Patent Application
20240423628
The present invention relates to a medical device that is used for a blood vessel or an in-vivo lumen of a digestive organ or the like.
In treatment of an in-vivo lumen, a device having a basket is used in some cases. Specific examples include: a treatment in which an abnormal object such as a thrombus generated in a blood vessel or a calculus generated in a digestive organ tract such as a bile duct is trapped inside a basket and removed; and embolization in which a basket is indwelled in a vascular lesion portion such as an aneurysm to alter the blood flow to prevent rupture of the bulge. Further, embolization in which a basket is disposed in a bulge and a coil is packed in this basket to fill the bulge, thereby preventing rupture of the bulge, is also known.
For example, Patent Literature 1 describes an embolic protection device for use in a lumen. The embolic protection device includes: a core wire; and a cannula attached to the core wire and extending in the proximal direction about the core wire. The cannula forms a basket portion including a plurality of struts and a filter portion. The filter portion has a plurality of openings formed in the cannula. The basket portion is movable between an expanded state and a collapsed state. Patent Literature 2 describes a catheter device that has: a catheter to be inserted into a lumen of a human body; a branch portion connected to a base end portion of the catheter and provided with an insertion hole for allowing passage therethrough of a guide wire to be used when the catheter is inserted into a lumen of the human body; and a liquid introducing means that introduces a liquid such as a drug solution into the catheter through a tube connected to the branch portion. At the leading end of the catheter, an embolus trapping means for trapping an embolus in a lumen of the human body is disposed. The embolus trapping means is formed by a net member that opens and closes in a parachute shape with the interval between both ends thereof being reduced or increased. Patent Literature 3 describes a device that includes a self-expandable-type resilient permeable shell. The self-expandable-type resilient permeable shell includes a plurality of elongated resilient filaments with a woven structure fixed to each other at proximal ends and distal ends of the filaments. Further, the self-expandable-type resilient permeable shell has: a radially constrained elongated state configured for delivery within a microcatheter, with the thin woven filaments extending longitudinally from the proximal end to the distal end radially adjacent to each other along the lengths of the filaments; and an expanded relaxed state with a globular longitudinally shortened configuration relative to the radially constrained state, with the woven filaments forming the self-expandable-type resilient permeable shell in a smooth path radially expanded from the longitudinal axis between the proximal end and the distal end including a plurality of openings in the shell formed between the woven filaments. The largest of the openings is configured to allow blood flow through the openings at a velocity below a thrombotic threshold velocity. Patent Literature 4 describes an embolus trapping device that includes: a long shaft member whose leading end side is sent into a lumen; a leading end guide portion that is flexible and disposed at the leading end of the shaft member; and an embolus trapping filter having a filter portion provided on the base end side of the leading end guide portion and composed of a mesh formed by wires having elasticity or shape memory properties, the filter portion having a basket shape that contracts in a catheter for device transport and expands when released from the catheter into a lumen, and a bundling portion at which the wires forming the filter portion are bundled at each of the leading end side and the base end side. The embolus trapping device is disposed such that the opening of the filter portion is oriented toward the leading end side of the shaft member and opposed to the blood flow, thereby trapping an embolus released in the lumen. Patent Literature 5 describes an occlusion device including: a substantially tubular structure that has a proximal end region and a distal end region, that has a first expanded state and a second collapsed state, that has, in the second collapsed state, dimensions suitable for insertion through the vascular system of a patient into the neck of an aneurysm, that has an outer surface capable of coming into contact with the aneurysm in the expanded state, and that further has an inner surface; and a control ring disposed in the proximal end region of the structure and having a substantially annular body at least substantially surrounding the proximal end region in order to prevent expansion in the radial direction of the proximal end region and to provide an engagement feature during operation of the occlusion device. Patent Literature 6 describes a system including: a braided tubular implant having a distal implant end portion and a proximal implant end portion, and being invertible about the distal implant end portion; and a tubular delivery member around the braided tubular implant, the tubular delivery member having a distal end portion releasably connected to the distal implant end portion, wherein translation of the braided tubular implant distally from the tubular member causes the braided tubular implant to be inverted and collapsed into itself, thereby forming an occlusive sack configured to occlude an aneurysm.
In the devices as in Patent Literatures 1 to 5, a bundling portion at which wires forming a basket are bundled is present at a distal end portion of the basket. Thus, there has been a problem that this bundling portion may come into contact with the tube wall of an in-vivo lumen, thereby damaging the tube wall.
In the system as in Patent Literature 6, the distal end portion of the braided tubular implant is invertible about the longitudinal axis and is collapsed inside the braided tubular implant. Therefore, there has been a problem that the configuration of such a system becomes complicated, and the diameter of the microcatheter in which the braided tubular implant is disposed during delivery becomes large. Thus, there has been room for improvement in order to realize further minimal invasiveness. The system as in Patent Literature 6 also has a problem that, since the diameter of the microcatheter is large, it is difficult to perform treatment of a peripheral artery.
