Flap-to-flap neovascularization for extended soft-tissue reconstruction of the upper-limb

Extensive upper-limb soft-tissue defects may exceed the surface area achievable with conventional free flaps, making reconstruction challenging when durable coverage and functional preservation are required. We describe a novel reconstructive strategy to extend soft-tissue coverage based on secondary flap-to-flap neovascularization in which a pedicled flap achieves secondary vascular independence through neovascularization from the free flap skin paddle via the subdermal vascular plexus, thereby enabling delayed division without additional microsurgical anastomoses. A 64-year-old man developed necrotizing fasciitis of the right upper limb following an insect bite. After repeated surgical debridements, a massive circumferential forearm defect extending to the elbow was associated with extensive tissue loss of the dorsal hand, first web space, and palm. A 45 × 11 cm chimeric anterolateral thigh-tensor fascia latae (ALT-TFL) free flap was harvested and anastomosed to the radial vessels, providing stable coverage of exposed extensor tendons and neurovascular structures. An ipsilateral pedicled 20 × 15 cm groin flap was inset onto the ALT skin paddle and subsequently divided, defatted, and wrapped around the thumb to recreate the first web space and resurface the palm. At 18-month follow-up, soft-tissue coverage remained stable, with complete flap survival, no recurrence of infection, and good functional recovery. Unlike sequential or conventional free-flap reconstruction, this approach does not require additional arterial inflow or flow-through anastomoses, relying instead on secondary flap-to-flap neovascularization. It may therefore represent a relevant strategy to extend reconstructive coverage beyond conventional flap dimensions in extensive upper-limb defects.