Personalized 3D Printing Pedicle Screw Guide Innovation for the Surgical Management of Adolescent Idiopathic Scoliosis Patients

ABSTRACT Study Design Prospective study. Objectives To assess the safety and efficacy of patient-specific 3D rapid-prototype printing technology for pedicle screw insertion in adolescent idiopathic scoliosis (AIS) patients. Methods The 3D pedicle screw guides were produced after selecting the fixation points for all individual levels to be used intraoperatively. Preoperative CT images recreated 3D bone models of each vertebra specific to each patient. Safe pedicle trajectories were determined in all three planes on these models. 3D printed guides were modelled according to these trajectories and manufactured with a biocompatible material. Postoperatively, all screws were evaluated and scored with CT as Class 1 (Accurate), Class 2 (Inaccurate) or Class 3 (Deviated). The mean angle between the inserted pedicle screw and the intended trajectory (ASIT), and the mean distance between the central longitudinal axis of a screw and pedicle (DBSP) were also measured. Results 134 screws were inserted. On the concave and convex sides, the mean medial malposition was 0.5±0.8 and 0.4±0.6 mm, the mean lateral malposition was 1.4±2.3 and 0.8±1.3 mm, ASIT was 4.2±4.6 and 4.3±6.0°, and DBSP was 1.5±2.1 and 0.9±1.2 mm, respectively. 117 screws were regarded as Class-1, 14 as Class-2, and 3 as Class-3. 92.5% of all screws inserted achieved positional accuracy. There were no screw-related complications. Conclusions This is one of the initial reports to note the novel design and implementation of patient-specific, 3D pedicle screw guides for AIS surgery. Our pilot study illustrated that the use of these low-cost personalized 3D guides is completely safe and effective in both convex and concave sides of the curves.