Body fluid recirculation device

Abstract

A tubular main body part (10) of a liquid recirculation device 1 has a first end part (10a) that is provided inside an abdominal cavity organ (2) and a second end part (10b) that is provided inside the abdominal cavity (3). The first end part is provided with a valve (13) having liquid outlet (13c) on the downstream side in the direction of flow of a liquid. The liquid recirculation device (1) outputs liquid, which is inside the abdominal cavity (3) and which flows into the second end part, from the outlet (13c) of the valve (13), so as to recirculate the liquid into the abdominal cavity organ (2).

Description

Technical Field

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[0001] The present invention relates to a body fluid reflux device.

Background Art

[0002] Conventionally, as one of the treatment methods for ascites stored in the abdominal cavity, a peritoneal venous shunt procedure is known. In the peritoneal venous shunt procedure, a flow path connecting the abdominal cavity and the vein is formed by a catheter, a stent, or the like, and ascites is refluxed into the blood vessel by utilizing the pressure difference between the intra-abdominal pressure and the venous pressure.

[0003] For example, Patent Document 1 discloses a peritoneal venous shunt catheter that is implanted in the body so as to pass through the liver from the right subclavian vein through the right atrium, the vena cava, and the right hepatic vein and reach the abdominal cavity, and has a backflow prevention valve. Further, Patent Document 2 discloses a peritoneal venous shunt stent having a valve that is disposed at one end in the intrahepatic vein, penetrates the liver parenchyma, and is disposed at the other end in the abdominal cavity and opens and closes according to the pressure difference between the abdominal cavity and the intrahepatic vein.

Prior Art Documents

Patent Documents

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The peritoneal venous shunt catheter as shown in Patent Document 1 is a long catheter that is ind留置ed over a wide range from the subclavian vein to the abdominal cavity. Therefore, the burden on the patient is large during the operation or the like.

[0006] On the other hand, stents for peritoneal venous shunts, such as those shown in Patent Document 2, are placed via a relatively short route from an intrahepatic vein through the liver parenchyma to the abdominal cavity. However, if the accumulated ascites fluid is returned to the blood vessels, there is a risk of serious complications such as heart failure and increased susceptibility to thrombus formation.

[0007] Therefore, the present invention has been made in view of these problems, and aims to provide a fluid recirculation device that can recirculate bodily fluids such as ascites into the body in a relatively minimally invasive manner while suppressing the onset of serious complications. [Means for solving the problem]

[0008] One aspect of the present invention is a body fluid recirculation device comprising a cylindrical main body. The main body has a first end located at one axial end that is disposed within the abdominal organs, and a second end located at the other end that is disposed within the abdominal cavity. The first end is provided with a valve having a body fluid outlet on the downstream side in the direction of body fluid flow. The valve section comprises a first valve section connected to the main body and a second valve section covering the first valve section from the outside. The fluid recirculation device returns fluid from the abdominal cavity, which flows in from the second end, to the abdominal organs by draining it out through the valve outlet. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a fluid recirculation device that can recirculate bodily fluids such as ascites into the body in a relatively minimally invasive manner while suppressing the onset of serious complications. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of the configuration of the body fluid recirculation device according to this embodiment. [Figure 2] This is a schematic diagram showing the usage status of a body fluid recirculation device. [Figure 3] (a) is a diagram showing a portion of one end of the fluid return device in an indwelling state, and (b) is a diagram showing the valve portion at one end of the fluid return device. [Figure 4](a) is a diagram showing the fluid recirculation device from the other end, (b) is a cross-sectional view of IVb-IVb in Figure 4(a), and (c) is a cross-sectional view of IVc-IVc in Figure 4(a). [Figure 5] This figure shows a modified example 1 of the body fluid recirculation device according to this embodiment. [Figure 6] This figure shows a modified example 2 of the body fluid recirculation device according to this embodiment. [Figure 7] This figure shows a modified example 3 of the body fluid recirculation device according to this embodiment. [Figure 8] This is a perspective view showing a modified example 4 of the body fluid recirculation device of this embodiment. [Figure 9] This is a cross-sectional view taken along line IX-IX in Figure 8. [Modes for carrying out the invention]

[0011] The following describes an example of the configuration of a body fluid recirculation device according to an embodiment of the present invention, with reference to the drawings. Here, the shapes and dimensions of each part in the drawings are schematic representations and do not represent the actual shapes and dimensions. In the drawings, the axial direction Ax of the body fluid return device is indicated by an arrow as needed. The direction approximately perpendicular to the axial direction Ax is defined as the radial direction. Where necessary, one end of the body fluid return device is indicated by the symbol F and the other end by the symbol B in the drawings.

