Dorsal Skin Flap Research Articles

Effect of exogenous L-arginie on survival of extended dorsal perforator flaps in rats

Objective: To investigate the effect of exogenous L-Arg on the survival of extended perforator flap in rats. Methods: Sixteen male Sprague Dawley rats were randomly divided into L-Arg group (n=8) and control group(n=8). The extended dorsal three-vascular territory perforator flaps were made in rats. L-Arg (400 mg·kg-1·d-1) was injected intraperitoneally in L-Arg group 1d before operation, immediately and 1-7 d after operation, while the same volume of saline was injected intraperitoneally in control group at the same time points. The appearance and distribution of blood vessels were observed, and the flap survival areas were measured 7d after operation. The tissue samples were harvested from choke zone Ⅱ for histological study and the expression of vascular endothelial growth factor (VEGF) was detected by immunohistochemistry and Western blot, respectively. Results: After 7d, the clearer vascular structure and more new vessels in choke zone Ⅱ were observed in L-Arg group. The survival rate of flap in L-Arg group was (88.42±4.19)%, which was significantly higher than that in control group[(76.52±5.37)%, t=3.707, P<0.01]. The microvessel density and caliber of choke zone Ⅱ in L-Arg group was (29.47±5.28)/mm2 and(47.27±5.32)μm, which were significantly higher than those in control group (t=2.694 and 2.389, P<0.05 or P<0.01). The immunohistochemistry and Western blot showed that the expression of VEGF in choke zone Ⅱ of L-Arg group was significantly higher than that in control group (t=9.428 and -3.054,P<0.05 or P<0.01). Conclusion: Exogenous L-Arg can increase the survival rate of extended dorsal perforator skin flap through promoting vascularization and dilatation of vessels in choke zone Ⅱ in rats.

Use of Bipedicled Dorsal Penile Flap With Z Release Incision: A New Option in Redo Hypospadias Surgery

To solve the challenge in redo hypospadias surgery, we tried to use a bipedicled dorsal penile flap with a Z release incision in failed hypospadias cases and reported the outcome. Thirty male children with 3 or 4 previous unsuccessful hypospadias surgeries were included in our study. Our technique was done after at least 6 months from the last surgery. A flap of the dorsal penile skin was preserved and the skin lateral to the flap was dissected on each side. A small opening was done in the dartos proximal to flap. The glans was withdrawn through this opening with a ventral transposition of the flap. Z-plasty was used to compensate for the deficient dorsal skin; the Z-plasty had 3 limbs and all were made of equal length. The mean age of the patients was 5.4 ± 1.8 years and the mean follow-up was 2.1 ± 0.7 years. The technique was successful in 80%. Reoperation was required in 3 cases; all cases were managed using a 2-stage buccal mucosal graft. A small fistula at the coronal level developed in 2 cases but closed spontaneously within 1 month. All patients were voiding well and had a vertically oriented meatus at the tip of the glans and satisfactory cosmetic results. Repair of failed hypospadias using a bipedicled dorsal penile skin flap with Z release incision is a safe and simple procedure offering high success rates.

De-epithelialized dorsal digital turnover flap for coverage of volar digital lesions: a modified technique

Volar digital injuries represent a challenge to hand surgeons. Anatomical studies demonstrate the existence of dorsal digital branches of the ulnar and radial arteries at predictable and regular distances from the PIP joint, bilaterally. Moreover, as there are also small veins that accompany the arterial branches, we designed a novel de-epithelialized dorsal finger turnover flap, which can be performed on the ulnar and radial sides of fingers where it is important to maintain the paratenon to support the dorsal skin flap. A 21-year-old female presented with traumatic injury to the middle phalanx of the third finger associated with loss of substance and damage to the flexor tendons in zone II. The dorsal part of the finger was used to provide coverage for a volar injury. There was no scar retraction or functional limitation of the reconstructed finger. This novel, de-epithelialized dorsal finger turnover flap can be safely used for coverage of volar finger lesions, due to a reliable and well-described arterial supply, with no skin necrosis of the donor site, post-surgical infection, or scarring complications. Level of Evidence: Level V, therapeutic study.

