A histological analysis of chronic wounds treated with negative pressure wound therapy to aid healing: a case series

Autologous fat grafting combined with negative pressure wound therapy in severe diabetic foot ulcer: a case study

OBJECTIVE

Hard-to-heal wounds are a surgical challenge, and diabetic foot ulcers (DFUs) are one of the most common and severe varieties. Previous studies have shown that autologous fat grafting (AFG) and negative pressure wound therapy (NPWT) have the potential to promote wound healing. This case study describes how these two methods together helped in the healing of a serious DFU.

CASE HISTORY

A 65-year-old female patient had a severe DFU on her right foot, with a 30-year history of disease and renal failure. By the time symptoms were evident, regular dressing changes and antibiotic treatment were inadequate. She received surgical debridement, AFG and NPWT. Finally, as the granulation tissue covered the full wound bed, the wound was closed by split-thickness skin grafting. One month later, the DFU was fully healed with no recurrences.

CONCLUSION

The application of AFG or components of adipose tissue to treat hard-to-heal wounds has been researched at both the molecular level and in clinic. In this case, we have proved the curative effect of jointly using AFG and NPWT.

Pre-Clinical Assessment of Single-Use Negative Pressure Wound Therapy During In Vivo Porcine Wound Healing

Objective: Traditional negative pressure wound therapy (tNPWT) systems can be large and cumbersome, limiting patient mobility and adversely affecting quality of life. PICO™, a no canister single-use system, offers a lightweight, portable alternative to tNPWT, with improved clinical performance. The aim of this study was to determine the potential mechanism(s) of action of single-use NPWT (sNPWT) versus tNPWT. Approach: sNPWT and tNPWT were applied to an in vivo porcine excisional wound model, following product use guidelines. Macroscopic, histological, and biochemical analyses were performed at defined healing time points to assess multiple aspects of the healing response. Results: Wounds treated with single-use negative pressure displayed greater wound closure and increased reepithelialization versus those treated with traditional negative pressure. The resulting granulation tissue was more advanced with fewer neutrophils, reduced inflammatory markers, more mature collagen, and no wound filler-associated foreign body reactions. Of note, single-use negative pressure therapy failed to induce wound edge epithelial hyperproliferation, while traditional negative pressure therapy compromised periwound skin, which remained inflamed with high transepidermal water loss; features not observed following single-use treatment. Innovation: Single-use negative pressure was identified to improve multiple aspects of healing versus traditional negative pressure treatment. Conclusion: This study provides important new insight into the differing mode of action of single-use versus traditional negative pressure and may go some way to explaining the improved clinical outcomes observed with single-use negative pressure therapy.

Consensus on the application of negative pressure wound therapy of diabetic foot wounds

Because China is becoming an aging society, the incidence of diabetes and diabetic foot have been increasing. Diabetic foot has become one of the main health-related killers due to its high disability and mortality rates. Negative pressure wound therapy (NPWT) is one of the most effective techniques for the treatment of diabetic foot wounds and great progress, both in terms of research and its clinical application, has been made in the last 20 years of its development. However, due to the complex pathogenesis and management of diabetic foot, irregular application of NPWT often leads to complications, such as infection, bleeding and necrosis, that seriously affect its treatment outcomes. In 2020, under the leadership of Burns, Trauma and Tissue Repair Committee of the Cross-Straits Medicine Exchange Association, the writing group for ‘Consensus on the application of negative pressure wound therapy of diabetic foot wounds’ was established with the participation of scholars from the specialized areas of burns, endocrinology, vascular surgery, orthopedics and wound repair. Drawing on evidence-based practice suggested by the latest clinical research, this consensus proposes the best clinical practice guidelines for the application and prognostic evaluation of NPWT for diabetic foot. The consensus aims to support the formation of standardized treatment schemes that clinicians can refer to when treating cases of diabetic foot.

Pilot assessment of the effect of negative pressure wound therapy on microperfusion of chronic and acute wounds

BACKGROUND

Negative pressure wound therapy (NPWT) has been established over years for treatment of chronic and complex wounds.

OBJECTIVE

Aim of this study was to investigate the effect NPWT on the microperfusion.

