An instrument, instrument system and method for cutting a cutout in a vertebral bone adjacent an intervertebral space are provided which make use of a cutting blade. The cutting blade is mounted on a support structure for movement toward and cutting into the vertebral bone. A stop arrangement is also mounted on the support structure and is movable relative to the cutting blade to a position to limit movement of the cutting blade into the vertebral bone. Typically, the limited movement cutting is made after two cutouts are provided in adjacent vertebral bones using a trial implant.