Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. The preferred spring mechanism is at least one belleville washer having radially spaced concentric grooves. In a preferred embodiment there is a single such belleville washer which is modified to mount onto a ball-shaped head. The lower plate of this embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The modified belleville washer can be rotatably mounted to the head such that the wider portion of the washer seats against the upper plate.

Abstract: Instrumentation for implanting a cervical disc replacement device includes cervical disc replacement trials for determining the appropriate size of replacement device to be implanted, an insertion plate for maintaining the elements of the replacement device in fixed relation to one another for simultaneous manipulation, an insertion handle for attachment to the insertion plate for manipulation of the elements, an insertion pusher for releasing the insertion handle from the insertion plate, a drill guide that cooperates with the insertion plate to guide the drilling of tap holes for bone screws to be placed through bone screw holes in the flanges of the replacement device, clips that are applied to the flanges after placement of the bone screws to resist screw backout, and a clip applicator for applying the clips to the flanges.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by a spring mechanism. The preferred spring mechanism is a domed arched strip spring which is coupled to the upper plate by set screws. The spring includes a socket formed in the peak thereof and mounts onto a ball-shaped head extending outwardly from the lower plate. The spring and post members are thereby flexibly coupled such that the upper and lower plates may rotate relative to one another.

Abstract: An apparatus for testing an implant having first and second components coupled together by an articulating ball and socket joint includes a support structure in contact with the first component of the implant for supporting said implant, an adapter coupled to the second component of the implant, and a load assembly in contact with the adapter for applying a load onto a semispherical surface of the adapter. The apparatus includes a drive assembly coupled with the adapter having a first drive shaft having a first end connected with a center of a rotatable wheel and a second drive shaft having a first end connected with an outer region of the wheel and a second end connected to the adapter. The second drive shaft has a longitudinal axis that is at an angle relative to the longitudinal axis of the first drive shaft.

Abstract: A machine for testing components of a joint in relative articulation under a load includes an adapter fixed to a movable joint component and having a semispherical upper surface concentric with a semispherical articulation surface of the movable component, a load assembly configured in load applying relation to the semispherical upper surface and having a load adapter providing a lower semispherical surface against which the adapter can articulate under the load, and a drive assembly configured in articulating driving relation with the adapter and having a rotatable wheel and a drive shaft mechanically coupled thereto in angular offset relation to the wheel's rotation axis. Rotating the wheel effects an articulation of the adapter under the load and in turn an articulation of the movable component under the load against a semispherical pocket of a stationary joint component, in an articulation pattern determined by the angular offset relationship.

Abstract: A porous intervertebral spacer having a flexible wire mesh as a vertebral body contact surface, the flexible wire mesh preferably being a convex titanium mesh laser-welded at its perimeter to the spacer. The mesh is domed in its initial undeflected conformation, but deflects as necessary during insertion of the spacer between vertebral bodies, and, once the spacer is seated between the vertebral bodies, deforms as necessary under anatomical loads to reshape itself to the concave surface of the vertebral endplate, providing gripping and holding strength upon initial implantation, and an osteoinductive surface through which the bone may ultimately grow, making the fixation of the spacer between the vertebral bodies secure.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. The preferred spring mechanism is at least one spirally slotted belleville washer having radially spaced concentric grooves. In a preferred embodiment there is a single such belleville washer which is modified to mount onto a ball-shaped head. The lower plate of this embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The modified belleville washer can be rotatably mounted to the head such that the wider portion of the washer seats against the upper plate.

Abstract: A surgical treatment for restoring a proper anatomical spacing and alignment to vertebral bones of a scoliosis patient, the treatment including determining an angular misalignment associated with at least one pair of adjacent bones, adjusting the intervertebral space between adjacent vertebral bones to restore proper spacing, and inserting a tapered spacer to restore proper anatomical misalignment of the vertebral bones.

Abstract: An intervertebral spacer has curvate upper and lower rough surfaces that stimulate bone growth and is formed from a porous material that facilitates bone growth thereinto. The spacer has a plurality of smooth linear grooves to facilitate insertion of the spacer into an intervertebral space using a spacer insertion tool that has a scissor-style body. Each of the insertion tool's arm's heads has an inner surface having a pair of smoothed linear protrusions that fit within the linear grooves of the spacer when the heads are closed about the spacer. When the spacer is held, spaces are present between the spacer's rough surfaces and the heads' inner surfaces so that when the protrusions are longitudinally slid from the grooves to leave the spacer in the intervertebral spacer, the rough surfaces are not disturbed.

