Microdeformational Wound Therapy

Use of Vacuum-Assisted Closure to Reduce the Likelihood of Wound Complications After Limb-Sparing Resection of Pediatric Primary Bone Sarcomas of the Femur

BACKGROUND

Limb-sparing surgery is the standard of care for primary bone tumors. However, such procedures are associated with high rates of wound complications, specifically in lower-extremity surgeries. Therefore, identifying and implementing interventions to minimize the likelihood of wound complications after limb-sparing resection of the lower extremity is crucial.

METHODS

Patients who underwent limb-sparing osteosarcoma or Ewing sarcoma resection during a 7-year period at a single institution were retrospectively reviewed. Data were collected on 39 patients who underwent limb-sparing resection of the femur. Patient demographics, tumor characteristics, and perioperative and postoperative data were extracted and analyzed. Patients who underwent resection before April 2017 received conventional postoperative incision dressings. Starting in April 2017, patients received vacuum-assisted closure (VAC) with the 3 M™ Prevena VAC system after surgical closure. Eighteen patients received conventional postoperative incision dressing, and 21 received incisional wound VAC. A wound complication was defined as any Clavien-Dindo classification greater than 0 within a 28-day postoperative period.

RESULTS

Patients who received postoperative incisional wound VAC had lower rates of wound complications than those who received conventional incision dressings (14% vs. 50%; p = 0.035). Additionally, patients in whom wound complications developed had a longer average hospital stay than those without wound complications (5 days vs. 4 days; p = 0.029).

CONCLUSIONS

Wound complications prolong the hospital stay and can delay adjuvant chemotherapy for bone tumors. The use of postoperative incisional wound VAC is associated with less likelihood of wound complications and should be considered in any high-risk surgical closure.

LEVEL OF EVIDENCE

Level III Treatment Study.

The Evolution of Commercial Negative Pressure Wound Therapy Systems over the Past Three Decades

Significance: Since the introduction of the first commercial negative pressure wound therapy (NPWT) system nearly three decades ago, several key technological innovations have led to the wide adoption of the therapy. This is a review of the history and innovation of commercial NPWT systems for adjunctive management of open wounds. Recent Advances: Technical modifications have broadened NPWT options to include innovative dressing interfaces, tubing configurations, power sources, capability of topical wound solution instillation or irrigation, canister versus canister-free configurations, smart technology, and disposable versus larger reusable therapy units. While these options complicate product selection, they have greatly expanded the potential to manage a wide variety of wounds in patients who previously may not have been candidates for NPWT. Critical Issues: Basic yet mandatory requirements of NPWT include delivering an accurate level of negative pressure to the wound bed, maintaining a seal, removing wound surface exudate through the dressing interface, and patient adherence to prescribed therapy. Meeting these requirements is challenging in the face of variable wound types, wound locations, exudate levels, and exudate viscosity. While there are a growing number of marketed NPWT systems, each may have different characteristics and performance. Evaluating the functionality of each system and relevant accessories is complicated, especially as additional manufacturers enter the market. Understanding the key innovations and specific challenges they are intended to solve may aid health care providers in selecting appropriate NPWT technologies for patients. Future Directions: Evolving technology, including artificial intelligence, will likely play a major role in redefining NPWT safety, simplicity, and reliability.

Diagnosis and treatment of diabetic foot ulcer complicated with lower extremity vasculopathy: Consensus recommendation from the Chinese Medical Association (CMA), Chinese Medical Doctor Association (CMDA)

Diabetic foot ulcer complicated with lower extremity vasculopathy is highly prevalent, slow healing and have a poor prognosis. The final progression leads to amputation, or may even be life-threatening, seriously affecting patients' quality of life. The treatment of lower extremity vasculopathy is the focus of clinical practice and is vital to improving the healing process of diabetic foot ulcers. Recently, a number of clinical trials on diabetic foot ulcers with lower extremity vasculopathy have been reported. A joint group of Chinese Medical Association (CMA) and Chinese Medical Doctor Association (CMDA) expert representatives reviewed and reached a consensus on the guidelines for the clinical diagnosis and treatment of this kind of disease. These guidelines are based on evidence from the literature and cover the pathogenesis of diabetic foot ulcers complicated with lower extremity vasculopathy and the application of new treatment approaches. These guidelines have been put forward to guide practitioners on the best approaches for screening, diagnosing and treating diabetic foot ulcers with lower extremity vasculopathy, with the aim of providing optimal, evidence-based management for medical personnel working with diabetic foot wound repair and treatment.

Effectiveness of negative-pressure wound therapy to standard therapy in the prevention of complications after vascular surgery

Wound complications are common after vascular surgery and many may be preventable. Negative pressure wound therapy (NPWT) dressings may be able to reduce wound complications relating to closed incisions following vascular surgery and several devices are currently available along with a large body of literature. This review article will describe the use of NPWT dressings in vascular surgery. We will summarize the currently available systems, the likely mechanism of action of NWPT, the published studies to date and we will give our recommendations regarding the priorities for future research on this topic.

Analysis of Vacuum-Assisted Closure-Assisted Antibiotic Irrigation in Treatment of Severe Neurosurgical Central Nervous System Infections

Objective: Severe neurosurgical central nervous system infections (sNCNSIs) are among the most serious complications of neurosurgical disease. Conventional methods have shown a poor prognosis. This study aims to analyze the clinical characteristics of vacuum-assisted closure (VAC) in sNCNSIs with the help of antibiotic irrigation treatment. Patients and Methods: A retrospective study was performed for patients diagnosed with sNCNSIs. A VAC device was placed on the incision after debridement and the surgical cavity was rinsed with antibiotic agents in the VAC group. Meanwhile the surgical cavity was drained after debridement in the control group. Medical data were reviewed and analyzed. Results: Twenty-eight patients met the inclusion criteria, including 18 cases in the VAC group and 10 cases in the control group. The basic medical data showed no differences. Bacteria was isolated from 24 (85.7%) patients. The cure rate was significantly higher in the VAC group (p < 0.05). The cure rate in patients with multi-drug-resistant (MDR) infections was significantly higher in patients treated with VAC therapy (p < 0.05). The prognosis evaluated by Glasgow Outcome Score (GOS) between the two groups showed significant difference (p < 0.05). No re-infection in the VAC group occurred in the follow-up period. Conclusions: It is suggested that VAC-assisted antibiotic irrigation is safe and effective for patients with severe NCNSIs and can improve the prognosis dramatically. The results can provide a new effective and reasonable therapeutic strategy for patients with sNCNSIs.

Molecular mechanisms of action of negative pressure wound therapy: a systematic review

Negative pressure wound therapy (NPWT) has significantly advanced wound care and continues to find new applications. Its effects at a molecular level however, remain a subject of debate. The aim of this systematic review is to summarize the current evidence regarding the molecular mechanisms of action of NPWT. Medline, Embase, EBSCO databases and clinical trial registries were searched from inception to January 2023. Clinical studies, animal models or in-vitro studies that quantitatively or semi-quantitatively evaluated the influence of NPWT on growth factors, cytokine or gene-expression in the circulation or wound-bed were included. Risk of Bias assessment was performed using the RoBANS tool for non-randomized studies, the COCHRANE's Risk of Bias 2(ROB-2) tool for randomized clinical studies, OHAT tool for in-vitro studies or the SYRCLE tool for animal model studies. A descriptive summary was collated and the aggregated data is presented as a narrative synthesis. This review included 19 clinical studies, 11 animal studies and 3 in-vitro studies. The effects of NPWT on 43 biomarkers and 17 gene expressions were studied across included studies. NPWT stimulates modulation of numerous local and circulating cytokines and growth factor expressions to promote an anti-inflammatory profile. This is most likely achieved by downregulation of TNFα, upregulation of VEGF, TGF-β and fibronectin.

