Medical device

Abstract

To provide a medical device that can reduce abrasion of a rotary drive shaft.SOLUTION: A medical device 10 includes: a long drive shaft 20 that rotates about an axis center along a longitudinal direction; and a long outer pipe shaft 70 provided on the outer side of the drive shaft 20. The tip end part of the drive shaft 20 is covered with a tip end covering part 25 having an outer surface made of a resin. The drive shaft 20 is a pipe formed from a plurality of wire materials connected in a spiral manner about the axis center. At least part of the tip end covering part 25 has penetrated into the drive shaft 20 through between the wire materials.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to medical devices having elongate shafts. [Background technology]

[0002] One method for treating lesions such as stenosis and blockage in blood vessels is endovascular treatment, which uses a device percutaneously inserted into the blood vessel to perform treatment from within the blood vessel. In endovascular treatment, a catheter is used to deliver a treatment site to the lesion.

[0003] For example, the catheter shown in Patent Document 1 can cut and remove stenosis such as thrombus, plaque, and calcified lesions in blood vessels. This catheter has a metal drive shaft inside a metal outer tube shaft, and the drive shaft rotates around its axis. The outer tube shaft has a curved portion at its tip, and the surgeon can change the direction of the cutting portion provided at the tip of the outer tube shaft by operating the outer tube shaft to rotate it, so that the cutting portion can be positioned toward the lesion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 8,628,549 Summary of the Invention [Problem to be solved by the invention]

[0005] When the outer tubular shaft has a curved portion and the rotating drive shaft is disposed inside the curved portion, the drive shaft is bent to have the shortest distance inside the outer tubular shaft, and is therefore likely to come into contact with the inner surface of the outer tubular shaft. Since at least a portion of the outer tubular shaft and the drive shaft are made of metal, friction between the two may reduce the durability of the drive shaft and may generate metal powder.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide a medical device that can reduce wear on a rotating drive shaft. [Means for solving the problem]

[0007] A medical device that achieves the above objective is a medical device having a long drive shaft that rotates around an axis along the longitudinal direction as a central axis, and a long outer tube shaft that is arranged on the outside of the drive shaft, and the tip of the drive shaft has an outer surface covered with a resin tip covering. Effect of the Invention

[0008] In the medical device configured as described above, the tip of the drive shaft is covered with resin, which reduces wear when the tip of the drive shaft comes into contact with the inner surface of the outer tube shaft, allowing the drive shaft to rotate smoothly. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a front view showing a medical device according to an embodiment. [Diagram 2] 1 is a perspective view showing the tip portion of a medical device with the cutting portion and the containing portion visible. FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing the tip of a medical device. [Figure 4] 4 shows the distal end of a medical device, where (a) is a cross-sectional view taken along line AA in FIG. 3, (b) is a cross-sectional view taken along line BB in FIG. 3, and (c) is a cross-sectional view taken along line CC in FIG. [Diagram 5] FIG. 4 is a cross-sectional view showing a portion of the medical device closer to the base end than FIG. 3, with the drive shaft shown in front view. [Figure 6] 11 is a cross-sectional view showing a state in which the drive shaft and the tip end of the tip covering portion are in close contact with each other. FIG. [Figure 7] 13 is a cross-sectional view showing a state in which the drive shaft and the base end of the tip covering portion are in close contact with each other. FIG. [Figure 8]FIG. 13 is a schematic diagram showing a state in which cutting is being performed by the medical device. [Figure 9] 13 is a cross-sectional view of the vicinity of a connection portion between a drive shaft and a shaft portion when the outer tubular shaft does not have a curved portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that dimensions in the drawings may be exaggerated and may differ from actual dimensions for convenience of explanation. In addition, in this specification and the drawings, components having substantially the same functions are given the same reference numerals to avoid duplicated explanation. In this specification, the side inserted into a lumen is referred to as the "distal side" and the side operated is referred to as the "base side".

[0011] The medical device 10 according to the embodiment is inserted into a blood vessel and used in a procedure for cutting and removing plaque, calcified lesions, and the like, in acute lower limb ischemia and deep vein thrombosis. The object to be cut is not particularly limited, and may be, for example, an atheroma, a thrombus, and the like. Furthermore, all objects that may exist in a biological lumen may be objects to be cut by the medical device 10.

