Systematic review of molecular mechanism of action of negative-pressure wound therapy

Negative pressure wound therapy for treating foot wounds in people with diabetes mellitus

BACKGROUND

Foot wounds in people with diabetes mellitus (DM) are a common and serious global health issue. People with DM are prone to developing foot ulcers and, if these do not heal, they may also undergo foot amputation surgery resulting in postoperative wounds. Negative pressure wound therapy (NPWT) is a technology that is currently used widely in wound care. NPWT involves the application of a wound dressing attached to a vacuum suction machine. A carefully controlled negative pressure (or vacuum) sucks wound and tissue fluid away from the treated area into a canister. A clear and current overview of current evidence is required to facilitate decision-making regarding its use.

OBJECTIVES

To assess the effects of negative pressure wound therapy compared with standard care or other therapies in the treatment of foot wounds in people with DM in any care setting.

SEARCH METHODS

In January 2018, for this first update of this review, we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies, reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. We identified six additional studies for inclusion in the review.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that evaluated the effects of any brand of NPWT in the treatment of foot wounds in people with DM, irrespective of date or language of publication. Particular effort was made to identify unpublished studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction. Initial disagreements were resolved by discussion, or by including a third review author when necessary. We presented and analysed data separately for foot ulcers and postoperative wounds.

MAIN RESULTS

Eleven RCTs (972 participants) met the inclusion criteria. Study sample sizes ranged from 15 to 341 participants. One study had three arms, which were all included in the review. The remaining 10 studies had two arms. Two studies focused on postamputation wounds and all other studies included foot ulcers in people with DM. Ten studies compared NPWT with dressings; and one study compared NPWT delivered at 75 mmHg with NPWT delivered at 125 mmHg. Our primary outcome measures were the number of wounds healed and time to wound healing.NPWT compared with dressings for postoperative woundsTwo studies (292 participants) compared NPWT with moist wound dressings in postoperative wounds (postamputation wounds). Only one study specified a follow-up time, which was 16 weeks. This study (162 participants) reported an increased number of healed wounds in the NPWT group compared with the dressings group (risk ratio (RR) 1.44, 95% confidence interval (CI) 1.03 to 2.01; low-certainty evidence, downgraded for risk of bias and imprecision). This study also reported that median time to healing was 21 days shorter with NPWT compared with moist dressings (hazard ratio (HR) calculated by review authors 1.91, 95% CI 1.21 to 2.99; low-certainty evidence, downgraded for risk of bias and imprecision). Data from the two studies suggest that it is uncertain whether there is a difference between groups in amputation risk (RR 0.38, 95% CI 0.14 to 1.02; 292 participants; very low-certainty evidence, downgraded once for risk of bias and twice for imprecision).NPWT compared with dressings for foot ulcersThere were eight studies (640 participants) in this analysis and follow-up times varied between studies. Six studies (513 participants) reported the proportion of wounds healed and data could be pooled for five studies. Pooled data (486 participants) suggest that NPWT may increase the number of healed wounds compared with dressings (RR 1.40, 95% CI 1.14 to 1.72; I² = 0%; low-certainty evidence, downgraded once for risk of bias and once for imprecision). Three studies assessed time to healing, but only one study reported usable data. This study reported that NPWT reduced the time to healing compared with dressings (hazard ratio (HR) calculated by review authors 1.82, 95% CI 1.27 to 2.60; 341 participants; low-certainty evidence, downgraded once for risk of bias and once for imprecision).Data from three studies (441 participants) suggest that people allocated to NPWT may be at reduced risk of amputation compared with people allocated to dressings (RR 0.33, 95% CI 0.15 to 0.70; I² = 0%; low-certainty evidence; downgraded once for risk of bias and once for imprecision).Low-pressure compared with high-pressure NPWT for foot ulcersOne study (40 participants) compared NPWT 75 mmHg and NPWT 125 mmHg. Follow-up time was four weeks. There were no data on primary outcomes. There was no clear difference in the number of wounds closed or covered with surgery between groups (RR 0.83, 95% CI 0.47 to 1.47; very low-certainty evidence, downgraded once for risk of bias and twice for serious imprecision) and adverse events (RR 1.50, 95% CI 0.28 to 8.04; very low-certainty evidence, downgraded once for risk of bias and twice for serious imprecision).