An Overview of Scaffolds and Biomaterials for Skin Expansion and Soft Tissue Regeneration: Insights on Zinc and Magnesium as New Potential Key Elements

The utilization of materials in medical implants, serving as substitutes for non-functional biological structures, supporting damaged tissues, or reinforcing active organs, holds significant importance in modern healthcare, positively impacting the quality of life for millions of individuals worldwide. However, certain implants may only be required temporarily to aid in the healing process of diseased or injured tissues and tissue expansion. Biodegradable metals, including zinc (Zn), magnesium (Mg), iron, and others, present a new paradigm in the realm of implant materials. Ongoing research focuses on developing optimized materials that meet medical standards, encompassing controllable corrosion rates, sustained mechanical stability, and favorable biocompatibility. Achieving these objectives involves refining alloy compositions and tailoring processing techniques to carefully control microstructures and mechanical properties. Among the materials under investigation, Mg- and Zn-based biodegradable materials and their alloys demonstrate the ability to provide necessary support during tissue regeneration while gradually degrading over time. Furthermore, as essential elements in the human body, Mg and Zn offer additional benefits, including promoting wound healing, facilitating cell growth, and participating in gene generation while interacting with various vital biological functions. This review provides an overview of the physiological function and significance for human health of Mg and Zn and their usage as implants in tissue regeneration using tissue scaffolds. The scaffold qualities, such as biodegradation, mechanical characteristics, and biocompatibility, are also discussed.

Endoscopic vacuum therapy: 2 methods of successful endosponge placement for treatment of anastomotic leak in the upper GI tract

Video 1Presentation of 2 methods of successful endosponge placement for treatment of anastomotic leak in the upper GI tract.

Negative-Pressure Wound Therapy: What We Know and What We Need to Know

Negative-pressure wound therapy (NPWT) promotes wound healing by applying negative pressure to the wound surface. A quarter of a century after its introduction, NPWT has been used in various clinical conditions, although molecular biological evidence is insufficient due to delay in basic research. Here, we have summarized the history of NPWT, its mechanism of action, what is currently known about it, and what is expected to be known in the future. Particularly, attention has shifted from the four main mechanisms of NPWT to the accompanying secondary effects, such as effects on various cells, bacteria, and surgical wounds. This chapter will help the reader to understand the current status and shortcomings of NPWT-related research, which could aid in the development of basic research and, eventually, clinical use with stronger scientific evidence.

The Association of Vacuum-Assisted Closure Therapy with Dynamic Volume Change of a Muscle Flap Transposed in an Empyema Cavity for Chronic Empyema: A Case Report

A 62-year-old woman with a history of lung resection for lung cancer was admitted to our hospital due to cough, which became progressively more severe. She was diagnosed with chronic empyema with bronchopleural fistula (BPF) of the right upper bronchial stump. Although a pedicled muscle flap was transposed to the empyema cavity, the fistula remained. We used a vacuum-assisted closure system after open-window thoracotomy and observed the cavity reduction with expansion of the transposed muscle flap. We quantitatively evaluated the dynamics of the cavity change using a three-dimensional image analysis system. A reduction of the volume of the muscle flap by prolonged empyema and expansion of the muscle flap was observed immediately after vacuum-assisted management. However, expansion of the right residual lung was not recognized. Pedicled muscle flap transposition followed by vacuum-assisted management after open-window thoracotomy may be effective for treating chronic empyema caused by BPF.

A Review: Matrix Metallopeptidase-9 Nanoparticles Targeted for the Treatment of Diabetic Foot Ulcers

Diabetes foot ulcers are a leading cause of death in diabetic individuals. There are very few medicines and treatments that have received regulatory clearance for this indication, and numerous compounds from various pharmacological classes are now in various stages of clinical studies for diabetic foot ulcers treatment. Multiple risk factors contribute to diabetic foot ulcers, including neuropathy, peripheral artery disease, infection, gender, cigarette smoking, and age. The present difficulties in diabetic foot ulcers treatment are related to bacterial resistance to currently utilized antibiotics. Inhibition of the quorum sensing (QS) system and targeting matrix metallopeptidase-9 (MMP-9) are promising. This study focuses on the difficulties of existing treatment, current treatment technique, and novel pharmacological targets for diabetic foot ulcer. The electronic data base search diabetic for literature on foot ulcers treatment was carried out using Science Direct, PubMed, Google-Scholar, Springer Link, Scopus, and Wiley up to 2021. Becaplermin, a medication that targets MMP-9, glyceryl trinitrate, which inhibits the bacterial quorum sensing system, probiotic therapy, and nano technological solutions are just a few of the novel pharmaceuticals being developed for diabetic foot ulcers treatment. A combination of therapies, rather than one particular agent, will be the best option for treatment of Diabetes foot ulcer since it is multifactorial factors that render occurs of diabetic foot ulcer.

Negative Pressure Wound Therapy: Mechanism of Action and Clinical Applications

Negative pressure wound therapy (NPWT) promotes healing by evenly applying negative pressure on the surface of the wound. The system consists of a sponge, a semiocclusive barrier, and a fluid collection system. Its effectiveness is explained by four main mechanisms of action, including macrodeformation of the tissues, drainage of extracellular inflammatory fluids, stabilization of the environment of the wound, and microdeformation. Rarely will complications linked to NPWT occur, but special care must be taken to prevent events such as toxic shock syndrome, fistulization, bleeding, and pain. New NPWT modalities have been recently developed to make NPWT suitable for a wider variety of wounds. These include NPWT with instillation therapy (NPWTi-d), different cleansing options, and application of NPWT on primarily closed incisions. Finally, vacuum-assisted wound closure therapy has been demonstrated to be efficient for various clinical settings, such as the management of diabetic foot ulcers, pressure ulcerations, chronic wounds, and skin grafts.

Filling the vacuum: Role of negative pressure wound therapy in open wound management in cats

PRACTICAL RELEVANCE

Open wounds and their treatment present a common challenge in veterinary practice. Approaching 15 years ago negative pressure wound therapy (NPWT) started to be incorporated into clinical veterinary medicine, and its availability is becoming more widespread in Europe and the USA. Use of this therapy has the potential to significantly increase the healing rate of open wounds as well as free skin grafts in small animals, and it has been occasionally described for the management of feline wounds.

AIM

This review describes the mechanisms of action of, and indications for, NPWT, and offers recommendations for NPWT specific to feline patients.

EVIDENCE BASE

The information presented is based on the current evidence and the author's clinical experience of the technique gained over the past 12 years. Comparative studies of different treatment options are lacking and, since wound healing in cats and dogs differs, cat-specific studies are especially needed. Well-designed wound healing studies comparing different advanced techniques will improve open wound healing in cats in the future, and potentially allow better understanding of the role of NPWT in this setting.

Oncoplastic breast surgery: the role of negative pressure wound therapy

Wound-related problems following breast surgery are common. Delayed wound healing can lead to poor cosmesis and, among breast cancer patients, can result in delays in receiving adjuvant treatment. The aim of our review was to look at the literature in relation to the role of negative pressure wound therapy in oncoplastic breast surgery, as at the time of writing, there is no consensus on the use of prophylactic negative pressure dressings in closed wounds following breast surgery.

