Abstract: An artificial disc device for replacing a damaged nucleus is disclosed. In one form, the device may be inserted in components such that the device may be assembled within and retained by the natural annulus therein. In another form, the device may be inserted into the natural annulus in a collapsed or compressed state or arrangement and then be expanded within and retained by the annulus therein. In a further form, the device may be provided with a releasable connection so that the device may be connected in an insertion configuration and may be released in an operable configuration. Insertion tools and methods are also disclosed.

Abstract: An artificial cervical vertebrae composite joint is composed of two upper and lower fixing members disposed vertically symmetrically, a cervical vertebrae body member, and two connection members, the cervical vertebrae body member being connected between the fixing members through the connection members. The fixing members each have an L shape and comprise a front wing part and a base part. A locking screw hole is formed in the front wing part, and a skidproof groove provided with an inverted tooth and a protrusion is disposed on a middle portion of the base part. A bone grafting hole is transversely disposed through a middle portion of the cervical vertebrae body member, and two cavities are disposed on both upper and lower sides of the cervical vertebrae body member at an axial center of the cervical vertebrae body member to mount the connection members.

Abstract: An artificial disc prosthesis is provided. The prosthesis enables spinal segment alignment by having a variable height across its surface. The variable height is achieved by an asymmetric artificial nucleus or by at least one variable height end plate. The prosthesis may have a central keel on one end plate and an offset pair of keels on a second end plate. The nucleus may engage a slot or trough in an inner surface of an end plate. The trough can be open on the posterior or anterior end to allow the nucleus to slide into the trough without undue distraction of adjacent vertebrae. The nucleus can be prevented from moving out of the trough by inserting a stop in the trough.

Abstract: An articular disc prosthesis and method of implanting the same within an intervertebral space between adjacent vertebral bodies. The prosthesis includes a pair of articular components and an articular ball disposed therebetween. Each of the articular components includes an outer shell portion and a removable inner insert portion. The insert portion includes a concave articular surface sized and shaped to receive a portion of the articular ball to provide articulating motion between the articular components. The outer shell portion includes a central hemi-cylindrical portion, a pair of laterally extending flanges, and an axially extending lip. Following removal of the natural intervertebral disc, a pair of hemi-cylindrical recesses are formed along a central region of the adjacent vertebral bodies to a predetermined depth.

Abstract: An intervertebral joint prosthesis having a ball component (22) for engagement with a first vertebra (26) and a trough component (24) for engagement with a second vertebra (27) adjacent to the first vertebra is disclosed. The trough component (24) includes a generally concave surface (50) having a substantially flat portion (52). When the ball component (22) and the trough component (24) are engaged to their respective vertebrae, the ball component (72) and the trough component (24) engage each other, permitting rotation and translation of the vertebrae with respect to each other. Both components include a flange (34,56) for engaging a vertebra. The invention also contemplates a method for and a tool for use in implanting a two-piece intervertebral joint prosthesis.

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 method of implanting an intervertebral disc prosthesis in a patient comprises selecting a superior and inferior endplates from a plurality of endplates having different endplate features. The different endplate features include different structural and material composition features. In addition, a core is selected from a plurality of cores having different core features such as different structural and material composition features. In one embodiment, the core is a composite core comprised of a first material and a different second material. After the endplates and core are selected, the intervertebral disc prosthesis is assembled with the selected core positioned between the selected endplates. The assembled intervertebral disc prosthesis is then positioned on an insertion tool and implanted in the patient.

Abstract: In an intervertebral implant having an abutment element for abutment on at least one vertebral body, in order to be able to apply pulling forces to the abutment element without the risk of damage to the abutment element, it is proposed that the abutment element carry at a side edge a pull element which extends along the side wall of the abutment element and is held on the abutment element by pull members extending at the sides of the abutment element in the direction towards the opposite side edge, the pull element being made of a material whose tensile strength is greater than the tensile strength of the material of the abutment element, and that an interspace for receiving a handling instrument engaging the pull element from behind be arranged at least in a section along the pull element between the pull element and the abutment element. A handling instrument for handling such an intervertebral implant is also described.

