The invention relates to a flexible assembly for use in a region of a medical or surgical device. In preferred embodiments, the flexible region comprises a set of pull wires for controllably moving a treatment end of the device, and elements to separate the pull wires and maintain the integrity of the shaft of the flexible region in order to improve the operating aspects of the device. The devices and methods can be especially useful in ablation treatments, such as ablation at cardiac or epicardial tissues.
