Prefabrication and free transfer of a tissue engineered composite flap - An experimental model in the rat

The technique of flap-prefabrication has been successfully established in tissue engineering: missing intrinsic vascularisation of engineered tissue can be generated in vivo by microsurgical vesselloop construction. It is possible to move engineered tissue into a defect with microsurgery. In the literature, the combination of engineered tissue covered with skin is not widely reported.

Aim of this study was to establish a model to investigate scaffold prefabrication with full thickness skin graft coverage with subsequent free tissue transfer.

8 Wistar rats were operated in 2 separate steps: 1) after creating an arteriovenous loop with the femoral vessels, a porous scaffold was placed on the loop and covered with an inguinally based skin flap. A control was implanted without loop into the contralateral groin. 2) 6 weeks later the prefabricated composite flaps were microsurgically transferred to the cervical region. Skin-island monitoring was performed with Laser Doppler-scanner after the transfer.

Continuous loss of the skin islands was observed within 72 hours. Complications included wound-dehiscence, thrombosis and death from anaesthesia; in spite of consistent loop viability.

Evaluation showed that modifications are necessary to maintain the skin-island cove.