Intra-biovenous implantation devices and intra-biovenous implantation device delivery systems

Abstract

An in-vivo indwelling device (10) comprises: a coil (11) having a distal end and proximal end in the longitudinal direction (x), and having a head part (13) provided to the distal end thereof and a lumen (11a) extending in the longitudinal axis direction; and a stretch resistance member (20) disposed in the lumen (11a), wherein the coil (11) has a main section (30) excluding 5% at both ends of the length in the longitudinal axis direction (x), and when the main section (30) is divided into three equal sections of the distal section (31), the central section (32), and the proximal section (33), the average value of the outer diameter of the coil (11) in the central section (32) is less than or equal to the average value of the outer diameter of the coil (11) in the proximal section (33), the average value of the outer diameter of the coil (11) in the distal section (31) is less than or equal to the average value of the outer diameter of the coil (11) in the central section (32), and the average value of the outer diameter of the coil (11) in the distal section (31) is less than the average value of the outer diameter of the coil (11) in the proximal section (33).

Description

Technical Field

[0001] The present invention relates to an intravascular implant for forming an embolism in a blood vessel of a diseased blood vessel portion and a delivery system thereof.

Background Art

[0002] As one of the treatment methods for vascular lesions such as aneurysms, arteriovenous malformations, arteriovenous fistulas, pulmonary vascular malformations, renal vascular malformations, renal arteries, abdominal aneurysms, etc. in the head and neck, endovascular treatment is mentioned. An embolization procedure is used to prevent, for example, rupture of an aneurysm by placing an intravascular implant having a coil for embolization at the target site and promoting thrombosis. In the embolization procedure, a technique of packing coils into the aneurysm is performed, and it has phases of Framing, Filling, and Finishing. In the embolization procedure, implants with different flexibilities are generally selected for each phase. For example, in the Framing phase, it is necessary to create a shape that forms the framework of the implant by making the coil crawl along the inner surface of the aneurysm. On the other hand, in the phases after Filling, since the coil is filled into the framework formed in Framing, a coil having higher flexibility than that in Framing is selected. Several to several tens of coils are used in one embolization procedure.

[0003] As an example of an intravascular implant, Patent Document 1 discloses a primary winding coil having a longitudinal axis, which includes a flexible metal wire wound in a helical shape around the longitudinal axis of the coil, and the coil is elongated along the longitudinal axis and has a non-circular cross-sectional shape. The axis of the non-circular cross-sectional shape precesses along the longitudinal axis to form a repeated twisted coil pattern. The coil has substantially uniform flexibility throughout the longitudinal axis direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] While many indwelling devices have uniform flexibility from the distal end to the proximal end of the coil, increasing the options for indwelling devices is beneficial for performing procedures more efficiently. Therefore, the present invention aims to provide an in-vivo indwelling device and its delivery system that contributes to the efficiency of the procedure. [Means for solving the problem]

[0006] One embodiment of the in-vivo implantation device of the present invention, which has achieved the above objective, is a coil having a distal end and a proximal end in the longitudinal axis direction, comprising a head portion provided at the distal end, a coil having a lumen extending in the longitudinal axis direction, and a stretch resistance member disposed in the lumen of the coil, wherein the coil has a main section excluding 5% of its length in the longitudinal axis direction at both ends, and when the main section is divided into three equal parts, a distal section, a central section, and a proximal section, the average value of the outer diameter of the coil in the central section is less than or equal to the average value of the outer diameter of the coil in the proximal section, the average value of the outer diameter of the coil in the distal section is less than or equal to the average value of the outer diameter of the coil in the central section, and the average value of the outer diameter of the coil in the distal section is smaller than the average value of the outer diameter of the coil in the proximal section. As a result, even in the later stages of the process of delivering a single coil into the aneurysm, the coil remains flexible, making insertion and filling easier and contributing to increased efficiency in the procedure.

[0007] In the above-described in-vivo implantation device, it is preferable that the reaction force applied to the indenter in the proximal section is smaller than the reaction force applied to the indenter in the distal section when a disc-shaped indenter is pressed in from a direction perpendicular to the longitudinal axis of the coil at a predetermined speed to an extent of 5% of the outer diameter of the coil.

[0008] In the above-described in-vivo implantation device, it is preferable that the reaction force applied to the indenter in the proximal section is smaller than the reaction force applied to the indenter in the central section when a disc-shaped indenter is pressed in from a direction perpendicular to the longitudinal axis of the coil at a predetermined speed to an extent of 5% of the outer diameter of the coil.

[0009] In the above-described in-vivo implantation device, it is preferable that the coil has a first coil portion having a constant outer diameter, and a second coil portion located proximal to the first coil portion, having a constant outer diameter, and having a larger outer diameter overall than the first coil portion.

[0010] In the above-mentioned in-vivo implantation device, it is preferable that the second coil portion is longer than the first coil portion in the longitudinal axis direction of the coil.

[0011] In the above-described in-vivo implantation device, it is preferable that the coil has a first transition section between the first coil section and the second coil section, the outer diameter of which decreases toward the distal end.

[0012] In the above-described in-vivo implantation device, when the in-vivo implantation device is left stationary without applying external force, the first coil section and the second coil section each have a shape that combines a first shape in which the coil forms an annular loop and a second shape in which the coil is curved without forming an annular loop, and the portion between the first coil section and the second coil section preferably has a shape that combines only the first shape in which the coil forms an annular loop.

[0013] In the above-described in-vivo implantation device, it is preferable that the coil has a third coil portion located proximal to the second coil portion, having a constant outer diameter, and having a larger outer diameter overall than the second coil portion.

[0014] In the above-described in-vivo implantation device, it is preferable that the coil has a second transition section located between the second coil section and the third coil section, with its outer diameter decreasing toward the distal end.

[0015] In the above-described in-vivo implantation device, it is preferable that, when the in-vivo implantation device is left stationary without applying external force, the first coil portion and the third coil portion each have a shape that combines a first shape in which the coil forms an annular loop and a second shape in which the coil is curved without forming an annular loop, and the second coil portion has a shape that combines only the first shape in which the coil forms an annular loop.

[0016] In the above-described in-vivo implantation device, it is preferable that the coil has a fourth coil portion located between the first coil portion and the second coil portion, and whose outer diameter changes periodically.

[0017] In the above-mentioned in-vivo implantation device, it is preferable that the fourth coil portion is longer than the first coil portion in the longitudinal axis direction of the coil.

[0018] In the above-described in-vivo implantation device, it is preferable that the main section of the coil has three or more curved sections when the in-vivo implantation device is left stationary without any external force being applied.

