Steerable sheath with variable curve span
A guiding sheath assembly has a shaft that is operable to define more than one deflection curvature and defines a lumen to slidably receive a cardiovascular catheter. The guiding sheath assembly includes a proximal section, a distal section, and a stiffener member. The proximal section has a proximal shaft that defines a proximal lumen extending distally along a longitudinal axis to the distal section. The distal section has a distal shaft that defines a distal lumen that is configured to be biased (e.g., resiliently biased) laterally away from the longitudinal axis. The stiffener member is a rigid elongate member, such as an inner tubular member, that is configured to counteract the bias of the distal shaft. Longitudinal movement of the stiffener member relative to the distal section enables an operator to select and set a deflection curvature of the more than one deflection curvature.
1 . A shaft assembly, comprising:
(a) a proximal section extending distally along a longitudinal axis of the shaft assembly, the proximal section comprising a proximal shaft defining a proximal lumen;
(b) a distal section extending distally from the proximal section, the distal section comprising a distal shaft defining a distal lumen configured to align with the proximal lumen of the proximal shaft, the distal section being configured to be biased to deflect laterally away from the longitudinal axis of the shaft assembly into a deflection curvature having a width, the distal section being configured to fit within a cardiovascular anatomical passageway; and
(c) a stiffener member assembly comprising a collar, and a first stiffener member attached at one end of the first stiffener member to an outer wall of the collar, the stiffener member assembly configured to selectively translate in a direction of the longitudinal axis such that the collar translates within the proximal lumen or the distal lumen and the first stiffener member translates within a first side lumen in the proximal shaft and the distal shaft, the first side lumen being off-axis relative to the proximal lumen and the distal lumen, the first stiffener member being configured to counteract the lateral bias of the distal section and thereby reduce the width of the deflection curvature based on a longitudinal position of the first stiffener member relative to the distal section.
2 . The shaft assembly of claim 1 , the width of the deflection curvature ranging from approximately 0 mm to approximately 55 mm.
3 . The shaft assembly of claim 2 , the width of the deflection curvature ranging from approximately 20 mm to approximately 55 mm.
4 . The shaft assembly of claim 1 , further comprising one or more second stiffener members attached to the outer wall of the collar, and one or more second side lumens in the proximal section and the distal section, each of the one or more second stiffener members being disposed within a corresponding one of the one or more second side lumens in the proximal section and the distal section.
5 . The shaft assembly of claim 4 , further comprising an actuator coupled to the first stiffener member and the one or more second stiffener members, the longitudinal position comprising two or more different longitudinal positions, and the actuator being configured to move the one or more second stiffener members between the two or more different longitudinal positions.
6 . The shaft assembly of claim 1 , further including one or more pull wires operable to control the lateral deflection of the distal section.
7 . The shaft assembly of claim 1 , further comprising an actuator configured to selectively deflect the distal section.
8 . The shaft assembly of claim 7 , the actuator being operable to linearly translate the first stiffener member.
9 . The shaft assembly of claim 7 , the actuator being rotatable to linearly translate the first stiffener member.
10 . The shaft assembly of claim 1 , further including one or more pull wires operable to control the lateral deflection of the distal section, the collar being attached to the one or more pull wires.
11 . The shaft assembly of claim 1 , further comprising:
(a) one or more pull wires operable to control the lateral deflection of the distal section; and
(b) a pulley, the one or more pull wires engaging the pulley, the pulley being configured to change a direction of force administered to the one or more pull wires.
12 . The shaft assembly of claim 11 , the collar being proximal of a distal tip of the proximal shaft and the collar being affixed to the one or more pull wires that extend along a first axis parallel to the longitudinal axis, a portion of the one or more pull wires wrapping around the pulley, the one or more pull wires being operable to translate through a second axis located opposite the first axis and parallel to the longitudinal axis, the one or more pull wires extending distally along the second axis and being affixed to an actuator, and the actuator being affixed to the first stiffener member.
13 . A sheath assembly comprising:
(a) the shaft assembly of claim 1 , the proximal lumen and the distal lumen being sized to slidably receive a catheter; and
(b) a handle assembly including a proximal opening configured to receive the catheter, the shaft assembly extending distally from the handle assembly, the proximal opening being in communication with the proximal lumen and the distal lumen.
14 . The shaft assembly of claim 1 , further comprising an actuator coupled to the first stiffener member, the longitudinal position comprising two or more different longitudinal positions, and the actuator being configured to move the first stiffener member between the two or more different longitudinal positions.
15 . The shaft assembly of claim 14 , the two or more different longitudinal positions comprising at least three different longitudinal positions, each of the at least three different longitudinal positions resulting in a different width of the deflection curvature corresponding to a respective one of the at least three different longitudinal positions.