The Role of 3D Simulation and Osteotomy Guides in Improving Surgical Outcomes for Complex Spinal Deformities: A Comparative Study

Background Complex spinal deformities, characterized by rigidity and imbalance, pose significant surgical challenges due to difficulties in correction and associated neurological risks. Recent advances in 3D-printed osteotomy guides offer a promising approach to improve the precision of vertebral cutting. This study retrospectively compares the corrective outcomes of standalone 3D simulation planning versus combined 3D planning with osteotomy guides. Methods A retrospective cohort study was conducted on 50 patients with complex spinal deformities underwent spinal surgery between 2022 and 2025. All patients underwent global spine 3D reconstruction and simulated osteotomies which based on curve patterns and sagittal/coronal balance preoperatively. Patients were divided into freehand correction group and osteotomy guides group.The correction outcomes of various deformity types and surgical approaches were compared between the two cohorts. Intraclass correlation coefficient (ICC) was used to assess the consistency of osteotomy outcomes by two groups. Results 45 patients were included, with 23 patients undergoing freehand correction only and 24 patients undergoing combined osteotomy guides. The average main curve (98.64 ± 33.21°) significantly decreased to 40.7 ± 13.3° postoperatively. The freehand correction group demonstrated significantly lower correction rates compared to the guides group (55.9 ± 9.1% versus 62.4 ± 14.1%, p = 0.02). There was no significant differences observed in surgical time and estimated blood loss (EBL) between groups (p = 0.18 and p = 0.37). The use of patient-specific osteotomy guides in PSO procedures resulted in significantly better correction (mean 56.1°±30.8°) versus freehand technique (mean 42.4°±11.4°, p = 0.03). Superior consistency was achieved by the osteotomy guides group compared to the freehand surgical group (ICC = 0.981 vs 0.668). Conclusion Utilizing preoperative 3D surgical simulation, osteotomies performed with 3D-printed patient-specific guides achieved significantly better correction accuracy than freehand techniques. The osteotomy using patient-specific guides demonstrated high fidelity to preoperative simulation.