OBJECTIVETo investigate the influence of over-expansion on the viability and vascularity of an axial-pattern flap.

METHODSTissue expanders were implanted subcutaneously on the buttock of the mini-pig. After over expansion, an axial-pattern over-expanded skin flap was elevated in the pig of the experimental group. The differences in flap survival, LDF, MDA content and fluorescein stain were observed between the control and the experimental groups. The vascular architecture changes were also recorded using histological and clearing specimen examination.

RESULTSThe microcirculation in the distal segment of the axial flap was significantly weakened after over-expansion. There were injury manifestation, change in vessel distribution and reduction of vascular territory in the axial over-expanded flap.

CONCLUSIONSOver-expansion could cause chronic injuries to the axial vessel network and damage the blood supply of the axial-pattern flap.