Automated planning of mandible reconstruction with fibula free flap based on shape completion and morphometric descriptors

Abstract

Vascularized fibula free flap (FFF) grafts are frequently used to reconstruct mandibular defects. However, the current planning methods for osteotomy, splicing, and fibula placement present challenges in achieving satisfactory facial aesthetics and restoring the original morphology of the mandible. In this study, we propose a novel two-step framework for automated preoperative planning in FFF mandibular reconstruction. The framework is based on mandibular shape completion and morphometric descriptors. Firstly, we utilize a 3D generative model to estimate the entire mandibular geometry by incorporating shape priors and accounting for partial defect mandibles. Accurately predicting the premorbid morphology of the mandible is crucial for determining the surgical plan. Secondly, we introduce new two-dimensional morphometric descriptors to assess the quantitative difference between the planning scheme and the full morphology of the mandible. We have designed intuitive and valid variables specifically designed to describe the planning scheme and constructed an objective function to measure the difference. By optimizing this function, we can achieve the best shape-matched 3D planning solution. Through a retrospective study involving 65 real tumor patients, our method has exhibited favorable results in both qualitative and quantitative analyses when compared to the planned results of experienced clinicians using existing methods. This demonstrates that our method can implement an automated preoperative planning technique, eliminating subjectivity and achieving user-independent results. Furthermore, we have presented the potential of our automated planning process in a clinical case, highlighting its applicability in clinical settings.