Abstract: The invention provides a rod assembly for implantation into the spine which includes a bone anchor assembly providing two points of angulation for the connection between the point of fixation and the rod. Further, the distance of offset between the point of fixation and the rod can be varied. The invention uses a bone screw having a pronged cage with a recess that accommodates the head of a post member. The cage can be tightened around the head by the camming surfaces of a locking cap that is drawn down around the compressible cage as the head is screwed upward in the recess by the engagement of the threads of the post by a locking nut. Further, the locking cap has a slotted bushing that is positionable in the elongated slot of a rod connector member. The locking nut includes an external taper that expands the bushing outward to lock it into position in the slot.

Abstract: A vertebral cage is provided for use in preserving the space between adjacent vertebral during the process of spinal fusion. In particular, this cage has an open modified oval peripheral shape with a continuous fluid anterior wall having angled screw passages accessible through co-planar openings to allow the construct to be stabilized between adjacent vertebral bodies through their endwalls. In addition, the cage has a back to front wedge taper with pull-out resistant ratchet surfaces. Further, in a second aspect of the invention, the screw passages have a unique locking mechanism provided by oversized internal threads in combination with a second locking thread on the head of the associated bone screws that allows for axial translation of the screws within the screw passages. This in turn permits play in the angulation of the screw relative to the anchoring bone in order to optimize the screw placement in the bone.

Abstract: A prosthetic nucleus replacement embodiment of the present invention comprises a rounded shaped ceramic domed body with a receptacle in its bottom side. A keeled base of biocompatible metal is press-fit into the receptacle at any relative angle to complete a two-piece assembly. A keel part of the base especially is finished in porous coated metal and shaped to promote natural in-growth of bone from the inferior vertebrae.

Abstract: The invention provides a bone screw for use in an implant assembly having a member including a hole through which the screw extends. The member preferably includes a socket in an anchor that receives a rounded bottom portion of the screw head in order to form a ball and socket connection. The screw has a necked area below the rounded bottom portion which projects through the hole and below that on the longitudinal axis of the screw. The screw includes a knurled collar that is sized so as to allow the anchor to be inserted onto the screw but which subsequently restrains the anchor from falling downward onto the threaded area of the screw.

Abstract: The present invention provides a fastener, such as a screw or nut and tool designed in particular for use with an orthopedic implant system wherein the fastener has a multi-lobed torque driving recess. The recess has a central area bounded by equally spaced hemicircular grooves separated by internally projecting land having two sharp edges. The tool has a corresponding male shape, which in conjugation with the recess, is designed to achieve a controlled torque load with a minimized possibility of stripping the recess or of shearing the torque-driving tip from the tool.

Abstract: A prosthetic nucleus replacement embodiment of the present invention comprises a rounded shaped ceramic domed body with a receptacle in its bottom side. A keeled base of biocompatible metal is press-fit into the receptacle at any relative angle to complete a two-piece assembly. A keel part of the base especially is finished in porous coated metal and shaped to promote natural in-growth of bone from the inferior vertebrae.

Abstract: The present invention relates to a transverse connector having an assembly, which joins two spinal rods to form a spinal implant construct. The transverse connector has two members each having terminal clamping members such as opposing rod recesses each having a biasing setscrew, which locks the rod into position in the recess. The first of the two members has a bore, which receives the cylindrical extension of the other part so that it can move inward and outward and rotate in the bore. Further, the connector has a limiting mechanism, which comprises a vertical keyway which receives and captures the flanged end of the extension in a slot having opposed undercut areas so that the flanged end can be inserted into the keyway and slid downward toward the bore. The extension further has a second flanged area in order to avoid over-insertion of the second member into the first member.

Abstract: A bone plate assembly is provided having a fixation plate held in position in a bone by a plurality of fasteners. The fasteners extend through holes in the bone plate to engage the bone below. Further, the assembly includes a locking plate, which is secured to the fixation plate by a lock screw or in a further embodiment by a mechanically biased detent extending into a hole in the locking plate. The lock plate can also include a divot, which is shallower than the hole to hold the lock plate in a open position. Further, the locking plate has a dovetailed connection to engage the flanges defining the exterior edges of a channel and the fixation plate. The locking plate, thus, has a sliding connection from a first position where it has at least partial openings corresponding to the openings of the fixation plate for the fasteners, and optionally also for a graft screw.