The present invention has been made in view of the circumstances described above. An object of the present invention is to provide a medical device that is less likely to damage, in an in-vivo lumen, a tube wall or the like of a living body, that is minimally invasive, and with which treatment of a peripheral artery is easily performed.
A medical device that has solved the above problems is as follows.
[1] A medical device comprising:
[2] The medical device according to [1], wherein
[3] The medical device according to [1] or [2], wherein
[4] The medical device according to [3], wherein
[5] The medical device according to any one of [1] to [4], wherein
[6] The medical device according to any one of [1] to [5], wherein
[7] The medical device according to [6], wherein
[8] The medical device according to any one of [1] to [7], wherein
[9] The medical device according to [8], wherein
[10] The medical device according to any one of [1] to [9], wherein
[11] The medical device according to any one of [1] to [10], comprising a connection member on the proximal side with respect to the basket and on the distal side with respect to the basket pusher.
[12] The medical device according to any one of [1] to [11], wherein
[13] The medical device according to any one of [1] to [12], wherein
[14] The medical device according to any one of [1] to [13], wherein
According to the medical device of the present invention, in the state where the basket is accommodated in the outer tube, the first bundling portion has the first end being an end portion on a far side with respect to the second bundling portion and the second end being an end portion on a near side with respect to the second bundling portion, and in the state where the entirety of the basket has come out of the outer tube and no external force is applied to the basket, the second end is positioned on the distal side with respect to the first end. Therefore, with respect to the first bundling portion present at a distal portion of the basket, in the state where the basket is accommodated in the outer tube, the first end is positioned on the distal side with respect to the second end, and in the state where the entirety of the basket has come out of the outer tube and no external force is applied to the basket, the second end is positioned on the distal side with respect to the first end. Since the second end is positioned on the distal side with respect to the first end when the entirety of the basket has come out of the outer tube and no external force is applied to the basket, a state where the distal end portion of the basket is bent is established. Accordingly, the first bundling portion of the basket is less likely to come into contact with the tube wall of the in-vivo lumen, and the tube wall can be less likely to be damaged by the first bundling portion. Further, in the state where the basket is accommodated in the outer tube, the first end is positioned on the distal side with respect to the second end. Therefore, in the outer tube, the positions of the wires forming the basket and the first bundling portion do not overlap with each other. Therefore, the diameter of the basket portion is less likely to be large, and an outer tube having a smaller diameter can be used. In addition, the force applied from the hand side to push the basket to the distal side is easily transmitted, and thus, the basket is easily released from the outer tube. As a result, a medical device that is minimally invasive can be realized.
Hereinafter, the present invention is specifically described below based on the following embodiments; however, the present invention is not restricted by the embodiments described below of course, and can be certainly put into practice after appropriate modifications within in a range meeting the gist of the above and the below, all of which are included in the technical scope of the present invention. In the drawings, hatching or a reference sign for a member may be omitted for convenience, and in such a case, the description and other drawings should be referred to. In addition, sizes of various members in the drawings may differ from the actual sizes thereof, since priority is given to understanding the features of the present invention.
As shown in
The medical device 1 can be used in: a treatment in which an abnormal object present in an in-vivo lumen such as a thrombus generated in a blood vessel or a calculus generated in a digestive organ tract such as a bile duct is trapped inside the basket 30 and removed from the in-vivo lumen; embolization in which the basket 30 is indwelled in a vascular lesion portion such as an aneurysm to promote thrombosis to prevent rupture of the bulge; and the like. The medical device 1 introduces the outer tube 10 into an in-vivo lumen and causes the basket 30 to be indwelled in a target site from the outer tube 10. In embolization, for example, the basket 30 is disposed in a bulge in a terminal portion of an in-vivo lumen, a bulge in a side wall portion of an in-vivo lumen, a main tube peripheral portion of an in-vivo lumen, or the like. Then, a medical long object is indwelled inside the basket 30 disposed in the bulge, the main tube peripheral portion, or the like to promote thrombosis of the bulge. Examples of the medical long object include a coil, a wire, and a string-like object. Further, the medical long object may be a tube for transporting a long object such as a coil. In addition, the tubular medical long object may be for transporting a semi-solid fluid, a gel-like material, a semi-solid, a liquid, or the like, or further, a bag-like object, into a bulge. The liquid for the tubular medical long object may be a liquid that hardens or a liquid that is deposited, for example.
