Epigastric Flap Research Articles

Effect of Simvastatin Use in Free Tissue Transfer: An Experimental Study in a Rat Epigastric Free Flap Model.

Statins are traditionally used in lowering cholesterol and low-density lipoprotein biosynthesis, but recent reports show their beneficial effect on microcirculation. The aim of this study was to investigate the effect of simvastatin on the microcirculation and in conjunction with aspirin in a rat free epigastric flap model. Thirty-six Sprague-Dawley rats were divided into group A (control, n = 12), group B (simvastatin treated, n = 12), and group C (simvastatin and aspirin, n = 12). Bilateral free epigastric skin flap was used to evaluate the effect. At 48 hours, flaps biopsies were evaluated for inflammatory activity, nitric oxide content, and thrombomodulin regulation in the endothelial lining of microvessels. Flap survival was evaluated on day 7. The diameter of microvessels and nitric oxide activity in groups B and C were significantly higher than in group A (p < 0.005 and 0.015, respectively). The perivascular inflammatory cell infiltrates and intravascular adhesions were predominant in group A compared with groups B and C (p < 0.005). Groups B and C demonstrated significant higher degree of thrombomodulin expression. The flap survival rate on day 7 was 70.8% for group A, and 87.5% and 91.7%, respectively, for groups B and C without significance between the two (p = 0.675). Simvastatin significantly improves the free flap survival by effective anti-inflammatory, vasodilator, and anticoagulant activities. Combined therapy did not have an antagonistic effect and further study is needed to see synergistic action through different mechanisms.

Does ischemic preconditioning increase flap survival by ADORA2B receptor activation?

Ischemic preconditioning (IPC) is defined as raising tolerance to subsequent ischemic stress by exposing tissues to sub-lethal ischemia. Although many candidates have been suggested, recent studies have clearly demonstrated that adenosine-mediated ADORA2B receptor (ADORA2BR) activation is the main mechanism involved in IPC. While the tissue-protective role of this mechanism has been demonstrated in different ischemia/reperfusion (I/R) models, its role in flap surgery-derived I/R damage has not to date been investigated. To investigate the role of adenosine and ADORA2BR activation in IPC-mediated tissue protection in an epigastric flap model. Animals were divided into five main groups, all of which were then divided into two subgroups depending on whether or not they were exposed to IPC before the I/R procedure, which consisted of 6 hours of ischemia and 6 days of reperfusion. No drugs were administered in Group 1 (the control group). Animals in Group 2 were pretreated with CD73-inhibitor before IPC application or the ischemic period. Animals in Group 3 were pretreated with adenosine. Animals in Group 4 were pretreated with an ADORA2BR antagonist, and those in Group 5 with an ADORA2BR agonist. After 6 days of reperfusion, tissue survival was evaluated via histological and macroscopic analysis. IPC application significantly enhanced CD73 expressions and adenosine concentrations (p < 0.01). Flap survivals were increased by IPC in Group 1 (p < 0.05). However, CD73 inhibition blocked this increase (Group 2). In Group 3, adenosine improved flap survival even in the absence of IPC (p < 0.01). While an ADORA2BR antagonist attenuated the tissue-protective effect of IPC (p < 0.01), the ADORA2BR agonist improved flap survival by mimicking IPC in groups 4 and 5. These results provide pharmacological evidence for a contribution of CD73 enzyme-dependent adenosine generation and signaling through ADORA2BR to IPC-mediated tissue protection. They also suggest for the first time that ADORA2BR agonists may be used as a potential preventive therapy against I/R injury in flap surgeries.

Ischemia and reperfusion injury in superficial inferior epigastric artery-based vascularized lymph node flaps.