[0012] 1 to 3, the medical device 10 includes a rotatable rotating structure 11, a housing 12 that rotatably houses the rotating structure 11, and a handle 90 that is operated by an operator. The rotating structure 11 includes a drive shaft 20 that transmits a rotational force, an axle 30 that is rotatably supported by the housing 12, a cutting section 50 that cuts plaque or calcified lesions, and a protective tube 60 that is housed in the drive shaft 20. The housing 12 includes an outer tube shaft 70 that houses the drive shaft 20, and a bearing 80 that rotatably supports the axle 30.

[0013] The drive shaft 20 is a long tube. The drive shaft 20 is flexible and has a characteristic that a rotational force acting from the base end side can be transmitted to the tip end side. A shaft portion 30 is fixed to the tip end of the drive shaft 20. As shown in FIG. 5, the drive shaft 20 is a tube in which a plurality of wires 21 are arranged and connected in a spiral shape around the axis X of the rotating structure 11. The drive shaft 20 has an additional coil 23 wound in a spiral shape on the outer circumferential surface from a position on the base end side of the tip toward the base end side. The additional coil 23 can generate a flow of fluid that conveys an object toward the base end side as the drive shaft 20 rotates. The axis X is the structural center axis of the rotating structure 11 and is also the central axis of the rotating structure 11. The base end of the drive shaft 20 is located inside the handle portion 90. The drive shaft 20 does not have to be made of wire.

[0014] The material of the drive shaft 20 is not particularly limited as long as it is a metal, but for example, stainless steel, nitinol, etc. can be suitably used.

[0015] As shown in Figs. 1 to 3, the cutting unit 50 is a member for cutting and reducing the size of objects such as plaque and calcified lesions. Therefore, "cutting" means applying a force to a contacting object to reduce the size of the object. The method of applying the force in cutting and the shape and form of the object after cutting are not limited.

[0016] The cutting part 50 has a large number of minute abrasive grains on the surface. Alternatively, the cutting part 50 may have a sharp blade. The cutting part 50 has a first through hole 51 located on the tip side and a second through hole 52 located on the base end side of the first through hole 51. The first through hole 51 and the second through hole 52 communicate with each other and penetrate the cutting part 50 in the direction along the axis X. The tip part of the shaft part 30 is fitted and connected inside the second through hole 52.

[0017] The outer peripheral surface of the cutting part 50 has groove-shaped notches 53 extending in a direction along the axis X. The notches 53 function as flow paths for transporting the cut object toward the base end. The notches 53 are arranged, for example, every 120 degrees in the circumferential direction. Thus, the cutting part 50 has three notches 53 evenly arranged in the circumferential direction. The edges of each of the notches 53 are smoothly formed with a curvature. The number of the notches 53 is not limited to three.

[0018] The constituent material of the cutting portion 50 is preferably strong enough to cut plaque, calcified lesions, etc., and suitable materials for use include stainless steel, nitinol, Ta, Ti, Pt, Au, W, brass, shape memory alloys, super steel alloys, etc. When cutting soft objects such as thrombi, suitable materials for use include fluorine-based polymers such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene-ethylene copolymer (ETFE), polyolefins such as polyether ether ketone (PEEK), polyimide, polyethylene, and polypropylene, and polyesters such as polyamide and polyethylene terephthalate.

[0019] The protective tube 60 is a flexible tube disposed inside the drive shaft 20 and the cutting section 50. The protective tube 60 is not fixed to the drive shaft 20 and the cutting section 50, and is disposed so as not to rotate together with the drive shaft 20. The protective tube 60 is formed with a guide wire lumen 61 through which a guide wire passes. The protective tube 60 prevents the guide wire passing through the inside of the drive shaft 20 from directly contacting and rubbing against the drive shaft 20. A cylindrical protective tube stopper 62 is connected to the tip of the protective tube 60. The base end of the protective tube stopper 62 has an outer diameter larger than that of the protective tube 60, and covers the tip of the protective tube 60. The tip of the protective tube stopper 62 has an outer diameter smaller than that of the base end of the protective tube stopper 62, and protrudes further toward the tip side than the protective tube 60. The base end of the protective tube stopper 62 is disposed in the gap between the shaft section 30 and the cutting section 50 in the axial direction. Therefore, the protective tube stopper 62 limits the movement of the protective tube 60 in the axial direction, and prevents the protective tube 60 from falling off.

