Simultaneous Reconstruction of Bimaxillary Stage 3 Medication-Related Osteonecrosis of the Jaw Using the Buccal Fat Pad Flap Combined With Submandibular Gland Flap

Reconstruction of bimaxillary stage 3 medication-related osteonecrosis of the jaw (MRONJ) defects remains a significant challenge due to extensive lesions and patients' complex comorbidities. This study reports a case of a female patient with metastatic breast cancer who had received long-term denosumab therapy. A partial maxillectomy was performed, and the defect was closed using the double-layer soft tissue closure technique based on the buccal fat pad (BFP). A segmental mandibulectomy was performed through an extraoral approach, and the defect was reconstructed using the reconstruction plate combined with submandibular gland flap (SMGF). The total operative time was 154 minutes, and the postoperative hospital stay was 8 days. At the 6-month follow-up, the scar extending from the midline of the lower lip to the right submandibular region healed well. The intraoral mucosa of both jaws was intact without dehiscence or fistula. Radiographic examination showed resolution of maxillary sinusitis, no osteolytic changes at the resection margins, stable fixation of the reconstruction plate, and bony bridge formation. No recurrence of MRONJ or progression of the primary malignancy was observed. These findings suggest that the combined use of the BFP flap and SMGF can effectively reconstruct bimaxillary stage 3 MRONJ defects with favorable outcomes.