Patent ID: 7559916

Claim:
A controllable stiffness catheter, comprising: a shaft having a stiffness sheath and an access lumen; a stiffness device having a heater and a melting binder in thermal contact with said heater, said stiffness device being disposed in said stiffness sheath, said binder having a transition temperature, being substantially solid at body temperature and softening as said heater warms said binder above said transition temperature; a first electrical conductor electrically contacting said stiffness device; a second electrical conductor electrically contacting said stiffness device and being electrically isolated from said first electrical conductor; a power supply for supplying power; a controller electrically connected to said first electrical conductor, to said second electrical conductor, and to said power supply to form an electrically resistive circuit having said stiffness device as a resistor of said circuit, said controller controlling power supplied to said stiffness device through said circuit and, thereby, controlling a temperature of said heater and said binder; and said stiffness device changes a stiffness of said stiffness sheath between a relatively stiff state when said heater is not energized by said controller and a relatively soft state when said heater is energized by said controller.