Medical device

An elongated medical device that is insertable into a living body lumen, the medical device comprising:

• a drive shaft having a distal end and a proximal end, and being rotatable in a predetermined direction of rotation in response to a driving force from a proximal side of the drive shaft to transmit a rotational force in a distal direction;
• a cutting portion configured to cut an object in the living body lumen when the cutting portion is rotated while the cutting portion is positioned in the living body lumen to produce cut objects, the cutting portion being operatively connected to the drive shaft so that rotation of the drive shaft causes rotation of the cutting portion, the cutting portion having a most distal end and a most proximal end;
• the drive shaft comprising:
• an inner coil comprised of a plurality of wires wound side-by-side in a circumferential direction of the drive shaft;
• an outer coil comprised of a plurality of wires wound side-by-side in the circumferential direction of the drive shaft, the outer coil surrounding the inner coil;
• the plurality of wires of the inner coil being wound in the predetermined direction of rotation toward the distal direction as viewed from the proximal side;
• the plurality of wires of the outer coil being wound in a direction opposite to the predetermined direction of rotation in the distal direction as viewed from the proximal side;
• a total number of the plurality of wires constituting the inner coil being smaller than a total number of the plurality of wires constituting the outer coil;
• the drive shaft including a conveyance coil comprised of at least one wire spirally wound in a longitudinal direction of the drive shaft, the conveyance coil forming an outermost layer or an innermost layer of the drive shaft;
• a guide wire lumen tube disposed inside the drive shaft, the guide wire lumen tube extending from a most distal end of the guide wire lumen tube to a most proximal end of the guide wire lumen tube, the most distal end of the guide wire lumen tube being an open end and the most proximal end of the guide wire lumen tube being an open end, the guide wire lumen tube having a guide wire lumen configured to receive a guide wire, the guide wire lumen extending from the most distal end of the guide wire lumen tube to the most proximal end of the guide wire lumen tube;
• the guide wire lumen tube having an outer surface and the inner coil having an inner surface;
• a space between the outer surface of the guide wire lumen tube and the inner surface of the inner coil;
• the most distal end of the guide wire lumen tube being positioned on a distal side of the distal end of the drive shaft;
• and
• the most distal end of the guide wire lumen tube being positioned between the most distal end of the cutting portion and the most proximal end of the cutting portion.

A medical device to cut an object in a living body lumen, the medical device comprising:

• a rotatable drive shaft that is rotatable in a first direction of rotation in response to a driving force applied to the drive shaft;
• a cutting portion operatively connected to the drive shaft so that rotation of the drive shaft in the first direction of rotation results in rotation of the cutting portion, the cutting portion having an outer surface configured to cut the object in the living body lumen when the cutting portion is rotated while the cutting portion is positioned in the living body lumen;
• the drive shaft comprising an outer coil and an inner coil, the outer coil surrounding the inner coil so that the outer coil covers an outer surface of the inner coil;
• the inner coil being comprised of a total number N1 of wires that extend helically in side-by-side relation to one another, the total number N1 of wires extending helically in the first direction of rotation in the distal direction as viewed from the proximal side, the total number N1 being a number greater than one;
• the outer coil being comprised of a total number N2 of wires that extend helically in side-by-side relation to one another, the total number N2 of wires extending helically in a direction opposite the first direction of rotation in the distal direction as viewed from the proximal side, the total number N2 being a number greater than one;
• N1/N2 being less than 1;
• an outer tubular shaft in which is positioned the drive shaft, the outer tubular shaft including an inner layer and an outer layer positioned so that an inner peripheral surface of the outer layer faces an outer peripheral surface of the inner layer, the inner layer and the outer layer being spaced apart from one another so that a first lumen exists between the inner peripheral surface of the outer layer and the outer peripheral surface of the inner layer, the first lumen being fluidly connectable to a liquid feeding source so that during operation of the medical device liquid from the liquid feeding source is fed to the first lumen;
• the outer layer including at least one through hole passing through the outer layer and fluidly communicating the first lumen with outside the medical device so that during operation of the medical device while the cutting portion is positioned in the living body lumen and liquid is being fed from the liquid feeding source to the first lumen, a first portion of the liquid in the first lumen passes through the at least one through hole in the outer layer and enters the living body lumen;
• the inner layer having an inner peripheral surface that faces an outer peripheral surface of the drive shaft so that a second lumen exists between the inner peripheral surface of the inner layer and the outer peripheral surface of the drive shaft, the inner layer including at least one through hole passing through the inner layer and fluidly communicating the first and second lumens so that during operation of the medical device while the cutting portion is positioned in the living body lumen and liquid is being fed from the liquid feeding source to the first lumen, a second portion of the liquid in the first lumen passes through the at least one through hole in the inner layer and enters the second lumen;
• and
• the second lumen being in fluid communication with a distal end opening located on a distal side of the at least one through hole in the inner layer and being fluidly connectable to a waste holder that is on the proximal side of the at least one through hole in the inner layer so that during operation of the medical device while the cutting portion is positioned in the living body lumen, the cut objects, blood and at least some of the first portion of the liquid that entered the living body lumen by way of the at least one through hole in the outer layer pass through the distal end opening, enter the second lumen and are conveyed toward the waste holder together with at least some of the second portion of the liquid that entered the second lumen by way of the at least one through hole in the inner layer.