fewer fibers 20, more preferably 400 or fewer fibers 20, and even more preferably 300 or fewer fibers 20. By setting the upper limit of the number of fibers 20 in the fiber bundle 30 within the above range, the outer diameter at the distal end 30d of the fiber bundle 30 is prevented from becoming excessively large, and the in-vivo indwelling device 1 can be made to have good insertability.

[0033] The fiber bundle 30 may contain fibers made of a material other than collagen, or all of the fibers 20 may be collagen fibers. In particular, it is preferable that all of the fibers 20 constituting the fiber bundle 30 are collagen fibers. When all of the fibers 20 constituting the fiber bundle 30 are collagen fibers, the binding between the fibers 20 and thrombi is enhanced throughout the entire fiber bundle 30, making thrombi more likely to form.

[0034] The fiber bundle 30 may have at least one fiber 20 having a branch point 60, but it is preferable that 30% or more of the fibers 20 constituting the fiber bundle 30 have a branch point 60. When 30% or more of the fibers 20 constituting the fiber bundle 30 have a branch point 60, the specific surface area of ​​the fibers 20 in the fiber bundle 30 increases, and the flexibility of the fibers 20 tends to increase. As a result, thrombi are more likely to adhere to the fiber bundle 30, enhancing the effect of promoting thrombosis, and the cushioning properties of the fiber bundle 30 are improved, making it less likely that other objects will be damaged by contact with the in-vivo indwelling device 1.

[0035] The proportion of fibers 20 having branch points 60 among all fibers 20 constituting the fiber bundle 30 is more preferably 50% or more, even more preferably 70% or more, and even more preferably 90% or more. By setting the lower limit of the proportion of fibers 20 having branch points 60 in the fiber bundle 30 within the above range, the specific surface area of ​​the fibers 20 constituting the fiber bundle 30 can be increased and the fibers 20 can be made more flexible. The upper limit of the proportion of fibers 20 having branch points 60 among all fibers 20 constituting the fiber bundle 30 is not particularly limited, but can be set to 100% or less, for example. A proportion of fibers 20 having branch points 60 in the fiber bundle 30 of 100% means that all fibers 20 constituting the fiber bundle 30 have branch points 60. In particular, it is particularly preferable that all fibers 20 constituting the fiber bundle 30 have at least one branch point 60.

[0036] As shown in Fig. 3, when the fiber bundle 30 is viewed from the distal end 30d, the fiber bundle 30 has a central region A1, which is an area surrounded by a circle having a diameter half the diameter D2 of the circumscribing circle C1 of the fiber bundle 30 and a center at the centroid P1 of the lumen of the coil 10 when viewed from the distal end 10d of the coil 10, and a peripheral region A2, which is an area obtained by excluding the central region A1 from the circumscribing circle C1 of the fiber bundle 30. It is preferable that the fiber bundle 30 has a portion in the central region A1 where the fiber density of the fiber bundle 30 is higher than the fiber density of the fiber bundle 30 in the peripheral region A2. The circumscribing circle C1 of the fiber bundle 30 refers to the smallest circumscribing circle that includes all of the fibers 20 that constitute the fiber bundle 30 when viewed from the distal end 30d. The centroid P1 of the lumen of the coil 10 refers to the centroid of the shape formed by the lumen of the coil 10 located most distally when viewed from the distal end 10d. The fiber density of the fiber bundle 30 in the central region A1 is the total area of ​​the fibers 20 per unit area in the central region A1 when the fiber bundle 30 is viewed from the distal end 30d, and is the value obtained by dividing the total area of ​​all the fibers 20 present in the central region A1 when the fiber bundle 30 is viewed from the distal end 30d by the area of ​​the central region A1. The fiber density of the fiber bundle 30 in the peripheral region A2 is the total area of ​​the fibers 20 per unit area in the peripheral region A2 when the fiber bundle 30 is viewed from the distal end 30d, and is the value obtained by dividing the total area of ​​all the fibers 20 present in the peripheral region A2 when the fiber bundle 30 is viewed from the distal end 30d by the area of ​​the peripheral region A2. The fiber bundle 30 has a portion where the fiber density of the fiber bundle 30 in the central region A1 is higher than the fiber density of the fiber bundle 30 in the peripheral region A2, and as a result, the fiber density in the central region A1 is higher, and as a result, the flexibility of the entire fiber bundle 30 can be increased. Therefore, when the distal end of the in-vivo indwelling device 1 comes into contact with the wall of the biological lumen during placement, the fiber bundle 30 can easily absorb and disperse the pressure, making it less likely to damage the wall.

