Expansion devices

Abstract

To provide an expansion device capable of sufficiently securing work space for executing medical substance transfer work (placing work or recovery work) in a narrow space in a living body.SOLUTION: An expansion device 10A presses a tissue in a living body (parietal pericardium) and forms a work space. The expansion device 10A includes a shaft 18, a support part 20, a balloon 30, and a liquid circulation part 32. The balloon 30 is fixed to a support surface 28. A medical substance M can be placed on the support surface 28 of the support part 20. The balloon 30 can be expanded in a direction in which the support surface 28 is directed by having liquid for expansion introduced inside the balloon 30 from the liquid circulation part 32.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an expansion device.

Background Art

[0002] For example, Patent Document 1 discloses a device for transferring a therapeutic sheet-like substance (medical substance) to a treatment target part in a living body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when trying to place a medical substance on the surface forming a narrow space in a living body (for example, the pericardial cavity, etc.) or recover the medical substance from the narrow space, it may not be possible to sufficiently secure a working space for performing the transfer operation (placement operation or recovery operation).

[0005] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0006] (1) One aspect of the present invention is an expansion device for forming a working space by pressing a tissue in a living body, comprising a shaft, a support portion provided at a tip of the shaft and having a support surface, a balloon fixed to the support surface, and a fluid circulation portion having a lumen through which an expansion fluid for expanding the balloon flows and is connected to the balloon. The medical substance can be placed on the support surface, and the balloon is formed to be expandable in the direction in which the support surface faces when the expansion fluid is introduced from the fluid circulation portion into the balloon.

[0007] (2) The expansion device described in item (1), wherein the support portion extends from the base end of the support portion toward the tip and has a base portion including the support surface, and the balloons are preferably arranged in pairs on both sides of the base portion in the width direction.

[0008] (3) The expansion device described in item (2), wherein the pair of balloons preferably extend parallel to each other along the extending direction of the base portion.

[0009] (4) An expansion device according to any one of items (1) to (3), wherein the shaft is preferably formed in a tubular shape and the fluid flow portion is inserted into the lumen of the shaft.

[0010] (5) An expansion device according to any one of items (1) to (4), comprising an outer cylinder having a lumen through which the shaft is inserted, wherein the support portion is formed in a sheet shape, the support portion and the balloon are housed in the outer cylinder in a curved state by moving the shaft toward the proximal end relative to the outer cylinder, and the support portion and the balloon housed in the outer cylinder are deployed by moving the shaft toward the tip relative to the outer cylinder to expose them from the outer cylinder.

[0011] (6) The expansion device described in item (2), wherein the support portion has a pair of protrusions that protrude from both sides of the base portion in the width direction so as to be inclined in the width direction toward the direction toward the support surface, and the pair of balloons are located between each of the pair of protrusions and the base portion, and when the balloons are expanded, the pair of protrusions are preferably pushed upward toward the direction toward the support surface.

[0012] (7) The expansion device described in item (6), wherein the support portion preferably has a connecting portion that connects the protruding ends of the pair of protruding portions to each other.

[0013] (8) An expansion device according to item (6) or (7), comprising an outer cylinder having a lumen through which the shaft is inserted, wherein the support portion is formed in a sheet shape, and the support portion is housed inside the outer cylinder in a curved shape such that the pair of protrusions come into contact with each other when the shaft is moved in the proximal end direction relative to the outer cylinder. [Effects of the Invention]

[0014] According to the present invention, even when inserting an expansion device into a narrow space within a living body (for example, the pericardial cavity), the balloon can be expanded to push up the tissue within the body in the direction facing the support surface, thereby securing sufficient working space above the support surface. This enables smooth transfer of medical materials. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a perspective view of an expansion device according to a first embodiment of the present invention. [Figure 2] Figure 2 is a plan view of the tip of the extension device shown in Figure 1. [Figure 3] Figure 3 is a longitudinal cross-sectional view along the line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view along the line IV-IV in Figure 2. [Figure 5] Figure 5 is a perspective view showing the balloon in the expanded state in the expansion device shown in Figure 1. [Figure 6] Figure 6 is a flowchart illustrating how to use the expansion device shown in Figure 1. [Figure 7] Figure 7 is an explanatory diagram of the storage process. [Figure 8] Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 7. [Figure 9] Figure 9 is an explanatory diagram of the extension process. [Figure 10] Figure 10 is a perspective view of an expansion device according to a second embodiment of the present invention. [Figure 11]FIG. 11 is a cross-sectional view of the tip of the expansion device of FIG. 10. [Figure 12] FIG. 12 is a perspective view showing the state in which the balloon is expanded in the expansion device of FIG. 10. [Figure 13] FIG. 13 is an explanatory view of the storage process in the method of using the expansion device of FIG. 10. [Figure 14] FIG. 14 is an explanatory view of the expansion process in the method of using the expansion device of FIG. 10. [Figure 15] FIG. 15 is a cross-sectional explanatory view showing a modified example of the support portion of the expansion device of FIG. 10.

