Methods of separating and/or supporting layers of tissue in the human spine. Such methods generally comprise inserting at least a distal end portion of a guide member between layers of tissue in the human spine wherein the distal end portion defines a predetermined shape. A distraction device is advanced over at least the distal end portion of the guide member so that the distraction device substantially assumes the predetermined shape of the distal end portion of the guide member to form a support structure between the tissue layers that separates and/or supports the tissue layers.