[0019] The present invention also provides an in-vivo implantation device delivery system. One embodiment of the in-vivo implantation device delivery system of the present invention comprises the above-mentioned in-vivo implantation device and a pusher detachably connected to the proximal end of the coil, wherein the outer diameter of the distal end of the pusher is larger than the outer diameter of the proximal end of the coil. Because the coil is less likely to buckle when pushed distally by the pusher, insertion and filling of the coil into the aneurysm becomes smoother, contributing to the efficiency of the procedure. [Effects of the Invention]

[0020] The above-described in-vivo implantation device and its delivery system facilitate the smooth insertion and filling of coils into aneurysms, thereby contributing to increased efficiency in the procedure. [Brief explanation of the drawing]

[0021] [Figure 1] This is a side view (partially a cross-sectional view) of an in-vivo implantable device according to one embodiment of the present invention. [Figure 2]A side view of an intravascular implant delivery system according to an embodiment of the present invention. [Figure 3] A schematic diagram showing a method for measuring the reaction force of the coil of the intravascular implant shown in FIG. 1. [Figure 4] A schematic diagram of the pressure element shown in FIG. 3. [Figure 5] An enlarged side view of the coil shown in FIG. 1. [Figure 6] A side view showing a modified example of the coil shown in FIG. 5. [Figure 7] A side view showing a modified example of the coil shown in FIG. 6. [Figure 8] A schematic diagram showing an example of the shape of the first coil portion of the coil shown in FIG. 1 in a state of being stationary without applying an external force. [Figure 9] A schematic diagram showing an example of the shape of the portion between the first coil portion and the second coil portion of the coil shown in FIG. 1 in a state of being stationary without applying an external force. [Figure 10] A schematic diagram showing an example of the shape of a part of the main section of the coil of the intravascular implant according to another embodiment of the present invention in a state of being stationary without applying an external force. [Figure 11] A side view of a coil according to still another embodiment of the present invention. [Figure 12] A side view showing a modified example of the coil shown in FIG. 11. [Figure 13] A side view showing another modified example of the coil shown in FIG. 11.

Mode for Carrying Out the Invention

[0022] The present invention will be described in more detail below based on the embodiments described below. However, the present invention is not limited by the embodiments described below, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case please refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority has been given to helping to understand the features of the present invention.

[0023] One embodiment of the in-vivo implantation device of the present invention is a coil having a distal end and a proximal end in the longitudinal direction, comprising a head portion provided at the distal end, a coil having a lumen extending in the longitudinal direction, and a stretch resistance member disposed in the lumen of the coil, wherein the coil has a main section excluding 5% of its length in the longitudinal direction from both ends, and when the main section is divided into three equal parts, a distal section, a central section, and a proximal section, the average value of the outer diameter of the coil in the central section is less than or equal to the average value of the outer diameter of the coil in the proximal section, the average value of the outer diameter of the coil in the distal section is less than or equal to the average value of the outer diameter of the coil in the central section, and the average value of the outer diameter of the coil in the distal section is smaller than the average value of the outer diameter of the coil in the proximal section. As a result, even in the later stages of the process of delivering a single coil into the aneurysm, the coil remains flexible, making insertion and filling easier and contributing to increased efficiency in the procedure.

[0024] Examples of the use of in vivo implantable devices include embolization to promote thrombosis at target sites such as head and neck aneurysms, arteriovenous malformations, arteriovenous fistulas, pulmonary vascular malformations, renal vascular malformations, renal artery aneurysms, and abdominal aneurysms. Embolization has three phases: framing, filling, and finishing. In vivo implantable devices can be used in one of these phases, or in two or three phases. Hereafter, in vivo implantable devices may be simply referred to as implantable devices.

[0025] The configuration of the in-vivo implantation device and the in-vivo implantation device delivery system will be described with reference to Figures 1 to 7. Figure 1 is a side view (partially a cross-sectional view) of an in-vivo implantation device according to one embodiment of the present invention. Figure 2 is a side view of an in-vivo implantation device delivery system according to one embodiment of the present invention. Figure 3 is a schematic diagram showing a method for measuring the reaction force of the coil of the in-vivo implantation device shown in Figure 1. Figure 4 is a schematic diagram of the indenter shown in Figure 3. Figure 5 is an enlarged side view of the coil shown in Figure 1. Figure 6 is a side view showing a modified example of the coil shown in Figure 5. Figure 7 is a side view showing a modified example of the coil shown in Figure 6. The in-vivo implantation device 10 comprises a coil 11 and a stretch resistance member 20. The in-vivo implantation device delivery system 1 comprises the in-vivo implantation device 10 and a pusher 3.

[0026] As can be seen from Figure 1, the coil 11 has a distal end and a proximal end in the longitudinal axis x. The proximal side of the coil 11 refers to the direction toward the user or operator's hand with respect to the longitudinal axis x of the coil 11, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target.

[0027] The coil 11 is formed by winding one or more wires 12 in a helical shape. The wires 12 are preferably single wires, but may also be stranded wires. It is preferable that the wires 12 are not coiled. A coil formed by winding wires 12 in a helical shape is sometimes called a primary coil. A primary coil that has been further shaped into a helical or three-dimensional shape is sometimes called a secondary coil. In Figure 1, the coil 11 is shown in a straight line, and if the coil 11 has a secondary shape, the figure shows the state of a primary coil that has been straightened out of the secondary coil.

[0028] The coil 11 has a lumen 11a that extends in the longitudinal axis direction x. A stretch resistance member 20, which will be described later, is placed in the lumen 11a.

[0029] The coil 11 may be a single-layer coil or a multi-layer coil having multiple layers. A portion of the coil 11 along its longitudinal axis x may be single-layered, while the remaining portion is multi-layered. Figure 1 shows an example where the coil 11 is single-layered along its entire longitudinal axis x.

[0030] The density of the coil 11, i.e., the winding spacing, is not particularly limited and can be tightly wound, pitched, or a combination of these. In the coil 11, adjacent wires 12 may be in contact with each other in a portion of the longitudinal axis x, or adjacent wires 12 may be in contact with each other along the entire longitudinal axis x. The state in which adjacent wires 12 of the coil 11 are in contact in the longitudinal axis x is called tightly wound, and the state in which they are not in contact is called pitched wound. The state in which they are not in contact means that there is a gap between adjacent wires 12 of the coil 11 in the longitudinal axis x.

[0031] The shape of the cross-section of the coil 11 perpendicular to the longitudinal axis x may be circular, oval, polygonal, or a combination thereof. The oval shape includes elliptical, egg-shaped, and rounded rectangular shapes. The same applies in the following description.

[0032] The maximum and minimum outer diameters of the coil 11 are not particularly limited and can be appropriately selected according to the phase of the procedure. For example, they may be 150 μm or more, 180 μm or more, or 200 μm or more, and may also be 400 μm or less, 380 μm or less, or 350 μm or less.

[0033] The wire 12 is preferably biocompatible and flexible. Examples of materials constituting the wire 12 include platinum, gold, titanium, tungsten and their alloys, stainless steel, and other metallic materials or combinations thereof. Among these, it is more preferable that the wire 12 is composed of a platinum-tungsten alloy.

[0034] The cross-sectional shape of the wire 12 perpendicular to the longitudinal axis may be circular, oval, polygonal, or a combination thereof.

[0035] The outer diameter of the wire 12 is not particularly limited, but may be, for example, 25 μm or more, 30 μm or more, or 35 μm or more, and may be 75 μm or less, or 70 μm or less.

[0036] The wire 12 has a distal end and a proximal end in the longitudinal direction. The wire 12 may be composed of a single linear member from the distal end to the proximal end, or it may be composed of multiple linear members connected to each other in the longitudinal direction.

[0037] The coil 11 has a head portion 13 at its distal end. The head portion 13 covers a part of the wire 12 to prevent the distal end of the wire 12 from directly contacting the inner wall of the blood vessel. The head portion 13 may or may not be in contact with the stretch resistance member 20, which will be described later.

