Clinical applications of basic research that shows reducing skin tension could prevent and treat abnormal scarring: the importance of fascial/subcutaneous tensile reduction sutures and flap surgery for keloid and hypertrophic scar reconstruction.
ABSTRACT We use evidence-based algorithms to treat abnormal scarring, including keloids and hypertrophic scars (HSs). This involves a multimodal approach that employs traditional methods such as surgical removal, postoperative radiotherapy, corticosteroid injection, laser, and silicone gel sheets. As a result, the rate of abnormal scarring recurrence has decreased dramatically over the past 10 years. However, several problems remain to be solved. First, despite the optimization of a radiotherapy protocol, over 10% of cases who are treated with surgery and postoperative radiotherapy still recur in our facility. Second, the treatment options for cases with huge keloids are very limited. To address these problems, we performed basic research on the mechanisms that drive the formation of keloids and HSs. Extrapolation of these research observations to the clinic has led to the development of two treatment strategies that have reduced the rate of abnormal scar recurrence further and provided a means to remove large scars. Our finite element analysis of the mechanical force distribution around keloids revealed high skin tension at the keloid edges and lower tension in the keloid center. Moreover, when a sophisticated servo-controlled device was used to stretch wounded murine dorsal skin, it was observed that the stretched samples exhibited upregulated epidermal proliferation and angiogenesis, which are also observed in keloids and HSs. Real-time RT-PCR also revealed that growth factors and neuropeptides are more strongly expressed in cyclically stretched skin than in statically stretched skin. These findings support the well-established notion that mechanical forces on the skin strongly influence the cellular behavior that leads to scarring. These observations led us to focus on the importance of reducing skin tension when keloids/HSs are surgically removed to prevent their recurrence. Clinical trials revealed that subcutaneous/fascial tensile reduction sutures, which apply minimal tension on the dermis, are more effective in reducing recurrence than the three-layered sutures used by plastic surgeons. Moreover, we have found that by using skin flaps (e.g., perforator flaps and propeller flaps), which release tension on the wound, in combination with postoperative radiotherapy, huge keloids can be successfully treated.
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ABSTRACT: It is estimated worldwide that over 6 million people per annum experience a burn injury. Despite advances in management and improved survival rates, the incidence of hypertrophic scarring remains high. These scars are particularly common after burns and are often raised, red, hard and may cause abnormal sensations. Such pathological scarring can lead to severe functional impairment, psychological morbidity, and costly long term healthcare. Wound healing is an inherent process which restores the integrity of the skin after injury and although scarring is a frequent by-product, the scarless wound healing observed in early human gestational fetuses suggests that it is not an essential component of the response. This has lead to a large body of research attempting to understand the mechanisms behind scarring and in turn prevent it. One of the main focuses of recent research has been the role played by the growth factor TGF-β in the process of both wound healing and scar formation. The three isoforms (TGF-β1, TGF-β2 and TGF-β3) appear to have overlapping functions and predominantly mediate their effects through the intracellular SMAD pathway. Initial research suggested that TGF-β1 was responsible for the fibrotic scarring response whereas the scarless wound healing seen in fetal wounds was due to increased levels of TGF-β3. However, the reality appears to be far more complex and it is unlikely that simply altering the ratio of TGF-β isoforms will lead to scarless wound healing. Other aspects of the TGF-β system that appear promising include the downstream mediator CTGF, the proteoglycan decorin and the binding protein p311. Other putative mechanisms which may underlie the pathogenesis of hypertrophic scars include excessive inflammation, excessive angiogenesis, altered levels of matrix metalloproteinases, growth factors, and delayed apoptosis of fibrotic myofibroblasts either due to p53 genetic alterations or tensile forces across the wound. If an effective treatment for hypertrophic scars following burns injury is to be developed then further work must be carried out to understand the basic mechanisms of pathological scarring.01/2012; 2(1):18-28.
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ABSTRACT: BACKGROUND: Keloids are pathological scars that arise from a fibroproliferative disorder of the skin, which causes injured skin to undergo abnormal wound healing. Recent studies suggest that keloid scarring may be a "multifactorial disorder" that is driven by various genetic factors along with local mechanophysiological skin factors. Thus, it appears that keloid scarring is a hyperplastic disorder of the skin that is determined by local factors rather than being a neoplasm like benign skin tumors, which can occur all over the body. This paper presents a review of previous papers and proposes new strategies for the prevention and treatment of keloids. METHODS: Review. RESULTS: To prevent the development of keloids, it is important to remove four primary factors that hamper proper wound healing, namely an inadequately moist environment, strong mechanical forces on the wound, foreign body reactions and allergies, and infections. If these factors are allowed to influence a wound, they can cause strong and continuous inflammation that can produce noticeable and/or growing keloids. Keloids can be treated by surgical methods, including tension-reduction sutures, z-plasties, core incision methods, and flap surgery. Adjuvant therapies of surgical or non-surgical therapies include corticosteroid injection, laser therapy (dye or Nd:YAG lasers), cryotherapy, radiotherapy, antitumor/immunosuppressive agents, stabilization/compression therapy, and make-up therapy. CONCLUSIONS: Over the last decade, many high quality studies that address keloid management and treatment have been performed. There is now sufficient evidence-based information for keloid treatment. This is likely to improve significantly as our knowledge of scar biology progresses and new agents to treat keloids are developed.European Surgery 04/2012; 44(2). DOI:10.1007/s10353-011-0065-4 · 0.26 Impact Factor
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ABSTRACT: There is a lack of information regarding the forces required for suturing human wounds. The knowledge of suturing forces serves as complementary information for setting up the limiting geometry when using tissue adhesives and it might also be used in robot-assisted surgery. The main purpose of this paper was to evaluate the forces required for suturing selected skin wounds. An elliptical wound was chosen for our study. In this study a numerical analysis and in vivo experiments were performed. Regarding the numerical models, the maximum forces occurred in the middle of the elliptical wound in all cases. In the case of highest pre-stress used in these analyses the maximal force varied from 0.5 N for the smallest wound (30 × 5 mm) to 1.5 N for the largest wound (30 × 15 mm). The maximum peak force for the wound with a size of 46 × 13 mm was 3.2 N. The minimum peak force for the wound with a size of 36 × 5 mm was 1.1 N.Medical & Biological Engineering 12/2011; 50(2):193-8. DOI:10.1007/s11517-011-0857-5 · 1.50 Impact Factor