Positioning method of medical device and medical device

Abstract

To provide a positioning method of a medical device capable of positioning a cutting part in an appropriate direction, and the medical device.SOLUTION: A positioning method of a medical device 10 for cutting an object inside a blood vessel, including a rotatable drive shaft 20, a cutting part 80 arranged at a tip side of the drive shaft 20, a drive part 93 for rotating the drive shaft 20, and an outer tube shaft 50 for rotatably housing the drive shaft 20, the positioning method includes: a step S1 of rotating the cutting part 80 at a preset first rotation speed after bringing the cutting part 80 close to a lesion S in the blood vessel; a step S2 of determining whether or not a stop condition for preliminary operation at the first rotation speed is satisfied; and a step S4 of rotating the cutting part 80 at a preset second rotation speed of 10,000 rpm or more and 150,000 rpm or less after it is determined that the stop condition of the preliminary operation is satisfied.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for positioning a medical device for cutting an object in a biological lumen and to a medical device. [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 the branching part of blood vessels. As a device that can treat such cases, an atherectomy device that cuts and removes the lesion has been proposed (see, for example, Patent Document 1).

[0003] An atherectomy device has a cutting part that rotates at high speed at the tip of a drive shaft that can rotate inside an outer tubular shaft, and removes thrombus, plaque, etc. from within blood vessels by shearing or crushing them. In particular, an atherectomy device with a shaped tip of the outer tubular shaft can adjust the direction of the tip of the outer tubular shaft, making it possible to selectively treat plaque, etc. that is unevenly present on the inner wall of a blood vessel. [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] The intravascular structure is highly diverse, and is often tortuous and has numerous irregularities. Under such conditions, after the direction of the outer tube shaft of the atherectomy device is determined, twists accumulate in the outer tube shaft, and during treatment, the direction of the outer tube shaft may be significantly shifted due to vibrations caused by the high-speed rotation of the drive shaft or the force that moves the outer tube shaft forward and backward. If this occurs, not only will the area that should be treated be unable to be treated, but there is also the possibility of damaging the blood vessel wall in areas that should not be treated.

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a medical device and a positioning method for a medical device that can position a cutting portion in an appropriate direction. [Means for solving the problem]

[0007] The above object can be achieved by the invention described in (1) below. (1) A positioning method for a medical device according to the present invention is a positioning method for a medical device for cutting an object inside a blood vessel, the medical device having a rotatable drive shaft, a cutting section arranged on the tip side of the drive shaft, a drive section for rotating the drive shaft, and an outer tube shaft for rotatably housing the drive shaft, the method comprising the steps of: rotating the cutting section at a predetermined first rotation speed after bringing the cutting section close to a lesion within the blood vessel; determining whether or not a pre-operation stop condition at the first rotation speed is satisfied; and rotating the cutting section at a predetermined second rotation speed of 10,000 rpm or more and 150,000 rpm or less after determining that the pre-operation stop condition is satisfied. Effect of the Invention

[0008] The method for positioning a medical device described in (1) above can eliminate twisting of the drive shaft and the outer tube shaft by pre-operation, so that the cutting part can be positioned in an appropriate direction before cutting.

[0009] (2) The method for positioning a medical device described in (1) above may include a step of reducing or stopping the rotation of the cutting unit after determining that the pre-operation stop condition is satisfied and before rotating the cutting unit at the second rotation speed, thereby making it possible to check whether or not the twisting of the drive shaft and the outer tube shaft has been eliminated by the pre-operation before the main operation for cutting.

[0010] (3) In the method for positioning a medical device according to (1) or (2) above, the first rotation speed may be 400 rpm or more and 10,000 rpm or less. This allows the pre-operation to be performed at a low speed, making it difficult for cutting by the cutting part to occur during the pre-operation, thereby improving safety.

[0011] (4) In the method for positioning a medical device described in (1) or (2) above, the first rotation speed may be equal to or greater than 10,000 rpm and equal to or less than 60,000 rpm. This makes the first rotation speed approximately equal to the second rotation speed, making it easy to adjust the rotation speed.

[0012] (5) In the method for positioning a medical device according to any one of (1) to (4) above, the pre-operation stop condition may be a time lapse of 0.01 seconds or more. This makes it possible to easily set the pre-operation stop condition so as to eliminate twisting of the drive shaft and the outer tube shaft.

