Patent Application
20250107816
This application claims priority to Japanese Patent Application No. 2023-169510 filed on Sep. 29, 2023, the entire content of which is incorporated herein by reference.
The present invention generally relates to a medical device including a long shaft.
As a method of treating a lesion such as stenosis or occlusion generated in a blood vessel, there is an endovascular treatment in which treatment is performed from inside the blood vessel using a device percutaneously inserted into the blood vessel. In endovascular treatment, a catheter is used for allowing a medical treatment device to reach a lesion.
For example, as the catheter for cutting and removing stenosis such as thrombus, plaque, or a calcified lesion in the blood vessel, a tube made of metal may be used as a long shaft. Since the blood vessel is bent, the shaft comes into sliding contact with a blood vessel wall when the shaft is inserted toward the lesion. When friction between the blood vessel wall and the shaft is large, torque is accumulated in the shaft as the shaft is advanced in the blood vessel.
For example, U.S. Pat. No. 8,628,549 discloses that, in a catheter including a tube made of metal, a covering material made of resin is provided on a surface of the tube made of metal. Since the covering material has a friction coefficient lower than that of metal, it is possible to control friction with the blood vessel wall to be low at the time of insertion into the blood vessel and to prevent accumulation of torque in the shaft.
However, since the covering material made of resin is provided on a surface of a distal end of the tube and this comes in close contact with the surface of the tube made of metal, flexibility of an entire shaft decreases, and passability in the blood vessel decreases.
The medical device disclosed here is capable of decreasing friction with a blood vessel wall while preventing a decrease in flexibility of a shaft.
A medical device comprises an elongated shaft that includes a distal end tube made of metal, the distal end tube provided with a distal end side rough surface portion having an uneven shape provided on an outer surface of a distal end, a proximal end side rough surface portion having an uneven shape provided on an outer surface of a proximal end, and an intermediate portion as a region between the distal end side rough surface portion and the proximal end side rough surface portion including a smooth outer surface, the distal end tube including an outer surface covered with a covering material made of resin, and the covering material being in close contact with the distal end side rough surface portion and the proximal end side rough surface portion.
In the medical device configured as described above, since the covering material enters the uneven shape of the distal end tube on the distal end side rough surface portion and the proximal end side rough surface portion and is closely fixed, it is possible to increase fixing strength of the covering material with respect to the distal end tube for decreasing friction with the blood vessel wall. In the medical device, since the outer surface of the intermediate portion of the distal end tube is smooth, the covering material does not enter the uneven shape, and a decrease in flexibility can be prevented.
According to another aspect, a medical device positionable in a biological lumen comprises: a rotatable shaft; a cutter configured to cut an object located in the biological lumen, the cutter being connected to the shaft so that rotation of the shaft results in rotation of the cutter; and an outer tubular main body in which the rotatable shaft is positioned, with the outer tubular main body having a distal end and the cutter being positioned distal of the distal end of the outer tubular main body. The outer tubular main body includes a distal end metal tube constituting a distal portion of the outer tubular main body, and the distal end metal tube including a first rough surface portion having an uneven outer surface and a second rough surface portion having an uneven outer surface, with the first rough surface portion being located distal of the second rough surface portion. The uneven outer surface of the first rough surface portion extending from a distal end of the first rough surface portion to a proximal end of the first rough surface portion, and the uneven outer surface of the second rough surface portion extending from a distal end of the second rough surface portion to a proximal end of the second rough surface portion. The proximal end of the first rough surface portion is spaced apart from the distal end of the second rough surface portion, with an intermediate portion of the distal end metal tube being located between the proximal end of the first rough surface portion and the distal end of the second rough surface portion. The intermediate portion of the distal end metal tube has an outer surface configured differently from the uneven outer surface of the first rough surface portion and the uneven outer surface of the second rough surface portion. The distal end metal tube includes a covering material made of resin, the covering material made of resin covering: i) the uneven outer surface of the first rough surface portion of the distal end metal tube; ii) the intermediate portion of the distal end metal tube; and iii) the uneven outer surface of the second rough surface portion of the distal end metal tube.