As shown in
The outer tube 10 is a tubular member extending in the longitudinal direction and has at least one lumen extending in the longitudinal direction. The number of the lumens of the outer tube 10 may be plural, but is preferably one. When the number of the lumens of the outer tube 10 is one, the outer diameter of the outer tube 10 can be reduced. As a result, the minimal invasiveness of the medical device 1 can be improved.
The material forming the outer tube 10 is preferably a resin or a metal. Examples of the resin forming the outer tube 10 include polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, fluorine-based resins, vinyl chloride-based resins, silicone-based resins, natural rubber, etc. Only one of these materials may be used, or two or more of these materials may be used in combination. Among them, the resin forming the outer tube 10 is preferably at least one of polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, and fluorine-based resins. When the material forming the outer tube 10 is at least one of polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, and fluorine-based resins, the slipperiness of the surface of the outer tube 10 can be enhanced, and the insertability of the outer tube 10 into a lumen such as a blood vessel can be improved. A tube, to serve as the outer tube 10, that is formed from the resin can be produced by using a normal method such as extrusion molding and injection molding.
Examples of the metal forming the outer tube 10 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, gold, Ni—Ti alloys, Co—Cr alloys, and combinations thereof. As a tube, to serve as the outer tube 10, that is formed from the metal, a tube obtained by spirally winding a metal wire material, a tube obtained by braiding metal wire materials, or the like may be used. In addition, the outer tube 10 may be a tube obtained by combining a metal and a resin. A tubular body formed from a resin and having a reinforcing material such as a metal wire material provided therein may be used as the outer tube 10. In the case where a tube-like member made of a resin and having a wire material provided therein is used as the outer tube 10, the wire material is preferably formed from a Ni—Ti alloy since the wire material has excellent shape memory properties and high elasticity. The wire material may be a fiber material of the above-described metal, a polyarylate fiber, an aramid fiber, an ultra-high molecular weight polyethylene fiber, a PBO fiber, a carbon fiber, or the like. The fiber material may be a monofilament or may be a multifilament.
The outer tube 10 may be composed of a single layer or may be composed of a plurality of layers. In addition, in the longitudinal direction, a part of the outer tube 10 may be composed of a single layer, and the other part of the outer tube 10 may be composed of a plurality of layers.
With respect to the outer tube 10, the outer surface of the outer tube 10 is preferably coated with a hydrophilic resin. That is, the outer tube 10 preferably has a hydrophilic resin layer outside the outer tube 10. When the outer surface of the outer tube 10 is coated with a hydrophilic resin, the slipperiness of the outer tube 10 can be enhanced, and insertability in an in-vivo lumen can be enhanced.
With respect to the outer tube 10, the inner surface of the outer tube 10 is preferably coated with a fluorine-based resin. In other words, the outer tube 10 preferably has a fluorine-based resin layer inside the outer tube 10. When the outer tube 10 has a fluorine-based resin layer inside the outer tube 10, the slipperiness of the inner surface the outer tube 10 is improved. Therefore, in the inner cavity of the outer tube 10, the basket 30 is easily moved in the longitudinal direction.
The cross-sectional shape of the outer shape of the outer tube 10 in a cross-section perpendicular to the longitudinal direction may be a circular shape, an elliptical shape, a polygonal shape, or a combination thereof. In addition, the cross-sectional shape of the inner cavity of the outer tube 10 in a cross-section perpendicular to the longitudinal direction may also be a circular shape, an elliptical shape, a polygonal shape, or a combination thereof.
As shown in
The material forming each wire 20 preferably has elasticity, and examples thereof include metal wire materials that are single wires, flat wires, multi-wires, composite material wires, or twisted wires formed from stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, Ni—Ti alloys, Co—Cr alloys, etc. Among them, the material forming each wire 20 is preferably a material having superelasticity, and more preferably a metal wire material of a Ni—Ti alloy. When the material forming each wire 20 is a metal wire material of a Ni—Ti alloy, the elasticity of each wire 20 can be enhanced, and even if the deformation amount of the basket 30 released from the outer tube 10 is large, the return amount is large, and thus, the basket 30 can be less likely to lose its shape.
It is sufficient that the number of the wires 20 of the basket 30 is plural, and the number of the wires 20 can be selected according to the inner diameter of an in-vivo lumen or the like. In the drawings, the number of the wires 20 of the basket 30 is limited. However, in the embodiment of the present invention, the basket 30 can be, for example, a basket 30 including 8 or more and 64 or less wires 20. The diameter of each element wire of each wire 20 can be set according to the size of the basket 30, the number and the material of the wires 20, and the like. The number of the wires 20 of the basket 30 is preferably 16 or more and 32 or less.