Mode for Carrying Out the Invention

[0016] (First Embodiment) As shown in FIG. 1, the expansion device 10A according to the first embodiment of the present invention is used, for example, in the treatment of severe heart failure due to ischemic heart disease. Specifically, the expansion device 10A is used in the treatment of coronary microvascular dysfunction (CMD) that is difficult to treat with coronary intervention using a balloon catheter or a stent. In this case, the expansion device 10A is used to place the medical substance M on the heart 204 that forms the pericardial cavity 202, which is a narrow space (see FIG. 9), or to recover the medical substance M from the heart 204. However, the expansion device 10A may be used to place the medical substance M on the surface that forms a narrow space other than the pericardial cavity 202 or to recover the medical substance M from the surface.

[0017] The medical substance M may be a liquid (including a sol), a solid (including a gel), or a gas. The medical substance M includes, for example, products such as pharmaceuticals, medical devices, and regenerative medicine. Products such as regenerative medicine include cells and exosomes. Specifically, examples of products such as regenerative medicine include sheet-shaped cell cultures or spheroids.

[0018] The sheet-like cell culture may be reinforced by coating it with fibrin or the like. The sheet-like cell culture can be formed by culturing autologous or allogeneic cells. The sheet-like cell culture is, for example, a cell sheet derived from skeletal muscle. The sheet-like cell culture may contain tissue adhesive and local anesthetic. The thickness of the sheet-like cell culture is, for example, about 100 μm, and the diameter of the sheet-like cell culture is, for example, 40 mm. However, the thickness and diameter of the sheet-like cell culture can be set as appropriate.

[0019] As shown in Figure 1, the expansion device 10A comprises a device body 12, an expansion structure 14, and an outer cylinder 16. The device body 12 has a shaft 18 and a support portion 20. The shaft 18 extends in one direction (arrow X direction). The shaft 18 is a cylindrical member having a lumen 19. The lumen 19 opens at the tip of the shaft 18 (end in the direction of arrow X1) and also at the base end of the shaft 18 (end in the direction of arrow X2).

[0020] The shaft 18 is made of, for example, a resin material. The constituent material of the shaft 18 is not particularly limited, but examples include polyamide elastomer, polyester elastomer, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, ABS resin, acrylic resin, polyamide, polyacetal, polybutylene terephthalate, polycarbonate, modified polyphenylene ether, polyether ether ketone, fluororesin, polyimide, polyetherimide, etc. The shaft 18 may also be made of a metal material.

[0021] The shaft 18 may be flexible. The shaft 18 may have a flexible tube portion that can maintain a bent shape. In this case, the shaft 18 can be bent into an appropriate shape within a living organism and maintain that bent shape. The flexible tube portion is formed, for example, by forming the tube wall portion in a bellows shape. However, the flexible tube portion may be made of a material that can maintain a bent shape. Specifically, the flexible tube portion can be formed, for example, by inserting a linear metal member that can maintain a bent shape through the lumen of a resin shaft 18. The flexible tube portion forms only a part of the shaft 18 in the longitudinal direction. However, the flexible tube portion may form the entire shaft 18.

[0022] The support portion 20 is flexible. The support portion 20 is made of, for example, a resin material. The constituent material of the support portion 20 is not particularly limited, but examples include polyethylene terephthalate, polycarbonate, polyamide, polystyrene, polypropylene, polyacetal, polyimide, polyetheretherketone, fluororesin, etc.

[0023] The support portion 20 is formed in a sheet shape. The thickness of the support portion 20 is not particularly limited, but it is preferably set to, for example, 100 μm or more and 200 μm or less.