[0037] Although not shown, when viewed from the distal end 30d, the fiber bundle 30 has a central portion which is a region including the centroid P1 of the lumen of the coil 10 as viewed from the distal end 10d of the coil 10, an intermediate portion which is a region located outward of the central portion, and an outer peripheral portion which is a region located outward of the central portion and the intermediate portion, and it is also preferable that the fiber bundle 30 has a configuration in which the fiber density of the fiber bundle 30 in the central and outer peripheral portions is higher than the fiber density of the fiber bundle 30 in the intermediate portion. Specifically, it is preferable that the fiber density of the fiber bundle 30 is high in the central portion, low in the intermediate portion, and high in the outer peripheral portion. By having a configuration in which the fiber density of the fiber bundle 30 in the central and outer peripheral portions is higher than the fiber density of the fiber bundle 30 in the intermediate portion, the high fiber density in the central and outer peripheral portions of the fiber bundle 30 increases flexibility, and the low fiber density in the intermediate portion increases cushioning properties of the entire fiber bundle 30. As a result, when the distal end of the in-vivo indwelling device 1 hits an object such as the wall of a biological lumen, the fiber bundle 30 can easily absorb and disperse the load, making it less likely to damage the object.

[0038] 1 and 4, the fiber bundle 30 preferably has a fixed portion 31 where the relative positions of the fiber bundle 30 and the coil 10 are fixed, and a free portion 32 where the relative positions of the fiber bundle 30 and the coil 10 are not fixed. The fixed portion 31 is a portion where the relative position of the fiber bundle 30 with the coil 10 is fixed and the relative positions of the fiber bundle 30 and the coil 10 do not change. The free portion 32 is a portion where the relative position of the fiber bundle 30 with the coil 10 is not fixed and the relative positions of the fiber bundle 30 and the coil 10 can change. As a specific example of a configuration, the fixed portion 31 of the in-vivo indwelling device 1 shown in FIG. 1 is formed by bonding the fiber bundle 30 and the coil 10 with an adhesive 15, and the relative position of the fiber bundle 30 with the coil 10 is fixed. In addition, in the fixing portion 31 of the in-vivo indwelling device 1 shown in FIG. 4, the coil 10 has a reduced diameter portion 12, which will be described later, and the fiber bundle 30 and the coil 10 are in close contact with each other at least in a part of the reduced diameter portion 12, thereby fixing the relative position of the fiber bundle 30 and the coil 10.

[0039] Because the fiber bundle 30 has the fixed portion 31, the fiber bundle 30 is fixed to the coil 10, and the length of the fibers 20 in the free portion 32 can be kept constant during delivery of the in-vivo indwelling device 1. Furthermore, because the fiber bundle 30 has the free portion 32, the fibers 20 in the free portion 32 can move relative to the coil 10. Therefore, blood can easily pass through the free portion 32 of the in-vivo indwelling device 1 after placement, making it easier for thrombus to adhere to the free portion 32, and promoting thrombus formation in the in-vivo indwelling device 1.

[0040] 1 , the fixing portion 31 preferably includes the proximal end 30p of the fiber bundle 30. By including the proximal end 30p of the fiber bundle 30 in the fixing portion 31, the proximal end portion including the proximal end 30p of the fiber bundle 30 is easily fixed to the coil 10, and the fibers 20 constituting the fiber bundle 30 are less likely to fall off from the coil 10.

[0041] The free portion 32 preferably includes the distal end 30d of the fiber bundle 30. In other words, the distal end 30d of the fiber bundle 30 is preferably located in the free portion 32 of the fiber bundle 30. By including the distal end 30d of the fiber bundle 30 in the free portion 32, the distal end portion including the distal end 30d of the fiber bundle 30 can move relative to the coil 10. As a result, blood can easily get into the spaces between the multiple fibers 20 in the free portion 32, making it easier for a thrombus to form in the free portion 32.

