Differential fibular bone mineral density changes following maxillary versus mandibular reconstruction: a cohort study.

The aim of this study was to compare the changes in fibular bone mineral density (BMD) in flaps used for maxillary and mandibular reconstruction, using quantitative computed tomography (QCT). Patients who underwent jaw reconstruction with a fibula flap at Peking University Hospital of Stomatology between September 2021 and September 2024 were included retrospectively. QCT performed at 1 week, 3, 6, and 12 months postoperatively was used to measure and assess BMD, and corresponding resorption amounts were calculated (percentage decrease in BMD relative to the value at 1 week after surgery). Changes in BMD were compared between flaps used in the mandible and maxilla. A total of 151 patients met the eligibility criteria and were included in this study. At 12 months postoperative, fibular BMD had decreased from 1098.6 ± 62.9 mg/cm3 to 696.6 ± 233.9 mg/cm3 in the maxilla group (P < 0.001) and from 1050.1 ± 138.3 mg/cm3 to 953.7 ± 150.1 mg/cm3 in the mandible group (P < 0.001). Generalized estimating equation analysis demonstrated a significantly faster reduction in fibular BMD in the maxilla group when compared with the mandible group (P < 0.001). Within the first postoperative year, fibular BMD declined more markedly following maxillary reconstruction than mandibular reconstruction. Temporally, BMD in the maxilla group showed a continuous decrease, whereas BMD in the mandible group tended to stabilize from 6 months after surgery. TRIAL REGISTRATION: ChiCTR2300069661 (March 22, 2023).