[0038] The shape of the head portion 13 is not particularly limited, but may be, for example, hemispherical, semi-elongated, cylindrical, or polygonal prism.

[0039] The head portion 13 may be joined to at least one of the outer or inner surfaces of the coil 11. In addition, to prevent the head portion 13 from falling off, a part of the head portion 13 may be placed in the lumen 11a at the distal end of the coil 11. The proximal end of the head portion 13 may be located distal to the distal end of the wire 12, and vice versa.

[0040] The head portion 13 may be made of a metal material or a resin. Examples of resins that make up the head portion 13 include thermoplastic resins and ultraviolet curing resins. In particular, using an ultraviolet curing resin eliminates the need for a heat source when joining it to the wire 12. Specifically, epoxy acrylate resins, urethane acrylate resins, and polyester acrylate resins can be used as the resins that make up the head portion 13. The metals that make up the head portion 13 can be those listed in the description of the wire 12. The materials of the wire 12 and the head portion 13 may be the same or different.

[0041] The stretch resistance member 20 suppresses the stretching of the coil 11 in the longitudinal axis direction x during operation. The stretch resistance member 20 is positioned in the lumen 11a of the coil 11. The stretch resistance member 20 may be a long member made of a single wire or a stranded wire. The stretch resistance member 20 has a first end and a second end in the longitudinal axis direction. The stretch resistance member 20 may be a single layer or a multilayer having multiple layers. The stretch resistance member 20 may have an inner layer made of a stranded wire made of multiple wires and an outer layer made of a resin composition provided outside the inner layer. The stretch resistance member 20 may be positioned as one or multiple members in the lumen 11a.

[0042] The stretch resistance member 20 may be made of resin or metal. Examples of resins that make up the stretch resistance member 20 include polyester resins such as polyethylene terephthalate, polyamide resins such as nylon, and polyolefin resins such as polyethylene and polypropylene. Being made of resin increases flexibility and improves the delivery performance of the retaining device 10. Also, if the stretch resistance member 20 is made of resin, fracture due to metal fatigue during delivery can be eliminated. By making the length of the stretch resistance member 20 longer than the length of the coil 11, or by using a material that is easily stretched for the stretch resistance member 20, it is possible to alleviate the tension caused by the end of the coil 11 stretching in a straight line when the length of the stretch resistance member 20 is insufficient when the coil 11 is placed in the knot. Examples of metals that make up the stretch resistance member 20 include platinum, gold, rhodium, palladium, rhenium, silver, nickel, titanium, tantalum, tungsten and their alloys, and stainless steel.

[0043] The stretch resistance member 20 may be made of a different material than the wire 12 that constitutes the coil 11. For example, the coil 11 may be made of a platinum-tungsten alloy, and the stretch resistance member 20 may be made of polypropylene resin.

[0044] The stretch resistance member 20 may have a cross-sectional shape perpendicular to its longitudinal axis that is circular, oval, polygonal, or a combination thereof.

[0045] Due to the arrangement of the stretch resistance member 20 in the lumen 11a of the coil 11, the outer diameter of the stretch resistance member 20 is required to be smaller than the inner diameter of the coil 11. For this reason, the outer diameter of the stretch resistance member 20 is preferably less than half of the inner diameter of the coil 11, and more preferably one-third or less. In order to prevent the stretch resistance member 20 from breaking, the outer diameter of the stretch resistance member 20 is preferably one-fifteenth or more of the inner diameter of the coil 11, and more preferably one-tenth or more.

[0046] The stretch resistance member 20 can be linear, wave-shaped, or helical. In particular, if the stretch resistance member 20 is wave-shaped, it can be smoothly placed to the end of the coil 11, and the length of the stretch resistance member 20 can be ensured within the lumen 11a of the coil 11. As a result, the phenomenon in which the length of the stretch resistance member 20 is insufficient during the procedure and the end of the coil 11 in the longitudinal axis direction x stretches linearly and becomes taut can be mitigated.

[0047] The stretch resistance member 20 may be connected to the distal end of the coil 11, or for example, to the distal end of the wire 12 that constitutes the coil 11.

[0048] The first end of the stretch resistance member 20 in the longitudinal direction may be connected to the distal end of the coil 11. In that case, the second end of the stretch resistance member 20 in the longitudinal direction may be connected to the detachment portion 2 of the in-vivo implantation device delivery system 1, which will be described later. The second end of the stretch resistance member 20 in the longitudinal direction may be connected to the proximal end of the coil 11, for example, the proximal end of the wire 12 that constitutes the coil 11. The second end of the stretch resistance member 20 in the longitudinal direction may be connected to the connection portion between the coil 11 and the pusher 3.

[0049] As shown in Figure 1, the stretch resistance member 20 is positioned in the lumen 11a of the coil 11 in a folded state midway along its longitudinal axis, and the folded portion 21 of the stretch resistance member 20 may be connected to the distal end of the wire 12. In that case, the first and second ends of the stretch resistance member 20 in the longitudinal axis direction can be connected to the proximal end of the coil 11, the detachment portion 2, or the connection portion between the coil 11 and the pusher 3. In Figure 1, the folded portion 21 of the stretch resistance member 20 is hooked onto the distal end of the coil 11, and the first and second ends of the stretch resistance member 20 are tied to the distal end of the detachment portion 2.

[0050] Methods for connecting the stretch resistance member 20 to other members include physical fixing methods such as welding, crimping, adhesive bonding, engagement, linking, binding, ligation, or combinations thereof. Here, "connection" includes both a direct connection between the two elements and a direct connection between the two elements via one or more other elements.

[0051] Referring to Figure 2, an example of the configuration of the in-vivo implantation device delivery system 1 will be described. Preferably, as shown in Figure 2, the in-vivo implantation device delivery system 1 includes an implantation device 10, a detachment part 2 connected to the proximal end of the implantation device 10, and a pusher 3 connected to the coil 11 of the implantation device 10 via the detachment part 2.

[0052] Methods for separating the retaining device 10 and the pusher 3 include chemically dissolving, electrolytically dissolving, or thermally dissolving the separation portion 2, pushing out the retaining device 10 with water pressure, releasing the mechanical engagement, or electrolyzing the separation portion 2. Furthermore, a method of dissolving the resin wire, which constitutes the separation portion 2, by applying a high-frequency current is preferably used. In this case, a high-frequency power supply is connected to the pusher 3. By generating Joule heat at the distal end of the pusher 3 using the high-frequency power supply, the separation portion 2 connecting the retaining device 10 and the pusher 3 can be melted.

[0053] The detachment part 2 is not particularly limited as long as it is configured to allow the retaining device 10 and the pusher 3 to be separated, but for example, it can be a linear or rod-shaped member. The detachment part 2 can be made of resin or metal. When the detachment part 2 is melted by Joule heating as described above, it is preferable to use a hydrophilic resin of a synthetic polymer material such as polyvinyl alcohol (PVA), PVA crosslinked polymer, PVA water-absorbing gel freeze-thaw elastomer, or ethylene vinyl alcohol copolymer as the resin constituting the detachment part 2.

