Application of Flexor Hallucis Longus Muscle in Mandibular Reconstruction for Hardware Coverage in Postoperative Radiotherapy.

Background: Mandibular reconstruction after head and neck cancer surgery is mostly a complex procedure, especially when followed by radiotherapy. Although the fibular free flap remains a reliable option, radiotherapy can compromise soft tissue healing, increasing the risk of hardware exposure and osteoradionecrosis.

Purpose: This technical note explores the use of the flexor hallucis longus (FHL) muscle in mandibular reconstruction, specifically for improving soft tissue coverage over reconstruction plates and minimizing radiation-related complications.

Methods: The FHL muscle was harvested alongside the fibular flap and was positioned over the reconstruction plate to provide a vascularized, durable layer of soft tissue. Its strong blood supply from the posterior tibial artery, combined with its bulk and resilience, was intended to offer better protection and healing in patients undergoing postoperative radiotherapy.

Results: Clinical experience showed that the FHL muscle helped reduce the risk of plate exposure and radiation-induced damage. Its vascularity not only promoted healing, while its bulk acted as a cushion against shear forces and tissue breakdown, but also this muscle also contributed to maintaining tissue integrity and minimizing the risk of osteoradionecrosis, with no significant increase in donor site morbidity.

Conclusion: Incorporating the FHL muscle in fibular flap-based mandibular reconstruction adds meaningful protection for patients receiving radiotherapy. It supports healing, safeguards underlying hardware, and improves both functional and aesthetic outcomes.