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.

Microvascular Fragment Transplantation Improves Rat Dorsal Skin Flap Survival.

Background:The development of flap necrosis distally remains a concern during microsurgical flap transfers because, at least in part, of decreased perfusion. Microvascular fragments (MVFs) are microvessels isolated from adipose tissue that are capable of improving tissue perfusion in a variety of tissue defects. The aim of this study was to determine whether the transplantation of MVFs in a dorsal rat skin flap model can improve flap survival.Methods:A 10 × 3 cm flap was raised in a cranial to caudal fashion on the dorsal side of 16 Lewis rats, with the caudal side remaining intact. The rats were equally divided into a treatment group (MVFs) and a control group (sterile saline). At the time of surgery, sterile saline with or without MVFs was injected directly into the flap. Microvessel density was determined after harvesting flap tissue by counting vessels that positively stained for Griffonia simplicifolia lectin I-isolectin B4. Laser Doppler was used to measure blood flow before and after surgery and 7 and 14 days later. Flap survival was evaluated 7 and 14 days after surgery by evaluating the percentage of viable tissue of the flap with photodigital planimetry.Results:Despite the lack of a significant difference in microvessel density and tissue perfusion, flap survival increased 6.4% (P < 0.05) in MVF-treated animals compared with controls.Conclusions:The use of MVFs may be a means to improve flap survival. Future studies are required to delineate mechanisms whereby this occurs and to further optimize their application.

Effectiveness of improved interosseous dorsal arteryisland flap cutting method to repair of hand trauma

Objective To research the clinical effect of the improved forearm interosseous dorsal flap cutting method to repair hand trauma. Methods Thirty-one cases patients with hand trauma who were treated in Dongfeng Hospital Affiliated to Hubei Medicine University from April 2014 to October 2015 were selected as study objects.Based on the improved interosseous artery after of the forearm interosseous dorsal flap cutting method to repair hand trauma, the skin flap survival after treatment and wound healing was observe. Results (1)Seven days after treatment, 2 cases of volar skin was defected flaps in patients with distal necrosis, and healed after the two phase of skin grafting, all the other flap issue of survival after the first phase, and the wounds were good, but there was 1 cases partial necrosis for skin grafting then healed after expectant treatment.(2)After 3-16 months follow-up, there were 4 cases of skin flap, and the appearance of the skin flap was over, and then the skin flap was repaired.The rest of the flap was good in appearance, and the two point discrimination was 5-8mm.(3)According to a 1994 Zhao Shuqiang improvements such as the luxury institute of Chinese medical association of functional trial evaluation standard of upper limb parts: 29 cases in excellent, 2 cases in good.All patients with hand trauma, skin color, appearance and perception function recovered satisfactorily. Conclusion The improved forearm interosseous dorsal flap cut operation is simple, flap survival situation better and wound healing, at the same time can also repair patients with hand perception function, is a kind of functional repair plan and worth promoting in clinic. Key words: Forearm interosseous dorsal skin flap; Hand trauma; Perceptive function; Functional reparation

Effect of hirudin on promotion of blood supply and angiogenesis in rat ischemic skin flap

Objective To study the effect of hirudin on perfusion and angiogenesis in distal ischemic skin flap. Methods The 35 SD rats, two random dorsal skin flaps were made on individual SD rat and assigned randomly into hirudin group and control group. Hirudin group was injected with 0.5 U hirudin and control group injected with the same amount of saline. The distal flap tissue perfusion, microvessel density (MVD) of flap biopsies and expression of vascular endothelial growth factor (VEGF) and thrombospondin-1 (TSP-1) were detected by a full-field laser perfusion imager, immunohistochemistry and Western blot, respectively. The flap survival areas at day 6 were also measured. Results Compared with control group, hirudin group resulted in enhanced distal flap perfusion on day 1 (P<0.05), higher MVD at day 4 (P<0.05) and significant upregulation of flap VEGF levels during days 1-6 (P<0.05). The expression of TSP-1 in hirudin group was significantly lower at days 1-4 (P<0.05) than that of control group. Larger mean flap survival area was observed in the hirudin group (P<0.05). Conclusions Hirudin improves ischemic skin tissue survival through enhancing the recovery of perfusion, regulating angiogenesis associated factors, and facilitating microvessel formation in ischemic flap. Key words: Hirudin; Random pattern skin flap; Vascular endothelial growth factor; Thrombospondin-1

Effects of insulin-like growth factor-1 on random pattern skin flap survival in rats.

