Patent ID: 8808169

Claim:
A control device for a medical instrument having a shaft, comprising: (a) a first control cable disposed within the shaft of the medical instrument, wherein the first control cable is configured to be selectively tensioned to steer a tip of the medical instrument, the first control cable having a first elongate member surrounded by a first outer sheath; (b) a first spring disposed to exert a biasing force in a distal direction against a proximalmost end of the first outer sheath, and reduce a force in the first outer sheath caused by a first bend in the shaft; (c) a second control cable disposed within the shaft of the medical instrument, wherein the second control cable is configured to be selectively tensioned to steer the tip of the medical instrument, the second control cable having a second elongate member surrounded by a second outer sheath; and (d) a second spring disposed to reduce a force in the second outer sheath caused by a second bend in the shaft, wherein the first spring is independently moveable relative to the second spring, and the first control cable and the second control cable control movement of the shaft in opposing directions.