[0013] (6) In the method for positioning a medical device according to any one of (1) to (4) above, the pre-operation stop condition may be a rotation number of the cutting part of 5 or more. This makes it possible to easily set the pre-operation stop condition so as to eliminate twisting of the drive shaft and the outer tube shaft.

[0014] (7) In the method for positioning a medical device according to any one of (1) to (6) above, in the step of rotating the cutting part at the first rotation speed, the cutting part may be rotated at the first rotation speed after the cutting part is directed toward the lesion in a blood vessel. Since twisting of the drive shaft and the outer tube shaft is eliminated after the cutting part is directed toward the lesion in a blood vessel, it is easy to recognize the occurrence of elimination of twisting.

[0015] (8) In the method for positioning a medical device according to any one of (1) to (6) above, in the step of rotating the cutting unit at the first rotation speed, the cutting unit may be rotated at the first rotation speed while pointing the cutting unit toward a lesion within a blood vessel. Since twisting of the drive shaft and the outer tube shaft is eliminated while the cutting unit is pointed toward the lesion within a blood vessel, it is easy to appropriately adjust the position and direction of the cutting unit 80 that have changed after the twisting is eliminated.

[0016] (9) A medical device according to the present invention is a medical device for cutting an object inside a blood vessel, the medical device having a rotatable drive shaft, a cutting section arranged on the tip side of the drive shaft, a drive section for rotating the drive shaft, an outer tube shaft for rotatably housing the drive shaft, and a control section for controlling the driving of the drive section, wherein the control section controls the drive section to rotate the cutting section at a predetermined first rotation speed, determines whether a stop condition for pre-operation at the first rotation speed is satisfied, and after determining that the stop condition for pre-operation is satisfied, controls the drive section to rotate the cutting section at a predetermined second rotation speed of 10,000 rpm or more and 150,000 rpm or less.

[0017] The medical device described in (9) above can eliminate twisting of the drive shaft and the outer tube shaft by pre-operation, so that the cutting part can be positioned in an appropriate direction before cutting is performed.

[0018] (10) In the medical device described in (9) above, the first rotation speed may be 400 rpm or more and 10,000 rpm or less. This allows the preliminary operation to be performed at a low speed, making it difficult for cutting by the cutting part to occur during the preliminary operation, thereby improving safety.

[0019] (11) In the medical device described in (9) above, the first rotation speed may be equal to or greater than 10,000 rpm and equal to or less than 60,000 rpm. This makes the first rotation speed approximately equal to the second rotation speed, making it easy to adjust the rotation speed.

[0020] (12) In the medical device according to any one of (9) to (11) above, the pre-operation stop condition may be a time lapse of 0.01 to 10 seconds, which makes it possible to easily set the pre-operation stop condition so as to eliminate twisting of the drive shaft and the outer tube shaft.

[0021] (13) In the medical device according to any one of (9) to (11) above, the pre-operation stop condition may be a rotation number of the cutting part of 5 or more rotations. This makes it possible to easily set the pre-operation stop condition so as to eliminate twisting of the drive shaft and the outer tube shaft.

[0022] (14) In the medical device described in any one of (9) to (11) above, a condition for stopping the main rotation at the second rotation speed may be a time period longer than a time period for the preliminary rotation. This ensures a sufficient main operation for cutting, allowing appropriate cutting to be performed. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a plan view of a medical device. [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] FIG. 1 is a block diagram of a medical device. [Diagram 5] FIG. 1 is a schematic diagram showing a state in which a lesion is being removed by a medical device. [Figure 6] 4 is a flowchart showing a control flow in a control unit. [Figure 7] 13 is a plan view showing a modified example of an action instruction portion provided on a handle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] 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".

[0025] 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.

[0026] As shown in Figures 1 to 4, 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, a handle 90, a control section 120 for controlling the operation of the medical device 10, and a rotation detection section 130.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] As shown in Figs. 3 and 4, the transport coil 30 is arranged so as to be wound around the outer periphery of the drive shaft 20. The transport coil 30 is in partial contact with the outer periphery of the drive shaft 20, but may be arranged with a gap. The transport coil 30 is formed by loosely winding the wire constituting the transport coil 30 so as to have a gap in the axial direction of the transport coil 30. The transport coil 30 is fixed to the drive shaft 20 at its tip.

