A preliminary study of the hemodynamics of concealed perforator flap in animal model with ultrasonic Doppler technique

Abstract

To study the hemodynamic characteristics of concealed perforator flap in mini-pigs by ultrasonic Doppler technique. Seven 7-month-old mini-pigs, weighing 20-25 kg, were included in the study. The saphenous artery perforator flap (group A, n=4), saphenous artery concealed perforator flap (group B, n=5), and saphenous artery concealed perforator flap combined with sarcolemma (group C, n=5) models were established randomly on both hind limbs of pigs. The pigs and flap survival conditions were observed after operation. The percentage of flap survival area was calculated by Photoshop CS5 software at 5 days after operation. Ultrasonic Doppler technique was performed on the flaps before operation and at immediate, 3 days, and 5 days after operation to record the hemodynamic changes of the flaps. The hemodynamic indicators of saphenous artery (inner diameter, peak systoli velocity, resistance index, and blood flow) and saphenous vein (inner diameter, maximum velocity, and blood flow) were recorded. At 1 day after operation, 1 pig died of infection, and the rest survived until the experiment was completed. Finally, the 3 flaps of group A, 4 of group B, and 5 of group C were included in the study. The flaps of the 3 groups all showed swelling after operation, which was most significant at 3 days. At 3 days after operation, the flaps in group B showed partial bruising and necrosis. At 5 days after operation, the flaps in groups A and C were basically alive, and the necrosis area of flap in group B increased further. The percentage of flap survival area in groups A, B, and C were 99.7%±0.5%, 74.8%±26.4%, and 100%, respectively. The percentage of flap was significantly lower in group B than in groups A and C (P<0.05). There was no significant difference between groups A and C (P>0.05). There were significant differences in the hemodynamic indicators of saphenous artery and vein between different time points in 3 groups (P<0.05). There was no significant difference in each indicator between groups at each time point (P>0.05). Both the saphenous artery concealed perforator flap and the flap combined with sarcolemma have stable blood flow, but the survival area of the latter was better than the former.