Abstract: BACKGROUND: It is difficult to insert pedicle screws in the correction of adolescent idiopathic scoliosis. Research shows that robot-assisted surgery for adolescent idiopathic scoliosis can improve the accuracy of pedicle screw placement and reduce intraoperative bleeding.
OBJECTIVE: To explore the safety and accuracy of the orthopedic Tianji robot in the correction of adolescent idiopathic scoliosis.
METHODS: The clinical data of 40 cases of adolescent idiopathic scoliosis treated with posterior pedicle screw fixation from June 2018 to March 2022 were analyzed retrospectively. According to the difference in auxiliary equipment, the patients were divided into a robot group (C-arm X-ray combined with a robot-assisted screw placement; n=18) and an unarmed group (simple C-arm X-ray-assisted screw placement; n=22). The indexes and imaging data of patients of the two groups during the perioperative period and follow-up period were compared, including the visual analog scale score, the Japanese Orthopaedic Association score, the operation time, the intraoperative blood loss, the number of intraoperative fluoroscopy times, the length of hospital stay, the spinal correction rate, and the accuracy rate of nail placement.
RESULTS AND CONCLUSION: (1) The operations of the two groups were completed successfully, and all the patients were followed up for (8.45±1.81) months after the procedure. (2) The number of intraoperative fluoroscopy times and intraoperative blood loss were significantly less and operation time was significantly longer in the robot group compared with the unarmed group (P < 0.05). (3) Compared with the preoperative procedure, the visual analog scale score and Japanese Orthopaedic Association score of the two groups were significantly improved at the last follow-up (P < 0.05). (4) Postoperative imaging examination showed that the Cobb angle of the main bend in both groups was significantly lower than that before the operation (P < 0.05). (5) Three hundred and six screws were placed in the robot group, and the accuracy of placing screws was 95.8%, while the accuracy of grade A screws was 90.2%. Three hundred fifty-four nails were implanted in the unarmed group, and the accuracy of nail implantation was 91.0%, while the accuracy of grade A screw implantation was 81.4%. There was a significant difference in the accuracy of nail implantation between the two groups (P < 0.05), and the accuracy of grade A screw implantation in the robot group was significantly higher than that in the unarmed group (P < 0.05). (6) The C-arm X-ray combined with a robot-assisted screw placement is safer and more accurate than the simple C-arm X-ray-assisted screw placement. 

Key words: orthopedic Tianji robot, adolescent idiopathic scoliosis, pedicle screw, screw implantation accuracy, Cobb angle