Elastomeric spinal disc nucleus replacement

A spinal disc nucleus replacement comprising:

• an elastomeric sheath surrounding an outside portion of a flexible rod having opposite ends, a portion of said sheath being arranged for sliding along said rod;
• and
• a sheath compactor adapted to slide a portion of said sheath along said rod from a first position to a second position, wherein the second position is more distal into a patient than the first position, wherein in the first position said sheath is in a non-expanded orientation and in the second position said sheath is in an expanded orientation wherein folds of said sheath expand radially outwards from said outside portion of said rod, wherein said elastomeric sheath surrounds the outside portion of the rod both in the non-expanded and expanded orientations and wherein said folds in the expanded orientation comprise a plurality of crests and troughs wherein said rod is flexed into an arcuate shape, and wherein the opposite ends of said rod are fastened together to retain said accurate shape.