OBJECTIVETo investigate the hemodynamic changes of an over-midline axial flap.

METHODSAn over-midline axial flap, based on the iliac artery and veins, was raised on the back of each selected Wistar rat (n = 30), vascularied by contralateral. The flap size is 7 cm x 3 cm. The over-midline part is 3 cm x 3 cm. A laser doppler flowmetry (LDF) was used to evaluate the hemodynamic changes preoperatively, and 6 hours, 24 hours, 48 hours, 72 hours, 7 days, and 14 days after the operation respectively.

RESULTSAll of the flaps survived well. But, in the first three days after the operation, the blood perfusion of the flap in the areas of the midline and the distal part was significantly lower than the preoperation's level. Thereafter, the values of the blood perfusion started to increase till to the maximum 7 days after the operation. On the 14 days after the operation, the vascular structures was axially matched to the base of the flap. In the distal part of the flap, the choke vessels were gradually opened and resulted in the blood perfusion to the normal level.

CONCLUSIONThe hemodynamic changes of the over-midline axial flap transmidline flap could occur to match the need of the base of the flap.