A robotic system for performing minimally invasive spinal stabilization, using two screws inserted in oblique trajectories from an inferior vertebra pedicle into the adjacent superior vertebra body. The procedure is less traumatic than such procedures performed using open back surgery, by virtue of the robot used to guide the surgeon along a safe trajectory, avoiding damage to nerves surrounding the vertebrae. The robot arm is advantageous since no access is provided in a minimally invasive procedure for direct viewing of the operation site, and the accuracy required for oblique entry can readily be achieved only using robotic control. This robotic system also obviates the need for a large number of fluoroscope images to check drill insertion position relative to the surrounding nerves. Disc cleaning tools with flexible wire heads are also described. The drilling trajectory is determined by comparing fluoroscope images to preoperative images showing the planned path.