Collapsible, rotatable, and tiltable hydraulic spinal disc prosthesis system with selectable modular components
First Claim
1. A modular spinal disc prosthesis system for a surgical implantation of an individually optimized compressible, rotatable and tiltable hydraulic spinal disc prosthesis assembly between a pair of adjacent vertebrae, comprising:
- (a) a pair of selectable opposed crown plate modules with chined edges, consisting essentially of a selectable cephalad crown plate module and a selectable caudal crown plate module, with each selectable crown plate module having a predetermined lordotic angle, a predetermined cross-sectional profile, with each of said selectable opposed crown plate modules being fixedly engageable with a vertebral endplate by a plurality of vertebra engaging members fixedly connected to a vertebra engaging surface of each of said selectable opposed crown plate modules;
(b) at least one selectable, compressible, rotatable and tiltable hydraulic disc prosthesis cartridge module, with each selectable disc prosthesis cartridge module comprising an axial load dampening mechanism of a predetermined size and a predetermined load-bearing capacity, wherein at least one selectable cartridge module is sandwiched connectedly between and coupled to said opposed selectable crown plate modules; and
(c) an insertion instrument to facilitate the surgical implantation of said individualized spinal disc prosthesis assembly, wherein said individualized compressible, rotatable and tiltable hydraulic spinal disc prosthesis assembly, comprised of said selectable disc prosthesis cartridge module connectedly interposed between said pair of selectable opposed crown plate;
wherein said axial load dampening mechanism comprises;
(a) a compressible tiltable bellows assembly containing at least one fluid;
(b) a dashpot assembly; and
(c) at least one biasing member positioned within said bellows assembly in co-axial proximity to said dashpot assembly.
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Abstract
A modular hydraulic spinal intervertebral prosthetic device offering individualized optimization of an implantable disc prosthesis by having selectable crown plates modules with differing lordosis angles and differing cross-sectional profiles, and selectable bellows cartridges having differing load-bearing capabilities. The device offers substantially full physiological degrees of motion, and by the incorporation of both a dashpot mechanism and a biasing element within reversibly displaceable and tiltable bellows provides hydraulic load bearing capability. The bellows assembly is advantageously pre-loaded to sub-atmospheric pressure. The dashpot further increases resistance to lateral sheer loading beyond the bellows convolutions acting alone. Rotational coupling of the upper crown plate and center bearings plate permits normal twisting movements, and spinal flexural freedom is provided by the bellows interposed between the center bearings plate and the lower end plate. The bellows also provides a hermetic seal which prevents any wear debris from migrating to the surrounding body tissue.
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Citations
16 Claims
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1. A modular spinal disc prosthesis system for a surgical implantation of an individually optimized compressible, rotatable and tiltable hydraulic spinal disc prosthesis assembly between a pair of adjacent vertebrae, comprising:
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(a) a pair of selectable opposed crown plate modules with chined edges, consisting essentially of a selectable cephalad crown plate module and a selectable caudal crown plate module, with each selectable crown plate module having a predetermined lordotic angle, a predetermined cross-sectional profile, with each of said selectable opposed crown plate modules being fixedly engageable with a vertebral endplate by a plurality of vertebra engaging members fixedly connected to a vertebra engaging surface of each of said selectable opposed crown plate modules; (b) at least one selectable, compressible, rotatable and tiltable hydraulic disc prosthesis cartridge module, with each selectable disc prosthesis cartridge module comprising an axial load dampening mechanism of a predetermined size and a predetermined load-bearing capacity, wherein at least one selectable cartridge module is sandwiched connectedly between and coupled to said opposed selectable crown plate modules; and (c) an insertion instrument to facilitate the surgical implantation of said individualized spinal disc prosthesis assembly, wherein said individualized compressible, rotatable and tiltable hydraulic spinal disc prosthesis assembly, comprised of said selectable disc prosthesis cartridge module connectedly interposed between said pair of selectable opposed crown plate;
wherein said axial load dampening mechanism comprises;
(a) a compressible tiltable bellows assembly containing at least one fluid;
(b) a dashpot assembly; and
(c) at least one biasing member positioned within said bellows assembly in co-axial proximity to said dashpot assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of preloading a compressible, rotatable and tiltable bellows assembly for an axial-load-bearing shear-resisting prosthetic device comprising the steps of:
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(a) providing a compressible tiltable bellows assembly having a bellows member with a cephalad opening and a caudal opening and formed from a plurality of washers sealingly connected edgewise one to another, and having a cephalad endcap and a caudal endcap fixedly attached to said openings respectively to define thereby a fluid-tight bellows chamber having at least one fluid conduit formed therethrough and fluidly connecting said bellows chamber to an exterior to allow ingress of a fluid in a subsequent filling operation; (b) subsequently, compressing said bellows assembly to a predetermined full stroke excursion, and subsequently applying a constraining member to said compressed bellows assembly to maintain the assembly in a compressed condition; (c) subsequently, fully immersing said compressed bellows assembly in a volume of at least one fluid; (d) subsequently, exposing said immersed compressed bellows assembly to a predetermined sub-atmospheric pressure at a predetermined temperature under a vacuum condition so as to evacuate air from an interior of said bellows assembly; (e) subsequently, admitting an atmosphere of pressure into the vacuum condition to cause thereby said immersed bellows assembly to fill with said at least one fluid; (f) subsequently, returning said compressed fluid-filled bellows assembly to atmospheric pressure; (g) subsequently, sealing said at least one fluid conduit with a sealing member; and (h) subsequently, uncompressing said bellows assembly to expand the assembly to a substantially no-load condition by releasing said constraining member maintaining the mechanically compressed condition of said bellows, whereby a biasing member positioned within the compressed bellows assembly exerts a distracting force to separate said caudal endcap from said cephalad endcap and thereby establish a predetermined sub-atmospheric pre-load pressure within said expanded pre-loaded bellows assembly.
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15. A unitary compressible, rotatable and tiltable hydraulic spinal disc prosthesis assembly for a surgical implantation between a pair of adjacent vertebrae, comprising:
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(a) a cephalad crown plate member with a cephalad vertebral engaging surface formed with a convex profile to provide a substantially fixed complementary juxtaposition with a concave shape of a vertebral endplate; (b) at least one center bearings plate member rotationally coupled to said cephalad crown plate member and further comprising a radial thrust bearing assembly; (c) a caudal crown plate member hydraulically coupled to said center bearing plate member and having a caudal vertebral engaging surface formed with a convex profile to provide a substantially fixed complementary juxtaposition with a concave shape of a vertebral endplate; (d) a bellows assembly having a bellows chamber defined therein, fixedly interposed between said caudal crown plate member and said center bearings plate member; (e) a dashpot device for dampening axial force loads and for resisting shearing force loads between said cephalad crown plate member and said caudal crown plate member, being positionally located between said center bearings plate member and said caudal crown plate member within and coaxial with said bellows assembly; and (f) at least one biasing member in coaxial proximity with said dashpot device for further dampening axial force loads on said unitary compressible, rotatable and tiltable hydraulic spinal disc prosthesis assembly. - View Dependent Claims (16)
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Specification