Manipulators employing multiple deformable elongate members

Abstract

A manipulator is configured with a set of substantially concentric, elongate members configured such that relative rotation and translation of the elongate members adjusts both the spatial position and orientation of the distal end of the manipulator and the spatial positioning of the manipulator along its length. In one arrangement, the elongate members are pre-curved such that the distal end portions of the elongate members have generally arcuate shapes in a resting state. When the three elongate members are combined in a substantially concentric manner, the overall shape of the manipulator is a composite of the individual elongate member shapes. Varying the relative translation and rotational orientation of the component elongate members achieves a family of resulting manipulator shapes as well as a desired spatial position and orientation of the distal end portion of the manipulator.

1 . A needle manipulator for use in percutaneous procedures, comprising:
 a set of concentrically arranged elongated tubular members, at least two of the elongated tubular members having respective rest curvatures and a sufficiently non-dominant stiffness relationship that a distal tip of the needle manipulator can be advanced and steered through tissue along a generally curved path to a desired tissue location without requiring forceful steering interaction between the distal tip and surrounding tissue, the two elongated tube members being configured for advancing the distal tip by a combination of (1) rotation of the two elongated tubular members together about a longitudinal axis of the needle manipulator, (2) relative longitudinal translation between the two elongated tubular members, and (3) relative rotation between the two elongated tubular members with respect to the longitudinal axis of the needle manipulator; and   a needle member at a distal end of one of the two elongated tubular members to provide for low-force advancing of the distal tip through the tissue.   
     
     
         2 . A needle manipulator according to  claim 1 , wherein the two elongated tubular members have a balanced stiffness relationship of substantially equal stiffness. 
     
     
         3 . A needle manipulator according to  claim 1 , wherein a third one of the elongated tubular members has a dominant stiffness relationship of substantially greater stiffness than the two elongated tubular members. 
     
     
         4 . A needle manipulator according to  claim 3 , wherein the third elongated tubular member is an outer member in which the two elongated tubular members are disposed. 
     
     
         5 . A needle manipulator according to  claim 3 , wherein the third elongated tubular member is an inner member about which the two elongated tubular members are disposed. 
     
     
         6 . A needle manipulator according to  claim 1 , wherein the needle member includes a stylet carried by the distal tip of the manipulator. 
     
     
         7 . A needle manipulator according to  claim 1 , wherein the needle member includes a beveled tip potion of one of the two elongated tubular members. 
     
     
         8 . A needle manipulator according to  claim 7 , wherein the one elongated tubular member is an inner one disposed within the other one of the two elongated tubular members. 
     
     
         9 . A needle manipulator according to  claim 1 , wherein each of the elongated tubular members has a substantially circular cross section along its length. 
     
     
         10 . A needle manipulator according to  claim 1 , wherein at least one of the elongated tubular members has a non-symmetric cross section along at least a portion of its length. 
     
     
         12 . A needle manipulator according to  claim 1 , wherein at least one of the elongated tubular members has a variable stiffness along its length. 
     
     
         13 . A needle manipulator according to  claim 12 , wherein the stiffness varies in a continuous manner along the length of the at least one elongated tubular member. 
     
     
         14 . A needle manipulator according to  claim 12 , wherein the stiffness varies in a discontinuous manner along the length of the at least one elongated tubular member.