[0024] As shown in Figures 2 and 3, the support portion 20 has a joint portion 22 and a support body 24. In Figure 3, the joint portion 22 is bonded to the inner circumferential surface of the tip of the shaft 18 with an adhesive. The adhesive is not particularly limited, but examples include UV adhesives and instant adhesives (e.g., cyanoacrylate-based instant adhesives). The joint portion 22 may also be heat-fused to the inner circumferential surface of the shaft 18. When the joint portion 22 is bonded to the inner circumferential surface of the tip of the shaft 18, no step is formed on the outer circumferential surface of the shaft 18 by the joint portion 22, so the shaft 18 can be smoothly inserted into the outer cylinder 16. The joint portion 22 may also be bonded to the outer circumferential surface of the tip of the shaft 18.

[0025] As shown in Figures 2 and 3, the support body 24 includes a base portion 26 extending in one direction (along the direction of arrow X). The base portion 26 extends from the base end of the support portion 20 toward the tip. The base portion 26 has a base end connected to the joint portion 22 and a tip end opposite to the base end. In Figure 2, the base end of the base portion 26 is formed to be wider from the joint portion 22 toward the tip. Both sides of the base end of the base portion 26 in the width direction are tapered toward the joint portion 22. The base portion 26 has a flat support surface 28. A medical substance M can be placed on the support surface 28 (see Figure 1).

[0026] In Figure 1, the expansion structure 14 includes a pair of balloons 30, a fluid flow section 32, and a connector 34. As shown in Figures 1, 2, and 4, the pair of balloons 30 are spaced apart from each other in the width direction perpendicular to the extending direction of the support body 24. The pair of balloons 30 are located on both sides of the support surface 28 in the width direction. Each balloon 30 is fixed (joined) to the support surface 28. The pair of balloons 30 extend parallel to each other along the extending direction of the support body 24. Each balloon 30 expands (inflates) in the direction the support surface 28 faces when expansion fluid is introduced inside it (see Figure 5).

[0027] In Figures 1 and 2, the balloon 30 includes a cylindrical body 36, a first end 38 provided at the tip of the body 36, and a second end 40 provided at the base of the body 36. The body 36 is expandable radially outward. The first end 38 closes the tip opening of the body 36.

[0028] The balloon 30 is made of a stretchable resin material. The constituent material of the balloon 30 is not particularly limited, but examples include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene-propylene-diene rubber, acrylic rubber, fluororubber, urethane rubber, silicone rubber, styrene-based elastomer, olefin-based elastomer, polyester-based elastomer, polyurethane-based elastomer, polyamide-based elastomer, etc. The shape, size, position, etc. of the balloon 30 can be set as appropriate. A pair of balloons 30 may be formed in a U-shape by connecting their base ends to each other. In addition, one or more balloons 30 may be provided on the support surface 28.

[0029] The fluid flow section 32 guides expansion fluid to each balloon 30 for expanding the balloons 30. The fluid flow section 32 includes a pair of expansion tubes 42. Each expansion tube 42 has a lumen 43 through which the expansion fluid flows. One end of the pair of expansion tubes 42 is connected to the second end 40 of the pair of balloons 30, respectively. The other end of the pair of expansion tubes 42 is connected to a connector 34 (see Figure 1). The pair of expansion tubes 42 are inserted into the lumen 19 of the shaft 18.

[0030] The fluid flow section 32 may be joined to the inner circumferential surface of the shaft 18. The fluid flow section 32 may be joined to the outer circumferential surface of the shaft 18 while being passed between the outer cylinder 16 and the shaft 18. The fluid flow section 32 may be configured as a single tube that branches into two midway and connects to each balloon 30.

[0031] In Figure 1, the connector 34 is connected to the base end of the fluid flow section 32. The connector 34 can be connected to a device (e.g., a syringe) capable of injecting and aspirating expansion fluid, and a device (e.g., a check valve) capable of maintaining the expanded state.

[0032] The outer cylinder 16 is a cylindrical member having an inner lumen 17. The inner lumen 17 opens at the tip of the outer cylinder 16 (the end in the direction of arrow X1) and also at the base end of the outer cylinder 16 (the end in the direction of arrow X2). The outer cylinder 16 is flexible. The constituent material of the outer cylinder 16 is the same as the constituent material of the shaft 18 described above. If the shaft 18 has a flexible tube section, the outer cylinder 16 bends along the curved shape of the shaft 18. In this embodiment, the outer cylinder 16 may also have a flexible tube section as described above. In this case, the shaft 18 does not need to have a flexible tube section.

