Limb Salvage through Intermediary Wound Coverage with Acellular Dermal Matrix Template after Persistent Pseudomonas Aeruginosa Infection in a Burn Patient

Secondary infections of skin grafts pose a continuous problem in burn patients, very often leading to loss of transplanted skin grafts and making multiple surgical revisions necessary. We present a case report about persisting Pseudomonas aeruginosa infection in burn patients with known diabetes. The burn wounds in lower extremities required repeated debridements, multiple skin grafting attempts and finally an application of the dermal scaffold NovoSorb BTM. With these measures, we managed to undertake a successful reconstruction of infected burn defects and pre-vent an amputation. We concluded that the NovoSorb BTM could be seen as an additional promising tool in a burn surgery armamentarium. In cases where radical surgical wound decontamination is not possible without risking the loss of the limb, the application of NovoSorb BTM over a contaminated field can win extra time for topical infection treatment and additionally provide an excellent skin grafting ground.

Biomechanics of skin grafts: effect of pattern size, spacing and orientation

Skin graft expansion is the key to the treatment of severe burn injuries requiring skin transplantation. While high expansions have been claimed by a majority of graft manufacturers, the realistic expansions reported to date with skin grafts are much lower. To clarify this discrepancy, we attempted to understand the biomechanics of skin grafts through the study of common graft pattern sizes, spacing, and orientation, and their influence on mesh expansion and induced stress. A novel skin simulant material and additive manufacturing were employed to develop the skin graft models. Tensile testing experiments were conducted to study expansion and overall stresses, and a finite element model (FEM) was used to characterize the local trends. At low strains (i.e., <1), the mesh expansion ratio was reported to be below 1, which increased up to 1.93 at a high strain of 2. The pattern size and spacing were not observed to affect the expansion much (i.e., <10%). With a change in orientation, the expansion decreased across all graft models and strains. High localized induced stresses were reported for high strains, which varied with graft orientation. The novel observations highlight the achievable expansions without overstressing, with standard slit patterning in skin grafts. These findings will not only help achieve better mesh expansion outcomes in burn surgeries but also guide the development of novel graft patterns for enhanced expansion in the future.

Efficacy and Safety of Viable Selective Germline Genome Edited Pigs Skin Xenotransplants in Patients with Thermal Burns

Background: Rapid closure of open wound, either temporarily or perpetually, is recognized as the standard of care in patients with thermal burns. Human cadaveric allograft and simple genetically modified porcine xenografts are not able to provide enough durable time for extensively burned patients. A selective germline genome edited pig (SGGEP) skin xenograft, Xeno X skin, would be a valuable candidate to the clinical options. Methods: In an ongoing investigator-initiated clinical trial in patients with thermal burns, the efficacy and safety of cryopreserved Xeno X skin grafts of SGGEP for burned patients were evaluated. Each patient received surgical grafting with a skin xenotransplant and wild type pig extracellular matrix (wpECM) in a side-by-side manner for in-situ comparison. The primary outcome measures of xeno-skin grafts included Xeno X skin safety and tolerability, as well as the quality and duration of temporary barrier function yielded by Xeno X skin grafts (as determined by Baux score). Seven parameters included in the analysis were vascularization, pigmentation, thickness, relief, pliability, surface area and the overall opinion, with each calculated on an independent 0-10 scale. Results: A total of 16 burned patients completed the trial. All the patients tolerated Xeno X skin grafts well and no advent events were observed. In all cases, Xeno X skin grafts were vascularized and fully adherent, they also exhibited better overall outcomes than those of wpECM. Xeno X skin grafts survived for at least 25 days without a need of any immunosuppressive drug, well consistent with our earlier preclinical studies in non- human primates. Conclusion: Xeno X skin grafts of SGGEP did not incur any signs of local and systemic safety issues, and in the meanwhile provided a high quality and long duration of temporary barrier function for burned patients. This is a major milestone in the xenotransplant field, indicating that genome-edited organ xenotransplant has become a clinical reality.

Cellular Interaction of Human Skin Cells towards Natural Bioink via 3D-Bioprinting Technologies for Chronic Wound: A Comprehensive Review

Skin substitutes can provide a temporary or permanent treatment option for chronic wounds. The selection of skin substitutes depends on several factors, including the type of wound and its severity. Full-thickness skin grafts (SGs) require a well-vascularised bed and sometimes will lead to contraction and scarring formation. Besides, donor sites for full-thickness skin grafts are very limited if the wound area is big, and it has been proven to have the lowest survival rate compared to thick- and thin-split thickness. Tissue engineering technology has introduced new advanced strategies since the last decades to fabricate the composite scaffold via the 3D-bioprinting approach as a tissue replacement strategy. Considering the current global donor shortage for autologous split-thickness skin graft (ASSG), skin 3D-bioprinting has emerged as a potential alternative to replace the ASSG treatment. The three-dimensional (3D)-bioprinting technique yields scaffold fabrication with the combination of biomaterials and cells to form bioinks. Thus, the essential key factor for success in 3D-bioprinting is selecting and developing suitable bioinks to maintain the mechanisms of cellular activity. This crucial stage is vital to mimic the native extracellular matrix (ECM) for the sustainability of cell viability before tissue regeneration. This comprehensive review outlined the application of the 3D-bioprinting technique to develop skin tissue regeneration. The cell viability of human skin cells, dermal fibroblasts (DFs), and keratinocytes (KCs) during in vitro testing has been further discussed prior to in vivo application. It is essential to ensure the printed tissue/organ constantly allows cellular activities, including cell proliferation rate and migration capacity. Therefore, 3D-bioprinting plays a vital role in developing a complex skin tissue structure for tissue replacement approach in future precision medicine.

