Abstract: A dilator includes: a hollow shaft having a tapered portion whose outer diameter of the distal end is smaller than the outer diameter of the proximal end; a distal tip, whose proximal end is located at the distal end of the tapered portion, and which is provided to extend toward the distal end direction; and a spirally-arranged protruding portion provided on at least the outer peripheral surface of the tapered portion. The spirally-arranged protruding portion is formed by winding a wire and has gaps between portions adjacent to each other along the longitudinal direction of the hollow shaft. The inner peripheral radius CIDmin of a portion, which is the minimum inner peripheral radius of the spirally-arranged protruding portion, is smaller than the outer peripheral radius TODmax of a portion, which is the maximum outer peripheral radius of the distal tip.

Abstract: Dilator includes a hollow shaft having a tapered portion, in which an outer diameter of a distal end is smaller than a outer diameter of a proximal end, and a main body portion which has a distal end located at the proximal end of the tapered portion, extends toward a proximal end side, and has a constant outer diameter. A spirally-arranged protruding portion which is configured of a coil body formed by winding a wire is provided on an outer peripheral surface of the tapered portion and the main body portion. The spirally-arranged protruding portion has gaps between portions adjacent to each other along a longitudinal direction of the hollow shaft. The spirally-arranged protruding portion is not joined to the tapered portion, but is joined to the main body portion at a joint part.

Abstract: A stent delivery system includes a distal end shaft having a tapered portion, a spirally-arranged protruding portion provided on an outer peripheral face of the tapered portion, an inner shaft extending toward a proximal end side in a longitudinal axis direction of the distal end shaft, a self-expanding stent, and an outer shaft. The outer shaft is slidable between a first position where the stent in a contracted state is covered and a second position on the proximal end side of the stent in the longitudinal axis direction of the inner shaft. An outermost periphery of the outer shaft fits inside an outermost periphery of the spirally-arranged protruding portion in a frontal view from the distal end side of the distal end shaft in the longitudinal axis direction.

Abstract: A dilator that includes a hollow shaft including a tapered section having a diameter increasing from a distal end toward a proximal end, and a spirally-arranged protruding portion provided on an outer peripheral surface of the hollow shaft and including spirally-arranged protruding sections and gaps between adjacent spirally-arranged protruding sections along an axial direction of the hollow shaft. The spirally-arranged protruding portion includes an apex section having the greatest height from the outer peripheral surface in a transverse cross-section thereof, and a side surface section facing outward and extending from the apex section toward the outer peripheral surface. The side surface section includes an inclined surface inclined substantially linearly toward at least one of the distal and proximal end direction between the outer peripheral surface and the apex section in the transverse cross-section of the spirally-arranged protruding portion.

Abstract: A dilator that includes a shaft and a spirally-arranged protruding portion. The shaft includes a tapered section, a distal end section, and a body section. The spirally-arranged protruding portion includes spirally-arranged protruding sections provided on outer peripheral surfaces of each of the tapered section, the distal end section, and the body section, and gaps between adjacent spirally-arranged protruding sections along an axial direction of the shaft. At least one of a height t of the spirally-arranged protruding portion at a first location gradually decreases toward a distal end side and a height of the spirally-arranged protruding portion at a second location gradually decreases toward a proximal end side.

Abstract: The dilator includes a hollow shaft and a spirally-arranged protruding portion. The shaft has a tapered portion, a distal end portion positioned on a distal end of the tapered portion, and a main body positioned on a proximal end of the tapered portion, or alternatively the shaft does not have the distal end portion but has the tapered portion and the main body. When the shaft has no distal end portion, a height of a spirally-arranged protruding portion formed on the tapered portion is larger than a height of a spirally-arranged protruding portion formed on the main body. When the shaft has the distal end portion, the height of the spirally-arranged protruding portion on the tapered portion is larger than of spirally-arranged protruding portions on the distal end portion and/or the main body.

Abstract: The dilator includes a hollow shaft and a spirally-arranged protruding portion, and the shaft is either a shaft that has a tapered portion, a distal end portion, and a main body, or a shaft that does not have the distal end portion but has the tapered portion and the main body. When the shaft does not have the distal end portion, the spirally-arranged protruding portion is formed on outer peripheral surfaces of the tapered portion and the main body and has gaps between adjacent sections of the spirally-arranged protruding portion, and when the shaft has the distal end portion, the spirally-arranged protruding portion is formed on outer peripheral surfaces of the tapered portion, and the distal end portion and/or the main body and has gaps between adjacent sections of the spirally-arranged protruding portion.

Abstract: The shaft of a dilator has a tapered part whose outer diameter at a distal end is smaller than at a proximal end, and either a distal end part and a proximal end part, or a proximal end part without a distal end part. If only the proximal end part is provided, the pitch of neighboring sections of a spirally-arranged protruding portion on the tapered part is larger than that on the proximal end part. If both the proximal end part and the distal end part are provided, the pitch of neighboring sections of the spirally-arranged protruding portion on the tapered part is larger than those on the distal end part or the proximal end part.

Abstract: A dilator includes a shaft in a hollow shape whose distal end has a smaller outer diameter than the proximal end, and a connector on the proximal end of the shaft. A spirally-arranged protruding portion on an outer peripheral face of the shaft has gaps between neighboring sections along an axis of the shaft. The shaft has a first location and a second location located closer to the distal end than the first location and having an outer diameter smaller than at the first location. The spirally-arranged protruding portion has, with respect to the axis, an angle of inclination that is larger at the second location than at the first location.