Another aspect of the disclosure involves a method for producing a distal end tube forming part of a medical device that is positionable in a biological lumen. The method comprises: performing roughening processing on first and second portions of an outer surface of a metal tube that is configured to be positioned in the biological lumen, wherein the performing of the roughening processing includes: i) performing the roughening processing on the first portion of the outer surface of the metal tube to produce a first rough surface portion having an uneven outer surface; and ii) performing the roughening processing on the second portion of the outer surface of the metal tube to produce a second rough surface portion having an uneven outer surface. The performing of the roughening processing is carried out so that: i) the first rough surface portion is located distal of the second rough surface portion; ii) the uneven outer surface of the first rough surface portion extends from a distal end of the first rough surface portion to a proximal end of the first rough surface portion; iii) the uneven outer surface of the second rough surface portion extends from a distal end of the second rough surface portion to a proximal end of the second rough surface portion; and i) the proximal end of the first rough surface portion is spaced apart from the distal end of the second rough surface portion. The roughening processing is performed on the outer surface of the first portion of the metal tube and on the outer surface of the second portion of the metal tube so that the outer surface of an intermediate portion of the metal tube is a smooth outer surface, the intermediate portion of the metal tube having the smooth outer surface being located between the proximal end of the first rough surface portion and the distal end of the second rough surface portion. The method additionally involves fixing a covering material made of resin to the metal tube so that the covering material covers the uneven outer surface of the first rough surface portion of the metal tube, the uneven outer surface of the second rough surface portion of the metal tube and the smooth outer surface of the intermediate portion of the metal tube. The covering material made of resin is in contact with the uneven outer surface of the first rough surface portion and the uneven outer surface of the second rough surface portion.
Hereinafter, an embodiment of the medical device disclosed here, representing one example of the new medical device, is described with reference to the drawings. The dimensions of the drawings may be exaggerated and different from actual dimensions for convenience of description in some cases. In the present specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numeral, and a detailed description of such features may not be repeated. In the present specification, a side to be inserted into a lumen is referred to as a “distal end side”, and a side to be operated is referred to as a “proximal end side”.
A medical device 10 according to the embodiment is inserted into a blood vessel and used for treatment of cutting and removing plaque, a calcified lesion or the like in acute lower limb ischemia or deep vein thrombosis. An object to be cut is not especially limited, and may be, for example, atheroma, thrombus or the like. Furthermore, all objects that may be present in a biological lumen may correspond to the object to be cut by the medical device 10.
As illustrated in
The drive shaft 20 is a long tube body (elongated tubular body). The drive shaft 20 is flexible and has a property capable of transmitting the rotational force applied from a proximal end side to a distal end side. The shaft portion 30 is fixed to a distal end of the drive shaft 20. As illustrated in
A constituent material from which the drive shaft 20 may be fabricated is not especially limited as long as the material is metal, and for example, stainless steel, nitinol or the like can be suitably used.
The cutter 50 is a member for cutting the object such as the plaque and calcified lesion into small pieces as illustrated in
The cutter 50 includes a large number of fine abrasive grains on a surface thereof. The cutter 50 may also be provided with a sharp blade. In the cutter 50, a first through-hole 51 located on the distal end side and a second through-hole 52 located on the proximal end side from the first through-hole 51 are formed. The first through-hole 51 and the second through-hole 52 communicate with each other and penetrate the cutter 50 in a direction along the axis X. A distal end of the shaft portion 30 is fitted in the second through-hole 52 to be coupled.
An outer peripheral surface of the cutter 50 includes a groove-shaped cutout 53 extending in the direction along the axis X. The cutout 53 functions as a flow path for conveying the cut object in a proximal end direction. The cutouts 53 are arranged, for example, at intervals of 120 degrees in a circumferential direction. Therefore, the cutter 50 includes three cutouts 53 regularly arranged in the circumferential direction. An edge of each cutout 53 is smoothly formed with a curvature. The number of the cutouts 53 is not limited to three.
