Current Status of Experimental Animal Skin Flap Models: Ischemic Preconditioning and Molecular Factors

Skin flaps are necessary in plastic and reconstructive surgery for the removal of skin cancer, wounds, and ulcers. A skin flap is a portion of skin with its own blood supply that is partially separated from its original position and moved from one place to another. The use of skin flaps is often accompanied by cell necrosis or apoptosis due to ischemia–reperfusion (I/R) injury. Proinflammatory cytokines, such as nuclear factor kappa B (NF-κB), inhibitor of kappa B (IκB), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and oxygen free radicals are known causative agents of cell necrosis and apoptosis. To prevent I/R injury, many investigators have suggested the inhibition of proinflammatory cytokines, stem-cell therapies, and drug-based therapies. Ischemic preconditioning (IPC) is a strategy used to prevent I/R injury. IPC is an experimental technique that uses short-term repetition of occlusion and reperfusion to adapt the area to the loss of blood supply. IPC can prevent I/R injury by inhibiting proinflammatory cytokine activity. Various stem cell applications have been studied to facilitate flap survival and promote angiogenesis and vascularization in animal models. The possibility of constructing tissue engineered flaps has also been investigated. Although numerous animal studies have been published, clinical data with regard to IPC in flap reconstruction have never been reported. In this study, we present various experimental skin flap methods, IPC methods, and methods utilizing molecular factors associated with IPC

Word Sense Disambiguation Using Neural Networks with Concept Co-occurrence Information

Most previous word sense disambiguation approaches based on neural networks were impractical due to their huge feature set size. We propose a method for resolving word sense ambiguity using neural networks with refined concept co-occurrence information (CCI) as features. Using CCI refinement processing, we reduce the number of features of the network to a practical size. We also show that word sense disambiguation can be improved by combining several clues rather than using them independently

Nipple-Areola Complex Necrosis after Nipple-Sparing Mastectomy with Immediate Autologous Breast Reconstruction

Background Autologous or implant-based breast reconstruction after nipple-sparing mastectomy is increasingly preferred worldwide as a breast cancer treatment option. However, postoperative nipple-areola complex (NAC) necrosis is the most significant complication of nipple-sparing mastectomy. The purpose of our study was to identify the risk factors for NAC necrosis, and to describe the use of our skin-banking technique as a solution. Methods We reviewed cases of immediate autologous breast reconstruction after nipple-sparing mastectomy at our institution between June 2005 and January 2014. The patients' data were reviewed and the risk of NAC necrosis was analyzed based on correlations between patient variables and NAC necrosis. Moreover, data pertaining to five high-risk patients who underwent the donor skin-banking procedure were included in the analysis. Results Eighty-five patients underwent immediate autologous breast reconstruction after nipple-sparing mastectomy during the study period. Partial or total NAC necrosis occurred in 36 patients (43.4%). Univariate analysis and binary regression modeling found that body mass index, smoking history, radiation therapy, and mastectomy volume were significantly associated with NAC necrosis. Of the 36 cases of NAC necrosis, 31 were resolved with dressing changes, debridement, or skin grafting. The other five high-risk patients underwent our prophylactic skin-banking technique during breast reconstruction surgery. Conclusions NAC necrosis is common in patients with multiple risk factors. The use of the skin-banking technique in immediate autologous breast reconstruction is an attractive option for high-risk patients. Banked skin can be used in such cases without requiring additional donor tissue, with good results in terms of aesthetic and reconstructive outcomes

Comparison of the Complications in Vertical Rectus Abdominis Musculocutaneous Flap with Non-Reconstructed Cases after Pelvic Exenteration

Background Perineal reconstruction following pelvic exenteration is a challenging area in plastic surgery. Its advantages include preventing complications by obliterating the pelvic dead space and minimizing the scar by using the previous abdominal incision and a vertical rectus abdominis musculocutaneous (VRAM) flap. However, only a few studies have compared the complications and the outcomes following pelvic exenteration between cases with and without a VRAM flap. In this study, we aimed to compare the complications and the outcomes following pelvic exenteration with or without VRAM flap coverage. Methods We retrospectively reviewed the cases of nine patients for whom transpelvic VRAM flaps were created following pelvic exenteration due to pelvic malignancy. The complications and outcomes in these patients were compared with those of another nine patients who did not undergo such reconstruction. Results Flap reconstruction was successful in eight cases, with minor complications such as wound infection and dehiscence. In all cases in the reconstructed group (n=9), structural integrity was maintained and major complications including bowel obstruction and infection were prevented by obliterating the pelvic dead space. In contrast, in the control group (n=9), peritonitis and bowel obstruction occurred in 1 case (11%). Conclusions Despite the possibility of flap failure and minor complications, a VRAM flap can result in adequate perineal reconstruction to prevent major complications of pelvic exenteration

