[CAS (computer assisted surgery). A new procedure in head and neck surgery].

Computer assisted surgery (CAS) is a new imaging technique designed to assist the head and neck surgeon during surgery. This method is based upon a three-dimensional volume model of the patient's skull generated by computer tomographic imaging procedures such as CT and MR. Body points can be marked in the 3-D model by intra-operative correlation of model and patient using a volume digitizer. Real-time positioning of surgical instruments without visual control can be achieved. The use of the system in surgery of the skull base, orbit and the paranasal sinuses is demonstrated.