Personalized guiding templates for pedicle screw placement

Introduction: Pedicle screw fixation is a standard procedure of spinal instrumentation. The aim of this work was to evaluate accuracy and safety of using personalized guiding templates for pedicle screw placement on thoracic spine. Methods and Results: We performed a computer tomography (CT) scan of the spine specimen to acquire virtual 3D model of the spine. Computer software (EBS^TM, Ekliptik, Slovenija) was used to design drill templates according to pedicle trajectories. Drill templates were then printed out of the biocompatible polymer using 3D printing technology. Templates were placed on the anatomic specimen vertebras anchoring at three sites - on the lamina at the base of the superior articular process on both sides and at the tip of the spinous process. Holes were drilled, and 3,5 mm screws inserted from T1 do T7 (7 pairs) using custom template for each vertebrae. CT scan was obtained after screw placement to evaluate screw positions. 13 screws were inside of pedicle trajectory without violation of pedicle wall with the tip inside of the vertebral body. One screw perforated medial pedicle wall. Conclusion: The potential use of such a navigational template to insert thoracic pedicle screws in spinal instrumentation is promising. This novel method could improve the accuracy of pedicle screw insertion and reduce the operating time and radiation exposure of spinal fixation surgery.