An endplate for an intervertebral prosthesis prosthesis endplate of the invention 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 for preparing a surgical site for implantation of the prosthesis has a rasp head having a pivot point and rasp teeth arranged to produce a recess or seat of predetermined shape. A groove-cutter for preparing a medial antero-posterior groove in a vertebral body without damaging the anterior rim of the vertebral body has a guide head that is seated in a prepared recess in the vertebral body and a reciprocable tooth that can be stowed in a recess while the cutter is initially positioned within the intervertebral space.