[0033] A shaft 18 is inserted through the lumen 17 of the outer cylinder 16. The total length of the outer cylinder 16 is shorter than the total length of the shaft 18. In Figures 2 and 3, the inner diameter D of the outer cylinder 16 is smaller than the width W of the middle section of the base section 26. The width W of the middle section of the base section 26 is set to a length that allows the support section 20 to be housed inside the outer cylinder 16 in a cylindrical shape along the circumferential direction of the inner surface of the outer cylinder 16 (see Figure 8).

[0034] Valve bodies (not shown) are provided at the base end of the outer cylinder 16 and the base end of the shaft 18. This prevents, for example, the inside of the body from communicating with the outside of the body through the lumen 17 of the outer cylinder 16 or the lumen 19 of the shaft 18.

[0035] Next, the method of using the expansion device 10A will be described. As shown in Figure 6, this method of use includes a medical material placement step, a storage step, a placement step, a deployment step, an expansion step, a transfer step, and a removal step.

[0036] First, in the medical material placement process (step S1), the medical material M is placed on the support surface 28 of the support part 20. Then, in the storage process (step S2), the support part 20 and the medical material M are stored inside the outer cylinder 16. Specifically, the shaft 18 and the fluid flow section 32 are moved in the base direction relative to the outer cylinder 16.

[0037] As a result, the support portion 20 is pulled in from the tip opening of the outer cylinder 16 toward the base end. At this time, the tapered sides of both sides of the base end of the base portion 26 come into contact with the tip surface of the outer cylinder 16, causing a force to act on the base end of the base portion 26, causing it to curl along the circumferential direction of the outer cylinder 16. Therefore, the base end of the base portion 26 is smoothly pulled into the outer cylinder 16 while curling.

[0038] When the base end of the base portion 26 deforms, a force acts on the middle portion of the base portion 26 that causes it to curl along the circumferential direction of the outer cylinder 16, so the middle portion of the base portion 26 is pulled into the outer cylinder 16 while curling. As a result, the base portion 26 deforms into a cylindrical shape along the inner surface of the outer cylinder 16. The medical material M is housed inside the outer cylinder 16 in a shape that corresponds to the shape of the base portion 26 (see Figure 8). The storage process is completed when the entire support portion 20 and the medical material M are completely housed inside the outer cylinder 16, as shown in Figure 7.

[0039] Next, in the placement process (step S3 in Figure 6), the expansion device 10A is inserted into the thoracic cavity (in vivo) through the incision in the chest, and then the expansion device 10A is inserted into the pericardial cavity 202 through the incision in the parietal pericardium 200. At this time, the tip of the expansion device 10A is positioned near the surface of the heart 204 (the area to be treated).

[0040] Subsequently, in the deployment process (step S4), the support portion 20 and the medical material M are deployed. Specifically, in the deployment process, the shaft 18 and the fluid flow portion 32 are moved toward the tip relative to the outer cylinder 16. As a result, the support portion 20, which is exposed from the tip opening of the outer cylinder 16, returns to its original shape due to the restoring force. When the support portion 20 is deployed, the medical material M spreads out into a planar shape. At this time, the support surface 28 is facing the parietal pericardium 200.

[0041] Next, in the expansion step (step S5), the pair of balloons 30 are expanded as shown in Figure 9. That is, expansion fluid is introduced into each balloon 30 from the connector 34 via a pair of expansion tubes 42. As a result, each balloon 30 expands (inflates) in the direction that the support surface 28 is facing (the direction in which the parietal pericardium 200 is located). Therefore, the pair of balloons 30 push the parietal pericardium 200 upward in the direction away from the heart 204. This creates a wide working space 206 above the support surface 28.

[0042] Then, in the transfer process (step S6 in Figure 6), the medical substance M placed on the support surface 28 is transferred to the surface of the heart 204 using forceps or the like (not shown). At this time, since a wide working space 206 is secured by the balloon 30, the transfer of the medical substance M can be carried out efficiently.

[0043] Subsequently, in the removal process (step S7), the expansion fluid is aspirated from inside each balloon 30 to deflate the balloon 30, and the expansion device 10A is removed from the body with the support portion 20 housed inside the outer cylinder 16.

[0044] Furthermore, the expansion device 10A can also be used to recover medical material M from within a living body. In this case, the medical material placement step described above is not performed. In the transfer step, the medical material M placed (attached) to the surface of the heart 204 is transferred to the support surface 28 using forceps or the like (not shown). At this time, the medical material M may be placed on the support surface 28 by sliding the base part 26 between the medical material M and the heart 204 without using forceps or the like. The expansion device 10A is not limited to use in thoracoscopic or laparoscopic surgery, but may also be used in open chest surgery or open abdominal surgery.