Skin and composite grafts

Skin grafts may be used for coverage of facial defects in situations in which alternative methods of reconstruction, such as local flaps, are not an option. They may also be beneficial for patients who wish to avoid or who are not good candidates for more complex reconstruction. Full-thickness skin grafts often have a better color and texture match to adjacent skin when compared to split-thickness grafts; however, split-thickness grafts have lower metabolic demand and increased survival rate. Composite grafts may be very useful in the repair of defects with unique contour and support requirements, such as the nasal ala and eyelid. With all grafts, thoughtful planning and sound surgical technique are critical in achieving the best possible functional and aesthetic result.

Evolution of a concept with enzymatic debridement and autologous in situ cell and platelet-rich fibrin therapy (BroKerF)

Background Deep partial-thickness burns are traditionally treated by tangential excision and split thickness skin graft (STSG) coverage. STSGs create donor site morbidity and increase the wound surface in burn patients. Herein, we present a novel concept consisting of enzymatic debridement of deep partial-thickness burns followed by co-delivery of autologous keratinocyte suspension and plated-rich fibrin (PRF) or fibrin glue. Material and methods In a retrospective case study, patients with deep partial-thickness burns treated with enzymatic debridement and autologous cell therapy combined with PRF or fibrin glue (BroKerF) between 2017 and 2018 were analysed. BroKerF was applied to up to 15% total body surface area (TBSA); larger injuries were combined with surgical excision and skin grafting. Exclusion criteria were age <18 or >70 years, I°, IIa°-only, III° burns and loss of follow-up. Results A total of 20 patients with burn injuries of 16.8% ± 10.3% TBSA and mean Abbreviated Burn Severity Score 5.45 ± 1.8 were identified. Of the patients, 65% (n = 13) were treated with PRF, while 35% (n = 7) were treated with fibrin glue. The mean area treated with BroKerF was 7.5% ± 0.05% TBSA, mean time to full epithelialization was 21.06 ± 9.2 days and mean hospitalization time was 24.7 ± 14.4 days. Of the patients, 35% (n = 7) needed additional STSG, 43% (n = 3) of whom had biopsy-proven wound infections. Conclusion BroKerF is an innovative treatment strategy, which, in our opinion, will show its efficacy when higher standardization is achieved. The combination of selective debridement and autologous skin cells in a fibrin matrix combines regenerative measures for burn treatment. Lay Summary Patients suffering from large burn wounds often require the use of large skin grafts to bring burned areas to heal. Before the application of skin grafts, the burned skin must be removed either by surgery or using enzymatic agents. In this article, we describe a method where small areas of skin are taken and skin cells are extracted and sprayed on wound areas that were treated with an enzymatic agent. The cells are held in place by a substance extracted from patients’ blood (PRF) that is sprayed on the wound together with the skin cells. We believe this technique can be helpful to reduce the need of skin grafts in burned patients and improve the healing process.

Acellular fish skin grafts for the management of wounds in dogs and cats: 17 cases (2019–2021)

OBJECTIVE To report the clinical outcomes of the use of acellular fish skin grafts (FSGs) for the management of complex soft tissue wounds of various etiologies in dogs and cats. ANIMALS 13 dogs and 4 cats with complex wounds treated with FSGs between February 2019 and March 2021. PROCEDURES Medical records were reviewed for information regarding cause, location, size of the wound, management techniques, complications, and clinical outcomes. RESULTS In dogs, the number of FSG applications ranged from 1 to 4 (median, 2 graft applications). The time between each application ranged from 4 to 21 days (median, 9.5 days). Time to application of the first FSG ranged from 9 to 210 days (median, 19 days). Wounds closed by second-intention healing following the first fish skin application between 26 and 145 days (median, 71 days; n = 12). In cats, 1 or 2 FSGs were used, and the wounds of 3 of 4 cats healed completely by secondary intention. The wounds of 1 dog and 1 cat did not heal. There were no adverse events attributed to the use of the FSGs. CLINICAL RELEVANCE For dogs and cats of the present study, complete healing of most wounds occurred with the use of FSGs, the application of which did not require special training, instruments, or bandage materials.

271 Treatment of thrombophlebitic necrotic lesions in a patient with syncardia—a case report

Aims The 58 years old male patient with an important dilated cardiomyopathy, carrier of ICD, numerous malignant arrhythmias (VT) and without the possibility of a timely heart transplant, underwent emergency surgery by implanting a total artificial heart syncardia. Necrotic tissue was already present on the forearm and in the antecubital region before the surgery; it was caused by extravasation and thrombophlebitis due to continuous intravenous therapies and the lesions were deep down to tendons and bones after a surgical toilet. Years of unstable haemodynamics caused by dilated cardiomyopathy and low cardiac output led to poor peripheral vascularization giving priority to noble structures. Restoration of the tissue using advanced dressings without the use of skin grafts avoiding bacterial infections in a fragile patient. Methods and results A Pubmed search for advanced dressings was performed and a Webinar on the Wound Hygiene technique was attended. In the first instance, a polyurethane foam dressing was used and the wound on the forearm showed major improvements, subsequently with the synergistic help of the ‘Wound Hygiene’ technique and dressings based on connectivine, the tissue healed. The wound located in the antecubital region had continuous biofilm formation and a VacTherapy was planned for this. After 7 days, the conditions worsened and for this reason it was decided to use the Aqua Cell Ag +. This dressing with the silver helps in the formation of granulation tissue and it also prevents infections ‘trapping’ bacteria inside it. Conclusions The use of dressings with the Wound Hygiene technique led to the formation of new tissue without the need to perform a skin graft in a patient with a total artificial heart and without bacterial infections.