COMPUTER-ASSISTED RESECTION OF BENIGN SINONASAL TUMORS WITH SKULL BASE AND ORBITAL EXTENSION

Objective: To use freehand, real-time, intraoperative, 3-dimensional c omputed tomography (3-D CT) localization to assist with resection of s inonasal lesions with skull-base and/or orbital extension. Design: The 3-D CT is computer-assisted technology using the preoperative CT scan as a road map for resection of lesions. Previous technology, while re sulting in little intraoperative error, required use of a somewhat cum bersome rigid articulated arm and attached probe, limiting mobility an d requiring rigid fixation of the head to maintain system reference. A new freehand version of this technology, eliminating these limitation s, has been used for resection of benign sinonasal lesions with skull- base and/or orbital extension. Setting: Tertiary care, university-base d practice. Patients: Seven patients prospectively selected with benig n lesions involving the sinonasal cavity and orbit and/or skull base. Intervention: All patients underwent surgical resection of their tumor s using endoscopic, open, or com-bined procedures with the assistance of freehand 3-D CT localization. Main Outcome Assessment: Surgeon asse ssment of usefulness. Results: In several cases, the device assisted t he operator in determining the exact location of a displaced optic ner ve, ensuring vision preservation, while in other cases, the location a nd depth of skull-base penetration was clearly determined, allowing re section via a transnasal endoscopic approach. In addition, the device was useful for determining the depth of necessary resection for optima l cosmetic result. In all cases, system accuracy was within less than 2 mm at the operative site. System limitations included need for an ad ditional preoperative CT and time required at the beginning of the cas e for system setup and registration. Conclusions: Freehand 3-D CT, whi le still with limitations, offers the advantage of increased surgical safety, aiding anatomic understanding in distorted surgical fields for resection of benign sinonasal tumors with orbital and skull-base exte nsion.