AUTHORS' CONCLUSIONS

There is low-certainty evidence to suggest that NPWT, when compared with wound dressings, may increase the proportion of wounds healed and reduce the time to healing for postoperative foot wounds and ulcers of the foot in people with DM. For the comparisons of different pressures of NPWT for treating foot ulcers in people with DM, it is uncertain whether there is a difference in the number of wounds closed or covered with surgery, and adverse events. None of the included studies provided evidence on time to closure or coverage surgery, health-related quality of life or cost-effectiveness. The limitations in current RCT evidence suggest that further trials are required to reduce uncertainty around decision-making regarding the use of NPWT to treat foot wounds in people with DM.

Vacuum Sealing Drainage Therapy for Refractory Infectious Wound on 16 Renal Transplant Recipients

BACKGROUND

Refractory infectious wounds on renal transplantation (RT) recipients significantly prolong hospital stay, increase medical costs, and threaten allograft survival. Vacuum sealing drainage (VSD) therapy is a new technique for managing wounds based on the principle of application of controlled negative pressure. The aim of this study was to summarize the efficacy and safety of VSD therapy in the management of refractory infectious wounds following RT.

MATERIALS AND METHODS

This is a retrospective study of a cohort of 661 consecutive patients who received renal transplants over a period of 3 years in which the data were collected and analyzed retrospectively.

RESULTS

Out of the 661 patients, 16 (2.4%) developed refractory wound infection following RT. Nineteen organisms were identified by culture from all patients, including 10 patients infected with 1 or more bacteria, 2 patients with fungal infection, and 4 patients with both. Specifically, mucormycosis was demonstrated in 4 patients, pan-resistant Klebsiella pneumoniae in 2 patients, and Acinetobacter baumannii in 2 patients. All 16 patients were treated with VSD therapy for a median of 37 days (range, 6-111 days). The number of VSD sets used ranged from 4 to 28 sets (mean, 11.1 sets). A combination of antibiotics, debridement, and VSD therapy lead to 100% (16 of 16) wound healing. No VSD-relevant adverse events were observed.

CONCLUSIONS

VSD therapy is an effective and safe adjunct to conventional treatment modalities for the management of refractory wound infection following RT.

Successful wound treatment using negative pressure wound therapy without primary closure in a patient undergoing highly contaminated abdominal surgery

BACKGROUND

The indications for negative pressure wound therapy (NPWT) continue to expand, and NPWT has become a powerful tool for the treatment of interactive wounds. Recently, the use of NPWT over closed incisions has been shown to prevent surgical site infection (SSI) in patients undergoing contaminated or acute care surgery as prophylactic NPWT. In this article, we present our successful experience using NPWT without primary skin closure for wound treatment after a highly contaminated enterological surgery. The procedure we present in this case report is considerably different from the conventional prophylactic NPWT and a novel method in the field of gastrointestinal surgery.

CASE PRESENTATION

A 33-year-old man with Crohn's disease underwent a dirty, infected enterological surgical procedure for the treatment of abdominal wall abscess and multiple fistulas around his colonic stoma. The stoma reconstruction and wound debridement resulted in a broad skin defect, and the incision was strategically left open. In addition to the infected wound condition (class IV), Crohn's disease itself is a risk factor for SSI; consequently, we induced NPWT immediately after the surgery and closed the incision from both ends in a stepwise manner using sutures each time we changed the dressing. This procedure was effective, enabling complete healing and closure at the surgical site on postoperative day 14 without infection or a skin defect.

CONCLUSION

For highly contaminated enterological surgery, purposely leaving the incision open and starting NPWT immediately after the procedure is an effective strategy for early wound closure and the prevention of SSI.

Flap Reconstruction of the Abdominal Wall

Due to the abundant and lax tissue of the abdominal wall, most ventral trunk defects are amenable to local soft tissue closure. However, when abdominal defects are accompanied by a lack of soft tissue, the surgeon faces a more complex subset of reconstructions. Three important principles guide the reconstruction of these wounds: timing of closure, careful assessment of the true extent of the wound, and the components of the defect. This article focuses on these three guiding principles and suggests the authors' preferred technique for these difficult defects.

Negative pressure wound therapy for open traumatic wounds

BACKGROUND

Traumatic wounds (wounds caused by injury) range from abrasions and minor skin incisions or tears, to wounds with extensive tissue damage or loss as well as damage to bone and internal organs. Two key types of traumatic wounds considered in this review are those that damage soft tissue only and those that involve a broken bone, that is, open fractures. In some cases these wounds are left open and negative pressure wound therapy (NPWT) is used as a treatment. This medical device involves the application of a wound dressing through which negative pressure is applied and tissue fluid drawn away from the area. The treatment aims to support wound management, to prepare wounds for further surgery, to reduce the risk of infection and potentially to reduce time to healing (with or without surgical intervention). There are no systematic reviews assessing the effectiveness of NPWT for traumatic wounds.