It is preferable that a constituent material from which the cutter 50 may be fabricated is strong enough to cut the plaque, calcified lesion or the like, and stainless steel, nitinol, Ta, Ti, Pt, Au, W, brass, a shape memory alloy, a supersteel alloy and the like can be suitably used, for example. In a case where a soft object such as a blood vessel is to be cut, a fluorine-based polymer such as polytetrafluoroethylene (PTFE) and a tetrafluoroethylene-ethylene copolymer (ETFE), polyetheretherketone (PEEK), polyimide, polyolefin such as polyethylene and polypropylene, polyamide, polyester such as polyethylene terephthalate and the like can be suitably used.
The protection tube 60 is a flexible tubular body disposed in the drive shaft 20 and the cutter 50. The protection tube 60 is not fixed to the drive shaft 20 and the cutter 50, and is disposed so as not to rotate together with the drive shaft 20. A guide wire lumen 61 into which a guide wire is inserted is formed in the protection tube 60. The protection tube 60 prevents the guide wire that passes through the inside of the drive shaft 20 from coming into direct contact with and rubbing against the drive shaft 20. A tubular protection tube stopper 62 is coupled to a distal end of the protection tube 60. A proximal end of the protection tube stopper 62 has an outer diameter larger than that of the protection tube 60 and covers the distal end of the protection tube 60. A distal end of the protection tube stopper 62 has an outer diameter smaller than that of the proximal end of the protection tube stopper 62 and protrudes toward the distal end side from the protection tube 60. The proximal end of the protection tube stopper 62 is disposed in a gap between the shaft portion 30 and the cutter 50 in an axial direction. Therefore, the protection tube stopper 62 can restrict movement of the protection tube 60 in the axial direction, and prevent the protection tube 60 from falling.
As illustrated in
As illustrated in
The proximal end coupling portion 31 is disposed on a proximal end of the shaft portion 30 to which the distal end of the drive shaft 20 can be fitted and fixed by, for example, laser welding. The distal end coupling portion 32 is disposed on the distal end of the shaft portion 30 to which the cutter 50 can be fitted and fixed.
The first sliding portion 33 is a site disposed on the proximal end side of the distal end coupling portion 32 and rotatably supported by the first bearing 81. In the first sliding portion 33, three groove-shaped passages 40 extending in the axial direction are formed on an outer peripheral surface of a circular tube having a uniform outer diameter. The first sliding portion 33 includes three first rotary contact portions 41 that come into contact with an inner peripheral surface of the first bearing 81 between the three groove-shaped passages 40 regularly arranged in the circumferential direction. An outer diameter of the first rotary contact portion 41 is smaller than an inner diameter of the first bearing 81 to some extent. Therefore, the first rotary contact portion 41 slidably comes into contact with the inner peripheral surface of the first bearing 81.
The second sliding portion 34 is a site disposed on the distal end side of the proximal end coupling portion 31 and rotatably supported by the second bearing 82. In the second sliding portion 34, three groove-shaped passages 40 extending in the axial direction are formed on an outer peripheral surface of a circular tube having a uniform outer diameter. The second sliding portion 34 includes three second rotary contact portions 42 that come into contact with an inner peripheral surface of the second bearing 82 between the three groove-shaped passages 40 regularly arranged in the circumferential direction. An outer diameter of the second rotary contact portion 42 is smaller than an inner diameter of the second bearing 82 to some extent. Therefore, the second rotary contact portion 42 slidably comes into contact with the inner peripheral surface of the second bearing 82.
The intermediate shaft portion 35 is disposed between (axially between) the first sliding portion 33 and the second sliding portion 34. In the intermediate shaft portion 35, three groove-shaped passages 40 extending along the axis X (axial direction) are formed on an outer peripheral surface of a circular tube having a uniform outer diameter. The intermediate shaft portion 35 includes three protrusions 43 that protrudes radially outward from the first sliding portion 33 and the second sliding portion 34 between the three groove-shaped passages 40 regularly arranged in the circumferential direction.
