Robot-assisted screw fixation in upper cervical spine using TiRobot system: an accurate and reliable procedure

摘要

Screw fixation in upper cervical spine surgery is one of the most challenging spinal procedures. For that reason, the free-hand techniques are not a reliable procedure in upper cervical spine. Wei Tian reported the first posterior C1-2 transarticular screw fixation which was assisted by robotic systems using TiRobot system in 2016. Our study was aimed to assess the accuracy and reliability of screw fixation in upper cervical spine prospectively. All the patients undergoing screw fixation assisted by robotic system (TiRobot) in upper cervical spine were prospectively studied from August 2015 to January 2018 in Beijing Jishuitan hospital. During surgeries, intraoperatively obtained images by C-arm were transferred into the TiRobot system and three-dimensional images were created. Surgeons' plannings of the screw trajectories were performed in TiRobot system. Afterwards, the robot arm with a guidance tube on its end was automatically moved to the entry point of each trajectory and held still. Guiding pins were inserted and followed by cannulated or conventional screws placements. A fluoroscopic re-scan by C-arm was performed, and the merging of two sets of images demonstrated the deviations between the planned and real trajectories. The deviations were analyzed and any intraoperative difficulties or errors were recorded. Postoperatively, any screw perforations were reviewed and recorded on CT scan images. Twenty-six patients (13 males/13 females) were included in this study. The average age was forty-nine. The underlying diseases of these patients covered dens fractures, Hangman's fractures, congenial and acquired deformities. 64 screws were placed assisted by TiRobot system. The average deviation between the planned and real trajectories was 0.9 mm. No screw perforations were detected on postoperative CT scans. Cervical spine, particularly the upper cervical spine has small size bony structures, higher accuracy requirements are significantly important. The results of our study showed only 0.9 mm deviations between planned and real trajectories occurred. This level of accuracy allowed safe and accurate placement of screws in upper cervical spine and no screw perforations were observed. For that reasons, screw fixation in upper cervical spine is an accurate and reliable procedure using TiRobot system.