Abstract: An intervertebral disc implant for use in the spine including a first part (10) and a second part (20), wherein the first part and second part are configured as a joint prosthesis for the spine. The first part includes one of a concave or convex articulating surface (16) and the second part includes one of the other concave or convex articulating surface (26). One of the concave or convex articulating surfaces is preferably elliptically shaped in at least one direction and does not match and is different than one of the other concave or convex articulating surfaces.

Abstract: An intervertebral implant that is configured to be inserted into an intervertebral space along a direction of insertion is provided. The intervertebral space is defined by a superior vertebral body and an inferior vertebral body that are opposed in a transverse direction. The intervertebral implant may include a body and a first keel. The body may have first and second opposing outer surfaces that are each configured to engage one of the superior and inferior vertebral bodies. The first keel may extend out from the first outer surface in an outward direction and may define a lateral width that increases with respect to an outward direction along the first keel such that an outer portion of the first keel is wider than an inner portion of the first keel. The lateral width may be substantially transverse to the insertion direction and the outward direction.

Abstract: A trial implant assembly is provided that includes a threaded shaft having exterior threading adjacent a distal end and a trial implant that includes a trial base having an interiorly threaded through hole couplable to the distal end of the shaft and a trial head having a superior endplate and an inferior endplate and a support connecting the superior endplate to the inferior endplate. A variety of visualization windows are provided through the trial implant as well as a variety of mechanically adjustable stops to prevent over insertion of the trial head within the intervertebral disc space.

Abstract: A flexible keel is provided for use as a bone anchoring element for use with a range of orthopedic implants having portions configured for anchoring into boney tissue. The flexible keel includes two wings terminating proximally in a pair of outward flares, the wings further spaced from a bone contacting implant surface by a void. The flexibility of the keel wings increases the ease of revision or explantation procedures.

Abstract: An instrument system, associated milling or drilling guide and method include use of a trial implant of a size corresponding to an actual implant for the intervertebral space, with a milling guide mounted on the trial implant. The milling guide includes a longitudinal guide chamber which is tapered from a forward end to a rearward end. The system also includes a cutting tool which is received in the guide chamber in order to form a cutout in an adjacent vertebra. This cutting tool includes a bearing member which pivotally engages the rearward end to form a pivot axis for the cutting tool in the tapered guide chamber. Either the milling guide can be inverted to form the cutout in the other vertebra; or the milling guide can be provided with two guide chambers, to be used with one cutting tool moved between them or two respective cutting tools.