[0042] The number of branch points 60 located in the part of the free section 32 exposed from the coil 10 is preferably greater than the number of branch points 60 located in the fixed section 31. Furthermore, the number of branch points 60 located outside the coil 10 is preferably greater than the number of branch points 60 located in the lumen of the coil 10. By having more branch points 60 located in the part of the free section 32 exposed from the coil 10 than the number of branch points 60 located in the fixed section 31, the fibers 20 can be made flexible and the specific surface area of ​​the fibers 20 can be increased in the part of the fiber bundle 30 exposed from the coil 10. This can enhance the effect of promoting thrombosis by the in-vivo indwelling device 1 and the effect of preventing damage to other objects due to contact with the in-vivo indwelling device 1.

[0043] Furthermore, by making the number of branch points 60 located in the fixed portion 31 smaller than the number of branch points 60 located in the portion of the free portion 32 that is exposed from the coil 10, it is possible to reduce the number of branch points 60 in the portion of the fiber bundle 30 that is located within the lumen of the coil 10. Therefore, when the in-vivo indwelling device 1 passes through a curved blood vessel or the like and the coil 10 is bent, the fibers 20 that are located within the lumen of the coil 10 are less likely to be caught in gaps between the wire rods 11 that make up the coil 10 and cut, and it is possible to prevent cut fiber pieces from scattering within the body or the like.

[0044] As shown in Figures 1 and 4, the number of fibers 20 exposed to the outside of the coil 10 from the distal end 10d of the coil 10 is preferably greater than the number of fibers 20 exposed to the outside of the coil 10 from the gaps between the wire rods 11 that make up the coil 10. Note that Figures 1 and 4 illustrate a configuration in which the fibers 20 are not exposed to the outside of the coil 10 from the gaps between the wire rods 11 that make up the coil 10. By making the number of fibers 20 exposed to the outside of the coil 10 from the distal end 10d of the coil 10 greater than the number of fibers 20 exposed to the outside of the coil 10 from the gaps between the wire rods 11 that make up the coil 10, the number of fibers 20 exposed to the outside of the coil 10 from the side portions of the coil 10 can be reduced, thereby improving the slidability of the outer surface of the in-vivo indwelling device 1. As a result, the in-vivo indwelling device 1 can be smoothly inserted through a catheter when being delivered to a target site. Furthermore, when the in-vivo indwelling device 1 passes through a curved blood vessel or the like and the coil 10 is bent, the number of fibers 20 that are pinched by the wire 11 that constitutes the coil 10 can be reduced, making it less likely that the fibers 20 will be cut by the wire 11.

[0045] It is preferable that the in-vivo indwelling device 1 does not have the fibers 20 exposed to the outside of the coil 10 through gaps between the wires 11 that make up the coil 10. In other words, it is preferable that the in-vivo indwelling device 1 does not have the fibers 20 exposed to the outside of the coil 10 through gaps between the wires 11 that make up the coil 10. Since the fibers 20 are not exposed to the outside of the coil 10 through gaps between the wires 11 that make up the coil 10, the slidability of the outer surface of the side of the in-vivo indwelling device 1 can be increased, and the fibers 20 can be prevented from being pinched and cut by the wires 11 that make up the coil 10 when the coil 10 is bent.

[0046] 1 , 3 , and 4 , the diameter D2 of the circumscribing circle C1 of the fiber bundle 30 at the free portion 32 in a cross section perpendicular to the longitudinal axis direction x of the coil 10 is preferably larger than the inner diameter D3 of the distal end 10d of the coil 10. The circumscribing circle C1 of the fiber bundle 30 refers to the circumscribing circle with the largest diameter among the circles circumscribing the fiber bundle 30 at the free portion 32 in a cross section perpendicular to the longitudinal axis direction x of the coil 10, with the centroid P1 of the lumen of the coil 10 as its center. Because the diameter D2 of the circumscribing circle C1 of the fiber bundle 30 at the free portion 32 is larger than the inner diameter D3 of the distal end 10d of the coil 10, the fibers 20 constituting the fiber bundle 30 spread in the radial direction y in the free portion 32, making it easier for blood to enter between the fibers 20. As a result, thrombi are more likely to form in the fiber bundle 30.

