Survival Of Random-pattern Flaps Research Articles

Effect of adipose tissue-derived stromal vascular fraction on the viability of random-pattern skin flaps: an experimental study

Aims: Random pattern skin flaps are still widely used in plastic surgery. However, necrosis in distal flap sections resulting from ischemia is a serious problem, increasing the cost of treatment and hospitalization. The aim of this study was to test the effects of adipose tissue derived stromal vascular fraction (SVF) on random pattern skin flaps in rats. Methods: In this experimental study conducted on Wistar rats, three groups were formed using the simple random sampling technique. Group 1 consisted of rats with a raised flap and a subcutaneous SVF injection. Group 2 comprised rats that underwent a flap operation with no additional treatment. Group 3 included rats with a raised flap and a subcutaneous saline injection. Tissue necrosis and level of survival area was detected with planimetric method and histopathologic examination was performed for detect of level of vascular density. On the 7th day post-operation, the viability assessment was calculated based on the ratio of the living flap area to the total flap area. Results: The mean viability rate in Group 1 was higher compared to other groups, while there was no significant difference between Group 2 and Group 3 (Group 1 = 79.2 ± 4.9 % vs. Group 2 = 41.0 ± 5.9 % vs. Group 3= 39.2 ± 2.7 %, p < 0.001). The mean vascular densities of the flaps were higher in Group 1 compared to the other groups, while it were similar between Group 2 and Group 3 (Group 1 = 29.8 ± 1.2 vs. Group 2 = 8.4 ± 4.6 vs. Group 3= 9.3 ± 1.8, p < 0.001). Conclusion: The use of fat tissue-derived SVF injections has been found to be advantageous in improving the survival of random pattern flaps, frequently utilized in plastic and reconstructive surgery.

Intravenous Infusion of Mesenchymal Stem Cells Promotes the Survival of Random Pattern Flaps in Rats.

Surgical reconstruction options of soft-tissue defects often include random pattern skin flaps. Flap survival depends on flap size and rotation arc and can be challenging regarding flap perfusion, leading to wound healing complications, insufficient wound coverage, and even flap loss. Therefore, novel approaches that promote skin flap survival are required. Bone marrow-derived mesenchymal stem cells intravenous infusion is therapeutically effective in various experimental disease models by means of multimodal and orchestrated mechanisms including anti-inflammatory and immunomodulatory effects, and by means of microvasculature reestablishment. A modified McFarlane-type rodent skin flap model was used. After skin flap surgery, intravenous infusion of mesenchymal stem cells or vehicle was performed. In vivo optical near-infrared imaging using indocyanine green was performed, followed by histologic analysis, including hematoxylin and eosin and Masson trichrome staining, and gene expression analysis. The flap survival area was greater in the mesenchymal stem cell group. In vivo optical near-infrared perfusion imaging analysis suggested that skin blood perfusion was greater in the mesenchymal stem cell group. Ex vivo histologic analysis demonstrated that the skin structure was more clearly observed in the mesenchymal stem cell group. The dermal thickness was greater in the mesenchymal stem cell group, according to the Masson trichrome staining results. The authors observed a higher expression of fibroblast growth factor 2 mRNA in the tissues of the mesenchymal stem cell group using quantitative reverse-transcription polymerase chain reaction. These results suggest that intravenous infusion of bone marrow-derived mesenchymal stem cells promotes skin survival of random pattern flaps, which is associated with increased blood perfusion and higher expression of fibroblast growth factor 2.

The effect of different modes of microneedling technique on random flap survival in rats

The investigation and practice of physical therapy in flap surgery are still scare. The purpose of this study is to evaluate the impact of different microneedling interventions on survival of random pattern flaps in rats, attempting to determine the optimal microneedling protocols for improvement of flap survival. Eighty male Sprague-Dawley rats were randomly divided into four groups, with 20 in each group (group A, B, C, and D). A 3 cm×9 cm rectangular random flap as the McFarlane flap was adopted in each group. In groups A and B, microneedling treatment was performed before and after surgery, respectively. While animals in group C were received both pre- and postoperative microneedling treatment. Group D was used as a control group, which was only exposed to surgery. Flap survival, flap blood flow, number of capillary formations, the expressions of CD31, CD34, HIF-1α, and vascular endothelial growth factor (VEGF) were detected in each group and compared. On the 7th day postoperatively, significant improvements with microneedling treatment were found in flap survival rate (p = 0.007), blood flow (p = 0.024), the expression levels of CD34 (p = 0.005), and the VEGF (p<0.01). Furthermore, the VEGF expression level was significantly higher in group B when compared with the other three groups (all p<0.01). However, there was no significant difference in the number of new blood vessels and other immunohistochemical indicators among the four groups (all p>0.05). Microneedling treatment especially postoperative intervention can significantly improve the survival of random flaps in rats.

