Heterogeneity of Necrotic Changes between Cortical and Cancellous Bone in Mandibular Osteoradionecrosis: A Histopathological Analysis of Resection Margin after Segmental Mandibulectomy

BACKGROUND This study aimed to analyze differences in necrotic changes between cortical and cancellous bone in resection margins after segmental mandibulectomy for advanced mandibular osteoradionecrosis. METHODS Anteroposterior bone specimens from eleven patients who underwent segmental mandibulectomy with simultaneous free fibula flap reconstruction for advanced osteoradionecrosis were analyzed histopathologically for the presence of necrotic bone based on the presence of blood vessels within Haversian canals. RESULTS Ten of eleven (91%) cortices near the inferior border of the mandible at the anterior margins were necrotic. All cancellous bones at the anterior margins were viable. Seven of eleven (64%) cortices near the inferior border of the mandible at the posterior margins were necrotic. Three of eleven (27%) cancellous bones at the posterior margins were necrotic. CONCLUSION Necrotic changes are more prevalent in cortices than in cancellous bones in mandibular osteoradionecrosis, probably due to a decrease of periosteal blood supply caused by radiotherapy.