Abstract: Provided is a device and method for replacing a diseased or damaged intervertebral disc in the spine of a patient. The device provided having at least two units, each of the units having an articulation surface and a bone contacting surface, the articulation surfaces of each of the at least two being in articulating opposition one to the other, one of which having a convex articulation surface and the other having a complementary concave articulation surface. The bone contacting surfaces being provided with bone implantation securing elements such as keel type or spike type protrusions. Also provided is a method of implanting the device into an intervertebral space from a posterior approach.

Abstract: An implant system that includes a concave spherical-segment-shaped socket part and a corresponding convex spherical-segment-shaped joint part is provided. The joint part rests in the socket part, wherein at least three support elements that describe a spherical triangle or a spherical polygon are arranged on the surface of the joint part or on the surface of the socket part.

Abstract: Non-articulating semi-rigid spinal implants include upper and lower rigid endplates that define at least one aligned pair of rigid male and female members. The respective female member having an interior facing cavity and the respective male member facing toward the female cavity. At least one elastic member resides in each female member cavity. The device can include an optional housing with at least one bore for each of the at least one aligned pairs of female and male members. The housing bore is sized and configured to snugly encase each respective aligned pair of endplate male and female members while leaving an upper outer surface of the upper endplate and a lower outer surface of the lower endplate exposed.

Abstract: An artificial disc is provided which more closely matches the movement of the natural spine. The artificial disc uses one or more projections and corresponding recesses to provide a sliding articulation. The artificial joint is inherently stable in that compressive forces placed on the disc such as the weight placed upon the joint or the tension of surrounding tissues urges the joint towards a neutral position and not farther away from a neutral position.

Abstract: An intervertebral disc replacement has two members attached to vertebral body endplates of two adjacent vertebrae. The two members are formed with respective articulation surfaces which form at least part of an articulation arrangement. When loaded with compressive axial force, the articulation arrangement supports the vertebral contact surfaces against the compressive force to ensure a predefined minimum intervertebral spacing, and allows a range of turning motion in all directions. The articulation arrangement is formed to provide an increase in the intervertebral spacing as a smooth function of angular displacement from a neutral position over at least part of the range of motion in each direction for each direction of motion, thereby providing motion attenuation and restoring forces.

Abstract: An intervertebral implant with a central axis, a top part, a bottom part, a joint comprising a joint part and a joint shell, and a joining means. The top part has a top apposed surface that is suitable for placing it on a vertebra situated above it; The bottom part has a bottom apposed surface, that is suitable for placing it on a vertebra situated below it. One of the two parts is operatively associated with a convex joint part and the other part to a matching joint shell. The joint part and the joint shell are mounted against one another in a sliding manner such that the top part and the bottom part can rotate relative to one another at least about one axis of rotation. The joining means holds the top part and the bottom part together without impairing the capability of the joint to pivot while allowing a clearance between the joint part and the joint shell.

Abstract: A dynamic interbody device for a human spine is provided to stabilize a human spine. In some embodiments, the dynamic interbody device includes a first member and a second member. In some embodiments, dynamic interbody device includes a first member, a second member and a third member. In some embodiments, the dynamic interbody device may include a bridge. The bridge may be used to couple the dynamic interbody device to a posterior stabilization system. In some embodiments, two dynamic interbody devices may be placed in a disc space between vertebrae.

Abstract: An implant retention device is provided to assist in restraining movement of a nuclear implant and to assist in preventing expulsion of the nuclear implant through an incision portal or defect in the annular wall. In one form, the implant retention device comprises an expulsion prevention member associated with the nuclear implant and is configured to transition between an unexpanded position and an expanded position. In another form, a method for restraining a nuclear implant includes cutting an opening in the annulus, shifting an implant retention device into an unexpanded position, inserting the implant retention device through the opening, and shifting the retention device to an expanded position.

