Medical device

Abstract

To provide a medical device capable of suppressing detachment of a conveyor coil fixed to a drive shaft from the drive shaft.SOLUTION: A medical device 10 for removing an object in a biological lumen, includes a rotatable drive shaft 20, a cutting part 80 rotatably driven by the drive shaft 20 to cut the object, an outer tube shaft 50 for rotatably housing the drive shaft 20, and a loosely-wound conveyor coil 30 arranged to wind around an outer periphery of the drive shaft 20, where the conveyor coil 30 is fixed to the drive shaft 20 only at a tip part of the conveyor coil 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a medical device for removing objects from a biological lumen. [Background technology]

[0002] Methods for treating stenosis caused by plaque or thrombus in blood vessels include expanding blood vessels with a balloon and placing a mesh or coil stent in the blood vessel to support the blood vessel. However, these methods are difficult to treat stenosis that has hardened due to calcification or that occurs at a branching point of blood vessels. As a device that can treat such cases, an atherectomy device has been proposed that cuts the lesion while sucking and removing the cut material (see, for example, Patent Document 1).

[0003] The atherectomy device has a drive shaft that rotates at high speed inside the outer tube. When a spiral transport coil is attached to the drive shaft, the transport coil rotates with the high speed rotation of the drive shaft, and the cut material can be transported outside the body. In other words, the transport coil that rotates together with the drive shaft can transport the cut material in the proximal direction based on the Archimedes pump principle. [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] A wide range of additional torque is applied to the drive shaft of the atherectomy device when cutting the lesion, when not cutting, and when the cutting part is bitten into the lesion. The drive shaft expands and contracts in its entire length like a spring depending on the load torque. The delivery coil needs to follow the expansion and contraction of the drive shaft, but cannot follow the drive shaft without mechanical load because it is directly subjected to friction with the drive shaft and the outer tube shaft that rotatably houses the delivery coil. For this reason, if the connection between the delivery coil and the drive shaft is weak, the delivery coil may come off the drive shaft.

[0006] In particular, when a load torque is applied to the transport coil inside a curved blood vessel in a living body, it is difficult for the transport coil to expand and contract uniformly as a whole, and non-uniform expansion and contraction occurs inside the outer tube. As a result, the fixed part of the transport coil to the drive shaft is constantly subjected to a mechanical load, which may eventually cause it to break down.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device that can prevent a conveying coil fixed to a drive shaft from detaching from the drive shaft. [Means for solving the problem]

[0008] The above object can be achieved by the invention described in (1) below. (1) A medical device according to the present invention is a medical device for removing an object from a biological lumen, comprising a rotatable drive shaft, a cutting section capable of cutting the object when rotated by the drive shaft, an outer tube shaft for rotatably housing the drive shaft, and a loosely wound transport coil arranged to wind around the outer periphery of the drive shaft, wherein the transport coil is fixed to the drive shaft only at its tip portion. Effect of the Invention

[0009] In the medical device described in (1) above, when the drive shaft expands and contracts in the axial direction, the portion of the transport coil that is closer to the base end than the tip portion fixed to the drive shaft can move in the axial direction relative to the drive shaft, thereby reducing the load on the fixed portion of the transport coil to the drive shaft. Therefore, the medical device can prevent the transport coil fixed to the drive shaft from coming off the drive shaft.

[0010] (2) In the medical device described in (1) above, the transport coil may contract and the drive shaft may extend during rotation. The transport coil contracts to prevent the fluid receiving force from the transport coil from generating a swirling flow, thereby improving transport efficiency. The drive shaft extends to prevent problems caused by the drive shaft becoming shorter.

[0011] (3) In the medical device according to (1) or (2), the transport coil may be fixed to the drive shaft only at the tip of the transport coil. This further reduces the load on the part where the transport coil is fixed to the drive shaft, and effectively prevents the transport coil from coming off the drive shaft. In addition, the flexibility of the drive shaft and the transport coil is improved, and the operability of the medical device inside a curved body is improved.