The passage 40 forms a flow path for taking in the object cut by the cutter 50. A distal end of each passage 40 communicates with a proximal end of the cutout 53. The passage 40 is formed from the distal end side from the bearing 80 to the proximal end side of the bearing 80. The groove-shaped passage 40 may partially penetrate to an inner peripheral surface of the shaft portion 30. The passage 40 is connected to an outer peripheral surface of the shaft portion 30 on the distal end side from the bearing 80. As a result, a space of the passage 40 communicates with a space outside the shaft portion 30 on the distal end side from the bearing 80. The passage 40 is further connected to the outer peripheral surface of the shaft portion 30 on the proximal end side from the bearing 80. As a result, the space of the passage 40 communicates with the space outside the shaft portion 30 on the proximal end side from the bearing 80. Therefore, the passage 40 can take in the cut object from the outside of the shaft portion 30 on the distal end side from the bearing 80. The passage 40 can discharge the object taken in on the distal end side from the bearing 80 to the outside of the shaft portion 30 on the proximal end side from the bearing 80. By providing the passage 40 in the shaft portion 30, an intake opening 111 for taking in a cut piece can be located near the cutter 50. Furthermore, by providing the passage 40 in the shaft portion 30, friction between the shaft portion 30 and the bearing 80 is decreased, and slidability can be improved.
As illustrated in
The outer tubular main body 71 is a tubular body having flexibility. The outer tubular main body 71 extends from the handle 90 to the vicinity of the cutter 50. The outer tubular main body 71 includes a curved portion 78 in which an extending direction of the outer tubular main body 71 changes on a distal end thereof. The curved portion 78 includes a first curved portion 78a on the distal end side and a second curved portion 78b on the proximal end side curved in opposite directions, and has an S-shape. The curved portion 78 is not limited to a portion curved twice, and may be curved once or may be curved three or more times. A proximal end of the outer tubular main body 71 is fixed to the handle 90. The proximal end opening 112 is disposed on the proximal end of the outer tubular main body 71.
The support tube 72 is a circular tube made of metal fixed to the distal end of the outer tubular main body 71. The support tube 72 is provided with a support tubular main body 113 having a certain inner diameter and a stopper 114 disposed on the distal end side of the support tubular main body 113 and having an inner diameter smaller than that of the support tubular main body 113. The intake opening 111 is disposed on a distal end of the support tube 72. The stopper 114 comes into contact with a distal end surface of the first bearing 81 of the bearing 80 described later. As a result, the stopper 114 restricts the first bearing 81 from moving toward the distal end side with respect to the support tube 72 and falling from the support tube 72. The stopper 114 can restrict the movement of the first bearing 81 as long as this (the stopper 114) can come into contact with the distal end surface of the first bearing 81, so that this (the stopper 114) may be separated from the first bearing 81 to some extent. The inner diameter of the stopper 114 is preferably smaller than an outer diameter of the first bearing 81 and larger than the inner diameter of the first bearing 81. A structure of the stopper 114 is not especially limited as long as this can restrict the movement of the first bearing 81, and for example, the stopper may be partially disposed in the circumferential direction.
As illustrated in
The distal end tube 73 includes a stepped portion 73d on a proximal end thereof. A distal end of the inner tube 75a of the proximal end tube 75 abuts the stepped portion 73d of the distal end tube 73. A proximal end surface of the distal end tube 73 and a distal end surface of the outer tube 75b are butted to each other, and the proximal end of the distal end tube 73 and an outer surface of a distal end of the outer tube 75b are coupled by a coupling member 77 made of metal.
On an outer surface of the distal end tube 73, a region from a proximal end of the support tube 72 to a distal end of the coupling member 77 is covered with a covering material 74 made of resin. An outer surface of the outer tube 75b forming the proximal end tube 75 is covered with a proximal end side covering material 76. A distal end position of the proximal end side covering material 76 is located on the proximal end side from a proximal end of the coupling member 77.
As illustrated in
In
The distal end side rough surface portion 73a, a distal end position of which is located on the proximal end side from the distal end of the distal end tube 73, is not necessarily formed on the most distal end of the distal end tube 73 covered with the support tube 72. The proximal end side rough surface portion 73b, a proximal end position of which is at the same position as that of the proximal end of the distal end tube 73, is in contact with an inner surface of the coupling member 77. The coupling member 77 is joined to the distal end tube 73 with an adhesive; since the proximal end side rough surface portion 73b is formed up to the position of the coupling member 77, adhesion can be enhanced.
