Accuracy and workflow of navigated spinal instrumentation with the mobile AIRO^® CT scanner

Purpose: Current solutions for navigated spine surgery remain hampered by restrictions in surgical workflow as well as a limited versatility and applicability. Against this background, we report the first experience of navigated spinal instrumentation with the mobile AIRO^® intraoperative computed tomography (iCT) scanner. Methods: AIRO^® iCT was used for navigated posterior spinal instrumentation of 170 screws in 23 consecutive patients operated on in our Department between the first use of the system in May 2014 and August 2014. The indications for AIRO^® were based on the surgical region, anatomical complexity and the need for >3 segment instrumentation. Following navigated screw insertion, screw positions were confirmed intraoperatively by a second iCT scan. CT data on screw placement accuracy were retrospectively reviewed and analyzed by an independent observer. Results: AIRO^®-based spinal navigation was easy to implement and successfully accomplished in all patients, adding around 18–34 min to the net surgery time. A systematic description of the authors’ approach, setup in the OR and workflow integration of the AIRO^® is presented. Analysis of screw placement accuracy revealed 9 (5.3 %) screws with minor pedicle breaches (<2 mm). A total of 7 screws (4.1 %) were misplaced >2 mm, resulting in an accuracy rate of 95.9 %. Conclusions: The AIRO^® system is an easy-to-use and versatile iCT for navigated spinal instrumentation and provides high pedicle screw accuracy rates. Although the authors’ experience suggests that the learning curve associated with AIRO^®-based spinal navigation is steep, a systematic user-based approach to the technology is required.