Abstract: An implanted intervertebral prosthesis includes first and second components adapted to attach to a first vertebra and a second vertebra, respectively, that define an intervertebral space. The prosthesis includes a first anchor structure on the first component adapted to enter a grove formed in the first vertebra, and a second anchor structure on the second component adapted to enter a grove formed in the second vertebra. The first anchor structure is offset from the second anchor structure to provide separation of the grooves to preserve vertebral thickness and avoid vertebral splitting. The offset anchor structures can be symmetrically disposed about a midline of the prosthesis or asymmetrically disposed about the midline. In some embodiments, the offset anchor structures comprise elongate anchors shaped as fins or keels. In other embodiments, the offset anchor structures comprise rows of pillars disposed in rows.

Abstract: An intervertebral prosthesis includes a first component adapted to engage a first vertebra and a second component adapted to engage a second vertebra. A row of pillars is disposed on at least one of the components. The row of pillars is adapted to enter a groove and anchor the prosthesis in the intervertebral space. The pillars can be shaped and spaced apart to provide gaps so that bone can grow into the gaps. Additional rows of pillars can be disposed on the components and adapted to enter additional grooves formed in the vertebra.

Abstract: An intervertebral joint assembly includes an upper support and a lower support, each of which has two or more components. The upper and lower support components are arranged in situ to form the upper and lower supports, respectively. By arranging the supports in situ, the supports can be introduced from the back of the patient, for example with an arthroscope. Each of the upper and lower supports has a surface adapted to engage a vertebra and a surface adapted to engage the other support or an intermediate member to form an articulate joint which articulates the joint assembly. In some embodiments, the components of the upper and lower supports are assembled in situ, for example with pivoting, telescoping or bending, to form the upper and lower supports, respectively. The supports can be attached to vertebrae with pedicles screws, and/or other anchors attached to the supports.

Abstract: An intervertebral prosthesis for insertion between adjacent vertebrae includes upper and lower prosthesis plates locatable against respective vertebrae and having opposing, concavely curved recesses therein, and a core located between the plates. The core has opposed, convexly curved surfaces received in the recesses of the plates to allow the plates to slide in articulated manner over the core. The opposed surfaces of the core and the recesses of the plates have cooperating spherical curvatures. The recess of each plate surrounds a locating peg projecting centrally from the base of the recess and is bounded by an annular rim, such that the annular rims of the plates are arranged to contact one another at a predetermined limit of sliding movement of the plates over the core. The peg locates loosely in an opening located centrally in a curved surface of the core, whereby the plates can slide over the core in all directions while the peg holds the core captive.

Abstract: An intervertebral prosthesis for insertion between adjacent vertebrae includes a first prosthesis plate and a second prosthesis plate. The first and second prosthesis plates each comprise a midline, an engagement surface to engage a first vertebra and a bearing surface disposed opposite the engagement surface. The bearing surfaces of the first and second plates are arranged to cooperate to form an articulate joint. A first region of serrations is disposed on the engagement surface of the first plate on one side of the midline of the first plate, and a second region of serrations is disposed on the engagement surface of the first plate on an opposite side of the first plate midline. Each region comprises at least several serrations, and each serration comprises a base attached to one of the plates and tapers from the base to a tip.

Abstract: A prosthetic disc for insertion between adjacent vertebrae includes upper and lower plates and a core having upper and lower curved surfaces disposed between the plates. At least one of the plates and/or the core includes a resilient material for absorbing shock or other forces applied by vertebrae. Optionally, resilient support members may be disposed within the resilient material to connect two portions of a plate or the core. Such support members may be springs, cylinders, wires or other resilient structures. The resilient material is held within the core or plate(s) via a surrounding retaining structure, such as a membrane. The resilient material disposed in one or more components of the prosthetic disc provides for shock absorption.

Abstract: The invention concerns an intervertebral prosthesis placement instrument which can be used to facilitate accurate positioning of a spinal disc prosthesis between adjacent spinal vertebrae. The instrument (10) has opposed jaws 12 formed with tips (24) that are shaped for insertion between the vertebrae. The jaws can be moved apart from one another to distract the vertebrae, allowing the prosthesis to enter between the vertebrae. The jaws also have opposed surfaces which are shaped to embrace the prosthesis between them and to guide the prosthesis into position.

Abstract: A method for inserting an intervertebral disc prosthesis into a space between two vertebrae involves inserting the prosthesis partway into the space under constraint to prevent endplates of the prosthesis from articulating, releasing the prosthesis from constraint, and inserting the unconstrained prosthesis farther into the space. In some embodiments, the method involves grasping the prosthesis with a grasping device to insert the prosthesis partway under constraint, loosing the grasping device to release the prosthesis from constraint, and pushing the prosthesis farther into the disc space using the grasping device and/or one or more separate pusher devices. A system includes a grasping device, at least one separate pushing device, and optionally a vertebral spreading device and/or a vertebral midline indicator device.

Abstract: A spinal midline indicator (10) has a body (14) of radiolucent material for insertion between adjacent vertebrae (18, 20) and a radiographic marker (12) located centrally with the body to indicate the position of the spinal midline (22) in anterior-posterior images when the body is centrally located between the vertebrae. The radiographic marker is typically an elongate metal handle. The body may carry secondary radiographic markers (16) on opposite sides of and equidistant from the handle so that the handle indicates the position of the spinal midline when the body is placed centrally between the vertebrae.

Abstract: A prosthetic disc for insertion between adjacent vertebrae includes a core having upper and lower curved surfaces and upper and lower plates. At least one of the curved surfaces of the core is metallic, and in some embodiments the entire core is metallic. Each plate has an outer surface which engages a vertebra and a metallic inner curved surface which is shaped to slide over one of the curved surfaces of the core. In some embodiments, the center of rotation of the core is free to move relative to the upper and lower metallic plates. In some embodiments, one or more channels extend across one or both of the curved surfaces of the core for allowing passage of bodily fluid to promote lubrication between the core and at least one of the plates.

Abstract: An intervertebral prosthesis for insertion between adjacent vertebrae includes upper and lower prosthesis plates locatable against respective vertebrae and having opposing, concavely curved recesses therein, and a core located between the plates. The core has opposed, convexly curved surfaces received in the recesses of the plates to allow the plates to slide in articulated manner over the core. The opposed surfaces of the core and the recesses of the plates have cooperating spherical curvatures. The recess of each plate surrounds a locating peg projecting centrally from the base of the recess and is bounded by an annular rim, such that the annular rims of the plates are arranged to contact one another at a predetermined limit of sliding movement of the plates over the core. The peg locates loosely in an opening located centrally in a curved surface of the core, whereby the plates can slide over the core in all directions while the peg holds the core captive.

Abstract: A prosthetic disc for insertion between adjacent vertebrae includes a core having upper and lower curved surfaces, upper and lower plates, and peripheral restraining structure on at least one of the upper plate, the lower plate and the core. Each plate has an outer surface which engages a vertebra and an inner curved surface which slides over the curved surface of the core. The peripheral restraining structure serves to hold the core against a curved surface of at least one of the plates during sliding movement of the plates over the core.

Abstract: A prosthetic disc for insertion between adjacent vertebrae includes upper and lower plates, a core disposed between the plates, and at least one projection extending from at least one of the upper and lower curved surfaces of the core into at least one recess of one of the inner surfaces of the plates. The recess is oversize with respect to the projection to allow sliding movement of the plate over the core while retaining the core between the plates during such sliding movement. The projection(s) may include a rod extending through an axial hole in the core, multiple surface features of the core, or the like.