[0012] Figure 1 shows an example of the configuration of the body fluid return device 1. Figure 2 is a schematic diagram showing the body fluid return device 1 in use. Figure 3(a) shows a portion of one end of the body fluid return device 1 in the implanted state, and Figure 3(b) shows the valve portion at one end of the body fluid return device 1. Figure 4(a) shows the body fluid return device 1 from the other end, Figure 4(b) is a cross-sectional view of IVb-IVb in Figure 4(a), and Figure 4(c) is a cross-sectional view of IVc-IVc in Figure 4(a).

[0013] The body fluid reflux device 1 is a device with a cylindrical overall shape. The body fluid reflux device 1 is used to reflux ascites (body fluid) that is excessively stored in the abdominal cavity and contains useful components such as white blood cells and proteins to the abdominal organ 2 (for example, the stomach). As shown in FIGS. 2 and 3(a), the body fluid reflux device 1 is inserted and retained in the opening 2b formed in the wall 2a of the abdominal organ 2. One end side of the body fluid reflux device 1 is the downstream side in the flow direction of the body fluid and is disposed inside the abdominal organ 2. The other end side of the body fluid reflux device 1 is the upstream side in the flow direction of the body fluid and is disposed in the abdominal cavity 3. Examples of the abdominal organ 2 include digestive organs and digestive tracts such as the stomach, duodenum, small intestine, and large intestine, but this is just an example and is not limited thereto.

[0014] As shown in FIG. 1, the body fluid reflux device 1 includes a cylindrical main body part 10 whose one end side and the other end side in the axial direction Ax communicate with each other, and a first locking part 20 and a second locking part 30 as an example of a positioning part. In the retained state shown in FIGS. 2 and 3(a), the internal space of the main body part 10 forms a flow path through which the body fluid can pass from the other end side toward the one end side. Note that the dimensions of the main body part 10 in the axial direction Ax and the radial direction can be appropriately adjusted within a range that can guide the body fluid stored in the abdominal cavity 3 into the abdominal organ 2 without imposing an excessive load on the patient's body.

[0015] The main body part 10 has a cylindrical skeleton part 11 and a coating part 12 fixed to the skeleton part 11. Further, the main body part 10 has a valve part 13 at the first end part 10a on one end side in the axial direction Ax, and an inflow assisting part 14 at the second end part 10b on the other end side in the axial direction Ax. In the present embodiment, the skeleton part 11 is disposed in the main body part 10 except for the flat region on the tip side of the valve part 13.

[0016] The skeleton part 11 has a so-called self-expanding structure in which the shape in the expanded state is memorized, and can expand and contract from the contracted state contracted to the inner side in the radial direction to the expanded state expanded to the outer side in the radial direction. Although not shown in the figure, the body fluid reflux device 1 is housed in a sheath in the state contracted to the inner side in the radial direction (not shown) and is introduced into the patient's body through an endoscopic ultrasonography (EUS).

[0017] The skeleton part 11 is, for example, formed by knitting a wire made of a metal wire into a fence shape. Examples of the material of the wire of the skeleton part 11 include known metals or metal alloys typified by Ni-Ti alloys, stainless steels, titanium alloys, etc. Note that the skeleton part 11 may be formed of a material other than metal (for example, ceramic, resin, etc.).

[0018] Also, an alloy material having X-ray contrast may be used for the wire of the skeleton part 11, or a marker piece (not shown) formed of an alloy material having X-ray contrast may be appropriately attached to the wire. In these cases, the position of the body fluid reflux device 1 can be confirmed from outside the body.

[0019] When a Ni-Ti alloy is used as the material constituting the skeleton part 11, after arranging the skeleton part 11 in the shape of the expanded state, by performing a predetermined heat treatment, the shape of the expanded state can be memorized in the skeleton part 11.

[0020] Note that the configuration of the skeleton part 11 is not limited to the above. For example, the metal wire may be knitted in a lattice shape or a spiral shape by other knitting methods to form the skeleton part 11. Alternatively, a thin-walled cylindrical body made of the various metals described above may be laser-cut to form the skeleton part 11 such as a pattern in which the metal thin wire is wound in a spiral shape while being zigzag folded.

[0021] The coating part 12 is a tubular flexible film body that forms the above-described flow path, and is attached to the skeleton part 11 so as to close the gap part of the skeleton part 11. In the present embodiment, as shown in FIGS. 4(b) and (c), the coating part 12 is attached to the outer peripheral side of the skeleton part 11. The method of fixing the coating part 12 to the skeleton part 11 may be any of, for example, formation of a coating by dipping, sewing with a thread, adhesion, welding, sticking with a tape, etc.