[0036] 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 of the base end. For this reason, the conveying coil 30 is formed so as to be wound in a predetermined rotation direction as it moves toward the tip end side when viewed from the base end side.

[0037] 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.

[0038] 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.

[0039] The material of the heat shrink tube is not particularly limited, but may be, for example, polyolefin, polyamide, Pebax, polyurethane, or polyethylene terephthalate.

[0040] 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.

[0041] As shown in Figs. 1 to 4, the outer tube shaft 50 is a long tubular body 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 50A at the base end that opens inside the handle 90.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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, a liquid delivery port 96, and an operation instruction unit 97.

[0053] The casing 92 has a rotary operation part 91 rotatably connected to its tip, and is formed therein with an intake space 101 communicating with an intake port 95 and a liquid delivery space 102 communicating with a liquid delivery port 96. In the intake space 101, the base end opening 50A of the outer tube shaft 50 is rotatably disposed.

[0054] 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.

[0055] 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.

[0056] The intake port 95 transports objects, liquids, etc., inside the intake space 101 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 50 via the liquid delivery space 102.

[0057] The action instruction unit 97 is a part where the surgeon operates to start and stop the drive of the drive unit 93. The action instruction unit 97 is located on the outer surface of the casing 92. The action instruction unit 97 has, for example, a push button switch. The action instruction unit 97 has, for example, an action start button 97A that instructs the start of an action, and an action stop button 97B that instructs the stop of an action. Note that the button that instructs the start of an action and the button that instructs the stop of an action may be the same button.

[0058] The control unit 120 includes a memory circuit and an arithmetic circuit. The memory circuit stores programs and various parameters. The arithmetic circuit is, for example, a CPU (Central Processing Unit), and can read the programs and various parameters from the memory circuit and perform arithmetic processing. The control unit 120 is, for example, a computer, a microcontroller, a microprocessor, etc.

[0059] 4, the control unit 120 is instructed to start and stop operation by the operation instructing unit 97, and controls the operation of the driving unit 93. In addition, the control unit 120 obtains information regarding the number of rotations of the driving unit 93 from the rotation detecting unit .

[0060] The rotation detection unit 130 detects the rotation speed of the drive unit 93, the drive shaft 20, or the cutting unit 80. The rotation detection unit 130 may be included in the configuration of the control unit 120. The control unit 120 monitors the current value applied to the hollow motor of the drive unit 93 and can identify the rotation speed from the current value. The configuration of the rotation detection unit 130 is not particularly limited, and may be, for example, an optical or magnetic tachometer. Alternatively, when the motor of the drive unit 93 is a brushless motor, the motor itself has a function of detecting the rotation speed (function as a Hall magnetic sensor), and therefore the motor of the drive unit 93 forms the rotation detection unit 130.

[0061] Next, the operation of the medical device 10 will be described with reference to the flowchart shown in Fig. 6. Here, as an example, a case will be described in which a calcified lesion S in a blood vessel is destroyed and transported, as shown in Fig. 5.

[0062] First, the surgeon inserts the guidewire W into a 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 brings the cutting portion 80 of the medical device 10 close to the lesion S using the guidewire W as a guide.

[0063] Next, the surgeon starts fluid delivery through the fluid delivery port 96, and operates the handle 90 to direct the cutting unit 80 toward the lesion S, or while directing the cutting unit 80 toward the lesion S, operates the operation instruction unit 97 to start the operation of the drive unit 93 (step S1). Note that "the cutting unit 80 directs toward the lesion S" means that the lesion S is located on the tip side of the cutting unit 80, and the cutting unit 80 moves straight toward the tip side along the central axis of rotation of the cutting unit 80 to come into contact with the lesion S.

[0064] When the operation instruction unit 97 is operated, the control unit 120 controls the drive unit 93 to rotate the cutting unit 80 at a preset first rotation speed (step S1). Note that the preliminary operation at the first rotation speed is intended to eliminate twisting of the drive shaft 20 and the outer tube shaft 50, and cutting of the diseased area S by the cutting unit 80 is not performed. The first rotation speed is a low rotation speed of 400 rpm to 10,000 rpm, and is 5000 rpm as an example. Note that the first rotation speed may be higher. The first rotation speed may be a high rotation speed of 10,000 rpm to 60,000 rpm. In other words, the first rotation speed may be approximately the same as a second rotation speed described later.

