Passive marker computer-aided sinonasal and cranial base surgery: observations from a learning curve.

To assess the feasibility of passive marker computer-aided surgery in a single institution, we performed 22 procedures in 21 patients with disorders including sinonasal tumors (n = 9), fungal sinusitis (n = 4), recurrent polyps (n = 3), chronic sinusitis (n = 3), and cerebrospinal fluid rhinorrhea (n = 2). Passive marker computer-aided surgery was successful in 19 of the 21 patients. The accuracy was on the order of 1.35 mm. Probe conversion, rotation, and cordlessness were helpful in all 19 cases. The system helped with landmarks (n = 14), margins (n = 7), skull base (n = 6), orbit (n = 5), and approach (n = 4). Computer-aided surgery accurately confirmed the location of an instrument and demonstrated tumor-normal tissue interfaces. It aided the surgeon in procedures on the sinonasal area and cranial base. The potential advantages of a passive marker system as compared with other available technologies center around the ability to convert and/or rotate virtually any instrument to a cordless imaging probe on demand during the operation.