Objectives. The objectives of this study are firstly, to investigate the vascularisation of bioengineered acellular dermal replacement (IntegraTM) in a rat model; and subsequently to effect the microsurgical transfer of the neovascularised “IntegraTM flap” in the same animal model. The findings of this study will form the foundation for further work on the prefabrication of free flaps, en route to the development of thin “designer flaps”.

Materials and Methods. This study was conducted utilising a rat model in two separate phases: Phase one: Under anaesthesia, the superficial inferior epigastric vessels were isolated and sandwiched within a 20x10mm folded sheet of IntegraTM. In the contralateral groin, a folded sheet of IntegraTM without inlaid vessels acted as a control. Twenty rats were subdivided into 4 groups of 5 rats each which were assessed at 24, 48, 72 and 96 hours respectively for evidence of neovascularisation of the “IntegraTM sandwich”. Assessment was conducted via stained histological sections, plain and intravital microscopy. Phase two: Twenty “IntegraTM flaps” were prefabricated as described in phase one. After a delay period of 96 hours to allow sufficient neovasculation of the dermal replacement, microsurgical free flap transfer was performed. Assessment of flap viability after 72 hours was conducted as per the first phase.

Results. Phase one: The earliest evidence of neovascularisation occurred within 24 hours and was detected on intravital microscopy and on histological examination. There was no evidence of neovascularisation in the controls. Phase two: Free microsurgical transfer of the flaps was successfully concluded with post-transfer flap viability being confirmed on histological examination, plain and intravital microscopy.

Conclusions. Vascularisation of IntegraTM in a rat model has been demonstrated to consistently occur within 24 hours. Microsurgical transfer of the free “IntegraTM flaps” has been performed successfully.