Abstract: An intervertebral implant, alone and in combination with an insertion tool for inserting same and a method for inserting same. The implant has upper and lower parts which have universal movement relative to each other. Each of the upper and lower parts also has a surface engaging an adjacent vertebrae. Each part has a keel extending from said surface into a cutout in the adjacent vertebrae, and each keel has an anterior opening recess therein. An insert tool has a pair of arms which are received in the recess of the keels through the anterior opening to securely hold and insert the implant. Projections and matching indentations in each arm and the base of its recess securely attached each arm within its keel.

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 prosthesis assembly replaces a cephalad portion of a left natural facet joint on a vertebral body and a cephalad portion of a right natural facet joint on a vertebral body. The prosthesis assembly has a left prosthesis body accommodating fixation to the vertebral body at or near a left pedicle and without support by a lamina. An artificial left facet joint structure carried by the left prosthesis body and is adapted and configured to replace a cephalad portion of the left natural facet joint. The prosthesis assembly further has a right prosthesis body accommodating fixation to the vertebral body at or near a left pedicle and without support by a lamina. An artificial right facet joint structure is carried by the right prosthesis body and is adapted and configured to replace a cephalad portion of the right natural facet joint.

Abstract: An intervertebral spacer device may include first and second plates, each having inner and outer surfaces thereof, the plates may be disposed in a spaced apart relationship such that the inner surfaces face toward one another, and the outer surfaces face away from one another, the first plate including a retaining wall extending outwardly from the inner surface of the first plate; and a belleville washer, having narrow and wide ends thereof, may be disposed with said wide end contacting said inner surface of said first plate within said retaining wall, such that a compressive load applied to the outer surfaces of said plates is counteracted by said belleville washer, said belleville washer including a plurality of radially spaced concentric groove.

Abstract: A cervical intervertebral prosthesis includes two connection plates adapted for connection to adjacent vertebral bodies and a hinge core. The hinge core and one connection plate together form a hinge with a concave hinge surface on the hinge core and with a complementary convex hinge surface on the connection plate. The hinge core bears on the other connection plate via a slide surface which extends substantially parallel to the direction of the connection plate and which permits a relative movement in this direction and is surrounded by an edge limiting this relative movement. The concave hinge surface encloses the convex hinge surface within a solid angle of at least 90°. The part of the concave hinge surface lying within this solid angle lies inside the recess surrounded by the edge. The stability of the prosthesis with respect to laterally incident forces is thereby increased.

Abstract: A spacer for inserting between vertebral members. The spacer has a non-spherical shape with an anterior section having a first shape and a posterior section having a different shape. An attachment means is positioned within the posterior section, and may include a receiver for attachment with an insertion device, and an anti-rotation mechanism for assistance in removing the spacer from the insertion device. Embodiments of using the spacer is also disclosed which may include inserting the spacer between the vertebral members in a generally posterior approach. Once inserted, the insertion device acts with the anti-rotation device to remove a connection mechanism from the receiver. The spacer remains between the vertebral members and provides relief to the patient.

Abstract: A spinal prosthesis system includes: an anterior portion having an upper component and a lower component, the upper and lower components capable of relative movement about a first point; a posterior portion separate from the anterior portion, the posterior portion having an upper portion and a lower portion, the upper and lower portions capable of relative movement concentric to the upper and lower components about the first point. In another form, a method includes: determining a motion profile of a vertebral motion segment; determining a point of rotation based upon the motion profile; and manufacturing a spinal stabilization system having an anterior portion and a posterior portion, the anterior and posterior portions each having a center of rotation located at the point of rotation.

Abstract: An intervertebral implant system for positioning between an upper vertebra and a lower vertebra is provided. The implant system comprises an intervertebral implant and a staple. The implant comprises an inferior plate and a superior plate, while the superior plate has a vertebral surface facing the upper vertebra and the inferior plate has a vertebral surface facing the lower vertebra. There are two grooves on at least one vertebral surface extending at an angle outward from a centerline on the vertebral surface as they extend from the anterior portion of the plate toward the posterior portion of the plate. When in use, the staple is associated with the two grooves for maintaining stability of the intervertebral implant and preventing backing out of the intervertebral implant. The staple also has two arms and has a generally rectangular shape prior to use.

