Anatomic basis for an algorithmic approach for free fibula flap donor side selection in composite oro-mandibular defects

Introduction: Head and neck oncological resections may result in composite oro-mandibular defects involving the oral mucosa (lining), mandibular bone and the skin (cover). Reconstructive options for such defects have evolved over a period. Free fibula flap reconstruction is currently accepted the world over as the gold standard for oro-mandibular defect reconstruction. Existing literature provides conflicting views about the use of a particular side and orientation of the fibula flap for achieving the optimal outcome. The purpose of this study is to confirm anatomically the effect of bone, soft tissue and vessel orientation on the ease of doing reconstruction. Materials and Methods: This is a cadaveric study. A mandibular model with a defect was used. This was pre plated to maintain continuity. Composite fibula flaps of the same dimension were harvested from both legs of a fresh cadaver. The harvested flaps were used to reconstruct the mandibular defect in different orientations and the best configuration for each reconstructive requirement was assessed. Results: Keeping the peroneal surface for plating, that is, facing outwards, four different configurations of the fibula flap are possible for a given mandibular defect. With a posterior vascular pedicle ipsilateral fibula is suitable for skin cover and contralateral for mucosal lining and the reverse for an anteriorly placed pedicle. Conclusion: The algorithm based selection of appropriate sided fibula flap facilitates complex mandibular reconstruction by placing the right kind of tissue at the right place and helps in reducing the donor site morbidity by allowing the surgeon to harvest only the required amount of skin.