Dual Free Flap Reconstruction: A Configuration-Based Algorithm Using Parallel and Serial Designs

BackgroundIn severe trauma, extensive or geometrically complex soft-tissue defects often exceed the capacity of a single free flap. Dual free flaps offer a versatile solution, yet guidance on flap choice and configuration is inconsistent. We assessed outcomes using a configuration-based algorithm distinguishing parallel and serial designs.MethodsFrom January 2015 to July 2025, 32 patients at two centers underwent dual free-flap reconstruction for wide or elongated defects, predominantly in the setting of trauma. Flap selection was guided by defect geometry and recipient-vessel accessibility: parallel configurations were used for wide defects (first flap to the main recipient vessel, second flap to the serratus anterior branch of the thoracodorsal system), whereas serial configurations were applied for elongated defects (first flap to proximal inflow, second flap to the distal descending branch of the lateral circumflex femoral artery). Patient characteristics, flap types and dimensions, complications, and clinical outcomes were analyzed.ResultsThe mean age was 51.1 years, and trauma was the most common etiology (43.8%). Parallel configurations were used in 27 cases (84.4%) and serial configurations in 5 (15.6%). The mean surface areas of the first and second flaps were 281.7 ± 134.9 cm2 and 247.9 ± 179.0 cm2, respectively, with a total reconstructed area of 529.6 ± 241.0 cm2. Partial flap loss occurred in 4 patients (12.5%), while 28 patients (87.5%) recovered without major complications. Representative cases demonstrated successful reconstruction of complex defects with stable soft-tissue coverage.ConclusionsA configuration-based approach provides a practical and reproducible framework for dual free-flap reconstruction in complex extremity defects. Parallel and serial designs complement each other by matching defect geometry and vessel accessibility, enabling reliable perfusion and efficient operative planning. This algorithm supports clinical decision-making and may expand the role of dual free flaps in trauma reconstruction.