To investigate the effects of pharmacological delay with insulin-like growth factor-1 (IGF-1) on skin flap survival. Thirty Sprague-Dawley rats were submitted to dorsal skin flap (3x9 cm). Seven days before the surgery, the animals were subdivided into three groups of 10 rats. In group 1 (controls), no injection was done. Seven days before the elevation, saline had been injected to the marked skin flap area in group 2 (sham group), and group 3 (experimental group) underwent a pharmacological delay with subcutaneous IGF-1 injections. On the seventh postoperative day, flap area was analyzed for survival. Tissue samples were obtained for histological and biochemical evaluations. Survival rates were 43.55 ± 16%, 21.40 ± 8%, and 43.12 ± 14% in groups 1, 2, and 3, respectively. Differences between group 2 and other groups were statistically significant. No significant difference was detected between all three groups for tissue or plasma vascular endothelial growth factor (VEGF) levels. There was no significant histological difference between groups. Although a single injection of insulin-like growth factor-1 (IGF-1) did not significantly increase flap survival, its wound healing features are still encouraging and further meticulously planned studies, especially with repeated applications or controlled-release methods, and combinations with binding protein are required.

Selection of appropriate pedicle for dorsal skin flap studies on rats

Selection of appropriate pedicle for dorsal skin flap studies on rats

Novel skin chamber for rat ischemic flap studies in regenerative wound repair.

BackgroundIn plastic surgery, skin flap is an important approach to reconstructive wound repairs. The rat dorsal skin flap is a clinically relevant and popular animal model to investigate and evaluate flap survival and necrosis. Nonetheless, flap survival is often unstable with unpredictable outcomes, regardless of previous attempts at design modification.Methods & ResultsIn the present study, we report a novel flap chamber that provides stable and reproducible outcomes by separating the dorsal skin flap from its surrounding skin by in situ immobilization. The flap chamber blocks circulation that disturbs flap ischemia from both basal and lateral sides of the flap tissue. Demarcation of skin necrosis is macroscopically evident on the flap and supported by distinct changes in histological architecture under microscopic examination. The utility of the novel skin flap chamber is further proven by applying it to the examination of flap survival in streptozotocin-induced diabetic rats with an increase in skin necrosis. The flap chamber also affords size modifications where a narrower flap chamber increases ischemia and provides manipulable therapeutic windows for studying cell therapies. Accordingly, intradermal injection of endothelial cells 3 days before flap ischemia significantly increases the survival of skin flaps.ConclusionsThe novel flap chamber not only may stabilize the skin flap and provide reproducible outcomes that overcome the shortfalls of the traditional ischemic flap but also may afford size modifications that support research designs and test therapeutic approaches to regenerative repair.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-016-0333-0) contains supplementary material, which is available to authorized users.

Effects of Silk Sericin on Incision Wound Healing in a Dorsal Skin Flap Wound Healing Rat Model.

BackgroundThe wound healing process is complex and still poorly understood. Sericin is a silk protein synthesized by silk worms (Bombyx mori). The objective of this study was to evaluate in vivo wound healing effects of a sericin-containing gel formulation in an incision wound model in rats.Material/MethodsTwenty-eight Wistar-Albino rats were divided into 4 groups (n=7). No intervention or treatment was applied to the Intact control group. For other groups, a dorsal skin flap (9×3 cm) was drawn and pulled up with sharp dissection. The Sham operated group received no treatment. The Placebo group received placebo gel without sericin applied to the incision area once a day from day 0 to day 9. The Sericin Group 3 received 1% sericin gel applied to the incision area once a day from day 0 to day 9. Hematoxylin and eosin stain was applied for histological analysis and Mallory-Azan staining was applied for histoimmunochemical analysis of antibodies and iNOS (inducible nitric oxide synthase), and desmin was applied to paraffin sections of skin wound specimens. Parameters of oxidative stress were measured in the wound area.ResultsEpidermal thickness and vascularization were increased, and hair root degeneration, edema, cellular infiltration, collagen discoloration, and necrosis were decreased in Sericin group in comparison to the Placebo group and the Sham operated group. Malonyldialdehyde (MDA) levels were decreased, but superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were increased in the sericin group.ConclusionsWe found that sericin had significant positive effects on wound healing and antioxidant activity. Sericin-based formulations can improve healing of incision wounds.