[0020] 2 to 4, the bearing 80 has a first bearing 81 and a second bearing 82, each of which is ring-shaped. The first bearing 81 and the second bearing 82 are disposed apart from each other along the axis X inside the support tube 72. The first bearing 81 and the second bearing 82 have the same shape, but may have different shapes.

[0021] As shown in Figs. 2 to 4, the shaft portion 30 is a portion that supports the rotating structure 11 rotatably relative to the accommodation portion 12. The shaft portion 30 includes a base end connecting portion 31 that is connected to the drive shaft 20, and a tip connecting portion 32 that is connected to the cutting portion 50. The shaft portion 30 further includes a first sliding portion 33 that is supported by a first bearing 81, a second sliding portion 34 that is supported by a second bearing 82, and an intermediate shaft portion 35 that is disposed between the first sliding portion 33 and the second sliding portion 34. The shaft portion 30 has at least one passage 40 (three in this embodiment) that extends along the axis X formed therein.

[0022] The base end connecting part 31 is disposed at the base end of the shaft part 30, and the tip end of the drive shaft 20 can be fitted thereto and fixed by means of laser welding or the like. The tip connecting part 32 is disposed at the tip end of the shaft part 30, and the cutting part 50 can be fitted thereto and fixed.

[0023] The first sliding portion 33 is disposed on the base end side of the tip connecting portion 32 and is rotatably supported by the first bearing 81. The first sliding portion 33 has three groove-like passages 40 extending in the axial direction formed on the outer peripheral surface of a circular tube having a uniform outer diameter. The first sliding portion 33 has three first rotational contact portions 41 that contact the inner peripheral surface of the first bearing 81 between the three groove-like passages 40 that are evenly arranged in the circumferential direction. The outer diameter of the first rotational contact portions 41 is slightly smaller than the inner diameter of the first bearing 81. Therefore, the first rotational contact portions 41 slidably contact the inner peripheral surface of the first bearing 81.

[0024] The second sliding portion 34 is disposed on the tip side of the base end connecting portion 31 and is rotatably supported by the second bearing 82. The second sliding portion 34 has three groove-like passages 40 extending in the axial direction formed on the outer circumferential surface of a circular tube having a uniform outer diameter. The second sliding portion 34 has three second rotational contact portions 42 that contact the inner circumferential surface of the second bearing 82 between the three groove-like passages 40 that are evenly arranged in the circumferential direction. The outer diameter of the second rotational contact portions 42 is slightly smaller than the inner diameter of the second bearing 82. Therefore, the second rotational contact portions 42 slidably contact the inner circumferential surface of the second bearing 82.

[0025] The intermediate shaft portion 35 is disposed between the first sliding portion 33 and the second sliding portion 34. The intermediate shaft portion 35 has three groove-like passages 40 extending along the axis X formed on the outer peripheral surface of a circular tube having a uniform outer diameter. The intermediate shaft portion 35 has three protruding portions 43 that protrude radially outward beyond the first sliding portion 33 and the second sliding portion 34 between the three groove-like passages 40 that are evenly disposed in the circumferential direction.

[0026] The passage 40 forms a flow path that takes in the object cut by the cutting unit 50. The tip of each passage 40 communicates with the base end of the notch 53. The passage 40 is formed from the tip side to the base side of the bearing 80. The groove-shaped passage 40 may partially penetrate to the inner peripheral surface of the shaft unit 30. The passage 40 is connected to the outer peripheral surface of the shaft unit 30 on the tip side of the bearing 80. As a result, the space of the passage 40 communicates with the space outside the shaft unit 30 on the tip side of the bearing 80. Furthermore, the passage 40 is connected to the outer peripheral surface of the shaft unit 30 on the base side of the bearing 80. As a result, the space of the passage 40 communicates with the space outside the shaft unit 30 on the base side of the bearing 80. Therefore, the passage 40 can take in the cut object from the outside of the shaft unit 30 on the tip side of the bearing 80. And, the passage 40 can release the object taken in on the tip side of the bearing 80 to the outside of the shank 30 on the base side of the bearing 80. Also, by providing the passage 40 in the shank 30, the intake opening 111 for taking in the cutting chips can be positioned near the cutting portion 50. Furthermore, by providing the passage 40 in the shank 30, friction between the shank 30 and the bearing 80 can be reduced, and the sliding property can be improved.

