Skin Flap Viability Research Articles

The Effect of Atorvastatin on the Viability of Ischemic Skin Flaps in Diabetic Rats.

Endothelial progenitor cells play a critical role in neovascularization. However, the mobilization, recruitment, and functional capacity of endothelial progenitor cells are significantly impaired in diabetes. Statins have been shown to augment the number and improve the function of endothelial progenitor cells. This study investigated the effects of statins on the viability of ischemic skin flaps in diabetic rats. Twenty normal and 40 diabetic Sprague-Dawley rats were included in this study. Atorvastatin (10 mg/kg/day) was administered orally in 20 diabetic rats at 2 weeks before flap surgery for 21 consecutive days. Other rats received equal vehicle. Two weeks after first gavage, a 3 × 10-cm skin flap was established on the backs of rats. The necrotic area of each skin flap was measured at 7 days postoperatively. Capillary density and endothelial progenitor cells recruited to the flaps were analyzed using immunofluorescence staining. Circulating endothelial progenitor cell number was determined by flow cytometry. In vitro migration and tube formation experiments were used to analyze the function of endothelial progenitor cells. Atorvastatin treatment increased flap survival rate and capillary density. In addition, more endothelial progenitor cells were identified in peripheral blood and skin flaps in diabetic rats receiving atorvastatin. Atorvastatin treatment also restored the impaired function of diabetic endothelial progenitor cells in migration and tube formation. Atorvastatin notably promoted neovascularization and enhanced the viability of ischemic skin flaps in diabetic rats, which may be mediated at least partially by augmenting the number and restoring the functional capacity of endothelial progenitor cells.

Accurate Prediction of Tissue Viability at Postoperative Day 7 Using Only Two Intraoperative Subsecond Near-Infrared Fluorescence Images.

The ability to predict the future viability of tissue while still in the operating room and able to intervene would have a major impact on patient outcome. Although several objective methods to evaluate tissue perfusion have been reported, none to date has sufficient accuracy. In eight Sprague-Dawley rats, reverse McFarlane dorsal skin flaps were created. Continuous near-infrared fluorescence angiography using indocyanine green was performed immediately after surgery, for a total of 30 minutes. These dynamic measurements were used to quantify indocyanine green biodistribution and clearance, and to develop a simple metric that accurately predicted tissue viability at postoperative day 7. The new metric was compared to previously described metrics. Reproducible patterns of indocyanine green biodistribution and clearance from the flap permitted quantitative metrics to be developed for predicting flap viability at postoperative day 7. Previously described metrics, which set the boundary between healthy and necrotic tissue as either 17 or 25 percent of peak near-infrared fluorescence at 2 minutes after indocyanine green injection, underestimated the area of necrosis by 75 and 48 percent, respectively. Our data suggest that both the shape and area of clinical necrosis occurring at postoperative day 7 can be predicted intraoperatively, with the boundary defined as near-infrared fluorescence intensities of 40 to 55 percent of peak fluorescence measured at 5 minutes. Two 750-msec intraoperative near-infrared fluorescence images obtained at time 0 and at 5 minutes after injection of indocyanine green accurately predicted skin flap viability 7 days after surgery.

Non-invasive terahertz imaging of tissue water content for flap viability assessment

Accurate and early prediction of tissue viability is the most significant determinant of tissue flap survival in reconstructive surgery. Perturbation in tissue water content (TWC) is a generic component of the tissue response to such surgeries, and, therefore, may be an important diagnostic target for assessing the extent of flap viability in vivo. We have previously shown that reflective terahertz (THz) imaging, a non-ionizing technique, can generate spatially resolved maps of TWC in superficial soft tissues, such as cornea and wounds, on the order of minutes. Herein, we report the first in vivo pilot study to investigate the utility of reflective THz TWC imaging for early assessment of skin flap viability. We obtained longitudinal visible and reflective THz imagery comparing 3 bipedicled flaps (i.e. survival model) and 3 fully excised flaps (i.e. failure model) in the dorsal skin of rats over a postoperative period of 7 days. While visual differences between both models manifested 48 hr after surgery, statistically significant (p < 0.05, independent t-test) local differences in TWC contrast were evident in THz flap image sets as early as 24 hr. Excised flaps, histologically confirmed as necrotic, demonstrated a significant, yet localized, reduction in TWC in the flap region compared to non-traumatized skin. In contrast, bipedicled flaps, histologically verified as viable, displayed mostly uniform, unperturbed TWC across the flap tissue. These results indicate the practical potential of THz TWC sensing to accurately predict flap failure 24 hours earlier than clinical examination.