[0022] The coating portion 12 is used in an environment where it is exposed to digestive fluids (e.g., gastric juice) of the abdominal organs 2, and is therefore formed from a material that is acid-resistant and biocompatible. Examples of materials for the coating portion 12 include fluororesins such as PTFE (polytetrafluoroethylene) and polyethylene resins such as ultra-high molecular weight polyethylene. Ultra-high molecular weight polyethylene is polyethylene with a molecular weight of 1 to 7 million.

[0023] In the body fluid recirculation device 1, the valve portion 13 at one end is continuously covered by the membrane body of the cap portion 12 from the valve portion 13 at one end to the second end portion 10b at the other end. As a result, the portion that faces the opening 2b of the wall 2a of the abdominal organ 2 when placed and passes through the wall 2a of the abdominal organ 2 (for example, the region between the first locking portion 20 and the second locking portion 30), and the portion that is positioned downstream within the abdominal organ 2 (the region from the first locking portion 20 to the valve portion 13), are both integrally formed as a flow path with an acid-resistant and biocompatible membrane body.

[0024] Furthermore, the coating portion 12 may have different physical properties depending on the part of the membrane, for example, by having acid-resistant membranes in the part that passes through the wall 2a of the abdominal organ 2 and the part downstream that is disposed within the abdominal organ 2, while the membranes disposed elsewhere do not have acid-resistant properties.

[0025] The valve section 13 is a backflow prevention valve and is responsible for preventing the backflow of bodily fluids from one end. Furthermore, the valve portion 13 is formed by covering a pair of extensions 11a, 11a extending toward the outlet 13c with the film of the coating portion 12. The pair of extensions 11a, 11a are made from parts of the metal wires that make up the skeletal portion 11, and are arranged to face each other across the tube axis of the main body portion 10, with the heights of the two radially opposing peaks of the main body portion 10 being higher than the heights of the other peaks.

[0026] The valve portion 13 is formed in a tapered shape, with the flow path cross-sectional area at one end being smaller than the flow path cross-sectional area at the other end. The valve portion 13 has a tapered portion 13a and a flat portion 13b, extending from the other end towards the one end.

[0027] The tapered portion 13a is formed such that the dimension in the first direction D1, which is perpendicular to the axial direction Ax, is almost constant, and the dimension in the second direction D2, which is approximately perpendicular to the axial direction Ax and the first direction D1, narrows as it moves from one end to the other. In other words, in the tapered portion 13a, the flow path cross-sectional area gradually decreases from one end to the other. The first direction D1 and the second direction D2 are shown in Figure 3(b).

[0028] Furthermore, the flat portion 13b is formed in a flattened shape in which the dimensions in the first direction D1 and the second direction D2 are maintained along the axial Ax, and the membrane body is almost in close contact in the second direction D2. In addition, an outlet 13c is formed at one end of the flat portion 13b to allow body fluid to flow out into the abdominal organs 2.

[0029] When no body fluid is flowing through the body fluid return device 1, the flat portion 13b extends linearly in the first direction D1, and the membrane body adheres tightly in the second direction D2, maintaining a closed state at the outlet 13c. On the other hand, when body fluid is flowing through the body fluid return device 1, the flat portion 13b is pushed open by the internal pressure of the body fluid, causing the membrane body to separate in the second direction D2, and the outlet 13c to open.

[0030] As described above, the valve 13 allows the discharge of body fluid from the outlet 13c into the abdominal organs 2, while suppressing the backflow of body fluid, including digestive fluid, from the abdominal organs 2 to the body fluid return device 1. The outlet 13c opens in an elliptical or rectangular shape when discharging body fluid, but the opening shape of the outlet 13c is not particularly limited as long as it is a shape that allows body fluid to pass through.

[0031] The inflow assist section 14 has a structure that allows bodily fluids to flow in from the side of the main body 10 and plays the function of assisting the inflow of bodily fluids into the main body 10. For example, the inflow assist section 14 is provided with a number of through holes 14a that penetrate the coating section 12 inward and outward. The through holes 14a of the inflow assist section 14 are formed to a size that allows components of bodily fluids (e.g., proteins) to pass through. The size and shape of the through holes 14a can be changed as appropriate, and a detailed explanation is omitted here. Alternatively, for example, the opening 15 at the second end 10b of the main body 10 may be covered with the coating section 12, and the through holes 14a may be formed in the covered portion.

[0032] In the fluid recirculation device 1, when the pressure inside the abdominal organs 2 is lower than the internal pressure of the abdominal cavity 3 which is expanded with body fluid, body fluid flows into the main body 10 through the opening 15 at the second end 10b of the main body 10, and also through the through-hole 14a of the inflow assist part 14. This makes it possible to efficiently guide the body fluid from the abdominal cavity 3 into the abdominal organs 2 via the fluid recirculation device 1.