Vascularized lymph node transfer (VLNT) is a promising treatment modality for lymphedema; however, how lymphatic tissue responds to ischemia has not been well defined. This study investigates the cellular changes that occur in lymph nodes in response to ischemia and reperfusion. Lymph node containing superficial epigastric artery-based groin flaps were isolated in Prox-1 EGFP rats which permits real time identification of lymphatic tissue by green fluorescence during flap dissection. Flaps were subjected to ischemia for either 1, 2, 4, or 8 hours, by temporarily occluding the vascular pedicle. Flaps were harvested after 0 hours, 24 hours, or 5 days of reperfusion. Using EGFP signal guidance, lymph nodes were isolated from the flaps and tissue morphology, cell apoptosis, and inflammatory cytokines were quantified and analyzed via histology, immunostaining, and rtPCR. There was a significant increase in collagen deposition and tissue fibrosis in lymph nodes after 4 and 8 hours of ischemia compared to 1 and 2 hours, as assessed by picrosirius red staining. Cell apoptosis significantly increased after 4 hours of ischemia in all harvest times. In tissue subject to 4 hours of ischemia, longer reperfusion periods were associated with increased rates of CD3+ and CD45+ cell apoptosis. rtPCR analysis demonstrated significantly increased expression of CXCL1/GRO-α with 2 hours of ischemia and increased PECAM-1 and TNF-α expression with 1 hour of ischemia. Significant cell death and changes in tissue morphology do not occur until after 4 hours of ischemia; however, analysis of inflammatory biomarkers suggests that ischemia reperfusion injury can occur with as little as 2 hours of ischemia.

Characterizing Nipple Biomechanics: In Search of an Ideal Tissue Substitute

INTRODUCTION: Following total mastectomy, nipple reconstruction is an essential, often last step of breast reconstruction. The positive psychological effect is critical to the recovery process, and patients report increased satisfaction, with increased happiness in sexual behavior and their nude appearance. As is the case for most reconstructive surgeries, use of autologous tissue is the ideal reconstructive methodology, eliminating the possibility of rejection, minimizing infection, and maximizing tissue integration and permanence. Autologous costal cartilage (CC) grafts have been used to maintain neo-nipple projection, but this technique is suboptimal due to difficulty of controlling the size and shape of the neo-nipple and stiff biomechanical qualities of resultant neo-nipple. We have previously shown the efficacy of minced CC in preservation of neo-nipple projection when integrated with external biodegradable scaffold. Herein, we assess simple and reliable methodologies for mechanical processing of CC to achieve desired biomechanical characteristics that mimic the human nipple more closely. METHODS: Excess CC, from patients undergoing deep inferior epigastric flap procedure, was mechanically processed by either shredding or mincing in sterile fashion. Mechanically processed cartilage was either packed into a custom-designed, 3D-printed external scaffolds (made from polylactic acid), or an equal volume was wrapped in Surgicel. The constructs were implanted into nude rats by creating a subcutaneous pocket using CV flap technique. The constructs were explanted after 3 months for histologic and biomechanical testing. Biomechanical testing was also performed on native human nipple and premanipulation/implantation CC. Confined compression testing was performed by compressing the samples to 30% of their original height in 6 steps of 5% strain, with 10 minutes between steps to allow for full stress relaxation. Equilibrium modulus was calculated. RESULTS: After 3 months in vivo, mechanical analysis demonstrated that mincing of the cartilage changed the equilibrium modulus and hydraulic permeability of implants to values closer to native human nipple regardless of presence of the external scaffold. The minced CC possessed almost 4 times smaller modulus than the premanipulation/implantation CC on average (702 versus 2,723 kPa; P = 0.0036). The average human nipple had lower, but not statistically significant, equilibrium modulus than the minced cartilage (257 versus 702 kPa). Hematoxylin/eosin staining and LIVE/DEAD assay showed the presence of healthy and viable cartilage in all groups. There was evidence of fibrovascular tissue invasion resulting in consolidation and incorporation of the implants. CONCLUSIONS: We demonstrate that autologous CC, usually discarded during a deep inferior epigastric flap procedure, can be used as a viable implant for nipple reconstruction. Because the original CC is firm and nonmalleable, mechanical processing of the CC reduces stiffness and allows for incorporation of individualized engineered constructs tailored to patient desire (sizes/levels of projection). We demonstrated that the mincing of CC resulted in constructs with more similar biomechanical properties to that of the native human nipple without the loss of projection or topography seen with traditional approaches to nipple reconstruction.

Comparison of Aesthetic Quality of the Final Scar in Abdominoplasty with Conventional and Mini Inverted t-Scar.