[0045] This embodiment provides the following effects.

[0046] According to this embodiment, even when inserting the expansion device 10A into a narrow space within the body (for example, the pericardial cavity 202), the balloon 30 can be expanded to push up the tissue within the body (parietal pericardium 200) in the direction facing the support surface 28, thereby securing sufficient working space 206 above the support surface 28. This enables smooth transfer of the medical substance M.

[0047] The support portion 20 has a base portion 26 that extends from the base end toward the tip and includes a support surface 28. A pair of balloons 30 are arranged on both sides of the base portion 26 in the width direction.

[0048] With this configuration, it becomes easier to create a wide working space 206 above the support surface 28 of the base portion 26.

[0049] The pair of balloons 30 extend parallel to each other along the direction of extension of the base portion 26.

[0050] With this configuration, the working space 206 can be formed along the extending direction of the base portion 26.

[0051] The shaft 18 is formed in a tubular shape, and the fluid flow section 32 is inserted into the lumen 19 of the shaft 18.

[0052] With this configuration, the expansion device 10A can be made more compact compared to the case where the fluid flow section 32 is located outside the shaft 18.

[0053] The expansion device 10A comprises an outer cylinder 16 having a lumen 17 through which a shaft 18 is inserted. The support portion 20 is formed in a sheet shape. The support portion 20 and balloon 30 are housed inside the outer cylinder 16 in a curved state by moving the shaft 18 toward the proximal end relative to the outer cylinder 16. The support portion 20 and balloon 30 housed inside the outer cylinder 16 are deployed by moving the shaft 18 toward the tip relative to the outer cylinder 16, exposing them from the outer cylinder 16.

[0054] With this configuration, the support part 20 can be compactly housed inside the outer cylinder 16.

[0055] (Second Embodiment) Next, an expansion device 10B according to a second embodiment of the present invention will be described. In this embodiment, components identical to those of the expansion device 10A described above are given the same reference numerals and detailed descriptions are omitted. Furthermore, in this embodiment, components identical to those of the expansion device 10A described above have the same effects and advantages.

[0056] As shown in Figure 10, the device body 12a of the extension device 10B is equipped with a support portion 20a in place of the support portion 20 described above. The support body 24a of the support portion 20a has a joint portion 22, a base portion 26, a pair of first protrusions 60, and a pair of second protrusions 62. The pair of first protrusions 60 project from both sides in the width direction of the intermediate portion of the base portion 26 in the extending direction, inclined inward in the width direction toward the direction (upward) toward the support surface 28. The pair of second protrusions 62 are each connected to the tips of the pair of first protrusions 60. The pair of second protrusions 62 project from both sides in the width direction of the base portion 26 inclined outward in the width direction toward the direction (upward) toward the support surface 28.

[0057] As shown in Figures 10 and 11, the pair of balloons 30 are positioned adjacent to the pair of first protrusions 60 in the width direction of the base portion 26. The balloons 30 are located between each of the pair of first protrusions 60 and the base portion 26. That is, the balloons 30 are covered from above by the first protrusions 60. The balloons 30 expand with the expansion fluid, pushing up the first protrusions 60 in the direction that the support surface 28 faces (see Figures 12 and 14).

[0058] In this embodiment, when the support portion 20a and the medical material M are housed inside the outer cylinder 16, as shown in Figure 13, the outer surfaces of the pair of first protrusions 60 are in contact with each other, and the outer surfaces of the pair of second protrusions 62 are in contact with each other. The protruding end faces of the pair of second protrusions 62 are spaced apart from the medical material M.

[0059] Furthermore, in this embodiment, when expansion fluid is introduced into each balloon 30 during the expansion process, as shown in Figure 14, the pair of balloons 30 push up the parietal pericardium 200 in the direction opposite to the heart 204 via the pair of first protrusions 60. At this time, the pair of first protrusions 60 tilt so that the angle between the first protrusions 60 and the base portion 26 widens. In other words, the pair of first protrusions 60 push up the parietal pericardium 200 outward in the width direction of the base portion 26. As a result, a working space 206 can be efficiently formed above the support surface 28.