[0065] Incidentally, the drive shaft 20 and the outer tube shaft 50 of the medical device 10 inserted into a meandering blood vessel may be twisted and strained. The twist in the drive shaft 20 increases when the friction between the drive shaft 20 and the outer tube shaft 50 is high, and the drive shaft 20 is significantly twisted inside the outer tube shaft 50 like a spring. Therefore, when the twist in the drive shaft 20 is released during a procedure, the direction in which the cutting portion 80 faces may change to an unintended direction.

[0066] Furthermore, the twisting of the outer tube shaft 50 becomes large when the friction between the outer circumferential surface of the outer tube shaft 50 and the inner wall of the blood vessel is high, and the outer tube shaft 50 is significantly twisted inside the blood vessel like a spring. Therefore, if the twisting of the outer tube shaft 50 is released during the procedure, there is a possibility that the direction of the cutting part 80 will change to an unintended direction.

[0067] In contrast, when the drive shaft 20 and the cutting unit 80 rotate at the first rotation speed, which is a preliminary operation that does not involve cutting, the contact between the inner circumferential surface of the outer tube shaft 50 and the outer circumferential surface of the drive shaft 20 due to static friction is eliminated, and the torsion accumulated in the drive shaft 20 and the outer tube shaft 50 is eliminated. Furthermore, the outer tube shaft 50 vibrates due to the preliminary operation, and the contact between the outer circumferential surface of the outer tube shaft 50 and the inner wall of the blood vessel due to static friction is eliminated, and the torsion accumulated in the outer tube shaft 50 is eliminated. Therefore, at the time of the actual operation at the second rotation speed that involves cutting, the torsion has already been eliminated, and the desired position of the lesion S can be cut while appropriately adjusting the direction of the cutting unit 80 to the intended direction by the rotation operation unit 91.

[0068] The control unit 120 continues the operation at the first rotation speed until a preset stop condition is satisfied. The control unit 120 judges whether the stop condition is satisfied (step S2), and when it judges that the stop condition is satisfied, reduces the rotation speed once (step S3). In step S3 of temporarily reducing the rotation speed, the rotation speed may be completely stopped, or may be reduced to a rotation speed lower than the first rotation speed without stopping. Alternatively, step S3 of temporarily reducing the rotation speed may not be provided. In other words, immediately after the preliminary operation at the first rotation speed, the main operation at high speed rotation may be started without reducing the rotation speed.

[0069] The stop condition of the preliminary operation is elapsed time or rotation speed. When the stop condition of the preliminary operation is elapsed time, the control unit 120 determines that the stop condition of the preliminary operation is satisfied when the elapsed time from the start of the operation at the first rotation speed reaches a preset threshold. The threshold of the elapsed time is preferably 0.01 to 10 seconds.

[0070] When the stop condition of the preliminary operation is the number of rotations, the control unit 120 calculates the number of rotations after the operation at the first rotation speed is started based on the signal obtained from the rotation detection unit 130. The control unit 120 determines that the stop condition of the preliminary operation is satisfied when the calculated number of rotations reaches a preset threshold value. The threshold value of the number of rotations is preferably 5 to 100 rotations.

[0071] After step S3 of temporarily reducing the rotation speed (or after step S2 of determining whether or not the preliminary operation stop condition is satisfied), the control unit 120 controls the drive unit 93 to rotate the cutting unit 80 at a preset second rotation speed (step S4). The second rotation speed is a high rotation speed suitable for cutting by the cutting unit 80, and is preferably 10,000 rpm to 150,000 rpm. If the first rotation speed is a low speed that is not suitable for cutting, the second rotation speed is faster than the first rotation speed. If the first rotation speed is a high speed that is suitable for cutting, the second rotation speed may be approximately the same as the first rotation speed.

[0072] When the drive unit 93 rotates, the cutting unit 80 rotates together with the drive shaft 20, enabling the cutting unit 80 to cut the lesion S. Furthermore, when the drive shaft 20 rotates, as shown in Fig. 3, the transport coil 30 fixed to the drive shaft 20 generates a force that transports liquid or objects in the second lumen 59 toward the base end side. This causes the cut fragments to be taken in and discharged from the distal end opening 61 of the second lumen 59 of the outer tube shaft 50, as shown in Fig. 2.