Background and objectives: Abdominoplasty is one of the most commonly performed cosmetic procedures. The excess skin in the conventional abdominoplasty is transversely excised and a single horizontal scar is formed. The mini inverted t-scar abdominoplasty is a modification of the “Fleur-de-lis” technique and involves the use of a small vertical incision in comparison to the long vertical incision. The aim of this technique is to lower the position of the final abdominal scar instead of addressing the horizontal laxity. In this study, we have compared the aesthetic satisfaction, width and the position of the scar with conventional abdominoplasty and mini inverted t-scar abdominoplasty. Materials and Methods: Thirty patients undergoing abdominoplasty and breast reconstruction with transverse rectus abdominis flap (TRAM) and deep inferior epigastric flap (DIEP) were included in the study. In 15 patients, abdominal closure with the conventional transverse scar was performed. In the remaining 15 patients, closure with a mini inverted t-scar was performed. Scar width, scar height and satisfaction scores were evaluated in both groups. Results: Scar widths, scar heights and patients’ and as well as surgeons’ satisfaction scores were better in the mini inverted t-scar group than the conventional group. Conclusions: The visibility of the vertical scar alone should not be a reason to avoid mini inverse t-scar abdominoplasty. Mini inverted t-scar can be an option to achieve a better hidden high-quality scar.

Hürthle Cell Carcinoma of the Thyroid - Well-Differentiated Thyroid Cancer or Something Else?

We present the case of lacrimal gland adenocarcinoma with apocrine metaplasia and a literature review for similar cases. A 65-year-old male with painless eyelid swelling was admitted to our hospital. A physical examination revealed tumor on the caudal side of the left orbital cavity, and a biopsy indicated apocrine adenocarcinoma. The patient underwent a total left orbital exenteration with eyelid resection and reconstruction using a deep inferior epigastric perforator skin flap. The pathological evaluation led to a definitive diagnosis of lacrimal gland adenocarcinoma with apocrine metaplasia. Lacrimal carcinomas are rare in the head and neck region, so there are few studies of lacrimal gland carcinoma with apocrine metaplasia. The rarity hinders extensive elucidation of the pathological characteristics and evidence-based treatment strategies.

Comparison of contraction rates of epigastric and extended dorsal island skin flaps in rats

Flap surgery is a wide field in plastic and reconstructive surgery practice and experimental research is needed to improve surgical success. These research is often performed on rats. Rat is a loose-skinned animal and contraction of skin flaps on rats is an underestimated condition. Besides this variable contraction of survived and necrotic tissues may mislead calculations and results. In this study, contraction patterns of epigastric and dorsal island skin flaps were investigated to identify this phenomenon. Forty-two male Sprague-Dawley rats were divided into four groups. Eleven epigastric flaps with unilateral pedicles, 11 epigastric flaps with bilateral pedicles, 10 extended dorsal island skin flaps with unilateral pedicles, and 10 extended dorsal island skin flaps with bilateral pedicles were prepared. Total, necrotic and viable flap areas were calculated from standardized photographs which were taken daily. The animals were placed on marked papers and image processing software was used the calculate flap areas from the photographs. Respect to these daily flap areas, the contraction rates in epigastric flaps were highly significant. The area loss in necrotic tissues were faster than the viable areas. Compared to the epigastric flaps, the contraction was not significant in extended dorsal island skin flaps flap groups. In conclusion, the rat extended dorsal island skin flap is a more reliable model for experimental flap research, which is resistant to contraction, when compared to the epigastric skin flap model.

Ischemia postconditioning protects dermal microvascular endothelial cells of rabbit epigastric skin flaps against apoptosis via adenosine A2a receptors

Background: It has been shown that endogenous adenosine-induced by ischemia postconditioning attenuates apoptosis in recent studies; however, they focus only on parenchymal cells. The detailed mechanism has not been clearly clarified in any research and the subtype of adenosine receptors involved remains unknown. In our study, dermal microvascular endothelial cells (DMECs) are used to explore the role of adenosine A2a receptor in the anti-apoptotic effects of ischemic postconditioning.Material and methods: The epigastric skin flaps of rabbits were elevated. After 4 h of ischemia, the flaps were either abruptly reperfused or postconditioned by six cycles of brief reperfusion (15s) and re-ischemia (15s). Adenosine A2a receptor agonist (CGS-21680) and antagonist (ZM-241385) were used separately in other groups. The apoptosis-related proteins and adenosine A2a receptors were determined by immunohistochemical staining. Then apoptosis index was calculated by TUNEL.Results: Ischemia/reperfusion caused severe damages in DMECs of flaps as demonstrated by an increase in apoptosis index and an increase in expressions of apoptosis-related proteins, which can be significantly attenuated by IPC treatment or exposure to a selective adenosine A2a receptor agonist (all p values <.05). Meanwhile, the anti-apoptosis effects of IPC can be blocked by a selective adenosine A2a receptor antagonist. Statistical analysis revealed that the increase of apoptosis index closely correlated inversely with the relative increase of adenosine A2a receptors (p < .0001).Conclusions: Ischemia postconditioning protects DMECs of rabbit skin flap against apoptosis via activation of adenosine A2a receptors.

