A system for drilling a bore in adjacent vertebrae to facilitate the insertion of a fusion implant includes a surgical retractor having a sleeve member with proximal and distal end portions and defining a longitudinal opening and a drill instrument positionable within the longitudinal opening of the surgical retractor. The retractor is configured for insertion at least partially into an intervertebral space between adjacent opposed vertebrae to distract the adjacent vertebrae to a desired predetermined distracted position. At least one anchoring member may be associated with the surgical retractor to facilitate mounting thereof to the vertebrae. The drill instrument includes an elongate member having a longitudinal passageway and defining at least one distal cutting surface and a drill member disposed within the elongate member and having a distal drill head. The drill member is rotatably movable within the elongate member and is also longitudinally fixed to the elongate member such that advancement of the drill member within the retractor causes corresponding advancement of the elongate member such that the distal cutting surface of the elongate member and the distal drill head of the drill member cooperate to cut a non-circular, e.g., an elliptical-shaped, bore in the adjacent vertebrae. Preferably, the elongate member of the drill instrument includes first and second diametrically opposed distal cutting surfaces. The cutting surfaces may be arcuately-shaped.