[0027] As shown in Figs. 1 to 3, the outer tube shaft 70 is a tube that houses the drive shaft 20 and the protective tube 60. The outer tube shaft 70 has an outer tube main body 71 and a support tube 72 fixed to the tip side of the outer tube main body 71. Between the outer tube shaft 70 and the drive shaft 20, an intake lumen 110 is formed for taking in objects that have been cut and reduced in size, such as plaque and calcified lesions. The outer tube shaft 70 has an intake opening 111 at its tip for taking in the cut object and the liquid discharged from the drive shaft 20. The tip of the outer tube shaft 70 is disposed on the base end side from the base end of the cutting section 50 with a predetermined gap G therebetween. The gap G has a length exceeding 0 along the axis X when the rotating structure section 11 is disposed at the most base end side with respect to the housing section 12. Therefore, the tip of the outer tube shaft 70 is prevented from contacting the cutting section 50. The outer tubular shaft 70 has a proximal end opening 112 that opens inside the handle portion 90 at its proximal end.

[0028] The outer tube body 71 is a flexible tube. The outer tube body 71 extends from the handle portion 90 to the vicinity of the cutting portion 50. The outer tube body 71 has a curved portion 78 at the tip portion where the direction in which the outer tube body 71 extends changes. The curved portion 78 has a first curved portion 78a at the tip side and a second curved portion 78b at the base end side that curve in opposite directions, and has an S-shape. The curved portion 78 is not limited to being curved twice, and may be curved once or three or more times. The base end of the outer tube body 71 is fixed to the handle portion 90. The base end opening 112 is disposed at the base end of the outer tube body 71.

[0029] The support tube 72 is a metal circular tube fixed to the tip of the outer tube body 71. The support tube 72 includes a support tube body 113 having a certain inner diameter, and a stopper 114 arranged on the tip side of the support tube body 113 and having an inner diameter smaller than that of the support tube body 113. The intake opening 111 is arranged at the tip of the support tube 72. The stopper 114 comes into contact with the tip surface of a first bearing 81 of a bearing 80 described later. This allows the stopper 114 to restrict the first bearing 81 from moving toward the tip side relative to the support tube 72 and falling off the support tube 72. Note that the stopper 114 may be somewhat separated from the first bearing 81 as long as it can come into contact with the tip surface of the first bearing 81, since it can restrict the movement of the first bearing 81. It is preferable that the inner diameter of the stopper 114 is smaller than the outer diameter of the first bearing 81 and larger than the inner diameter. The structure of the stopper 114 is not particularly limited as long as it can limit the movement of the first bearing 81, and may be arranged partially in the circumferential direction, for example.

[0030] 5, the outer tube main body 71 has a metal distal tube 73 and a proximal tube 75 disposed on the proximal side of the distal tube 73. A curved portion 78 of the outer tube shaft 70 is formed within the range of the distal tube 73. The proximal tube 75 has a resin inner tube 75a having a braided body formed of thin metal wires therein, and a metal outer tube 75b covering the outer surface of the inner tube 75a.

[0031] The distal end tube 73 has a step 73d at its proximal end. The distal end of the inner tube 75a of the proximal tube 75 abuts against the step 73d of the distal end tube 73. The proximal end surface of the distal end tube 73 and the distal end surface of the outer tube 75b are butted together, and the proximal end of the distal end tube 73 and the outer surface of the distal end of the outer tube 75b are connected by a metal connecting member 77.

[0032] The outer surface of distal tube 73, in the region from the base end of support tube 72 to the tip of connecting member 77, is covered with a resin covering material 74. The outer surface of outer tube 75b constituting proximal tube 75 is covered with a proximal side covering material 76. The tip position of proximal side covering material 76 is located on the proximal side of the base end of connecting member 77.

[0033] As described above, the distal tube 73 and the outer tube 75b of the proximal tube 75 are made of metal. The constituent material preferably has a certain degree of strength, and for example, stainless steel, nitinol, Ta, Ti, Pt, Au, W, shape memory alloys, etc. can be suitably used.