[0054] The pusher 3 is a rod-shaped or wire-shaped member used to hold the indwelling device 10 and push it distally. The pusher 3 can consist of one or more members. The pusher 3 may consist of a wire member, a coil member, or a combination thereof. The pusher 3 may be made of a conductive material such as stainless steel.

[0055] To determine the position of the implantation device 10 within the body, the pusher 3 may be provided with an X-ray contrast marker. Preferably, the X-ray contrast marker is provided on at least one of the distal end and the proximal end of the pusher 3. The contrast marker may be ring-shaped or coil-shaped. A protective layer may be provided on the outer surface of the pusher 3. Preferably, the protective layer is made of a fluororesin such as polytetrafluoroethylene (PTFE). The protective layer improves the sliding properties between the pusher 3 and other components such as the catheter.

[0056] As shown in Figure 2, the in-vivo implantation device delivery system 1 includes a pusher 3 that is detachably connected to the proximal end of the coil 11, and it is preferable that the outer diameter of the distal end of the pusher 3 is larger than the outer diameter of the proximal end of the coil 11. This makes it less likely for the coil 11 to buckle even when the coil 11 is pushed distally by the pusher 3.

[0057] As shown in Figure 1, the coil 11 has a main section 30 that excludes 5% from each end of its longitudinal axis length x. When the main section 30 is divided into three equal parts: a distal section 31, a central section 32, and a proximal section 33, the average outer diameter of the coil 11 in the central section 32 is less than or equal to the average outer diameter of the coil 11 in the proximal section 33, the average outer diameter of the coil 11 in the distal section 31 is less than or equal to the average outer diameter of the coil 11 in the central section 32, and the average outer diameter of the coil 11 in the distal section 31 is smaller than the average outer diameter of the coil 11 in the proximal section 33. In the above-described implantation device 10, since the average outer diameter of the coil 11 in the distal section 31, central section 32, and proximal section 33 is set as described above, a single coil 11 can be made flexible from the distal side to the proximal side. As a result, even in the latter half of the process of feeding a single coil 11 into the tumor, the coil 11 remains flexible, making it easier to insert and fill the coil 11 smoothly, thus contributing to the efficiency of the procedure.

[0058] The intervals are hypothetically defined to calculate the average value of the outer diameter within a certain range in the longitudinal axis x of the coil 11. Dividing the main interval 30 into three equal parts—a distal interval 31, a central interval 32, and a proximal interval 33—means that the main interval 30 is hypothetically divided into three equal parts—a distal interval 31, a central interval 32, and a proximal interval 33. Therefore, the boundary between the end section in the longitudinal axis x direction from the main interval 30 and the main interval 30, the boundary between the distal interval 31 and the central interval 32, or the boundary between the central interval 32 and the proximal interval 33 may be indicated on the coil 11, but are not required. The above intervals are defined with the coil 11 unfolded in a straight line, and if the coil 11 has a secondary shape, they are defined with the primary coil obtained by straightening the secondary coil.

[0059] The outer diameters of the distal section 31, central section 32, and proximal section 33 of coil 11 are measured by the following method. First, M measurement points are set in each of the distal section 31, central section 32, and proximal section 33. M is an integer between 10 and 300. Measurement points are placed at the distal and proximal ends of each section. Next, with coil 11 in the primary coil state as shown in Figure 1, the outer diameter of coil 11 is measured using a caliper, micrometer, projection dimension measuring instrument, imaging dimension measuring instrument, etc. The primary coil state as shown in Figure 1 refers to the primary coil of coil 11 itself or the secondary coil in a straight line. A holder or a tube member through which coil 11 can be inserted can be used to maintain the straight line state of coil 11. The outer diameter of the straight coil 11 is measured directly, or the outer diameter of coil 11 is measured indirectly using an image projected or photographed of the straight coil 11. The same measurement method is used for each section.

[0060] It is preferable that the average outer diameter of the coil 11 in the distal section 31 is smaller than the average outer diameter of the coil 11 in the central section 32. This allows the flexibility of the coil 11 to be changed midway through the process of feeding one coil 11 into the nodule, making it easier to insert and fill the coil 11 smoothly.

[0061] The average outer diameter of the coil 11 in the distal section 31 is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less of the average outer diameter of the coil 11 in the central section 32. This allows for a difference in the flexibility of the coil 11 between the distal section 31 and the central section 32 that can be felt by the operator.

[0062] It is preferable that the average outer diameter of the coil 11 in the central section 32 is smaller than the average outer diameter of the coil 11 in the proximal section 33. This allows the coil 11 to remain flexible even in the later stages of the process of feeding a single coil 11 into the nodule, making it easier to insert and fill the coil 11 smoothly.

[0063] The average outer diameter of the coil 11 in the distal section 31 is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more, of the average outer diameter of the coil 11 in the central section 32. This ensures the strength of the coil 11 in the distal section 31.

[0064] The average outer diameter of the coil 11 in the central section 32 is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less of the average outer diameter of the coil 11 in the proximal section 33. This allows for a difference in the flexibility of the coil 11 between the central section 32 and the proximal section 33 that can be felt by the operator.

[0065] The average outer diameter of the coil 11 in the central section 32 is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more of the average outer diameter of the coil 11 in the proximal section 33. This ensures the strength of the coil 11 in the central section 32.

[0066] As shown in Figure 3, when a disc-shaped indenter 50 is pressed into the coil 11 from a direction perpendicular to the longitudinal axis x at a predetermined speed by an amount equal to 5% of the outer diameter of the coil 11, it is preferable that the reaction force applied to the indenter 50 in the proximal section 33 is smaller than the reaction force applied to the indenter 50 in the distal section 31. This ensures that the flexibility of the coil 11 in the proximal section 33 is greater than that in the distal section 31. The outer diameter of the coil 11 used to specify the amount of indentation of the indenter 50 is the outer diameter of the coil 11 at the point where the reaction force is measured. The same applies in the following explanation.

[0067] When a disc-shaped indenter 50 is pressed against the coil 11 from a direction perpendicular to the longitudinal axis x at a predetermined speed by an amount equal to 5% of the outer diameter of the coil 11, the reaction force applied to the indenter 50 in the proximal section 33 is preferably 0.9 times or less the reaction force applied to the indenter 50 in the distal section 31, and may be 0.8 times or less, or 0.7 times or less. This ensures greater flexibility of the coil 11 in the proximal section 33 compared to the distal section 31.

[0068] When a disc-shaped indenter 50 is pressed against the coil 11 from a direction perpendicular to the longitudinal axis x at a predetermined speed by an amount equal to 5% of the outer diameter of the coil 11, the reaction force applied to the indenter 50 in the proximal section 33 is preferably 0.3 times or more the reaction force applied to the indenter 50 in the distal section 31, and may be 0.4 times or more, or 0.5 times or more. This makes it possible to ensure both flexibility and strength of the coil 11 in the proximal section 33.

[0069] When a disc-shaped indenter 50 is pressed against the coil 11 from a direction perpendicular to the longitudinal axis x at a predetermined speed by an amount equal to 5% of the outer diameter of the coil 11, it is preferable that the reaction force applied to the indenter 50 in the proximal section 33 is smaller than the reaction force applied to the indenter 50 in the central section 32. This ensures that the flexibility of the coil 11 in the central section 32 is greater than that in the distal section 31.

