The cutting portion 24 is a member that is configured to cut the object such as a thrombus. The cutting portion 24 is fixed to an outer peripheral surface of the distal portion of the drive shaft 20. The cutting portion 24 has a large number of minute abrasive grains on its outer surface. Alternatively, the cutting portion 24 may include a sharp blade.

The rotating shaft portion 33 is rotatably supported by the distal bearing portion 43 provided on the outer tube shaft 22. A proximal portion of the rotating shaft portion 33 is fixed to the coil member 30, and a distal portion of the rotating shaft portion 33 is fixed to the cutting portion 24. The rotating shaft portion 33 has at least one groove-shaped passage 33a extending along the axis (i.e., along the longitudinal axis or axial extent pf the rotating shaft portion 33). The passage 33a allows the object(s) cut by the cutting portion 24 to pass through an inside of (i.e., radially inwardly of) the distal bearing portion 43 in the proximal direction.

A constituent material for the cutting portion 24 preferably has sufficient strength to cut a thrombus, and examples of such material include stainless steel, Ta, Ti, Pt, Au, W, a shape memory alloy, and a cemented carbide.

The handle portion 28 includes a casing 50, a drive unit 51, a liquid delivering unit 52, a switch 53, a suction tube 102, a first liquid delivering tube 100, a second liquid delivering tube 101, a discharge tube 103, and an electric cable 104. The handle portion 28 further includes the operation portion 54, the housing 60, and a shaft support 70.

The casing 50 forms an outline of the handle portion 28. The casing 50 accommodates the drive unit 51, the housing 60, the shaft support 70, the first liquid delivering tube 100, the second liquid delivering tube 101, a part of the discharge tube 103, and a part of the electric cable 104. A passage hole 56 through which the drive shaft 20, the outer tube shaft 22, and the guide wire lumen tube 26 pass is formed in a distal portion of the casing 50.

The drive unit 51 is, for example, a hollow motor. The drive unit 51 includes a hollow power shaft 51a that generates a driving force by electric power supplied from outside via the electric cable 104. The power shaft 51a passes through the drive unit 51 and rotates while being supported by a bearing. The power shaft 51a accommodates the drive shaft 20 therein. An inner peripheral surface of the power shaft 51a is in slidable contact with an outer peripheral surface of the drive shaft 20. The drive shaft 20 substantially penetrates the power shaft 51a, and the proximal portion of the drive shaft 20 is fixed to a proximal portion of the power shaft 51a by welding, adhesion, or the like. A rotation speed of the power shaft 51a is not particularly limited, and may be, for example, 5,000 rpm to 200,000 rpm. The drive unit 51 is connected to a control apparatus, and can be controlled from an inside or an outside of the handle portion 28.

The electric cable 104 can be connected to an external power supply or the control apparatus. The switch 53 is a portion operated by the operator to drive and stop the drive unit 51. The switch 53 is located on an outer surface of the casing 50. When a battery is provided in the handle portion 28, an electric cable is located in the handle portion 28 and connected to the battery. When the electric cable 104 is connected to the external power supply, the control apparatus can be provided in the handle portion 28 to perform signal processing on an operation input of the switch 53 and control the drive unit 51 and the liquid delivering unit 52.

