Patent ID: 8376963

Claim:
A variable-stiffness guidewire comprising: an elongated flexible guidewire body having a proximal end and a distal end; a tensioning wire positioned at least partially within the body, the tensioning wire having a first end mounted to the distal end of the body and a second end having a head attached thereto, the tensioning wire longitudinally movable with respect to the guidewire body to adjust a stiffness of the guidewire; and a collar coupled to the guidewire body and located between the distal and proximal ends, the collar including a conduit through which the tensioning wire passes, the conduit of the collar having an inner surface, the collar further comprising a plurality of protrusions within the conduit, the plurality of protrusions extending from the inner surface of the collar and into the conduit, wherein the plurality of protrusions apply a frictional force onto the tensioning wire to maintain a desired stiffness in the guidewire and wherein the plurality of protrusions remain in contact with the wire.