Clinical analysis of 54 cases of large area soft tissue avulsion in the lower limb

ObjectiveTo assess the clinical curative effect of different treatment methods for large area avulsion injury in the lower limb. MethodsBetween January 2010 and December 2013, 54 patients with large area avulsion injury in the lower limb were treated in the trauma center of our hospital, including 34 males and 20 females with a mean age of 35.7 years (range, 16–65 years). The injury mechanism was traffic accident in 44 cases, hitting by heavy objects in 8 cases, and fall from height in 2 cases, involving 31 thighs, 19 legs and 4 feet involved. The sizes of the avulsed wounds ranged from 10 cm × 15 cm to 50 cm × 30 cm. There were 16 cases combined with hemorrhagic shock, 5 with femoral fractures, and 7 with tibiofibula fractures. Averagely the patients were sent to our hospital within 3.5 h (range, 1.5–10 h) after injury. For the 54 patients, three different surgical strategies were performed based on the wound area and condition of the avulsed skin: in Group A, 24 patients were treated by debridement and preservation of subcutaneous vascular network + vertical mattress suture of full thickness skin flap + tube drainage; in Group B, 25 patients were treated by split-thickness skin flap meshing and grafting + vacuum sealing drainage (VSD); and in Group C, the other 5 patients were treated by debridement and VSD at stage I + reattachment of autologous reserved frozen split-thickness skin graft at stage II. ResultsAll the 54 patients recovered and were discharged eventually, without any deaths or amputees. In each group, there were no statistical differences (all p > 0.05) among different injury sites in terms of survival rate and length of hospital stay, except for the infection rate, which was much higher (p = 0.000) at the leg area than that at the thigh (32.54% ± 2.97% vs. 2.32% ± 2.34% in Group A and 50.00% ± 0.00% vs. 0 in Group C) or the foot (50.00% ± 0.00% vs. 0 in Group C). Moreover comparison of the three surgical methods showed a significant different (all p < 0.05) between each other for all the three assessed parameters, i.e. flap survival rate, length of hospital stay, and infection rate. ConclusionTreatment choices for skin avulsion on the lower limb should be based on the viability of the avulsed skin flap and the location of the wound. Proper choice can not only reduce the economic burden caused by using VSD, but also shorten the long hospital stay due to repeated wound dressing change or second stage surgery.

Effects of Combination Therapy with Captopril and Angiotensin II on the Viability of Random-pattern Skin Flaps in Diabetic Rat Model

Effects of Combination Therapy with Captopril and Angiotensin II on the Viability of Random-pattern Skin Flaps in Diabetic Rat Model

Impact of different antithrombotics on the microcirculation and viability of perforator-based ischaemic skin flaps in a small animal model.

The effects of antithrombotic drugs on random and free flap survival have been investigated in the past, but the experimental and clinical results are not in agreement. A perforator-based critical ischaemia model was used to evaluate the effects of different perioperatively administered pharmaceutical agents on tissue ischaemia and to assess the potential additional haemorheological or vasodilative effects of antithrombotics on flap microcirculation. Combined laser Doppler flowmetry and remission spectroscopy revealed an increase in certain microcirculation parameters in most groups in comparison with saline controls, and these changes correlated with flap survival. Clopidogrel and hirudin significantly improved the amount of viable flap tissue in comparison with controls, while unfractioned heparin had a negative effect on flap survival. Low molecular weight heparin, aspirin, pentoxifylline, and hydroxyethyl starch had no impact on the amount of viable flap tissue. A higher complication rate was observed in all experimental groups, but only clopidogrel had a negative impact on the flap viability. Our results add to the body of evidence supporting the conclusion that perioperative antithrombotic treatment improves flap survival. Clopidogrel and hirudin are effective pharmacological agents that significantly increased the viability of perforator-based skin flaps in rats, but at a higher risk of postoperative bleeding.

