Late onset fibula free flap failure due to osteoradionecrosis in the era of intensity-modulated radiotherapy: a case report

Introduction: Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity and often requires extensive resection with reconstruction. Fibula free flap (FFF) is the preferred bony reconstructive option in head and neck oncology, as failure rates are the lowest of all free flaps. Late FFF failure in the era of intensity-modulated radiotherapy (IMRT) is rare. Case report: Fourty-four-year-old male smoker, diagnosed with G2 OSCC. He underwent tumour resection, partial glossectomy, mandibular reconstruction with an osteomyocutaneous FFF and adjuvant IMRT. After 4 years, he experienced total flap failure due to mandibular osteoradionecrosis (ORN), necessitating a salvage pectoralis major myocutaneous (PMMC) flap. Discussion: Late FFF failure in IMRT is sporadic. This case highlights the synergistic effects of smoking-related vascular compromise and radiotherapy-induced hypoxia and hypocellularity as the pathophysiology behind flap failure. The choice of PMMC for salvage procedure is discussed in the context of its clinical implications, along with the importance of adhering to long-term follow-ups and mitigating risk factors for high-risk patients to improve patient quality of life. Conclusions: In modern medicine with advanced radiation therapy techniques, every case of FFF failure is a learning opportunity to improve patient care. The importance of long-term surveillance and structured smoking cessation support is crucial to optimise health care outcomes and preserve quality of life for head and neck cancer patients.