Comparison of the effect of delay phenomenon and quercetin application on the viability of dorsal island flaps in rats

Introduction: Flaps are tissue units that are transferred from the recipient area to the donor area with their blood supply. Flaps can be classified according to their composition (cutaneous, musculocutaneous, fasciocutaneous, osseocutaneous), relationship with the defect (local, regional, remote, free), nature of blood supply (random, axial), and flap movement required to close the defect (advancement, pivot, transposition, and interpolation). The pedicled cutaneous island flaps mentioned here are advanced into the defect from an area close to the defect but not adjacent to it, preserving the flap pedicle and rotating it around the pivot point. Partial flap necrosis is an important complication that negatively affects the surgical outcome, especially in pedicled island flaps used in the reconstruction of complex defects. In preventing this complication, it is necessary to consider the angiosome concept for skin blood supply. According to this concept, the composite unit consisting of the skin and the underlying deep tissue is fed by a single arterial source and its branches. This composite unit is called an angiosome. According to this concept, 40 angiosomes associated with true arterial anastomoses or choke arterial anastomoses have been identified in the human body. Choke arterial anastomoses are vessels that are normally closed between these angiosomes, regulate blood flow, and potentially dilate into true arterial anastomoses after surgical delay. Surgical delay is all surgical interventions performed 7-14 days before separating the flap from its vascular bed and aiming to increase flap survival in pedicled flaps. These interventions ensure dilation of choke arterial anastomoses and neovascularization of the flap, thus reducing flap distal necrosis and therefore increasing flap survival. Quercetin is a flavonoid with antioxidant, anti-inflammatory, antiviral, antiallergic, antithrombotic, antiatherosclerotic, antitumoral, and vasodilator effects. Due to these properties, it is thought that flavonoids may play an effective role against cardiovascular diseases and many diseases that are likely to occur as a result of radical-mediated damage. In this study, it was thought that the vasodilatation effect of Quercetin would have a positive effect on flap circulation and may have an effect of increasing flap survival and decreasing the percentage of distal necrosis. Objective: The effect of Quercetin on flap survival through its vasodilator effect on vascular system is unknown. In our study, we hypothesized that Quercetin application in rats performing DCIA (deep circumflex iliac artery) -based dorsal island flap may provide vasodilation on vascular system and have a positive effect on flap survival. It is also aimed to compare the effects of Quercetin application and surgical delay procedure on flap survival and to determine whether Quercetin is as effective as surgical delay procedure on flap survival. For this purpose, the effects of Quercetin application and surgical delay procedure were evaluated comparatively macroscopically and histopathologically in the dorsal island flap model we applied in rats. Materials and Methods: In this experimental study, a total of 32 adult male Wistar-type rats weighing 300-350 g were randomly divided into 4 groups, with 8 rats in each group. Group 1 was determined as the control group, Group 2 as the surgical V delay group, Group 3 as the Quercetin group, and Group 4 as the surgical delay + Quercetin group. After preserving the DCIA-based pedicle from the right lateral dorsum of the rats in Group 1 and elevating the flap as an island flap, the flap was re sutured in its place and SF was administered intraperitoneally (IP) for 1 week. After 50 mg/kg IP Quercetin was administered to the rats in Group 3 1 hour before flap elevation, the flaps were elevated in the same way and sutured back into place, and Quercetin application was completed within 1 week. For the surgical delay in the rats in Group 2, the skin on the DCIA perforator side was protected and incisions were made on the other 3 edges around the flap. During the incision on the caudal side of the flap, the thoracodorsal artery was visualized and ligated. The incisions were re sutured. After a 1-week surgical delay, the flaps were elevated over the DCIA perforator and sutured back into place. After flap elevation, IP SF application was performed for 1 week. After surgical delay was applied to the rats in Group 4 in the same way and after waiting for a surgical delay period of 1 week, 50 mg/kg Quercetin was administered to the rats intraperitoneally 1 hour before flap elevation, and then flap elevation was performed and the flaps were sutured back into place. Quercetin application was completed for 1 week at the same dose. In all groups, the necrosis rates of the flaps were evaluated macroscopically at the end of 1 week after flap elevation and the flap necrosis percentages were calculated. Samples were taken from the flaps and examined histopathologically. Histopathologically, vessels larger than 0.1 mm and vessels with congestion were counted. Additionally, evaluations were made in terms of inflammation score, epidermal damage score, and dermal fibrosis score. Vessel lumen diameters were measured in terms of vascular dilatation. Results: It was found that there was a statistically significant decrease in macroscopic distal necrosis rates in the Quercetin-applied groups and the surgical delay groups. When the group in which only Quercetin was applied and the groups in which only surgical delay was applied were compared, it was found that the decrease in the rate of distal necrosis was greater in the group in which only Quercetin was applied and this difference was statistically significant; However, the difference between the Quercetin-only group and the Quercetin+surgical delay group was not statistically significant. When the vasodilatation effect was evaluated, it was found that Quercetin and surgical delay applications provided a statistically significant increase in vascular lumen diameter, but the difference between Quercetin application and surgical delay was not statistically significant. Additionally, the decrease in inflammation, epidermal damage, and dermal fibrosis in the Quercetin-applied groups was also found to be statistically significant. No statistically significant difference was found in terms of the number of vessels and the number of congested vessels in the transition zones between necrosis and the most distal viable flap tissue. Conclusion: As a result, it was observed that Quercetin application in the DCIA-based dorsal island flap model in rats had a positive effect on flap survival, as in the surgical delay application that has been used safely for many years. It had the effect of reducing distal necrosis rates in the flaps by providing vasodilation, reducing inflammation, epidermal damage, and dermal fibrosis. In this study, Quercetin had a greater effect on reducing distal necrosis rates in flaps than surgical delay; However, no difference was found between Quercetin and surgical delay applications in terms of vasodilator effect. Key Words: Island Flap, Surgical Delay, Flap Survival, Quercetin