An interspinous process device includes a first plate, a second plate, and a transverse member between the first plate and the second plate, wherein the second plate is adjustably coupled to the transverse member. A post is coupled to the transverse member and a spring mechanism is disposed between the post and the first plate. The spring mechanism is configured to provide a preloaded compression force to the first and second plates. Methods of implanting the interspinous process device using an inserter tool are also disclosed.
