[Current German and American guidelines for autologous fat grafting - a transatlantic comparison]. / Die aktuellen Leitlinien für Autologe Fettgewebstransplantationen der Deutschen Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC) und der Fat Graft Task Force der American Society of Plastic Surgeons (ASPS) ­ ein transatlantischer Vergleich.

CLINICAL PROBLEM: The renewed clinical interest in fat grafting for both reconstructive and aesthetic purposes prompted the American Society of Plastic Surgeons to establish a Fat Graft Task Force (AFGT) in 2009. Moreover, in 2015, the German Society of Plastic, Reconstructive and Aesthetic Surgeons (DGPRÄC), in cooperation with three relevant medical societies (DDG, DGMKG, DGGG), formulated statements on the provision of strategies for patient management and to guide physicians in clinical decision making, on the basis of the scientific literature, clinical experience and current laws. The aim of this paper is to compare both guidelines in regards to recommendations on fat grafting. METHODS: Recommendations of the AFGT are based on evidence available in the published literature and graded within 5 (I-V) levels of appraisal. The available literature was reviewed by the aforementioned multidisciplinary consensus panel as well and graded according to a 4 level (I-IV) appraisal - focusing on general requirements for surgical procedures, quality of care, patient safety and legal provisions. RESULTS: For indications and practical surgical procedures, the two societies reached a unanimous consensus: Fat grafting is indicated for breast reconstruction, reconstruction of tissue deficits, and deformations caused by prior operations. Both emphasize risk groups with breast cancer (BRCA-1, BRCA-2 and family predispositions). However, in any clinical setting, results depend on the surgical procedure applied and the individual surgeon's experience. Since randomized, prospective studies are lacking and only individual case reports and clinical series or expert opinions have been published, the evidence grading does not exceed level IV to V. However, the DGPRÄC structured expert consensus panel conveys a more comprehensive and practical approach, and provides more reliable evidence to support their opinions. SUMMARY: Both societies unanimously recommend fat grafting for appropriate indications and emphasize that there are no standard guidelines for any specific procedure. The published guidelines were developed to assist physicians in choosing optimal techniques, appropriate patient selection, and offer realistic advice on outcome and potential complications. The AFGT emphasizes the need for further research and randomized controlled studies. Overall, the DGPRÄC guidelines are more detailed, practically oriented and take into consideration current German and European Tissue Laws.

Multiple Recurrences in Aggressive Forms of Dupuytren's Disease-Can Patients Benefit from Repeated Selective Fasciectomy?

BACKGROUND: In Dupuytren's disease (DD), limited fasciectomy is the mainstay of surgical therapy in patients at risk of contractures and disease recurrences. New minimally invasive treatments such as injection of collagenase clostridium histolyticum have evolved as a common tool for the preliminary treatment of Dupuytren's contractures. However, recurrences and their therapy remain controversial. In this study, we evaluate the benefit of repeated limited fasciectomy in patients with aggressive forms of the disease and multiple recurrences of contractures. METHODS: We evaluated the outcome of 16 patients undergoing limited fasciectomy 3 or more times on a single hand. RESULTS: Postoperatively, 10 of 13 (76.9%) patients were satisfied with the clinical result after the last operation; 10 of 12 (83.3%) patients would choose to have their surgery repeated, if so needed. The mean improvement of proximal interphalangeal joint range of motion was 59.2 degrees (SD 26.8) and 86.2% (SD 19.9). There were no severe complications after treatment within the observed time period. CONCLUSIONS: Our findings demonstrate that patients with recurrence of contractures after multiple previous treatments in aggressive forms of DD can benefit from surgical intervention. In conclusion, repeated limited fasciectomy remains indicated in patients after previous surgeries with DD.

Longitudinal, 3D Imaging of Collagen Remodeling in Murine Hypertrophic Scars In Vivo Using Polarization-Sensitive Optical Frequency Domain Imaging.

Hypertrophic scars (HTS), frequently seen after traumatic injuries and surgery, remain a major clinical challenge because of the limited success of existing therapies. A significant obstacle to understanding HTS etiology is the lack of tools to monitor scar remodeling longitudinally and noninvasively. We present an in vivo, label-free technique using polarization-sensitive optical frequency domain imaging for the 3D, longitudinal assessment of collagen remodeling in murine HTS. In this study, HTS was induced with a mechanical tension device for 4-10 days on incisional wounds and imaged up to 1 month after device removal; an excisional HTS model was also imaged at 6 months after injury to investigate deeper and more mature scars. We showed that local retardation and degree of polarization provide a robust signature for HTS. Compared with normal skin with heterogeneous local retardation and low degree of polarization, HTS was characterized by an initially low local retardation, which increased as collagen fibers remodeled, and a persistently high degree of polarization. This study demonstrates that polarization-sensitive optical frequency domain imaging offers a powerful tool to gain significant biological insights into HTS remodeling by enabling longitudinal assessment of collagen in vivo, which is critical to elucidating HTS etiology and developing more effective HTS therapies.

