Failure rates of artificial dermis products in treatment of diabetic foot ulcer: A systematic review and network meta-analysis

Artificial Dermis and Autologous Platelet-Rich Plasma for Treatment of Refractory Wounds: A Clinical Study

Refractory wounds present a complex and serious clinical dilemma in plastic and reconstructive surgery. However, there are currently no standard guidelines for the treatment of refractory wounds. Artificial dermis (AD) has achieved some satisfactory results, but also has some limitations. Autologous platelet-rich plasma (PRP), as a cell-therapy material, was a valuable and safe treatment dressing for chronic non-healing wounds. This study aimed to evaluate the efficacies of artificial dermis (AD) with and without autologous platelet-rich plasma (PRP) in patients with refractory wounds. Sixteen patients with refractory wounds were randomly allocated to autologous PRP therapy combined with artificial dermis (PRP + AD [N = 8]) or an artificial dermis program only (AD [N = 8]). We compared the efficacies of the two methods in terms of times to wound healing, infection control, and AD vascularization, as well as hospitalization days and eventual clinical outcomes.13 patients achieved complete healing, including seven (87.5%) in the PRP + AD group and six (75.0%) in the AD group (P > .05). The times to wound healing, infection control, and AD vascularization, and hospitalization time after transfer were significantly shorter in the PRP + AD group compared with the AD group (P < .05). In conclusion, the combination of AD and PRP promoted refractory wound healing and shortened waiting times compared with simple dermal grafts.

Use of single-layer artificial dermal template in patients with trauma and burns

Objective:

Artificial dermal templates (ADTs), were designed initially to provide extracellular matrix and skin substitute for extensive burn injuries. Use of ADTs in a variety of other indications, has also been described in the literature. In this study, we describe our experience of using ADTs for different indications in burn contractures and wound coverage.

Method:

In this retrospective study, patients requiring burn scar contracture release, permanent wound coverage for acute traumatic wounds and temporary wound coverage to prepare for complex reconstructions, and where the ADT Pelnac (Gunze Ltd., Japan) was applied, were evaluated. Data regarding patient sex, age, type and location of injury, comorbidities, operations and complications were recorded.

Results:

A total of 24 patients were included in the study, of whom 12 patients were operated on for burn contractures. ADTs were used with split-thickness skin grafts (STSGs) or Z-plasties in a single-stage procedure. In six patients, ADT and STSGs were used to cover defects with exposed bone or tendon. Of the patients, six had their wounds covered temporarily while they were stabilised for complex reconstructions or were awaiting definitive histopathological results. Revisional surgeries due to graft failures or insufficient contracture releases were required by 12 patients. All temporary wound coverage patients had successful flap reconstructions after stabilisation of their general status, had tumour-free margins in the histopathological examination, and no necrosis or infection was seen on follow-up.

Conclusion:

In this study, ADTs had positive effects on selected patients, but comprehensive and comparative clinical studies are needed for different indications to choose between these templates.

Experimental study of negative pressure wound therapy combined with platelet-rich fibrin for bone-exposed wounds

Aim: To evaluate the efficacy of negative pressure wound therapy (NPWT) combined with platelet-rich fibrin (PRF) in treating bone-exposed wounds and explore its possible mechanism. Materials & methods: A bone-exposed wound was created in a total of 32 healthy Sprague-Dawley rats, which were divided into either control group, NPWT group, PRF group or both (N + P group). The bone-exposed area, skin contraction rate and granulation coverage and the level of growth factors in granulation tissue were determined on days 4, 7 and 10. Results: The N + P group showed significantly higher wound closure rate than that achieved with others respectively. Four factors were significantly higher in N + P group than in the other three groups. Conclusion: Combination of NPWT and PRF can repair bone-exposed wounds effectively and accelerate wound healing.

Tension-Free Management of Surgical Wound in Paramalleolar Bypass

Objective: In paramalleolar bypass for critical limb-threatening ischemia (CLTI), excessive skin tension may occur for the closure of surgical wounds around the ankle. Furthermore, these surgical incisions are often proximal to infectious ischemic ulcers. Wound dehiscence caused by skin tension and surgical site infection carries a risk of graft exposure, anastomotic disruption, or graft insufficiency. Patients and Methods: Tension-free wound management was adopted in eight patients who underwent paramalleolar bypass for CLTI. Tension-free closure was adopted for surgical incisions for distal anastomotic site of the paramalleolar bypass, whereas the incisions for saphenous vein harvest were left open. A relief incision was made as needed. The opened incisions were covered with artificial dermis. Results: All surgical incisions and ischemic wounds healed successfully within 1.8 months after bypass. Two postoperative graft stenoses occurred, which were rescued by additional endovascular intervention. Secondary graft patency, wound healing, and limb salvage rates were 100% during an average follow-up period of 30 months. Conclusion: Tension-free wound closure using artificial dermis was effective in selected cases of paramalleolar bypass for CLTI.

