RESUMEN
PURPOSE: There is considerable controversy over the treatment of medication-related osteonecrosis of the jaw (MRONJ) and growing interest and debate related to the timing, type, technique, and goals of surgical intervention. The specific aim was to evaluate the predictive value of fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) on healing outcomes in patients undergoing surgery for MRONJ of the mandible. MATERIALS AND METHODS: A retrospective cohort study of 31 patients with 33 MRONJ lesions of the mandible who had undergone surgery using FDG PET-CT was conducted. Data were collected on FDG uptake patterns, healing, follow-up, demographics, lesion characteristics, antiresorptive therapy, and adjunctive therapy. Panoramic and/or periapical radiographs were used to identify non-restorable teeth and PET-CT images were used to identify sequestra and FDG uptake. Above the mandibular canal, surgery consisted of marginal resection and/or debridement of clinically involved bone and exposure of clinically uninvolved bone identified by FDG uptake. Below the mandibular canal, mobile segments of bony sequestra were removed, but areas of clinically uninvolved bone with FDG uptake were not. Patients who did not heal underwent segmental resection and reconstruction with rigid fixation and a local or regional soft tissue flap or free fibular flap. The primary predictor variable was the FDG uptake pattern for each patient. The outcome variable was postoperative healing defined by mucosal closure without signs of infection or exposed bone at the time of evaluation. RESULTS: Two risk groups were identified based on FDG uptake pattern. The low-risk group, type A, included 22 patients with activity limited to the alveolus, torus, and/or basal bone superior to the mandibular canal. The high-risk group, type B, included 11 patients with type A FDG activity with extension inferior to the mandibular canal. Treatment of type A MRONJ lesions was more successful than treatment of type B MRONJ lesions (100 vs 27%; P < .001). Seven of the type B failures were successfully retreated by segmental resection and reconstruction (1 patient refused further treatment). CONCLUSION: These results showed that low-risk FDG PET-CT findings predicted successful healing with surgery above the mandibular canal. In contrast, high-risk FDG findings were associated with a greater than 50% risk of failure for treatment that extended below the mandibular canal. Although these failures suggest that FDG uptake indicates infected tissue, further research is needed to identify which high-risk patients are most likely to benefit from a conservative treatment protocol.