The operation portion 54 is a portion that is operated by the operator with the fingers to apply a rotational torque to the outer tube shaft 22. The operation portion 54 is fixed to the operation fixing portion 83 of the seal holding portion 80 to which the outer tube shaft 22 is fixed. The operation portion 54 includes an operation dial 54a and a fixing recess 54b. The operation dial 54a is a substantially disk-shaped portion operated by the operator with the fingers. An outer peripheral surface of the operation dial 54a has high frictional resistance so as to be easily operated. The operation fixing portion 83 of the seal holding portion 80 is fitted into and fixed to the fixing recess 54b. When the operator rotates the operation portion 54, the outer tube shaft 22 fixed to the operation portion 54 rotates with respect to the drive shaft 20, the guide wire lumen tube 26, and the casing 50. At this time, the first elastic bodies 90 and the second elastic bodies 91 held by the seal holding portion 80 to which the operation portion 54 is fixed slide on the outer peripheral surface of the seal holding portion 80 while receiving frictional resistance. The frictional resistance of the first elastic bodies 90 and the second elastic bodies 91 with respect to the seal holding portion 80 is large enough to hold an orientation of a rotation direction of the outer tube shaft 22. Therefore, when the operator releases the fingers after rotating the operation dial 54a, a rotated position is held by the frictional resistance of the first elastic bodies 90 and the second elastic bodies 91 with respect to the seal holding portion 80. The first elastic bodies 90 and the second elastic bodies 91 may be held on the outer peripheral surface of the seal holding portion 80 and slide on an inner peripheral surface of the housing 60.

The housing 60 includes a discharge port 61 through which the liquid or the object is discharged, and a first liquid delivering port 62 and a second liquid delivering port 63 through which the liquid is delivered. The housing 60 further includes a first liquid delivering lumen 64 with which the first liquid delivering port 62 communicates, a second liquid delivering lumen 65 with which the second liquid delivering port 63 communicates, and a discharge lumen 66 with which the discharge port 61 communicates.

The first liquid delivering lumen 64 has a predetermined inner diameter and is disposed in a distal portion of the housing 60. The first liquid delivering lumen 64 rotatably accommodates the seal holding portion 80. The first elastic bodies 90 and the second elastic bodies 91 held by the seal holding portion 80 are in slidable contact with an inner peripheral surface of the first liquid delivering lumen 64. The first liquid delivering port 62 is formed at a position communicating with the supply port 82 of the seal holding portion 80. The first liquid delivering port 62 is located on the proximal side with respect to the first elastic bodies 90, and is located on the distal side with respect to the second elastic bodies 91. The first liquid delivering port 62 is connected to the first liquid delivering tube 100 and can receive the liquid from the first liquid delivering tube 100. The liquid delivered from the first liquid delivering port 62 can flow from the supply port 82 into the liquid delivering lumen 45 formed between the torque shaft 48 and the inner layer 41. At this time, the first elastic bodies 90 prevent the liquid in the first liquid delivering lumen 64 from leaking to an outside of the housing 60. In addition, the second elastic bodies 91 prevent the liquid in the first liquid delivering lumen 62 from leaking to the discharge lumen 66. In addition, the second sealing portion 41b that fixes the inner layer 41 and the seal holding portion 80 prevents the liquid flowing into the liquid delivering lumen 45 from leaking to the discharge lumen 66. The first elastic bodies 90 and the second elastic bodies 91 may be held by a groove portion formed on the inner peripheral surface of the first liquid delivering lumen 64 instead of the seal holding portion 80.

The second liquid delivering lumen 65 has a predetermined inner diameter and is disposed in a proximal portion of the housing 60. The housing 60 includes an accommodation portion 67 that accommodates the shaft support 70 that seals the second liquid delivering lumen 65. The accommodation portion 67 includes a first accommodation portion 67a that accommodates the proximal portion of the drive shaft 20, and a second accommodation portion 67b that has an inner diameter larger than that of the first accommodation portion 67a and accommodates the shaft support 70. A third elastic body 75 held by the shaft support 70 is in contact with an inner peripheral surface of the second liquid delivering lumen 65. A position of the second liquid delivering lumen 65 which is in contact with the third elastic body 75 is on the proximal side with respect to the second liquid delivering port 63. That is, the position at which the third elastic body 75 contacts the inner surface of the second accommodation portion 67b is proximal of the second liquid delivering port 63. A distal side of the second liquid delivering lumen 65 communicates with the discharge lumen 66. The second liquid delivering port 63 is connected to the second liquid delivering tube 101 and can receive the liquid from the second liquid delivering tube 101. The liquid delivered from the second liquid delivering port 63 can flow into the discharge lumen 66 communicating with the second liquid delivering lumen 65. At this time, the third elastic body 75 prevents the liquid in the second liquid delivering lumen 65 from leaking to the outside of the housing 60.

