Preclinical Assessments of a Novel Peel and Place Extended-Wear Negative-Pressure Wound Therapy Dressing for up to 35 Days in a Porcine Model.

Objective: While the use of negative pressure wound therapy (NPWT) with reticulated open cell foam (ROCF) is well established, the characteristics of ROCF do not allow for extended-wear use. There is the potential for dressing tissue ingrowth if left in place for greater than the recommended 2-3 days. An easy to use, novel peel and place dressing has been designed for extended wear with the wound management advantages of ROCF while alleviating the challenges of tissue ingrowth. Approach: Paraspinal, full-thickness or deep muscle excisional wounds were created in 11 and 2 swine, respectively, dressings applied with continuous negative pressure at -125 mmHg, and dressings changed weekly. Full-thickness excisional wounds were treated for 13 days and deep muscle wounds for 35 days. Wound dimensions were assessed. Granulation tissue thickness and re-epithelialization were measured via digital morphometry. Tissue quality, fibrinous material prevalence, and dressing removal peel force were analyzed. Results: The peel and place dressing substantially reduces dressing tissue ingrowth, is easy to remove with markedly low dressing peel force and promotes more granulation tissue at day 13 than ROCF with an interface layer. The extended-wear peel and place dressing, when applied to deep muscle wounds with weekly dressing changes, was applied for a total of 35 days. Successful wound closure was evident without any negative impact on wound healing. Innovation: This study assessed the wound management capabilities of an extended-wear peel and place NPWT dressing used until wound closure. Conclusion: The peel and place dressing is a suitable extended-wear NPWT dressing.

Preclinical assessment of novel longer-duration wear negative pressure wound therapy dressing in a porcine model.

While reticulated open cell foam (ROCF) is a well-established dressing for negative pressure wound therapy (NPWT), there is the known potential for granulation tissue ingrowth if left in place for longer than 72 h. This may cause wound bed disruption, bleeding, and pain upon dressing removal. In addition, any retained foam fragments may elicit an adverse tissue reaction. A novel, easy to use dressing designed to utilise the advantages of ROCF while addressing its challenges has recently been created. This 7 day study investigated the utility of a novel NPWT dressing under longer-duration wear circumstances while assessing the prevalence of tissue ingrowth and ease of dressing removal in full-thickness excisional wounds utilising a porcine model. Histopathology and morphometry evaluations indicated thicker granulation tissue with, depending on the parameters assessed, either comparable or better tissue quality for wounds treated with the novel dressing. Greater re-epithelialization levels were also evident compared with ROCF. Three-dimensional imaging analysis indicated faster wound fill with a corresponding decrease in wound area with the novel dressing. Furthermore, tissue ingrowth was limited to only ROCF-treated wounds, which was not unexpected in this longer-duration wear study. The force required to remove the novel dressing was considerably lower compared with ROCF, correlating to the tissue ingrowth results. Results of this study illustrate that the novel dressing provided more favourable wound healing results compared with traditional ROCF. In addition, reduction in the risk of tissue ingrowth and low dressing peel force may allow it to be used as a longer-wear dressing.

Assessment of Silver Levels in a Closed-Incision Negative Pressure Therapy Dressing: In Vitro and In Vivo Study.

Objective: In recent years, reticulated open-cell foam-based closed-incision negative pressure therapy (ROCF-ciNPT) has shown effectiveness in management of various postoperative incisions. These dressings consist of a skin interface layer that absorbs fluid from the skin surface and reduces the potential for microbial colonization within the dressing by means of ionic silver. This study examines the ability of silver to reduce the bioburden within the dressing as well as the localized effect due to potential silver mobility. Approach: Ability of silver to reduce bioburden within the ROCF-ciNPT dressing was assessed using Staphylococcus aureus, Pseudomonas aeruginosa, and Candida spp. Furthermore, silver mobility was assessed using an in vitro skin model to study the zone of inhibition along with released silver quantification. Using a porcine model, diffusion of silver into blood and tissue was studied using emission spectrometry and histology. Results: Microbial growth in the ROCF-ciNPT dressing was significantly reduced (∼2.7-4.9 log reduction) compared to a silver-free negative control. No zone of inhibition was observed for microbial colonies for up to 7 days with minimal localized silver release (<5.5 ppm release). In vivo studies demonstrated no measurable concentration (<0.2 µg/g) of silver in the blood, urine, feces, kidney, and liver tissue biopsy. Innovation: This study provides an important insight into silver concentration and mobility within the ROCF-ciNPT dressing, given emerging concerns associated with potential silver cytotoxicity. Conclusion: These results indicate the concentration of silver (0.019% silver by weight) in the ROCF-ciNPT dressings has been adequate to reduce bioburden within the skin interface layer, while severely limiting the amount of silver leaching out.