A spine distraction implant alleviates pain associated with spinal stenosis and facet arthropathy by expanding the volume in the spine canal and/or neural foramen. The implant provides a spinal extension stop while allowing freedom of spinal flexion. An interspinous process implant with a selectably expandable spacer can be placed between adjacent spinous processes. a device implanted between the spinous processes of adjacent vertebrae of the spine can be used for relieving pain associated with the vertebrae and surrounding tissues and structures by maintaining and/or adding distraction between adjacent vertebrae. A tissue expander can be adapted to move from a first insertion position, for ease of implantation between spinous processes, to a second retention position that prevents displacement of the implant. An embodiment of a system can include an implant having a spacer with a thickness and a wing, wherein a first configuration of the wing has a first height substantially similar to the thickness and wherein the wing is adapted to be selectably arranged in a second configuration such that the wing has a second height greater than the first height. A periphery of the implant has a shape generally conformal with a shape of an inner surface of a cannula and a cross-sectional diameter smaller than an inner diameter of the cannula. The cannula is inserted such that a proximal end of the cannula is arranged between the adjacent spinous processes. The implant is then urged into position between the adjacent spinous processes by way of the cannula, and subsequently arranged in a second configuration to fix the implant in position.