[0047] The diameter D2 of the circumscribing circle C1 of the fiber bundle 30 at the free portion 32 in a cross section perpendicular to the longitudinal axis direction x of the coil 10 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the inner diameter D3 of the distal end 10d of the coil 10. By setting the lower limit of the ratio of the diameter D2 of the circumscribing circle C1 of the fiber bundle 30 at the free portion 32 to the inner diameter D3 of the distal end 10d of the coil 10 within the above range, the fiber bundle 30 becomes more likely to spread in the radial direction y. Furthermore, the diameter D2 of the circumscribing circle C1 of the fiber bundle 30 at the free portion 32 in a cross section perpendicular to the longitudinal axis direction x of the coil 10 is preferably 50 times or less, more preferably 40 times or less, and even more preferably 30 times or less, the inner diameter D3 of the distal end 10d of the coil 10. By setting the upper limit of the ratio between the diameter D2 of the circumscribing circle C1 of the fiber bundle 30 at the free portion 32 and the inner diameter D3 of the distal end 10d of the coil 10 within the above range, the fiber bundle 30 is less likely to spread excessively, and the insertability of the in-vivo retention device 1 during delivery can be improved.

[0048] 1 and 4, the coil 10 may further include an elongation-resistant member 40 disposed within the lumen of the coil 10. The elongation-resistant member 40 extends in the longitudinal axis direction x, and the distal and proximal ends of the elongation-resistant member 40 can be fixed directly or indirectly to the coil 10. By including the elongation-resistant member 40 in the in-vivo indwelling device 1, it is possible to suppress elongation of the coil 10 in the longitudinal axis direction x.

[0049] The extension-resistant member 40 is preferably a linear member. The extension-resistant member 40 may be a single wire or a twisted wire. The extension-resistant member 40 may also be a single layer or a multi-layer body having multiple layers. For example, the extension-resistant member 40 may have an inner layer made of twisted wire made of multiple linear members and an outer layer made of a resin composition outside the inner layer. One or more extension-resistant members 40 may be arranged in the lumen of the coil 10.

[0050] The extension-resistant member 40 is preferably made of a resin or metal material, including, for example, platinum, gold, rhodium, palladium, gold, silver, titanium, tantalum, tungsten, and alloys thereof; stainless steel; polyester resins such as polyethylene terephthalate; polyamide resins such as nylon; and polyolefin resins such as polyethylene and polypropylene. If the extension-resistant member 40 is made of a resin, flexibility can be enhanced, improving the delivery performance of the in-vivo indwelling device 1. Furthermore, an extension-resistant member 40 made of a resin is less susceptible to fracture due to metal fatigue during delivery, and can also alleviate tension caused by the end of the coil 10 being stretched linearly when the coil 10 is placed within the aneurysm due to insufficient length of the extension-resistant member 40. The extension-resistant member 40 may be made of a different material from the coil 10. Specifically, when the coil 10 is made of a platinum-tungsten alloy, the extension-resistant member 40 may be made of polypropylene resin.

[0051] The cross-sectional shape of the linear members constituting the extension resistance member 40 in the longitudinal axis direction x may be circular, elliptical, polygonal, or a combination thereof. The outer diameter of the extension resistance member 40 is preferably smaller than the inner diameter of the coil 10. The extension resistance member 40 is preferably disposed in a folded state within the lumen of the coil 10. Therefore, the outer diameter of the linear members constituting the extension resistance member 40 is preferably smaller than half the inner diameter of the coil 10, and more preferably equal to or smaller than one-third of the inner diameter of the coil 10. Furthermore, the outer diameter of the linear members constituting the extension resistance member 40 is preferably equal to or larger than one-fifteenth the inner diameter of the coil 10, and more preferably equal to or larger than one-tenth the inner diameter of the coil 10. By setting the upper limit of the outer diameter of the linear members constituting the extension resistance member 40 within the above range, the strength of the extension resistance member 40 is increased, thereby preventing breakage of the extension resistance member 40. The outer diameter of the linear member that constitutes the extension resistance member 40 can be, for example, 20 μm or more, or 25 μm or more, or 40 μm or less, or 35 μm or less.