[0034] The coating material 74 is made of a resin that is flexible and has good slipperiness. It is also preferable that the coating material 74 melts at a certain temperature. In this embodiment, polyolefin is used as the coating material 74. However, the coating material 74 may be made of other resins having the above-mentioned characteristics, and for example, a thermoplastic resin such as polyamide or polyurethane may be appropriately combined with a hydrophilic coating or the like.

[0035] The base end covering material 76 can be made of a resin harder than the covering material 76 that covers the distal tube 73. As such a resin, for example, a nylon-based elastomer, for example, Pebax (registered trademark), can be used. This increases the rigidity of the outer tube shaft 70 and improves operability including torque transmission. However, the base end covering material 76 may be made of other resins, such as PTFE or PET.

[0036] The material constituting the support tube 72 preferably has a certain degree of strength, and suitable materials for use include, for example, stainless steel, nitinol, Ta, Ti, Pt, Au, W, shape memory alloys, engineering plastics such as polyether ether ketone (PEEK), and combinations thereof.

[0037] As shown in Fig. 5, the outer surface of the distal end of the drive shaft 20 is covered with a resin distal end covering part 25. The distal end covering part 25 extends continuously along the longitudinal direction from the proximal end surface of the shaft part 30 to the proximal side of the joint part between the distal end tube 73 and the proximal end tube 75. The distal end covering part 25 extends in the longitudinal direction to include the range of the curved part 78 of the outer tube shaft 70. Since the outer tube shaft 70 has an S-shaped curved part 78, the drive shaft 20 is likely to come into contact with the first curved part 78a and the second curved part 78b. At this time, the distal end covering part 25 comes into contact with the inner surface of the outer tube shaft 70, so that wear of the drive shaft 20 can be reduced. Furthermore, as described above, the inner tube 75a of the base end tube 75 has a metal braid inside, and the braid may be exposed on the inside at the tip. However, since the tip covering portion 25 is also provided at the joint between the tip tube 72 and the base end tube 75, the exposed braid can be prevented from coming into direct contact with the metal parts of the drive shaft 20, thereby improving the durability of the drive shaft 20.

[0038] The base end position of the distal end covering portion 25 is located on the distal side of the distal end position of the additional coil 23 of the drive shaft 20, and is not provided in the range where the additional coil 23 is arranged. Therefore, in the range where the additional coil 23 is provided, it is possible to prevent the flow path through which the fluid containing the object flows from being narrowed.

[0039] When fixing the tip covering part 25 to the drive shaft 20, first, the tubular tip covering part 25 is placed over the tip part of the drive shaft 20 and heated at a certain temperature (for example, about 230°C) for a certain period of time. As a result, the surface of the tip covering part 25 melts and a part of it penetrates into the inside of the drive shaft 20 between the wires 21, as shown in Fig. 6. This allows the tip covering part 25 and the drive shaft 20 to be fixed in close contact with each other.

[0040] Next, the proximal end 25b of the tip covering part 25 is covered with a fluorine-based heat-shrinkable tube that can be removed after shrinkage, and heated at a certain temperature (for example, about 230°C) for a certain time. As a result, the surface of the proximal end 25b of the tip covering part 25 melts and penetrates deeper into the inside of the drive shaft 20 between the wires 21, as shown in FIG. 7. As shown in FIG. 5, the range (area A) of the tip covering part 25 where the curved part 78 of the outer tube shaft 70 is formed is the tip part 25a, and the proximal end 25b is the range (area B) on the proximal side of the curved part 78. The drive shaft 20 is likely to be mechanically damaged by the braid of the inner tube 75a described above, etc., in the part on the proximal side of the curved part 78. Since the proximal end 25b of the tip covering part 25 penetrates deeper into the drive shaft 20 than the tip part 25a, it is possible to prevent the tip covering part 25 from peeling off in the part of the outer tube shaft 70 on the proximal side of the curved part 78 that is linear.

[0041] The depth to which tip covering portion 25 extends into drive shaft 20, i.e., the depth to which tip covering portion 25 extends from imaginary plane P connecting the surfaces furthest from the axis of wire 21, is more than 0 μm and not more than 100 μm. As shown in Figures 6 and 7, depth H2 at base end 25b is greater than depth H1 at tip end 25a.