Preferably, the basket 30 is deformable and is slidable inside a tube having an inner diameter of 0.021 inches (0.5334 mm) or less, and more preferably slidable inside a tube having an inner diameter of 0.017 inches (0.4318 mm) or less. In the case where the number of the lumens of the outer tube 10 is one, preferably, the inner diameter of the outer tube 10 is 0.017 inches or less, and the basket 30 is disposed in the inner cavity of this outer tube 10. In the case where the outer tube 10 has a plurality of lumens, the inner diameter of the lumen in which the basket 30 is disposed is preferably 0.017 inches or less. When the basket 30 is deformable and is slidable inside a tube having an inner diameter of 0.017 inches or less, the outer diameter of the outer tube 10 can be reduced. Accordingly, the medical device 1 that has good insertability and that is minimally invasive can be realized.
As shown in
The material forming the basket pusher 40 is preferably a metal, and examples thereof include metals such as stainless steel, carbon steel, and nickel-titanium alloys. Among them, the material forming the basket pusher 40 is preferably stainless steel. When the material forming the basket pusher 40 is stainless steel, the rigidity of the basket pusher 40 can be enhanced. As a result, the force applied to the basket pusher 40 can be efficiently transmitted to the basket 30, and thus, it becomes easier to perform the operation of releasing the basket 30 from the outer tube 10.
As shown in
Examples of a method for bundling and fixing the plurality of wires 20 at the first bundling portion 51 and the second bundling portion 52 include welding the plurality of wires 20, crimping the plurality of wires 20 together using a separate member, adhering the plurality of wires 20 using an adhesive, and fixing the plurality of wires 20 with a brazing material, and a combination thereof. Among them, crimping and fixing the plurality of wires 20 by the separate member at the first bundling portion 51 and the second bundling portion 52 is preferable. When the plurality of wires 20 are crimped and fixed by the separate member at the first bundling portion 51 and the second bundling portion 52, the plurality of wires 20 are easily and firmly fixed at the first bundling portion 51 and the second bundling portion 52, and the basket 30 is less likely to be broken.
Examples of the separate member that bundles and fixes the plurality of wires 20 at the first bundling portion 51 and the second bundling portion 52 include a ring-shaped member, a member having a C-shaped cross-section obtained by making a cut in a ring, a coil-shaped member obtained by winding a wire material, and a member that binds and fixes the plurality of wires 20 with a string-like object. Among them, the separate member that bundles and fixes the plurality of wires 20 is preferably a ring-shaped member, and more preferably a ring-shaped swaged member. When the separate member that bundles and fixes the plurality of wires 20 is a ring-shaped swaged member, the plurality of wires 20 can be firmly fixed, and the plurality of wires 20 can be less likely to be de-bundled.
As the material forming the separate member that bundles and fixes the plurality of wires 20, the same materials as those for the wires 20 of the basket 30 and the basket pusher 40 can be used, for example. Among them, the material forming the separate member that bundles and fixes the plurality of wires 20 is preferably stainless steel. When the material forming the separate member that bundles and fixes the plurality of wires 20 is stainless steel, the fixing strength of the plurality of wires 20 can be enhanced, and the durability of the separate member that bundles and fixes the plurality of wires 20 can be improved. Further, the material forming the separate member that bundles and fixes the plurality of wires 20 is more preferably a radiopaque material. Examples of the radiopaque material include platinum, gold, tungsten, iridium, palladium, tantalum, and an alloy in which at least one of these is combined. When the material forming the separate member that bundles and fixes the plurality of wires 20 is the radiopaque material, the positions of the first bundling portion 51 and the second bundling portion 52 can be confirmed under X-ray fluoroscopy. Thus, it is possible to grasp the position of the basket 30 in a body.
As shown in
Preferably, in the state where the basket 30 is accommodated in the outer tube 10, the wires 20 are present on the proximal side with respect to the second end 62 and the wires 20 are not present on the distal side with respect to the first end 61. In the state where the basket 30 is accommodated in the outer tube 10, when the wires 20 are not present on the distal side with respect to the first end 61, the wires 20 are not present at a distal end 30d of the basket 30. As a result, when the distal end 30d of the basket 30 comes into contact with another object such as a tube wall of an in-vivo lumen, the other object can be prevented from being damaged by the wires 20, and the medical device 1 that is minimally invasive can be realized. In addition, in the state where the basket 30 is accommodated in the outer tube 10, when the wires 20 are present on the proximal side with respect to the second end 62, the wires 20 of the basket 30 can be sufficiently bundled and fixed at the first bundling portion 51, and thus, the fixing strength of the wires 20 can be enhanced. In addition, preferably, rounding of the corner portion of the first end 61, i.e., so-called R-processing, has been performed on the first end 61. When the R-processing has been performed on the corner portion of the first end 61, even if the first end 61 comes into contact with another object such as a tube wall of an in-vivo lumen, the other object can be less likely to be damaged by the first end 61.
