REINNERVATION AND NEOVASCULARIZATION IN PREFABRICATED FREE MUSCLE FLAPS

In this study, immediate muscle reinnervation in flap prefabrication w as investigated and compared with those flaps which were reinnervated after prefabrication. Using the flow-through wrap-around technique for neovascularisation, denervated external abdominal oblique random musc le flaps in Lewis rats were either immediately reinnervated by implant ation of the epigastric nerve or reinnervated late after free transfer , following the prefabrication period of 15 days, Half of the flaps fr om each group were microsurgically transferred to isogeneic rats. Thir ty days later, the flaps were harvested, and neovascularisation and re innervation were studied with microangiography and immunohistochemistr y using antibodies to protein gene peptide (PGP) 9.5, calcitonin gene- related peptide (CGRP), and von Willebrand factor (VWF). Microangiogra phy and quantification of the vWf-stained vessels in the flaps confirm ed increased neovascularisation over a longer time course, Reinnervati on was found to have no influence over neovascularisation, Nerve sprou ting was present 15 days after nerve implantation to the muscle and be came widespread by 30 days, CGRP immunoreactivity, which is thought to have some role in trophic and regulatory processes, was observed only after 30 days of reinnervation. Regardless of the timing and extent o f reinnervation, a considerable amount of muscle atrophy was observed in the flaps. (C) 1995 Wiley-Liss, Inc.