When the covering material 74 is fixed to the distal end tube 73, first, the distal end tube 73 is covered with a tubular covering material 74 and heated at first temperature (for example, about 210° C.) to shrink the covering material 74. At that time, the covering material 74 enters (is positioned in) the uneven shape of the distal end side rough surface portion 73a and the proximal end side rough surface portion 73b having the uneven shape and comes into close contact. As illustrated in
The distal end side rough surface portion 73a and the proximal end side rough surface portion 73b of the distal end tube 73 are desirably disposed in a portion other than the first curved portion 78a and the second curved portion 78b in the long axis (axial) direction. For example, the distal end side rough surface portion 73a can be disposed on the distal end side from the first curved portion 78a, and the proximal end side rough surface portion 73b can be disposed on the proximal end side from the second curved portion 78b. One of the distal end side rough surface portion 73a and the proximal end side rough surface portion 73b can be disposed between the first curved portion 78a and the second curved portion 78b.
The distal end tube 73 and the outer tube 75b of the proximal end tube 75 are formed of metal as described above. It is preferable that a constituent material thereof is strong to some extent, and stainless steel, nitinol, Ta, Ti, Pt, Au, W, a shape memory alloy and the like can be suitably used, for example.
The covering material 74 is formed of a flexible resin having excellent slidability. The covering material 74 is desirably melted at certain temperature. In the present embodiment, polyolefin is used as the covering material 74. The covering material 74 may be formed of another resin having the above-described property, and for example, a thermoplastic resin such as polyamide or polyurethane can be appropriately combined with a hydrophilic coating or the like.
The proximal end side covering material 76 can be formed of a resin harder than the covering material 74 that covers the distal end tube 73. As such resin, for example, a nylon elastomer, for example, Pebax (registered trademark) can be used. As a result, rigidity of the outer tubular shaft 70 can be increased, and operability including torque transmission performance can be made excellent. However, the material of the proximal end side covering material 76 may be another resin, and for example, PTFE, PET and the like can be used.
It is preferable that a constituent material from which the support tube 72 is fabricated is strong to some extent, and for example, stainless steel, nitinol, Ta, Ti, Pt, Au, W, a shape memory alloy, an engineering plastic such as polyether ether ketone (PEEK), and a combination thereof can be suitably used.
As illustrated in
As illustrated in
A proximal end of the outer tubular main body 71 is fixed to a distal end of the casing 91. In the casing 91, an intake space 95 communicating with the intake port 93 and a liquid delivery space 97 communicating with the liquid delivery port 96 are formed. The proximal end opening 112 of the outer tubular main body 71 is rotatably disposed in the intake space 95.
The rotation operation portion 94 is a site operated by an operator with his/her finger to apply rotational torque to the outer tubular shaft 70. The rotation operation portion 94 is rotatably coupled to the distal end of the casing 91. The rotation operation portion 94 is fixed to an outer peripheral surface of the proximal end of the outer tubular main body 71.
The drive unit 92 is, for example, a hollow motor. The drive unit 92 is rotated by a battery not illustrated or externally supplied power. The drive shaft 20 is fixed to a hollow drive rotor of the hollow motor. A rotation speed of the drive unit 92 is not especially limited, and is 5,000 to 200,000 rpm, for example. The configuration of the drive unit 92 is not especially limited.
The intake port 93 conveys an object, liquid or the like in the intake space 95 to the outside. An intake drive source such as a pump or a syringe can be connected to the intake port 93. From the liquid delivery port 96, fluid can be delivered to the inside of the outer tubular shaft 70 via the liquid delivery space 97.
Next, a method of using the medical device 10 according to the present embodiment will be described using, as an example, a case where the lesion such as the plaque and calcified lesion in the blood vessel is cut and taken in.