[0012] (4) In the medical device described in any one of (1) to (3) above, the transport coil may have a multi-thread coil made of a plurality of wires wound therein, and an integral part formed by melting the plurality of wires arranged in the circumferential direction to integrally form the entire circumferential direction, and the transport coil may be fixed to the integral part. If the portion of the drive shaft to which the transport coil is fixed is not an integral part but is one of the wires, the wire may break, but if the transport coil is fixed to the integral part of the drive shaft, damage to the drive shaft can be suppressed.

[0013] (5) In the medical device according to any one of (1) to (4) above, the coil base end located at the base end of the transport coil may be formed in a curved shape, thereby making it possible to suppress damage to the drive shaft or the outer tube shaft with which the coil base end of the transport coil comes into contact. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a plan view showing a medical device according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the tip of a medical device. [Diagram 3] FIG. 13 shows the vicinity of the distal end of the inner and outer layers of a medical device, with the drive shaft and delivery coil shown in plan view and the rest in cross-section. [Figure 4] This figure shows a cross-section of the outer layer shaft and a plan view of the drive shaft and conveying coil. (A) shows the state in which the drive shaft is rotating, (B) shows the state in which the spiral pitch of the conveying coil is reduced, and (C) shows the state in which the drive shaft is twisted due to a load torque acting on it. [Diagram 5] FIG. 1 is a schematic diagram showing a state in which a lesion is being removed by a medical device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the size and ratio of each member in the drawings may be exaggerated for convenience of explanation and may differ from the actual size and ratio. In addition, in this specification, the side of the medical device 10 that is inserted into the body is referred to as the "distal side" and the side that is operated is referred to as the "base side".

[0016] The medical device 10 according to this embodiment is inserted into blood vessels in acute lower limb ischemia or deep vein thrombosis and is used in a procedure for destroying and removing thrombi, plaque, atheroma, calcified lesions, etc. Note that the objects to be removed are not necessarily limited to thrombi, plaque, atheroma, and calcified lesions, and may be any object that may exist in a biological lumen.

[0017] As shown in Figures 1 and 2, the medical device 10 comprises a long drive shaft 20, a transport coil 30 for transporting an object, an outer tube shaft 50 for accommodating the drive shaft 20 and the transport coil 30, a cutting section 80 for cutting objects such as thrombi, a rotating shaft 70 connecting the cutting section 80 to the drive shaft 20, a tip bearing section 60 for rotatably supporting the rotating shaft 70, a guidewire lumen tube 40 disposed inside the drive shaft 20, and a handle 90.

[0018] As shown in Figures 2 and 3, the outer tube shaft 50 comprises an outer layer 51, an inner layer 52, a shaft tip portion 53, a first covering tube 54 in close contact with the outer peripheral surface of the outer layer 51, and a second covering tube 55 in close contact with the outer peripheral surface of the shaft tip portion 53.

[0019] The drive shaft 20 is a multi-layer coil in which coils are stacked in layers. The drive shaft 20 is flexible and has a property of being able to transmit a drive torque acting from the base end side to the tip side. The drive shaft 20 is rotatable inside the outer tube shaft 50. The drive shaft 20 includes an inner coil 21, an outer coil 22 surrounding the outside of the inner coil 21, and a tip protection tube 23 covering the outer circumferential surface of the tip portion of the outer coil 22. The drive shaft 20 may be a multi-layer coil having three or more layers.

[0020] The outer coil 22 is wound in a direction in which the spiral of the wire constituting the outer coil 22 tightens and reduces in diameter when the drive shaft 20 receives a driving torque from the base end side and rotates in a determined rotation direction (the rotation direction of the drive shaft 20 when the medical device 10 is used for cutting and transporting). That is, the wire of the outer coil 22 is formed so as to be wound in the opposite direction to the determined rotation direction as it moves toward the tip side when viewed from the base end side. The outer coil 22 has a characteristic of receiving a driving torque from the base end side while the drive shaft 20 rotates in the determined rotation direction and reducing in diameter, while extending along the axis of the outer coil 22. The outer coil 22 may be a single-strand coil in which one wire is wound, or a multi-strand coil in which multiple wires are wound side by side.

