15 - Safety and Accuracy of Cannulated Pedicle Screw Placement in Scoliosis Surgery: A Comparison of Robotic Navigation, O-Arm-Based Navigation, and Freehand Techniques—A Prospective Cohort Study

Introduction: Screw placement in scoliosis surgery is challenging owing to vertebral rotation, smaller pedicle size, and a more complex 3D structure than normal. To improve pedicle screw positioning, several techniques have been developed, including navigation technology and robot-assisted technology to decrease the risk of misplaced screws and the associated complications. There were limited studies to compare the safety and accuracy of different techniques of cannulated pedicle screw placement in scoliosis surgery.

Objectives: This prospective study was to compare the safety and accuracy of cannulated pedicle screw placement using a robotic navigation technique, O-arm-based navigation technique, or freehand technique.

Methods: This study analyzed 143 consecutive patients with scoliosis. Forty-three patients underwent robotic-navigation-assisted pedicle screw insertion (Group A), 49 patients underwent O-arm-based navigation-guided pedicle screw insertion (Group B), and 51 patients underwent freehand pedicle screw insertion (Group C). The primary outcome measure was the accuracy of screw placement. Secondary outcome parameters included operation time, blood loss, radiation exposure, and postoperative stay.

Results: A total of 2753 cannulated pedicle screws were implanted in 143 patients. The accuracy rate of the first pedicle screw placement (grades A and B) during operation was significantly greater in Group A (94.7%) than in Group B (89.2%; P< 0.001). The accuracy rate of clinically acceptable screws postoperatively decreased in the order of Group A (96.7%) > Group B (93.0%) > Group C (80.4%; P< 0.01). There were no significant differences in blood loss or postoperative stay among three groups (P>0.05). The operation times of Group A and Group B were significantly longer than that of Group C (P < 0.05). Radiation exposure for patients decreased in the order of Group A > Group B > Group C (P < 0.001). Surgeon radiation exposure was significantly less in Group A and Group B than in Group C (P < 0.001).

Conclusion: The robotic navigation and O-arm-based navigation techniques effectively increased the accuracy and safety of pedicle screw insertion alternative to the conventional freehand technique in scoliosis surgery. Compared with the O-arm-based navigation technique, the robotic navigation technique increases the mean operation time, but also increases the accuracy of pedicle screw placement. A three-dimensional scan after insertion of the K-wire may increase the accuracy of pedicle screw placement in the O-arm-based navigation technique.