Abstract: An endplate for an intervertebral prosthesis includes a generally planar base plate, a first elevated region, or dome, within the base plate periphery, and a second elevated region, or dome, within the boundary of the first elevated region. The antero-posterior and side-to-side (medial-lateral) dimensions of the first elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the first elevated region are defined by arcs that terminate in sagittal planes of the endplate, and are symmetrical with respect to a coronal plane of the endplate. A bone rasp and a groove cutter for use in implanting the prosthesis are also provided.

Abstract: An endplate for an intervertebral prosthesis includes an inner domed region and a peripheral rim wherein the inner domed region has a non-circular plan and has an area that is at least 50% of the area of the endplate. A surgical instrument for milling a recess in a vertebral endplate includes a cutting tool having a drive shaft with a positioning collar, a guard frame, and a pair of guide plates attached to the guard frame and spaced to confine the positioning collar and having guide slots for the drive shaft.

Abstract: An endplate for an intervertebral disc prosthesis includes: a baseplate, sized and configured to fit within at least a portion of an intervertebral space, and an anterior portion having an outer vertebra-contacting surface extending outwardly from the baseplate at an acute angle with respect to an axis of the baseplate, and being provided with an opening configured to receive a fastener.

Abstract: An endplate for an intervertebral prosthesis includes a generally planar base plate, a first elevated region, or dome, within the base plate periphery, and a second elevated region, or dome, within the boundary of the first elevated region. The antero-posterior and side-to-side (medial-lateral) dimensions of the first elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the first elevated region are defined by arcs that terminate in sagittal planes of the endplate, and are symmetrical with respect to a coronal plane of the endplate. A bone rasp and a groove cutter for use in implanting the prosthesis are also provided.

Abstract: An endplate for an intervertebral prosthesis includes a generally planar base plate, a first elevated region, or dome, within the base plate periphery, and a second elevated region, or dome, within the boundary of the first elevated region. The antero-posterior and side-to-side (medial-lateral) dimensions of the first elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the first elevated region are defined by arcs that terminate in sagittal planes of the endplate, and are symmetrical with respect to a coronal plane of the endplate. A bone rasp and a groove cutter for use in implanting the prosthesis are also provided.

Abstract: An endplate for an intervertebral prosthesis includes an inner domed region and a peripheral rim wherein the inner domed region has a non-circular plan and has an area that is at least 50% of the area of the endplate. A surgical instrument for milling a recess in a vertebral endplate includes a cutting tool having a drive shaft with a positioning collar, a guard frame, and a pair of guide plates attached to the guard frame and spaced to confine the positioning collar and having guide slots for the drive shaft.

Abstract: A surgical implant, especially an artificial intervertebral disc, includes a rigid substrate (513) having a porous attachment structure (512) that covers a portion of the substrate and an elastomeric body (510) that is fastened to the substrate by impregnating the porous attachment structure. The porous attachment structure has a net porosity greater than 21.5%. The porous attachment structure may be, for example, a perforated plate or a screen spaced from a substrate surface, or a layer of trabecular metal or an open-cellular material.

Abstract: An endplate for an intervertebral prosthesis includes an inner domed region (330) and a peripheral rim (332) wherein the inner domed region has a non-circular plan and has an area that is at least 50% of the area of the endplate. A surgical instrument for milling a recess in a vertebral endplate includes a cutting tool having a drive shaft with a positioning collar, a guard frame, and a pair of guide plates attached to the guard frame and space to confine the positioning collar and having guide slots for the drive shaft.

Abstract: An intervertebral disc and facet joints prosthesis includes (i) an intervertebral disc prosthesis element having an upper rigid prosthesis endplate, a lower rigid prosthesis endplate, and a core interposed between and attached to the rigid endplates, and (ii) at least one facet joint prosthesis element, each facet joint prosthesis element including an upper facet joint prosthesis component and a lower facet joint prosthesis component. The upper facet joint prosthesis component is constructed to cooperate with its respective lower facet joint prosthesis component, the upper facet joint prosthesis component being rigidly fixed to the upper endplate and the lower facet joint prosthesis component being rigidly fixed to the lower endplate. The prosthesis may be implanted by surgical procedures involving a posterior or postero-lateral approach.

