Systems and methods for robotically distracting a disc space are provided for implantation of an intervertebral prosthetic disc. The system includes a 3D modeling system for creating a 3D model of first and second vertebra adjacent the disc space and identifying positions of the first and second vertebrae. A robotic distractor precisely opens the disc space just large enough to receive a selected intervertebral disc. A computing system stores and processes the 3D model and the positions of the first and second vertebrae before and after distraction. A surgeon interface on the computing system allows the surgeon to select an intervertebral disc prosthesis to be implanted and a desired distraction distance or force to be achieved.