A surgical tool for use in spinal stabilization for fusing contiguous vertebra in an animal spine. The tool includes a distal end having external dimensions sized for the distal end to be inserted within the animal body and located against a tissue layer between contiguous vertebra. Cutting blades are carried on the distal end for cutting at least a portion of the layer and at least a portion of vertebra bodies to form a chamber within the contiguous vertebra. The cutting blades are selected for the chamber to be sized greater than the external dimensions of the distal end. A control element is provided for controlling a depth of cut of the cutting blade between at least first and second positions with the cutting blade retained within the external dimensions when in the first position and with the cutting blade extended to form the chamber when in the second position.