A handle assembly is provided for use in navigating a deformable shaft within a body. The assembly includes a first guide member defining first and second linear channels and a second guide member configured for rotation relative to the first guide member. First and second connectors are disposed within, and movable within, the first and second linear channels along first and second parallel axes, respectively, and are configured for coupling to first and second steering wires, respectively. The assembly includes means, such as a flexible coupling connected to the second guide member and the connectors, for translating rotation of the second guide member into linear movement of the first connector in a first axial direction and linear movement of the second connector in a second axial direction, opposite the first axial direction such that the first and second steering wires move in opposite directions.