Apparatuses and methods for single disc arthroplasty and multi-segmental spine replacement. The implant assembly includes a first cage (20) adapted to be rigidly attached to a first vertebra, a second cage (20) adapted to be rigidly attached to a second vertebrae, and a spinal disc replacement prosthesis (10) positioned between the first and second vertebrae. The spinal disc replacement prosthesis preferably includes a resilient body having two or more adjustable fluid-filled compartments.