Effects of Clopidogrel and Low-Molecular-Weight Heparin on Viability of Random Skin Flaps in Rats

Background The viability of skin flaps is critical and greatly affects patient's quality of life. Effects of anticoagulant use on focal skin flap necrosis were explored, administering clopidogrel or low-molecular-weight heparin (LMWH) singly and in combination. Methods Adult male rats ( N = 40) were randomly assigned to one of four equally divided groups, raising a random dorsal flap (10 × 4 cm) on each animal and delivering either no drug (control group) or daily applications of LMWH (4 mg/kg), clopidogrel (20 mg/kg), or both agents (LMWH–Clop) for a 7-day period. Thereafter, area and the percentage of flap necrosis (NP) were individually determined. Results Average NP values were as follows: controls, 51.61%; LMWH, 49.50%; clopidogrel, 27.70%; and LMWH–Clop, 29.71%. Conclusion Clopidogrel significantly enhanced the viability of random skin flap in rats, whereas single-agent LMWH or its combined usage conferred no significant benefits in this setting.

Early detection and differentiation of venous and arterial occlusion in skin flaps using visible diffuse reflectance spectroscopy and autofluorescence spectroscopy.

Our previous preclinical study demonstrated that both visible diffuse reflectance and autofluorescence spectroscopy, each of which yields a different set of physiological information, can predict skin flap viability with high accuracy in a MacFarlane rat dorsal skin flap model. In this report, we further evaluated our technique for the early detection and differentiation of venous occlusion and arterial occlusion in a rat groin flap model. We performed both diffuse reflectance and autofluorescence measurements on the skin flap model and statistically differentiated between flaps with and without occlusions as well as between flaps with venous occlusion and those with arterial occlusion based on these non-invasive optical measurements. Our preliminary results suggested that visible diffuse reflectance and autofluorescence spectroscopy can be potentially used clinically to detect both venous and arterial occlusion and differentiate one from the other accurately at an early time point.

Agrimonia eupatoria L. and Cynara cardunculus L. Water Infusions: Phenolic Profile and Comparison of Antioxidant Activities.

Reactive oxygen species (ROS) are highly considered in the ethiopathogenesis of different pathological conditions because they may cause significant damage to cells and tissues. In this paper, we focused on potential antioxidant properties of two medical plants such as the Agrimonia eupatoria L. and Cynara cardunculus L. Both plants have previously been studied for their pharmacological activities, especially as hepatoprotective and hypoglycemic activities. It has been suggested, that their effects are related to the antioxidant properties of polyphenols, which are dominant compounds of the plants’ extracts. In the present study HPLC-MS analysis of water infusion was performed allowing the identification of several phenolic constituents. Furthermore, antioxidant effects of the two extracts were compared showing higher effects for agrimony extract compared to artichoke. Thus, agrimony was selected for the in vivo study using the skin flap viability model. In conclusion, our results provide evidence that the A. eupatoria extract may be a valuable source of polyphenols to be studied for the future development of supplements useful in the prevention of diseases linked to oxidative stress.

Effects of NecroX-5 on the Survival of a Random Pattern Skin Flap in Mice.

Random skin flaps have been widely used for loss of skin and subcutaneous tissues for thousands of years [1]. Unlike the axial pattern flap, the blood supply of a random pattern flap is based on small unnamed vessels. Most unnamed vessels are part of the subdermal plexus [2]. Partial or complete skin flap necrosis is a common problem encountered postoperatively. Flap necrosis caused by disruption of blood supply within the flap often occurs after the surgery, and requires a secondary operation [1,2].