Effect of Hevea brasiliensis latex sap gel on healing of acute skin wounds induced on the back of rats

to evaluate the effect of topical delivery of latex cream-gel in acute cutaneous wounds induced on the back of rats. we subjected sixteen rats to dermo-epidermal excision of a round dorsal skin flap, with 2.5cm diameter. We divided the animals into two groups: Latex Group: application of cream-gel-based latex throughout the wound bed on postoperative days zero, three, six and nine; no treatment on the wound. Photographs of the lesions were taken on the procedure day and on the 6th and 14th postoperative days, for analyzing the area and the larger diameter of the wound. We carried out euthanasia of all animals on the 14th postoperative day, when we resected he dorsal skin and the underlying muscle layer supporting the wound for histopathological study. there was no statistically significant difference in the percentage of wound closure, in the histopathological findings or in the reduction of the area and of the largest diameter of the wounds among the groups studied on the 14th postoperative day. according to the experimental conditions in which the study was conducted, latex cream-gel did not interfere in the healing of acute cutaneous wounds in rats.

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.

Abstract B48: Optical toolbox for in vivo analysis of glucose uptake, vascular oxygenation, and mitochondrial membrane potential in breast cancer

Abstract The goal of this work is development of a fast and repeatable optical assay that uses a novel combination of fluorophores and endogenous contrast to report on the metabolic phenotype of cancers in vivo. The proportions of ATP generated by glycolysis and oxidative phosphorylation relate to inherent tumor behaviors that affect treatment response. The need for instruments measuring metabolic endpoints is demonstrated by the widespread use of Seahorse extracellular flux analyzers in cancer research. The assays provide valuable insight into two primary arms of cellular metabolism by reporting on extracellular acidification rate (ECAR) related to glycolysis and oxygen consumption rate (OCR) related to mitochondrial respiration [1]. The ratio OCR/ECAR obtained by Seahorse was used to compare a panel of breast cancer cell lines and show that basal subtypes were often highly glycolytic, which suggested better therapeutic outcome [2]. While the Seahorse is an excellent research tool, the technique requires special cell preparation and continual testing of cell media, and is therefore not applicable in vivo. Being able to measure both oxidative and glycolytic metabolism in vivo in a repeatable way would aid the identification of appropriate therapies based on tumor phenotype. We developed an in vivo metabolic imaging strategy for use on a dorsal skin flap chamber model and are developing tools to analyze the same endpoints in solid tumors [3-5]. Vascular oxygen saturation (SO2) is calculated using endogenous absorption contrast from oxy- and deoxy- hemoglobins (520-620nm in 10nm increments). Glucose uptake is measured using a fluorescent D-glucose derivative (2-NBDG, Ex/Em 470/525nm). We have previously optimized 2-NBDG imaging [4], and have recently incorporated a fluorescent cationic dye (TMRE, Ex/Em 545/590nm) to report on mitochondrial membrane potential (MMP). Delivery-corrected 2-NBDG was measured 60 minutes post-injection (2-NBDG60/RD) and TMRE was measured 50 minutes post-injection (TMRE50) in dorsal windows containing metastatic (4T1) or non-metastatic (4T07, 67NR) sibling tumor lines. When images were segmented into spatial maps and parsed by regional SO2, phenotypic differences between metastatic and nonmetastatic tumors emerged. To increase the range of SO2, some animals were subject to hypoxia. In 4T1 tumors, glucose uptake decreased significantly (p&amp;lt;0.01 for 0&amp;lt;SO2&amp;lt;10 vs. 40&amp;lt;SO2&amp;lt;60) and MMP increased slightly as SO2 increased. However, in 4T07 and 67NR tumors there is minimal change in glucose uptake or MMP with changes in SO2. Differences in global averages were also apparent. Glucose uptake was significantly increased in 4T1 relative to either 4T07 (p&amp;lt;0.01) or nontumor tissue (p&amp;lt;0.02). Interestingly, glucose uptake was comparable between 4T07 and nontumor. On the other hand, MMP was increased in 67NR (p&amp;lt;0.02) and 4T1 (p&amp;lt;0.01) relative to nontumor, suggesting generally increased oxidative metabolism in tumors. MMP was indistinguishable for 67NR and 4T1. Average SO2 was comparable across groups. Strikingly, the ratio of average glucose uptake/average MMP was 0.45 for metastatic and 0.12 for nonmetastatic tumors. These data indicate the importance of considering both the overall quantity of metabolic demand and the ratio of glycolytic and oxidative metabolism. In conclusion, our data show a shift toward glycolysis in a metastatic relative to a nonmetastatic sibling breast cancer line, demonstrating the potential of our method to identify unique metabolic phenotypes in vivo. Our future efforts focus on transitioning the assay into an optical spectroscopy platform appropriate for long-term monitoring of tumor growth or therapy response. [1] Seahorse Bioscience online [2] Dennison, Clin Cancer Res 2013 [3] Rajaram, PLOS ONE 2013 [4] Frees, PLOS ONE 2014 [5] Rajaram, PLOS ONE 2015 Citation Format: Amy Frees Martinez, Samuel S. McCachren, III, Narasimhan Rajaram, Mark W. Dewhirst, Nimmi Ramanujam. Optical toolbox for in vivo analysis of glucose uptake, vascular oxygenation, and mitochondrial membrane potential in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr B48.

