US Patent 7736323 Controllable stiffness catherer guide device

A guide device for guiding a therapy catheter in a body duct has a flexible sleeve that is dimensioned to be inserted into the body duct. A first elongate body and one or more second elongate bodies are disposed inside the sleeve in side-by-side relation and extend lengthwise along the sleeve. Magnetic attraction and repulsion forces are selectively created between the first body and the one or more second bodies to vary the stiffness of the guide device. In an alternative arrangement, the first elongate body is a stretchable hollow body and plural second elongate bodies are disposed inside the sleeve around the outer circumference of the first body, the first and second bodies being movable relative to one another to impart flexibility to the guide device. The first body is stretched radially outwardly by introducing pressurized fluid inside the first hollow body to radially press the second bodies against the inner wall of the sleeve to impart stiffness to the guide device.