Computer aided design modeling techniques for preoperative surgical planning in facial reconstruction and cleft surgery

Facial reconstruction and cleft surgeries require precise identification of defect regions and careful planning to restore anatomical structure and function. Conventional approaches based on two-dimensional imaging and intraoperative judgment may lead to variability in surgical outcomes and increased operative time. Patient specific computed tomography (CT) data were used to develop three-dimensional (3D) computer aided design (CAD) models of the maxillofacial region. The workflow included segmentation, thresholding, region-based editing and smoothing to obtain accurate anatomical structures. CAD based techniques such as mirror-assisted reconstruction, virtual osteotomy, measurement based planning and layer-by-layer defect modeling were applied for preoperative surgical planning. The approach was evaluated through seven clinical case studies, including facial reconstruction conditions (tumor-affected mandible, temporomandibular joint ankylosis, condylar hyperplasia and mandibular prognathism) and cleft related defects (unilateral complete cleft lip and palate cases with alveolar defects). The CAD based approach enabled visualization of defect geometry and supported quantitative estimation of surgical parameters. In facial reconstruction cases, mirror-based and measurement-driven techniques facilitated planning of resection and alignment. In cleft cases, layer-based reconstruction and subtraction modeling allowed patient-specific design of graft shape, volume, and spatial distribution. In complex cases, patient-specific graft models enabled pre-fabrication, patient-specific graft models provided geometry that could support pre-fabrication and preoperative graft planning. Overall, the method supported systematic and patient-specific preoperative surgical planning across the selected cases. The proposed CAD based framework provides an effective approach for preoperative surgical planning in maxillofacial reconstruction and cleft surgeries by supporting patient specific anatomical assessment and systematic surgical planning.