[0052] The shape of the stretch resistance member 40 is preferably linear, wavy, or spiral. Of these, it is more preferable that the shape of the stretch resistance member 40 be wavy. By forming the stretch resistance member 40 in a wavy shape, the length of the stretch resistance member 40 in the lumen of the coil 10 can be ensured, and the phenomenon in which the end of the coil 10 is stretched linearly and becomes taut due to insufficient length of the stretch resistance member 40 can be alleviated.

[0053] 1 and 4, the in-vivo indwelling device 1 further includes an elongation-resistant member 40 disposed within the lumen of the coil 10, and the fiber bundle 30 preferably includes a bundling section 33 where the proximal ends of a plurality of fibers 20 are bundled and fixed, and the bundling section 33 is connected to the elongation-resistant member 40. The configuration in which the bundling section 33 of the fiber bundle 30 is connected to the elongation-resistant member 40 makes it easier to fix the position of the fiber bundle 30 relative to the coil 10, and reduces the likelihood of the length of the free section 32 of the fiber bundle 30 changing during delivery of the in-vivo indwelling device 1. As a result, the in-vivo indwelling device 1 can more stably exhibit its effects of promoting thrombosis and reducing damage to the walls of the biological lumen.

[0054] 1 and 4 , the bundling portion 33 of the fiber bundle 30 preferably includes a resin tube 50, and the proximal ends of the plurality of fibers 20 are disposed in the lumen of the resin tube 50. By disposing the proximal ends of the plurality of fibers 20 constituting the fiber bundle 30 in the lumen of the resin tube 50, the proximal ends of the plurality of fibers 20 can be protected by the resin tube 50. Therefore, when the coil 10 is bent by a curved blood vessel or the like, the proximal ends of the fibers 20 can be prevented from coming into contact with the coil 10, making it possible to make the fibers 20 less likely to break.

[0055] Preferred materials for the resin tube 50 include, for example, polyamide resins such as nylon, polyether polyamide resins, polyimide resins, polyester resins such as polyethylene terephthalate (PET), polyurethane resins, polyolefin resins such as polyethylene and polypropylene, fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), and ethylene tetrafluoroethylene copolymer (ETFE), thermoplastic resins such as polyvinyl chloride resins and silicone resins, and natural rubber. These materials may be used alone or in combination of two or more. Among these, the material for the resin tube 50 is preferably a fluorine-based resin, and more preferably polytetrafluoroethylene. Using a fluorine-based resin for the resin tube 50 improves the slipperiness of the inner and outer surfaces of the resin tube 50, making it easier to insert multiple fibers 20 into the lumen of the resin tube 50 and to place the fiber bundle 30 into the lumen of the coil 10 after the proximal ends of the multiple fibers 20 have been placed in the lumen of the resin tube 50.

[0056] The proximal ends of the plurality of fibers 20 can be fixed by the resin tube 50 in various ways, including, for example, forming the resin tube 50 from a material that shrinks when heated, placing the proximal ends of the plurality of fibers 20 in the lumen of the resin tube 50, and then heating the resin tube 50 to fix the proximal ends of the plurality of fibers 20; placing the proximal ends of the plurality of fibers 20 in the lumen of the resin tube 50 and then pouring an adhesive into the lumen of the resin tube 50 to fix the proximal ends of the plurality of fibers 20; or placing the proximal ends of the plurality of fibers 20 in the lumen of the resin tube 50 and then fixing the proximal ends of the plurality of fibers 20 by welding. Among these, it is preferable to fix the proximal ends of the plurality of fibers 20 by heating and shrinking the resin tube 50. Fixing the proximal ends of the plurality of fibers 20 by heat-shrinking the resin tube 50 allows the plurality of fibers 20 to be fixed easily and firmly.

[0057] 1 , the length L2 of the fixed portion 31 in the longitudinal axis direction x of the coil 10 is preferably longer than the average length of the fibers 20 exposed from the coil 10 in the free portions 32 in the longitudinal axis direction x of the coil 10. In other words, the length L2 of the fixed portion 31 in the longitudinal axis direction x of the coil 10 is preferably longer than the average length L1 of the fibers 20 exposed from the coil 10 in the free portions 32 in the longitudinal axis direction x of the coil 10. Since the length L2 of the fixed portion 31 is longer than the average length of the fibers 20 exposed from the coil 10 in the free portions 32, the proximal end portion of the fiber bundle 30 is more easily supported by the coil 10. Therefore, the distal end portions of the fibers 20 outside the coil 10 are less likely to bend independently and become more susceptible to thrombus formation in the fiber bundle 30.

