Patent ID: 8133171

Claim:
A medical device comprising: a flexible shaft having a proximal end and a distal end, said flexible shaft comprising an active deflection section toward the distal end; at least one pull control wire having a first end and a second end, said pull control wire extending from the proximal end and passing through at least a portion of said flexible shaft to the active deflection section, wherein actuation of said at least one pull control wire causes deflection of the active deflection section of said flexible shaft; and said at least one pull control wire being axially displaceable along a length of said flexible shaft during actuation such that a force applied to the first end is transferred to the second end; at least one control wire guide formed of a superelastic metal alloy surrounding said at least one pull control wire along at least a portion of a length thereof, said at least one superelastic metal alloy control wire guide configured as a helical spring providing high resilience and column strength to the flexible shaft, wherein the pull control wire allows the active deflection section to deflect without causing a loss of deflection over time due to repeated use wherein the superelastic metal alloy from which said at least one control wire guide is formed exhibits both shape memory and superelasticity properties.