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.

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. Upon deployment of the disc, a height of the disc is increased.

An intervertebral disc includes a superior endplate having an upper vertebral contacting surface and a lower bearing surface, wherein the upper vertebral contacting surface of the superior endplate has a central portion that is raised relative to a peripheral portion of the superior endplate, and wherein the lower bearing surface has a concavity disposed opposite the raised central portion. The disc includes an inferior endplate having a lower vertebral contacting surface and an upper surface, wherein the lower vertebral contacting surface of the inferior endplate has a central portion and wherein the upper bearing surface has a concavity disposed opposite the central portion. A core is positioned between the upper and inferior endplates, the core having upper and lower core bearing surfaces configured to mate with the bearing surfaces of the upper and inferior endplates. The upper vertebral contacting surface of the superior endplate has a different shape than the lower vertebral contacting surface of the inferior endplate.

A dynamic disc assembly has a superior end plate, an inferior end plate, and a core. The core has surfaces of an annular Fresnel shape and a linear Fresnel-like shape combined to control the dynamic range of motion (ROM) movement arranged to match anatomical ROM. The core is interposed between and held against interior surfaces of the superior end plate and the inferior end plate. The assembly further has a pair of coupling cords, one coupling cord at each lateral end of the superior and inferior end plates wherein each lateral end of each end plate has one or more cord connections attached and affixed to the coupling cord to form and retain the dynamic disc assembly.

A method of making an implant having a porous portion is disclosed. The method comprises the following steps: obtaining an artificial foam containing porous portion; scanning the artificial foam to obtain a digital porous model; editing the digital porous model; assembling the digital porous model to form a digital porous block; editing the digital porous block to obtain a digital implant model; forming the implant by printing the digital implant model through a 3D printer. An implant and a method of calculating porosity a porosity of a porous material are also disclosed.

The disclosure provides an implant including first and second interconnected elongated articulating portions with vertebral contacting outer surfaces. The first and second interconnected elongated articulating portions have a first configuration for insertion into a disc space and a second configuration upon deployment in the disc space. In a first configuration the axes of the first and second interconnected elongated articulating portions are substantially axially aligned with each other and in a second configuration the axes of the portions are axially unaligned with each other. The first and second interconnected elongated articulating portions are configured to be deployed in situ from the first configuration to the second configuration by both pivoting. The implant is expandable in the height direction between the vertebral contacting outer surfaces while the implant is inside the disc space by sliding a portion of at least one of the first and second elongated articulating portions.

A method of making an implant having a porous portion is disclosed. The method comprises the following steps: obtaining an artificial foam containing porous portion; scanning the artificial foam to obtain a digital porous model; editing the digital porous model; assembling the digital porous model to form a digital porous block; editing the digital porous block to obtain a digital implant model; forming the implant by printing the digital implant model through a 3D printer. An implant and a method of calculating porosity a porosity of a porous material are also disclosed.

An intervertebral spacer is designed particularly for patients who are not candidates for total disc replacement. The intervertebral spacer maintains disc height and prevents subsidence with a large vertebral body contacting surface area while substantially reducing recovery time by eliminating the need for bridging bone. The intervertebral spacer or fusion spacer includes a rigid spacer body sized and shaped to fit within an intervertebral space between two vertebral bodies. In one embodiment, the intervertebral spacer body has two opposed metallic vertebral contacting surfaces, at least one fin extending from each of the vertebral contacting surfaces and configured to be positioned within slots cut into the two vertebral bodies. Holes within the vertebral body contacting surfaces to provide increased bone on growth surfaces and to prevent subsidence.

The disclosure provides an intervertebral disc and related methods. An upper plate includes an upper vertebra contacting portion and a lower bearing surface portion. The upper vertebra contacting portion includes a convex central portion, and a fin or anchoring element with a transverse hole therethrough. A lower plate has a lower vertebra contacting surface and an upper bearing surface. The lower vertebra contacting surface of the lower plate has a convex central portion. The upper bearing surface has a concavity disposed opposite the convex central portion and wherein the convex central portion and the concavity have nesting curvatures. A core positioned between the upper and lower plates has rigid upper and lower convex surfaces configured to slide and translate over the bearing surfaces of the upper and lower plates.

The invention relates to a modular interim joint prosthesis that can be inserted into a long bone, for replacing an explanted joint endoprosthesis, wherein the interim joint prosthesis has a main body having a main-body coupling segment and has a shaft having a shaft coupling segment and the shaft coupling segment can be detachably coupled to the main-body coupling segment.