Osteoradionecrosis

Osteoradionecrosis (ORN) of bone is a late complication of radiotherapy characterized by exposed, necrotic bone in a region that has received ionizing radiation, typically persisting for more than three months. It most commonly affects the mandible after treatment for head and neck cancer, though the maxilla and other irradiated bones can be involved. The prevailing pathophysiology involves radiation-induced damage to bone vasculature, resulting in hypoxia, hypovascularity, and hypocellularity that impairs healing and predisposes to necrosis and infection.

Clinical features include dull jaw pain, loosening of teeth, nonhealing intraoral or extraoral wounds, exposed necrotic bone, infection, swelling, fistula formation, and in advanced cases pathologic fracture. Risk factors include higher radiation dose and concomitant chemotherapy, dental extraction after radiotherapy, poor dental status, smoking, and poor nutritional status.

Diagnosis relies on history of radiation to the region and clinical evidence of exposed necrotic bone persisting for months; imaging helps define extent and exclude recurrent tumor. Biopsy is reserved for uncertain cases.

Prevention is key, with dental evaluation before radiotherapy and good oral care after treatment. Initial management is conservative: antibiotics for infection, oral hygiene, analgesia, and local wound care. Hyperbaric oxygen therapy is used in some settings but evidence is mixed. Refractory disease may require surgical resection with reconstruction. Prognosis depends on extent, comorbidity, and response to therapy.