Coaxial bi-directional catheter
A deflectable catheter including an outer member having a proximal portion and a distal portion, an elongated column member extending distally from the outer member and an inner member positioned coaxial with the outer member and attached to the column member. The inner member extends distally of the outer member and has a distal tip portion. A reinforcement member is positioned over the column member to restrict axial movement of the column member such that when one of the inner member or outer member is moved with respect to the other, axial compression of the column member is restricted by the reinforcement member causing the distal tip portion of the inner member to deflect laterally.
1. A bi-directional deflectable catheter having a distal tip portion, the catheter comprising:
an outer member having a proximal portion, a distal portion and a first lumen;
an inner member having a proximal portion, a distal portion and a second lumen, the inner member positioned within the first lumen of the outer member, the inner member and outer member being relatively movable; and
an elongated column member extending on only one side of a longitudinal axis of the catheter and having a proximal end and a distal end and positioned external of the inner member, wherein the elongated column member is configured so a first end move axially toward a second end causing buckling of the column member upon movement of one or both of the inner and outer members relative to the other member but the column member is restrained from axial compression and therefore restrained from the first end moving toward the second end to cause buckling so it fails laterally to effect lateral deflection of the distal tip portion of the catheter, the distal tip portion of the catheter being deflectable in a first direction away from a longitudinal axis of the catheter upon such movement of one or both of the inner and outer members relative to the other member, the distal tip portion of the catheter further being deflectable in a second opposing direction away from a longitudinal axis of the catheter;
a reinforcement member positioned over the column member to restrain movement of the first end of the column member toward the second end of the column member.
2. The bi-directional deflectable catheter of claim 1 , wherein the outer member has a proximal section stiffer than a distal section.
3. The bi-directional deflectable catheter of claim 1 , wherein variation of the column member varies a load to deflect the distal tip portion of the catheter.
4. The bi-directional deflectable catheter of claim 1 , wherein the column member is sufficiently thick so multiple buckling points of the column member under load are not created.
5. The bi-directional deflectable catheter of claim 1 , wherein the elongated column member is non-circular in cross-section.
6. The bi-directional deflectable catheter of claim 1 , wherein when the inner member is moved axially by load in the distal direction the column member moves against the wall of the reinforcement member.
7. The bi-directional deflectable catheter of claim 2 , wherein the reinforcement member has a helical configuration.
8. The bi-directional deflectable catheter of claim 1 , further comprising a proximal marker band within an inner diameter of the outer member, the column member positioned between an inner surface of the outer member and an outer surface of the proximal marker band.
9. The bi-directional deflectable catheter of claim 1 , further comprising a distal marker band over the inner member and the column member is between an inner surface of the distal marker band and an outer surface of the inner member.
10. The bi-directional deflectable catheter of claim 1 , wherein the outer member has a central longitudinal axis and the column member is radially offset with respect to the central longitudinal axis of the outer member.