Study on the accuracy of cervical pedicle screw placement assisted with improved 3D-printed drill guiding template

English Keywords:3D printing  Improved drill guiding template  Cervical pedicle screw placement

English Abstract:

  【Abstract】 Objectives: To explore the accuracy of pedicle screw placement assisted with improved 3D-printed drill guiding template in cervical spine. Methods: The clinical data of 60 patients undergone posterior cervical pedicle screw placement in our hospital between January 2016 and January 2023 were analyzed retrospectively, including 30 males and 30 females with an average age of 17-84 years(58.7±13.8 years). The patients were divided into guiding template group and free-hand group based on whether the guiding template was used to assist the placement of screws or not. The improved 3D-printed guiding template was used to assist cervical pedicle screw placement in the guiding template group(n=30), and the self-made angular-ruler was used in the free-hand group(n=30). There was no significant difference in age, gender ratio, and preoperative diagnosis between the two groups(P>0.05). Cervical CT scan was performed at one week after surgery, and the accuracy of pedicle screw placement was evaluated according to the Kaneyama standard: Grade 0, the screw was completely in the pedicle; Grade 1, the size of screw penetrating the cortex ＜50% of the screw diameter; Grade 2, the size of screw penetrating the cortex ≥50% of the screw diameter but not completely out; Grade 3, the screw was completely on the outside of the pedicle. The accuracy of pedicle screw placement(ratio of grades 0 and 1) and complications such as vascular and nerve injury, incision infection, cerebrospinal fluid leakage, screw loosening and breakage caused by screw misplacement were recorded. Results: A total of 152 pedicle screws were placed in the guiding template group, including 74 screws of grade 0, 68 of grade 1, 10 of grade 2 and 0 of grade 3, with an accuracy of screw placement of 93.4%. A total of 136 pedicle screws were placed in free-hand group, including 53 screws of grade 0, 61 of grade 1, 18 of grade 2 and 4 of grade 3, with an accuracy of screw placement of 83.8%. The accuracy of screw placement in the guiding template group was significantly higher than that in the free-hand group(P<0.05). There were no related complications such as vascular and nerve injury, incision infection and cerebrospinal fluid leakage caused by misplacement of pedicle screws. The patients were followed up for 5-29 months(14.2±7.7months), and there were no complications such as screw loosening or breakage. Conclusions: Improved 3D-printed drill guiding template can improve the accuracy of pedicle screw placement in cervical spine.