The discharge lumen 66 is disposed between the first liquid delivering lumen 64 and the second liquid delivering lumen 65. The discharge lumen 66 communicates with the second liquid delivering lumen 65. An inner diameter of the discharge lumen 66 is smaller than the inner diameter of the first liquid delivering lumen 64 and the inner diameter of the second liquid delivering lumen 65. The discharge port 61 is connected to the discharge tube 103. A proximal end of the outer tube shaft 22 is open in the discharge lumen 66. The drive shaft 20 protruding from the proximal end of the outer tube shaft 22 in the proximal direction passes through the discharge lumen 66 and further extends in the proximal direction. Therefore, the discharge lumen 47 formed between the outer tube shaft 22 and the drive shaft 20 communicates with the discharge lumen 66. The discharge lumen 66 can receive the liquid or the object from the discharge lumen 47, and the liquid or the object can be discharged from the discharge port 61 to the discharge tube 103.

The shaft support 70 is a member that is inserted into or positioned in the second accommodation portion 67b of the accommodation portion 67 from a proximal side of the housing 60, holds a portion of the drive shaft 20 on the distal side with respect to the drive unit 51, that is, the proximal portion of the drive shaft 20, and partially closes the second liquid delivering lumen 65. The shaft support 70 includes a support lumen 71 penetrating or extending along the axis (central axis or longitudinal axis) of the drive shaft 20, a third recess 72 formed in an outer peripheral surface thereof, and a lid portion 73 having an outer diameter larger than the inner diameter of the second accommodation portion 67b and facing a proximal surface of the housing 60. The drive shaft 20 and the guide wire lumen tube 26 pass through the support lumen 71.

The third recess 72 accommodates the third elastic body 75 such as an O-ring. The third elastic body 75 is in contact with the outer peripheral surface of the shaft support 70 and an inner peripheral surface of the second accommodation portion 67b, and maintains liquid-tightness between the shaft support 70 and the second liquid delivering lumen 65. The third recess 72 has a width larger than that of the third elastic body 75.

A distal surface of the lid portion 73 faces a proximal surface (proximal end surface) of the second accommodation portion 67b. A proximal surface of the lid portion 73 faces stopper portions 68 protruding from the housing 60. Movement of the shaft support 70 in an axial direction is restricted by the stopper portions 68, and detachment of the shaft support 70 from the housing 60 is prevented.

As shown in FIG. 6, a gap P1 is provided between the shaft support 70 and the housing 60. An outer diameter of the shaft support 70 is smaller than the inner diameter of the second accommodation portion 67b. Therefore, the gap P1 is formed between the outer peripheral surface of the shaft support 70 and the inner peripheral surface of the second accommodation portion 67b of the housing 60. FIG. 6 shows gaps in an exaggerated manner. The gap P1 is in a range of 25 μm to 125 μm. However, a size of the gap P1 may be in a range other than this.

A gap P2 is provided between the lid portion 73 of the shaft support 70 and the proximal surface of the second accommodation portion 67b facing the lid portion 73. In addition, a gap P3 is provided between the proximal surface of the lid portion 73 and the stopper portions 68. The gaps P1, P2, and P3 can cause the shaft support 70 to turn with respect to the housing 60 so as to tilt the axial direction. In addition, the gap P1 can cause the shaft support 70 to move in parallel with respect to the housing 60 while maintaining the axial direction thereof constant. That is, the shaft support 70 is movable in the accommodation portion 67.

