A comparison of image guidance systems for sinus surgery

Objective: Intraoperative computed tomographic guidance systems are available which utilize either electromagnetic (radiofrequency) or optical (infrared) signals to localize instruments within the surgical field. The objective of this study was to compare the use of these two different image guidance technologies for sinus surgery. Study Design: Prospective cohort study. Methods: The electromagnetic-based InstaTrak system (n = 24) and the optical-based Stealth-Station (n = 49) were compared in a series of 73 consecutive sinus series which utilized image guidance technology, Results: Both the electromagnetic and optical systems provided anatomic localization to within 2 mm during surgery. Intraoperative reregistration was effective in correcting for any anatomic drift. There were no intraoperative complications. Mean operative times were 156.3 +/- 8.9 minutes for the electromagnetic and 139.2 +/- 17.7 minutes for the optical system (P < .05), The average intraoperative blood loss did not differ significantly between groups (electromagnetic, 190.6 +/- 28.7 mL; optical, 172.4 +/- 23.0 mL). Each system was noted to have limitations. The presence of metallic objects in the operative field interfered with functioning of the electromagnetic system, whereas the optical system required a clear line of sight to be maintained between the infrared camera and surgical handpiece. Both systems required specialized headsets to be worn by patients during surgery to monitor head position. The electromagnetic system also required these headsets to be worn during the preoperative computed tomography scan. Conclusion: Although these two image guidance systems both proved valuable for anatomic localization during sinus surgery, individual preferences can be based on distinct differences in their design and operation.