Pedicle lengthening with traction vasculogenesis: Axial and perforator abdominal island flap model in rat

Background: Functional vessel elongation is possible with traction vasculogenesis technique. This study questions the effect of traction on pedicle length and flap viability of rat abdominal superficial epigastric and cephalic epigastric perforator flaps. Method: 28 Wistar-Albino rats were divided into 4 groups as superficial epigastric flap control and traction groups and cephalic epigastric perforator flap control and experiment groups. 1 mm daily traction was applied for 10 days to traction subgroups. On the 10th day pedicle length was measured and flaps were raised. 7 days after viable flap areas were measured. Statistical analysis was done. Results: In both superficial epigastric flap and cephalic epigastric perforator flap groups, pedicle length was found to be higher in traction group and flap viability was found to be higher in control groups. No relation was found between pedicle length and flap viability. Discussion: As a novel technique traction vasculogenesis may be applied to flap pedicles for elongation. This elongation process, not surprisingly may reduce the viable flap surface. However, traction vasculogenesis seems promising for functional elongation of axial and perforator flap pedicles under optimal conditions.

Combined use of ischemic preconditioning and postconditioning in a skin flap model in rats

Purpose: Reperfusion injury (RI) by abrupt restoration of circulation after prolonged ischemia remains an unsolved problem in reconstructive microsurgery. We hypothesized that the combination of ischemic preconditioning (IPreC) and ischemic postconditioning (IPostC) would result in additional preservation of epigastric skin flaps in rats after the ischemic period. Materials and Methods: We used epigastric artery skin flaps measuring 6 cm × 3 cm in 40 Wistar rats. The animals were allocated randomly into four groups: (1) Control, (2) IPreC, (3) IPostC, and (4) IPreC + IPostC group. Flap viability was assessed 1 week after the surgical procedure, and surviving flap area was recorded as a percentage of the whole flap area.Results: Animals in the IPreC, IPostC, and IPreC + IPostC groups showed significantly smaller areas of flap necrosis than those in the control group (P = 0.001). Statistical analyses indicated significant differences between the IPreC group and IPostC group (P = 0.008). However, there were no significant differences between the IPreC group and IPreC + IPostC group (P = 0.453) or between the IPostC group and the IPreC + IPostC group (P = 0.141). Conclusions: IPreC and IPostC showed protective effects against ischemia-reperfusion injury in the epigastric skin flap model. IPostC showed a greater protective effect than IPostC. The combination of preconditioning and postconditioning provided no additional benefit over either intervention performed alone in the skin flap model.

Prediction of Flap Necrosis by Using Indocyanine Green Videoangiography in Cases of Venous Occlusion in the Epigastric Flap Model of the Rat

Background A compromised free flap perfusion attributable to vascular occlusion requires immediate operative correction. Indocyanine green (ICG) videoangiography may reduce the risk of partial skin flap necrosis in high-risk free flaps in patients undergoing head and neck reconstruction. The purpose of this study was to determine the role of ICG in cases of venous congestion in a rat model. Methods A standardized epigastric flap was raised and repositioned in 35 rats. Full venous occlusion of the draining superficial inferior epigastric vein was temporarily applied for 4, 5, 6, or 7 hours. Blood flow measurements including simultaneous laser-Doppler flowmetry and tissue spectrophotometry (oxygen-to-see [O2C]) and ICG videoangiography with the FLOW 800 tool were performed before flap raising, after temporary venous stasis, and after clinical monitoring for 1 week. The Youden index computed from the receiver operating characteristic curve was used to define an optimal cutoff value for necrosis prediction after 4 and 6 hours of stasis. Results The ICG videoangiography with the FLOW 800 tool was found to be superior to O2C in the prediction of flap necrosis. The accuracy of prediction was moderate after an interval of 4 hours of stasis (area under the curve [AUC] = 0.661; 95% confidence interval [CI]: 0.489–0.834) and good after 6 hours of stasis (AUC = 0.787; 95% CI: 0.65–0.915). Conclusions The O2C does not reliably predict tissue necrosis in cases of venous congestion. ICG videoangiography is a valuable tool that can predict clinical outcome and provide guidance on whether to salvage a congested flap.