Novel imaging methods reveal positive impact of topical negative pressure application on tissue perfusion in an in vivo skin model

The influence of topical negative pressure application (TNPA) on tissue perfusion still remains controversial. TNPA was applied for 30 minutes on intact skin of 21 healthy participants. Measurements of tissue oxygen saturation and tissue temperature as signs of tissue perfusion were performed before application of the TNPA, directly after removal of the TNPA and 5, 10, 15, 20, and 30 minutes after removal of the dressing using the near infrared imaging (NIRI) and a thermal imaging camera. Tissue oxygen saturation showed an increase from 67.7% before applying the TNPA to 76.1% directly after removal of TNPA, followed by a decrease of oxygen saturation 30 minutes after removal of TNPA. The measured temperature of the treated skin area increased from 32.1°C to 36.1°C after removal of TNPA with a consecutive decrease of the temperature 30 minutes after removal. TNPA resulted in both a higher tissue oxygen saturation and a higher skin temperature after 30 minutes compared to the beginning. TNPA increases both tissue oxygen saturation and skin temperature as sign of an increase of tissue perfusion. NIRI and thermal imaging proved to be useful for measuring changes in tissue perfusion.

Endoscopic vacuum therapy for anastomotic leak in esophagectomy and total gastrectomy: a systematic review and meta-analysis

The curative treatment for esophageal and gastric cancer is primarily surgical resection. One of the main complications related to esophagogastric surgery is the anastomotic leak. This complication is associated with a prolonged length of stay, reduced quality of life, high treatment costs, and an increased mortality rate. The placement of endoluminal stents is the most frequent endoscopic therapy in these cases. However, since its introduction, endoscopic vacuum therapy has been shown to be a promising alternative in the management of this complication. This study primarily aims to evaluate the efficacy and safety of endoscopic vacuum therapy for the treatment of anastomotic leak in esophagectomy and total gastrectomy. A systematic review and meta-analysis was performed. Studies that evaluated the use of endoscopic vacuum therapy for anastomotic leak in esophagectomy and total gastrectomy were included. Twenty-three articles were included. A total of 559 patients were evaluated. Endoscopic vacuum therapy showed a fistulous orifice closure rate of 81.6% (rate: 0.816; 95% CI: 0.777-0.864) and, when compared to the stent, there is a 16% difference in favor of endoscopic vacuum therapy (risk difference [RD]: 0.16; 95% CI: 0.05-0.27). The risk for mortality in the endoscopic vacuum therapy was 10% lower than in endoluminal stent therapy (RD: -0.10; 95% CI: -0.18 to -0.02). Endoscopic vacuum therapy might have a higher rate of fistulous orifice closure and a lower rate of mortality, compared to intraluminal stenting.

Which determinants are considered to be important for adherence to Negative Pressure Wound Therapy: A multimethods study

AIM

To explore the extent of patients that choose to cease Negative Pressure Wound Therapy (NPWT) prematurely in a clinical setting, and to explore the determinants of nonadherence.

METHOD

This study exists out of: (1) a retrospective study to assess the number of patients who ceased NPWT prematurely; (2) a narrative review (NR) to identify determinants of nonadherence; and (3) a survey among wound care specialists to explore specific determinants of nonadherence to NPWT.

RESULTS

(1) Based on the retrospective study, 20% ceased NPWT prematurely because of experienced limitations in daily activities. (2) Based on 22 studies, 23 determinants that might influence nonadherence were identified and added as questions in the survey. (3) Twenty-two percent (n = 136) wound care specialists completed the survey. Confidence with the healthcare team, consistency in therapy advices, coping with pain, former negative experiences with NPWT, a normal activity pattern, social support from family or friends, and support from the healthcare team were identified as highly relevant determinants of nonadherence to NPWT. Only religion scored distinctively lower.

CONCLUSION

This study is a first step in exploring the determinants of nonadherence to NPWT. In 20% NPWT was prematurely ceased at the request of the patient, this means that this therapy may have not been the best choice of therapy for this particular patient. The identification of potential determinants of nonadherence may help healthcare professionals in their dialogue with patients. The next step should be a prognostic study to assess which determinants best predict adherence to NPWT.

Clinical experience of the use of Integra in combination with negative pressure wound therapy: an alternative method for the management of wounds with exposed bone or tendon

The use of Integra has attracted great interest in the treatment of wounds with exposed bone or tendon, which may lead to associated morbidities. However, the use of Integra alone results in poor wound outcomes. We conducted a randomized clinical study to evaluate the combined effects of Integra and negative pressure wound therapy (NPWT). Thirty-six patients with wounds with exposed bone or tendons were treated with Integra alone and with a combination of Integra and NPWT (n = 18 respectively). Negative pressure (125 mm Hg) was applied intermittently till Integra was revascularized. The take rate of Integra and time taken from Integra coverage to skin transplantation was recorded for each case. The average take rate of Integra in the conventional treatment group (Integra with partial packing compression dressings) was lower than that for the new treatment group (Integra with NPWT) (p < 0.001, 95% CI: 6.44-0.20). The mean time period from Integra coverage to skin transplantation was longer for the conventional treatment group than for the new treatment group (p < 0.001, 95% CI: -13.18 to -11.24). The application of NPWT could potentially increase the take rate of Integra and shorten the duration of hospital stay. The use of Integra with NPWT could be a treatment option for wounds with exposed bone or tendon.

The modulation of the burn wound environment by negative pressure wound therapy: Insights from the proteome

Negative pressure wound therapy has been used to promote wound healing in a variety of settings, including as an adjunct to silver-impregnated dressings in the acute management of paediatric burns. Fluid aspirated by the negative pressure wound therapy system represents a potentially insightful research matrix for understanding the burn wound microenvironment and the intervention's biochemical mechanisms of action. The aim of this study was to characterize the proteome of wound fluid collected using negative pressure wound therapy from children with small-area thermal burns. Samples were obtained as part of a randomized controlled trial investigating the clinical efficacy of adjunctive negative pressure wound therapy. They were compared with blister fluid specimens from paediatric burn patients matched according to demographic and injury characteristics. Protein identification and quantification were performed via liquid chromatography tandem mass spectrometry and sequential window acquisition of all theoretical mass spectra data-independent acquisition. Proteins and biological pathways that were unique to or enriched in negative pressure wound therapy fluid samples were evaluated using principal components, partial least squares-discriminant, and gene ontology enrichment analyses. Eight viable samples of negative pressure wound therapy fluid were collected and analyzed with eight matched blister fluid samples. A total of 502 proteins were quantitatively profiled in the negative pressure wound therapy fluid, of which 444 (88.4%) were shared with blister fluid. Several proteins exhibited significant abundance differences between fluid types, with negative pressure wound therapy fluid showing a higher abundance of matrix metalloproteinase-9, arginase-1, low affinity immunoglobulin gamma Fc region receptor III-A, filamin-A, alpha-2-macroglobulin, and hemoglobin subunit alpha. The results lend support to the hypothesis that negative pressure wound therapy augments wound healing through the modulation of factors involved in the inflammatory response, granulation tissue synthesis, and extracellular matrix maintenance. Data are available via ProteomeXchange with identifier PXD023168.

Role of Endoscopic Vacuum Therapy as a Treatment for Anastomosis Leak after Esophageal Cancer Surgery

Esophageal anastomotic leak is the most common and serious complication following esophagectomy. However, the standard treatment for anastomotic leaks remains unclear. Recently, endoscopic vacuum therapy has become an important non-surgical alternative treatment method for patients with esophageal anastomotic leak. This treatment involves the endoscopic placement of a sponge connected to a nasogastric tube into the defect cavity or lumen. Subsequently, continuous negative pressure is delivered to the cavity through the tube. Several studies have reported a treatment success rate of 80% to 100%. In this study, we review the mechanism of action, the method of performing the procedure, its safety and efficacy, and prognostic factors for failure of endoscopic vacuum therapy in the management of patients with anastomotic leak, and on this basis attempted to confirm the possibility of establishing a standardized treatment protocol using endoscopic vacuum therapy.