[0073] When the surgeon wants to change the position of the cutting part 80 in the circumferential direction, the surgeon can operate the rotation operation part 91 shown in FIG. 1. When the surgeon rotates the rotation operation part 91, the outer tube shaft 50 fixed to the rotation operation part 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 part 56 of the outer tube shaft 50 change, and the position and the direction of the cutting part 80 can be changed. Therefore, the position and the direction of the cutting part 80 can be adjusted while cutting by only operating the rotation operation part 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 part 80 to cut the lesion part S along the longitudinal direction of the blood vessel.

[0074] When a fluid is sent from the fluid sending port 96 through the fluid sending space 102 to the first lumen 57 of the outer tubular shaft 50, 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 distal end and is released into the blood vessel from the side hole 58 formed at the distal end of the outer layer 51.

[0075] A portion of the physiological 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 into the external waste fluid bag 100 via the intake port 95 of the handle 90, as shown in Figure 1.

[0076] After the cutting and transportation of the lesion S is completed, the surgeon operates the operation stop button 97B of the operation instruction unit 97. When the control unit 120 receives a signal from the operation instruction unit 97 instructing the operation to be stopped (step S5), it stops the drive unit 93 (step S6). This stops the rotation of the drive shaft 20. Thereafter, the surgeon removes the medical device 10 from the blood vessel, completing the treatment.

[0077] As described above, the medical device 10 in this embodiment is a medical device 10 for cutting an object inside a blood vessel, the medical device 10 having a rotatable drive shaft 20, a rotatable drive shaft 20, a cutting unit 80 arranged on the tip side of the drive shaft 20, a drive unit 93 for rotating the drive shaft 20, an outer tube shaft 50 for rotatably housing the drive shaft 20, and a control unit 120 for controlling the driving of the drive unit 93, in which the control unit 120 controls the drive unit 93 to rotate the cutting unit 80 at a predetermined first rotation speed (step S1), determines whether the stop condition of pre-operation at the first rotation speed is satisfied by the control unit 120 (step S2), and after determining that the stop condition of pre-operation is satisfied, controls the drive unit 93 to rotate the cutting unit 80 at a predetermined second rotation speed of 10,000 rpm or more and 150,000 rpm or less (step S4). This allows the medical device 10 to eliminate twisting of the drive shaft 20 and the outer tube shaft 50 through pre-operation, so that the cutting portion 80 can be positioned in an appropriate direction before cutting is performed.

[0078] The first rotation speed may be equal to or greater than 400 rpm and equal to or less than 10,000 rpm. This allows the pre-operation to be performed at a low speed, making it difficult for cutting by the cutting unit 80 to occur during the pre-operation, thereby improving safety.

[0079] The first rotation speed may be equal to or greater than 10,000 rpm and equal to or less than 60,000 rpm, so that the first rotation speed is approximately equal to the second rotation speed, making it easy to adjust the rotation speed.

[0080] The condition for stopping the preliminary operation may be a time lapse of 0.01 seconds or more and 10 seconds or less. This makes it possible to easily set the condition for stopping the preliminary operation so that the twisting of the drive shaft 20 and the outer tube shaft 50 can be eliminated.

[0081] The pre-operation stop condition may be 5 or more rotations of the cutting unit 80. This makes it possible to easily set the pre-operation stop condition so that twisting of the drive shaft 20 and the outer tube shaft 50 can be eliminated.

[0082] The stop condition of the main rotation at the second rotation speed may be a time lapse longer than the time of the preliminary rotation. The stop condition of the main rotation at the second rotation speed is, for example, a time lapse of 10 to 60 seconds, preferably 30 seconds. This ensures a sufficient main operation for cutting, and allows appropriate cutting. When the main rotation at the second rotation speed satisfies the time lapse of the stop condition, the control unit 120 controls the drive unit 93 to stop it. Next, when a predetermined rest time has elapsed, the control unit 120 can start the main rotation at the second rotation speed again. Then, the control unit 120 can repeat steps including the main rotation at the second rotation speed, the stop when the stop condition is satisfied, and the resumption of the main operation when the rest time has elapsed. The surgeon can stop this repeated operation by manually operating the handle 90 and pressing the operation stop button 97B of the operation instruction unit 97.