Value of remote ischaemic preconditioning in rat dorsal skin flaps and clamping time

Objective: According to previous reports, remote ischaemic preconditioning (RIPC) is a “delay” procedure that is highly likely to be useful for preventing skin flap necrosis. Differences in the extent of necrosis in rat dorsal skin flaps when different clamping times were used in RIPC were compared among the four groups described below.Methods: Group A was a control group in which no prior ischaemic area was created, and both back legs were devascularised for 15 min in Group B, 30 min in Group C, and 60 min in Group D. The experiments were performed on 10 rats in each group, and the surviving area was measured. One-way analysis of variance (ANOVA) and Tukey’s multiple comparison test were used for analysis, with p < 0.05 regarded as significant.Results: The surviving area of the skin flap was 15.4 ± 1.8 cm2 in Group A, 15.4 ± 2.0 cm2 in Group B, 17.9 ± 2.0 cm2 in Group C, and 19.2 ± 3.4 cm2 in Group D, with significant differences between Groups A and D and between Groups B and D.Conclusions: RIPC consisting of 60 min of ischaemic preconditioning may be clinically useful as a method of preventing skin flap necrosis.

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.

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].

Effects of Kaurenoic Acid and Arginine on Random Skin Flap Oxidative Stress, Inflammation, and Cytokines in Rats.

Kaurenoic acid (KA), a diterpene extracted from copaíba oil-resin, is known to have potent antioxidant and anti-inflammatory properties. L-Arginine (LA) is an amino acid and a nitrogenous precursor for the synthesis of nitric oxide (NO). NO paper in wound healing has already been well documented. The aim of this study was to investigate the protective effects of LA and KA against ischemia reperfusion injury in a randomized skin flap model in rats. A modified McFarlane flap model measuring 2.5 wide × 8 cm long was established in 36 anesthetized rats and evaluated within 3 groups: group control, group L-arginine, and group kaurenoic acid. Each group was subdivided into two subgroups (T1 and T2, n = 6 each). Samples were collected 24 h (T1)/48 h (T2) postoperatively for oxidative stress (glutathione), as non-protein thiols, malondialdehyde (MDA), NO2, inflammation [myeloperoxidase (MPO)], and cytokines TNF-α and IL-1β assays. KA promoted a significant decrease of TNF-α and IL-1 expression and MPO activity at T1/T2 time points. NSGH levels increased significantly in KA-treated rats, while MDA levels decreased significantly in the same rats. Arginine promoted a significant decrease in MDA levels at the T1 time point and a significant increase in non-protein thiols concentrations at T1/T2 time points. NO2 concentration also decreased at the T1 time point. KA may attenuate the oxidative stress and the inflammation, thereby reducing tissue damage induced by ischemia/reperfusion in rats subjected to dorsal skin flaps. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266.