Examples of constituent materials for the first elastic bodies 90, the second elastic bodies 91, and the third elastic body 75 include silicone rubber, ethylene propylene rubber, nitrile rubber, chloroprene rubber, isoprene rubber, butyl rubber, styrene butadiene rubber, natural rubber such as polyurethane, synthetic rubber, and a silicone resin. As the constituent materials for the first elastic bodies 90, the second elastic bodies 91, and the third elastic body 75, a resin material such as PTFE, FEP, or nylon may be used. As shown in FIG. 6, cross-sectional shapes of the first elastic bodies 90, the second elastic bodies 91, and the third elastic body 75 are not limited to a circular or elliptical shape, and may be a rectangular shape.

Examples of constituent materials for the housing 60, the seal holding portion 80, the lid portion 73, and the operation portion 54 include ultra high molecular weight polyethylene, polyester, polyamides, fluorine-based resins such as polytetrafluoroethylene, an ABS resin, polyacetal (POM), polycarbonate (PC), polypropylene (PP), polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), and a combination of two or more thereof (polymer alloys, polymer blends, laminates, or the like).

The liquid delivering unit 52 is a pump that delivers the liquid to the housing 60 via the first liquid delivering tube 100 and the second liquid delivering tube 101. The liquid delivering unit 52 is connected to the suction tube 102 that receives a supply of the liquid such as physiological saline from a liquid delivering source outside the casing 60, and can suction the liquid from the suction tube 102. The liquid delivering unit 52 is connected to the first liquid delivering tube 100 and the second liquid delivering tube 101, and can discharge the suctioned liquid to the first liquid delivering tube 100 and the second liquid delivering tube 101. The external liquid delivering source is, for example, a physiological saline bag, but is not limited thereto. The liquid delivering unit 52 may be provided outside the handle portion 28 instead of being provided in the handle portion 28. The liquid delivering unit 52 is not limited to a pump as long as a liquid delivering pressure can be generated, and may be, for example, a syringe, a bag suspended from a drip tower, or a pressurized bag.

The discharge tube 103 is a tube that discharges the liquid or the object to the outside of the casing 50. The discharge tube 103 is connected to, for example, a waste liquid bag capable of accommodating the liquid or the object. The discharge tube 103 may be connected to an aspiration source that can perform active aspiration, such as a pump or a syringe.

The proximal portion of the drive shaft 20 is connected to the power shaft 51a via a proximal shaft 38 provided on an outer peripheral side of the drive shaft 20. The drive shaft 20 is welded or bonded at a proximal portion of the proximal shaft 38, and the proximal shaft 38 is bonded or welded to the power shaft 51a, whereby the drive shaft 20 is fixed. When the shaft support 70 and the drive shaft 20 are directly connected to each other, a large amount of leakage occurs due to the rotation of the drive shaft 20 formed with the coil member 30, but the leakage can be reduced by interposing the proximal shaft 38 between the shaft support 70 and the drive shaft 20.

Next, a method of using the medical device 10 according to the present embodiment will be described. Here, a case where a calcified lesion area in a blood vessel is destroyed (e.g., broken-up) and aspirated will be described as an example.

First, the operator inserts the guide wire W into the blood vessel and causes the guide wire W to reach the vicinity of a lesion area S. Next, the operator inserts a proximal end of the guide wire W into the guide wire lumen 27 of the medical device 10. Thereafter, as shown in FIG. 7(a), the cutting portion 24 of the medical device 10 is moved to the vicinity of the lesion area S using the guide wire W as a guide.

Next, the operator operates the switch 53 to start operations of the drive unit 51 and the liquid delivering unit 52. Accordingly, the power shaft 51a of the drive unit 51 rotates, and the drive shaft 20 fixed to the power shaft 51a and the cutting portion 24 fixed to the drive shaft 20 rotate. Accordingly, the operator can cut the lesion area S by the cutting portion 24. When the power shaft 51a rotates, the conveying coil 32 disposed on the outer peripheral surface of the drive shaft 20 generates a force for conveying the liquid or the object in the discharge lumen 47 to the proximal side and in the proximal direction. An aspiration force is applied to the distal opening portion 43a of the outer tube shaft 22.