[0021] The inner coil 21 is wound in a direction in which the spiral of the wire constituting the inner coil 21 loosens and expands in diameter when the drive shaft 20 receives a driving torque from the base end side and rotates in a determined rotation direction. That is, the wire of the inner coil 21 is formed so as to be wound in a determined rotation direction toward the tip side as viewed from the base end side. The inner coil 21 has a characteristic of expanding in diameter when receiving a driving torque from the base end side while the drive shaft 20 rotates in a determined rotation direction, and contracting along the axis of the inner coil 21. The inner coil 21 may be a single-strand coil in which one wire is wound, or a multiple-strand coil in which multiple wires are wound side by side.

[0022] The outer coil 22 is disposed in close contact with the outer circumferential surface of the inner coil 21. Therefore, when the drive shaft 20 rotates in a predetermined rotation direction, the inner coil 21 expands in diameter while attempting to contract, and the outer coil 22 contracts in diameter while attempting to expand, thereby offsetting the radial and axial displacements of the outer coil 22 and the inner coil 21. Therefore, the multi-layer coil formed by the outer coil 22 and the inner coil 21 can reduce the radial and axial deformations when the drive shaft 20 rotates in a predetermined rotation direction. Note that the inner coil 21 has a larger coil radius than the outer coil 22, so the action of the outer coil 22 is stronger than the action of the inner coil 21. Therefore, when the drive shaft 20 rotates in a predetermined rotation direction, the drive shaft 20 contracts slightly in the radial direction and expands slightly in the axial direction.

[0023] As an example, the outer coil 22 is a multi-thread coil in which 16 wire rods are tightly wound in a spiral shape. The inner coil 21 is a multi-thread coil in which 8 wire rods are tightly wound in a spiral shape. The number of wire rods in the outer coil 22 and the inner coil 21 is not particularly limited. The cross-sectional shape of each of the wire rods in the outer coil 22 and the inner coil 21 is, for example, circular, but is not particularly limited and may be elliptical, rectangular, square, triangular, etc.

[0024] The drive shaft 20 may be a single-layer coil. In this case, if the wire of the single-layer coil is wound in the opposite direction to the determined rotational direction as it approaches the tip side, as viewed from the base end, the drive shaft 20 receives a driving torque from the base end and contracts in diameter while extending along the axis. If the wire of the single-layer coil is wound in the determined rotational direction as it approaches the tip side, as viewed from the base end, the drive shaft 20 receives a driving torque from the base end and contracts in diameter along the axis.

[0025] The drive shaft 20 has a ring-shaped integral part 24 formed integrally in the circumferential direction by melting and joining wires arranged in the circumferential direction of the outer coil 22 on the proximal side of the shaft tip part 53. In the integral part 24, it is preferable that not only the outer coil 22 but also at least the outer portion of the inner coil 21 is integrally formed, but this is not limited thereto. In order to reduce the flexibility of the drive shaft 20, it is preferable that the integral part 24 is not too long in the axial direction.

[0026] As shown in Figs. 3 and 4, the conveying coil 30 is arranged so as to be wound around the outer periphery of the drive shaft 20. The conveying coil 30 is partially in contact with the outer periphery of the drive shaft 20, but may be arranged with a gap. The conveying coil 30 is formed by loosely winding the wire constituting the conveying coil 30 so as to have a gap in the axial direction of the conveying coil 30. The conveying coil 30 has a fixed part 31 located at the tip of the conveying coil 30 and fixed to the drive shaft 20, and a non-fixed part 32 located on the base end side of the fixed part 31 and not fixed to the conveying coil 30. The coil base end 33 located at the base end of the conveying coil 30 is formed in a hemispherical shape. That is, the coil base end 33 is formed in a curved shape. The fixed part 31 is fixed to the integral part 24 of the drive shaft 20 by welding or the like. If the part of the drive shaft 20 to which the fixed part 31 is fixed is not the integral part 24 but any wire, the wire may melt too much by welding or the like and break, causing damage to the drive shaft 20. Furthermore, when a torque load is applied, if stress is concentrated on the drive coil 20, which is made up of multiple thin wires, problems such as breakage or deformation of the wires may occur. In contrast, if the fixed part 31 of the conveying shaft 30 is fixed to the integral part 24 of the drive shaft 20 by welding or the like, the multiple wires form an integrated part 24, which will not break, and damage to the drive shaft 20 can be suppressed.