OBJECTIVES

To assess the effects of NPWT for treating open traumatic wounds in people managed in any care setting.

SEARCH METHODS

In June 2018 we searched the Cochrane Wounds Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

Published and unpublished randomised controlled trials that used NPWT for open traumatic wounds involving either open fractures or soft tissue wounds. Wound healing, wound infection and adverse events were our primary outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible studies, extracted data, carried out a 'Risk of bias' assessment and rated the certainty of the evidence. Data were presented and analysed separately for open fracture wounds and other open traumatic wounds (not involving a broken bone).

MAIN RESULTS

Seven RCTs (1377 participants recruited) met the inclusion criteria of this review. Study sample sizes ranged from 40 to 586 participants. One study had three arms, which were all included in the review. Six studies compared NPWT at 125 mmHg with standard care: one of these studies did not report any relevant outcome data. One further study compared NPWT at 75 mmHg with standard care and NPWT 125mmHg with NPWT 75 mmHg.Open fracture wounds (four studies all comparing NPWT 125 mmHg with standard care)One study (460 participants) comparing NPWT 125 mmHg with standard care reported the proportions of wounds healed in each arm. At six weeks there was no clear difference between groups in the number of participants with a healed, open fracture wound: risk ratio (RR) 1.01 (95% confidence interval (CI) 0.81 to 1.27); moderate-certainty evidence, downgraded for imprecision.We pooled data on wound infection from four studies (596 participants). Follow-up varied between studies but was approximately 30 days. On average, it is uncertain whether NPWT at 125 mmHg reduces the risk of wound infection compared with standard care (RR 0.48, 95% CI 0.20 to 1.13; I2 = 56%); very low-certainty evidence downgraded for risk of bias, inconsistency and imprecision.Data from one study shows that there is probably no clear difference in health-related quality of life between participants treated with NPWT 125 mmHg and those treated with standard wound care (EQ-5D utility scores mean difference (MD) -0.01, 95% CI -0.08 to 0.06; 364 participants, moderate-certainty evidence; physical component summary score of the short-form 12 instrument MD -0.50, 95% CI -4.08 to 3.08; 329 participants; low-certainty evidence downgraded for imprecision).Moderate-certainty evidence from one trial (460 participants) suggests that NPWT is unlikely to be a cost-effective treatment for open fractures in the UK. On average, NPWT was more costly and conferred few additional quality-adjusted life years (QALYs) when compared with standard care. The incremental cost-effectiveness ratio was GBP 267,910 and NPWT was shown to be unlikely to be cost effective at a range of cost-per-QALYs thresholds. We downgraded the certainty of the evidence for imprecision.Other open traumatic wounds (two studies, one comparing NPWT 125 mmHg with standard care and a three-arm study comparing NPWT 125 mmHg, NPWT 75 mmHg and standard care)Pooled data from two studies (509 participants) suggests no clear difference in risk of wound infection between open traumatic wounds treated with NPWT at 125 mmHg or standard care (RR 0.61, 95% CI 0.31 to 1.18); low-certainty evidence downgraded for risk of bias and imprecision.One trial with 463 participants compared NPWT at 75 mmHg with standard care and with NPWT at 125 mmHg. Data on wound infection were reported for each comparison. It is uncertain if there is a difference in risk of wound infection between NPWT 75 mmHg and standard care (RR 0.44, 95% CI 0.17 to 1.10; 463 participants) and uncertain if there is a difference in risk of wound infection between NPWT 75 mmHg and 125 mmHg (RR 1.04, 95% CI 0.31 to 3.51; 251 participants. We downgraded the certainty of the evidence for risk of bias and imprecision.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence for no clear difference between NPWT and standard care on the proportion of wounds healed at six weeks for open fracture wounds. There is moderate-certainty evidence that NPWT is not a cost-effective treatment for open fracture wounds. Moderate-certainty evidence means that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. It is uncertain whether there is a difference in risk of wound infection, adverse events, time to closure or coverage surgery, pain or health-related quality of life between NPWT and standard care for any type of open traumatic wound.

Standard wound management versus negative-pressure wound therapy in the treatment of adult patients having surgical incisions for major trauma to the lower limb-a two-arm parallel group superiority randomised controlled trial: protocol for Wound Healing in Surgery for Trauma (WHIST)

INTRODUCTION

Patients with closed high-energy injuries associated with major trauma have surprisingly high rates of surgical site infection in incisions created during fracture fixation. One factor that may reduce the risk of surgical site infection is the type of dressing applied over the closed surgical incision. In this multicentre randomised clinical trial, negative-pressure wound therapy will be compared with standard dressings with outcomes of deep infection, quality of life, pain and disability.