As shown in
At the first bundling portion 51 present at a distal portion of the basket 30, in the state where the entirety of the basket 30 has come out of the outer tube 10 and no external force is applied to the basket 30, the second end 62 is positioned on the distal side with respect to the first end 61, and thus, a state where the distal end portion of the basket 30 is bent toward the proximal side is established. As a result, the first bundling portion 51 of the basket 30 is less likely to come into contact with the tube wall of the in-vivo lumen, and thus, the tube wall can be less likely to be damaged by the first bundling portion 51. Thus, the medical device 1 that is minimally invasive can be realized.
At the first bundling portion 51 present at the distal portion of the basket 30, in the state where the basket 30 is accommodated in the outer tube 10, the first end 61 is positioned on the distal side with respect to the second end 62, and therefore, in the outer tube 10, the positions of the wires 20 forming the basket 30 and the first bundling portion 51 do not overlap with each other. Therefore, the outer diameter of the basket 30 is less likely to be large, and thus, it is not necessary to make the inner cavity of the outer tube 10 accommodating the contracted basket 30 larger than that of conventional art. Accordingly, the outer tube 10 having a diameter smaller than that of conventional art can be used. As a result, the medical device 1 that is minimally invasive can be realized. Further, in the outer tube 10, a state where the distal end portion of the basket 30 is bent toward the proximal side is not established. Therefore, the force applied from the hand side to push the basket 30 to the distal side in order to release the basket 30 from the outer tube 10 is easily transmitted to the basket 30, and thus, the basket 30 can be easily and smoothly released from the outer tube 10.
Preferably, as shown in
Preferably, as shown in
Preferably, as shown in
Preferably, the plurality of wires 20 of the basket 30 include a first wire group 21 and a second wire group 22, and the length of the wire 20 of the first wire group 21 is shorter than the length of the wire 20 of the second wire group 22. The length of each wire 20 is the length from the distal end 20d to a proximal end 20p of a single wire 20. When the length of the wire 20 of the first wire group 21 is shorter than the length of the wire 20 of the second wire group 22, if the state where the entirety of the basket 30 has come out of the outer tube 10 and no external force is applied to the basket 30 is established, the part where the first wire group 21 of the basket 30 is present is easily positioned inside the bending of the basket 30. Therefore, when the entirety of the basket 30 is exposed from the outer tube 10 to allow the distal end portion of the basket 30 to bend toward the proximal side, the start point or the position of the bending is easily controlled. As a result, the effect of causing the distal end portion of the basket 30 to be less likely to come into contact with another object can be further enhanced. The number of the wires 20 of the first wire group 21 may be one or may be plural. The number of the wires 20 of the second wire group 22 may be one or may be plural as well.
The length of the wire 20 of the first wire group 21 is preferably less than 100%, more preferably 99.5% or less, and further preferably 99% or less of the length of the wire 20 of the second wire group 22. When the upper limit value of the ratio between the length of the wire 20 of the first wire group 21 and the length of the wire 20 of the second wire group 22 is set to be in the above range, if the state where the entirety of the basket 30 has come out of the outer tube 10 and no external force is applied to the basket 30 is established, the first wire group 21 is easily positioned inside the bending of the basket 30, and thus, the bending of the basket 30 is easily controlled. The lower limit value of the ratio between the length of the wire 20 of the first wire group 21 and the length of the wire 20 of the second wire group 22 is not limited in particular, and can be 90% or more, 93% or more, or 95% or more, for example.
In a cross-section perpendicular to the extending direction of the basket pusher 40, the distance D2 between the first wire group 21 and the second wire group 22 is preferably 1.1 times or more, more preferably 1.2 times or more, and further preferably 1.3 times or more the distance D3 between the first wire group 21 and the third wire group 23. When the lower limit value of the ratio between the distance D2 between the first wire group 21 and the second wire group 22 and the distance D3 between the first wire group 21 and the third wire group 23 is set to be in the above range, the distance D2 between the first wire group 21 and the second wire group 22 can be made sufficiently large as compared with the distance D3 between the first wire group 21 and the third wire group 23. Accordingly, in the basket 30, the first wire group 21 easily serves as the start point of the bending. In a cross-section perpendicular to the extending direction of the basket pusher 40, the distance D2 between the first wire group 21 and the second wire group 22 is preferably 5 times or less, more preferably 4 times or less, and further preferably 3 times or less the distance D3 between the first wire group 21 and the third wire group 23. When the upper limit value of the ratio between the distance D2 between the first wire group 21 and the second wire group 22 and the distance D3 between the first wire group 21 the third wire group 23 is set to be in the above range, the basket 30 is less likely to be excessively large. As a result, the outer diameter of the outer tube 10 can also be prevented from becoming excessively large.