The Vasodilator Effect of a Cream Containing 10% Menthol and 15% Methyl Salicylate on Random-Pattern Skin Flaps in Rats

BackgroundIt is still difficult to prevent partial or full-thickness flap necrosis. In this study, the effects of a cream containing menthol and methyl salicylate on the viability of randompattern skin flaps were studied.MethodsForty female Sprague-Dawley rats were divided into two equal groups. Caudally based dorsal random-pattern skin flaps were elevated, including the panniculus carnosus. In the study group, 1.5 mL of a cream containing menthol and methyl salicylate was applied to the skin of the flap, and saline solution (0.9%) was used in the control group. Upon completion of the experiment, flap necrosis was analyzed with imaging software and radionuclide scintigraphy. Histopathological measurements were made of the percentage of viable flaps, the number of vessels, and the width of the panniculus carnosus muscle.ResultsAccording to the photographic analysis, the mean viable flap surface area in the study group was larger than that in the control group (P=0.004). According to the scintigrams, no change in radioactivity uptake was seen in the study group (P>0.05). However, a significant decrease was observed in the control group (P=0.006). No statistically significant differences were observed between the groups in terms of the percentage of viable flaps, the number of vessels, or the width of the panniculus carnosus muscle (P>0.05).ConclusionsBased on these results, it is certain that the cream did not reduce the viability of the flaps. Due to its vasodilatory effect, it can be used as a component of the dressing in reconstructive operations where skin perfusion is compromised.

Propionyl-L-Carnitine Enhances Wound Healing and Counteracts Microvascular Endothelial Cell Dysfunction.

BackgroundImpaired wound healing represents a high cost for health care systems. Endothelial dysfunction characterizes dermal microangiopathy and contributes to delayed wound healing and chronic ulcers. Endothelial dysfunction impairs cutaneous microvascular blood flow by inducing an imbalance between vasorelaxation and vasoconstriction as a consequence of reduced nitric oxide (NO) production and the increase of oxidative stress and inflammation. Propionyl-L-carnitine (PLC) is a natural derivative of carnitine that has been reported to ameliorate post-ischemic blood flow recovery.Methods and ResultsWe investigated the effects of PLC in rat skin flap and cutaneous wound healing. A daily oral PLC treatment improved skin flap viability and associated with reactive oxygen species (ROS) reduction, inducible nitric oxide synthase (iNOS) and NO up-regulation, accelerated wound healing and increased capillary density, likely favoring dermal angiogenesis by up-regulation for iNOS, vascular endothelial growth factor (VEGF), placental growth factor (PlGF) and reduction of NADPH-oxidase 4 (Nox4) expression. In serum-deprived human dermal microvascular endothelial cell cultures, PLC ameliorated endothelial dysfunction by increasing iNOS, PlGF, VEGF receptors 1 and 2 expression and NO level. In addition, PLC counteracted serum deprivation-induced impairment of mitochondrial β-oxidation, Nox4 and cellular adhesion molecule (CAM) expression, ROS generation and leukocyte adhesion. Moreover, dermal microvascular endothelial cell dysfunction was prevented by Nox4 inhibition. Interestingly, inhibition of β-oxidation counteracted the beneficial effects of PLC on oxidative stress and endothelial dysfunction.ConclusionPLC treatment improved rat skin flap viability, accelerated wound healing and dermal angiogenesis. The beneficial effects of PLC likely derived from improvement of mitochondrial β-oxidation and reduction of Nox4-mediated oxidative stress and endothelial dysfunction. Antioxidant therapy and pharmacological targeting of endothelial dysfunction may represent a promising tool for the treatment of delayed wound healing or chronic ulcers.

Improved viability of random pattern skin flaps with the use of bone marrow mesenchymal-derived stem cells and chicken embryo extract.

Covering tissue defects using skin flaps is a basic surgical strategy for plastic and reconstructive surgery. The aim of this study was to evaluate the effects of chicken embryo extract (CEE) and bone marrow derived mesenchymal stem cells (BM-MSCs) on random skin flap survival (RSF) in rats. Using chicken embryo extract can be an ideal environment for the growth and proliferation of transplanted cells. Forty albino male Wistar rats were divided into 4 groups; each group consisted of 10 rats. BM-MSCs and CEE were transplanted into subcutaneous tissue in the area, where the flap would be examined. On the 7(th) postoperative day, the survival areas of the flaps were measured by using digital imaging with software assistance, and tissue was collected for evaluation. Survival area was 19.54±2 in the CEE group and 17.90±2 in the CEE/BM-MSC group when compared to the rates of the total skin flaps, which were significantly higher than the control group (13.47±2) (P<0.05). The biomechanical assessment showed a slight difference, although there was no statistically significant difference between the experimental groups and the control group (P>0.05). The findings from this study demonstrated that in operative treatment with BM-MSCs and CEE transplantation could promote flap survival, but the biomechanical parameters were not contrasted with a saline injection.

