Intervertebral prosthesis endplate having double dome and surgical tools for implanting same

An endplate for an intervertebral disc prosthesis, comprising:

• a base plate having a periphery sized and configured to fit within an intervertebral space of a human spinal motion segment;
• a first elevated region within said periphery having an antero-posterior dimension and a transverse dimension different from said antero-posterior dimension and being bounded by a wall spaced generally radially inward from said periphery
• said wall having laterally opposite side portions defined by circular arcs each of said circular arcs having a center located on a sagittal plane of said base plate;
• and
• a second, generally dome-shaped, elevated region within said first elevated region, said second elevated region having laterally opposite side portions defined by circular arcs having a common center located in said median plane.

An intervertebral prosthesis for implantation in an intervertebral space of a spinal motion segment, comprising:

• an elastomeric core sized and configured to fit within said intervertebral space and having upper and lower surfaces, and
• a pair of endplates fastened to respective said upper and lower surfaces of said elastomeric core, said endplates being adapted to contact vertebral endplates of adjacent vertebrae,
• at least one of said endplates comprising:
• a base plate having a periphery sized and configured to fit within an intervertebral space of a human spinal motion segment;
• a first elevated region within said periphery having an antero-posterior dimension and a transverse dimension different from said antero-posterior dimension and being bounded by a wall spaced generally radially inward from said periphery
• said wall having laterally opposite side portions defined by arcs terminating in sagittal planes of said base plate and symmetrical with respect to a coronal plane of said base plate;
• and
• a second, generally dome-shaped, elevated region within said first elevated region, said second elevated region having laterally opposite side portions defined by circular arcs having a common center located in said median plane.

An intervertebral prosthesis for implantation in an intervertebral space of a spinal motion segment, comprising:

• an elastomeric core sized and configured to fit within said intervertebral space and having upper and lower surfaces, and
• a pair of endplates fastened to respective said upper and lower surfaces of said elastomeric core, said endplates being adapted to contact vertebral endplates of adjacent vertebrae,
• at least one of said endplates comprising:
• a base plate having a periphery sized and configured to fit within an intervertebral space of a human spinal motion segment;
• a first elevated region within said periphery having an antero-posterior dimension and a transverse dimension different from said antero-posterior dimension and being bounded by a wall spaced generally radially inward from said periphery
• said wall having laterally opposite side portions defined by circular arcs each of said circular arcs having a center located on a sagittal plane of said base plate and being symmetrical with respect to a coronal plane of said base plate;
• and
• a second, generally dome-shaped, elevated region within said first elevated region, said second elevated region having laterally opposite side portions defined by circular arcs having a common center located in said median plane.

A bone rasp apparatus configured to form a recess of predetermined configuration in a vertebral body, comprising

• at least one bone rasp tool including:
• a rasp head, and
• a handle,
• said rasp head having:
• a pivot member, and
• rasp teeth arranged to prepare at least a portion of said recess by reciprocal pivotal rotation of said rasp head about said pivot member.