METHODS AND ANALYSIS

Adult patients presenting to hospital within 72 hours of sustaining major trauma, requiring a surgical incision to treat a fractured lower limb, are eligible for inclusion. Randomisation, stratified by trial centre, open/closed fracture at presentation and Injury Severity Score (ISS) ≤15 versus ISS ≥16 will be administered via a secure web-based service using minimisation. The random allocation will be to either standard wound management or negative-pressure wound therapy.Trial participants will usually have clinical follow-up at the local fracture clinic for a minimum of 6 months, as per standard National Health Service practice. Diagnosis of deep infection will be recorded at 30 days. Functional, pain and quality of life outcome data will be collected using the Disability Rating Index, Douleur Neuropathique Questionnaire and Euroqol - 5 Dimension - 5 level (EQ-5D-5L) questionnaires at 3 months and 6 months postinjury. Further data will be captured on resource use and any late postoperative complications.Longer term outcomes will be assessed annually for 5 years and reported separately.

ETHICS AND DISSEMINATION

National Research Ethics Committee approved this study on 16 February 2016 16/WM/0006.The National Institute for Health Research Health Technology Assessment monograph and a manuscript to a peer-reviewed journal will be submitted on completion of this trial. The results of this trial will inform clinical practice on the clinical and cost-effectiveness of the treatment of this injury.

TRIAL REGISTRATION NUMBER

ISRCTN12702354; Pre-results.

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.

Dysregulation of wound healing mechanisms in diabetes and the importance of negative pressure wound therapy (NPWT)

Diabetes is a serious disease with severe side effects and comorbidities. Diabetic foot with its chronic nonhealing ulcers, or diabetic foot ulcers, as they are commonly called, can be devastating, even leading to amputation. Many therapies exist to assist and improve wound healing. One exciting discovery is the use of negative pressure wound therapy (NPWT) as an adjunct to standard treatment. Few studies have substantively explored the molecular mechanisms of NPWT and why we see improved wound healing, a concept that demands more research. The following commentary summarizes the current literature regarding NPWT as well as some of the vast body of work that focuses on the physiologic mechanisms of wound healing in diabetics in general.

Negative pressure wound therapy: Regulating blood flow perfusion and microvessel maturation through microvascular pericytes

Negative pressure wound therapy (NPWT) has been demonstrated to accelerate wound healing by promoting angiogenesis. However, whether blood flow perfusion is regulated by microvessel maturation and pericytes following NPWT remains unclear, as well as the exact association between pericytes and collagen type IV. The aim of this study was to investigate the relevant association between blood flow perfusion and microvessel maturation and pericytes following NPWT, and to further explore the underlying molecular mechanisms. We also aimed to investigate the association between pericytes and collagen type IV. For this purpose, we created a rat model of diabetic wounds and microvascular blood flow perfusion was detected using a laser Doppler blood perfusion imager. The expression levels of angiogenin-1, tyrosine phosphorylation of tyrosine kinase receptor-2 (Tie-2), α-smooth muscle actin (α-SMA) and collagen type IV were detected and analyzed through immunohistochemistry, immunofluorescence, RT-qPCR and western blot analysis. The results revealed that NPWT promoted the overexpression of angiogenin-1, Tie-2, α-SMA and collagen type IV, and significantly increased blood flow perfusion coupled with microvessel maturation in the NPWT group at the later stages (7–10 days) of wound healing. Our results suggested that NPWT can preferentially enhance vessel maturation and increase the number of pericytes, thus regulating blood flow perfusion. On the other hand, pericytes and collagen type IV had a mutual interaction, promoting microvessel maturation.

Safety and efficacy of prophylactic negative pressure wound therapy following open saphenous vein harvest in cardiac surgery: a feasibility study

Objectives

Surgical site complications following great saphenous vein (GSV) harvest presents a significant risk of morbidity. Negative pressure wound therapy (NPWT) has shown promise in the treatment and prophylaxis of open wounds and surgical incisions but has not been studied following GSV harvest. We performed a feasibility study examining the use of NPWT following GSV harvest for coronary bypass surgery.

Methods

Sixty-four patients were recruited in this single-centre, single-blind, randomized controlled trial. The primary endpoint assessed feasibility by examining rates of device complication and malfunction. Secondary endpoints included rates of surgical site infection, lower leg complications, discharge date, and quality of life at discharge and 6 weeks. NPWT was delivered using the Prevena NPWT device.