Effects of ozone pretreatment on viability of random pattern skin flaps in rats

Background: Medical ozone is a chemical agent that consists of three oxygen atoms and has antioxidant, angiogenic and vasodilator effects. This study evaluated the effects of medical ozone pre-treatment on flap survival. Materials and methods: Rats were divided into four groups of 10 rats each and a 9 × 3 cm McFarlane flap was used. Sham group: Neither surgical nor ozone pretreatment was used. Control group: No pretreatment was used after surgery. Preoperative ozone group: Preoperative 1 mg/kg ozone was given intraperitoneally for 7 days. No pretreatment was used after surgery. Postoperative ozone Group: Postoperative 1 mg/kg ozone was given intraperitoneally for 7 days. After postoperative 1 week, all groups were evaluated by surface area measurement, histopathology and electron microscopy. Results: With the experimental McFarlane flap model, the experimental groups had better surface area measurements, along with histopathological and electron microscopic results when compared with the control group. Conclusion: Medical ozone had positive effects on flap survival due to its antioxidant, angiogenic and vasodilator qualities.

Performance of drainage through micropores in the treatment of axillary osmidrosis with subcutaneous trimming

Objective To evaluate the performance of drainage through micropores in the treatment of axillary osmidrosis with subcutaneous trimming. Methods Forty-eight patients with axillary osmidrosis were enrolled in this study, and treated by subcutaneous trimming. After removal of apocrine sweat glands and hair follicles, a scalpel was used to cut several micropores（measuring 3 mm in length）along dermal ridges in skin flaps. Then, drainage was carried out through the micropores. Subsequently, the incisions were sewed up with 3-0 sutures followed by compression bandaging with elastic bandages. Dressings were changed and incisions were examined at 24 hours after operation, and bandages were taken off and skin flap viability was evaluated at 10 days. All the patients were followed for 3 months. Results After treatment, sweating was decreased and axillary odor disappeared in all the patients with a return to normal social activities. No obvious scar formed. Conclusion Drainage through micropores performs well in the treatment of axillary osmidrosis with subcutaneous trimming. Key words: BROMIDROSIS; Drainage; Surgical procedures, minor; Surgical flaps; Drainage through micropores

Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model

Although several studies have demonstrated the effects of low-level laser therapy (LLLT) on skin flap viability, the role of higher doses has been poorly investigated. To investigate the inhibitory effect of the LLLT (λ=670 nm) on the viability of random skin flaps in a rat model using an irradiation energy of 2.79 J at each point. Sixteen Wistar rats were randomly assigned into two groups: sham laser irradiation (n=8); and active laser irradiation (n=8). Animals in the active laser irradiation group were irradiated with a 670 nm diode laser with an energy of 2.79 J/point, a power output 30 mW, a beam area of 0.028 cm(2), an energy density of 100 J/cm(2), an irradiance of 1.07 W/cm(2) for 93 s/point. Irradiation was performed in 12 points in the cranial skin flap portion. The total energy irradiated on the tissue was 33.48 J. The necrotic area was evaluated on postoperative day 7. The sham laser irradiation group presented a mean (± SD) necrotic area of 47.96±3.81%, whereas the active laser irradiation group presented 62.24±7.28%. There was a significant difference in skin-flap necrosis areas between groups (P=0.0002). LLLT (λ=670 nm) increased the necrotic area of random skin flaps in rats when irradiated with an energy of 2.79 J (100 J/cm(2)).

Natural Hirudin Increases Rat Flap Viability by Anti-Inflammation via PARs/p38/NF-κB Pathway.