[0058] The length L2 of the fixed portion 31 in the longitudinal axis direction x of the coil 10 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the average length L1 of the fibers 20 exposed from the coil 10 in the free portions 32 in the longitudinal axis direction x of the coil 10. By setting the lower limit of the ratio of the length L2 of the fixed portion 31 to the average length of the fibers 20 exposed from the coil 10 in the free portions 32 within the above range, the proximal end of the fiber bundle 30 is supported by the coil 10, making it possible to make the distal end of the fiber bundle 30 less likely to bend significantly. Furthermore, the length L2 of the fixed portion 31 in the longitudinal axis direction x of the coil 10 is preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less, the average length L1 of the fibers 20 exposed from the coil 10 in the free portions 32 in the longitudinal axis direction x of the coil 10. By setting the upper limit of the ratio of the length L2 of the fixed portion 31 to the average length of the fibers 20 exposed from the coil 10 in the free portion 32 within the above range, the length of the fibers 20 exposed from the distal end 10d of the coil 10 can be ensured, making it easier to achieve the effects of promoting thrombus formation by the fiber bundle 30 and preventing damage to other objects by covering the distal end of the in-vivo retention device 1 with the fibers 20.

[0059] 4, the coil 10 preferably has a tapered portion 12 at the distal end of the coil 10, where the inner diameter D1 of the coil 10 is reduced. By having the coil 10 have the tapered portion 12, the inner surface of the coil 10 and the fiber bundle 30 come into contact at the tapered portion 12, making it easier for the proximal end of the fiber bundle 30 to be supported by the coil 10. Therefore, distal to the tapered portion 12, the plurality of fibers 20 constituting the fiber bundle 30 are less likely to bend significantly, and the fiber bundle 30 is more likely to spread in the radial direction y.

[0060] The reduced diameter portion 12 is preferably located at the distal end of the coil 10, but the reduced diameter portion 12 may be located at the distal end 10d of the coil 10, or the distal end 12d of the reduced diameter portion 12 may be located more proximal than the distal end 10d of the coil 10. In particular, the reduced diameter portion 12 is preferably located at the distal end 10d of the coil 10. The reduced diameter portion 12 being located at the distal end 10d of the coil 10 refers to a configuration in which the position of the distal end 12d of the reduced diameter portion 12 coincides with the position of the distal end 10d of the coil 10. By having the reduced diameter portion 12 located at the distal end 10d of the coil 10, the proximal end of the fiber bundle 30 is supported by the distal end 10d of the coil 10, making the multiple fibers 20 constituting the fiber bundle 30 less likely to bend.

[0061] The minimum inner diameter of the coil 10 in the reduced diameter portion 12 is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less of the maximum inner diameter of the coil 10. By setting the upper limit of the ratio of the minimum inner diameter of the coil 10 to the maximum inner diameter of the coil 10 in the reduced diameter portion 12 within the above range, the inner surface of the coil 10 and the fiber bundle 30 in the reduced diameter portion 12 are more likely to come into contact, and the fiber bundle 30 is more likely to be supported by the reduced diameter portion 12. Furthermore, the minimum inner diameter of the coil 10 in the reduced diameter portion 12 is preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more of the maximum inner diameter of the coil 10. By setting the lower limit of the ratio of the minimum inner diameter of the coil 10 to the maximum inner diameter of the coil 10 in the reduced diameter portion 12 within the above range, it is possible to ensure the width of the lumen of the coil 10 in the reduced diameter portion 12, and it is possible to increase the number of fibers 20 constituting the fiber bundle 30 and to increase the fiber diameter.