[0042] The tip covering portion 25 extends into the inside of the drive shaft 20 over its entire length, and therefore extends continuously into the inside of the drive shaft 20 from a position distal to the curved portion 78 to a position proximal to the curved portion 78. This reliably reduces friction when the drive shaft 20 and the outer tube shaft 70 come into contact at the curved portion 78. The tip covering portion 25 does not have to cover the tip of the drive shaft 20 continuously along the longitudinal direction, and may be formed to cover most of the coil-shaped surface portion of the drive shaft 20.

[0043] The tip covering portion 25 is made of a resin that is flexible and melts at a certain temperature. In this embodiment, polyolefin is used as the tip covering portion 25. However, the tip covering portion 25 may be made of other resins having the above-mentioned characteristics, for example, a thermoplastic resin such as polyamide or polyurethane may be appropriately combined with a hydrophilic coating or the like.

[0044] As shown in FIG. 1, the handle portion 90 includes a casing 91, a drive portion 92, an intake port 93, a rotation operation portion 94, and a liquid delivery port 96.

[0045] The base end of the outer tube body 71 is fixed to the tip end of the casing 91. The casing 91 has an intake space 95 communicating with an intake port 93 and a liquid delivery space 96 communicating with a liquid delivery port 96 formed therein. A base end opening 112 of the outer tube body 71 is rotatably disposed in the intake space 95.

[0046] The rotation operation unit 94 is a part that is operated by the surgeon's fingers to apply a rotational torque to the outer tube shaft 70. The rotation operation unit 94 is rotatably connected to the tip end of the casing 91. The rotation operation unit 94 is fixed to the outer peripheral surface of the base end of the outer tube main body 71.

[0047] The driving unit 92 is, for example, a hollow motor. The driving unit 92 rotates by power supplied from a battery (not shown) or an external source. The drive shaft 20 is fixed to a hollow driving rotor of the hollow motor. The rotation speed of the driving unit 92 is not particularly limited, but is, for example, 5,000 to 200,000 rpm. The configuration of the driving unit 92 is not particularly limited.

[0048] The intake port 93 transports objects, liquids, etc., inside the intake space 95 to the outside. From the liquid delivery port 96, a fluid can be delivered to the inside of the outer tube shaft 70 via a liquid delivery space 97.

[0049] Next, a method of using the medical device 10 according to this embodiment will be described using an example in which a lesion such as plaque or a calcified lesion in a blood vessel is cut and taken in.

[0050] First, the surgeon inserts the guidewire W into the blood vessel and reaches the vicinity of the lesion S. Next, the surgeon inserts the base end of the guidewire W into the guidewire lumen 61 of the medical device 10. Thereafter, as shown in FIG. 8, the cutting section 50 is moved to the vicinity of the lesion S using the guidewire W as a guide. At this time, since the distal end tube 72 constituting the distal end of the outer tube shaft 70 is provided with a resin coating material 76, friction with the blood vessel wall can be kept low. Therefore, when the outer tube shaft 70 is inserted into a blood vessel path that is bent multiple times, accumulation of torque in the outer tube shaft 70 can be suppressed.

[0051] Next, the surgeon operates the drive unit 92. This rotates the drive shaft 20, and the cutting unit 50 and the shaft unit 30 rotate together with the drive shaft 20. This allows the surgeon to cut the lesion S with the cutting unit 50. At this time, the inner surface of the outer tube shaft 70 and the drive shaft 20 rotating at high speed may come into contact with each other, particularly at the curved portion 78. However, since the resin tip covering portion 25 is provided at the tip of the drive shaft 20, the friction between the drive shaft 20 and the outer tube shaft 70 can be kept low.

