Steerable catheter
A steerable catheter includes a flexible tube having a distal end and a proximal end. The tube includes a first tube section (sheath body section) the flexibility of which does not substantially change even upon receiving compression force in the axial direction; and a second tube section (deflection section) joined so as to be continuous with the distal end of the first tube section and constituted by a porous tube becoming hard upon being compressed according to the degree of the compression force acting in the axial direction and returning to being soft when the compression force is released. The tube includes operation means (wires) for releasably exerting a compression force compressing the second tube section in the axial direction and a deflection force deflecting the second tube section. According to some embodiments, both operability and insertability of the steerable catheter can be improved.
1 . A steerable catheter comprising a flexible tube having a distal end and a proximal end, wherein:
the tube includes a first tube section having a high rigidity against a compression force in an axial direction and a second tube section joined so as to be continuous with a distal end of the first tube section, and the second tube section being constituted by a porous tube,
in a neutral state in which no compression force is applied to the second tube section, the second tube section has a second axial dimension defined along a longitudinal axis, and
in a compressed state in which a compression force is applied to the second tube section, the second tube section is compressed to a first axial dimension defined along the longitudinal axis, the first axial dimension being smaller than the second axial dimension, and
the catheter operation means for applying the compression force along the longitudinal axis to the second tube section to shorten and harden the second tube section, and releasing the compression force so that the second tube section softens and returns to the neutral state, the operation means for applying and releasing the compression force in a repeated manner, the operation means for applying a deflection force, different from and independent of the compression force, to deflect the second tube section;
the steerable catheter further comprising
a rotational member; and
a pair of gripping portions operatively coupled to the rotational member,
wherein one of the gripping portions is configured to be rotated to apply the deflection force,
wherein both of the gripping portions are configured to be simultaneously pressed to the proximal end to apply the compression force, and
wherein both of the gripping portions are configured to be simultaneously released from the compressed state to release the compression force.
2 . The steerable catheter according to claim 1 , wherein
the tube includes at least three wire lumens mutually spaced apart in a tube wall of the tube and extending from a proximal end section of the tube to a distal end section of the tube, and
the operation means includes at least two wires, a first section of each of the at least two wires is individually inserted through one lumen of a pair of the wire lumens, an intermediate part of each of the at least two wires is folded over a distal end section of the second tube section, a second section of each of the at least two wires is individually inserted through another lumen of the pair of the wire lumens, and the first and second sections of each of the at least two wires reach a proximal end of the first tube section.
3 . The steerable catheter according to claim 1 , wherein
the tube includes at least three wire lumens mutually spaced apart in a tube wall of the tube and extending from a proximal end section of the tube to a distal end section of the tube, and
the operation means includes at least three wires, each of the at least three wires has a distal end connected to a distal end section of the second tube section, is inserted through one of the wire lumens, and has a proximal end reaching a proximal end of the first tube section.
4 . The steerable catheter according to claim 1 , wherein the operation means includes at least two wires,
wherein the operating means is configured to selectively pull a first wire of the at least two wires, a second wire of the at least two wires, or both the first wire and the second wire of the at least two wires simultaneously, and
wherein the operating means is further configured to:
exert the deflection force on the second tube section to deflect the second tube section in a first direction by pulling the first wire of the at least two wires,
exert the deflection force on the second tube section to deflect the second tube section in a second direction, different from the first direction, by pulling the second wire of the at least two wires, or
exert the compression force on the second tube section by pulling both the first wire and the second wire of the at least two wires simultaneously.