[0033] Furthermore, even if the opening 15 at the second end 10b of the main body 10 is temporarily blocked due to changes in the patient's posture, such as turning over in bed, body fluid can still be allowed to flow into the main body 10 through the through-hole 14a of the inflow assist unit 14. This reduces the possibility that the flow of body fluid into the abdominal organs 2 by the body fluid return device 1 may be obstructed, even during treatment.

[0034] The first locking portion 20 is provided in an annular shape on the outer circumference of the main body portion 10 and is positioned at an axial distance from the valve portion 13 toward the other end. Furthermore, the first locking portion 20 has a skeletal portion 21, and the metal skeleton has a shape that widens and protrudes outward from one end to the other. The skeletal portion 21 may be formed separately from the skeletal portion 11 of the main body portion 10, for example, and attached to the main body portion 10 by sewing, crimping, or the like. Alternatively, the skeletal portion 21 may be formed integrally with the skeletal portion 11 of the main body portion 10, for example, using the same wire material.

[0035] The first locking portion 20 is positioned inside the abdominal organ 2 when placed, and when an external force acts to displace the fluid return device 1 toward the other end, it catches on the inner surface of the wall 2a of the abdominal organ 2, thereby preventing the fluid return device 1 from coming out of the abdominal organ 2 and suppressing its deviation into the abdominal cavity 3.

[0036] The second locking portion 30 is provided in an annular shape on the outer circumference of the main body portion 10, similar to the first locking portion 20, and is positioned axially apart from the first locking portion 20 at the other end. The distance between the first locking portion 20 and the second locking portion 30 is appropriately set to allow the wall 2a of the abdominal organ 2 to fit between the first locking portion 20 and the second locking portion 30.

[0037] The second locking portion 30 has a skeletal portion 31 and a cover 32 that covers the entire skeletal portion 31. The skeletal portion 31 consists of a flange-shaped metal skeleton in which wires, each folded back so as to be convex on the outer circumference, are arranged in a ring shape in the circumferential direction of the main body portion 10. The skeletal portion 31 has a shape in which it rises outward from both the one end and the other end in the axial direction Ax as it moves towards the axial center.

[0038] The skeletal portion 31 may be formed separately from the skeletal portion 11 of the main body portion 10, similar to the skeletal portion 21 of the first locking portion 20, and may be attached to the main body portion 10 by sewing, crimping, or the like. Alternatively, the skeletal portion 31 may be formed integrally with the skeletal portion 11 of the main body portion 10 using the same wire material.

[0039] The cover 32 of the second locking portion 30 is made of a thin film material that is biocompatible and elastically deformable to follow the deformation of the skeletal portion 31. Examples of materials for the cover 32 include silicon, which may be used in sheet form or formed by dipping or the like. Furthermore, the cover 32 does not need to cover the entire skeletal portion 31; for example, it may be configured to cover only the portion of the skeletal portion 31 that is on the stomach wall side (the side that contacts the stomach wall).

[0040] The cover 32 is attached to the metal skeleton of the skeletal part 31 so as to close off the gaps in the skeletal part 31. The cover 32 serves to prevent the intrusion of cellular tissue into the inside of the skeletal part 31 in order to facilitate the removal of the body fluid perfusion device 1 after treatment. The method of fixing the cover 32 to the skeletal part 31 may be any of the following: suturing, bonding, welding, etc.

[0041] The second locking portion 30 (particularly the skeletal portion 31) is positioned outside the abdominal organ 2 when the device is placed, and together with the first locking portion 20 (skeletal portion 21), it clamps the wall 2a of the abdominal organ 2 to suppress axial displacement (migration) of the fluid return device 1. In addition, the second locking portion 30 (particularly the skeletal portion 31) also has the function of preventing the fluid return device 1 from protruding into the abdominal organ 2 by catching on the outer surface of the wall 2a of the abdominal organ 2 when an external force that displaces the fluid return device 1 toward one end is applied to it.

[0042] The radial dimension of the second locking portion 30 may be the same as or different from the radial dimension of the first locking portion 20. For example, when considering the ease of removal of the body fluid recirculation device 1 by pulling it from the abdominal organ 2 side, it is preferable that the radial dimension of the second locking portion 30 be smaller than the radial dimension of the first locking portion 20.

[0043] Next, the procedure for implanting the fluid perfusion device 1 in the abdominal organs 2 will be described. The procedure for implanting the fluid perfusion device 1 is performed, for example, endoscopically, but this is just one example and is not limited to this. First, in order to insert the fluid recirculation device 1, an opening 2b is formed in the wall 2a of the abdominal organs 2 by, for example, incision or puncture using an endoscope ultrasound. The size of the opening 2b in the abdominal organs 2 is set appropriately according to the dimensions of the main body 10 of the fluid recirculation device 1.

