3D-Printed Screw-Rod Auxiliary System for Unstable Atlas Fractures: A Retrospective Analysis

Objective: To develop and validate a 3D-printed screw-rod auxiliary system for unstable atlas fractures. Methods: Fourteen patients who underwent occipitocervical fusion with the 3D-printed screw-rod auxiliary system enrolled in our hospital from 2017 to 2019 were reviewed. The operation time, blood loss and radiation times during the operation were recorded. The maximum fracture displacement values pre- and post-operation were measured based on CT imaging. All screw grades were evaluated after surgery. The O-C2 angle and OCI angle pre-operation, post-operation and at the last follow-up were measured. The dysphagia scale 3 and 12 months after surgery and the NDI 3 and 12 months after surgery were assessed. Results: The average surgery time, average blood loss and average radiation times for the 14 patients were 112.14 minutes, 171.43 ml and 5.07 times, respectively. There was a significant difference in maximum fracture displacement between pre- and post-operation values (P<0.05). A total of 56 screws were inserted; 3 screws were classified as grade 1, and the others were classified as grade 0. There was a significant difference in the O-C2 and OCI angles from pre-operation values to values 3 days after the operation (P=0.002, P<0.05); there was no significant difference in the O-C2 or OCI angle from 3 days after the operation to the last follow-up (P=0.079; P=0.201). The dysphagia scales of two patients were assessed as mild 3 months after surgery, and the others were assessed as normal. All patients’ dysphagia scores returned to normal 12 months after surgery. The average NDI and average neck VAS scores 12 months after surgery were 2.53 and 8.41, respectively. Conclusion: It is clinically feasible with the assistance of a screw-rod auxiliary system to perform occipitocervical fusion for unstable atlas fractures. This novel technique can objectively restore the occipitocervical angle of patients, and there are few postoperative complications.