A system for precision guidance of surgical procedures on a patient issuggested, comprising: a three-dimensional digital representation of thepre-procedural geometry of a relevant part of the patient, athree-dimensional digital representation of the intended post-proceduralgeometry of the relevant part of the patient including any implant or otherstructures intended to be attached to the patient, a movableelectro-optical camera mounted in a known position and orientation relative toa surgeon such as a head mount, a first carrier comprising at least 3targets to be observed by the camera, said carrier to be mounted in a knownposition and orientation relative to the relevant part of the patient, asecond carrier comprising at least 3 targets to be observed by thecamera, said carrier to be mounted in a known position and orientationrelative to an implant or surgical instrument, a computer for calculating therelative positions of the first and second carriers with at least 3 targets,and of the camera , based on observations from the camera, software,residing on the computer , calculating the relevant projection of a digitalrepresentation of the patient to a display in order for the displayedprojection to match with the surgeons current physical view of the patient.