METHODS

Prospective single centre analysis of patients treated with NPWT due to acute (ACUTE) wounds after fasciotomy or patients with chronic wounds (CHRONIC) due to a chronic limb threatening ischemia was performed. NPWT was conducted through a three days sequence with a negative pressure of -120 mmHg. Before after and during the entire period of therapy the microperfusion was assessed (O2C™, LEA Medizintechnik).

RESULTS

Comparison of the perfusion values of 28 patients (CHRONIC/ACUTE 5/23, women/men 8/20) before and after the NPWT sequence showed a non-significant improvement in the CHRONIC group (supine position: p = 0.144, elevated position p = 0.068) and a significant decrease in the ACUTE group (supine position p = 0.012, elevated position p = 0.034). This effect could also been demonstrated during the NPWT over time (CHRONIC: supine position: p = 0.320, elevated position: p = 0.053, ACUTE: supine position: p = 0.021, elevated position: p = 0.012).

CONCLUSION

Microperfusion measurements showed alterations and differences in wound bed perfusion of acute and chronic wounds; acute wounds tended to a decrease of blood flow, whereas this effect was not seen in chronic wounds in peripheral artery disease.

Study Comparing Platform Wound Dressing, a Negative-Pressure Device without a Filler, with Three Conventional Negative-Pressure Wound Therapy Systems in the Treatment of Excisional and Incisional Wounds

BACKGROUND

All common negative-pressure wound therapy systems include a material, usually foam or gauze, at the wound/device interface. In this preclinical study, the authors have compared the effects on different wound healing parameters in the three most common negative-pressure wound therapy systems (i.e., V.A.C.VIA, PREVENA, and PICO) with a new device without foam or gauze (i.e., Platform Wound Dressing). A strong effort was made to avoid bias. The study was conducted under good laboratory practice conditions, with the presence of an independent observer.

METHODS

In pigs, three types of wounds were studied: full-thickness excisions, open incisions, and sutured closed incisions. Several macroscopic and microscopic parameters were studied. The pigs were euthanized on day 9 and all wounds were processed for histology and excisions for immunohistochemistry.

RESULTS

In general, the devices produced similar results, with only a few significant differences. In the excisions, the Platform Wound Dressing reduced wound area more than the V.A.C.VIA and the PICO. In the excisional wounds, reepithelialization was the same. In open incisions, PREVENA was better than the Platform Wound Dressing. Histologic examination showed that, in open incisions, there was less inflammation in the PREVENA-treated in comparison with the Platform Wound Dressing- and the PICO-treated wounds. Immunohistochemical analyses showed that the Platform Wound Dressing-treated excisions had significantly more blood vessels (von Willebrand factor) than the V.A.C.VIA-treated ones and that the PICO caused less T-cell activation (CD3) than the other two.

CONCLUSION

The devices-with foam, with gauze, or without either and just an embossed membrane-performed equally in general.

Negative-Pressure Wound Therapy Promotes Wound Healing by Enhancing Angiogenesis Through Suppression of NLRX1 via miR-195 Upregulation

Negative-pressure wound therapy (NPWT) is one of the most advanced therapeutic methods in the treatment of various hard-to-heal acute and refractory chronic wounds. Recent emerging evidence points to a role of the microRNA-mediated regulation of angiogenesis in ischemic tissues, and a series of microRNAs associated with angiogenesis have been successively identified. In this study, we found that miR-195 expression was significantly upregulated and the microvessel density (MVD) was increased in granulation tissue collected 7 days after NPWT compared with those in the pre-NPWT tissue. Moreover, the expression of NLRX1, the potential target gene of miR-195, was down-regulated in post-NPWT compared with that in pre-NPWT tissue. Significant negative correlations were detected between miR-195 and NLRX1 expression levels ( r = -.856, P < .001) and between NLRX1 expression and MVD ( r = -.618, P < .05), whereas miR-195 expression was positively correlated with MVD in the granulation tissue ( r = .630, P < .05). In summary, NPWT may suppress NLRX1 expression through the upregulation of miR-195 expression, thus efficaciously promoting angiogenesis in the granulation tissue to enhance wound healing.