US 6,981,989 B1 · Rotatable and reversibly expandable spinal hydraulic prosthetic device

Abstract

An improved spinal intervertebral prosthetic device that offers all degrees of motion afforded by the anatomic spinal intervertebral disc, and by virtue of the incorporation of a dashpot assembly mechanism within reversibly displaceable bellows, provides hydraulic load bearing capability as well as limiting the maximum pressure that can be exerted on the bellows assembly by limiting the compression stroke of the device. The dashpot assembly also increases resistance to lateral shear loading in excess of the bellows convolutions acting alone. The spinal intervertebral prosthetic device absorbs varying axial loads via hydraulic pressure transfer to the bellows convolutions which can flex in a spring-like fashion. Rotational coupling of the upper crown plate and center bearings plate permits normal twisting movements, and spinal flexural freedom is provided by the bellows that are interposed between the center bearings plate and the lower crown plate.

Claims31

Dependent claims

A rotatable and reversibly expandable spinal hydraulic prosthetic device comprising:

(a) an upper crown plate member for engaging a vertebra;
(b) at least one center bearings plate member rotationally coupled to said upper crown plate member;
(c) a lower crown plate member for engaging a vertebra, coupled to said center bearing plate member;
(d) at least one reversibly displaceable bellows member having a fluid contained therein and sandwiched between said lower crown plate member and said center bearings plate member for resisting shearing force loads between said upper crown plate member and said lower crown plate member;
and,
(e) a dashpot mechanism interposed between said center bearings plate and said lower crown plate member for dampening shock loads.

3 more elements

A rotatable, flexible spinal hydraulic prosthetic device, comprising:

(a) an upper crown plate member for engaging a patient's vertebra;
(b) a lower crown plate member coupled to said upper crown plate for engaging a patient's vertebra;
(c) at least one center bearings plate member disposed between said upper crown plate member and said lower crown plate member, said center bearings plate member being rotationally coupled to said upper crown plate member;
(d) at least one set of biocompatible metallic bellows being positionally located between and coupled to said center bearings plate member and said lower crown plate member, said bellows containing a substantially incompressible biocompatible fluid, wherein said bellows is axially displaceable in response to axial force loads, and flexes laterally as well as in ventral or dorsal directions in response to bending loads;
(e) a dashpot mechanism interposed between said center bearings plate and said lower crown plate member;
and,
(f) at least one set of thrust and radial bearings disposed between said upper crown plate member and said center bearings plate member for permitting rotation of said upper crown plate member relative to said lower crown plate member in response to torque loads.

4 more elements

Dependencies are inferred from the claim text.

Rotatable and reversibly expandable spinal hydraulic prosthetic device

Life of this patent

Rotatable and reversibly expandable spinal hydraulic prosthetic device

Life of this patent

Abstract

Claims31