Clinical Application of Atlantoaxial Pedicle Screw Placement Assisted by a Modified 3D-Printed Navigation Template

OBJECTIVES: To investigate the primary clinical value of atlantoaxial pedicle screw placement assisted by a modified 3D-printed navigation template. METHODS: We retrospectively analyzed the cases of 17 patients treated from June 2015 to September 2016 with atlantoaxial pedicle screw placement assisted by a modified 3D-printed navigation template. All procedures were performed prior to surgery, including thin-slice CT scanning, medical image sampling and computerized 3D modeling of the atlantoaxial joint, optimal pedicle screw trajectory determination, and anatomical trait acquisition for the atlantoaxial pedicle, spinous process of the axis, vertebral lamina and posterior lateral mass, and design of a reverse template. During surgery, a navigation template was tightly attached to the atlantoaxial joint to assist in pedicle screw placement. Surgeons subsequently used an electric drill to remove the template through a guide channel and then placed the atlantoaxial pedicle screw. Observed indexes included the VAS score, JOA improvement rate, surgery duration, and blood loss. RESULTS: Surgery was successful in all 17 patients, with an average operation duration of 106 +/- 25 min and an average blood loss of 220 +/- 125 ml. Three days postoperatively, the VAS score decreased from 6.42 +/- 2.21 to 3.15 +/- 1.26. Six months postoperatively, the score decreased to 2.05 +/- 1.56. The postoperative JOA score increased significantly from 7.68 +/- 2.51 to 11.65 +/- 2.72 3 d after surgery and to 13.65 +/- 2.57 after 6 months. Sixtyeight pedicle screws were inserted successfully, with 34 in the atlas and 34 in the axis. According to the Kawaguchi standard, 66 screws were in grade 0 (97.06%), and 2 were in grade 1 (2.94%). The pre- and postoperative transverse and sagittal screw angles showed no significant differences. CONCLUSIONS: Atlantoaxial pedicle screw placement assisted by a modified 3D-printed navigation template is worth recommending due to the improved accuracy in screw placement, improved patient safety and beneficial clinical effects.