In the state where the entirety of the basket 30 has come out of the outer tube 10 and no external force is applied to the basket 30, the radius r21 of the bent portion of the wire 20 of the first wire group 21 on the distal side with respect to the second end 62 of the first bundling portion 51 is preferably 0.9 times or less, more preferably 0.8 times or less, and further preferably 0.7 times or less the radius r22 of the bent portion of the wire 20 of the second wire group 22 on the distal side with respect to the second end 62 of the first bundling portion 51. When the upper limit value of the ratio between the radius r21 of the bent portion of the wire 20 of the first wire group 21 on the distal side with respect to the second end 62 of the first bundling portion 51 and the radius r22 of the bent portion of the wire 20 of the second wire group 22 is set to be in the above range, the degree of the bending of the wire 20 of the first wire group 21 can be made sufficiently larger than the degree of the bending of the wire 20 of the second wire group 22. Thus, the first wire group 21 can easily serve as the start point of the bending of the distal end portion of the basket 30. In addition, in the state where the entirety of the basket 30 has come out of the outer tube 10 and no external force is applied to the basket 30, the radius r21 of the bent portion of the wire 20 of the first wire group 21 on the distal side with respect to the second end 62 of the first bundling portion 51 is preferably 0.1 times or more, more preferably 0.2 times or more, and further preferably 0.3 times or more the radius r22 of the bent portion of the wire 20 of the second wire group 22 on the distal side with respect to the second end 62 of the first bundling portion 51. When the lower limit value of the ratio between the radius r21 of the bent portion of the wire 20 of the first wire group 21 on the distal side with respect to the second end 62 of the first bundling portion 51 and the radius r22 of the bent portion of the wire 20 of the second wire group 22 is set to be in the above range, the bent portion of the wire 20 of the first wire group 21 is rounded, and the surface of the distal end portion of the basket 30 becomes smooth. Thus, even if the distal end portion of the basket 30 comes into contact with the tube wall or the like of the in-vivo lumen, the distal end portion of the basket 30 can be less likely to damage the tube wall or the like.
Preferably, the plurality of wires 20 of the basket 30 include the first wire group 21 and the second wire group 22, and the rigidity of the wire 20 of the first wire group 21 is lower than the rigidity of the wire 20 of the second wire group 22. When the rigidity of the wire 20 of the first wire group 21 is lower than the rigidity of the wire 20 of the second wire group 22, the first wire group 21 more easily bends than the second wire group 22. Therefore, when the state where the entirety of the basket 30 has come out of the outer tube 10 and no external force is applied to the basket 30 is established and the distal end portion of the basket 30 bends, the first wire group 21 serves as the start point of the bending. As a result, the bending of the distal end portion of the basket 30 is easily controlled.
Examples of a method for making the rigidity of the wire 20 of the first wire group 21 lower than the rigidity of the wire 20 of the second wire group 22 include: making the hardness of the material forming the wire 20 of the first wire group 21 lower than the hardness of the material forming the wire 20 of the second wire group 22; making the outer diameter of the wire 20 of the first wire group 21 smaller than the outer diameter of the wire 20 of the second wire group 22; and making the number of element wires forming the wire 20 of the first wire group 21 smaller than the number of element wires forming the wire 20 of the second wire group 22. Among them, it is preferable to make the hardness of the material forming the wire 20 of the first wire group 21 lower than the hardness of the material forming the wire 20 of the second wire group 22, thereby making the rigidity of the wire 20 of the first wire group 21 lower than the rigidity of the wire 20 of the second wire group 22. When the hardness of the material forming the wire 20 of the first wire group 21 is made lower than the hardness of the material forming the wire 20 of the second wire group 22, adjustment of the rigidity of the wire 20 of the first wire group 21 and the wire 20 of the second wire group 22 can be easily performed.
Preferably, the plurality of wires 20 of the basket 30 further include the third wire group 23, the rigidity of the wire 20 of the third wire group 23 is higher than the rigidity of the wire 20 of the first wire group 21 and lower than the rigidity of the wire 20 of the second wire group 22, and, in a cross-section perpendicular to the extending direction of the basket pusher 40, the distance D2 between the first wire group 21 and the second wire group 22 is longer than the distance D3 between the first wire group 21 and the third wire group 23. That the rigidity of the wire 20 of the third wire group 23 is higher than the rigidity of the wire 20 of the first wire group 21 and lower than the rigidity of the wire 20 of the second wire group 22 means that, among the first wire group 21, the second wire group 22, and the third wire group 23, the rigidity of the wire 20 of the first wire group 21 is the lowest and the rigidity of the wire 20 of the second wire group 22 is the highest. When the distance D2 between the first wire group 21 and the second wire group 22 is longer than the distance D3 between the first wire group 21 and the third wire group 23, among the first wire group 21, the second wire group 22, and the third wire group 23, the distance between the first wire group 21 in which the rigidity of the wire 20 is the lowest and the second wire group 22 in which the rigidity of the wire 20 is the highest can be made large. Therefore, when the basket 30 has come out of the outer tube 10 and the distal end portion of the basket 30 bends, the first wire group 21 in which the rigidity of the wire 20 is the lowest and that has a large distance from the second wire group 22 in which the rigidity of the wire 20 is the highest easily serves as the start point of the bending, and thus, the bending of the basket 30 can be easily controlled.