Results

There were no complications associated with NPWT which required intervention aside from discontinuation. NPWT was tolerated in 91% (30/33) of patients for the duration of treatment with an average of 4.8 days (±1.45 days). Device malfunction which required discontinuation was 6% (2/33) and involved a malfunctioning pressure sensor and did not affect patient care or present safety concerns. One patient had allergic contact dermatitis to the adhesive and had the device removed. NPWT patients had an earlier date of discharge (6 vs 10 days, P = 0.008), increased ability for self-care ( P = 0.0234) and quality of life ( P = 0.039) at initial assessment, and increased mobility at initial and follow-up assessment ( P = 0.0117 and 0.0123).

Conclusions

The use of NPWT following GSV harvest is safe, well tolerated and improves postoperative recovery with prolonged impact on mobility at 6 weeks.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT01698372 ; registration number: NCT01698372.

Effect of Negative Pressure Wound Therapy on Cellular Fibronectin and Transforming Growth Factor-β1 Expression in Diabetic Foot Wounds

BACKGROUND

Chronic diabetic foot wounds are a leading cause of amputation, morbidity, and hospitalization for patients with diabetes. Negative-pressure wound therapy (NPWT) can putatively facilitate wound healing, but the underlying mechanisms remain unclear. Cellular fibronectin (cFN) and transforming growth factor-β1 (TGF-β1) play an important role in wound healing. This prospective randomized controlled trial evaluated the effects of NPWT on the production of cFN and the expression of TGF-β1 in diabetic foot wounds of patients.

METHODS

From January 2012 to January 2015, 40 patients with diabetic foot wounds were randomly and equally apportioned to receive either NPWT or advanced moist wound therapy (control) for 7 days. Granulation tissue was harvested before and after treatment. Immunohistochemistry and Western blot were performed to evaluate protein levels of cFN and TGF-β1, and real-time polymerase chain reaction (PCR) to measure corresponding mRNA expressions.

RESULTS

NPWT facilitated the expression of cFN and TGF-β1 in diabetic foot wounds. Immunohistochemical analysis revealed higher levels of cFN and TGF-β1 in the NPWT group than in the control group. Western blot and real-time PCR analysis further showed that protein and mRNA levels of cFN or TGF-β1 were higher in the NPWT group than that in the control group ( P < .01, both).

CONCLUSION

Our results showed that NPWT facilitated the production of cFN and the expression of TGF-β1 in granulation tissue in diabetic foot ulcers.

LEVEL OF EVIDENCE

Level I, randomized controlled study.

European Association for Cardio-Thoracic Surgery expert consensus statement on the prevention and management of mediastinitis

Mediastinitis continues to be an important and life-threatening complication after median sternotomy despite advances in prevention and treatment strategies, with an incidence of 0.25-5%. It can also occur as extension of infection from adjacent structures such as the oesophagus, airways and lungs, or as descending necrotizing infection from the head and neck. In addition, there is a chronic form of 'chronic fibrosing mediastinitis' usually caused by granulomatous infections. In this expert consensus, the evidence for strategies for treatment and prevention of mediatinitis is reviewed in detail aiming at reducing the incidence and optimizing the management of this serious condition.

The effect of adhesives on inflammatory immune-markers during renal injury healing

Renal injury is common in abdominal trauma. Adhesives and sealants can be used to repair and preserve damaged organs. We describe the effect of three biomaterial treatments (TachoSil, GelitaSpon, and Adhflex) on injured renal tissue. Renal traumatic injuries were experimentally induced in male Wistar rats (n = 90) using a punch. Animals were divided into five groups: (1) sham noninjured (n = 3) and punch injury groups; (2) nontreated (n = 6); (3) TachoSil (n = 27); (4) GelitaSpon (n = 27); and (5) Adhflex (n = 27). Wound healing was evaluated 2, 6, and 18 days postinjury by inflammatory cytokines response, histopathological evolution of lesions, inflammatory reaction markers (CD68), and vascular neoformation (CD31). The TachoSil group showed the least inflammatory reaction among the three treated groups, which showed similarly low inflammatory reaction 18 days postinjury. Ciliary neurotrophic factor, soluble intercellular adhesion molecule-1, L-selectin, thymus chemokine, and TIMP metallopeptidase inhibitor 1 expression peaked between 2 and 6 days postinjury. TachoSil promoted the highest cytokine expression. The Adhflex group had the highest CD31 inflammatory immune-marker levels at 2 and 6 days postinjury, but there was a similar decrease in CD31 levels in all three groups at 18 days postinjury. The results show that all three sealant treatments induced a normal healing process with the typical pattern of proinflammatory cytokine and immune-marker expression. Each tested sealant substance could be suitable treatment for renal lacerations. The findings of this study indicate that Adhflex^® elastic cyanoacrylate does not induce an adverse inflammatory reaction, and therefore, could be considered as one of the first-line treatments for renal injuries. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1444-1455, 2018.

