Elastomeric spinal disc nucleus replacement
A spinal disc nucleus replacement including an elastomeric sheath ( 12 ) assembled around a rod ( 14 ), a portion of the sheath being arranged for sliding along the rod, and a sheath compactor ( 18 ) adapted to slide a portion of the sheath along the rod from a first position to a second position, wherein in the first position the sheath is in a non-expanded orientation and in the second position the sheath is in an expanded orientation wherein folds of the sheath expand radially outwards from the rod.
1. 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.
2. The spinal disc nucleus replacement according to claim 1 , wherein a stopper is at a distal portion of said rod and said sheath compactor is adapted to push a distal portion of said sheath against said stopper.
3. The spinal disc nucleus replacement according to claim 1 , wherein a removable fastening ring holds a portion of said sheath to said rod.
4. The spinal disc nucleus replacement according to claim 1 , wherein said rod comprises a removable portion.
5. The spinal disc nucleus replacement according to claim 1 , wherein said rod is constructed of at least one of a shape memory alloy and a shape memory polymer.
6. The spinal disc nucleus replacement according to claim 1 , wherein said rod is withdrawable and removable from said sheath.
7. The spinal disc nucleus replacement according to claim 1 , wherein said folds of said sheath expand outwards generally uniformly.
8. The spinal disc nucleus replacement according to claim 1 , wherein said folds of said sheath expand outwards non-uniformly.
9. The spinal disc nucleus replacement according to claim 1 , wherein a distance between folds of said sheath varies axially along said rod.
10. The spinal disc nucleus replacement according to claim 1 , wherein there are more folds on one side of said sheath than on another side of said sheath.
11. The spinal disc nucleus replacement according to claim 1 , further comprising an anchor for attachment to spinal structure.
12. The spinal disc nucleus replacement according to claim 1 , further comprising a guiding wire for introducing said sheath thereover.
13. The spinal disc nucleus replacement according to claim 12 , further comprising another stopper placed at an end of said guiding wire that stops said sheath from progressing further than a length of said guiding wire.
14. The spinal disc nucleus replacement according to claim 1 , wherein said sheath is constructed of at least one of polyurethane, latex, natural rubber, silicone rubber, nylon, and shape memory polymer.
15. The spinal disc nucleus replacement according to claim 1 , wherein said troughs of said elastomeric sheath are adjacent said rod.
16. The spinal disc nucleus replacement according to claim 1 , wherein said folds of said sheath are spaced generally equally from each other.