Frameless stereotaxy as an alternative to fluoroscopy for transsphenoidal surgery: use of the InstaTrak-3000 and a novel headset.

Our aim was to evaluate the applicability of an electromagnetic-based frameless stereotactic system for use in transsphenoidal surgery. The system utilizes a novel headset that acts as a replaceable fiducial frame as well as a fixation point for the system's transmitter. It can replace the fluoroscope as a guide to navigation in the sphenoid sinus and sella. The system was used in a consecutive series of 11 patients undergoing transsphenoidal surgery. It was used in conjunction with intraoperative fluoroscopy. We found the Instatrak-3000 to correlate well with lateral fluoroscopic images, and provide additional information in the axial and coronal planes. The InstaTrak-3000 frameless stereotactic system is accurate and obviates the need for intraoperative fluoroscopy during transsphenoidal surgery. Compared to other frameless systems, it avoids the use of fiducial skin markers and head fixation. In common with other frameless stereotactic systems, it provides additional information important for safely approaching the sella and avoids intraoperative radiation exposure for the patient and operating room staff.