A novel facilitated negative-pressure wound therapy for thoracic incision infection after esophagectomy

BACKGROUND

Negative-pressure wound therapy (NPWT) is the therapeutic management of traumatic soft-tissue wounds and infections. The efficacy of NPWT in the treatment of thoracic incision infection is unclear. We assess the effectiveness and safety of a novel facilitated NPWT for thoracic incision infection after esophagectomy.

METHODS

Between Jan. 2013 and Mar. 2016, 380 patients underwent open esophagectomy in our department. Forty-five patients with thoracic incision infection were retrospectively reviewed. Of these patients, 25 were treated with NPWT and 20 patients were treated with open wound dressing. The patients' clinical demographic data, postoperative outcomes and wound treatment cost are reviewed.

RESULTS

The thoracic incision infection rate was 11.8%. All of the incision infections were cured in the hospital or on an outpatient basis. No allergic reactions or other side effects occurred with NPWT. Although the patients who were treated with NPWT did not have a significantly shorter postoperative hospital stay than those treated with open wound dressing (P=0.092), the use of NPWT therapy for thoracic incision infection led to a shorter wound healing times (13 vs. 20 days; P=0.004) and a lower wound treatment cost (P=0.020).

CONCLUSIONS

Thoracic incision infection is a common complication of esophagectomy. NPWT is a safe and effective therapeutic management for thoracic incision infection that is associated with shortened wound healing times and reduced wound treatment costs than traditional open wound treatment.

Injectable Pore-Forming Hydrogel Scaffolds for Complex Wound Tissue Engineering: Designing and Controlling Their Porosity and Mechanical Properties

Traumatic soft tissue wounds present a significant reconstructive challenge. The adoption of closed-circuit negative pressure wound therapy (NPWT) has enabled surgeons to temporize these wounds before reconstruction. Such systems use porous synthetic foam scaffolds as wound fillers at the interface between the negative pressure system and the wound bed. The idea of using a bespoke porous biomaterial that enhances wound healing, as filler for an NPWT system, is attractive as it circumvents concerns regarding reconstructive delay and the need for dressing changes that are features of the current systems. Porous foam biomaterials are mechanically robust and able to synthesize in situ. Hence, they exhibit potential to fulfill the niche for such a functionalized injectable material. Injectable scaffolds are currently in use for minimally invasive surgery, but the design parameters for large-volume expansive foams remain unclear. Potential platforms include hydrogel systems, (particularly superabsorbent, superporous, and nanocomposite systems), polyurethane-based moisture-cured foams, and high internal phase emulsion polymer systems. The aim of this review is to discuss the design parameters for such future biomaterials and review potential candidate materials for further research into this up and coming field.

Systematic review of the negative pressure wound therapy in kidney transplant recipients

AIM

To review negative pressure wound therapy (NPWT) as an important addition to the conventional methods of wound management.

METHODS

A systematic review, performed by searching the PubMed, EMBASE and Cochrane Library databases, showed 11 case reports comprising a total of 22 kidney transplantation (KT) patients (range, 1 to 9), who were treated with NPWT. Application of NPWT was associated with successful healing of wounds, leg ulcer, lymphocele and urine leak from ileal conduit.

RESULTS

No complications related to NPWT were reported. However, there was paucity of robust data on the effectiveness of NPWT in KT recipients; therefore, prospective studies assessing its safety and efficacy of NPWT and randomised trials comparing the effectiveness of NPWT with alternative modalities of wound management in KT recipients is recommended.

CONCLUSION

Negative pressure incision management system, NPWT with instillation and endoscopic vacuum-assisted closure system are in investigational stage.

The use of a negative pressure wound management system in perineal wound closure after extralevator abdominoperineal excision (ELAPE) for low rectal cancer

BACKGROUND

Perineal wound healing is a significant challenge after extralevator abdominoperineal excision (ELAPE) due to a high rate of wound breakdown. Negative pressure therapy has proven benefits in open wounds, and recently a negative pressure system has been developed for use on closed wounds at high risk of breakdown, such as apronectomy and hysterectomy. The aim of the present study was to determine whether negative pressure therapy applied to closed perineal wounds after ELAPE improved wound healing and compare outcomes to the published literature and outcomes from a historical cohort of patients who had undergone 'standard' abdominoperineal resection (APR) and primary closure of the perineal wounds.