Combined caudal-superficial-epigastric axial pattern flap and full-thickness buccal mucosa graft for single-stage preputial reconstruction in six dogs.

To describe the use of a caudal superficial epigastric flap in combination with a full-thickness oral mucosal/submucosal graft for single-stage reconstruction of extensive preputial defects in dogs. Medical records of dogs with extensive preputial defects either of traumatic origin or derived from tumour excision were reviewed. In all dogs, the prepuce was reconstructed using a full-thickness oral mucosal/submucosal graft combined with a caudal superficial epigastric axial pattern flap during a single surgical procedure. Outcome was assessed by routine clinical examinations for 6months postoperatively, and through telephone follow-up thereafter. Six dogs were included. The caudal superficial epigastric axial pattern flap healed without complications in all dogs, while the full-thickness oral mucosal/submucosal graft failed in one dog. In this individual the skin flap underwent contracture 30 days after surgery and preputial advancement was required. One dog showed postoperative discomfort during urination, which was successfully managed with a Foley catheter and analgesic administration. Three dogs developed paraphimosis at 30, 80 and 90 days, respectively, and required further surgery. Long-term results were good in all dogs. The use of a full-thickness oral mucosal/submucosal graft combined with a caudal superficial epigastric axial pattern flap is feasible for single-stage preputial reconstruction in dogs. Attention should be paid to create a sufficiently large preputial opening, in order to prevent paraphimosis.

Pre‐clinical identification of potential molecular diagnostic biomarkers of secondary ischemia in microvascular fasciocutaneous flaps

Compromise of surgical microvascular flaps due to acute or late post‐operative circulatory complications remains a significant clinical problem worldwide. Timely detection of vessel occlusion may salvage a flap from necrosis, but monitoring of physical flap appearance is not always feasible and the etiology of compromise is hard to identify. Here we used a translational laboratory animal model of abdominal wall repair and Affymetrix gene expression microarray platform to reveal the molecular tissue and wound fluid markers of the arterial (AO), venous (VO) or mixed arterio‐venous (AVO) thrombosis of the pedicled flap in vivo. Bilateral 7×2.5cm epigastric flaps were raised in ~12 month old male and female Sprague‐Dawley retired breeder rats. Baseline fasciocutaneous tissue sample biopsies were obtained from the upper abdominal quadrants of sixteen sex‐matched rats prior to flap elevation. All flaps were then subjected to primary ischemia (PI), which was induced for 4 h by temporary clamping of superficial inferior epigastric artery (SIEA) and vein (SIEV) vessels to mimic free tissue transfer and anastomosis. Normoxic control (NC) samples were obtained from flaps after 24 h of non‐obstructed reperfusion. AO, VO or AVO samples were retrieved from paired flaps undergoing secondary ischemia (SI), in which SIEA, SIEV or both vessels were ligated for 4 h following 20 h of reperfusion. Total RNA was isolated from individual animal samples (n=8/gender group) and then pooled at equal concentrations prior to assessment of RNA quality. We observed 5011 (in males) and 4457 (in females) differentially expressed genes (DEGs) that demonstrated more than 2‐fold change in NC versus baseline conditions. There were 1403, 1643 and 2351 DEGs in male AO, VO and AVO flaps when compared to NC. In females, AO, VO and AVO‐associated DEG numbers were smaller (1074, 828 and 1518, respectively). Independently of gender, downregulation of keratinocyte‐specific small proline‐rich protein 4 (Sprr4) and upregulation of ankyrin repeat domain 37 (Ankrd37), previously identified as a target of hypoxia inducible factor‐1 (HIF‐1) gene, was significantly associated with the arterial SI. Venous SI was characterized by overexpression of major hematopoietic cell proteins (Gypa, Slc4a1, Lgals5, Hbq1b, Hemgn, Add2, Alas2), anti‐inflammatory bioactive lipid mediator arachidonate 15‐lipoxygenase (Alox15), CDK‐activating dual specificity phosphatase Cdc25B and Neuropeptide Y (Npy) ‐ an important neurotransmitter in skin vascular conductance. Upregulation of the latter genes distinguished VO not only from AO, but also from AVO. Finally, we identified 58 “master” DEGs shared by both genders that were present in SI regardless of its type (AO, VO, and AVO). Of these, “first‐tier” proteins included leukemia inhibitory factor (LIF), Depp1 autophagy regulator, adrenomedullin (Adm), growth arrest and DNA‐damage‐inducible, gamma (Gadd45g) and DNA‐damage‐inducible transcript 4 (Ddit4). Change in selected gene expression was further confirmed at protein or mRNA level by Western blotting or RT‐PCR analyses. In summary, our data revealed several SI‐associated diagnostic biomarkers that merit further investigation and, ultimately, validation in the human clinical trial setting.Support or Funding InformationThis work has been funded and supported by the Department of Otolaryngology ‐ Head &amp; Neck Surgery, Thomas Jefferson UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Multimodal analysis using flowmeter analysis, laser-Doppler spectrophotometry, and indocyanine green videoangiography for the detection of venous compromise in flaps in rats