[0083] In the above-mentioned medical device 10, the control unit 120 judges whether the stop condition of the preliminary operation at the first rotation speed is satisfied and starts the main operation at the second rotation speed, but the surgeon may do so. For this purpose, as in the modified example shown in FIG. 7, the operation instruction unit 97 may have a first operation start button 97C for instructing the start of rotation of the cutting unit 80 at the first rotation speed, a second operation start button 97D for instructing the start of rotation of the cutting unit 80 at the second rotation speed, and an operation stop button 97B for instructing the stop of the operation. When starting the preliminary operation at the first rotation speed, the surgeon can press the first operation start button 97C (step S1). In addition, when the surgeon judges that the stop condition of the preliminary operation is satisfied (step S2), the surgeon can press the operation stop button 97B to reduce or stop the rotation of the preliminary operation at the first rotation speed (step S3). The stop condition of the preliminary operation may be determined based on the elapsed time or the number of rotations, but may be different, and may be determined when the surgeon detects the elimination of the twist of the drive shaft 20 or the outer tube shaft 50, for example, by a cine image. In addition, the surgeon can press the second operation start button 97D when starting the main operation at the second rotation speed. The surgeon may press the second operation start button 97D without pressing the operation stop button 97B while the cutting unit 80 is rotating at the first rotation speed. As a result, the control unit 120 reduces, stops, or maintains the rotation speed of the cutting unit 80, and then increases it to the second rotation speed (step S4). The surgeon can press the operation stop button 97B to stop the main operation at the second rotation speed. As a result, the control unit 120 receives a stop instruction due to the pressing of the operation stop button 97B (step S5), and stops the drive unit 93 (step S6).

[0084] As described above, the positioning method of the medical device 10 in this embodiment is a positioning method of the medical device 10 for cutting an object in a blood vessel, which has a rotatable drive shaft 20, a cutting unit 80 arranged on the distal end side of the drive shaft 20, a drive unit 93 for rotating the drive shaft 20, and an outer tube shaft 50 for rotatably housing the drive shaft 20, and includes the steps of: rotating the cutting unit 80 at a first rotation speed set in advance after the cutting unit 80 approaches a lesion S in the blood vessel; determining whether or not the stop condition of the pre-operation at the first rotation speed is satisfied; and rotating the cutting unit 80 at a second rotation speed set in advance of 10,000 rpm or more and 150,000 rpm or less after determining that the stop condition of the pre-operation is satisfied. As a result, the positioning method of the medical device 10 can eliminate twisting of the drive shaft 20 and the outer tube shaft 50 by the pre-operation, so that the cutting unit 80 can be positioned in an appropriate direction before cutting.

[0085] This positioning method may include step S3 of slowing down or stopping the rotation of the cutting unit 80 after it is determined that the stop condition of the preliminary operation is satisfied and before rotating the cutting unit 80 at the second rotation speed. This makes it possible to check whether the twisting of the drive shaft 20 and the outer tube shaft 50 has been eliminated by the preliminary operation before the main operation for cutting.

[0086] In the present positioning method, the first rotation speed may be equal to or greater than 400 rpm and equal to or less than 10,000 rpm, which can make it difficult for cutting by the cutting unit 80 to occur in the preliminary operation, thereby improving safety.

[0087] In the present positioning method, the first rotation speed may be equal to or greater than 10,000 rpm and equal to or less than 60,000 rpm, so that the first rotation speed is approximately the same as the second rotation speed, making it easy to adjust the rotation speeds.

[0088] In the present positioning method, the condition for stopping the preliminary operation may be the lapse of a time period of 0.01 seconds or more. This makes it possible to easily set the condition for stopping the preliminary operation so as to eliminate the twisting of the drive shaft 20 and the outer tube shaft 50.

[0089] In this positioning method, the pre-operation stop condition may be a rotation number of the cutting unit 80 of 5 or more. This makes it possible to easily set the pre-operation stop condition so as to eliminate twisting of the drive shaft 20 and the outer tube shaft 50.

[0090] In this positioning method, in step S1 of rotating the cutting unit 80 at a first rotation speed, the cutting unit 80 may be rotated at the first rotation speed after the cutting unit 80 is directed toward the lesion S inside the blood vessel. Since the twisting of the drive shaft 20 and the outer tube shaft 50 is eliminated after the cutting unit 80 is directed toward the lesion S inside the blood vessel, it is easy to recognize the occurrence of the elimination of the twisting.

