Reconstructing complexity: Indications for simultaneous and chimeric free flaps in extensive maxillofacial defects.

Reconstructing complex head and neck defects using multiple simultaneous or chimeric microvascular free flaps is rare, with no established guidelines on indications. This study evaluates the indications, flap combinations, outcomes, and complications associated with these techniques in maxillofacial reconstruction. A retrospective analysis was conducted on patients who underwent either two simultaneous free flaps or chimeric free flaps for head and neck defects between February 2018 and December 2024. Flap success rates and complication rates were assessed. Twenty-two patients received simultaneous free flaps, with a flap-level success rate of 91 % and a complication rate of 55 %. The most common combination was a fibula free flap with an anterolateral thigh flap. Thirty-six patients underwent chimeric flap reconstruction, achieving a success rate of 94 % and a complication rate of 39 %. Indications for these reconstructions fell into three broad categories: extensive composite defects, complex extraoral defects requiring additional bone reconstruction, and defects involving compromised tissues due to prior radiotherapy or multiple surgeries. Chimeric flaps are a viable option for addressing complex defects in more vulnerable patients, while simultaneous free flaps are feasible for selected cases. Despite acceptable success rates, the elevated complication risks associated with simultaneous flaps necessitate vigilant postoperative monitoring.