[0062] 4 , the reduced diameter section 12 includes a proximal reduced diameter section 13 that includes a proximal end 12p of the reduced diameter section 12, and a distal reduced diameter section 14 that is located distal to the distal end of the proximal reduced diameter section 13, and the average inner diameter of the proximal reduced diameter section 13 is preferably smaller than the average inner diameter of the distal reduced diameter section 14. Since the reduced diameter section 12 includes the proximal reduced diameter section 13 and the distal reduced diameter section 14 and the average inner diameter of the proximal reduced diameter section 13 is smaller than the average inner diameter of the distal reduced diameter section 14, the inner diameter of the coil 10 at the reduced diameter section 12 increases toward the distal side in the reduced diameter section 12, causing contact between the inner surface of the coil 10 and the fiber bundle 30, which tends to spread the fiber bundle 30. As a result, blood is more likely to enter between the multiple fibers 20 that make up the fiber bundle 30, and thrombi are more likely to form in the fiber bundle 30.

[0063] The average inner diameter of the proximal tapered portion 13 is preferably 95% or less, more preferably 90% or less, and even more preferably 85% or less of the average inner diameter of the distal tapered portion 14. The average inner diameter of the proximal tapered portion 13 is preferably 35% or more, more preferably 40% or more, and even more preferably 45% or more of the average inner diameter of the distal tapered portion 14. By setting the upper and lower limits of the ratio of the average inner diameter of the proximal tapered portion 13 to the average inner diameter of the distal tapered portion 14 within the above ranges, the difference between the average inner diameter of the proximal tapered portion 13 and the average inner diameter of the distal tapered portion 14 tends to be appropriate, and the multiple fibers 20 constituting the fiber bundle 30 tend to spread out.

[0064] Although not shown, reduced diameter section 12 may further have a portion different from proximal reduced diameter section 13 and distal reduced diameter section 14. Specifically, for example, a portion having an inner diameter, etc. different from those of proximal reduced diameter section 13 and distal reduced diameter section 14 may be located proximal to proximal reduced diameter section 13, distal to proximal reduced diameter section 13 and proximal to distal reduced diameter section 14, or distal to distal reduced diameter section 14.

[0065] 4, the length L1 of the fibers 20 exposed from the coil 10 in the free portion 32 in the longitudinal axis direction x of the coil 10 is preferably longer than the length L3 of the tapered portion 12 in the longitudinal axis direction x of the coil 10. When the length L1 of the fibers 20 exposed from the coil 10 in the free portion 32 is longer than the length L3 of the tapered portion 12, the fiber bundle 30 tends to spread widely distal to the distal end 10d of the coil 10. This makes it easier for blood to enter between the multiple fibers 20 constituting the fiber bundle 30, thereby promoting thrombosis.

[0066] The length L1 of the fibers 20 exposed from the coil 10 in the free portion 32 in the longitudinal axis direction x of the coil 10 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the length L3 of the tapered portion 12 in the longitudinal axis direction x of the coil 10. By setting the lower limit of the ratio of the length L1 of the fibers 20 exposed from the coil 10 in the free portion 32 to the length L3 of the tapered portion 12 within the above range, the length L1 of the fibers 20 exposed from the coil 10 is likely to be sufficient, and the fiber bundle 30 can more easily exhibit the effect of promoting thrombosis, the effect of covering the distal end of the coil 10 with the fiber bundle 30 to make it less likely to damage the wall of a lumen in a living body, and the effect of inhibiting migration of the in-vivo indwelling device 1 by entanglement of multiple fibers 20. Furthermore, the length L1 of the fibers 20 exposed from the free portion 32 in the longitudinal axis direction x of the coil 10 is preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less, the length L3 of the tapered portion 12 in the longitudinal axis direction x of the coil 10. By setting the upper limit of the ratio between the length L1 of the fibers 20 exposed from the coil 10 in the free portion 32 and the length L3 of the tapered portion 12 within the above range, the proximal end of the fiber bundle 30 can be more easily supported by the tapered portion 12, and the fibers 20 exposed from the coil 10 are less likely to bend significantly.

[0067] This application claims the benefit of priority based on Japanese Patent Application No. 2023-214556, filed on December 20, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-214556, filed on December 20, 2023, are incorporated herein by reference.