Preferably, the plurality of wires 20 of the basket 30 include the first wire group 21 and the second wire group 22, and the outer diameter of the wire 20 of the first wire group 21 is smaller than the outer diameter of the wire 20 of the second wire group 22. When the outer diameter of the wire 20 of the first wire group 21 is smaller than the outer diameter of the wire 20 of the second wire group 22, the first wire group 21 more easily bends than the second wire group 22. Therefore, when the entirety of the basket 30 has come out of the outer tube 10 and the distal end portion of the basket 30 bends, the first wire group 21 easily serves as the start point of the bending of the basket 30, and thus, control of the bending of the distal end portion of the basket 30 is easily performed.
The outer diameter of the wire 20 of the first wire group 21 is preferably 95% or less, more preferably 90% or less, and further preferably 85% or less of the outer diameter of the wire 20 of the second wire group 22. When the upper limit value of the ratio between the outer diameter of the wire 20 of the first wire group 21 and the outer diameter of the wire 20 of the second wire group 22 is set to be in the above range, the first wire group 21 easily bends as compared with the second wire group 22. The outer diameter of the wire 20 of the first wire group 21 is preferably 40% or more, more preferably 45% or more, and further preferably 50% or more of the outer diameter of the wire 20 of the second wire group 22. When the lower limit value of the ratio between the outer diameter of the wire 20 of the first wire group 21 and the outer diameter of the wire 20 of the second wire group 22 is set to be in the above range, the strength of the first wire group 21 can be sufficiently maintained, and the first wire group 21 is less likely to be broken during expansion or contraction of the basket 30.
Preferably, the plurality of wires 20 of the basket 30 further include the third wire group 23, the outer diameter of the wire 20 of the third wire group 23 is larger than the outer diameter of the wire 20 of the first wire group 21 and smaller than the outer diameter of the wire 20 of the second wire group 22, and in a cross-section perpendicular to the extending direction of the basket pusher 40, the distance D2 between the first wire group 21 and the second wire group 22 is longer than the distance D3 between the first wire group 21 and the third wire group 23. That the outer diameter of the wire 20 of the third wire group 23 is larger than the outer diameter of the wire 20 of the first wire group 21 and smaller than the outer diameter of the wire 20 of the second wire group 22 means that, among the first wire group 21, the second wire group 22, and the third wire group 23, the outer diameter of the wire 20 of the first wire group 21 is the smallest and the outer diameter of the wire 20 of the second wire group 22 is the largest. When the distance D2 between the first wire group 21 and the second wire group 22 is longer than the distance D3 between the first wire group 21 and the third wire group 23, among the first wire group 21, the second wire group 22, and the third wire group 23, the distance between the first wire group 21 in which the outer diameter of the wire 20 is the smallest and the second wire group 22 in which the outer diameter of the wire 20 is the largest can be made large. Therefore, when the basket 30 has come out of the outer tube 10 and the distal end portion of the basket 30 bends, the first wire group 21 in which the outer diameter of the wire 20 is the smallest and that has a large distance from the second wire group 22 in which the outer diameter of the wire 20 is the largest easily serves as the start point of the bending, and thus, the bending of the basket 30 is easily controlled.
The plurality of wires 20 of the basket 30 may further include a wire group different from the first wire group 21, the second wire group 22, and the third wire group 23. The wire group different from the first wire group 21, the second wire group 22, and the third wire group 23 refers to a wire group in which at least one of the length, rigidity, outer diameter, forming material, and the like is different from those of the wires 20 of the first wire group 21, the second wire group 22, and the third wire group 23. The number of wires of the wire group different from the first wire group 21, the second wire group 22, and the third wire group 23 may be one or may be plural as well.
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Preferably, the connection member 80 is severable. That is, preferably, the basket 30 can be detached from the basket pusher 40 by severing the connection member 80. In the case where the connection member 80 is severable, if the connection member 80 is severed after the basket 30 has been transported to a target site, the basket 30 is detached from the basket pusher 40, and thus, the basket 30 is easily indwelled in the target site.