[0052] Since the outer tube shaft 70 has an S-shaped curved portion 78, the surgeon can change the direction of the curved portion 78 of the outer tube shaft 70 and change the position of the cutting portion 50 by rotating the rotation operation portion 94 while holding the casing 91. As shown in FIG. 8, when the cutting portion 50 is in a position to cut the lesion portion S, the curved portion 78 abuts against the blood vessel wall. When the drive shaft 20 rotates in this state, the tip of the drive shaft 20 is supported by the curved portion 78 abutting against the blood vessel wall as a bearing, so that even if the rotation axis is misaligned, revolution around the axis is unlikely to occur. For this reason, as shown in FIG. 3, the base end connecting portion 31 of the shaft portion 30 that fixes the tip of the drive shaft 20 is formed shallow. If the outer tube shaft 70 does not have the curved portion 78, there is no portion that supports the drive shaft 20, and revolution around the axis occurs when the rotation axis is misaligned. 9, by forming the base end connecting part 31 of the shaft part 30 deep and storing the tip part of the drive shaft 20 longer in the longitudinal direction in the base end connecting part 31, it is possible to reduce metal fatigue of the drive shaft 20 due to the revolution motion and suppress the possibility of breakage. When the bent part 78 is provided, the base end connecting part 31 can be formed shallow, so that the decrease in flexibility in this part can be suppressed.

[0053] In addition, the surgeon can move the entire handle portion 90 or the outer tube shaft 70 exposed to the outside of the body to reciprocate the outer tube shaft 70 along the longitudinal direction of the blood vessel. This allows the surgeon to cut the lesion S along the longitudinal direction of the blood vessel with the cutting portion 50.

[0054] The additional coil 23 can generate a flow of fluid that transports objects in the intake lumen 110 toward the base end side as the drive shaft 20 rotates. Therefore, the lesion S cut by the cutting part 50 becomes debris and is taken into the intake lumen 110 from the tip opening. The debris can pass through the notch part 53 of the cutting part 50 and efficiently enter the passage 40 communicating with the notch part 53. In addition, the debris can enter the passage 40 from the gap G between the cutting part 50 and the support tube 72. The passage 40 may be formed in a spiral shape centered on the axis X. As a result, when the drive shaft 20 is rotated by the rotating passage 40, the rotating spiral passage 40 can function as an Archimedes screw (screw pump). As a result, the passage 40 can smoothly transport objects and fluids inside the intake lumen 110 to the base end side.

[0055] The debris that has entered the passage 40 distally of the first bearing 81 moves proximally inside the first bearing 81 and the second bearing 82. The debris then moves proximally from the passage 40 to the outer circumferential surface of the shaft portion 30 proximally of the second bearing 82. The debris then moves proximally through 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 surgeon stops the operation of the drive unit 92. This stops the cutting of the lesion S and the discharge of the debris. The surgeon then removes the medical device 10 from the blood vessel to complete the procedure.

[0056] As described above, the medical device 10 according to this embodiment (1) is a medical device 10 having a long drive shaft 20 that rotates around an axis along the longitudinal direction as a central axis, and a long outer tube shaft 70 that is disposed on the outside of the drive shaft 20, and the outer surface of the tip of the drive shaft 20 is covered with a resin tip covering part 25. In the medical device 10 configured in this manner, since the tip of the drive shaft 20 is covered with resin, it is possible to reduce wear when the tip of the drive shaft 20 comes into contact with the inner surface of the outer tube shaft 70, and it is possible to smoothly rotate the drive shaft 20.

[0057] (2) In the medical device 10 of (1) above, the drive shaft 20 is a tube formed by arranging a plurality of wires and connecting them in a spiral shape around the axis, and at least a part of the tip covering part 25 may enter the inside of the drive shaft 20 between the wires. This increases the contact area between the drive shaft 20 and the tip covering part 25 in the medical device 10, and the tip covering part 25 can be firmly fixed to the drive shaft 20 so as not to peel off.

[0058] (3) In the medical device 10 of (2) above, the tip covering part 25 may have a base end and a tip end, and the base end may extend deeper into the drive shaft 20 than the tip end. This allows the medical device 10 to ensure the flexibility of the tip end of the drive shaft 20 while further suppressing peeling at the base end of the tip covering part 25.

[0059] (4) In the medical device of (3) above, the outer tubular shaft 70 may have a curved portion 78 at its distal end, and the proximal end of the distal covering portion 25 may be located on the proximal side of the curved portion 78. In this way, when the drive shaft 20 comes into contact with the outer tubular shaft 70 at the curved portion 78, the distal covering portion 25 can effectively reduce wear of the drive shaft 20.

[0060] (5) In the medical device 10 of (4) above, the curved portion 78 may have a first curved portion 78a and a second curved portion 78b that are spaced apart in the longitudinal direction and curved in opposite directions to each other. This allows the drive shaft 20 of the medical device 10 to easily come into contact with the outer tube shaft 70, so that the wear of the drive shaft 20 can be effectively reduced by the tip covering portion 25.