[0027] The fixed portion 31 may be not only the tip of the conveying coil 30, but also at least a part of the tip portion of the conveying coil 30 (a portion within a predetermined range on the tip side).

[0028] The conveying coil 30 functions as an Archimedes screw (screw pump) when the drive shaft 20 rotates in a predetermined rotation direction, and conveys liquid or objects in the direction toward the base end. For this purpose, the conveying coil 30 is formed so as to be wound in the predetermined rotation direction as it moves toward the tip end side, as viewed from the base end side. The tip end of the conveying coil 30 is located on the base end side of the curved shaft tip portion 53 disposed at the tip end of the outer tube shaft 50. This can prevent the conveying coil 30 and the curved shaft tip portion 53 from being damaged by friction caused by the rotation of the drive shaft 20. The conveying coil 30 may be formed so as to be wound in the opposite direction to the predetermined rotation direction as it moves toward the tip end side, as viewed from the base end side. In this case, the conveying coil 30 functions as an Archimedes screw (screw pump) when the drive shaft 20 rotates in a predetermined rotation direction, and can convey liquid or objects in the direction toward the tip end.

[0029] Suitable materials for the drive shaft 20 and the conveying coil 30 include, for example, stainless steel, nitinol (NiTi), Ta, Ti, Pt, Au, W, polyolefins such as polyethylene and polypropylene, polyesters such as polyamide and polyethylene terephthalate, fluorine-based polymers such as ethylene-tetrafluoroethylene copolymer (ETFE), polyether ether ketone (PEEK), and polyimide.

[0030] 2 and 3, the tip protection tube 23 is a tubular body that covers the outer peripheral surface of the drive shaft 20 on the tip side of the conveying coil 30. The tip protection tube 23 is disposed inside the shaft tip portion 53 provided on the outer tube shaft 50. The tip protection tube 23 is formed of a heat-shrinkable tube that shrinks in diameter by heating, for example, to fit closely to the drive shaft 20. The tip protection tube 23 prevents the drive shaft 20 and the shaft tip portion 53 from coming into contact with each other and being damaged as the drive shaft 20 rotates.

[0031] The material of the heat shrink tube is not particularly limited, but may be, for example, polyolefin, polyamide, Pebax, polyurethane, or polyethylene terephthalate.

[0032] The guidewire lumen tube 40 is a tubular body disposed inside the drive shaft 20, as shown in Fig. 2. The guidewire lumen tube 40 is formed with a guidewire lumen 41 through which a guidewire passes. The guidewire passing through the guidewire lumen 41 is prevented from rubbing against the drive shaft 20. The distal end of the guidewire lumen tube 40 protrudes further distally than the drive shaft 20, and is disposed inside the rotating shaft 70 and the cutting section 80. The proximal end of the guidewire lumen tube 40 is connected to a handle 90.

[0033] As shown in Figs. 1 to 4, the outer tube shaft 50 is a long tube that houses the drive shaft 20. The outer tube shaft 50 can transmit the torque applied by the surgeon using the rotation operation part 91 fixed to the base end of the outer tube shaft 50 to the tip side. A first lumen 57 for feeding a liquid such as physiological saline to the tip side is formed between the outer layer 51 and the inner layer 52. At least one side hole 58 penetrating from the inner peripheral surface to the outer peripheral surface is formed at the tip of the outer layer 51. The outer tube shaft 50 can rotate to direct the cutting part 80 to the lesion. The outer tube shaft 50 has a base end opening 120 that opens inside the handle 90 at the base end.

[0034] The outer layer 51 is preferably flexible enough to bend in a living lumen and has high torque transmission properties. The material of the outer layer 51 may be, for example, a circular tube made of a metal material or a resin material having a certain degree of strength, with a spiral slit or groove formed by laser processing. The material of the outer layer 51 is not particularly limited, and may be, for example, a metal material such as stainless steel, nitinol (NiTi), Ta, Ti, Pt, Au, or W, or an engineering plastic such as ABS resin, polycarbonate (PC), polymethyl methacrylate (PMMA), polyacetal (POM), polyphenylsulfone (PPSU), polyethylene (PE), carbon fiber, or polyether ether ketone (PEEK).

