A spinal facet prosthesis for a diseased or painful facet joint comprises a superior component and an inferior component. The superior component is roughly conical or pyramidal in form and is fastened to and over the distal tip of the inferior articular process of the diseased or painful facet joint. The inferior component is also roughly conical or pyramidal in form with one side elongated postero-medially and distally. The outer surface of the elongated side of the inferior component is of low friction, such as polished chromium coating or medical grade high-density polyethylene. The inferior component is fastened to and over the superior articular process of the diseased or painful facet joint. Each component is made of a biocompatible material. The inner surface of each component which is in contact with its respective articular process is coated with a porous coating to enhance the adhesion of each component to its respective articular process.
A prosthetic implant for replacing a facet joint of a spinal motion segment includes a generally conical superior component adapted to be implanted at a surgically prepared site on a lower articular process of a cephalad vertebra of a spinal motion segment, and a cup-shaped inferior component adapted to be implanted at a surgically prepared site on a superior articular process of a caudad vertebra of the spinal motion segment.
A posterior vertebral joint prosthesis is provided so that the left or right posterior vertebral joint prosthesis (1, 2) presents a smooth bearing surface (11, 11a, 11b, 17, 17a, 17b) and and which surface presents antero-posterior curvature.
An article including a facet prosthesis at least partially mounted in a lumen artificially formed between superior and inferior halves of a facet joint, and an elastomeric cushioning element disposed in the facet prosthesis.
A device for replacing all or part of the posterior vertebral articular process (3, 13), engaging a support (7) and members for anchoring same to the vertebra, wherein each complete (5) or partial (1, 11), upper (1, 5) and/or lower (11) prosthesis mimics the anatomical shape of the posterior vertebral articular process and comprises artificial sliding surfaces (2, 12) facing one another between at least two adjacent vertebrae while adapting to the physiological orientation thereof, and the anchoring members comprise a support (7) with a convex surface matching and engaging at least one portion of the concave surface of the posterior arch of the vertebra on at least one side of the spinous process (9), and rigidly connect at least one separate portion of the support (7), to a corresponding separate portion of the vertebra.
Surgically installed prostheses replace either the caudal portion of a natural facet joint, the cephalad portion of a natural facet joint, or both. The prostheses are readily attached to the pedicles of a vertebral body and support at least one element that defines an artificial facet joint structure. The caudal facet joint structure is sized and located to articulate with the cephalad facet joint structure. Together, the prostheses form a total facet replacement system. The system is suitable for use in virtually all levels of the spine.