[0070] When a disc-shaped indenter 50 is pressed against the coil 11 from a direction perpendicular to the longitudinal axis x at a predetermined speed by an amount equal to 5% of the outer diameter of the coil 11, the reaction force applied to the indenter 50 in the proximal section 33 is preferably 0.9 times or less the reaction force applied to the indenter 50 in the central section 32, and may be 0.8 times or less, or 0.7 times or less. This ensures greater flexibility of the coil 11 in the central section 32 compared to the distal section 31.

[0071] When a disc-shaped indenter 50 is pressed against the coil 11 from a direction perpendicular to the longitudinal axis x at a predetermined speed by an amount equal to 5% of the outer diameter of the coil 11, the reaction force applied to the indenter 50 in the proximal section 33 is preferably 0.3 times or more the reaction force applied to the indenter 50 in the central section 32, and may be 0.4 times or more, or 0.5 times or more. This makes it possible to ensure both flexibility and strength of the coil 11 in the proximal section 33.

[0072] The reaction force of coil 11 is measured using the following procedure. Note that in Figure 3, the measuring instrument, including the sample stage and universal testing machine, is omitted from the description.

[0073] First, N measurement points are set in the distal section 31, the central section 32, and the proximal section 33, respectively. N is an integer between 1 and 10. If N is 2 or greater, each measurement point is set at equal intervals along the longitudinal axis x of the coil 11. Next, the coil 11 is placed on the sample stage of the measuring instrument with the coil 11 stretched in a straight line. Using a known universal testing machine, an indenter 50 is pressed against the coil 11 at each measurement point from a direction z perpendicular to the longitudinal axis x at a predetermined speed to an extent of 5% of the outer diameter of the coil 11. The reaction force (in N) applied to the indenter 50 when it is pressed against the coil 11 is measured at each measurement point. If there are 2 or more measurement points N, the average value of the reaction forces measured at multiple measurement points in each section is used for comparison.

[0074] The movement speed of the indenter 50 is not particularly limited, but may be set to, for example, 3 μm / sec or more, 5 μm / sec or more, 30 μm / sec or less, or 25 μm / sec or less.

[0075] A holder or a tubular member through which the coil 11 can be inserted can be used to maintain the coil 11 in a straight line.

[0076] To prevent the coil 11 from shifting position during reaction force measurement, the coil 11 may be fixed to the surface of the sample stage.

[0077] As shown in Figure 4, the indenter 50 used has a disc-shaped portion that contacts the coil 11. The outer diameter 51 of the disc-shaped indenter 50 may be larger than the outer diameter of the coil 11 at the measurement point, but for example, it can be 0.5 times or more the outer diameter of the coil 11 at the measurement point. Alternatively, the outer diameter 51 of the indenter 50 may be 0.7 times or more, 1 time or more the outer diameter of the coil 11 at the measurement point, and can also be set to 3 times or less, 2.7 times or less, or 2.5 times or less the outer diameter of the coil 11 at the measurement point. The material of the indenter is not limited, but for example, it can be made from stainless steel, diamond, sapphire, tungsten carbide (WC), or other cemented carbide.

[0078] As shown in Figures 1 and 5, it is preferable that the coil 11 does not have a portion in the main section 30 where the outer diameter decreases from the distal side to the proximal side. By setting the outer diameter of the main section 30 in this way, it becomes easier to flexibly form the coil 11 from the distal side to the proximal side.

[0079] As shown in Figures 1 and 5, it is preferable that the coil 11 has a first coil section 15 with a constant outer diameter and a second coil section 16 located proximal to the first coil section 15, with a constant outer diameter, and a larger outer diameter overall than the first coil section 15. By providing the first coil section 15 and the second coil section 16 in this way, it becomes easier to flexibly form the coil 11 from the distal side to the proximal side.

[0080] The statement that the outer diameter is constant in the first coil section 15 or the second coil section 16 means that the outer diameter of the coil 11 in that section is substantially constant in the longitudinal axis direction x of the coil 11, and includes cases where the change in the outer diameter of the coil 11 in that section is within ±5%. The same applies to the third coil section 18, the first small diameter section 111, and the second small diameter section 112, which will be described later.

[0081] The outer diameter of the second coil section 16 is preferably 1.02 times or more the outer diameter of the first coil section 15, more preferably 1.05 times or more, and even more preferably 1.08 times or more. Furthermore, the outer diameter of the second coil section 16 may be 1.3 times or less the outer diameter of the first coil section 15, 1.25 times or less, and 1.2 times or less is also acceptable. By setting the outer diameter of the coil 11 in this way, it becomes easier to flexibly form the coil 11 from the distal to the proximal side while ensuring the strength of the coil 11 along the entire longitudinal axis x.

[0082] In the longitudinal axis x of the coil 11, it is preferable that the second coil portion 16 is longer than the first coil portion 15. By setting the length of the second coil portion 16 in this way, the flexibility of the coil 11 can be increased over a wide range in the longitudinal axis x of the coil 11.

[0083] In the longitudinal axis x of the coil 11, the first coil portion 15 may be longer than the second coil portion 16. This allows for a wider area of ​​the coil 11 to have less flexibility in the longitudinal axis x of the coil 11 than the first coil portion 15. For this reason, it can be preferably used in the Framing-Filling process. Note that the lengths of the first coil portion 15 and the second coil portion 16 may be the same in the longitudinal axis x of the coil 11.

[0084] The position of the first coil portion 15 in the longitudinal axis direction x of the coil 11 is not limited. For example, as shown in Figure 5, at least a part of the first coil portion 15 may be located in the distal section 31. In that case, the first coil portion 15 may include the distal end of the distal section 31. Alternatively, the first coil portion 15 may include a portion of the main section 30 that is distal to the longitudinal axis direction x. Although not shown, the first coil portion 15 may be located in both the distal section 31 and the central section 32.

[0085] The first coil section 15 may be located in the central section 32. Alternatively, the first coil section 15 may be located in both the central section 32 and the proximal section 33. Furthermore, the first coil section 15 may be located in the proximal section 33.

[0086] The position of the second coil portion 16 in the longitudinal axis direction x of the coil 11 is not limited, as long as it is located proximal to the first coil portion 15. For example, as shown in Figure 5, at least a portion of the second coil portion 16 may be located in the central section 32. The second coil portion 16 may be located in both the central section 32 and the proximal section 33. The second coil portion 16 may be located in the proximal section 33. In that case, the second coil portion 16 may include the proximal end of the proximal section 33. Also, the second coil portion 16 may include a portion on the proximal end side in the longitudinal axis direction x of the main section 30.

[0087] Although not shown in the diagram, the second coil section 16 may be located in the distal section 31. Alternatively, the second coil section 16 may be located in both the distal section 31 and the central section 32.

[0088] As shown in Figure 5, the first coil section 15 and the second coil section 16 may be arranged adjacent to each other. By arranging sections with different outer diameters adjacent to each other in this way, a bend is more easily formed at the boundary between the first coil section 15 and the second coil section 16 when the coil 11 is placed inside the knot, making it easier to form the coil 11 into a complex shape that is bent in multiple directions.

[0089] As shown in Figure 6, it is preferable that the coil 11 has a first transition section 17 between the first coil section 15 and the second coil section 16, the outer diameter of which decreases toward the distal end. This allows the flexibility of the coil 11 to be gradually increased from the second coil section 16 toward the first coil section 15.

