Comparison of accuracy of maxilla between virtual surgical planning and conventional surgical planning in bimaxillary orthognathic surgery: a randomized controlled trial

Background Virtual surgical planning (VSP) improves accuracy in orthognathic surgery, but its differences from conventional surgical planning (CSP) remain unclear. This study compares VSP and CSP accuracy in maxillary repositioning. Methods A randomized controlled trial of 20 patients undergoing bimaxillary surgery was conducted. Patients were assigned to VSP (3D planning, 3D-printed splints) or CSP (cast model surgery, conventional splints). Pre- and postoperative Computed Tomography (CT) scans were superimposed using voxel-based registration, measuring anteroposterior (Y), mediolateral (X), and vertical (Z) positional changes of A point, ANS, U1, U3, U6 landmarks. Results No significant differences in planned and actual surgical outcomes (p > 0.05). 2D planning (P2D) and 3D planning (P3D) showed significant differences in key maxillary landmarks, indicating that 3D planning provides additional refinements in skeletal positioning. However, VSP showed larger absolute discrepancies in U1L, U1R, U3L, U6L (p < 0.05), particularly in the anteroposterior (Y-axis) direction. Splint thickness and condylar simulation methods could also affect accuracy. Conclusions VSP and CSP provide comparable accuracy; however, VSP shows greater anterior-posterior discrepancies. Further studies should examine splint design and condylar modeling to optimize surgical precision.