Abstract: An arthroplasty spinal prosthesis with first and second vertebra contacting members that are configured for engaging opposing vertebrae An articulation is supportively associated with the contacting members to allow relative pivotal and translational motion therebetween over anterior-posterior and lateral pivotal axes, and over anterior-posterior and lateral translational axes. This motion allows the opposing vertebrae to pivot and translate with respect to each other. The articulation is configured to permit translational movement substantially uncoupled from the pivoting movement.

Abstract: A prosthetic joint includes: (a) first member having a balanced centroidal axis, and comprising a rigid material and a concave interior defining a cup surface, the cup surface including: (i) a cantilevered first flange defining a wear-resistant protruding first contact rim, the first flange being asymmetric relative to the balanced centroidal axis; and (ii) a cantilevered second flange defining a wear-resistant protruding second contact rim; (b) a second member comprising a rigid material with a wear-resistant, convex contact surface; (c) where the first and second contact rims bear against the contact surface of the second member, to transfer loads between the first and second members, while allowing pivoting motion therebetween; and (d) wherein the flanges are shaped and sized so as to deform elastically and permit the first and second contact rims to conform in an irregular shape to the contact surface, when the joint is under load.

Abstract: An intervertebral device includes a first plate having an outer face and an inner face, and a second plate juxtaposed with the first plate, the second plate having an outer face, an inner face that opposes the first plate and a concavity that opposes the first plate. The device includes an elongated member extending from the first plate toward the second plate, the elongated member having a distal end with a spherical surface that is engageable with the concavity of the second plate for providing an articulating joint between the first and second plates. The device also includes a resilient member in contact with the elongated member for counteracting compressive loads on the plates, the resilient member being surrounded by the concavity of the second plate.

Abstract: A prosthesis replaces all or a portion of a natural facet joint on a vertebral body. The prosthesis has a prosthesis body accommodating fixation to the vertebral body at or near a pedicle and without support by a lamina. The prosthesis body has a fastening element installed within the vertebral body at or near a pedicle. The prosthesis further has an artificial facet joint structure carried by the prosthesis body at a location spaced from the fastening element. The artificial facet joint structure is adapted and configured to replace all or a portion of a natural facet joint.

Abstract: An artificial intervertebral disc for at least partially replacing a diseased or damaged intervertebral disc. The artificial disc includes a concave-convex articulating surface. The artificial disc can be used in the cervical region of the spine, where a concave-convex articulating surface is advantageous for improved anatomical fit and region appropriate kinematics. The artificial disc of the present invention also includes an anchor for attachment to bone.

Abstract: A spinal prosthesis system having a caudal prosthesis provided with a pair of pedicle anchors for coupling to an inferior vertebral body, the caudal prosthesis including an artificial caudal facet joint structure comprising a pair of caudal bearing surfaces. A cephalad prosthesis is provided with a second pair of pedicle anchors for coupling to a superior vertebral body. The cephalad prosthesis includes an artificial cephalad facet joint structure having a pair of cephalad bearing surfaces. An artificial facet joint is formed between the adjoining vertebral bodies by articulation of the artificial caudal facet joint structure with the artificial cephalad facet joint structure.

Abstract: An artificial disc implant and associate methods and instrumentation are provided for the artificial disc implant that includes opposite vertebral endplate members and a spacer member between the vertebral endplate members. An anchoring member extends from at least one of the vertebral endplate members toward an adjacent vertebral endplate when the implant is positioned between vertebrae. The anchoring member can be received in an anchor seat formed in the adjacent vertebral endplate without requiring the artificial disc implant to be impacted into the space between vertebrae to engage the anchoring member in the seat.

