An inflatable central distractor is inserted in to a disc space between two vertebral endplates. A perimeter balloon is inserted into the disc space in such a manner as to surround the central inflatable distractor. The perimeter balloon and the central inflatable distractor are simultaneously expanded such that as the central inflatable distractor expands the perimeter balloon surrounds the central inflatable distractor and such that the central inflatable distractor and the perimeter balloon, when expanded, contribute to forcing adjacent vertebral endplates apart.