Reducing the Risk of Postoperative Problems With Panniculectomies Using the Prevena Plus™ 125 Incisional Management Dressing

Abdominal wall reconstruction procedures have become increasingly popular in recent years as technology and surgical techniques have improved. The downside to these procedures has been the high rate of postoperative complications. Surgical site infections have been reported as high as 33.7% of the $9.8 billion spent annually on these complications. I present the case of a 62-year-old morbidly obese woman who underwent a combined procedure of abdominal wall reconstruction and panniculectomy. A total of 45 lbs of pannus was removed through a transverse incision that extended from hip to hip, measuring 90 cm in length. Following panniculectomy, abdominal wall reconstruction was performed by mobilizing the abdominal skin flap from the lower abdominal panniculectomy incision (avoiding a T-shaped incision with a traditionally high risk of dehiscence), and placement of biologic mesh as an underlay followed by fascial closure. Prevena Plus™ 125 (3M + KCI, San Antonio, TX) was applied for postoperative closed incisional negative pressure therapy (ciNPT) and continued for 10 days. No postoperative complications occurred. The incision healed without incident with no hernia recurrence at one year. ciNPT in high-risk patients can help minimize the risk of postoperative wound healing complications and should be considered in high-risk patients. Those patients undergoing combined procedures and especially morbidly obese patients undergoing combined abdominal wall reconstruction and panniculectomy are at particularly high risk for wound healing complications. ciNPT should be considered as a postoperative dressing of choice in this challenging patient population.

Negative pressure wound therapy for patients with hard-to-heal wounds: a systematic review

OBJECTIVE

Despite the lack of evidence, negative pressure wound therapy (NPWT) is commonly used in patients with hard-to-heal wounds. In our medical centre, one third of patients with abdominal wounds infected postoperatively end this therapy prematurely due to negative experiences and prefer standard wound care. This study was designed to explore the effects of NPWT on quality of life (QoL).

METHOD

A search from 2000 to 2019 in eight databases was performed to identify qualitative studies of patients treated with NPWT. Studies were selected by two independent reviewers, who appraised the methodological quality, extracted and structured the data and performed content analysis.

RESULTS

A total of five qualitative studies with good methodological quality, incorporating 51 individual patients, were included. After content analysis, four major themes emerged: reduced freedom of movement caused by an electric device; decreased self-esteem; increased social and professional dependency; and gaining self-control.

CONCLUSION

NPWT has major effects on the physical, psychological and social domains of QoL. Knowledge of these effects may lead to improved treatment decisions for patients with hard-to-heal wounds regarding use of NPWT or standard wound care.

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

OBJECTIVE

Our aim was to examine histopathological changes in three chronic wounds, and to assess whether the application of negative pressure wound therapy (NPWT) changes the wound bed environment.

METHOD

- Results: We recruited three patients were recruited who had a non-healing wounds in excess of eight weeks. Histopathological changes in the wound bed supported the evidence that NPWT changes the wound bed environment by reducing inflammatory damage and facilitating wound bed perfusion with angiogenesis.

CONCLUSION

We suggest that NPWT is a valuable adjunct to aid chronic wound healing. In this case series, we observed histopathological changes and improvement in the wounds, following one week's treatment with NPWT. Further analysis should be done to demonstrate any interaction between the cells involved in the wound healing process is enhanced, growth factor performance is optimised and cell migration is achieved following NPWT, in order to facilitate the healing process.

EWMA Document: Negative Pressure Wound Therapy

1. Introduction Since its introduction in clinical practice in the early 1990's negative pressure wounds therapy (NPWT) has become widely used in the management of complex wounds in both inpatient and outpatient care.¹ NPWT has been described as a effective treatment for wounds of many different aetiologies^2,3 and suggested as a gold standard for treatment of wounds such as open abdominal wounds,^4-6 dehisced sternal wounds following cardiac surgery^7,8 and as a valuable agent in complex non-healing wounds.^9,10 Increasingly, NPWT is being applied in the primary and home-care setting, where it is described as having the potential to improve the efficacy of wound management and help reduce the reliance on hospital-based care.¹¹ While the potential of NPWT is promising and the clinical use of the treatment is widespread, highlevel evidence of its effectiveness and economic benefits remain sparse.^12-14 The ongoing controversy regarding high-level evidence in wound care in general is well known. There is a consensus that clinical practice should be evidence-based, which can be difficult to achieve due to confusion about the value of the various approaches to wound management; however, we have to rely on the best available evidence. The need to review wound strategies and treatments in order to reduce the burden of care in an efficient way is urgent. If patients at risk of delayed wound healing are identified earlier and aggressive interventions are taken before the wound deteriorates and complications occur, both patient morbidity and health-care costs can be significantly reduced. There is further a fundamental confusion over the best way to evaluate the effectiveness of interventions in this complex patient population. This is illustrated by reviews of the value of various treatment strategies for non-healing wounds, which have highlighted methodological inconsistencies in primary research. This situation is confounded by differences in the advice given by regulatory and reimbursement bodies in various countries regarding both study design and the ways in which results are interpreted. In response to this confusion, the European Wound Management Association (EWMA) has been publishing a number of interdisciplinary documents^15-19 with the intention of highlighting: The nature and extent of the problem for wound management: from the clinical perspective as well as that of care givers and the patients Evidence-based practice as an integration of clinical expertise with the best available clinical evidence from systematic research The nature and extent of the problem for wound management: from the policy maker and healthcare system perspectives The controversy regarding the value of various approaches to wound management and care is illustrated by the case of NPWT, synonymous with topical negative pressure or vacuum therapy and cited as branded VAC (vacuum-assisted closure) therapy. This is a mode of therapy used to encourage wound healing. It is used as a primary treatment of chronic wounds, in complex acute wounds and as an adjunct for temporary closure and wound bed preparation preceding surgical procedures such as skin grafts and flap surgery. Aim An increasing number of papers on the effect of NPWT are being published. However, due to the low evidence level the treatment remains controversial from the policy maker and health-care system's points of view-particularly with regard to evidence-based medicine. In response EWMA has established an interdisciplinary working group to describe the present knowledge with regard to NPWT and provide overview of its implications for organisation of care, documentation, communication, patient safety, and health economic aspects. These goals will be achieved by the following: Present the rational and scientific support for each delivered statement Uncover controversies and issues related to the use of NPWT in wound management Implications of implementing NPWT as a treatment strategy in the health-care system Provide information and offer perspectives of NPWT from the viewpoints of health-care staff, policy makers, politicians, industry, patients and hospital administrators who are indirectly or directly involved in wound management.