[0044] Then, a catheter (not shown) housed in a cylindrical sheath is inserted through the opening described above, with the fluid return device 1, which has been contracted radially inward, inside it. Subsequently, with the wall 2a of the abdominal organ 2 positioned between the first locking portion 20 and the second locking portion 30 of the fluid return device 1 in the axial direction Ax, the catheter sheath is moved to withdraw it. As a result, the fluid return device 1 is released from the sheath. At this time, the first end 10a of the fluid return device 1 is positioned inside the abdominal organ 2, and the second end 10b of the fluid return device 1 is positioned inside the abdominal cavity 3.

[0045] The fluid return device 1 self-expands radially outward as it is released from its sheath. As a result, the expanded main body 10 presses against the wall 2a, widening the opening 2b of the abdominal organ 2, and the gap between the abdominal organ 2 and the fluid return device 1 is closed. Alternatively, an expansion catheter (not shown), different from the indwelling catheter, may be inserted inside the fluid return device 1, and the fluid return device 1 may be expanded radially outward by the expansion of the expansion catheter.

[0046] Furthermore, the first locking portion 20 of the fluid return device 1 expands radially beyond the opening inside the abdominal organ 2, and the second locking portion 30 expands radially beyond the opening outside the abdominal organ 2. As a result, the wall 2a of the abdominal organ 2 is sandwiched from both the inside and outside by the first locking portion 20 and the second locking portion 30. Therefore, even if external forces such as peristalsis of the abdominal organ 2 or changes in the patient's posture such as turning over act on the fluid return device 1, the fluid return device 1 is less likely to shift position in the axial direction Ax relative to the abdominal organ 2.

[0047] Furthermore, if an external force is applied to the fluid recirculation device 1 to displace it toward the other end, the first locking portion 20 catches on the inner surface of the wall 2a of the abdominal organ 2, resisting the force in the direction of displacement (arrow A; see Figure 3(a)), and preventing the fluid recirculation device 1 from coming off toward the other end. As a result, the first locking portion 20 prevents the fluid recirculation device 1 from entering the abdominal cavity 3. On the other hand, if an external force is applied to displace the fluid return device 1 toward one end, the second locking portion 30 catches on the outer surface of the wall 2a of the abdominal organ 2, resisting the force in the direction of displacement (arrow B; see Figure 3(a)), and preventing the fluid return device 1 from coming off toward one end. As a result, the second locking portion 30 prevents the fluid return device 1 from protruding into the abdominal organ 2.

[0048] In this manner, the body fluid recirculation device 1 can be placed in the patient's body with the first end 10a positioned within the abdominal organs 2 and the second end 10b positioned in the abdominal cavity 3. When the pressure inside the abdominal organs 2 becomes lower than the internal pressure of the abdominal cavity 3, which is expanded with body fluids, body fluids flow into the main body 10 from the opening 15 at the second end 10b of the main body 10 and the inflow assist part 14. The body fluids that flow into the main body 10 flow toward one end of the main body 10 and are discharged into the abdominal organs 2 from the outlet 13c of the valve part 13. Since the valve part 13 is a backflow prevention valve, backflow of body fluids, including digestive fluids, from the abdominal organs 2 to the abdominal cavity 3 is suppressed.

[0049] The effects of the body fluid recirculation device 1 of this embodiment will be described below. The cylindrical body portion 10 of the fluid recirculation device 1 has a first end portion 10a located at one end in the axial direction Ax, which is disposed within the abdominal organs 2, and a second end portion 10b located at the other end, which is disposed within the abdominal cavity 3. The first end portion 10a is provided with a valve portion 13 having a fluid outlet 13c on the downstream side in the direction of fluid flow. The fluid recirculation device 1 returns fluid from the abdominal cavity 3, which flows in from the second end portion 10b, to the abdominal organs 2 by draining it out through the outlet 13c of the valve portion 13. The fluid recirculation device 1 causes fluid accumulated in the peritoneal cavity 3 to flow into the abdominal organs 2. As a result, the fluid in the peritoneal cavity 3 is recirculated after being absorbed into the body through the digestive action of the abdominal organs 2. Therefore, compared to directly recirculating the fluid from the peritoneal cavity 3 into the blood vessels, the risk of developing serious complications such as heart failure and thrombus formation can be significantly reduced with the fluid recirculation device 1. Moreover, because the fluid from the peritoneal cavity 3 is not directly recirculated into the blood vessels, treatment using the fluid recirculation device 1 can be expected even in cases that are not suitable for conventional peritoneal venous shunt surgery. Furthermore, because the fluid recirculation device 1 directly connects the abdominal cavity 3 and the abdominal organs 2, the axial length of the device is shorter compared to conventional peritoneal venous shunt surgery, reducing the burden on the patient's body during and after the procedure. Therefore, the fluid recirculation device 1 makes it possible to recirculate the fluids of the abdominal cavity 3 into the body more effectively and with less invasiveness than conventional methods.

