An update-navigation system for the resection surgery of brain tumor was developed using newly designed fiducial markers and intraoperative magnetic resonance imaging (MRI). Sixty-seven patients underwent resection surgeries aided by this system. The aim of present study was to evaluate the registration error in the update-navigation system when the new markers were used. The registration error was measured for the difference between patient positions (prone and supine), between imaging conditions (T1-weighted and T2-weighted), and between surgeon's experience (experienced and less experienced), revealing no significant differences.
The registration error was 0.84±0.44mm (n=55) for prone position and 0.88±0.47mm (n=12, p>0.1) for supine position. The registration error was 0.90±0.35mm (n=45) for T1-weighted images and 0.75±0.45mm (n=22, p=0.08) for T2-weighted images. The registration error was 0.84±0.41mm (n=60) for the experienced surgeons and 0.98±0.73mm (n=7, p>0.1) for the less experienced ones.
The present results indicate that the new fiducial markers allowed the navigation system to have stable registration errors irrespective of patient position, imaging condition, and surgeon's experiences. Furthermore highly accurate resection surgery is assured with this navigation system when the new markers are used.