Venous congestion results in tissue damage and remains the most common failure of free microvascular transfer if it is not recognized early. The purpose of this experimental study was to evaluate venous congestion and describe the findings with two different monitoring tools. A standardized epigastric flap was raised, and total occlusion of the draining vein was temporarily applied for 4, 5, 6, or 7 h. Blood flow measurements, including laser-Doppler flowmetry, and tissue spectrophotometry (O2C) and indocyanine green (ICG) videoangiography using the FLOW® 800 tool, were performed systematically after each surgical step, an interval of venous occlusion, and 1 week of clinical observation. Both monitoring tools were capable of detecting acute venous occlusion. ICG videoangiography data showed a significant decrease in the first and second maximum, and the area under the curve, during venous occlusion, whereas hemoglobin levels in the O2C analysis remained stable. Changes in fluorescence values in border areas of the flap correlated significantly with the incidence of necrosis. O2C data later showed significant correlation with the area of necrosis, and more individual changes during flap monitoring. ICG videoangiography might therefore be useful in the prediction of flap necrosis in critical areas of perfusion.

Influence of venous stasis on survival of epigastric flaps in rats

Venous congestion results in tissue damage and remains the most common reason for failure of transfer of microvascular free flaps if it is not recognised early. The purpose of this study was to measure the critical duration of venous congestion and the resultant survival of flaps according to the duration of venous stasis. A standard epigastric flap was raised and repositioned in 35 rats, seven of which acted as controls. The superficial inferior epigastric vein was fully occluded for four, five, six, or seven hours in the rest (n=7 each group). Subsequently, the rats were monitored for one week, and the resultant necrotic areas were photographed. After five, six, and seven hours of venous stasis, the incidence and area of necrosis were significantly increased (p=0.04 in each) above that of the control. The degree of necrosis after seven hours of venous stasis was significantly greater than that after four or five hours (p=0.01 and 0.02, respectively). The duration of venous congestion is therefore a potential risk for the survival of free flaps, as it results in operative complications and may jeopardise the whole procedure. After a critical period of venous stasis we reach a point of no return, and any attempt to salvage the compromised flap will be in vain. Based on these results, we think that monitoring by an experienced surgeon at intervals of no longer than three hours is essential for the successful salvage of venous congestion in microvascular free flaps.

Axial pattern skin flaps in cats: 8 cases (2000-2015)

Eight female cats of various breeds and median age of 4.5 years, with cutaneous defects in the limbs and trunk which were managed with axial pattern flaps, are described. Skin defects were caused by trauma or tumor excision. The defects were located in the medial aspect of the thigh in 2 cats, the lateral aspect of the thigh in 2, the left axilla in 2, the sternal and inguinal area in 2 and the dorsolateral abdomen and lumbar region in 1 cat. Totally 9 flaps were used including caudal superficial epigastric flap (4), thoracodorsal flap alone (1) or combined with omentalization (1), elbow fold flap and flank fold flap (2). All flaps survived and small dehiscences were found in 2 cats. All cats were healthy after a median follow up time of 13 months. The use of axial pattern flaps is a very effective method for the coverage of large skin defects in cats.

Optimization of an Arterialized Venous Fasciocutaneous Flap in the Abdomen of the Rat.