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, in particular for the cervical spine, includes a first cover plate to be connected to a first vertebral body, second cover plate to be connected to the second vertebral body, and a prosthesis core which forms an articulation with the second cover plate. The prosthesis core is held by seat of the first cover plate which is designed as a guide device. The core can be pushed into the guide device from the ventral side in the anterior-posterior (AP) direction relative to the first cover plate. A limit-stop plate is provided on the ventral edge of the first cover plate. This limit-stop plate is displaceable in a slide guide between a locking position and a nonlocking position.

Abstract: An embodiment of an intervertebral prosthetic device for implantation in a spine includes a rigid fixation member and a compressible member. The fixation member is configured to be placed in a cavity of a first vertebral body and against bone of the first vertebral body. The compressible member is configured to be placed in a cavity in an intervertebral disc and to be secured to the first fixation member. Another embodiment includes two compressible members and one fixation member. In this embodiment, the first and second compressible members are sized to substantially replace the nucleus pulposus of first and a second intervertebral discs, respectively, on either side of a vertebral body. The fixation member is sized to fit within a cavity in the vertebral body between the first and second compressible members.

Abstract: An artificial intervertebral disc for implantation between two adjacent vertebrae includes superior and inferior shells connected in a ball and socket arrangement. The inferior shell preferably incorporating a convex portion that cooperates with a concave portion on the superior shell. A resilient nucleus is provided within an enclosure defined by the opposing inner surfaces of the shells and biases the shells against each other. The ball portion can be provided in either fixed or slidable arrangement. The superior and inferior shells are also provided with cooperating male and female portions whereby the shells positively engage each other, thereby preventing separation, but allowing any desired articulation there-between. The artificial disc of the invention includes various resistance means for restricting and limiting the range of rotational and translational motion between the shells.

Abstract: An intervertebral spacer device includes first and second plates disposed in a spaced apart relationship, each plate having an inner surface and an outer surface, the inner surfaces of the opposing plates facing one another. The device also includes a restoring force providing element disposed between the inner surfaces of the plates. The restoring force providing element includes a slotted belleville washer having a convex shape when unloaded and a flatter shape when loaded, whereby one or more slots of the belleville washer widen when compressively loaded. The second plate has an annular groove formed in the inner surface of the second plate, the device including a retaining wall and a retaining ring, whereby a wide end of the belleville washer is captured by the retaining wall and the retaining ring for maintaining the wide end adjacent the inner surface of the second plate.

Abstract: An intervertebral disc prosthesis comprises a first endplate, a second endplate, and a bearing surface positioned between the first endplate and the second endplate. The bearing surface may be provided by a mobile bearing disc including a convex bearing surface configured to engage the first endplate and a concave bearing surface configured to engage the second endplate. The multiple bearing surfaces of the mobile bearing disc engage articulating surfaces on the endplates to form a plurality of articulating joints. Each articulating joint is configured to facilitate a particular type of movement for the segmental unit. Furthermore, each articulating joint is defined by a distinct center of rotation. The contact pair formed by the convex bearing surface of the bearing component and the concave bearing surface of the first endplate may provide a flexion/extension center of rotation for the prosthesis.

Abstract: An artificial disc prosthesis is provided. The prosthesis of the present invention enables spinal segment alignment by having a variable height across its surface. The variable height is achieved by an asymmetric artificial nucleus or by at least one variable height end plate.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces. Each of the opposing plates has an external surface with a deflectable wire mesh thereon, into which the bone can readily grow.

Abstract: Described herein is an intervertebral disk prosthesis with an angled leading edge for insertion into the Intervertebral space. The disk prosthesis may provide for both rotation and compression.

Abstract: An artificial spinal implant for placement between adjacent vertebrae to replace disk material and to stabilize the involved vertebrae is described. The artificial disk may be disassembled for installation and/or removal for repair, replacement or adjustment, and may be assembled from the front of the spine as individual component parts, thereby permitting alignment of the spine during the assembly process, and the stabilization of the involved vertebrae once assembly has been completed. Further, the components may be chosen from a set of similar components having different sizes, thereby enabling the implant to be tailor fit to the requirements of the patient.