[0090] As shown in Figure 6, the outer diameter of the coil 11 may taper toward the distal end in the first transition section 17. This allows the flexibility of the coil 11 to gradually increase from the second coil section 16 toward the first coil section 15. It also allows the coil 11 to be smoothly inserted into the knot. Here, "tapered" includes a configuration in which the outer diameter of the coil 11 is tapered in the first transition section 17 as a result of the outer diameter of the wire 12 constituting the coil 11 decreasing with each turn. The same applies to the second transition section 19, which will be described later.

[0091] Figure 7 shows a modified example of the first transition section 17. In the first transition section 17, the outer diameter of the coil 11 may decrease in a stepped manner toward the distal end. Here, "stepped" includes a configuration in which the outer diameter of the wire 12 constituting the coil 11 decreases every two or more turns. The same applies to the second transition section 19, which will be described later. In Figure 7, the outer diameter of the coil 11 decreases toward the distal end every three turns in the first transition section 17.

[0092] In the longitudinal axis direction x, the first transition section 17 may be longer than the first coil section 15. Also, in the longitudinal axis direction x, the first transition section 17 may be longer than the second coil section 16. By making the first transition section 17 longer in this way, the flexibility of the coil 11 can be gradually changed over a wide range in the longitudinal axis direction x.

[0093] In the longitudinal axis direction x, the first transition section 17 may be shorter than the first coil section 15. Also, in the longitudinal axis direction x, the first transition section 17 may be shorter than the second coil section 16. By making the first transition section 17 relatively short in this way, the flexibility of the coil 11 can be changed in a short section in the longitudinal axis direction x.

[0094] The first transition section 17 may be located in the distal section 31, the central section 32, or the proximal section 33. Alternatively, the first transition section 17 may be located in both the distal section 31 and the central section 32, or in both the central section 32 and the proximal section 33.

[0095] The shape of the coil 11 in a stationary state without applying external force will be described with reference to Figures 8 to 10. Figure 8 is a schematic diagram showing an example of the shape of the first coil portion of the coil shown in Figure 1 in a stationary state without applying external force. Figure 9 is a schematic diagram showing an example of the shape of the portion between the first coil portion and the second coil portion of the coil shown in Figure 1 in a stationary state without applying external force. Figure 10 is a schematic diagram showing an example of the shape of a part of the main section of the coil of an in-vivo implantation device according to another embodiment of the present invention in a stationary state without applying external force. In order to appropriately position the implantation device 10 at a target site in the body, the linear coil 11 shown in Figure 1 may be shaped to become a complex shape such as a planar shape or a three-dimensional shape.

[0096] When the retaining device 10 is left undisturbed without any external force applied, it is preferable that the first coil section 15 and the second coil section 16 each have a shape that combines a first shape 41 in which the coil 11 forms an annular loop and a second shape 42 in which the coil 11 is curved without forming an annular loop. It is preferable that the portion between the first coil section 15 and the second coil section 16 has a shape that combines only the first shape 41 in which the coil 11 forms an annular loop. By changing the shape of the coil 11 in this way, when the coil 11 is placed in the nodule, the coil 11 curves in multiple directions and becomes a complex shape, making it easier to spread within the nodule, and as a result, the occurrence of nodule rupture or damage can be suppressed.

[0097] The first shape 41 is a shape in which the coil 11 forms a 360-degree circumference when the retaining device 10 is left stationary without any external force being applied. In other words, when observing the extension shape of the coil 11 from the proximal end to the distal end, it means that there is a portion that extends in the opposite direction from the distal end to the proximal end. In contrast, the second shape 42 is a shape in which the coil 11 is curved rather than forming a ring when the retaining device 10 is left stationary without any external force being applied. Figure 8 shows an example of a shape in which the first shape 41 and the second shape 42 are combined, and Figure 9 shows an example of a shape in which only the first shape 41 is combined.

[0098] The second shape 42 includes arcs, waves, meanders, zigzags, spirals (also called two-dimensional helical shapes or spirals), and other random curved shapes that do not involve loops.

[0099] Shapes consisting solely of the first shape 41 include curves (helices) in which the coil 11 extends perpendicular to the circumferential surface while forming an annular loop. Such curves also include helices in which the loop diameter decreases toward the distal or proximal end of the coil 11.

[0100] Shapes formed by combining only the first shape 41 also include shapes in which multiple annular loops are connected and arranged circumferentially. In this case, the direction of the central axes of the multiple interconnected loops may be aligned with the radial direction of the circle having the circumference.

[0101] As shown in Figure 10, when the retaining device 10 is left stationary without any external force applied, the main section 30 of the coil 11 may have three or more curved sections 45. By providing these curved sections 45, it becomes easier to form the coil 11 into a complex shape that is curved in multiple directions.

[0102] The number of curved sections 45 is not particularly limited. The number of curved sections 45 in the main section 30 may be, for example, four or more, five or more, or 20 or fewer, 18 or fewer, or 15 or fewer.

[0103] The coil 11 may form an annular loop by providing three or more curved sections 45 in the main section 30. One or more such loops may be provided in the main section 30. Another part of the coil 11 may pass through the loop in the main section 30.

[0104] By providing three or more curved sections 45 in the main section 30, multiple annular loops may be arranged in a circular pattern. In this case, the direction of the central axes of the multiple interconnected loops may be aligned with the radial direction of the circle having the circumference.

[0105] The presence of the curved section 45 allows the coil 11 to be curved without forming a circular loop. For example, the coil 11 may be curved in an arc shape, a wave shape, or other random shape at the curved section 45.

[0106] Next, with reference to Figures 11 to 13, an in-vivo implantation device 10 according to yet another embodiment of the present invention will be described. Figure 11 is a side view of a coil 11 according to yet another embodiment of the present invention. Figures 12 to 13 are side views showing modified examples of the coil 11 shown in Figure 11.

[0107] In Figure 11, the coil 11 has a first coil section 15, a second coil section 16, and a third coil section 18. More specifically, the coil 11 may have a third coil section 18 that is located more proximal to the second coil section 16, has a constant outer diameter, and has a larger outer diameter overall than the second coil section 16. By providing the third coil section 18 in this way, the flexibility of a single coil 11 can be changed in at least three stages. As a result, even in the later stages of the process of feeding a single coil 11 into the nodule, the coil 11 remains flexible, making it easier to insert and fill the coil 11 smoothly.

[0108] The outer diameter of the third coil section 18 is preferably 1.02 times or more the outer diameter of the second coil section 16, more preferably 1.05 times or more, and even more preferably 1.08 times or more. Furthermore, the outer diameter of the third coil section 18 may be 1.3 times or less the outer diameter of the second coil section 16, 1.25 times or less, and 1.2 times or less is also acceptable. By setting the outer diameter of the coil 11 in this way, it becomes easier to ensure the strength of the coil 11 along the entire longitudinal axis x while ensuring the flexibility of the coil 11 in the proximal section 33.

[0109] The outer diameter of the third coil section 18 is preferably 1.01 times or more the outer diameter of the first coil section 15, more preferably 1.02 times or more, and even more preferably 1.03 times or more. Furthermore, the outer diameter of the third coil section 18 may be 2 times or less the outer diameter of the first coil section 15, 1.8 times or less, and 1.5 times or less is also acceptable. By setting the outer diameter of the coil 11 in this way, it becomes easier to ensure the strength of the coil 11 along the entire longitudinal axis x while ensuring the flexibility of the coil 11 in the proximal section 33.