Although numerous experimental models of arterialized venous flaps (AVFs) have been proposed, no single model has gained widespread acceptance. The main aim of this work was to evaluate the survival area of AVFs produced with different vascular constructs in the abdomen of the rat. Fifty-three male rats were divided into 4 groups. In group I (n = 12), a 5-cm-long and 3-cm-wide conventional epigastric flap was raised on the left side of the abdomen. This flap was pedicled on the superficial caudal epigastric vessels caudally and on the lateral thoracic vein cranially. In groups II, III, and IV, a similar flap was raised, but the superficial epigastric artery was ligated. In these groups, AVFs were created using the following arterial venous anastomosis at the caudal end of the flap: group II (n = 13) a 1-mm-long side-to-side anastomosis was performed between the femoral artery and vein laterally to the ending of the superficial caudal epigastric vein. In group III (n = 14), in addition to the procedure described for group II, the femoral vein was ligated medially. Finally, in group IV (n = 14), the superficial caudal epigastric vein was cut from the femoral vein with a 1-mm-long ellipse of adjacent tissue, and an end-to-side arterial venous anastomosis was established between it and the femoral artery. Seven days postoperatively, the percentage of flap survival was 98.89 ± 1.69, 68.84 ± 7.36, 63.84 ± 10.38, 76.86 ± 13.67 in groups I-IV, respectively. An optimized AVF can be produced using the vascular architecture described for group IV.

Venous component in scar penetrating neovascularisation

Background: The impact of old scar tissue on the venous anatomy of a flap’s pedicle is an important question in reconstructive surgery. This study tried to investigate the venous component in scar penetrating neovascularisation.Methods: Fifty Sprague-Dawley rats were used in this experimental study. Two experimental groups were designed. In the first group, incisions were performed over the epigastric flap pedicles. In the second group, 1 cm wide segments were excised over the pedicles. Ten weeks after the initial operations, angiographies and histological examinations were performed. A control group was used to demonstrate the normal arterial and venous anatomy of the pedicle.Results: Arterial angiographies revealed that axial pattern arteries were visible in the incision group as opposed to the excision group. Although venous angiographies showed that there were more venous capillary formations in the incision group, none of the experimental groups had regenerated a vein with an axial pattern. Histological examinations revealed that venous vessel formations were significantly less in the distal samples of the experimental groups when compared to the control group (p < 0.05).Conclusions: In this study, it has been observed that arterial pedicles do regenerate over old incision scars as opposed to veins. In the excision scars neither arterial or venous restoration of the axial pedicle was possible. In these cases, only a random type of limited circulation was restored.

Treatment of Implant Exposure due to Skin Necroses after Skin Sparing Mastectomy: Initial Experiences Using a Not Selective Random Epigastric Flap.

Eight consecutive cases of implant exposure (or risk of exposure) due to skin necrosis in SSM patients over a period of 5years, all patients were treated using a random epigastric rotation flap, executed by the same medical team. A random epigastric flap (island or conventional rotation flap) was used to cover the skin defect. All the patients completed the procedure and all prostheses were saved; there were no cases of flap necrosis or infection. Cases of skin necrosis after SSM and immediate implant reconstruction, in which the implant is at risk of exposure, can be successfully treated with a random epigastric rotation flap.

Drug-Induced Atrial Fibrillation Complicates the Results of Flap Surgery in a Rat Model.

The relationship between atrial fibrillation (AF) and flap survival has not been fully characterized. Therefore, the goal of this study was to investigate the effect of AF on survival areas of pedicled flap and survival rates of free flap in an experimental rat AF model. An aconitine-induced rat AF model was established without intubation anesthesia. Survival areas of the pedicled rectangular epigastric flap were compared between AF rats (n = 7) and control rats (n = 7), and survival rates of the free epigastric flap were compared between AF rats (n = 10) and control rats (n = 10). Animals that died during the study or in which AF was not induced were excluded from study. A total of 64 rats were assessed in this study. Atrial fibrillation was induced with a success rate of 77.8% (21/27) throughout the study. Pedicled flap survival area was significantly higher in controls (75.1 ± 9.0%; n = 7) than that in AF animals (55.7 ± 13.0%; n = 7) (P < 0.01, nonpaired Student t test). Free flap survival rates were 80% in controls and 40% in AF animals (P = 0.07, χ² test). This is the first study to develop an aconitine-induced model of AF in rats. Atrial fibrillation has a detrimental effect on survival areas of the pedicled flap and survival rates of the free flap.