Abstract: A total disc implant (TDI) is provided for total replacement of a spinal disc or discs in a human patient or other mammal, wherein the TDI is designed to maintain a substantially full range of natural motion (ROM) following implantation. The TDI generally comprises, in one preferred form, upper and lower end plates for affixation to adjacent vertebral bodies, with an intervening insert disposed therebetween. The end plates each include elongated part-cylindrical surfaces oriented generally perpendicular to each other, with one of said surfaces extending in an anterior-posterior direction and the other extending in a medial-lateral direction. The intervening insert defines concave upper and lower part-cylindrical seats oriented for respectively engaging these part-cylindrical surfaces, wherein these part-cylindrical seats are defined by offset radii to include a somewhat flattened central base region merging smoothly with upwardly curving radiused sides.

Abstract: Articulating diamond-surfaced spinal implants are disclosed. The implants use sintered polycrystalline articulation surfaces which are attached to spinal endplates and which are implanted to replace damaged spinal joints. The implants provide a long wearing and biocompatible articulation surface. Materials which may be used to make the spinal implants and manufacturing and finishing techniques for making the implants are also disclosed.

Abstract: An intervertebral disc prosthesis for the total replacement of a intervertebral disc within the lumbar and cervical spine is disclosed. The intervertebral disc prosthesis comprises articulating sliding partners, wherein the upper sliding partner has means for a firm assembly to an upper vertebral body and the lower sliding partner has means for a firm assembly to a lower vertebral body and at least one sliding surface that is between two sliding partners. Functional two- and three part designs are planned and both prostheses have in common, that only a dorsoventral- and rotation movement is possible as a result of laterolaterally aimed, transversally arched, ventrally curved cylindrical convexity(ies) and corresponding concavity(ies), however without an inclination of the sliding partners in a lateral direction. In a further design, the cylindrical articulation surfaces have no curvature, enabling a motion of the sliding partners in only a ventrodorsal direction.

Abstract: An apparatus and method for supporting upper and lower vertebral bodies, including first and second end members adapted for engagement with the vertebral bodies, and at least one elongate support member coupled between the end members to maintain an axial space between the vertebral bodies. In one aspect of the invention, each of the end members has a parametrical or horseshoe-shaped configuration extending about an open inner region and defining a lateral passage communicating with the open inner region to facilitate insertion of the apparatus or the individual end members into the intervertebral space via a posterior surgical approach. In a further aspect of the invention, a fusion member is positioned within the axial space to promote bony fusion between the upper and lower vertebral bodies.

Abstract: A cervical intervertebral disk prosthesis has two cover plates, at least one of which is provided with a wedge-shaped connection surface for connection to a vertebral body and which is wider than it is deep. The dorsal edge of the connection surface may be set back from the dorsolateral edge of the cover plate having the connection surface and be connected to the dorsal edge, protruding above it, via a rounding or bevel.

Abstract: A problem with total disc implant surgery appears to be the positioning of the implant which if not correct may lead to pain and eventually new surgery. The present invention relates to an improved disc implant (1) for total disc replacement, comprising two inter-vertebral elements (2) which are flexibly connected via coupling means (4,5). Following surgery, the relative movability of said two inter-vertebral elements is decreased overtime, as bone ingrowth occurring around the implant and specifically through osseointegrative sections gradually degrease the movability of the elements relative to each other. Following, the relative movability of the implant elements is replaced by fixation of the elements. The fixation has flowingly occurred in a position affected by the movement of the patient, and is thereby more acceptable to the patient.

Abstract: A method and devices for facilitating fixating and joining of bone fractures utilizing expandable devices that are positioned within the bone and across the fracture site. The stress from the expanded may enhance and expedite bone healing.

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 intersomatic implant (1a, 1b) maintains bone graft material in a receiving cavity formed in a disc in order to obtain intervertebral fusion. The implant (1a, 1b) includes of a plurality of parts provided with means for in situ connection of two consecutive parts. Instruments (33) are used to connect these implants (1a, 1b) and a tool assists in introducing these implants (1a, 1b) into the cavity formed in the disc.