[0110] In the longitudinal axis x of the coil 11, the third coil portion 18 may be longer than the second coil portion 16. This makes it easier to provide a highly flexible portion of the coil 11 over a wide area in the longitudinal axis x of the coil 11.

[0111] In the longitudinal axis x of the coil 11, the third coil portion 18 may be shorter than the second coil portion 16. This makes it easier to provide a highly flexible portion of the coil 11 over a wide area in the longitudinal axis x of the coil 11. Note that the lengths of the third coil portion 18 and the second coil portion 16 may be the same in the longitudinal axis x of the coil 11.

[0112] In the longitudinal axis x of the coil 11, the third coil portion 18 may be longer than the first coil portion 15. This makes it easier to provide a highly flexible portion of the coil 11 over a wide area in the longitudinal axis x of the coil 11.

[0113] In the longitudinal axis x of the coil 11, the third coil portion 18 may be shorter than the first coil portion 15. This makes it easier to provide a portion of the coil 11 with low flexibility over a wide area in the longitudinal axis x of the coil 11. Note that the lengths of the third coil portion 18 and the first coil portion 15 may be the same in the longitudinal axis x of the coil 11.

[0114] The position of the third coil section 18 in the longitudinal axis x of the coil 11 is not limited, as long as it is located proximal to the second coil section 16. For example, as shown in Figure 11, at least a portion of the third coil section 18 may be located in the proximal section 33. In that case, the third coil section 18 may include the proximal end of the proximal section 33. Alternatively, the third coil section 18 may include a portion of the main section 30 that is on the proximal end side in the longitudinal axis x. The third coil section 18 may be located in both the central section 32 and the proximal section 33.

[0115] The third coil section 18 may be located in the central section 32. Furthermore, the third coil section 18 may be located in both the central section 32 and the distal section 31. Additionally, the third coil section 18 may be located in the distal section 31.

[0116] As shown in Figure 11, the second coil section 16 and the third coil section 18 may be arranged adjacent to each other. By arranging sections with different outer diameters adjacent to each other in this way, a bend is more easily formed at the boundary between the second coil section 16 and the third coil section 18 when the coil 11 is placed inside the knot, making it easier to form the coil 11 into a complex shape that is bent in multiple directions.

[0117] As shown in Figure 11, the first coil section 15, the second coil section 16, and the third coil section 18 may be arranged adjacent to each other. By arranging sections with different outer diameters adjacent to each other in this way, when the coil 11 is placed inside the knot, bends are more easily formed at the boundaries between the first coil section 15 and the second coil section 16, and at the boundaries between the second coil section 16 and the third coil section 18. As a result, it becomes easier to form the coil 11 into a complex shape that is bent in multiple directions.

[0118] As shown in Figure 12, it is preferable that the coil 11 has a second transition section 19 located between the second coil section 16 and the third coil section 18, with its outer diameter decreasing toward the distal end. This allows the flexibility of the coil 11 to be gradually increased from the third coil section 18 toward the second coil section 16.

[0119] In the second transition section 19, the outer diameter of the coil 11 may taper toward the distal end. Alternatively, in the second transition section 19, the outer diameter of the coil 11 may decrease in a stepwise manner toward the distal end. For details on the outer diameter change in the second transition section 19, please refer to the explanation of the first transition section 17.

[0120] In the first transition section 17 and the second transition section 19, the outer diameter of the coil 11 may taper toward the distal end. Alternatively, in the first transition section 17 and the second transition section 19, the outer diameter of the coil 11 may taper toward the distal end. In either the first transition section 17 or the second transition section 19, the outer diameter of the coil 11 may taper toward the distal end, while in the other of the first transition section 17 and the second transition section 19, the outer diameter of the coil 11 may taper toward the distal end.

[0121] In the longitudinal axis direction x, the second transition section 19 may be longer than the second coil section 16. Also, in the longitudinal axis direction x, the second transition section 19 may be longer than the third coil section 18. By making the second transition section 19 longer in this way, the flexibility of the coil 11 can be gradually changed over a wide range in the longitudinal axis direction x.

[0122] In the longitudinal axis direction x, the second transition section 19 may be shorter than the second coil section 16. Also, in the longitudinal axis direction x, the second transition section 19 may be shorter than the third coil section 18. By making the second transition section 19 relatively short in this way, the flexibility of the coil 11 can be changed in a short section in the longitudinal axis direction x.

[0123] The second transition section 19 may be located in the distal section 31, the central section 32, or the proximal section 33. Alternatively, the second transition section 19 may be located in both the distal section 31 and the central section 32, or in both the central section 32 and the proximal section 33.

[0124] As shown in Figure 12, the coil 11 may have, in order from the distal side to the proximal side, a first coil section 15, a first transition section 17, a second coil section 16, a second transition section 19, and a third coil section 18.

[0125] Next, we will describe the shape of the coil 11 when it is left stationary without any external force applied, in the case where the coil 11 has a third coil section 18 in addition to the first coil section 15 and the second coil section 16. When the retaining device 10 is left stationary without any external force applied, it is preferable that the first coil section 15 and the third coil section 18 each have a shape that combines a first shape 41 in which the coil 11 forms an annular loop and a second shape 42 in which the coil 11 is curved without forming an annular loop, and the second coil section 16 has a shape that combines only the first shape 41 in which the coil 11 forms an annular loop. By changing the shape of the coil 11 in the first coil section 15, the third coil section 18 and the second coil section 16 in this way, when the coil 11 is placed in the nodule, the coil 11 is curved in multiple directions and takes on a complex shape, making it easier to spread out in the nodule, and as a result, the occurrence of rupture or damage to the nodule can be suppressed.

[0126] For shapes formed by combining the first shape 41 and the second shape 42, or by combining only the first shape 41, refer to the explanation for the case where the coil 11 has a first coil section 15 and a second coil section 16.

[0127] Next, an in-vivo implantation device according to yet another embodiment of the present invention will be described. The coil 11 may have a fourth coil section located between the first coil section 15 and the second coil section 16, the outer diameter of which changes periodically. When the fourth coil section is inserted into the tumor, the repeating portions in a specific pattern engage with each other, fixing the device in place and making it less prone to deformation. Since the fourth coil section can form the framework of the coil 11, it can be suitably used in procedures that include a framing phase.

[0128] The periodic change in the outer diameter of the coil 11 means that the coils 11 are repeatedly arranged in a specific pattern along the longitudinal axis x. Here, the specific pattern is a pattern in which the outer shape of the coil 11 is a spherical shape, an oblong sphere shape, a hemispherical shape, a semi-oblong sphere shape, a teardrop shape, a polygonal shape, a cone shape, a frustum shape, a linear shape, a cylindrical shape, or a combination thereof, as one unit. Note that the above specific pattern does not include shapes in which the outer diameter of the coil 11 is substantially constant (including those in which the change in the outer diameter of the coil 11 in that part is within a range of ±5%). In other words, the above specific pattern does not include the first coil section 15, the second coil section 16, and the third coil section 18.

