An interspinous spacer implant includes first, second, third, and fourth arms that are divided into pairs that are relatively rotatable. In an insertion configuration, the first and third arms are disposed close together, and the second and fourth arms are disposed close together. Relatively rotating the arm pairs results in a deployed configuration where the first and fourth arms are disposed close together and the second and third arms are disposed close together, with each set of arms forming a respective saddle for receiving a corresponding spinous process. Related methods are also described.
