The robot is tethered to a workstation that provides image registration, kinetic calculations, and real-time motion control of the robot arm. The CT plan is refor­matted intraoperatively to match the patient’s position on the OR table using bipla­nar uoroscopy (although now can also be registered by using navigation technology and the O-arm). The software then reformats the CT scan to match each vertebra's position to the patient’s spine as positioned on the OR table. The software selects critical landmarks such as vertebral endplates, pedicles, and posterior vertebral mar­gins and rejects image artifacts such as evoked potential wires, electrocautery leads, and OR table pads. As compared to conventional surface topography registration utilized in navigation systems, this image registration process is entirely software­based and has a matching tolerance of 1.2 mm [22]. Unique to this registration process is that each vertebral segment is registered individually. The planned screw trajectories can also be adjusted in real-time to accommodate the limits of reach by the robot guide tubes. Although obstruction by the mounting rail and the robot itself could limit reach, three different arm attachments options with a drill/tap guide on end (guide tubes) could be utilized to accomplish accurate and proper stereotaxis [24]. Using a power drill the pedicle could be cannulated, utilizing a reciprocating or constant rotation at a selected speed that allows for proprioceptive feedback. Little axial pressure is required to advance the drill through the pedicle, easily detecting a cortical breech or sensing an “in-out-in” trajectory with the loss of drill resistance.