HOW TO AVOID VASCULAR COMPLICATIONS IN EN DONASAL SINUS SURGERY .2. PRE-OPERATIVE AND INTRAOPERATIVE IMAGING

Computer-assisted surgery (CAS) is a new intraoperative localization s ystem that is based on digital image generation devices. The system ha s been used in 189 cases of paranasal sinus procedures, employing comp uted tomography (CT) image data. Highly accurate imaging and localizat ion of bony structures can be achieved in this way, although definitio n of vascular structures is limited by representation attributes of ve ssels in CT. Algorithms have now been developed for the use of magneti c resonance angiography (MRA) data with the system. CAS was used in si x cases of endonasal surgery. Imaging helped substantially in all case s, but its application was limited by incomplete reflection of small v essels. In one case, intraoperative findings showed MRA-inherent inacc uracies. These might be avoided using correction programs and phantom selection (shimming) procedures in the future. Additionally, matching of different imaging modalities should improve intraoperative applicat ions of CAS.