METHODS

Prospective data on consecutive patients having ELAPE in the period from November 2012 to April 2015 were collected. The pelvic floor defect was reconstructed with biologic mesh. The adipose tissue layer was closed with vicryl sutures, a suction drain was left in the deep layer, the subcuticular layer and skin were closed, and the negative pressure system was applied. Any wound breakdown within the first 30 days postoperatively was recorded.

RESULTS

Of the 32 consecutive ELAPE patients whose perineal wounds were closed within 30 days with the use of the negative pressure system, there was 1 patient with major perineal wound breakdown and 2 patients with a 1 cm superficial wound defect, which needed no further treatment. In the remaining 29 (90 %) patients, the perineal wounds healed fully without complications. Twenty-five patients underwent standard APR in 2010-2011 with primary closure of their perineal wounds. Ten out of 25(40 %) of patients who had undergone standard APR and primary closure of perineal wounds had major wound complications (p = 0.01).

CONCLUSIONS

Our results suggest that after ELAPE the application of a negative pressure system to the perineal wound closed with biologic mesh may reduce perineal wound complications and may reduce the need for major perineal reconstruction.

Mesenchymal Stem Cells in Chronic Wounds: The Spectrum from Basic to Advanced Therapy

Significance: Almost 7 million Americans have chronic cutaneous wounds and billions of dollars are spent on their treatment. The number of patients with nonhealing wounds keeps increasing worldwide due to an ever-aging population, increasing number of obese and diabetic patients, and cardiovascular disease. Recent Advances: Advanced treatments for difficult wounds are needed. Therapy with mesenchymal stem cells (MSCs) is attractive due to their differentiating potential, their immunomodulating properties, and their paracrine effects. Critical Issues: New technologies (including growth factors and skin substitutes) are now widely used for stimulating wound healing. However, in spite of these advances, the percentage of complete wound closure in most clinical situations is around 50-60%. Moreover, there is a high rate of wound recurrence. Future Directions: Recently, it has been demonstrated that MSCs speed up wound healing by decreasing inflammation, by promoting angiogenesis, and by decreasing scarring. However, there are some potential limitations to successful MSC therapy. These limitations include the need to improve cell delivery methods, cell viability, heterogeneity in MSC preparations, and suboptimal wound bed preparation. Further large, controlled clinical trials are needed to establish the safety of MSCs before widespread clinical application.

Complicated Skin and Skin Structure Infection After Erysipelas

Erysipelas are common soft tissue infections responding to first-line antibiosis. Because of factors of related to responsible bacteria and host, complications can occur that need extensive surgery in addition to intensified drug therapy. We report on a 65-year-old woman with leg ulcer who developed an absceding and necrotizing panniculitis of the affected leg complicating erysipelas. Escherichia coli and Pseudomonas aeruginosa were identified. Debridement and surgical removal of inflamed subcutaneous adipose tissue was decisive to interrupt the process. Wound bed preparation was realized by vacuum-assisted closure. Final wound closure was done by split-skin mesh graft. Complicated skin and skin structure infections need a combined approach of intensified antibiosis and surgery to save life.

Negative pressure wound therapy for serious dog bites of extremities: a prospective randomized trial

OBJECTIVES

The objectives were to investigate the emergency treatment of serious dog bite lacerations on limbs and to identify whether negative pressure wound therapy (NPWT) was beneficial in these instances.

METHODS

A total of 580 cases with serious limb lacerations due to dog bites were randomly divided into 2 groups. After thorough debridement, the limb lacerations of group A (n = 329) were left open. The remaining cases (n = 251) were randomly divided into 2 subgroups, group B and group C, which were treated with 125 and 75 mm Hg of continuous negative pressure, respectively. Antibiotics were only used in cases where there were systemic signs of wound infection, and were not given prophylactically. The infection rate, infection time, and healing time were analyzed.

RESULTS

The wound infection rates of groups A, B, and C were 9.1%, 4.1%, and 3.9%, respectively. The infection times of the 3 groups were 26.3 ± 11.6, 159.8 ± 13.4, and 166.4 ± 16.2 hours, respectively. The recovery times of the infection patients in the 3 groups were 19.2 ± 4.6, 13.2 ± 2.1, and 12.7 ± 2.3 days, respectively, and in the noninfection patients, the recovery times were 15.6 ± 2.7, 10.1 ± 2.3, and 10.5 ± 1.9 days, respectively. In groups B (-125 mm Hg) and C (-75 mm Hg), the infection rate, infection time, and healing time showed no significant differences.