Abstract: A spinal implant system is provided having a stabilization rod, a plurality of bone anchors which could be either hooks or screws and which have an internal recess that defines a rod-receiving channel. Sidewalls of the anchor project beyond the recess, and are threaded on the outside. These external threads cooperate with the internal threads of a locking member, or cap nut, which has a top surface with a cavity that includes an internal hexagon. The internal threads are on the inside of the cylindrical sidewalls of the cap nut. Further, on the bottom side of the top surface, the cap nut has a guide member in the form of a cylindrical boss, which has a smaller diameter than that of the recess within the anchor. The boss helps to prevent cross threading and to prevent collapse of the anchor sidewalls under high forces. An annular ridge on the bottom of the boss further helps to retain the rod relative to the anchor.

Abstract: The invention relates to a bone plate having at least two and up to ten rimmed eyelets for receiving anchoring bone screws in a modified ball-and-socket joint. The eyelets are longitudinally aligned and joined to neighboring eyelets by curvilinear, bendable ribs extending between pairs of eyelets. The ribs are of a longer length than the distance between the external surfaces of adjacent rings which allows the longitudinal spacing of the rings to be increased or decreased by bending the ribs.

Abstract: The invention relates to a set screw having a self-limiting external torque head. The head has a hexagonal external cross-section and an internal bore which extends through a necked portion. The necked portion joins the external torque head to the threaded screw portion of the set screw. The necked portion has a cross-sectional thickness and strength to provide for shearing at a predetermined load limit, such as from about 54 to about 64 pounds per inch. The threaded screw portion has an internal hex to allow for the internal application of loosening torque at about two-thirds of the tightening torque limit, i.e., to provide a loosening torque of about 40 inch-pounds. The screw member includes a high-compression, rod-contacting surface such as a knurled surface.

Abstract: This invention relates to a transverse connector member which is used to connect two substantially parallel spinal implant rods. The transverse connector has a first and a second member which includes a clamp comprising a rod receiving recess and top-loaded set screw which cause both a vertical and a horizontal loading of the rod in order to bias the rod into contact with the recess. The set screw is a beveled set screw. In one embodiment, the clamping members are two separate components which provide for an adjustable distance between the clamping members. In another embodiment, the connector is a single unit in which the clamping members have openings in the same direction to facilitate loading the connector onto the rods.

Abstract: A spinal implant assembly is provided having a top loading anchor which is fixed to a spinal member by means of a hook or screw. The anchor includes a seat having a channel to receive a stabilizer rod and a sliding interconnecting closure member which slides in a longitudinal direction relative to the anchor seat to form an integral closed anchor seat assembly. The closure member includes retaining flanges which dove tail relative to undercut retaining flanges of the seat member so as to prohibit the sliding closure member from being dislodged from the closure from the seat channel, as well as inhibit the splaying of the seat member in response to forces which may be imposed upon the seat member during derotation of the spine. In addition, the seat member includes a boss and/or hollow to form a biased lock and compression screw to lock the rod in position relative to the anchor. An instrument is provided which holds the slide for assembly in a spring loaded ball plunger.

Abstract: An apparatus is provided for the internal fixation of the spine. The apparatus comprises an assembly having at least two anchors and an elongated stabilizer. The anchors each have means to hold the anchor to the bone, and include receiving means which receive the stabilizer as well as securing means which cooperate with the receiving means by means of the interaction of mating threads to cause the application of compression on the stabilizer into the receiving means.

Abstract: A bone interface anchor is provided for use with a stabilizer rod for the internal fixation of a spine. The anchor has a seat which accommodates the stabilizer rod and which receives a bone screw for the fixation of the seat to the bone. A compression member cooperates with the seat external to the stabilizer rod and can be tightened to cause a compressive force on the stabilizer rod. The stabilizer rod bears on a rounded surface of the bone screw so as to cause a mating interface between the seat and the bone screw. Subsequently, the position of the seat relative to the bone screw can be locked.

Abstract: An apparatus is provided for the internal fixation of the spine. The apparatus comprises two sets of implants (8) each consisting of a rod (18) and a plurality of vertebral anchors (16). The rod (18) is secured to the vertebral elements by the vertebral anchors (16). The anchor (16) includes a transpedicular screw (21) which is secured to a vertebrae. The anchor (16) further includes an anchor seat (23) which captures the screw (21) and permits micromotion between the anchor seat (23) and screw (21). This seat (23) has a rod-receiving channel (51,52) which captures the rod (18). A cap (25) cooperates with the seat (23) to secure the rod (18) in the anchor (16). A nut (27) screws down from the top of the assembly onto the seat (23) to cause rod (18) receiving flanges (46,47) in the cap (23) to apply a compressive force to the rod (18 ). A method of therapy is presented in which the present implants (8) are inserted surgically into a patient.