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: 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.

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: 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 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 spacer for an artificial spinal disc arrangement is provided. The artificial disc arrangement includes an upper plate, a lower plate, and articulating surfaces between the upper and lower plates arranged to permit motion between the upper and lower plates. The spacer has a first surface for contacting the upper plate and a second surface for contacting the lower plate and is of sufficient thickness such that, when disposed between the upper and lower plates, the spacer limits motion between the upper and lower plates. An artificial disc, a method of limiting motion of an artificial disc in a patient, and a method of performing spinal disc surgery are also disclosed.

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: 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 implantable prosthetic joint has a first component for attaching to a first bone and a second component for attaching to a second bone wherein the first and second components are connected in an articulating manner to provide the motion of a prosthetic joint. The joint includes at least one spring to provide compliance to the prosthetic joint. The at least one spring is preloaded in the artificial joint such that the spring is not allowed to move to a completely relaxed position. This preloading of the spring allows the maximum deflection of the spring to be used for shock absorption because the spring does not deform substantially when the implanted prosthetic joint is moved from an at rest position to a loaded or standing position. The prosthetic joints according to the present invention can include artificial hips, knees, shoulders, ankles, and intervertebral discs.

Abstract: An intervertebral disc placement system includes a multi part intervertebral disc, such as a mobile core disc, and an associated placement instrument. The placement instrument holds the disc securely with the disc endplates angled for ease of placement of the disc into an intervertebral disc space and quickly releases the implant within the disc space. The disc includes upper and lower plates having notches in inner surfaces for engagement of the placement instrument. The placement instrument has a rotatable key configured to fit into the first and second notches to grasp the disc from the interior and eliminate the need for an external grasping mechanism which could interfere with disc placement.

Abstract: A prosthetic intervertebral disc is formed of first and second end plates sized and shaped to fit within an intervertebral space and to be implanted from the back of the patient, thereby decreasing the invasiveness of the procedure. The posterior approach provides for a smaller posterior surgical incision and avoids important blood vessels located anterior to the spine particularly for lumbar disc replacements. The first and second plates are each formed of first, second and third parts are arranged in a first configuration in which the parts are axially aligned to form a low profile device appropriate for insertion through the small opening available in the TLIF or PLIF approaches described above. The three parts of both of the plates rotate and translate with respect to one another in situ to a second configuration or a deployed configuration in which the parts are axially unaligned with each other to provide a maximum coverage of the vertebral end plates for a minimum of insertion profile.

Abstract: A prosthetic intervertebral disc includes an upper plate and a lower plate and employs congruent stepped features to provide limited articulating motion between the plates. The stepped features can be used to provide articulating motion of a rocking type rather than a rubbing or translating type of motion provided in many artificial discs. Each of two parts of the intervertebral disc includes two or more stepped bearing surfaces, having curved or flat shapes, which mate with one another to provide the articulation to the disc. The stepped features can be designed to restrict motion in flexion-extension or lateral bending to less than a predetermined angle. The stepped design can be modified to either allow or prevent rotational motion between the plates. The limited motion disc substantially prevents translation, however some limited translation can be provided by modification of the relative sizes of the stepped features.

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.

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, in one embodiment, includes upper and lower prosthesis plates and a movable core. The prosthesis plates and optionally the core are formed of polyaryletherketone (PAEK) for improved imaging properties. A metallic insert is provided on each of the PAEK prosthesis plates providing a bone ongrowth surface.

Abstract: An intervertebral disc is provided having an upper plate, a lower plate, and a core. The upper and lower plates include outer vertebral body contacting surfaces which are provided with attachment enhancing features to ensure bone integration. The attachment enhancing features shown include one or more fins, serrations and teeth. An opposite surface of the plates from the vertebral body contacting surfaces is formed with a recess which serves as a bearing surface for the core. In order to form an intervertebral disc with a lower disc height, at least one of the recesses is provided opposite a corresponding dome shaped portion on the vertebral body contacting surfaces. This allows the plates to be formed with a thinner profile for a smaller overall disc height. In addition to providing a lower overall height to the artificial disc, the dome shaped portion of the plates also provides a more anatomically shaped outer vertebral body contacting surface.

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 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.