Microvascular reconstruction of medication related osteonecrosis of the head and neck

Background: Medication related osteonecrosis of the jaw (MRONJ) requiring free flap (FF) reconstruction is uncommon with limited reported findings. Methods: Multicenter, retrospective case series of 49 consecutive adult patients presenting with advanced MRONJ requiring FF reconstruction from 2010 to 2022. Perioperative complications and outcomes were analyzed. Results: Eighty-two percent (n = 40) of cases were of the mandible and 18% (n = 9) were of the maxilla. The mean follow-up was 15 months (±19.6). The majority of FF survived (96%, n = 47). FF reconstructions of the maxilla were more likely to require postoperative debridement (56%, 95% CI [27, 81%] vs. 15%, 95% CI [7, 25%], p = 0.008) or develop intraoral bone exposure (56%, 95% CI [27, 81%] vs. 18%, 95% CI [9, 27%], p = 0.02). Most patients (71%, n = 35) received preoperative antibiotics which was associated with a higher rate of FF survival (100% vs. 86%, 95% CI [60, 96%], p = 0.02) and fewer complications. Conclusions: Patients undergoing FF reconstruction for MRONJ do well with high rates of FF success. MRONJ of the maxilla have a higher rate of some complications. Preoperative antibiotics correlated with higher FF survival and fewer postoperative complications.