Dual free flap reconstruction: A configuration-based algorithm using parallel and serial designs.

Abstract

In 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 remains limited. We assessed outcomes using a configuration-based algorithm distinguishing parallel and serial designs. From 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. The 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. A configuration-based approach may provide practical considerations for dual free-flap reconstruction in complex extremity defects. Parallel and serial configurations can be selected according to defect geometry and recipient vessel accessibility, allowing flexible flap inset and vascular planning. This framework may help guide flap selection in selected cases requiring dual free-flap reconstruction.