Artificial intervertebral disc with reliable maneuverability
An artificial intervertebral disc includes an upper retaining member secured to an upper vertebra; a lower retaining member secured to a lower vertebra adjacent to the upper vertebra; and a nucleus member rotatably coupled between the upper and the lower retaining members, with the nucleus member having at least a cushioning filler selected from: gel, foam, elastomers, and shock-absorbing materials filled, formed or pre-formed in the nucleus member for making an artificial intervertebral disc as universally oriented, stably supported, reliably manipulated and minimally invasive.
1. An artificial intervertebral disc comprising:
an upper retaining member adapted to be secured to an upper vertebra;
a lower retaining member adapted to be secured to a lower vertebra adjacent to the upper vertebra; and
a nucleus member rotatably coupled to said upper and lower retaining members by a least a coupling; said nucleus member including a daughter sac filled with a relatively soft cushioning filler in said daughter sac, and a mother bladder circumferentially encasing said daughter sac and having a relatively harder cushioning filler filled in said mother bladder for resiliently flexibly coupling said upper and lower retaining members; whereby said upper retaining member is universally resiliently coupled to said lower retaining member.
2. A disc according to claim 1 , wherein said daughter sac is positioned at a central portion within said bladder of said nucleus member.
3. A disc according to claim 1 , wherein said mother bladder is filled with the relatively hard cushioning filler selected from the group consisting of: high-density elastomers, foams, gels, and fluids; and said daughter sac is filled with relatively soft cushioning filler selected from: low-density elastomers, foams, gels and fluids.
4. A disc according to claim 3 , wherein said elastomer is polyurethane (PU) selected from high density PU to low density PU.
5. A disc according to claim 1 , wherein said nucleus member is formed as a shape selected from oval, spherical and cylindrical shapes, and includes a spherical-shaped upper cup rotatably slidably engaging with a spherical-shaped bottom cover of said upper retaining member; a spherical-shaped lower cup rotatably engaging with a spherical-shaped top cover of said lower retaining member; and said bladder of said nucleus member formed and secured between said upper and lower cups.
6. A disc according to claim 5 , wherein said nucleus member further includes at least a side cover circumferentially sealing and connecting the upper and lower cups; said side cover made of flexible, stretchable and durable materials.
7. A disc according to claim 6 , wherein said side cover is formed as a bellows.
8. A disc according to claim 5 , wherein said nucleus member further includes at least a reinforcing tension spring retained between said upper and lower cups.
9. A disc according to claim 1 , wherein said coupling includes a pivoting ball formed on said nucleus member and a socket recessed in one said retaining member.
10. A disc according to claim 1 , wherein said coupling includes a pivoting ball protruding from said nucleus member, and a socket formed in said retaining member and in said vertebra for rotatably engaging said pivoting ball.
11. A disc according to claim 5 , wherein said nucleus member includes a flexible inner side cover circumferentially sealing the upper and lower cups; and an outermost flexible side cover juxtapositionally circumferentially encasing said inner side cover.
12. A disc according to claim 5 , wherein each said cup and each said cover of said retaining member is respectively formed with a lubricating and wear-resistant surface therein for a smooth slidable rotatable engagement between said cup and said retaining member.