Systems and methods for stabilizing or adjusting the position of at least one spinal motion segment, such as a posterior element distraction system. The system includes an implantable member having at least one of a lateral member and a transverse member. The lateral member may be expandable in at least one dimension, for example, in a direction along the axis of the spine. The expandable member may be an inflatable balloon, expandable scaffolding, strut, or combination thereof and may provide stability and anchoring to the implantable member. The transverse member is configured to engage the spinous process and may extend from the lateral member or may extend between two laterally-opposed members. For example, the transverse members may be configured to engage an outer surface of the spinous process, and as such, act as a saddle or cradle.