[0091] In this positioning method, in step S1 of rotating the cutting unit 80 at a first rotation speed, the cutting unit 80 may be rotated at the first rotation speed while pointing the cutting unit 80 toward the lesion S inside the blood vessel. Since twisting of the drive shaft 20 and the outer tube shaft 50 is eliminated while the cutting unit 80 is pointed toward the lesion S inside the blood vessel, it is easy to appropriately adjust the position and direction of the cutting unit 80 that have changed after the twisting is eliminated.

[0092] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical concept of the present invention. For example, the body 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, a fallopian tube, a hepatic duct, or the like. [Explanation of symbols]

[0093] 10 Medical Devices 20 Drive shaft 50 Outer tube shaft 80 Cutting section 93 Drive unit 97 Operation instruction section 120 Control section

Claims

1. A method for positioning a medical device for cutting an object in a blood vessel, the medical device having a rotatable drive shaft, a cutting section disposed on a distal end side of the drive shaft, a drive section for rotating the drive shaft, and an outer tube shaft for rotatably housing the drive shaft, comprising: a step of rotating the cutting unit at a preset first rotation speed after the cutting unit approaches a lesion within a blood vessel; determining whether a stop condition for preliminary operation at the first rotation speed is satisfied; A method for positioning a medical device, comprising: a step of rotating the cutting portion at a second rotational speed that is preset to be equal to or greater than 10,000 rpm and equal to or less than 150,000 rpm after determining that the pre-operation stop condition is satisfied.

2. The method for positioning a medical device according to claim 1, further comprising a step of reducing or stopping rotation of the cutting unit after determining that the pre-operation stop condition is satisfied and before rotating the cutting unit at the second rotation speed.

3. 3. The method of claim 1, wherein the first rotational speed is greater than or equal to 400 rpm and less than or equal to 10,000 rpm.

4. 3. The method of claim 1, wherein the first rotational speed is greater than or equal to 10,000 rpm and less than or equal to 60,000 rpm.

5. 3. The method for positioning a medical device according to claim 1, wherein the condition for stopping the preliminary operation is the lapse of a time period of 0.01 seconds or more.

6. The method for positioning a medical device according to claim , wherein the condition for stopping the preliminary operation is that the number of rotations of the cutting part is 5 or more.

7. 2. The method for positioning a medical device according to claim 1, wherein in the step of rotating the cutting portion at the first rotational speed, the cutting portion is rotated at the first rotational speed after the cutting portion is directed toward a lesion within a blood vessel.

8. 2. The method for positioning a medical device according to claim 1, wherein in the step of rotating the cutting portion at the first rotational speed, the cutting portion is rotated at the first rotational speed while being directed toward a lesion within a blood vessel.

9. A medical device for cutting an object in a blood vessel, comprising: a rotatable drive shaft; a cutting unit disposed on a distal end side of the drive shaft; a drive unit for rotating the drive shaft; an outer tube shaft for rotatably housing the drive shaft; and a control unit for controlling the drive of the drive unit, The control unit controls the drive unit to rotate the cutting unit at a preset first rotation speed, determining whether a stop condition for preliminary operation at the first rotation speed is satisfied; A medical device characterized in that after it is determined that the pre-operation stop condition is satisfied, the drive unit is controlled to rotate the cutting unit at a preset second rotation speed of 10,000 rpm or more and 150,000 rpm or less.

10. 10. The medical device of claim 9, wherein the first rotational speed is greater than or equal to 400 rpm and less than or equal to 10,000 rpm.

11. 10. The medical device of claim 9, wherein the first rotational speed is greater than or equal to 10,000 rpm and less than or equal to 60,000 rpm.

12. The medical device according to any one of claims 9 to 11, characterized in that the condition for stopping the preliminary operation is the lapse of a time period of 0.01 seconds or more and 10 seconds or less.

13. The medical device according to any one of claims 9 to 11, characterized in that the pre-operation stop condition is a rotation speed of the cutting part of 5 rotations or more.

14. The medical device according to any one of claims 9 to 11, characterized in that a condition for stopping the main rotation at the second rotation speed is the lapse of a time longer than a time of the preliminary rotation.

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