Clinical Application Of 3D Individualized Guide Plate In Atlantoaxial Pedicle Screw Placement

Objective: To improve the accuracy and safety of pedicle screw placement in atlantoaxial spine by exploring 3D individualized guide plate.Methods: A total of 20 cases of atlantoaxial fracture and dislocation were collected from October 2016 to February 2019 in the Department of Orthopaedics,Affiliated Hospital of Inner Mongolia Medical University and Affiliated People's Hospital.All patients were diagnosed by imaging data and clinical manifestations.Before operation,imaging data were obtained by CT scanning.The data were imported into Mimics and other software to design suitable for each individual.Screw implantation navigation template,using 3D printer to print out the template,were implanted into the atlantoaxial pedicle screw by the same operator using the navigation plate.The average amount of bleeding during operation and operation time were recorded.All patients underwent CT scan of cervical spine after operation.According to the relative relationship between the screw and the four walls of the pedicle,the accuracy of the implantation was evaluated according to Kawaguchi's method,and the ideal screw was set before operation by comparing with Kawaguchi's method.The accuracy of screw placement was evaluated by angle and actual screw angle after operation.Results: All the operations were successful without any new vascular and nerve injuries.The operation time was 118±16 minutes and the amount of bleeding was 236±70 ml.A total of 80 screws were implanted in all patients,including 40 atlas and 40 axis.Four atlas screw and four axis screw were replaced by bare-handed screw because of the attachment problem of guide plate.A total of 72 screws were included in the study.According to Kawaguchi's evaluation method,69(95.83%)grade0 screw(accuracy rate was 95.83%,69/72)grade I screw(accuracy rate was 4.17%,3/80),grade II screw and grade III screw were 0.There was no significant difference between the ideal head tilt and the upper tilt before operation and the actual operation(P > 0.05).Conclusion: The application of individualized printing guide plate in nail placement has the characteristics of high accuracy and safety,and can accurately complete the operation plan.It is worth popularizing in clinical application.