The present study aimed to evaluate the effect of natural hirudin on rat random skin flap viability and to determine the mechanism. Forty-eight rats were randomly divided into 2 groups. After the dorsal skin flap operation (3 cm × 10 cm in size), subcutaneous injections of 6 ATU hirudin were administered to group H (n = 24) every 12 h, while group C (n = 24) received an equal volume of 0.9% normal saline. Six rats from each group were euthanized 1, 2, 4, and 7 days after the operation. A full skin sample was collected from these rats to measure the p38-mitogen-activated protein kinase (p38-MAPK), phospho-p38- (Pp38-) MAPK, nuclear factor-κB (NF-κB) p65, phosphor-NF-κB (pNF-κB) p65, tumour necrosis factor- (TNF-) α, interleukin- (IL-) 6, and intercellular adhesion molecule- (ICAM-) 1 levels via western blot (WB) assays. The results showed that flap viability was significantly higher in the hirudin-treated group, which showed a reduced inflammatory response compared with the control group. The Pp38/p38, pNF-κB p65/NF-κB p65, TNF-α, IL-6, and ICAM-1 levels in the hirudin-treated group were lower than those in the control group. The results demonstrated that hirudin could improve random skin flap viability and suggested that this effect maybe occurs by blocking the thrombin/proteinase-activated receptors (PARs)/p38/NF-κB signalling pathway, thus decreasing the inflammatory response.

The effects of epinephrine and dobutamine on skin flap viability in rats: A randomized double-blind placebo-controlled study

Intraoperative reduction in arterial pressure may cause hypoperfusion of skin flaps, which may increase the risk of flap failure. There is no international consensus regarding the use of vasoactive or inotropic agents to restore or maintain flap perfusion. The purpose of this study was to evaluate the effects of the intraoperative administration of epinephrine and dobutamine on axial-pattern skin flap survival in rats. Fifty-four Sprague Dawley rats were randomized into three groups (n=18). A tubed axial-pattern skin flap was performed. Animals were randomized to receive an intraperitoneal injection of epinephrine 0.1mg/kg, dobutamine 0.3mg/kg, or saline (0.5ml). The rats were euthanized after 7 days and the viable area of the flap was compared between the groups using a digital imaging and computer software. Seven rats/flaps were excluded from the study due to autocannibalism (n=3), postoperative tracheal obstruction (n=2), anesthesia-induced respiratory arrest (n=1), and abnormal behavior requiring euthanization (n=1). The mean flap survival was 46%±9% in the saline group (n=17), 41%±9% in the epinephrine group (n=14) (p=0.088 compared to the saline group), and 54%±9% in the dobutamine group (n=16) (p=0.02 compared to the saline group and p=0.001 compared to the epinephrine group). Intraoperative intraperitoneal injection of dobutamine improves skin flap survival in rats, whereas intraperitoneal epinephrine tends to decrease skin flap survival.

Improved Random Component Viability of Axial Skin Flap through the Use of Human Adipose Derived Stem Cells

Improved Random Component Viability of Axial Skin Flap through the Use of Human Adipose Derived Stem Cells

Predicting skin flap viability using a new intraoperative tissue oximetry sensor: a feasibility study in pigs.

Operations for soft-tissue reconstruction, orthopedic, vascular, and other types of surgery can be complicated by unexpected skin flap necrosis. At present, surgeons utilize subjective clinical judgment and physical findings to estimate the potential for tissue compromise. As the validity of these subjective methods is questionable, there is a need for objective, quantitative tools to determine the risk of flap necrosis during surgery. Three 9-month-old Yorkshire pigs were used for the study. Four laterally based random pattern fasciocutaneous flaps were dissected on each animal. After the flaps were elevated, a prototype oximeter (ViOptix Inc., Fremont, CA), was used to measure tissue oxygenation (StO2) at 2 cm intervals along the flaps. Measurements were performed immediately after the flaps were dissected, and again at the same points after they were sutured. The animals were reevaluated 4 days later, and assessed for areas of tissue necrosis. For each flap, StO2 at the base was compared with StO2 at the more distal points. The median delta StO2, as measured immediately after dissection, was -3.9% points for tissue that remained viable and -34.0% points for tissue that became necrotic (p = 0.039). After the flaps were sutured back to the chest wall, the median delta StO2 for tissue that remained viable was -1.7% points versus -24.7% points for tissue that became necrotic (p = 0.006). This new handheld surface sensor can be used to measure StO2 of skin flaps and may potentially reduce complications associated with unexpected tissue necrosis.