Use of Nevelia Dermal-Epidermal Regenerative Template in the Management of Ischemic Diabetic Foot Postsurgical Wounds

The purpose of this cross-sectional study is evaluate the effectiveness of a dermal-epidermal substitute (DES) composed of 3-dimensional porous matrix of type 1, purified, stabilized, bovin-origin collagen (Nevelia, SYMATESE, Chaponost, France) without a subsequent skin graft in the treatment ischemic postsurgical diabetic foot ulcers. This study group was composed of a sample of consecutive diabetic patients with critical limb ischemia and postsurgical wounds. All patients received a preset limb salvage protocol including the application of the DES, but none received a skin graft. Patients were closely followed until wound healing or different outcome. The outcome measures were healing, nonhealing, major amputation, and death evaluated at 1 and 2 years of follow-up. Forty-one patients were included. The average postsurgical wound area was 69.6 ± 50 cm². Twenty-one patients (51%) healed; 10 patients (24%) did not heal after 1 year of follow-up; however, all of them achieved a mean ulcer size reduction >50%; 7 patients (17%) were amputees; 3 patients (7.3%) died. In a later follow-up (2 years), wounds in 8 additional patients healed. Successful revascularization was an independent predictor of healing (hazard ratio = 5.1, 95% confidence interval [CI] = 2.5-14-9; P = .0001), the postsurgical ulcer size (>50 cm²) was an independent predictor of nonhealing (hazard ratio = 6.2, 95% CI = 2.1-38.4; P = .0001) while recurrence of critical limb ischemia was an independent predictor of major amputation (odds ratio = 3.4, 95% CI = 1.1-4.5; P = .002). The DES composed of type 1 bovin-origin collagen is useful in the treatment of large postsurgical diabetic foot ulcers, even when the skin graft is not a suitable therapeutic option.

Vasculogenic Chronic Ulcer: Tissue Regeneration with an Innovative Dermal Substitute

The healing of venous and arterial ulcers is slow, and in some cases, they may not heal at all. This study aims to demonstrate the clinical advantage of Nevelia®, an innovative collagen dermal template substitute (DS) in venous and arterial chronic ulcers treatment. 35 patients affected by chronic vascular ulcers with a mean area of 35.1 ± 31.8 cm2 were treated with DS followed by autologous dermal epidermal graft (DEG). Follow-up was performed at 7-14-21 and 28 days after DS implant and 7-14-21 and 28 days after DEG. At 28 days after DEG, the mean values of Manchester Scar Scale was of 1.8 ± 0.7 for skin color, 1.6 ± 0.7 for skin contour, 1.7 ± 0.7 for distortion, and 1.7 ± 0.7 for skin texture, whereas skin was matte in 27 patients (77%) and shiny in the remaining eight cases (23%). Histological findings correlate with the clinical result showing a regenerated skin with reactive epidermal hyperplasia and dermal granulation tissue after two weeks (T1), and after three weeks (T2) a re-epithelialization and a formed new tissue architecture analogue to normal skin physiology. These data suggest that Nevelia® could be useful to treat chronic venous and arterial ulcers.

A Universal Classification System of Skin Substitutes Inspired by Factorial Design

The complexity of the dermal layer of skin means that damage to this section can result in permanent impairment of function. Partial or total dermal loss is a feature of deep burns and chronic wounds such as pressure sores or diabetic ulcers. The issues posed by traditional skin grafts have led to substantial research being carried out in the fields of tissue engineering and biomaterials science to develop a vast array of alternative skin substitutes. Given the large number of different materials, manufacturing methods, and techniques for implementation described for artificial skin substitutes, many classification systems have been created to simplify their categorization. Some of these systems are oriented toward clinicians while others toward researchers. However, none address the needs of both groups and none are intuitive. The creation of an effective classification system would be particularly helpful in the regulation, distribution, organization, and selection of skin substitutes. The aim of this review is to examine existing methods of classification of skin substitutes, and to propose a new system that uses an algorithm that is inspired by factorial design. Our system allows multiple factors to be simultaneously investigated or in this case, described, since all skin substitutes possess multiple characteristics: (1) cellularity (acellular or cellular), (2) layering (single layer or bilayer), (3) replaced region (epidermis, dermis, or both), (4) materials used (natural, synthetic, or both), and (5) permanence (temporary or permanent). The factors and levels are combined into an algorithm where all the possible combinations are shown. The multifactorial and palindromic structure of our system should enable all users to quickly understand the makeup of a selected skin substitute, or search for a skin substitute depending on their specific requirements. We feel that our proposed classification can be used by clinicians and biomedical researchers alike, which should be an advantage given the multidisciplinary nature of the tissue engineering field and the science that underpins the development of skin substitutes. We also touch upon some of the state-of-the-art skin substitutes that are commercially available or under development to demonstrate how our new method of classification might work.

Stem cells, niches and scaffolds: Applications to burns and wound care

The importance of skin to survival, and the devastating physical and psychological consequences of scarring following reparative healing of extensive or difficult to heal human wounds, cannot be disputed. We discuss the significant challenges faced by patients and healthcare providers alike in treating these wounds. New state of the art technologies have provided remarkable insights into the role of skin stem and progenitor cells and their niches in maintaining skin homeostasis and in reparative wound healing. Based on this knowledge, we examine different approaches to repair extensive burn injury and chronic wounds, including full and split thickness skin grafts, temporising matrices and scaffolds, and composite cultured skin products. Notable developments include next generation skin substitutes to replace split thickness skin autografts and next generation gene editing coupled with cell therapies to treat genodermatoses. Further refinements are predicted with the advent of bioprinting technologies, and newly defined biomaterials and autologous cell sources that can be engineered to more accurately replicate human skin architecture, function and cosmesis. These advances will undoubtedly improve quality of life for patients with extensive burns and difficult to heal wounds.