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 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: 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 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: 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.