[0060] In this embodiment, the support portion 20a has a pair of first protrusions 60 that project inward in the width direction from both sides of the base portion 26 toward the direction toward the support surface 28. The balloon 30 is positioned between each of the pair of first protrusions 60 and the base portion 26, and when the balloon 30 expands, it pushes the pair of first protrusions 60 upward toward the direction toward the support surface 28.

[0061] With this configuration, the tissue located in the direction that the support surface 28 faces (parietal pericardium 200) can be pushed up toward the widthwise outward direction of the base portion 26 by the pair of first protrusions 60, thereby efficiently forming a working space 206 above the support surface 28.

[0062] The support portion 20a is housed inside the outer cylinder 16 in a curved shape, caused by moving the shaft 18 in the base end direction relative to the outer cylinder 16, so that the pair of first protrusions 60 come into contact with each other.

[0063] With this configuration, the width dimension of the support surface 28 can be made relatively large while the support part 20a can be compactly housed inside the outer cylinder 16.

[0064] This embodiment is not limited to the configuration described above. As shown in Figure 15, the support portion 20a may have a connecting portion 70 that connects the protruding ends of a pair of first protrusions 60 to each other. The connecting portion 70 is joined to the protruding ends of the pair of first protrusions 60. The connecting portion 70 is made of an expandable material (e.g., rubber) so that the pair of first protrusions 60 can tilt outward in the width direction of the base portion 26 when the balloon 30 is expanded. However, the constituent material of the connecting portion 70 can be set as appropriate. The connecting portion 70 may be integrally molded with the pair of first protrusions 60.

[0065] In this modified example, the support portion 20a has a connecting portion 70 that connects the protruding ends of a pair of first protrusions 60 to each other. With this configuration, the tissue located above the support surface 28 (parietal pericardium 200) can be supported by the connecting portion 70, thus allowing for a more efficient formation of the working space 206.

[0066] Furthermore, the present invention is not limited to the disclosure described above, and can take various configurations without departing from the spirit of the invention. [Explanation of Symbols]

[0067] 10A, 10B... Expansion devices 16... Outer cylinder 18... Shaft 20, 20a... Support part 26...Base section 28...Support surface 30...Balloon 32...Fluid flow section 60...First protruding part (protruding part) 70...Connecting part 206…Workspace M…Medical materials

Claims

1. An expansion device for forming a workspace by pressing on tissue within a living organism, The shaft and A support portion having a support surface is provided at the tip of the shaft, A balloon fixed to the aforementioned support surface, The device comprises a fluid flow section connected to the balloon and having a lumen through which an expansion fluid for expanding the balloon flows, Medical materials can be placed on the aforementioned support surface. The balloon is an expansion device formed to be expandable in the direction the support surface faces by introducing the expansion fluid into the balloon from the fluid flow section.

2. An expansion device according to claim 1, The support portion extends from the base end toward the tip and has a base portion including the support surface. The balloons are expansion devices arranged in pairs on both sides of the base portion in the width direction.

3. An expansion device according to claim 2, An expansion device in which a pair of balloons extend parallel to each other along the extending direction of the base portion.

4. An expansion device according to claim 1, The shaft is formed in a tubular shape, The fluid flow section is an expansion device inserted into the lumen of the shaft.

5. An expansion device according to any one of claims 1 to 4, The outer cylinder has an inner lumen through which the shaft is inserted, The support portion is formed in a sheet shape, The support portion and the balloon are housed inside the outer cylinder in a curved state by moving the shaft toward the base end relative to the outer cylinder. An expansion device in which the support portion and the balloon housed within the outer cylinder are deployed by moving the shaft toward the tip relative to the outer cylinder, thereby exposing them from the outer cylinder.

6. An expansion device according to claim 2, The support portion has a pair of protrusions that project inward in the width direction from both sides of the base portion in the width direction toward the direction toward the support surface, An expansion device in which a pair of balloons are positioned between each of the pair of protrusions and the base, and when the balloons are expanded, the pair of protrusions are pushed upward in the direction toward the support surface.

7. An expansion device according to claim 6, The support portion is an extension device having a connecting portion that connects the protruding ends of the pair of protruding portions to each other.

8. An expansion device according to claim 6 or 7, The outer cylinder has an inner lumen through which the shaft is inserted, The support portion is formed in a sheet shape, The support portion is an expansion device housed inside the outer cylinder in a curved state, where the pair of protrusions come into contact with each other by moving the shaft in the base end direction relative to the outer cylinder.

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