When the operator wants to change a position of the cutting portion 24 in a circumferential direction, the operator can operate the operation portion 54. When the operator rotates the operation dial 54a, the outer tube shaft 22 fixed to the operation portion 54 rotates. The seal holding portion 80 of the outer tube shaft 22 to which the operation portion 54 is fixed rotates inside the first liquid delivering lumen 64 of the housing 60. At this time, the seal holding portion 80 slides on inner peripheral surfaces of the first elastic bodies 90 and the second elastic bodies 91. When the outer tube shaft 22 rotates, a direction of the distal portion of the shaping shaft 42 provided at the distal portion of the outer tube shaft 22 changes, and the position of the cutting portion 24 can be changed as shown in FIG. 7(b). Therefore, cutting can be performed while changing the direction of the cutting portion 24 without rotating the entire handle portion 28 that is difficult to rotate greatly. Further, the operator moves the entire handle portion 28 or the outer tube shaft 22 exposed to the outside of the body in the axial direction to reciprocate the outer tube shaft 22 along a longitudinal direction of the blood vessel. Accordingly, as shown in FIG. 7(c), the lesion area S can be cut along the longitudinal direction of the blood vessel by the cutting portion 24.

When the lesion area S is cut by the cutting portion 24, a central axis of the drive shaft 20 may swing or tilt. As shown in FIG. 8, a case where a central axis 20b of the drive shaft 20 swings so as to be tilted by an angle A from an original central axis 20a will be described as an example. In this case, the shaft support 70 can tilt with respect to the housing 60 in accordance with the tilt of the drive shaft 20. This is because gaps are provided between the outer peripheral surface of the shaft support 70 and the inner peripheral surface of the second accommodation portion 67b of the accommodation portion 67, between the lid portion 73 of the shaft support 70 and the proximal surface of the second accommodation portion 67b of the accommodation portion 67, and between a proximal surface (proximal end surface) of the shaft support 70 and the stopper portions 68, respectively. Since the shaft support 70 is supported on the housing 60 by the third elastic body 75, the shaft support 70 can turn around the third elastic body 75 with respect to the housing 60. In this way, by tilting the shaft support 70 following the tilt of the drive shaft 20, friction between the drive shaft 20 and the shaft support 70 can be reduced, and a rotational torque loss of the drive shaft 20 can be reduced.

The central axis of the drive shaft 20 may swing or shift so as to move in parallel from the original central axis 20a. As shown in FIG. 9, when a central axis 20c moves in parallel by a distance B from the original central axis 20a (i.e. the central axis 20c is not coaxial with the original central axis 20a), the shaft support 70 can move in parallel with respect to the housing 60 in accordance with the movement of the drive shaft 20. Accordingly, the rotational torque loss of the drive shaft 20 can be reduced.

Since the third recess 72 has a width larger than that of the third elastic body 75, the shaft support 70 supported on the housing 60 by the third elastic body 75 is easily turned with respect to the housing 60. Therefore, the shaft support 70 can easily follow the swing of the drive shaft 20.

When the operation of the liquid delivering unit 52 is started, physiological saline is suctioned into the liquid delivering unit 52 from the suction tube 102 and discharged to the first liquid delivering tube 100 and the second liquid delivering tube 101. The physiological saline discharged to the first liquid delivering tube 100 flows into the first liquid delivering lumen 64 of the housing 60 from the first liquid delivering port 62. The physiological saline that flows into the first liquid delivering lumen 64 from the first liquid delivering port 62 flows into the liquid delivering lumen 45 formed between the outer layer 40 and the inner layer 41 from the supply port 82 of the seal holding portion 80. At this time, the first elastic bodies 90 prevent the liquid in the first liquid delivering lumen 64 from leaking to the outside of the housing 60. In addition, the second elastic bodies 91 prevent the liquid in the second liquid delivering lumen 65 from leaking to the discharge lumen 66. In addition, the second sealing portion 41b that fixes the inner layer 41 and the seal holding portion 80 prevents the liquid flowing into the liquid delivering lumen 45 from leaking to the discharge lumen 66. Therefore, the physiological saline that flows into the first liquid delivering lumen 64 from the first liquid delivering port 62 is effectively guided to the liquid delivering lumen 45 while maintaining a high liquid delivering pressure.