[0050] Furthermore, the fluid recirculation device 1 is further equipped with positioning parts (for example, a first locking part 20 and a second locking part 30) that position the outlet 13c so that it is located within the abdominal organs 2. By positioning the outlet 13c of the fluid recirculation device 1 within the abdominal organs 2 using the positioning parts, axial displacement of the fluid recirculation device 1 and deviation of the fluid recirculation device 1 into the abdominal cavity 3 or abdominal organs 2 can be suppressed.

[0051] Furthermore, in the main body portion 10 of the body fluid recirculation device 1, at least the portion that passes through the wall 2a of the abdominal organ 2 to the valve portion 13 is formed in a tubular shape by a membrane (e.g., a cap portion 12) that is resistant to digestive fluids in the abdominal organ 2. This prevents the main body portion 10 from being damaged by digestive fluids in the abdominal organ 2, and prevents leakage of body fluids containing digestive fluids into the abdominal cavity 3.

[0052] Furthermore, the second end 10b of the main body 10 has an inflow assisting part 14 that assists in the inflow of body fluid into the main body 10. As a result, body fluid flows into the main body 10 not only through the opening 15 of the second end 10b but also through the inflow assisting part 14, making it possible to efficiently guide body fluid from the abdominal cavity 3 into the abdominal organs 2 via the body fluid return device 1.

[0053] The present invention is not limited to the embodiments described above, and various improvements and design changes may be made without departing from the spirit of the invention. Note that, apart from the details described below, the configuration is the same as that of the embodiments described above, and a detailed explanation will be omitted.

[0054] <Example 1> The shape of the second locking portion 30 illustrated in the above embodiment is merely an example and is not limited thereto; it can be changed as appropriate. For example, as shown in Figure 5, in the modified example 1 of the body fluid recirculation device 1A, the second locking portion 30A has a shape similar to the first locking portion 20, in which the metal skeleton expands and protrudes outward from the other end towards the one end.

[0055] Furthermore, the axial length of the main body 10 can be arbitrarily changed as appropriate, for example, depending on the implantation site. In the fluid recirculation device 1A of the modified example 1, the axial length of the main body 10 is shorter than that of the fluid recirculation device 1 of the embodiment.

[0056] <Modification 2> In the above embodiment, a configuration in which the skeletal portion 21 of the first locking portion 20 is not covered by a cover was illustrated, but this is just one example and is not limited to this. That is, as shown in Figure 6, in the modified example 2 of the fluid recirculation device 1B, the skeletal portion 21 of the first locking portion 20 is also covered by a cover 22, similar to the second locking portions 30, 30A, and 30B. As a result, the tip of the skeletal portion 21 of the first locking portion 20 is less likely to bite into the wall 2a of the abdominal organ 2, making it easier to remove the fluid recirculation device 1B that has been placed in the abdominal organ 2.

[0057] Furthermore, in the fluid recirculation device 1B of Modified Example 2, the second locking portion 30B has a shape similar to the first locking portion 20, in which the metal skeleton expands and protrudes outward from one end to the other. With this shape, when the fluid recirculation device 1B implanted in the abdominal organ 2 is pulled out from the abdominal organ 2 side, the second locking portion 30B becomes less of a resistance compared to the second locking portion 30A of Modified Example 1, making removal easier.

[0058] <Variation 3> In the above embodiment, an example was described in which an inflow assist portion 14 is formed in the body fluid recirculation device 1 by providing a plurality of through holes 14a in the coating portion 12. However, the configuration of the inflow assist portion 14 is not limited to the above. For example, as shown in Figure 7, in the modified body fluid recirculation device 1C of Modified Example 3, the inflow assist portion 14 may be configured by covering the periphery of the skeletal portion 11 with a mesh-like porous membrane 16 on the second end 10b side of the main body portion 10. The same effects as in the above embodiment can be obtained with the body fluid recirculation device 1C of Modified Example 3.

[0059] Furthermore, although both the first locking portion 20 and the second locking portions 30, 30A, and 30B are provided as positioning portions, it is sufficient to provide at least the first locking portion 20 in order to prevent the fluid return devices 1, 1A, 1B, and 1C from falling into the abdominal cavity 3. Similarly, it is sufficient to provide at least the second locking portions 30, 30A, and 30B in order to prevent the fluid return devices 1, 1A, 1B, and 1C from falling into the abdominal organs 2.