[0061] (6) In the medical device 10 of (3) or (4) above, the tip covering part 25 may extend continuously into the inside of the drive shaft 20 from a position distal to the curved part 78 to a position proximal to the curved part 78. This makes it possible for the medical device 10 to prevent the tip covering part 25 from peeling off even if the drive shaft 20 comes into contact with the inner surface of the outer tube shaft 70 at the curved part 78.

[0062] (7) In any of the medical devices 10 described above in (2) to (6), the tip covering part 25 may extend into the inside of the wire to a depth of more than 0 μm and not more than 100 μm from an imaginary plane connecting the surfaces furthest from the axis of the wire. This allows the medical device 10 to ensure sufficient fixing strength of the tip covering part 25 to the drive shaft 20.

[0063] (8) In the medical device 10 of any of (1) to (7) above, the drive shaft 20 may have an additional coil 23 wound in a spiral shape on the outer circumferential surface, and the base end position of the distal covering part 25 may be on the distal side of the distal end position of the additional coil 23. This makes it possible to prevent the lumen of the medical device 10 from narrowing in the portion where the additional coil 23 is provided.

[0064] (9) In any of the medical devices 10 described above in (1) to (8), a protective tube 60 through which a guidewire is inserted may be disposed inside the drive shaft 20. This makes it possible to protect the guidewire from being damaged by the rotating drive shaft 20.

[0065] (10) In the medical device 10 of (9) above, the protective tube 60 may be arranged so as not to rotate together with the drive shaft 20. This makes it possible to prevent the guide wire from rotating together with the drive shaft 20 when the drive shaft 20 rotates.

[0066] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical concept of the present invention. The medical device 10 is not limited to devices that cut and remove objects in blood vessels, and the present invention can be applied to other types of devices that have a metal tube at the tip, such as an ultrasonic catheter. [Explanation of symbols]

[0067] 10 Medical Devices 20 Drive shaft 21 Wire rod 23 Additional coil 25 Tip coating 30 Shaft Aisle 40 50 Cutting part 60 Protection tube 70 Outer tube shaft 71 Outer tube body 73 Tip tube 73a Tip side rough surface 73b Proximal rough surface 73c middle part 74 Covering material 75 Proximal tube 76 Proximal covering material 77 Connecting material 78 Curved Section 78a First curved section 78b Second curved section 80 Bearings 90 Handle 91 Casing 92 Drive unit 110 Lumens Intake 111 Intake opening 112 Proximal opening

Claims

1. A medical device having a long drive shaft that rotates around a central axis along a long axis direction, and a long outer tube shaft that is disposed outside the drive shaft, A medical device in which the outer surface of the tip of the drive shaft is covered with a resin tip coating.

2. the drive shaft is a tube in which a plurality of wires are arranged and connected in a spiral shape around the axis, The medical device of claim 1 , wherein at least a portion of the tip coating extends into the drive shaft between the wires.

3. 3. The medical device of claim 2, wherein the tip coating has a proximal end and a distal end, the proximal end extending deeper into the drive shaft than the distal end.

4. The outer tube shaft has a curved portion at a tip portion, The medical device according to claim 3 , wherein the proximal end of the distal covering portion is located proximal to the curved portion.

5. The medical device according to claim 4 , wherein the curved portion has a first curved portion and a second curved portion that are spaced apart in the longitudinal direction and curved in opposite directions to each other.

6. The medical device according to claim 4 , wherein the distal covering portion extends continuously from a position distal to the curved portion to a position proximal to the curved portion inside the drive shaft.

7. The medical device according to any one of claims 2 to 6, wherein the tip coating portion extends into the interior to a depth of more than 0 μm and not more than 100 μm from an imaginary plane connecting the surfaces furthest from the axis of the wire.

8. the drive shaft has an additional coil wound helically around its outer periphery; The medical device according to any one of claims 1 to 6, wherein the proximal end position of the distal covering portion is on the distal side of the distal end position of the additional coil.

9. The medical device according to any one of claims 1 to 6, wherein a protective tube through which a guide wire is inserted is disposed inside the drive shaft.

10. The medical device of claim 9 , wherein the protective tube is arranged not to rotate with the drive shaft.

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