The Effect of Mature Adipocyte-Derived Dedifferentiated Fat (DFAT) Cells on a Dorsal Skin Flap Model

ABSTRACTBackground: Dedifferentiated fat (DFAT) cells, isolated from mature adipose cell, have high proliferative potential and pluripotency. We report on the expansion of flap survival areas on the back of rats administrating DFAT cells. Materials and Methods: Intraperitoneal adipose tissue was collected from a male Sprague-Dawley (SD) rat. The mature fat cells were cultured on the ceiling surface of culture flask to isolate DFAT cells. On day 7 of the culture, the flask was inverted to allow normal adherent culture. A dorsal caudal-based random pattern flap measuring 2 × 9 cm was raised on each SD rat. We prepared a control group (n = 10) and a flap base injection group in which DFAT cells were injected 2 cm from the flap base (n = 10) and a flap center DFAT injection group (n = 10). In which DFAT cells at 1 × 106 cells/0.1 ml were injected beneath the skin muscle layers of the flap. The flap survival areas were assessed on day 14 after surgery. Results: The mean flap survival rates of the control group, flap center injection group and flap base injection group were 53.6 ± 6.1%, 50.6 ± 6.4% and 65.8 ± 2.4%, respectively. The flap survival areas significantly expanded in the flap base injection group (p < .05). In H-E staining beneath the skin muscle layer connective tissue thickened in the flap base injection group. In the India ink staining, abundant neovascularization was observed inside the thickened parts. Conclusion: The injection of DFAT cells into the flap base promoted the expansion of survival areas.

Comparison of Laser Doppler and Laser-Assisted Indocyanine Green Angiography Prediction of Flap Survival in a Novel Modification of the McFarlane Flap

The McFarlane rat ischemic dorsal skin flap model has been commonly used for clinical vector studies, as well as the testing of noninvasive diagnostics. However, variability of this model secondary to flap contact with the wound bed has led many to question its validity. Here we present a novel modification to the McFarlane skin flap using sterile silicone. We also use this model to test the prognostic efficacy of laser-assisted indocyanine green (ICG) angiography and laser Doppler imaging (LDI). A 3 × 9-cm dorsal skin flap with a cranially based pedicle was created, centered 1 cm distal to the scapulae. The flap was undermined, and in one of the 2 groups, a sterile silicone sheet was placed onto the wound bed. All flaps were then reapproximated with sutures 1-cm intervals. Clinical assessment and perfusion imaging was performed immediately postoperative, and at 24, 48, and 72 hours postsurgery. Postoperative day 7 clinical assessment was obtained before euthanasia. A comparative study using silicone blocked versus unblocked models (n = 6 per group) showed that, clinically, both models had equivalent flap survival [8.5 (0.913) vs 9.5 (1.01) cm]. However, a statistically significant increase in perfusion in the mid-third of unblocked models was observed on POD3 [20.28% (2.7%) vs blocked 13.45% (2.5%), P < 0.05], with a similar increase in the distal third on POD7 [18.73% (2.064%) vs 10.91% (4.19%), P < 0.05]. A prognostic study comparing LDI and ICG angiography prediction of POD7 survival at early time points (n = 10) found that LDI underpredicted flap survival at early time points [84.2% (12.03%) on POD0, 87.35% (16.11%) on POD1]. In contrast, ICG was more proficient [100.1% (10.1%) on POD0]. We present a modification of the McFarlane skin flap model that results in similar clinical results, but with a noted reduction in perfusion inconsistencies noted in unblocked models. The ICG angiography is superior to LDI in predicting POD7 flap necrosis within the first 48 hours postinjury. Future work will focus on histologic validation of our model, and vector efficacy testing.