[0068] DESCRIPTION OF SYMBOLS 1: In-vivo indwelling device 10: Coil 10d: Distal end of coil 11: Wire 12: Tapered portion 12d: Distal end of tapered portion 12p: Proximal end of tapered portion 13: Proximal tapered portion 14: Distal tapered portion 15: Adhesive 20: Fiber 30: Fiber bundle 30d: Distal end of fiber bundle 30p: Proximal end of fiber bundle 31: Fixed portion 32: Free portion 33: Bundled portion 40: Elongation-resistant member 50: Resin tube 60: Branch point C1: Circumscribed circle of fiber bundle at free portion P1: Centroid of lumen of coil as viewed from distal end of coil A1: Central region A2: Peripheral region L1: Length of fiber exposed from coil L2: Length of fixed portion L3: Length of tapered portion D1: Inner diameter of coil D2: Diameter of circumscribed circle of fiber bundle at free portion D3: inner diameter of the distal end of the coil x: longitudinal direction y: radial direction z: circumferential direction

Claims

1. An in-vivo indwelling device comprising: a coil in which wire is wound and has a longitudinal axis; and a fiber disposed in the inner cavity of said coil, a portion of said fiber extending outside said coil, and a branch point where said fiber branches outside said coil.

2. The in vivo indwelling device according to claim 1, further comprising a fiber bundle containing said fibers, said proximal end being disposed within the lumen of said coil and said distal end being exposed from said coil.

3. The in vivo indwelling device according to claim 2, wherein 30% or more of all the fibers constituting said fiber bundle have said branch points.

4. An in-vivo retention device as described in claim 2, wherein said fiber bundle has a central region which is an area surrounded by a circle whose diameter is half the diameter of the circumscribing circle of said fiber bundle when viewed from the distal end of said coil and whose center is the centroid of the lumen of said coil when viewed from the distal end of said coil, and a peripheral region which is the area obtained by excluding said central region from the circumscribing circle of said fiber bundle, and wherein said fiber bundle has a portion in which the fiber density of said fiber bundle in said central region is higher than the fiber density of said fiber bundle in said peripheral region.

5. An in-vivo retention device as described in claim 2, wherein the fiber bundle has a fixed portion in which the relative position of the fiber bundle and the coil is fixed, and a free portion in which the relative position of the fiber bundle and the coil is not fixed, and the number of the branch points located in the part of the free portion exposed from the coil is greater than the number of the branch points located in the fixed portion.

6. The in-vivo indwelling device according to claim 5, wherein the diameter of a circumscribed circle of said fiber bundle at said free portion in a cross section perpendicular to the longitudinal axis direction of said coil is larger than the inside diameter of said coil at its distal end.

7. The in-vivo retention device according to claim 2, further comprising an elongation resistant member disposed within the inner cavity of the coil, the fiber bundle having a bundling section at which the proximal ends of a plurality of the fibers are bundled and fixed, and the bundling section and the elongation resistant member are connected.

8. The in-vivo indwelling device according to claim 7, wherein the bundling portion has a resin tube, and the proximal ends of a plurality of the fibers are disposed in the lumen of the resin tube.

9. The in-vivo retention device according to claim 5, wherein the length of the fixed portion in the longitudinal direction of the coil is longer than the average length of the fibers exposed from the coil in the free portion in the longitudinal direction of the coil.

10. The in-vivo indwelling device according to claim 1, wherein said coil has a tapered portion at a distal end thereof where the inside diameter of said coil is reduced.

11. The in-vivo retention device according to claim 10, wherein the reduced diameter portion includes a proximal reduced diameter portion including a proximal end of the reduced diameter portion, and a distal reduced diameter portion located distal to the distal end of the proximal reduced diameter portion, and the average inner diameter of the proximal reduced diameter portion is smaller than the average inner diameter of the distal reduced diameter portion.

12. An in-vivo retention device as described in claim 10 or 11, wherein the fiber bundle has a fixed portion in which the relative position of the fiber bundle and the coil is fixed, and a free portion in which the relative position of the fiber bundle and the coil is not fixed, and the length of the fiber exposed from the coil in the free portion in the longitudinal axis direction of the coil is longer than the length of the reduced diameter portion in the longitudinal axis direction of the coil.

13. The in-vivo indwelling device according to claim 1, wherein said fibers contain collagen.

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