The Effect of TENS on Random Pattern Flap Survival in Nicotinized Rats

The adverse effects of cigarettes, due to their nicotine content, may cause important ischemic complications in flaps. Electrical stimulation increases blood flow in ischemic tissues, the level of vascular endothelial growth factor, capillary density, and angiogenesis while decreasing oxygen tension in tissues. Electrical stimulation is also known to increase survival rate in flaps. In this study, which tests the hypothesis that TENS (a type of electrical stimulation) contributes to enhancement of flap viability by eliminating the adverse effects of nicotine, 40 rats were divided into 4 groups of 10 rats. Nicotinization was achieved by subcutaneous administration of 2 mg/kg per day to the rats, other than those in the Control group, for 4 weeks. The rats in one of the nicotinized groups received 20 mA, 80 Hz TENS (TENS1 group) for 1 hour daily throughout the last week before McFarlane flaps of random pattern were made in the backs of all the rats. Another nicotinized group was subjected to TENS in a similar dose after flap elevation (TENS2 group). Flap blood flow was measured before and 48 hours after their construction, and their fluorescein perfusion was measured immediately after the flap elevation. The comparison of the survival rates of the flaps revealed that, although the blood flow in the Nicotine group was significantly lower than in the Control group, it was significantly higher in the TENS1 group than in both the Control and Nicotine groups. The proportion of the area stained with fluorescein, immediately after the elevation of flaps, was significantly reduced in the Nicotine group compared to the Control group. In the TENS1 group, however, it was greater than in the nicotine and TENS2 groups. Flap viability rates decreased significantly in the Nicotine group compared with the Control group. In the TENS2 group, however, an increase was observed compared with the Nicotine group.These findings suggest that although TENS performed before flap elevation does not contribute to flap survival, despite causing a rise in blood flow, it enhances flap survival when applied postoperatively. Given the practicality and low cost of TENS, it can be concluded that it may be possible to use it in the management of ischemic complications in flap operations in smokers.

Vascular endothelial growth factor gene therapy with intramuscular injections of plasmid DNA enhances the survival of random pattern flaps in a rat model

The objective of this study was to determine the effects of the naked plasmid DNA encoding vascular endothelial growth factor (VEGF) on the survival of random flaps on rats. Thirty Sprague-Dawley rats whose random flaps were elevated on the back were randomised into three groups of 10 animals each. In the experimental group, the naked plasmid DNA encoding VEGF was injected directly into the panniculus carnosus of the flap. In the two control groups, either control plasmid DNA or physiologic saline was injected. After 7 days, the flaps were evaluated with the following devices: RT-PCR for the expression of VEGF gene, immunohistochemistry for the expression of VEGF protein, histology for vascular density, single photon emission computerised tomography for RBC in the flap, and image analysis for flap survival area. Notably increased expressions of VEGF mRNA and VEGF protein were found in the treatment group. Vascular density was markedly more increased in the treatment group than those in the two control groups (P < 0.01). Compared with the two control groups, the flap treated with VEGF plasmid DNA showed a more significantly enhanced tissue viability: 87 +/- 5 versus 47 +/- 6% for the control plasmid DNA group and 46 +/- 5% for the saline group (P < 0.01). Our results indicated that the VEGF gene therapy was able to enhance the survival of random pattern flaps by inducing angiogenesis.

Effect of high dose and low dose aspirin on survival of random pattern flaps in rats.

This paper studies which of the physiological effects of aspirin is responsible for increasing the survival of random flaps in rats, found in an earlier experiment. We wished to confirm that the antiaggregating--antithrombotic effect was responsible for the increased survival of flaps without microvascular anastomosis. Three groups of rats with standardised random pattern flaps were used. The first two were given aspirin 200 mg/kg (high dose, n = 27) or 40 mg/kg (low dose, n = 21) and the third (n = 28) acted as controls. The beneficial effects of aspirin were restricted to the high dose group. Since the low dose group also showed antiaggregation of platelets, but without the anti-inflammatory or vasodilatory effects, the results indicate that the antiaggregating effect alone was not responsible for the increased survival of the flaps.

Effect of aspirin on random pattern flap survival in rats

Aspirin is known to increase dermal perfusion and is commonly used to enhance anastomotic patency in microvascular surgery. However, we were unable to find any reports of an effect of aspirin on simple flap survival. In order to determine its effect on flap survival, a controlled experiment was designed using random pattern flaps in rats. The results indicate a statistically significant increase in flap survival in rats receiving aspirin. It is suggested that aspirin’s anti-aggregation effect, in combination with its vasodilatational and anti-inflammatory effect, increases the perfusion in the initial critical hours and thus secondarily decreases the reperfusion injury.

The effect of Prostacyclin on experimental random pattern flaps in the rat.

Abstract In a controlled experimental study of the survival of random pattern flaps in rats it has been found that pre-treatment with prostacylin prior to raising the skin flaps did not improve flap survival. However, if treatment was begun at the commencement of the operation and continued afterwards, there was a significant improvement in flap survival compared with the viability predicted by intravital dye injection. Possible explanations of these findings are discussed and the suggestion put forward that in addition to reducing platelet adherence and vasoconstriction PGI 2 may also stimulate the formation of new capillaries in ischaemic areas. This hypothesis requires further investigation.

The effect of prostacyclin on experimental random pattern flaps in the rat

In a controlled experimental study of the survival of random pattern flaps in rats it has been found that pre-treatment with prostacylin prior to raising the skin flaps did not improve flap survival. However, if treatment was begun at the commencement of the operation and continued afterwards, there was a significant improvement in flap survival compared with the viability predicted by intravital dye injection. Possible explanations of these findings are discussed and the suggestion put forward that in addition to reducing platelet adherence and vasoconstriction PGI 2 may also stimulate the formation of new capillaries in ischaemic areas. This hypothesis requires further investigation.

Lack of effect of isoxsuprine on experimental random flaps in the rat.

Using 1.5 x 6 cm caudally based rat dorsal pedicled flaps, the effect of isoxsuprine on skin flap survival was studied. The results showed isoxsuprine to have no augmentation effect on the survival of random pattern flaps.