First, the operator inserts a guide wire W into the blood vessel and allows the same to reach the vicinity of a lesion S. Next, the operator inserts a proximal end of the guide wire W into the guide wire lumen 61 of the medical device 10. Thereafter, as illustrated in
Next, the operator operates the drive unit 92. As a result, the drive shaft 20 rotates, and the cutter 50 and the shaft portion 30 rotate together with the drive shaft 20. As a result, the operator can cut the lesion S by the cutter 50. At that time, especially in the curved portion 78, the inner surface of the outer tubular shaft 70 and the drive shaft 20 rotating at a high speed might come into contact with each other, but since the distal end covering portion 25 made of resin is provided on the distal end of the drive shaft 20, friction between the drive shaft 20 and the outer tubular shaft 70 can be controlled to be low.
The operator can reciprocate the outer tubular shaft 70 in a longitudinal direction of the blood vessel by moving the entire handle 90 or the outer tubular shaft 70 exposed to the outside of the body. As a result, the operator can cut the lesion S in the longitudinal direction of the blood vessel by the cutter 50.
The additional coil 23 can generate the flow of fluid that conveys an object toward the proximal end side in the intake lumen 110 as the drive shaft 20 rotates. Therefore, the lesion S cut by the cutter 50 becomes debris, and is taken in the intake lumen 110 from the distal end opening. The debris can pass through the cutout 53 of the cutter 50 and efficiently enter the passage 40 communicating with the cutout 53. The debris can enter the passage 40 from the gap G between the cutter 50 and the support tube 72. The passage 40 can be formed spirally around the axis X. As a result, when the drive shaft 20 rotates by the rotating passage 40, the spiral passage 40 that rotates can function as an Archimedean screw (screw pump). As a result, the passage 40 can smoothly convey the object or fluid inside the intake lumen 110 toward the proximal end side.
The debris that enters the passage 40 on the distal end side from the first bearing 81 moves toward the proximal end side inside the first bearing 81 and the second bearing 82. Thereafter, the debris moves from the passage 40 to the outer peripheral surface side of the shaft portion 30 on the proximal end side from the second bearing 82. Thereafter, the debris moves toward the proximal end side in the intake lumen 110 and is discharged through the intake space 95 and the intake port 93. After the cutting of the lesion S and the intake of the debris are completed, the operator stops the operation of the drive unit 92. As a result, the cutting of the lesion S and the discharge of the debris stop. Thereafter, the operator removes the medical device 10 from the blood vessel, and the treatment is completed.
As described above, (1) a medical device 10 according to the present embodiment is a medical device 10 including a long shaft 70, the shaft 70 including a distal end tube 73 made of metal, the distal end tube 73 provided with a distal end side rough surface portion 73a having an uneven shape provided on an outer surface of a distal end, a proximal end side rough surface portion 73b having an uneven shape provided on an outer surface of a proximal end, and an intermediate portion 73c as a region between the distal end side rough surface portion 73a and the proximal end side rough surface portion 73b including a smooth outer surface, the distal end tube 73 including an outer surface covered with a covering material 74 made of resin, and the covering material 74 being in close contact with the distal end side rough surface portion 73a and the proximal end side rough surface portion 73b. In the medical device 10 configured as described above, since the covering material 74 enters the uneven shape of the distal end tube 73 on the distal end side rough surface portion 73a and the proximal end side rough surface portion 73b and is closely fixed, it is possible to increase fixing strength of the covering material 74 with respect to the distal end tube 73 for decreasing friction with the blood vessel wall. In the medical device 10, since the outer surface of the intermediate portion 73c of the distal end tube 73 is smooth, the covering material 74 does not enter the uneven shape, and a decrease in flexibility can be prevented.
The new medical device disclosed here is not limited to the embodiment described above, and various modifications can be made by those skilled in the art within the technical idea of the present invention. The medical device 10 is not limited to the device that cuts and removes the object in the blood vessel, and the present invention can also be applied to other types of devices including the tube made of metal on the distal end such as an ultrasonic catheter, for example.
The detailed description above describes embodiments of a medical device, operational method and method of manufacture representing examples of the new medical device, operation and manufacturing method disclosed here. The invention is not limited, however, to the precise embodiments and variations described. Various changes, modifications and equivalents can be effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents that fall within the scope of the claims are embraced by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-169510 | Sep 2023 | JP | national |
