Morphostructural changes in transferred fasciocutaneous free flaps: a preliminary clinical and immunohistochemical report

Abstract

Many local factors, yet to be investigated, can promote changes in tissue transferred by microsurgical technique into the recipient site. Several studies have attempted to assess the nature of modifications that occur in the vascular network of such a flap after transfer. Although these investigations have interesting conclusions, the majority of them were based only on indirect evaluations. The aim of this study was to detect, by histological and statistical analysis, the morphostructural changes that occurred in fasciocutaneous free flaps transferred to the cephalic region or to the lower limb. Patients were enrolled in this study only when neither local inflammatory reactions nor systemic diseases were observed at the time of biopsy. Six patients consented to undergo biopsy at both the donor and the recipient area of a previously transferred fasciocutaneous free flap. Three flaps were used for facial reconstruction, and three others for lower limb reconstruction. Standard staining and immunohistochemical investigations were performed. The sections were also analysed by specific software. Statistical analysis of the data was performed using the student's t-test and Fisher's test. In five out of six transferred flaps (83%), there was increased microvascularity compared to the donor area. It was correlated to the neoangiogenesis in the dermal layer of the flaps. In five recipient sites there were more new vessels. In particular, a higher score of angiogenesis was observed both in the cheek (one flap) and in the non weight-bearing area of the foot (two flaps) (P<0.001). Some differences in microvascularity between the donor and the recipient site in the same flap were related to the specific recipient site. This represents the first demonstration of adaptation of fasciocutaneous free flaps to the recipient area, as well as to their new function, at both the macroscopic and microscopic level.