MicroRNA-615-5p Regulates Angiogenesis and Tissue Repair by Targeting AKT/eNOS (Protein Kinase B/Endothelial Nitric Oxide Synthase) Signaling in Endothelial Cells

Objective- In response to tissue injury, the appropriate progression of events in angiogenesis is controlled by a careful balance between pro and antiangiogenic factors. We aimed to identify and characterize microRNAs that regulate angiogenesis in response to tissue injury. Approach and Results- We show that in response to tissue injury, microRNA-615-5p (miR-615-5p) is rapidly induced and serves as an antiangiogenic microRNA by targeting endothelial cell VEGF (vascular endothelial growth factor)-AKT (protein kinase B)/eNOS (endothelial nitric oxide synthase) signaling in vitro and in vivo. MiR-615-5p expression is increased in wounds of diabetic db/db mice, in plasma of human subjects with acute coronary syndromes, and in plasma and skin of human subjects with diabetes mellitus. Ectopic expression of miR-615-5p markedly inhibited endothelial cell proliferation, migration, network tube formation in Matrigel, and the release of nitric oxide, whereas miR-615-5p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3' untranslated region reporter and microribonucleoprotein immunoprecipitation assays, and small interfering RNA dependency studies demonstrate that miR-615-5p inhibits the VEGF-AKT/eNOS signaling pathway in endothelial cells by targeting IGF2 (insulin-like growth factor 2) and RASSF2 (Ras-associating domain family member 2). Local delivery of miR-615-5p inhibitors, markedly increased angiogenesis, granulation tissue thickness, and wound closure rates in db/db mice, whereas miR-615-5p mimics impaired these effects. Systemic miR-615-5p neutralization improved skeletal muscle perfusion and angiogenesis after hindlimb ischemia in db/db mice. Finally, modulation of miR-615-5p expression dynamically regulated VEGF-induced AKT signaling and angiogenesis in human skin organoids as a model of tissue injury. Conclusions- These findings establish miR-615-5p as an inhibitor of VEGF-AKT/eNOS-mediated endothelial cell angiogenic responses and that manipulating miR-615-5p expression could provide a new target for angiogenic therapy in response to tissue injury. Visual Overview- An online visual overview is available for this article.

Microdeformational wound therapy: A novel option to salvage complex wounds associated with the Nuss procedure

BACKGROUND

Complex wounds associated with the Nuss procedure are a resource intensive complication that may lead to significant morbidity with potential removal of the implanted device and abandonment of the repair. We report our management technique of this complication utilizing microdeformational wound therapy (MDWT) that is safe, is efficacious and allows for salvage of the repair.

OPERATIVE TECHNIQUE

We defined a complex wound as a wound that became suppurative and drained in the postoperative period and failed to resolve with a trial of conventional wound management and antibiotics. Upon recognition of a complex wound, we recommend an initial operative wound debridement. This allows wound cultures, wound assessment and precise initiation of MDWT. It is not uncommon to have exposed hardware in the wound early in the course of therapy. Metal allergy must be excluded. The patient is transitioned to oral antibiotics following resolution of the acute process. MDWT is performed until the wounds are completely epithelialized with no clinical signs of drainage or infection. The average length of MDWT in our patients was 39 days. Following complete wound healing the patients are maintained on antibiotics until implant removal.

CONCLUSIONS

The use of microdeformational wound therapy in complex wounds associated with the Nuss procedure is a safe and effective modality. The technique may reduce the likelihood of implant removal with potential recurrent pectus excavatum.

TYPE OF STUDY

Operative technique.

LEVEL OF EVIDENCE

Level IV, case series with no comparison group.

pH-responsive calcium alginate hydrogel laden with protamine nanoparticles and hyaluronan oligosaccharide promotes diabetic wound healing by enhancing angiogenesis and antibacterial activity

Diabetic wounds as chronic wounds represent a severe, persistent complication of diabetes and, in the most extreme cases, can lead to amputation. Two critical and unfavorable factors affecting diabetic wound healing are sustained bacterial-induced chronic inflammation and disrupted vascularization. In this paper, we presented a novel, pH-responsive calcium alginate hydrogel laden with protamine nanoparticles and hyaluronan oligosaccharides, and explored its potential for accelerating diabetic wound healing. A thorough investigation indicated that the drug- and nanoparticle-loaded hydrogel demonstrated strong bactericidal behavior mediated by protamine nanoparticles and reduced bacterial-induced chronic inflammation at the wound site. Furthermore, it accelerated the wound-healing process by promoting angiogenesis in skin wounds with the hyaluronan oligosaccharide-mediated enhanced expression of vascular endothelial growth factor.

Targeting MMP-9 in Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are significant complications of diabetes and an unmet medical need. Matrix metalloproteinases (MMPs) play important roles in the pathology of wounds and in the wound healing process. However, because of the challenge in distinguishing active MMPs from the two catalytically inactive forms of MMPs and the clinical failure of broad-spectrum MMP inhibitors in cancer, MMPs have not been a target for treatment of DFUs until recently. This review covers the discovery of active MMP-9 as the biochemical culprit in the recalcitrance of diabetic wounds to healing and targeting this proteinase as a novel approach for the treatment of DFUs. Active MMP-8 and MMP-9 were observed in mouse and human diabetic wounds using a batimastat affinity resin and proteomics. MMP-9 was shown to play a detrimental role in diabetic wound healing, whereas MMP-8 was beneficial. A new class of selective MMP-9 inhibitors shows clinical promise for the treatment of DFUs.

Role of endoscopic vacuum therapy in the management of gastrointestinal transmural defects

A gastrointestinal (GI) transmural defect is defined as total rupture of the GI wall, and these defects can be divided into three categories: perforations, leaks, and fistulas. Surgical management of these defects is usually challenging and may be associated with high morbidity and mortality rates. Recently, several novel endoscopic techniques have been developed, and endoscopy has become a first-line approach for therapy of these conditions. The use of endoscopic vacuum therapy (EVT) is increasing with favorable results. This technique involves endoscopic placement of a sponge connected to a nasogastric tube into the defect cavity or lumen. This promotes healing via five mechanisms, including macrodeformation, microdeformation, changes in perfusion, exudate control, and bacterial clearance, which is similar to the mechanisms in which skin wounds are treated with commonly employed wound vacuums. EVT can be used in the upper GI tract, small bowel, biliopancreatic regions, and lower GI tract, with variable success rates and a satisfactory safety profile. In this article, we review and discuss the mechanism of action, materials, techniques, efficacy, and safety of EVT in the management of patients with GI transmural defects.

MicroRNA-135a-3p regulates angiogenesis and tissue repair by targeting p38 signaling in endothelial cells

Angiogenesis is a critical process in repair of tissue injury that is regulated by a delicate balance between pro- and antiangiogenic factors. In disease states associated with impaired angiogenesis, we identified that miR-135a-3p is rapidly induced and serves as an antiangiogenic microRNA (miRNA) by targeting endothelial cell (EC) p38 signaling in vitro and in vivo. MiR-135a-3p overexpression significantly inhibited EC proliferation, migration, and network tube formation in matrigel, whereas miR-135-3p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3'-UTR reporter and miRNA ribonucleoprotein complex -immunoprecipitation assays, and small interfering RNA dependency studies revealed that miR-135a-3p inhibits the p38 signaling pathway in ECs by targeting huntingtin-interacting protein 1 (HIP1). Local delivery of miR-135a-3p inhibitors to wounds of diabetic db/db mice markedly increased angiogenesis, granulation tissue thickness, and wound closure rates, whereas local delivery of miR-135a-3p mimics impaired these effects. Finally, through gain- and loss-of-function studies in human skin organoids as a model of tissue injury, we demonstrated that miR-135a-3p potently modulated p38 signaling and angiogenesis in response to VEGF stimulation by targeting HIP1. These findings establish miR-135a-3p as a pivotal regulator of pathophysiological angiogenesis and tissue repair by targeting a VEGF-HIP1-p38K signaling axis, providing new targets for angiogenic therapy to promote tissue repair.-Icli, B., Wu, W., Ozdemir, D., Li, H., Haemmig, S., Liu, X., Giatsidis, G., Cheng, H. S., Avci, S. N., Kurt, M., Lee, N., Guimaraes, R. B., Manica, A., Marchini, J. F., Rynning, S. E., Risnes, I., Hollan, I., Croce, K., Orgill, D. P., Feinberg, M. W. MicroRNA-135a-3p regulates angiogenesis and tissue repair by targeting p38 signaling in endothelial cells.

