Intraoperative CT with integrated navigation system in spinal neurosurgery

For spinal surgery navigational system images are usually acquired before surgery with patients positioned supine. The aim of this study was to evaluate prospectively navigated procedures in spinal surgery with data acquisition by intraoperative computed tomography (iCT). CT data of 38 patients [thoracolumbar instability (n=24), C1/2 instability (n=6), cervicothoracic stabilization (n=7), disk herniation (n=1)] were acquired after positioning the patient in prone position. A sliding gantry 24 detector row CT was used for image acquisition. Data were imported to the frameless infrared-based neuronavigation station. A postprocedural CT was obtained to assess the extent of decompression and the accuracy of instrumentation. Intraoperative registration revealed computed accuracy <1 mm (0.9 + 0.1 mm) in all cases. Control-iCT revealed incorrect screw position >2 mm in 9/158 screws (5.6%), allowing immediate correction in five screws without any damage to vessels or nerves. There were three transient complications with clinical improvement in all patients. Intraoperative CT in combination with neuronavigation provides high accuracy of screw placement and thus safety for patients undergoing spinal stabilization. The procedure is rapid and easy to perform and-by replacing pre- and postoperative imaging-is not associated with additional exposure to radiation.