A spinous process fixation assembly and method for securing adjacent spinous processes. The assembly includes one or more lateral plates engageable with one or more insertion plates, respectively. The one or more lateral plates may include a material collection zone for insertion of biologic material prior to implantation. One lateral plates may be rotatable with respect to an adjacent lateral plate. One lateral plates may be movable with respect to an adjacent lateral plate between an extended and a compressed position. A single fixation device may be used to secure spinous processes across two or more levels and promote distraction at each level.
