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 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: A prosthesis for replacing or supplementing a nucleus pulposus of an intervertebral disk is an expandable container having flexible walls, the container being adapted to be inserted into a central cavity of an intervertebral disk through a narrow cannula, and the flexible walls are made from a biocompatible hydrogel. A preferred hydrogel is a cryogel formed from an aqueous solution of poly(vinyl alcohol) and poly(vinyl pyrrolidone). The prosthesis may be prepared by dip-coating a mandrel with an aqueous solution of a hydrogel-forming polymer or mixture of such polymers, gelling the coated solution by chilling, and subjecting the gelled coating to a series of repeated freeze-thaw treatments. In use, the prosthesis is inserted into a central cavity of an intervertebral disk and filled with biocompatible material, e.g., a biocompatible liquid, a biocompatible polymer, and a biocompatible hydrogel, particularly a thermogelling hydrogel.

Abstract: A nucleus pulposus of an intervertebral disc is supplemented or replaced by a physiologically fully hydrated solid hydrogel intervertebral body comprising a polyvinyl alcohol copolymer, wherein the solid hydrogel intervertebral body exhibits an osmotic pressure of from 0.1 to 0.3 megapascals prior to insertion into a patient, the solid hydrogel intervertebral body having a ratio of length to principal transverse dimension not less than about 5:1.

Abstract: A nucleus pulposus of an intervertebral disc is supplemented or replaced by an elongated, physiologically fully hydrated hydrogel prosthesis inserted into the central region of an intervertebral disc, where it can fold upon itself to form a prosthesis body within the central region of the annulus fibrosus. The hydrogel prosthesis may have expanded portions that assist in preventing expulsion of the prosthesis through the insertion aperture. An instrument for inserting the prosthesis has a cutter for severing the elongated prosthesis within the central region of the intervertebral disc after a sufficient amount has been implanted.

Abstract: A femoral component (100) for a total knee joint replacement has a modular structure including a number of segments (102, 112), each of the segments (102, 112) having a femoral fixation surface (104, 114) for attachment to the distal end of a femur and at least one assembly surface (108) for joining with an adjacent segment (102, 112) of the modular femoral component (100). The assembly surfaces (108) are generally planar and arranged to be oriented generally in a plane extending in a proximal-distal direction and in an anterior-posterior direction when the femoral fixation surface (104, 114) is positioned on the distal end of the femur. Although the assembly surfaces (108) are generally planar, they may be shaped or provided with complementary structures (120) to assure self-alignment when the segments (102, 112) are assembled.

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: Thermogelling polymers are described containing poly (n-isopropyl acrylamide). Solutions of this polymer, copolymers or mixtures of the polymer with a second polymer such as poly(ethylene glycol), poly (vinyl pyrrolidone) or poly(vinyl alcohol) are liquids at room temperature and solids at body temperature. Thus, also provided are methods of implanting a hydrogel into a mammal by injecting the solution as a liquid at a temperature below body temperature into a selected site in the mammal at a temperature below body temperature, which then undergoes thermal phase transition to form a solid hydrogel in situ in the body as the implant warms to body temperature. Methods for using these thermal gelling materials in various applications including nucleus pulposus replacement/augmentation, wound care, disk replacement, cartilage replacement, joint replacement, surgical barriers, gastrointestinal devices, cosmetic and reconstructive surgery, and breast enlargement are also provided.

Abstract: A prosthesis for replacing or supplementing a nucleus pulposus of an intervertebral disk is an expandable container having flexible walls, the container being adapted to be inserted into a central cavity of an intervertebral disk through a narrow cannula, and the flexible walls are made from a biocompatible hydrogel. A preferred hydrogel is a cryogel formed from an aqueous solution of poly(vinyl alcohol) and poly(vinyl pyrrolidone). The prosthesis may be prepared by dip-coating a mandrel with an aqueous solution of a hydrogel-forming polymer or mixture of such polymers, gelling the coated solution by chilling, and subjecting the gelled coating to a series of repeated freeze-thaw treatments. In use, the prosthesis is inserted into a central cavity of an intervertebral disk and filled with biocompatible material, e.g., a biocompatible liquid, a biocompatible polymer, and a biocompatible hydrogel, particularly a thermogelling hydrogel.

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 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: Thermogelling polymers are described containing poly (n-isopropyl acrylamide). Solutions of this polymer, copolymers or mixtures of the polymer with a second polymer such as poly(ethylene glycol), poly (vinyl pyrrolidone) or poly(vinyl alcohol) are liquids at room temperature and solids at body temperature. Thus, also provided are methods of implanting a hydrogel into a mammal by injecting the solution as a liquid at a temperature below body temperature into a selected site in the mammal at a temperature below body temperature, which then undergoes thermal phase transition to form a solid hydrogel in situ in the body as the implant warms to body temperature. Methods for using these thermal gelling materials in various applications including nucleus pulposus replacement/augmentation, wound care, disk replacement, cartilage replacement, joint replacement, surgical barriers, gastrointestinal devices, cosmetic and reconstructive surgery, and breast enlargement are also provided.

Abstract: A bone pin made with a tapered polymeric portion and a cutting device secured to the smaller end of the polymeric portion. The pin can be inserted through a bone or bone fragment and the cutting device removed.

Abstract: A bone pin made with a tapered polymeric portion and a cutting device secured to the smaller end of the polymeric portion. The pin can be inserted through a bone or bone fragment and the cutting device removed.