Design and Application of Individualized, 3-Dimensional-Printed Navigation Template for Placing Cortical Bone Trajectory Screws in Middle-Upper Thoracic Spine: Cadaver Research Study.

Objective: To evaluate the safety and accuracy of use of a 3-dimensional printed navigation template in the placement of a cortical bone trajectory (CBT) screw in the middle-upper thoracic spine.

Methods: Ten human cadavers were included in the study. Sixty CBT screws were placed on 1 side, using the free-hand technique, and 60 CBT screws were placed on the other side, using the navigation template that was designed and printed using data from 10 cadavers. The safety and accuracy of use of the CBT screws were directly evaluated by radiography and computed tomography.

Results: Computed tomography revealed that 2 and 3 of 60 screws, placed using the navigation template, were broken in the medial or lateral areas and in the superior or inferior pedicle wall, respectively. Furthermore, 8 screws were broken in the medial or lateral areas and 11 screws were broken in the superior or inferior pedicle wall when the free-hand technique was used. Radiography revealed that 3 screws in zone I, 55 screws in zone II, and 2 screws in zone III were placed using the navigation template. Furthermore, 7 screws in zone I, 45 screws in zone II, and 8 screws in zone III were placed using the free-hand technique.

Conclusions: In this cadaver study, insertion of the CBT screws in the middle-upper thoracic spine with the assistance of the navigation template was safe and convenient.