Pulsed electric fields for burn wound disinfection in a murine model.

Emerging bacterial resistance renders many antibiotics ineffective, making alternative strategies of wound disinfection important. Here the authors report on a new, physical burn wound disinfection method: pulsed electric fields (PEFs). High voltage, short PEFs create nonthermal, permanent damage to cell membranes, possibly by irreversible electroporation. In medicine, PEF technology has recently been used for nonthermal ablation of solid tumors. The authors have expanded the spectrum of PEF applications in medicine to burn wound disinfection. A third-degree burn was induced on the dorsal skin of C57BL/6 mice. Immediately after the injury, the burn wound was infected with Acinetobacter baumannii expressing the luxCDABE operon. Thirty minutes after infection, the infected areas were treated with 80 pulses delivered at 500 V/mm, 70 µs, 1 Hz. The authors used bioluminescence to quantify bacteria on skin. Three animals were used for each experimental condition. PEFs were effective in the disinfection of infected burned murine skin. The bacterial load reduction correlated with the number of delivered pulses. Forty pulses of 500 V/mm led to a 2.04 ± 0.29 Log10 reduction in bacterial load; 80 pulses led to the immediate 5.53 ± 0.30 Log10 reduction. Three hours after PEF, the bacterial reduction of the skin treated with 500 V/mm, 80 pulses was 4.91 ± 0.71 Log10. The authors introduce a new method of wound disinfection using high voltage, short PEFs. They believe that PEF technology may represent an important alternative to antibiotics in addressing bacterial contamination of wounds, particularly those contaminated with multidrug-resistant bacteria.

An automated image processing method to quantify collagen fibre organization within cutaneous scar tissue.

Standard approaches to evaluate scar formation within histological sections rely on qualitative evaluations and scoring, which limits our understanding of the remodelling process. We have recently developed an image analysis technique for the rapid quantification of fibre alignment at each pixel location. The goal of this study was to evaluate its application for quantitatively mapping scar formation in histological sections of cutaneous burns. To this end, we utilized directional statistics to define maps of fibre density and directional variance from Masson's trichrome-stained sections for quantifying changes in collagen organization during scar remodelling. Significant increases in collagen fibre density are detectable soon after burn injury in a rat model. Decreased fibre directional variance in the scar was also detectable between 3 weeks and 6 months after injury, indicating increasing fibre alignment. This automated analysis of fibre organization can provide objective surrogate endpoints for evaluating cutaneous wound repair and regeneration.

Eradication of multidrug-resistant A. baumannii in burn wounds by antiseptic pulsed electric field.

Emerging bacterial resistance to multiple drugs is an increasing problem in burn wound management. New non-pharmacologic interventions are needed for burn wound disinfection. Here we report on a novel physical method for disinfection: antiseptic pulsed electric field (PEF) applied externally to the infected burns. In a mice model, we show that PEF can reduce the load of multidrug resistant Acinetobacter baumannii present in a full thickness burn wound by more than four orders of magnitude, as detected by bioluminescence imaging. Furthermore, using a finite element numerical model, we demonstrate that PEF provides non-thermal, homogeneous, full thickness treatment for the burn wound, thus, overcoming the limitation of treatment depth for many topical antimicrobials. These modeling tools and our in vivo results will be extremely useful for further translation of the PEF technology to the clinical setting, as they provide the essential elements for planning of electrode design and treatment protocol.

Comparative analysis of processing methods in fat grafting.