[0129] In the longitudinal axis x of the coil 11, it is preferable that the fourth coil portion is longer than the first coil portion 15. By setting the length of the fourth coil portion in this way, it becomes easier to form the framework of the coil 11 to an appropriate size by inserting the coil 11 into the knot.

[0130] In the longitudinal axis x of coil 11, the first coil section 15 may be longer than the fourth coil section. This allows the first coil section 15 to first form the main framework of coil 11, and then the fourth coil section to supplementarily increase the strength of the framework. Note that the lengths of the first coil section 15 and the fourth coil section may be the same in the longitudinal axis x of coil 11.

[0131] The position of the fourth coil portion in the longitudinal axis x of coil 11 is not limited. For example, the fourth coil portion may be located in the distal section 31, the central section 32, or the proximal section 33. Also, the fourth coil portion may be located in the distal section 31 and the central section 32, or in the central section 32 and the proximal section 33.

[0132] The first coil section 15 and the fourth coil section may be arranged adjacent to each other. This makes it easier to perform a procedure in which the first coil section 15 forms the main framework of the coil 11, and then the fourth coil section is used to increase the strength of the framework.

[0133] The fourth coil section and the second coil section 16 may be arranged adjacent to each other. This makes it easier to perform the procedure of first increasing the strength of the frame with the fourth coil section, and then filling the gaps in the frame with the flexible second coil section 16.

[0134] As shown in Figure 13, a first small-diameter section 111, which has a smaller outer diameter than the first coil section 15, may be provided between the first coil section 15 and the second coil section 16. When the coil 11 is placed in the knot, the coil 11 is more easily bent at the first small-diameter section 111, making it easier to form the coil 11 into a complex shape that is bent in multiple directions. In order to improve the ease of inserting the coil 11 into the knot, it is preferable that the first small-diameter section 111 is shorter than the first coil section 15 in the longitudinal axis direction x. It is preferable that the outer diameter of the coil 11 is constant at the first small-diameter section 111.

[0135] As shown in Figure 13, a second small-diameter section 112, having a smaller outer diameter than the second coil section 16, may be provided between the second coil section 16 and the third coil section 18. When the coil 11 is placed in the knot, the coil 11 is more easily bent at the second small-diameter section 112, making it easier to form the coil 11 into a complex shape that is bent in multiple directions. In order to improve the ease of inserting the coil 11 into the knot, it is preferable that the second small-diameter section 112 is shorter than the second coil section 16 in the longitudinal axis direction x. It is also preferable that the second small-diameter section 112 is shorter than the third coil section 18. It is preferable that the outer diameter of the coil 11 is constant in the second small-diameter section 112. The outer diameter of the second small-diameter section 112 may be larger or smaller than that of the first small-diameter section 111, or it may have the same outer diameter as the first small-diameter section 111.

[0136] This application claims the benefit of priority based on Japanese Patent Application No. 2020-168493, filed on October 5, 2020. The entire specification of Japanese Patent Application No. 2020-168493, filed on October 5, 2020, is incorporated herein by reference. [Explanation of Symbols]

[0137] 1: Intra-vivo device delivery system 2: Detachment 3: Pusher 10: Intra-vivo devices 11: Coil 11a: lumen 12: Wire rod 13: Head section 15: First coil section 16: Second coil section 17: 1st transition part 18: Third coil section 19:Second transition part 20: Stretch resistance member 21: Folded section 30: Main section 31: Distal section 32: Central Section 33: Proximal section 41: 1st shape 42:Second shape 45: Curved section 50: Indenter x: Longitudinal axis

Claims

1. A coil having a distal end and a proximal end in the longitudinal axis direction, the head portion provided at the distal end, and the coil having a lumen extending in the longitudinal axis direction, An in-vivo implantation device comprising: an extension resistance member disposed in the lumen of the coil; The coil has a main section that excludes 5% of its longitudinal axial length from both ends, and when the main section is divided into three equal parts, a distal section, a central section, and a proximal section, The average value of the outer diameter of the coil in the central section is less than or equal to the average value of the outer diameter of the coil in the proximal section. The average value of the outer diameter of the coil in the distal section is less than or equal to the average value of the outer diameter of the coil in the central section. The average value of the outer diameter of the coil in the distal section is smaller than the average value of the outer diameter of the coil in the proximal section. The coil comprises a first coil section having a constant outer diameter, and a second coil section located closer to the first coil section, having a constant outer diameter, and having a larger outer diameter overall than the first coil section. A third coil portion is located more proximal to the second coil portion, has a constant outer diameter, and has a larger outer diameter overall than the second coil portion, A first small-diameter portion is located between the first coil portion and the second coil portion and has a smaller outer diameter than the first coil portion, It has a second small-diameter portion located between the second coil portion and the third coil portion, and having a smaller outer diameter than the second coil portion. The proximal end of the first coil and the distal end of the second coil are located in the distal section, The proximal end of the second coil and the distal end of the third coil are located in the central section, With the in-vivo implantation device in a stationary state without applying external force, the first coil portion and the second coil portion each have a shape that combines a first shape in which the coil forms an annular loop and a second shape in which the coil is curved without forming an annular loop. In a state where the in-vivo implantation device is stationary without applying external force, the portion between the first coil portion and the second coil portion has a helix shape in which the coils extend in a direction perpendicular to the circumferential surface while forming an annular loop.

2. The in-vivo implantation device according to claim 1, wherein when a disc-shaped indenter is pressed against the coil from a direction perpendicular to the longitudinal axis at a predetermined speed by an amount equal to 5% of the outer diameter of the coil, the reaction force applied to the indenter in the proximal section is smaller than the reaction force applied to the indenter in the distal section.

3. The in-vivo implantation device according to claim 1 or 2, wherein when a disc-shaped indenter is pressed against the coil from a direction perpendicular to the longitudinal axis at a predetermined speed by an amount equal to 5% of the outer diameter of the coil, the reaction force applied to the indenter in the proximal section is smaller than the reaction force applied to the indenter in the central section.

4. The in-vivo implantation device according to any one of claims 1 to 3, wherein the second coil portion is longer than the first coil portion in the longitudinal axis direction of the coil.

5. The in-vivo implantation device according to any one of claims 1 to 4, wherein the coil has a first transition portion between the first coil portion and the second coil portion, the outer diameter of which decreases toward the distal end.

6. The in-vivo implantation device according to any one of claims 1 to 5, wherein the coil is located between the second coil portion and the third coil portion and has a second transition portion whose outer diameter decreases toward the distal side.

7. The in-vivo implantation device according to any one of claims 1 to 6, wherein the coil is located between the first coil portion and the second coil portion and has a fourth coil portion whose outer diameter changes periodically.

8. The in-vivo implantation device according to claim 7, wherein the fourth coil portion is longer than the first coil portion in the longitudinal axis direction of the coil.

9. The in-vivo implantation device according to any one of claims 1 to 8, wherein, when the in-vivo implantation device is left stationary without any external force being applied, three or more curved sections are provided in the main section of the coil.

10. An in-vivo device according to any one of claims 1 to 9, The coil comprises a pusher detachably connected to the proximal end of the coil, An in-vivo device delivery system in which the outer diameter of the distal end of the pusher is larger than the outer diameter of the proximal end of the coil.

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