The physiological saline discharged to the second liquid delivering tube 101 flows into the second liquid delivering lumen 65 of the housing 60 from the second liquid delivering port 63. The third elastic body 75 prevents the liquid in the second liquid delivering lumen 65 from leaking to the outside of the housing 60. In addition, the physiological saline supplied from the second liquid delivering tube 101 to the second liquid delivering lumen 65 flows into the discharge lumen 66 on the distal side.

The physiological saline that entered the liquid delivering lumen 45 moves in a distal direction. The physiological saline that moved in the liquid delivering lumen 45 in the distal direction is discharged into the blood vessel from the liquid delivering opening portion 46 formed in the distal portion of the outer layer 40. A part of the physiological saline discharged into the blood vessel is, together with blood and the cut object, aspirated into the discharge lumen 47 from the distal opening portion 43a of the outer tube shaft 22. The object and the liquid that enter the discharge lumen 47 move in the discharge lumen 47 toward the proximal direction. The object and the blood to be aspirated into the discharge lumen 47 are diluted with the physiological saline. Therefore, a discharge amount is increased by decreasing the viscosity of the discharged material, and formation of a thrombus in the discharge lumen 47 is prevented. Therefore, aspiration performance can be improved while preventing a decrease of the aspiration force or a damage of the medical device 10 due to the formation of the thrombus in the discharge lumen 47. In addition, the thrombus formed in the medical device 10 is prevented from flowing into the body lumen. By mixing an anticoagulant such as heparin into a physiological salt solution in advance, an effect of preventing the thrombus formation can be improved.

When the liquid or the object that enters the discharge lumen 47 moves in the discharge lumen 47 toward the proximal direction, the liquid or the object reaches the discharge lumen 66 of the housing 60 from the proximal opening portion 48a on the inner layer 41. When the liquid or the object reaches the discharge lumen 66, the liquid or the object is discharged from the discharge port 61 to the external waste liquid bag via the discharge tube 103.

The physiological saline flows into the discharge lumen 66 from the second liquid delivering lumen 65 on the proximal side. Accordingly, the liquid or the object flowing from the discharge lumen 47 into the discharge lumen 66 is diluted by the physiological saline. Therefore, the discharge amount is increased by decreasing the viscosity of the discharged material, and the formation of thrombi in the discharge lumen 47, the discharge lumen 66, and the discharge tube 103 is prevented. Therefore, the aspiration performance is improved while preventing the decrease of the aspiration force or the damage of the medical device 10 due to the formation of the thrombi in the discharge lumen 47, the discharge lumen 66, and the discharge tube 103. Even in this case, by mixing the anticoagulant such as heparin into the physiological salt solution in advance, the effect of preventing the thrombus formation can be improved.

In addition, the second liquid delivering port 63 is disposed adjacent to the shaft support 70 located in the second liquid delivering lumen 65. Therefore, the shaft support 70 can be cooled and lubricated by the physiological salt solution from the second liquid delivering port 63.

After the cutting and the aspiration of the lesion area S are completed, the operator presses the switch 53. Accordingly, rotation of the drive shaft 20 is stopped, and the liquid delivery performed by the liquid delivering unit 52 is stopped. Thereafter, the operator removes the medical device 10 from the blood vessel and completes the procedure.

A modification of the medical device 10 will be described. As shown in FIG. 10, the medical device 10 according to a first modification includes, at a proximal portion of the support lumen 71, a proximal large-diameter portion 76 having an inner diameter larger than an inner diameter of the support lumen 71. The inner diameter of the proximal large-diameter portion 76 is constant from the proximal end of the support lumen 71 toward the distal side. Since the proximal large-diameter portion (first lumen portion) 76 has the inner diameter larger than that of the support lumen (second lumen portion)