[0035] The first covering tube 54 is a tubular body that is in close contact with the outer peripheral surface of the outer layer 51. The first covering tube 54 prevents liquid in the first lumen 57 from leaking through a gap in a spiral slit formed in the outer layer 51. The first covering tube 54 is formed of a heat-shrinkable tube that is reduced in diameter by heating and is in close contact with the outer layer 51, for example.

[0036] The inner layer 52 is disposed inside the outer layer 51 with a gap therebetween. The gap between the inner layer 52 and the outer layer 51 is a first lumen 57. A second lumen 59 is formed inside the inner layer 52 for discharging objects such as the cut thrombus toward the base end. The tip end of the inner layer 52 is fixed to the inner circumferential surface of the shaft tip end 53 with an adhesive or the like. The base end of the inner layer 52 is located inside the handle 90.

[0037] The resin material forming the inner layer 52 desirably has a certain degree of flexibility and low friction, and polyether ether ketone (PEEK), fluoropolymers such as PTFE·ETFE, polymethyl methacrylate (PMMA), polyethylene (PE), polyether block acid copolymer (PEBAX), polyamide, polyimide, and combinations thereof can be suitably used. The inner layer 52 may have braided reinforcing wires. The inner surface of the inner layer 52 is preferably formed of a resin material. This can reduce friction between the inner layer 52 and the conveying coil 30. The resin material forming the inner surface of the inner layer 52 can be polyimide, PTFE, polyamide, etc. This can improve the wear resistance of the inner layer 52 and the conveying coil 30 while improving the slipperiness.

[0038] As shown in Figs. 2 and 3, the shaft tip portion 53 is located at the tip portion of the outer tube shaft 50. The shaft tip portion 53 is bent at two bent portions 56 so that the axis of the base end portion of the shaft tip portion 53 is offset from the axis of the tip portion. The number of bent portions 56 may be one or more than three. By rotating the outer tube shaft 50, the shaft tip portion 53 can direct the cutting portion 80 toward the lesion and further strongly press the cutting portion 80 against the lesion. The material of the shaft tip portion 53 can be, for example, a material applicable to the outer layer 51 described above.

[0039] The second covering tube 55 is a tubular body that fits tightly against the outer circumferential surface of the shaft tip portion 53. The second covering tube 55 is formed of a heat-shrinkable tube that shrinks in diameter by heating, for example, to fit tightly against the shaft tip portion 53.

[0040] As shown in Fig. 2, the tip bearing 60 is fixed to the tip of the shaft tip 53 and is disposed further to the tip side than the shaft tip 53. The tip bearing 60 rotatably supports a rotating shaft 70 fixed to the tip of the outer tube shaft 50. The tip bearing 60 is fixed to the tip of the shaft tip 53. A tip opening 61 is formed on the tip side of the tip bearing 60 for transporting cut objects such as thrombus, blood, and liquid discharged from the side hole 58 and taking them into the second lumen 59. The tip of the tip bearing 60 is located on the base end side of the cutting portion 80.

[0041] The rotating shaft 70 is rotatably supported by the tip bearing portion 60 fixed to the tip portion of the outer tube shaft 50. The base end of the rotating shaft 70 is fixed to the tip portion of the drive shaft 20, and the tip portion of the rotating shaft 70 is fixed to the cutting portion 80. The rotating shaft 70 has at least one groove-like passage 71 formed therein, extending along the axis. The passage 71 allows the object cut by the cutting portion 80 to pass through the inside of the tip bearing portion 60 in the base end direction.

[0042] The cutting unit 80 is a member that cuts objects such as thrombus, plaque, and calcified lesions to reduce their size. Therefore, "cutting" means applying force to an object in contact with it to reduce the size of the object. The method of applying force in cutting and the shape and form of the object after cutting are not limited. The cutting unit 80 has the strength to cut the objects described above. The cutting unit 80 is fixed to the outer circumferential surface of the tip of the rotating shaft 70. The cutting unit 80 has many tiny abrasive grains on its surface. Alternatively, the cutting unit 80 may be equipped with a sharp blade.

