Accuracy of Robot-assisted anterior transpedicular screws in the subaxial cervical spine: an experimental study on human specimens

Cong Lin¹Xiaowei Sun²Xiaolu Xi²Ke Yuan²Yajing Cao²Qiang Xie²Yue Zhu^1*

• ¹Department of Orthopaedics, The First Affiliated Hospital of China Medical University, Shenyang, China
• ²Wuhan United Imaging Surgical Co., Ltd, Wuhan, China

Study Design: Prospective study. Objectives: This study aimed to evaluate the accuracy and safety of robot-assisted anterior transpedicular screw (ATPS) fixation in human cervical spine specimens. Methods: A spine robotic system was used to implant thirty-six 1.2 mm Kirschner wires (K-wires) into the cervical pedicles (C4–C7) of five human specimens. Accuracy was assessed by comparing the planned trajectories with the actual K-wire positions. The Gertzbein-Robbins classification system (GRS), adapted for cervical pedicles, was used to evaluate accuracy; Grades A and B (<2 mm pedicle breach) were considered clinically acceptable. Secondary metrics included entry point and angle offsets. Results: Of the 36 K-wires implanted, 9 were placed in C4 and C6, 10 in C5, and 8 in C7. According to the adapted GRS, 25 placements (69.4%) were Grade A, 10 (27.8%) were Grade B, and one was Grade C, resulting in a 97.2% clinically acceptable placement rate. The mean target offset was 2.29 ± 1.72 mm, the entry offset was 2.47 ± 1.57 mm, and the angle offset was 5.67 ± 3.72°. No significant differences were observed between the left and right sides (p > 0.05). Conclusions: Robot-assisted ATPS fixation in cervical specimens achieved high accuracy with 97.2% of placements rated clinically acceptable, indicating its technical feasibility and potential utility in anterior cervical procedures.