[0060] <Modification 4> The following description of the body fluid recirculation device 1D according to Modification 4 of this embodiment will be given with reference to Figures 8 and 9. Figure 8 is a partial perspective view showing one end of the body fluid recirculation device 1D of Modification 4. Figure 9 is a cross-sectional view taken along line IX-IX in Figure 8.

[0061] The fluid recirculation device 1D shown in Figures 8 and 9 is equipped with a first valve portion 17 and a second valve portion 18 at one end that is disposed within the abdominal organs 2. In Figure 9, the configuration of the fluid recirculation device 1D other than the first valve portion 17 and the second valve portion 18 is the same as that of the fluid recirculation device 1B shown in Figure 6, but these configurations can be changed as appropriate in the modified example 4.

[0062] The first valve section 17 is a backflow prevention valve connected to one end of the main body section 10, and is responsible for preventing the backflow of bodily fluids from one end to the other. The first valve section 17 is formed integrally with the main body section 10 and is formed in a tapered shape in which the cross-sectional area of ​​the flow path at one end is smaller than the cross-sectional area of ​​the flow path at the other end. The first valve section 17 has a tapered section 17a and a flat section 17b extending from the other end to the one end. An outlet 17c is formed at one end of the flat section 17b. The configuration and operation of the first valve section 17 are the same as those of the valve section 13 described above, so a redundant explanation will be omitted.

[0063] The first valve portion 17 is formed from a biocompatible and elastically deformable thin film material. Examples of materials for the first valve portion 17 include silicon, fluororesins such as PTFE, and polyethylene resins such as ultra-high molecular weight polyethylene. Since the first valve portion 17 does not come into direct contact with the digestive fluid due to the second valve portion 18, the first valve portion 17 can be made from a material with properties suitable for a backflow prevention valve, such as silicon, regardless of acid resistance.

[0064] When the first valve portion 17 is formed from silicone, it can be formed on one end of the main body portion 10 by dipping. Furthermore, when the first valve portion 17 is formed from fluororesin or polyethylene resin, it can be formed using the same method as the valve portion 13 described above.

[0065] The second valve portion 18 is a backflow prevention valve attached to the main body portion 10 at one end of the main body portion 10. The second valve portion 18 is attached to the outside of the first valve portion 17 and covers the first valve portion 17 from the outside. The second valve portion 18 prevents backflow of bodily fluids from one end to the other and also prevents the first valve portion 17 from being exposed to digestive fluids in the abdominal organs 2 and deteriorating.

[0066] The second valve section 18, like the first valve section 17, is formed in a tapered shape where the flow path cross-sectional area at one end is smaller than the flow path cross-sectional area at the other end. The second valve section 18 has a tapered section 18a and a flat section 18b extending from the other end to the one end. An outlet 18c is formed at one end of the flat section 18b. The configuration and operation of the second valve section 18 are the same as those of the valve section 13 described above, so a redundant explanation will be omitted.

[0067] The second valve portion 18 is integrated by covering and fixing a thin-film cylindrical body, with a valve formed at one end, to one end of the main body portion 10 having the first valve portion 17. The other end 18d of the second valve portion 18 is liquid-tightly fixed to the outer circumference of the main body portion 10 by, for example, welding or adhesive. This prevents digestive fluids from the abdominal organs 2 from entering between the other end 18d and the main body portion 10. The second valve portion 18 may or may not have a skeletal structure.

[0068] The second valve portion 18 is formed from a biocompatible and elastically deformable thin film material. Examples of materials for the second valve portion 18 include silicon, fluororesins such as PTFE, and polyethylene resins such as ultra-high molecular weight polyethylene. The second valve portion 18 may be formed from the same material as the first valve portion 17, or from a different material. Furthermore, if the second valve portion 18 is formed from a fluororesin or polyethylene resin, which has higher acid resistance than silicon, the acid resistance of the second valve portion 18, which is exposed to digestive fluids of the abdominal organs 2, can be improved. Alternatively, both the first valve portion 17 and the second valve portion 18 may be formed from silicon.

[0069] The main body 10 of the body fluid recirculation device 1D may also be equipped with a backflow prevention valve (not shown) at the other end, in addition to the first valve portion 17 and the second valve portion 18. Furthermore, the first valve portion 17 and the second valve portion 18 do not have to be arranged to partially overlap in the axial direction, and may be arranged to be spaced apart in the axial direction. Furthermore, both valve portions do not necessarily have to be located on one end of the main body 10; one valve portion may be located inside the abdominal organs, and the other valve portion may be located inside the main body, outside the abdominal organs in the axial direction (not shown). In this case, the valve portion located inside the abdominal organs is preferably made of a highly acid-resistant material.

