ObjectiveTo investigate the effect of pharmacologic delay with pioglitazone, a peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, on extended perforator flap survival in a rat model. MethodsSeventy male Sprague Dawley rats, weighing 250-300 g, were randomly divided into control group (n=35) and experimental group (n=35). A three-territory flap was made, including two choke zones. Pioglitazone was dissolved in 1.5 mL saline. Oral doses of pioglitazone[10 mg/(kg·d)] was given by gavaged for 5 days in the experimental group, while the same volume of saline was given in the control group at same time point. After 7 days, the flap survival area was measured and angiographic diagnosis was made. The tissue samples were harvested from choke zone Ⅱ for histological study and vascular endothelial growth factor (VEGF) expression detection by immunohistochemical staining. The content of nitric oxide (NO) in choke zones I and Ⅱ was measured at immediate, 1, 3, 5, and 7 days after operation. ResultsThe flap general change of 2 groups was similar. Varying degrees of necrosis occurred with the extension of time in 2 groups. At 7 days after operation, the flap survival rate was 87.73%±3.25% in the experimental group and 76.07%±2.92% in the control group, showing a significant difference (t=-10.338, P=0.000). The number of true anastomosis in choke zones I and Ⅱ was 5.40±1.14 and 3.00±0.71 in the experimental group, and was 3.20±0.84 and 0.80±0.84 in the control group respectively, showing significant differences between the 2 groups (t=-3.479, P=0.008;t=-4.491, P=0.002). The microvessel density and the expression of VEGF in choke zone Ⅱ of experimental group were (33.16±7.73)/mm2 and 4 368.80±458.23, respectively, which were significantly higher than those of control group[(23.29±5.91)/mm2 and 2 241.24±554.43] (t=5.073, P=0.000;t=-14.789, P=0.000). The content of NO in the experimental group were significantly higher than those in the control group at other time points (P<0.05) except for at immediate after operation. ConclusionPharmacologic delay with pioglitazone can improve extended perforator flap viability through increasing ischemia-induced angiogenesis and choke vessels vasodilation in rat models.
Objective To summarize and discuss the key factors affecting the hemodynamics in the distal end of the multi-territory perforator flap, so as to provide a theoretical basis for the follow-up research and clinical application in this field. Methods The related recent literature about multi-territory perforator flaps was extensively reviewed, and the concepts and researches of perforasome, choke vessel zone, arterial super-charge, and venous super-drainage were summarized. Results The multi-territory perforator flap is composed of multiple perforasomes, and there are different types of vascular anastomosis in the choke vessel zones, which have important impacts on the hemodynamics of the flap. In order to ensure the survival of the multi-territory perforator flap, arterial super-charge and venous super-drainage are mainly used in clinical practice. However, no consensus has been reached on the choice of the two techniques. The different distribution of blood vessels in the flap, the number of perforasomes, and the type of vascular anastomosis may be the main reasons for the different results. Conclusion The location, diameter, and axial characteristics of perforators, the number of perforasomes, and the type of vascular anastomosis are the key factors affecting the hemodynamics of the multi-territory perforator flaps, which should be paid attention to in preoperative design and surgical procedure.