INTERVERTEBRAL. PROSTHESIS ENDPLATE HAVING DOUBLE DOME AND SURGICAL TOOLS FOR PREPARING THE VERTEBRAL BODY ENDPLATE TO RECEIVE THE PROSTHESIS

摘要

An endplate for an intervertebral prosthesis includes : a generally- planar base plate (162 ), a f irst elevated region ( 152 ), or dome, within the base plate periphery, and a second elevated region ( 153 ), or dome, within the boundary (164 ) of the f irst elevated region. The antero-posterior and side-to-side (medial-lateral ) dimensions of the f irst elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the f irst elevated region are def ined 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 (201 ) for preparing a surgical site for implantation of the prosthesis has a rasp head (202 ) having a pivot point and rasp teeth (224 ) arranged to produce a recess or seat of predetermined shape. A groove-cutter (300 ) 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 ( 301 ) that can be stowed in a recess while the cutter is initially positioned within the intervertebral space.