[0043] The constituent material of the cutting part 80 preferably has a strength sufficient to cut a thrombus, and for example, stainless steel, Ta, Ti, Pt, Au, W, shape memory alloys, super steel alloys, ceramic materials, etc. The constituent material of the tip bearing part 60 and the rotating shaft 70 preferably has a certain degree of strength, and the above-mentioned materials applicable to the cutting part 80 can be used.

[0044] As shown in FIG. 1, the handle 90 includes a rotation operation unit 91, a casing 92, a drive unit 93, an intake port 95, and a liquid delivery port 96.

[0045] The casing 92 has a rotary operation part 91 rotatably connected to its tip, and has an intake space 121 communicating with the intake port 95 and a liquid delivery space 122 communicating with the liquid delivery port 96 formed therein. The base end opening 120 of the outer tube shaft 50 is rotatably disposed in the intake space 121.

[0046] The rotation operation unit 91 is a part that an operator operates with his / her fingers to apply torque to the outer tubular shaft 50. The rotation operation unit 91 is rotatably connected to the tip end of a casing 92. The rotation operation unit 91 is fixed to the outer circumferential surface of the base end of the outer tubular shaft 50.

[0047] The drive unit 93 is, for example, a hollow motor. The drive unit 93 rotates by a battery (not shown) or power supplied from an external source. The drive shaft 20 is fixed to a hollow drive rotor of the hollow motor. The rotation speed of the drive unit 93 is not particularly limited, but is, for example, 10,000 to 150,000 rpm, and preferably 20,000 to 120,000 rpm. The configuration of the drive unit 93 is not particularly limited. Since the drive unit 93 is a hollow motor, the guidewire lumen tube 40 and the guidewire can pass through the drive unit 93.

[0048] The intake port 95 transports objects, liquids, etc., inside the intake space 121 to the outside. An intake drive source such as a pump or a syringe can also be connected to the intake port 95. From the liquid delivery port 96, a fluid can be delivered to the first lumen 57 of the outer tube shaft 70 via the liquid delivery space 122.

[0049] Next, a method of using the medical device 10 according to the embodiment will be described. Here, as shown in FIG. 5, a case in which a calcified lesion S in a blood vessel is destroyed and transported will be described as an example.

[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 41 of the medical device 10. Thereafter, the surgeon moves the cutting portion 80 of the medical device 10 to the vicinity of the lesion S using the guidewire W as a guide.

[0051] Next, the surgeon operates the handle 90 to start the operation of the drive unit 93. This causes the drive shaft 20 connected to the drive unit 93, the rotating shaft 70 fixed to the drive shaft 20, and the cutting unit 80 to rotate. As a result, the surgeon can cut the lesion S with the cutting unit 80. In addition, when the drive shaft 20 rotates, as shown in Figs. 3 and 4(A), the conveying coil 30 fixed to the drive shaft 20 generates a force to convey the liquid or object in the second lumen 59 to the base end side. As a result, as shown in Fig. 2, the cut fragments are taken in and discharged from the tip opening 61 of the second lumen 59 of the outer tube shaft 50.

[0052] When the surgeon wants to change the position of the cutting portion 80 in the circumferential direction, the surgeon can operate the rotation operation unit 91 shown in FIG. 1. When the surgeon rotates the rotation operation unit 91, the outer tube shaft 50 fixed to the rotation operation unit 91 rotates. When the outer tube shaft 50 rotates, as shown in FIG. 5, the position and direction of the part on the distal side of the bent portion 56 of the outer tube shaft 50 changes, and the position and direction of the cutting portion 80 can be changed. Therefore, the cutting portion 80 can be cut while changing the position and direction by only operating the rotation operation unit 91 without rotating the entire handle 90, which is difficult to rotate greatly. Furthermore, the surgeon moves the entire handle 90 or the outer tube shaft 50 exposed outside the body, and moves the outer tube shaft 50 back and forth along the longitudinal direction of the blood vessel. This allows the cutting portion 80 to cut the lesion S along the longitudinal direction of the blood vessel.