[0070] As described above, the body fluid recirculation device 1D has a first valve portion 17 connected to the main body portion 10 and a second valve portion 18 covering the first valve portion 17 from the outside, with the valve portion located at one end. With the fluid recirculation device 1D, even if one of the first valve portion 17 and the second valve portion 18 is damaged by rupture or other reasons, the other of the first valve portion 17 and the second valve portion 18 functions as a backflow prevention valve, suppressing the backflow of digestive fluid from the abdominal organs 2 to the other end of the fluid recirculation device 1D. Therefore, with the fluid recirculation device 1D, the leakage of body fluids, including digestive fluid, into the abdominal cavity 3 can be suppressed more reliably than with a configuration that does not have multiple valve portions. Furthermore, in the fluid recirculation device 1D, at one end that is positioned within the abdominal organ 2, the second valve portion 18 covers the first valve portion 17 from the outside. Therefore, the outer second valve portion 18 is exposed to the digestive fluid of the abdominal organ 2, but the inner first valve portion 17 does not come into direct contact with the digestive fluid of the abdominal organ 2. As a result, deterioration of the first valve portion 17 by acidic digestive fluid can be suppressed, and the anti-reflux function of the first valve portion 17 can be easily maintained for a long period of time.

[0071] Furthermore, the body fluid recirculation device 1D can, for example, use a material with properties suitable for a backflow prevention valve regardless of acid resistance for the inner first valve portion 17, and use a material with higher acid resistance than the first valve portion 17 for the outer second valve portion 18. This makes it possible to ensure acid resistance and improve the backflow prevention function of the body fluid recirculation device 1D as a whole.

[0072] <Other> Furthermore, in the above embodiments and modifications 1 to 4, the coating portion 12 is formed from an acid-resistant material, but this is just one example and not limited to this. For example, in cases where the pH value is high depending on the type and condition of the abdominal organ 2 to be implanted, or when the implantation period is relatively short, the coating portion 12 does not necessarily need to be acid-resistant. Furthermore, in the above embodiments and modifications 1 to 4, the coating portion 12 is exemplified as being attached to the outer circumference of the skeletal portion 11, but this is merely an example and is not limited to this; for example, it may be attached to the inner circumference of the skeletal portion 11.

[0073] Furthermore, while examples of fluid return devices 1, 1A, 1B, 1C, and 1D equipped with an inflow assist section 14 have been provided, this is merely an example and not limited to these. For example, when the device is placed in the abdominal cavity 3, where there is a relatively large amount of body fluid, sufficient body fluid can flow into the main body 10 from the second end 10b, so it is not always necessary to include an inflow assist section 14.

[0074] Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0075] 1, 1A, 1B, 1C, 1D…Body fluid recirculation device, 2…Abdominal organs, 2a…Wall, 2b…Opening, 3…Abdominal cavity, 10…Main body, 10a…First end, 10b…Second end, 11…Skeleton, 11a…Extension, 12…Coating, 13…Valve, 13a…Tapered section, 13b…Flat section, 13c…Outlet, 14…Inflow assist section, 14a…Through hole, 15…Opening, 16…Porous membrane, 17…First valve, 18…Second valve, 20…First locking section (positioning section), 21…Skeleton, 22…Cover, 30, 30A, 30B…Second locking section (positioning section), 31…Skeleton, 32…Cover

Claims

1. A fluid recirculation device having a cylindrical main body, The main body is, The first end, located at one end in the axial direction, is positioned within the abdominal organs, while the second end, located at the other end, is positioned within the abdominal cavity. The first end is provided with a valve portion having an outlet for body fluid on the downstream side in the direction of body fluid flow. The valve portion comprises a first valve portion connected to the main body portion and a second valve portion covering the first valve portion from the outside. A fluid return device that causes the fluid from the abdominal cavity, which flows in from the second end, to flow out from the outlet of the valve and return to the abdominal organs.

2. The system further includes a positioning unit that positions the outlet so that it is located within the abdominal organs. The fluid recirculation device according to claim 1.

3. In the main body, at least from the portion passing through the wall of the abdominal organ to the valve portion, it is formed in a tubular shape by a membrane that is resistant to the digestive fluids within the abdominal organ. A body fluid recirculation device according to claim 1 or claim 2.

4. The second end has an inflow assist portion that assists in the inflow of the bodily fluid into the main body. A body fluid recirculation device according to any one of claims 1 to 3.

5. The second valve portion is formed of a material with higher acid resistance than the first valve portion. A body fluid recirculation device according to any one of claims 1 to 4.

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