Does Vacuum-assisted Closure Reduce the Risk of Wound Complications in Patients With Lower Extremity Sarcomas Treated With Preoperative Radiation?

BACKGROUND

Although preoperative radiation followed by wide local excision yields excellent local control in soft tissue sarcomas, the risk of wound complications is reported to be higher compared with the incidence in patients who were administered postoperative radiation therapy. Vacuum (vac)-assisted closure may improve wound healing, but it is unknown whether vac-assisted closure during soft tissue sarcoma resection may reduce the risk of wound complications or impair local disease control.

QUESTIONS/PURPOSES

(1) Does the use of a wound vac application at the time of soft tissue sarcoma resection reduce the risk of developing wound complications after lower extremity sarcoma resection? (2) Is vac-assisted closure associated with an increased risk of local relapse?

METHODS

From 2000 to 2016, 312 patients with stage I to III soft tissue sarcomas were treated. Of these, 123 were treated with preoperative radiation ± chemotherapy followed by limb-sparing resection based on tumor location, size, grade, histology, and patient age. There was a minimum followup of 12 months. Radiation was delivered generally based on tumor size, grade, superficial versus deep nature, and proximity to neurovascular structures. Chemotherapy was administered in patients < 70 years old with high-grade tumors and tumors > 5 cm. Patient, demographic, and treatment variables, including incisional vac application and wound outcomes, were retrospectively evaluated. Incisional vac-assisted closure took place at the time of primary resection in 32% (46 of 123) of patients. Vac-assisted closure was considered when there was a concern for risk of external contamination such as instances in which fixation of adhesives would be difficult or regions where there was a high risk of contamination. Vac-assisted closure may have also been used in instances with increased wound tension at closure or with heightened concern for shearing on the wound such as buttock wounds. Ten patients were lost to followup, two in the vac group and eight in the non-vac group. Potential factors associated with wound complications were evaluated using Fisher's exact test for univariate analysis and logistic regression for multivariate analysis. Local recurrence-free survival was evaluated using the Kaplan-Meier estimate.

RESULTS

After taking into consideration factors such as tumor size, location, age, and patient comorbidities, it was shown that patients who underwent vac-assisted closure were less likely to experience wound complications compared with patients who did not undergo vac-assisted closure (odds ratio, 0.129; 95% confidence interval [CI], 0.041-0.398; p = 0.004). The local control incidence in the entire cohort was 98%. With the numbers available, Kaplan-Meier survivorship free from local recurrence did not differ between patients treated with or without the vac (100% [95% CI, 154.09-154.09] versus 96% [95% CI, 152.21-169.16]; p = 0.211), respectively.

CONCLUSIONS

Vac-assisted closure at the time of resection of proximal lower extremity soft tissue sarcomas is associated with a lower risk of wound complications, and its use apparently did not compromise local control. We show that the use of vac-assisted closure may be worth considering in surgeons' attempts to reduce the risk of wound complications among patients with soft tissue sarcomas of the proximal lower extremities.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Negative pressure wound therapy use in diabetic foot syndrome-from mechanisms of action to clinical practice

BACKGROUND

Diabetes and its complications constitute a rising medical challenge. Special attention should be given to diabetic foot syndrome (DFS) due to its high rate of associated amputation and mortality. Negative pressure wound therapy (NPWT) is a frequently used supportive modality in a diabetic foot with ulcerations (DFUs).

DESIGN

Here, we reviewed the current knowledge concerning the tissue and molecular mechanisms of NPWT action with an emphasis on diabetes research followed by a summary of clinical DFU studies and practice guidelines.

RESULTS

Negative pressure wound therapy action results in two types of tissue deformations-macrodeformation, such as wound contraction, and microdeformation occurring at microscopic level. Both of them stimulate a wound healing cascade including tissue granulation promotion, vessel proliferation, neoangiogenesis, epithelialization and excess extracellular fluid removal. On the molecular level, NPWT results in an alteration towards more pro-angiogenic and anti-inflammatory conditions. It increases expression of several key growth factors, including vascular endothelial growth factor and fibroblast growth factor 2, while expression of inflammatory cytokinesis reduced. The NPWT application also alters the presence and function of matrix metalloproteinases. Clinical studies in DFU patients showed a superiority of NPWT over standard therapy in terms of efficacy outcomes, primarily wound healing and amputation rate, without a rise in adverse events. International guidelines point to NPWT as an important adjuvant therapy in DFU whose use is expected to increase.

CONCLUSIONS

This current knowledge improves our understanding of NPWT action and its tailoring for application in diabetic patients. It may inform the development of new treatments for DFU.

Study of negative pressure wound therapy as an adjunct treatment for acute burns in children (SONATA in C): protocol for a randomised controlled trial

BACKGROUND

Although negative pressure wound therapy (NPWT) is widely used in the management of several wound types, its efficacy as a primary therapy for acute burns has not yet been adequately investigated, with research in the paediatric population particularly lacking. There is limited evidence, however, that NPWT might benefit children with burns, amongst whom scar formation, wound progression and pain continue to present major management challenges. The purpose of this trial is to determine whether NPWT in conjunction with standard therapy accelerates healing, reduces wound progression and decreases pain more effectively than standard treatment alone.

METHODS/DESIGN

A total of 104 children will be recruited for this trial. To be eligible, candidates must be under 17 years of age and present to the participating children's hospital within 7 days of their injury with a thermal burn covering <5% of their total body surface area. Facial and trivial burns will be excluded. Following a randomised controlled parallel design, participants will be allocated to either an active control or intervention group. The former will receive standard therapy consisting of Acticoat™ and Mepitel™. The intervention arm will be treated with silver-impregnated dressings in addition to NPWT via the RENASYS TOUCH™ vacuum pump. Participants' dressings will be changed every 3 to 5 days until their wounds are fully re-epithelialised. Time to re-epithelialisation will be studied as the primary outcome. Secondary outcomes will include pain, pruritus, wound progression, health-care-resource use (and costs), ease of management, treatment satisfaction and adverse events. Wound fluid collected during NPWT will also be analysed to generate a proteomic profile of the burn microenvironment.

DISCUSSION

The study will be the first randomised controlled trial to explore the clinical effects of NPWT on paediatric burns, with the aim of determining whether the therapy warrants implementation as an adjunct to standard burns management.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12618000256279 . Registered on 16 February 2018.

Negative Pressure Wound Therapy (Wound VAC) in the Treatment of Chylous Fistula After Neck Dissection

OBJECTIVES

Cervical chylous fistula is an uncommon but potentially severe occurrence associated with neck surgery. Methods for treating this problem have inconsistent efficacy and may result in lengthy hospital stays. Negative pressure wound therapy (NPWT) is a highly effective tool in the management of complex wounds. We report 3 cases where NPWT was successfully used to treat chylous fistulas following neck dissection.

METHODS

This is a retrospective chart review of 3 patients who developed chylous fistulas after neck dissection and were successfully treated with NPWT.

RESULTS

Chylous ouput ceased within 2 to 8 days of proper wound VAC placement. Hospital stays ranged from 6 to 47 days. Patients received altered diets, including TPN for 1 patient with high-flow output and nil-per-os (NPO) or clear liquids for the others. Patients received octreotide throughout their hospitalization.

CONCLUSION

NPWT shows potential as a treatment option for both high-volume and low-volume chylous fistulas following neck dissection.