BACKGROUND: Centrifugation is a popular processing method, with an unclear mechanism of action. Hypotheses include fat concentration, reduced inflammatory response by removal of blood, and concentration of adipose-derived stem cells. The authors performed multiple experiments to determine the role of centrifugation and compared it with a different processing method (mesh/gauze technique). METHODS: Lipoaspirate components were quantified after centrifugation at increasing speed to determine concentration efficacy. For comparison, the authors quantified the concentration efficacy of mesh/gauze. They also compared the number of adipose-derived stem cells isolated by either method. To determine the effects of each component, they compared fat alone to fat mixed with various spinoff components in a mouse model. They also compared centrifugation to mesh/gauze. RESULTS: The adipocyte fraction remains constant above 5000 g, whereas 1200 g results in 91 percent concentrated fat. Mesh/gauze also results in 90 percent concentrated fat. The number of adipose-derived stem cells in 1 g of fat was 1603 ± 2020 and 1857 ± 1832 in the centrifuge and mesh/gauze groups, respectively (p = 0.86). Five "add-back" groups were created: fat plus oil, fat plus surgical tumescence, fat plus fresh tumescence, fat plus cell pellets and fresh tumescence, and fat plus cell pellets. The fat-only group had better retention than the groups mixed with tumescence, regardless of whether it was surgical, fresh, or had cell pellets. Oil did not affect grafts. Centrifugation at 1200 g was equivalent to mesh/gauze (0.73 ± 0.12 g and 0.72 ± 0.13 g, respectively). CONCLUSIONS: Centrifugation improves graft retention by concentration of the adipocyte fraction. The concentration efficacy of mesh/gauze is equivalent to centrifugation at 1200 g, with equivalent in vivo outcomes.

Prevention of capsular contracture with photochemical tissue passivation.

BACKGROUND: Capsular contracture is the most common complication following the insertion of breast implants. Within a decade, half of patients will develop capsular contracture, leading to significant morbidity and need for reoperation. There is no preventative treatment available and the recurrence rate remains high. Photochemical tissue passivation is a novel tissue-stabilization technique that results in collagen cross-linking. It can rapidly link collagen fibers in situ, preserving normal tissue architecture. By using this therapy to passivate the collagenous tissues of the implant pocket, the authors hope to prevent the development of pathogenic collagen bundles and subsequent capsule contracture. METHODS: Six-cubic centimeter tissue expanders were placed below the panniculus carnosus muscle along the dorsum of New Zealand white rabbits. Fibrin glue was instilled into each implant pocket to induce contracture. Treated pockets received photochemical tissue passivation by coating them with a photosensitizing dye and exposing the area to a 532-nm light. After 8 weeks, capsule tissue was harvested for histologic evaluation. RESULTS: Implant capsule thickness is the number one prognostic factor for contracture development. The authors demonstrated a 52 percent decrease in capsule thickness in the passivated group compared with controls. Photochemical tissue passivation resulted in fewer fibrohistiocytic cells and macrophages and in reduced synovial metaplasia and smooth muscle actin deposition. CONCLUSIONS: Photochemical tissue passivation significantly decreased both capsule thickness and smooth muscle actin deposition. It is a promising technique for preventing capsular contracture that can be performed at the time of initial surgery without a significant increase in procedure time.

Micro-mechanical fractional skin rejuvenation.

BACKGROUND: The most commonly performed skin rejuvenation procedure, laser resurfacing, is associated with adverse events and significant expense. The authors have developed a novel device that uses micro-coring needles to remove tissue in a fractional pattern and avoid the side effects of laser therapy. The authors compare the efficacy of these needles to standard needles in a pig model. METHODS: One swine was treated with three needle types: standard hypodermic, solid hypodermic, and the authors' novel coring needles. Thirty-two 1 × 1-inch sites per flank received either 20 or 40 percent treatment coverage. Photographs were taken and punch biopsies were performed at days 0, 7, 28, 56, and 84. Biopsy specimens were evaluated for histology and collagen content. RESULTS: All treatment sites healed quickly, with no evidence of scarring or infection. Coring sites were easily identified and contained increased fibroblast activity and newly synthesized collagen. At 1 month, the papillary dermis and epidermis of the coring sites were up to 196 percent thicker compared with controls (p < 0.001). The coring sites had enhanced undulating rete ridges-consistent with regeneration. At 3 months, a pronounced increase in collagen fibers and newly organized and augmented elastic fibers was seen. Enzyme-linked immunosorbent assay confirmed an 89 percent increase in collagen content in these coring sites (p < 0.001). CONCLUSIONS: This novel approach to skin rejuvenation was found to effectively induce the microscopic and biological endpoints of skin rejuvenation. This may provide a new modality for the safe and cost-effective treatment of age-related rhytides, skin laxity, photodamage, scarring, and striae.

Non-thermal, pulsed electric field cell ablation: A novel tool for regenerative medicine and scarless skin regeneration.

High voltage, short pulsed electric fields (PEF) is a non-thermal ablation method, in which defined PEF irreversibly destabilize cell membranes, while preserving other tissue components such as the extracellular matrix (ECM). In the present report, we show that PEF ablated rat skin retains its microvascular blood supply and ECM structure. Complete regeneration of epidermis, hair follicles, sebaceous glands, and the panniculus carnosusis observed two months after the ablation. Our results clearly indicate that non-thermal PEF has the potential to be a powerful and novel tool for scarless tissue regeneration.