[0053] When a fluid is sent from the fluid sending port 96 through the fluid sending space 122 to the first lumen 57 of the outer tubular shaft 70, the fluid is discharged into the first lumen 57 as shown in Fig. 3. The physiological saline solution sent to the first lumen 57 moves toward the tip and is released into the blood vessel from the side hole 58 formed at the tip of the outer layer 51.

[0054] A portion of the saline solution discharged into the blood vessel is taken into the second lumen 59 from the distal opening 61 of the outer tubular shaft 50 together with the blood and the cut object, as shown in Figures 2 and 5. The object and liquid that have entered the second lumen 59 move in the proximal direction through the second lumen 59. The object and liquid that have entered the second lumen 59 are transported in the proximal direction by the transport coil 30, and are discharged to the outside via the intake port 95 of the handle 90, as shown in Figure 1.

[0055] The driving shaft 20 and the conveying coil 30 are subjected to various loads during rotation. As shown in FIG. 4(A), the driving shaft 20 in this embodiment contracts in the radial direction and expands in the axial direction when rotating in a specified rotation direction. In contrast, the conveying coil 30 is fixed to the driving shaft 20 only at the fixed part 31 on the tip side, and has a non-fixed part 32 at the base end that is not fixed to the driving shaft. Therefore, the conveying coil 30 is less likely to receive a force that tends to expand in the axial direction due to the radial contraction of the driving shaft 20. On the other hand, the conveying coil 30 receives a driving torque at the fixed part 31 on the tip side from the driving shaft 20 rotating in the specified rotation direction. As a result, the conveying coil 30 tries to expand along the axial center while the spiral of the wire constituting the conveying coil 30 tightens and shrinks in diameter, independent of the expansion of the driving shaft 20. Furthermore, the conveying coil 30 applies a conveying force in the proximal direction to the liquid or object in the second lumen 59, and receives a reaction force in the distal direction from the liquid or object, so that, for example, as shown in FIG. 4B, the pitch width of the spiral of the conveying coil 30 becomes shorter. When the pitch width of the spiral becomes shorter, the generation of a swirling flow SW (swirl) of the fluid receiving the force from the rotating conveying coil 30 is reduced, and conveying efficiency is improved. As described above, the conveying coil 30 receives various forces depending on the situation and expands or contracts along the axis. Moreover, since the conveying coil 30 is wound sparsely rather than densely, it is easy to expand and contract along the axis. In this way, the conveying coil 30 expands or contracts in the axial direction independently of the drive shaft 20 at the proximal side of the fixed part 31, and therefore moves relative to the drive shaft 20 surrounded by the non-fixed part 32 of the conveying coil 30.

[0056] The drive shaft 20 receives a driving torque from the base end side, and the drive shaft 20 contracts in the radial direction and expands in the axial direction. At this time, the drive shaft 20 receives a load torque from, for example, the cutting portion 80 on the tip side of the drive shaft 20, and is twisted, and as shown in FIG. 4(C), it curves in a meandering manner within the outer tube shaft 50 and tends to become shorter in the axial direction than the outer tube shaft 50. On the other hand, the conveying coil 30 contacts the inner circumferential surface of the outer tube shaft 50, and tends to remain in that position due to friction with the outer tube shaft 50. Therefore, the drive shaft 20, which is surrounded by the non-fixed portion 32 of the conveying coil 30 on the base end side of the fixed portion 31, moves relatively toward the tip side of the non-fixed portion 32.

[0057] As described above, even if the drive shaft 20 and the conveying coil 30 are deformed by various loads, the non-fixed part 32 of the conveying coil 30 can change its position in the axial direction relative to the drive shaft 20. This reduces the load on the fixed part 31 of the conveying coil 30 relative to the drive shaft 20, and prevents the conveying coil 30 from detaching from the drive shaft 20. In addition, for example, it is possible to prevent the wire of the conveying coil 30 from riding up so as to overlap, or the winding direction of the conveying coil 30 from becoming reversed.

[0058] After the cutting and transportation of the lesion S is completed, the surgeon operates the handle 90. This stops the rotation of the drive shaft 20 and the fluid supply. After this, the surgeon removes the medical device 10 from the blood vessel, completing the treatment.