As a method for severing the connection member 80, various methods such as a mechanical severing mechanism, fusion cutting, thermal, electrical, and chemical severing can used. Examples of the connection member 80 include rod-like objects, string-like objects, clips, members fitted to each other such as recesses and projections, etc. As the material forming the connection member 80, synthetic resins, metals, etc., can be used. The connection member 80 may be a member different from the basket 30 or the basket pusher 40, or may be a part of the basket 30 or the basket pusher 40.
Preferably, the material forming the connection member 80 has a property of melting due to heat, and the medical device 1 has a heating mechanism 90 for heating the connection member 80. When the material forming the connection member 80 has a property of melting due to heat and the medical device 1 has the heating mechanism 90, the connection member 80 can be melted and broken by the heating mechanism 90 heating the connection member 80, whereby the basket 30 can be detached from the basket pusher 40. Therefore, the basket 30 and the basket pusher 40 can be firmly connected by the connection member 80 until the heating mechanism 90 is activated, and the connection member 80 can be easily severed when the heating mechanism 90 is activated. Thus, the basket 30 can be easily and reliably indwelled.
As the material forming the connection member 80 and having a property of melting due to heat, thermoplastic resins are preferable, and among them, PVA (polyvinyl alcohol) is more preferable. When the material forming the connection member 80 is PVA, the connection member 80 can be more easily severed, and thus, the medical device 1 that is easily handled can be realized.
Preferably, the heating mechanism 90 is connected to the basket pusher 40. When the heating mechanism 90 is connected to the basket pusher 40, the connection member 80 can be heated via the basket pusher 40, and thus, it is not necessary to additionally provide a member for transmitting the heat of the heating mechanism 90 to the connection member 80. Accordingly, the size of the medical device 1 can be reduced.
Preferably, the first bundling portion 51 and the second bundling portion 52 include a radiopaque material. When the first bundling portion 51 and the second bundling portion 52 include the radiopaque material, the positions of the first bundling portion 51 and the second bundling portion 52 can be confirmed under X-ray fluoroscopy. As a result, the position of the basket 30 in a body can be grasped.
Examples of the radiopaque material include platinum, gold, tungsten, iridium, palladium, tantalum, and an alloy in which at least one of these is combined.
Each wire 20 of the basket 30 preferably includes a superelastic alloy. When each wire 20 includes a superelastic alloy, the basket 30 becomes excellent in elasticity. When the basket 30 is excellent in elasticity, the deformation amount of the basket 30 can be made large. Therefore, the basket 30 can be accommodated in the outer tube 10 having a small outer diameter, and the basket 30 can be expanded to a large extent when the basket 30 comes out of the outer tube 10.
Preferably, each wire 20 of the basket 30 includes the radiopaque material. When each wire 20 includes the radiopaque material, the position and the state of the expansion of the basket 30 can be confirmed under X-ray fluoroscopy, and the procedure is easily and smoothly performed.
As described above, the medical device of the present invention includes: an outer tube having a distal end and a proximal end; a basket disposed in an inner cavity of the outer tube and having a plurality of wires, the basket being expandable when having come out of the outer tube; and a basket pusher disposed on a proximal side with respect to the basket. The basket includes a first bundling portion at which the plurality of wires are bundled and fixed at a distal portion of the basket, and a second bundling portion at which the plurality of wires are bundled and fixed at a proximal portion of the basket. In a state where the basket is accommodated in the outer tube, the first bundling portion has a first end being an end portion on a far side with respect to the second bundling portion and a second end being an end portion on a near side with respect to the second bundling portion. In a state where an entirety of the basket has come out of the outer tube and no external force is applied to the basket, the second end is positioned on a distal side with respect to the first end. Since the medical device of the present invention has this configuration, when the entirety of the basket has come out of the outer tube and no external force is applied to the basket, the second end is positioned on the distal side with respect to the first end. Accordingly, a state where the distal end portion of the basket is bent is established, the first bundling portion of the basket is less likely to come into contact with the tube wall of the in-vivo lumen, and the tube wall can be less likely to be damaged by the first bundling portion. Further, in the state where the basket is accommodated in the outer tube, the first end is positioned on the distal side with respect to the second end. Therefore, in the outer tube, the positions of the wires forming the basket and the first bundling portion do not overlap with each other. Therefore, the diameter of the basket portion is less likely to be large, and an outer tube having a smaller diameter can be used. In addition, the force applied from the hand side to push the basket to the distal side is easily transmitted, and thus, the basket is easily released from the outer tube. As a result, a medical device that is minimally invasive can be realized.
This application claims priority to Japanese Patent Application No. 2022-034901, filed on Mar. 8, 2022. All of the contents of the Japanese Patent Application No. 2022-034901, filed on Mar. 8, 2022, are incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-034901 | Mar 2022 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/006365 | Feb 2023 | WO |
| Child | 18827328 | US |