CONCLUSION

Patients with serious dog bite laceration on limbs could benefit from NPWT. Compared with the traditional treatment of leaving the wounds open, NPWT reduced the infection rate and shortened recovery time. When NPWT was performed, low negative pressure (-75 mm Hg) had the same positive effects as high pressure (-125 mm Hg). Prophylactic antibiotics administration is not recommended for treating this kind of laceration.

LEVEL OF EVIDENCE

Therapeutic/care management, level II.

Role of negative pressure wound therapy in total hip and knee arthroplasty

Negative-pressure wound therapy (NPWT) has been a successful modality of wound management which is in widespread use in several surgical fields. The main mechanisms of action thought to play a role in enhancing wound healing and preventing surgical site infection are macrodeformation and microdeformation of the wound bed, fluid removal, and stabilization of the wound environment. Due to the devastating consequences of infection in the setting of joint arthroplasty, there has been some interest in the use of NPWT following total hip arthroplasty and total knee arthroplasty. However, there is still a scarcity of data reporting on the use of NPWT within this field and most studies are limited by small sample sizes, high variability of clinical settings and end-points. There is little evidence to support the use of NPWT as an adjunctive treatment for surgical wound drainage, and for this reason surgical intervention should not be delayed when indicated. The prophylactic use of NPWT after arthroplasty in patients that are at high risk for postoperative wound drainage appears to have the strongest clinical evidence. Several clinical trials including single-use NPWT devices for this purpose are currently in progress and this may soon be incorporated in clinical guidelines as a mean to prevent periprosthetic joint infections.

Negative pressure wound therapy limits downgrowth in percutaneous devices

Maintenance of a soft tissue seal around percutaneous devices is challenged by the downgrowth of periprosthetic tissues-a gateway to potential infection. As negative pressure wound therapy (NPWT) is used clinically to facilitate healing of complex soft tissue pathologies, it was hypothesized that NPWT could limit downgrowth of periprosthetic tissues. To test this hypothesis, 20 hairless guinea pigs were randomly assigned into four groups (n = 5/group). Using a One-Stage (Groups 1 and 3) or a Two-Stage (Groups 2 and 4) surgical procedure, each animal was implanted with a titanium-alloy subdermal device porous-coated with commercially pure, medical grade titanium. Each subdermal device had a smooth titanium-alloy percutaneous post. The One-Stage procedure encompassed insertion of a fully assembled device during a single surgery. The Two-Stage procedure involved the implantation of a subdermal device during the first surgery, and then three weeks later, insertion of a percutaneous post. Groups 1 and 2 served as untreated controls and Groups 3 and 4 received NPWT. Four weeks postimplantation of the post, the devices and surrounding tissues were harvested, and histologically evaluated for downgrowth. Within the untreated control groups, the Two-Stage surgical procedure significantly decreased downgrowth (p = 0.027) when compared with the One-Stage procedure. Independent of the surgical procedures performed, NPWT significantly limited downgrowth (p ≤ 0.05) when compared with the untreated controls.

Negative pressure wound therapy for high-risk wounds in lower extremity revascularization: study protocol for a randomized controlled trial

Background

Rates of surgical site infections (SSIs) following groin incision for femoral artery exposure are much higher than expected of a clean operation. The morbidity and mortality is high, particularly with the use of prosthetic grafts. The vascular surgery population is at an increased risk of SSIs related to peripheral vascular disease (PVD), diabetes, obesity, previous surgery and presence of tissue loss. Negative pressure wound therapy (NPWT) dressings have been used on primarily closed incisions to reduce surgical site infections in other surgical disciplines. We have not come across any randomized controlled trials to support the prophylactic use of negative pressure wound therapy in high-risk vascular patients undergoing lower limb revascularization.

Methods/design

In this single-center, prospective randomized controlled trial, patients scheduled for a lower limb revascularization requiring open femoral artery exposure who are at a high risk (BMI > 30 kg/m², previous femoral cutdown or Rutherford V or VI category for chronic limb ischemia) will be eligible for the study. A total of 108 groin incisions will be randomized to the use of a negative pressure wound device or standard adhesive gauze dressing. Patients will be followed in hospital and reassessed within the first 30 days postoperatively. The primary outcome is SSI within the first 30 days of surgery and will be determined using the intention-to-treat principle. Secondary outcomes include length of stay, emergency room visits, reoperation, amputation and mortality. A cost analysis will be performed.

Discussion

The trial is expected to define the role of NPWT in SSI prophylaxis for lower limb revascularization in high-risk vascular patients. The results of the study will be used to inform current best practice for perioperative care and the minimization of SSIs.

Trial registration

NCT02084017, March 2014