Three-Dimensional Patient-Matched Template Guides Are Able to Increase Mean Diameter and Length and to Improve Accuracy of Cortical Bone Trajectory Screws: A 5-Year International Experience

OBJECTIVE: To analyze whether significant differences exist between free-hand three-dimensional (3D) planning -guided cortical bone trajectory (CBT) screw placement and 3D-printed template -guided CBT screw positioning in terms of accuracy, size of screws, and potential complications.METHODS: In this retrospective study, data of adult pa-tients in whom CBT screws were placed for lumbar degenerative pathologies were extracted from a prospec-tively collected database and analyzed. Patients in whom screws were placed using free-hand 3D planning -guided technique were compared with patients in whom screws were positioned using customized 3D-printed templates. Size of the screws, accuracy, clinical outcomes, and complications were analyzed.RESULTS: The study evaluated 251 patients (1004 screws). The free-hand 3D planning -guided group included 158 patients (632 screws), and the 3D-printed template -guided group included 93 patients (372 screws). The 3D-printed template -guided group involved screws of larger size from L3 to S1. Differences between the 2 groups in terms of accuracy parameters reached statistical sig- -ificance (P pound 0.05).CONCLUSIONS: With the use of 3D patient-matched template guides, mean diameter and length of CBT screws could be safely increased due to improved accu-racy of screw placement. Based on previous evidence regarding CBT biomechanical properties, these advantages could allow increased fixation strength over traditional convergent pedicle screw trajectories. Further biome-chanics studies are needed.