Patient-specific 3D-printed spinal models improve pedicle screw placement accuracy in severe kyphoscoliosis: a comparative study

Objective: Accurate pedicle screw placement in severe kyphoscoliosis remains a major challenge due to distorted and rotated spinal anatomy.This study aims to evaluate whether the use of patient-specific 3-dimensional (3D) printed spinal models improves pedicle screw placement accuracy.Methods: Fourteen patients with severe kyphoscoliosis (Cobb angle >100) were included in the study.The study group (n = 7) underwent surgery using patient-specific 3D-printed spine models to assist freehand pedicle screw placement, while the control group (n = 7) underwent surgery using the standard freehand technique alone.Pedicle screw accuracy was scored from 0 to 3 on postoperative computed tomography scans.The Mann-Whitney U-test and Cliff's Delta were used for statistical analysis.Results: Maximum preoperative coronal and sagittal Cobb angles were higher in the control group (mean coronal angle, 106.57 19.76 vs. 128.86 21.42 and mean sagittal angle, 105.00 17.38 vs. 125.00 19.27) but the statistical difference between the groups was not significant.The mean screw malposition score was significantly lower in the 3D model group (Mean: 0.49 0.93) compared to the control group (Mean: 1.45 1.10) (U = 4802.5,P < .001).Effect size was large (Cliff's Delta = -0.66). Conclusion:The use of 3D-printed patient-specific spinal models significantly improves the accuracy of pedicle screw placement in severe spinal deformities and should be considered as an adjunct tool in complex deformity surgeries.