Abstract: A prosthetic implant for replacing a facet joint of a spinal motion segment includes a generally conical superior component adapted to be implanted at a surgically prepared site on a lower articular process of a cephalad vertebra of a spinal motion segment, and a cup-shaped inferior component adapted to be implanted at a surgically prepared site on a superior articular process of a caudad vertebra of the spinal motion segment.

Abstract: In an intervertebral disc prostheses having a pair of rigid endplates and an elastomeric core structure between the endplates. The core structure is designed to provide desired functional characteristics of the prosthesis.

Abstract: An endplate for an intervertebral prosthesis includes an inner domed region (330) and a peripheral rim (332) wherein the inner domed region has a non-circular plan and has an area that is at least 50% of the area of the endplate. A surgical instrument for milling a recess in a vertebral endplate includes a cutting tool having a drive shaft with a positioning collar, a guard frame, and a pair of guide plates attached to the guard frame and space to confine the positioning collar and having guide slots for the drive shaft.

Abstract: A prosthetic implant for replacing a facet joint of a spinal motion segment includes a generally conical superior component adapted to be implanted at a surgically prepared site on a lower articular process of a cephalad vertebra of a spinal motion segment, and a cup-shaped inferior component adapted to be implanted at a surgically prepared site on a superior articular process of a caudad vertebra of the spinal motion segment.

Abstract: A prosthetic implant for replacing a facet joint of a spinal motion segment includes a generally conical superior component adapted to be implanted at a surgically prepared site on a lower articular process of a cephalad vertebra of a spinal motion segment, and a cup-shaped inferior component adapted to be implanted at a surgically prepared site on a superior articular process of a caudad vertebra of the spinal motion segment.

Abstract: An intervertebral disc prosthesis includes upper and lower rigid endplates and an elastomeric core structure located between the endplates and attached thereto, wherein the elastomeric core structure has a centroid positioned posterior to a centroid of at least one of the endplates.

Abstract: A surgical implant, especially an artificial intervertebral disc, includes a rigid substrate (513) having a porous attachment structure (512) that covers a portion of the substrate and an elastomeric body (510) that is fastened to the substrate by impregnating the porous attachment structure. The porous attachment structure has a net porosity greater than 21.5%. The porous attachment structure may be, for example, a perforated plate or a screen spaced from a substrate surface, or a layer of trabecular metal or an open-cellular material.

Abstract: and methods for attaching an implant to bone are disclosed. In one embodiment, the device 10 includes an elongated stud 15 defining an engaging surface 16 and a foot 20 projecting outwardly from an end 18 of the stud 15. The foot 20 is receivable through an opening O in the cortical layer R of the bone B and includes an upper surface 21 for contacting an internal surface R' of the cortical layer R. A fastener 25 is provided for engaging the engaging surface 16 of the stud 15, having a surface 29 for bearing against the implant I to clamp the implant I to the bone B when the fastener 25 is engaged to the engaging surface 16 of the stud 15 and the foot 20 is received in the opening O. In another embodiment, the apparatus 30 includes a number of additional studs 31 which are extendable together through the opening O. A wedge 36 can be provided to clamp the multiple studs within the bone opening.

Abstract: The construction and manufacturing technique for a functional biocompatible intervertebral disc spacer is described. This device is useful for a replacement for a degenerated disc in certain treatments of back pain and spinal disease. The disc spacer possesses mechanical properties akin to those of the normal disc and will preserve normal functions of the spinal motion segment. The device achieves the desired properties by varying the hardness of the elastomeric material in its nucleus and annulus.

Abstract: A spinal fixation system is provided with pedicle clamps having multiple hooks for engagement with selected portions of a patient's vertebrae. The pedicle clamp includes three hooks which may be slidably positioned relative to each other to securely engage exterior surfaces of the lamina. A surgical tool is also provided to securely position the hooks with respect to each other on the exterior of the lamina. The surgical tool includes a fork for engaging the movable hooks of the pedicle clamp and a wrench for locking the movable hooks relative to each other and the pedicle clamp.

Abstract: The construction and manufacturing technique for a functional biocompatible intervertebral disc spacer is described. This device is useful for a replacement for a degenerated disc in certain treatments of back pain and spinal disease. The disc spacer possesses mechanical properties skin to those of the normal disc and will preserve normal functions of the spinal motion segment. The device achieves the desired properties by varying the hardness of the elastomeric material in its nucleus and annulus.