Lymphatic vessel mapping in the upper extremities of a healthy Korean population

Background Intraoperative indocyanine green (ICG) lymphography can effectively detect functioning lymph vessels in edematous limbs. However, it is sometimes difficult to clearly identify their course in later-stage edematous limbs. For this reason, many surgeons rely on experience when they decide where to make the skin incision to locate the lymphatic vessels. The purpose of this study was to elucidate lymphatic vessel flow patterns in healthy upper extremities in a Korean population and to use these findings as a reference for lymphedema treatment. Methods ICG fluorescence lymphography was performed by injecting 1 mL of ICG into the second web space of the hand. After 4 hours, fluorescence images of lymphatic vessels were obtained with a near-infrared camera, and the lymphatic vessels were marked. Three landmarks were designated: the radial styloid process, the mid-portion of the cubital fossa, and the lower border of the deltopectoral groove. A straight line connecting the points was drawn, and the distance between the connected lines and the marked lymphatic vessels was measured at 8 points. Results There were 30 healthy upper extremities (15 right and 15 left). The average course of the main lymph vessels passed 26.0±11.6 mm dorsal to the styloid process, 5.7±40.7 mm medial to the mid-cubital fossa, and 31.3±26.1 mm medial to the three-quarters point of the upper landmark line. Conclusions The main functioning lymphatic vessel follows the course of the cephalic vein at the forearm level, crosses the mid-cubital point, and travels medially toward the mid-axilla

Overcome the barriers of the skin: exosome therapy

Abstract Exosomes are nano-sized cargos with a lipid bilayer structure carrying diverse biomolecules including lipids, proteins, and nucleic acids. These small vesicles are secreted by most types of cells to communicate with each other. Since exosomes circulate through bodily fluids, they can transfer information not only to local cells but also to remote cells. Therefore, exosomes are considered potential biomarkers for various treatments. Recently, studies have shown the efficacy of exosomes in skin defects such as aging, atopic dermatitis, and wounds. Also, exosomes are being studied to be used as ingredients in commercialized skin treatment products. In this review, we discussed the need for exosomes in skin therapy together with the current challenges. Moreover, the functional roles of exosomes in terms of skin treatment and regeneration are overviewed. Finally, we highlighted the major limitations and the future perspective in exosome engineering

Stabilizing Morbidity and Predicting the Aesthetic Results of Radial Forearm Free Flap Donor Sites

Background The radial forearm flap is a versatile, widely used flap. However, the possibility of donor site complications has led to concern over its use. Some surgeons prefer using other flaps whose donor sites can be closed primarily with less morbidity, including avoiding unpleasant scarring. However, in our experience, donor site stability of the radial forearm flap can be reliably achieved by using well-implemented specific procedures. Here, we present a collection of donor site cases of the radial forearm flap and investigate factors that affect the aesthetic results as the basis for a reference for selecting a radial forearm flap. Methods In this retrospective study, we reviewed 171 cases in which a radial forearm flap was used for free tissue transfer after resecting head and neck cancer. We focused on donor site morbidity rates. Each operation involved a detailed procedure designed to minimize donor site morbidity. Moreover, statistical investigations were conducted for 22 cases to determine factors affecting the scar appearance. Results Only one case developed total skin graft necrosis as a major complication. Scar-related aesthetic results were acceptable, and the body-mass index, body weight, diabetes, and cardiac problems were significant factors related to the appearance of scars. Conclusions Performing the radial forearm flap using a well-implemented detailed technique helps achieve acceptable donor site morbidity results. The aesthetic results were more promising for patients without excess body weight, diabetes, or cardiac problems. Therefore, anxiety about donor site morbidity should not be a reason to avoid selecting the radial forearm flap in suitable patients