Abstract: Presented is a method and instrumentation for removal of a pair of rectangular blocks of vertebral bone tissue of predetermined and precise dimensions to provide an intervertebral recess, with guarded depth for safety, achieving and maintaining the desired intervertebral space, as well as obtaining and injecting into the intervertebral recess a well-fitted bone plug of the same dimension as the recess that receives it. Two cooperating instruments are utilized in the invention, one being an intervertebral mortising cutter and the other a precision guide and spacer. The guide and spacer functions dually to retain the associated adjacent vertebrae at a precise selected and predetermined spacing and to guide penetration of the mortising cutter. Following advancement of the mortising cutter into the bone tissue of the two adjacent vertebrae, the instruments, along with the blocks of bone tissue, are removed from the site to produce a precisely configured recess.