Influence of negative pressure wound therapy on peri-prosthetic tissue vascularization and inflammation around porous titanium percutaneous devices

Negative Pressure Wound Therapy (NPWT) has been shown to limit downgrowth around percutaneous devices in a guinea pig model. However, the influence of NPWT on peri-prosthetic tissue characteristics leading to limited downgrowth is still unclear. In order to investigate this, 12 CD hairless rats were assigned into two groups, NPWT and Untreated (n = 6/group). Each animal was implanted with a porous coated titanium percutaneous device and was dressed with a gauze and semi-occlusive base dressing. Post-surgery, animals in the NPWT Group received a regimen of NPWT treatment (-70 to -90 mmHg). After 4 weeks, tissue was collected over the device and stained with CD31 and CD68 to quantify blood vessel density and inflammation, respectively. The device with the surrounding tissue was also collected to quantify downgrowth. NPWT treatment led to a 1.6-fold increase in blood vessel densities compared to untreated tissues (p < 0.05). NPWT treatment also resulted in half the downgrowth as the Untreated Group, although not statistically significant (p = 0.19). Additionally, the results showed a trend toward increased CD68 cell densities in the NPWT Group compared to the Untreated Group (p = 0.09). These findings suggest that NPWT may influence wound healing responses in percutaneous devices by increasing blood vessel densities, limiting downgrowth and potentially increasing inflammation. Overall, NPWT may enhance tissue vascularity around percutaneous devices, especially in patients with impaired wound healing. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2091-2101, 2019.

Vacuum assisted closure (VAC)/negative pressure wound therapy (NPWT) for difficult wounds: A review

Delayed wound healing particularly in difficult wounds and in elderly with co morbidities is a major concern. It leads to the pain, morbidity, prolonged treatment, and require major reconstructive surgery which imposes enormous social and financial burden. Vacuum-assisted closure (VAC) is an alternative method of wound management, which uses the negative pressure to prepare the wound for spontaneous healing or by lesser reconstructive options. Method of VAC application includes thorough debridement, adequate haemostasis and application of sterile foams dressing. A fenestrated tube is embedded in the foam and wound is sealed with adhesive tape to make it air tight. The fenestrate tube is connected to a vacuum pump with fluid collection container. The machine delivers continuous or intermittent suction, ranging from 50 to 125 mmHg. The VAC dressings are changed on 3rd day. Negative pressure therapy stabilizes the wound environment, reduces wound edema/bacterial load, improves tissue perfusion, and stimulates granulation tissue and angiogenesis. All this improves the possibility of primary closure of wounds and reduce the need for plastic procedures. VAC therapy appears to be a simple and more effective than conventional dressings for the management of difficult wound in terms of reduction in wound volume, depth, treatment duration and cost.

Effect of negative pressure wound therapy on molecular markers in diabetic foot ulcers

Diabetic foot ulcers are one of the most common complications of diabetes with high morbidity and mortality. Negative pressure wound therapy (NPWT) is one of the treatment modalities that facilitates the wound healing process; however, its molecular mechanism remains unclear. The aim of this study was to investigate the mechanism of action of NPWT in the treatment of diabetic foot ulcers via measuring the tissue expression of genes related to the wound healing process. The study included 40 patients with diabetic foot ulceration, 20 of them received NPWT and the other 20 were a control group treated with advanced moist therapy. Granulation tissue biopsies were obtained before and 10 days after treatment in both groups and subjected to real-time polymerase chain reaction to measure the mRNA expression of TGF-β1, VEGF, TNF-α, IL-1β, MMP-1, MMP-9 and TIMP-1 which are involved in the wound healing pathway. After 10 days of treatment with NPWT, the mRNA levels of IL-1β, TNF-α, MMP-1, and MMP-9 were significantly downregulated, while the levels of VEGF, TGF-β1 and TIMP-1 were significantly increased. Our study demonstrated that NPWT promotes wound healing in diabetic foot ulcers possibly by affecting growth factors, inflammatory cytokines, and matrix metalloproteinases.

Vakuumassistierte Wundbehandlung (Negative Pressure Wound Therapy, NPWT) in der Kleintiermedizin

Die Behandlung offener Wunden gehört zu den alltäglichen Herausforderungen in der Tiermedizin. In den letzten Jahren hat sich mit der vakuumassistierten Wundbehandlung (Negative Pressure Wound Therapy, NPWT) eine neue Therapieform entwickelt. Durch ihren Einsatz lassen sich die Heilung offener Wunden und die Einheilungsrate freier Hauttransplantate beim Kleintier signifikant verbessern. In diesem Überblick werden Wirkweise, Indikationen sowie Komplikationen der Negative Pressure Wound Therapy dargestellt.

Mechanical effects of negative pressure wound therapy on abdominal wounds - effects of different pressures and wound fillers

The mechanical deformation of the wound edge resulting from negative pressure wound therapy (NPWT) at the standard setting of around -120 mmHg has positive effects in promoting wound healing. However, it may cause pain to the patient during treatment. It is therefore important to study the mechanical effects of the wound edges using lower pressure and different wound fillers. Abdominal wounds were created on eight pigs. The wounds were sealed for NPWT using foam or gauze. Negative pressures between -20 and -160 mmHg were applied, and the decrease in wound diameter and the force with which the edges of the wound were drawn together (wound edge force) were measured. Increasing levels of negative pressure resulted in a gradual decrease in wound diameter and increase in wound edge force and reached a maximum at -120 mmHg, which is the pressure commonly used in clinical practice. Both the decrease in wound diameter and the increase in wound edge force was greater with foam than with gauze. A pressure of -80 mmHg has only 15% less effect than -120 mmHg, while a lower pressure (-40 mmHg) diminished the effects on diameter and force markedly. The NPWT-induced decrease in wound diameter and increase in wound edge force are greater at higher levels of negative pressure and when using foam than when using gauze as a wound filler. It may be possible to tailor the type of wound filler and level of negative pressure to obtain the best balance between wound healing and patient comfort.

Expression of MMP-8 in Pressure Injuries in Spinal Cord Injury Patients Managed by Negative Pressure Wound Therapy or Conventional Wound Care: A Randomized Controlled Trial

PURPOSE

The purpose of this study was to assess the level of matrix metalloproteinase-8 (MMP-8) and wound-healing outcome measures (length, width, and depth, exudate amount, and tissue type) in pressure injuries (PIs) of spinal cord-injured patients treated with negative pressure wound therapy (NPWT) using a novel negative pressure device versus PI treated with wet to moist gauze (conventional wound care).

DESIGN

Randomized controlled trial.

SUBJECTS AND SETTING

Forty-four spinal cord-injured patients with stage 3 and 4 sacral PI participated in the study. The study setting was the Department of Orthopedic Surgery at King George's Medical University, in Lucknow, India.

METHODS

Twenty two subjects were randomly allocated to undergo NPWT via a novel negative pressure device, and 22 participants received conventional wound dressing (wet to moist gauze dressings). Pressure injuries were treated for 9 weeks or until wound closure. Levels of MMP-8 were analyzed in the tissues of PIs at weeks 0, 3, 6, and 9 by enzyme-linked immunosorbent assay.

RESULTS

Significantly lower levels of MMP-8 were observed in the NPWT group at week 6 and week 9. There were no significant changes in the length and width of PIs between the groups till week 3. Significant reduced length and width were observed in PIs of patients in the NPWT group at week 6 (P = .04) and week 9 (P = .001). Similarly, significant reduction in the depth of PIs was observed in the NPWT group at week 9 (P < .05). At the end of 9 week, levels of MMP-8 showed a positive correlation with reduction in the length, width, and depth of PIs in the NPWT group while in the conventional dressing group, negative correlation was observed in association with MMP-8 and the length, width, and depth of PIs. Exudate levels were significantly lower in the NPWT group compared with the conventional dressing group from week 3 (2.96 ± 0.21 vs 2.62 ± 0.49); this difference persisted through week 9 (1.35 ± 0.75 vs 0.14 ± 0.35). Conversion of slough into red granulation tissue was significantly higher in the NPWT group after week 6 (P = .001).

