An implantable assembly for stabilization of two adjacent spinous processes in a spinal column includes an elongated first component extending along a first axis, an elongated second component extending along a second axis, a hub spacer, means for inserting and securing the hub spacer transversely through the interspinous ligament separating the first and second spinous processes and means for clamping and securing first and second spinous processes of first and second adjacent vertebras, respectively, between the first and second components. The first and second components are arranged opposite and parallel to each other and are separated by the hub spacer.