Osteoradionecrosis in osseous free flap reconstruction: Risk factors and treatment.

Objective: To determine the rate and risk factors for osteoradionecrosis (ORN) in osseous free flaps after postoperative radiation therapy (PORT). To describe the treatment of free flap ORN.

Methods: Seventy-four patients undergoing osseous free flap reconstruction were analyzed. Thirty-eight completed PORT. Patients were followed for ≥6 months.

Results: The rate of ORN was 34% overall; 0% with 50 to 59.9 Gy; 8% with 60 Gy; 40% with 66 Gy; 56% with 70 to 74.4 Gy. Mean time to ORN was 13.1 months. 0/28 patients without PORT developed free flap osteonecrosis. Multivariate analysis found the only factor predicting ORN: PORT >60 Gy, which increased the risk 21-fold. Treatment included PENTACLO, hyperbaric oxygen, and surgical debridement with 75% within 2 years.

Conclusion: PORT >60 Gy is significantly associated with free flap ORN. As the dose of adjuvant RT increases beyond 60 Gy, the risk of ORN in free flaps rises. Consideration should be given to lower PORT doses or delaying free flap reconstruction when feasible.