CONCLUSION

Reduced levels of MMP-8 and an increased rate of healing were found in patients allocated to treatment with a novel negative pressure device as compared to wet to moist gauze conventional dressing. The novel NPWT device used in this study reduced exudate production and enhanced the rate of formation of red granulation tissue.

Negative pressure wound therapy versus gauze dressings for the treatment of contaminated traumatic wounds

OBJECTIVE

This compares hospital suction negative pressure wound therapy (NPWT) with conventional gauze dressings in traumatic soft-tissue injury at a tertiary care centre.

METHODS

A prospective control study was conducted between September 2012 and November 2014. Patients with one or more traumatic soft-tissue injuries with contaminated wounds were allocated to either a test group (received NPWT) or control group (received conventional gauze). Wounds were assessed by two orthopaedic surgeons. If grade A was achieved, the wound was covered with split-thickness skin graft, flap or delayed primary closure; otherwise, revision debridement and NPWT/saline gauze dressings were applied. Descriptive statistics (mean, standard deviation and proportions) were used to summarise the study variables. The 95% confidence intervals (CI) for difference of mean were used. Chi-square test and Fisher's exact test were used to observe an association between the qualitative data and outcome variables. Unpaired T-Test and Mann-Whitney U test were used for analysis of the quantitative data. A p<0.05 was considered statistically significant.

RESULTS

A total of 104 patients were included. The mean number of dressings per patient was significantly lower in the NPWT group (3.4) than in the control group (20.7) (p<0.001). The time between injury and complete closure (12.5 versus 21.4 days) as well as duration of hospital stay (17.3 versus 23.8 days) was significantly less in the NPWT group (p<0.05).

CONCLUSION

NPWT has a role in healing traumatic wounds and can be delivered effectively through hospital suction NPWT, which can also reduce the cost of therapy. We recommend its regular use in all patients presenting with post-traumatic, soft-tissue injuries when primary coverage is not possible.

Surgical Site Infection Rate Drops to 0% Using a Vacuum-Assisted Closure in Contaminated/ Dirty Infected Laparotomy Wounds

Wound site infections increase costs, hospital stay, morbidity, and mortality. Techniques used for wounds management after laparotomy are primary, delayed primary, and vacuum-assisted closures. The objective of this study is to compare infection rates between those techniques in contaminated and dirty/ infected wounds. Eighty-one laparotomized patients with Class III or IV surgical wounds were enrolled in a three-arm randomized prospective study. Patients were allocated to each group with the software Research Randomizer® (Urbaniak, G. C, & Plous, S., Version 4.0). Presence of infection was determined by a certified board physician according to Centers for Disease Control's Criteria for Defining a Surgical Site Infection. Twenty-seven patients received primary closure, 29 delayed primary closure, and 25 vacuum-assisted closure, with no exclusions for analysis. Surgical site infection was present in 10 (37%) patients treated with primary closure, 5 (17%) with primary delayed closure, and 0 (0%) patients receiving vacuum-assisted closure. Statistical significance was found between infection rates of the vacuum-assisted group and the other two groups. No significant difference was found between the primary and primary delayed closure groups. The infection rate in contaminated/dirty-infected laparotomy wounds decreases from 37 and 17 per cent with a primary and delayed primary closures, respectively, to 0 per cent with vacuum-assisted systems.

Amniotic membrane application for the healing of chronic wounds and ulcers

Wound healing usually follows a predictable sequence and prognosis of events. Its evolutionary process is the result of a complicated interaction between patient-related factors, the wound, the treatment used and the skills and knowledge of the professionals who treat them. Only through a meticulous initial assessment of the wound is it possible to identify the factors that contribute to its complexity. The challenge for professionals will be to implement efficient therapies at the right time and in the most cost-efficient way in order to reduce associated problems, treat the symptoms and expectations of the patients and achieve adequate wound healing whenever possible. This is particularly evident in big chronic wounds with considerable tissue loss, which become senescent in the process of inflammation or proliferation losing the ability to epithelialize. Generally, chronic wounds do not respond to current treatments, therefore they need special interventions. AM is a tissue of particular interest as a biological dressing and it has well-documented reepithelialization effects which are in part related to its capacity to synthesize and release biological active factors. Our studies have demonstrated that amniotic membrane (AM) is able to induce epithelialization in chronic wounds that were unable to epithelialize. AM induces several signaling pathways that are involved in cell migration and/or proliferation. Additionally, AM is able to selectively antagonize the anti-proliferative effect of transforming growth factor-ß (TGF-β) by modifying the genetic program that TGF-β induces on keratinocytes. The combined effect of AM on keratinocytes, promoting cell proliferation/migration and antagonizing the effect of TGF-β is the perfect combination, allowing chronic wounds to move out of their non-healing state and progress into epithelialization.

Evidence based review of negative pressure wound therapy

Vacuum-assisted closure, sometimes referred to as microdeformational wound therapy or most commonly negative pressure wound therapy (NPWT), has significantly improved wound care over the past two decades. NPWT is known to affect wound healing through four primary mechanisms (macrodeformation, microdeformation, fluid removal, and alteration of the wound environment) and various secondary mechanisms (including neurogenesis, angiogenesis, modulation of inflammation, and alterations in bioburden) which are described in this review. In addition, the technique has many established uses, for example in wound healing of diabetic and pressure ulcers, as well as burn and blast wounds. This therapy also has many uses whose efficacy has yet to be confirmed, for example the use in digestive surgery. Modifications of the traditional NPWT have also been established and are described in detail. This therapy has various considerations and contraindications which are summarized in this review. Finally, future perspectives, such as the optimal cycling of the treatment and the most appropriate interface material, are touched upon in the final segment. Overall, despite the fact that questions remain to be answered about NPWT, this technology is a major breakthrough in wound healing with significant potential use both in the hospital but also in the community.

A comparative study of negative pressure wound therapy with and without instillation of saline on wound healing

OBJECTIVE

Negative pressure wound therapy (NPWT) has become an established treatment of traumatic and infected wounds. Negative pressure wound therapy with instillation (NPWTi) is a further development that combines the conventional NPWT with instillation of different fluids which continuously administer therapeutic reagents to the wound. The aim of this study was to compare the impact of additional saline instillation in NPWTi to NPWT alone.

METHOD

Between January and July 2014, consecutive patients with acute wounds of the lower limb were treated with NPWTi with saline instillation. The number of revision surgeries, length of hospital stay, and duration of treatment until final healing were recorded and compared with matched patients undergoing NPWT without instillation.

RESULTS

There were 10 patients recruited with 10 matched controls examined restrospectivley. Patients who received NPWTi were found to have decreased time of hospitalisation (21.5 versus 26.5 days, p=0.43), and accelerated wound healing (9.0 versus 12.5 days, p=0.36) than patients who received NPWT. However, the difference in the outcomes of the patients who received NPWTi and patients who received NPWT was not found to be statisticallly significant.

CONCLUSION

NPWTi with instillation of saline is a promising method and its effectiveness needs to be tested in a randomised controlled trial compared with NPWT alone.

DECLARATION OF INTEREST

This study obtained support by KCI (Wiebsaden, Germany) for the surgical material.