Predictive factors of osteoradionecrosis necessitating segmental mandibulectomy: A descriptive study.

[OBJECTIVE] The objective of this study was to assess characteristics of patients with mandibular osteoradionecrosis (ORN) of severity necessitating segmental mandibulectomy and osteocutaneous free flap reconstruction.

[STUDY DESIGN] This study is a retrospective review of patients who underwent free flap reconstruction of the mandible at the UCLA Medical Center between January 2016 and February 2020 secondary to ORN.

[RESULTS] Twenty-nine charts with detailed dental and medical records were identified. Hypertension was reported in 14 of 29 patients, diabetes in 2 of 29, osteoporosis in 2 of 29, antiresorptive use in 3 of 29, tobacco use in 15 of 29, and alcohol use in 19 of 29. Twenty-three patients initially had stage III-IV cancer. The median radiation dose was 68 Gy and median time to ORN was 5.2 years. Chemotherapy was given in 21 patients and 4 had previous mandibular surgery. Twelve of 29 patients had surgical procedures identified as the causative factor and 17 of 29 occurred spontaneously. Median decayed, missing, and filled teeth score was 17 and 17 of 29 patients had grade II-IV periodontitis. Periodontitis was present in 8 of 17 of spontaneous and 1 of 12 of surgery cases. Twenty-five of 29 cases occurred in the same oral sextant as the tumor.

[CONCLUSION] Severe ORN occurred at doses >60 Gy in most cases. Location of the primary tumor was predictive of site of ORN and only molars were involved when precipitated by tooth extraction. Risk of ORN persists indefinitely.