Abstract: An intervertebral spacer having opposing plates seatable against opposing vertebral bones, separated by at least one spring mechanism, preferably a spirally slotted belleville washer having a wide end rigidly fixed to an upper plate and a narrow end rotatably mounted to a lower plate. The lower plate includes an inwardly deflecting central post extending upwardly from the inner surface of the lower plate, the post including a head that is received through a central opening in the narrow end of the washer so that the washer is restricted from angulation with respect to the lower plate, but allowed to rotate with respect to the lower plate so that the plates can rotate relative to one another. The plates can angulate relative to one another because the washer deflects under lateral deflection forces and return to its undeflected shape when the forces are relieved.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one force restoring element. The preferred force restoring mechanism is a wave washer. In a first embodiment the wave washer is ring-shaped. In a second embodiment the wave washer is spiral-shaped.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. A first plate of this embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The post is designed to flexibly support a slotted belleville washer, which can be selectively mounted to the head such that the wider portion of the washer seats against the second plate. Compression of the assembly causes a deflection of the slotted belleville washer. The slotted belleville washer of this invention has a radially varying thickness which permits the load deflection profile to mimic that of the natural cartilage which is being replaced.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. The preferred spring mechanism is an arched strip spring. In a first embodiment there are multiple springs positioned independently about the area of the opposing plates. In a second embodiment there is a single arched strip spring modified to mount onto a ball-shaped head. The lower plate of this second embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The spring and post members are flexibly coupled such that the upper and lower plates may rotate relative to one another.

Abstract: An intervertebral distraction tool has a clamshell head with upper and lower halves, each having a curvate outer surface and a flat inner surface. The distal side of the head is hinged so that the head opens and closes from the proximal side of the head. The hinge is a separating hinge that allows the halves to not only angulate with respect to one another about the hinge axis, but also to vertically separate from one another at the hinge. A distraction separator has decreasing taper at its distal end and a longitudinal bore that accommodates the elongate shaft of the trial so that the separator can be moved longitudinally relative to the shaft. Upon forward movement of the separator, the tapered upper and lower surfaces engage the flat inner surfaces of the head, causing the halves to angulate about the hinge axis of the head, thereby opening the head.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by a spring mechanism. The preferred spring mechanism is a slotted domed arch strip spring which is coupled to the upper plate by set screws. The spring includes a socket formed in the peak thereof and mounts onto a ball-shaped head extending outwardly from the lower plate. The spring and post members are thereby flexibly coupled such that the upper and lower plates may rotate relative to one another.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. The preferred spring mechanism is at least one spirally slotted belleville washer having radially extending grooves. In a preferred embodiment there is a single such belleville washer which is modified to mount onto a ball-shaped head. The lower plate of this embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The modified belleville washer can be rotatably mounted to the head such that the wider portion of the washer seats against the upper plate.

Abstract: An instrument for inserting an implant between vertebral bodies, including a holder adapted to hold the implant during insertion of the implant between the vertebral bodies, a retractor adapted to retract the holder away from the implant after the insertion, and a guard adapted to prevent the implant from being removed from between the vertebral bodies during the retraction.

Abstract: An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by a spring mechanism. The preferred spring mechanism is a multi-pronged domed spring which is coupled to the upper plate by set screws. The spring includes a socket formed in the peak thereof and mounts onto a ball-shaped head extending outwardly from the lower plate. The spring and post members are thereby flexibly coupled such that the upper and lower plates may rotate relative to one another.

Abstract: A gravity dependent pedicle screw tap hole guide comprises a guide shaft maintainable parallel to a drill bit during the drilling of a pedicle screw tap hole; a level indicator associated with a reference direction and responsive to gravity to provide feedback regarding an angular difference between an acting direction of gravity and the reference direction; and a mounting attaching the indicator to the shaft and establishing a positional relationship between the reference direction and the longitudinal axis. Using the guide involves angulating the shaft about its distal end adjacent the base of the superior articular process and the base and middle of the transverse process until the guide indicates that the angular orientation of the longitudinal axis matches the previously determined pedicle axis orientation with respect to the acting direction of gravity, and then drilling the tap hole along a trajectory established by the longitudinal axis of the shaft.

Abstract: An intervertebral space distraction and implantable device assembly provides sequentially axially wider spacers that are to be sequentially inserted into and removed from an intervertebral space to widen the space until a desired anatomical spacing of the adjacent vertebral bones is restored. The set of spacers includes a porous spacer that is as wide as the spacer that restores the desired anatomical spacing. The porous spacer can therefore be left implanted in the intervertebral space to promote fusion of the adjacent vertebral bones.