[0059] As described above, the medical device 10 according to the present embodiment is a medical device 10 for removing an object in a living body lumen, and includes a rotatable drive shaft 20, a cutting section 80 that is driven to rotate by the drive shaft 20 and can cut an object, an outer tube shaft 50 that rotatably houses the drive shaft 20, and a loosely wound conveying coil 30 arranged to wind around the outer periphery of the drive shaft 20, and the conveying coil 30 is fixed to the drive shaft 20 only at the tip portion of the conveying coil 30. As a result, when the drive shaft 20 expands and contracts in the axial direction, the medical device 10 can reduce the load on the fixed portion 31 of the conveying coil 30 relative to the drive shaft 20 because the part of the conveying coil 30 on the base end side of the tip portion fixed to the drive shaft 20 can move in the axial direction relative to the drive shaft 20. Therefore, the medical device 10 can suppress the conveying coil 30 fixed to the drive shaft 20 from coming off from the drive shaft 20.

[0060] During rotation, the conveying coil 30 contracts and the drive shaft 20 expands. The contraction of the conveying coil 30 suppresses the generation of a swirling flow SW in the fluid receiving force from the conveying coil 30, improving conveying efficiency. The expansion of the drive shaft 20 suppresses the occurrence of problems caused by the shortening of the drive shaft 20 (for example, the drive shaft 20 getting caught inside the outer tube shaft 50).

[0061] The transport coil 30 is fixed to the drive shaft 20 only at the tip of the transport coil 30. This further reduces the load on the fixed portion 31 of the transport coil 30 relative to the drive shaft 20, and effectively prevents the transport coil 30 from becoming detached from the drive shaft 20. In addition, the flexibility of the drive shaft 20 and the transport coil 30 is improved, improving the operability of the medical device 10 inside a curved body.

[0062] The transport coil 30 has a multi-strand coil made of multiple wire rods wound around it, and has an integral part 24 formed integrally in the entire circumferential direction by melting multiple wire rods arranged in the circumferential direction, and the transport coil 30 is fixed to the integral part 24. If the part of the drive shaft 20 to which the transport coil 30 is fixed is not the integral part 24 but any of the wire rods, there is a possibility that the wire rods will break. However, if the transport coil 30 is fixed to the integral part 24 of the drive shaft 20, damage to the drive shaft 20 can be suppressed.

[0063] The coil base end 33 located at the base end of the transport coil 30 is formed in a curved shape. This makes it possible to prevent damage to the drive shaft 20 and the outer tube shaft 50 with which the coil base end 33 of the transport coil 30 comes into contact.

[0064] 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. For example, the biological lumen into which the medical device 10 is inserted is not limited to a blood vessel, and may be, for example, a vascular tract, a ureter, a bile duct, an oviduct, a hepatic duct, etc. The present invention can also be used in surgical instruments such as a morcellator. [Explanation of symbols]

[0065] 10 Medical Devices 20 Drive shaft 24 Integral part 30 Carrying coil 31 Fixed part 32 Non-fixed part 33 Coil base end 50 Outer tube shaft 80 Cutting section

Claims

1. 1. A medical device for removing an object within a biological lumen, comprising: a drive shaft that is rotatable; and a cutting unit that is rotationally driven by a drive shaft and is capable of cutting the object; an outer tube shaft that rotatably houses the drive shaft; a loosely wound conveying coil arranged to wind around the outer periphery of the drive shaft; A medical device, wherein the transport coil is fixed to the drive shaft only at a tip portion of the transport coil.

2. 10. The medical device of claim 1, wherein during rotation, the delivery coil contracts axially and the drive shaft expands axially.

3. 3. The medical device of claim 1, wherein the transport coil is fixed to the drive shaft only at a tip of the transport coil.

4. the conveying coil has a multi-strand coil formed by winding a plurality of wire rods, and has an integral portion formed integrally in the entire circumferential direction by melting the plurality of wire rods arranged in the circumferential direction, The medical device of claim 1 or 2, wherein the transport coil is fixed to the integral part.

5. The medical device according to claim 1 or 2, wherein a coil base end located at a base end of the transport coil is formed in a curved shape.

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