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

Treatment of Breast Cancer-Related Lymphedema Using Negative Pressure Massage: A Pilot Randomized Controlled Trial

OBJECTIVE

To evaluate the efficacy of negative pressure massage treatment (NPMT) compared with manual lymphatic drainage (MLD) in women with chronic breast cancer-related lymphedema (LE). We hypothesized that NPMT would result in greater improvements in LE and upper limb function.

DESIGN

Pilot single-blinded randomized controlled trial.

SETTING

Health sciences university.

PARTICIPANTS

Of 64 women screened, 28 met eligibility requirements (ie, >18y of age; completed active treatment for breast cancer; had unilateral arm LE for ≥1y; were not receiving LE care; had stable LE) and were randomized to the NPMT (n=15) and control groups (n=13).

INTERVENTIONS

The intervention group received NPMT and the control group received MLD; both received twelve 60-minute sessions over 4-6 weeks.

MAIN OUTCOME MEASURES

Bioimpedance (lymphedema index [L-Dex] units]), limb volume (mL) calculated from limb circumference, and Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH) score.

RESULTS

Outcomes were analyzed for 28 women. Compared to the MLD group, the NPMT group demonstrated greater improvement with a large effect size in L-Dex scores (P=.001; standardized mean difference [SMD]=-1.15; 95% confidence interval, -1.96 to -0.35) and interlimb volume differences (P=.038; SMD=-0.83; 95% confidence interval, -1.60 to -0.05). Differences in DASH scores were not statistically significant (P=.067).

CONCLUSIONS

Compared to MLD, treatment with NPMT resulted in greater improvement in L-Dex scores and interlimb volume differences in women with a duration of unilateral upper limb LE of >1 year. Our findings need to be confirmed in a larger randomized controlled trial.

Biofilm-Innate Immune Interface: Contribution to Chronic Wound Formation

Delayed wound healing can cause significant issues for immobile and ageing individuals as well as those living with co-morbid conditions such as diabetes, cardiovascular disease, and cancer. These delays increase a patient’s risk for infection and, in severe cases, can result in the formation of chronic, non-healing ulcers (e.g., diabetic foot ulcers, surgical site infections, pressure ulcers and venous leg ulcers). Chronic wounds are very difficult and expensive to treat and there is an urgent need to develop more effective therapeutics that restore healing processes. Sustained innate immune activation and inflammation are common features observed across most chronic wound types. However, the factors driving this activation remain incompletely understood. Emerging evidence suggests that the composition and structure of the wound microbiome may play a central role in driving this dysregulated activation but the cellular and molecular mechanisms underlying these processes require further investigation. In this review, we will discuss the current literature on: 1) how bacterial populations and biofilms contribute to chronic wound formation, 2) the role of bacteria and biofilms in driving dysfunctional innate immune responses in chronic wounds, and 3) therapeutics currently available (or underdevelopment) that target bacteria-innate immune interactions to improve healing. We will also discuss potential issues in studying the complexity of immune-biofilm interactions in chronic wounds and explore future areas of investigation for the field.

Application of negative tissue interstitial pressure improves functional capillary density after hemorrhagic shock in the absence of volume resuscitation

Microvascular fluid exchange is primarily dependent on Starling forces and both the active and passive myogenic response of arterioles and post-capillary venules. Arterioles are classically considered resistance vessels, while venules are considered capacitance vessels with high distensibility and low tonic sympathetic stimulation at rest. However, few studies have investigated the effects of modulating interstitial hydrostatic pressure, particularly in the context of hemorrhagic shock. The objective of this study was to investigate the mechanics of arterioles and functional capillary density (FCD) during application of negative tissue interstitial pressure after 40% total blood volume hemorrhagic shock. In this study, we characterized systemic and microcirculatory hemodynamic parameters, including FCD, in hamsters instrumented with a dorsal window chamber and a custom-designed negative pressure application device via intravital microscopy. In large arterioles, application of negative pressure after hemorrhagic shock resulted in a 13 ± 11% decrease in flow compared with only a 7 ± 9% decrease in flow after hemorrhagic shock alone after 90 minutes. In post-capillary venules, however, application of negative pressure after hemorrhagic shock resulted in a 31 ± 4% decrease in flow compared with only an 8 ± 5% decrease in flow after hemorrhagic shock alone after 90 minutes. Normalized FCD was observed to significantly improve after application of negative pressure after hemorrhagic shock (0.66 ± 0.02) compared to hemorrhagic shock without application of negative pressure (0.50 ± 0.04). Our study demonstrates that application of negative pressure acutely improves FCD during hemorrhagic shock, though it does not normalize FCD. These results suggest that by increasing the hydrostatic pressure gradient between the microvasculature and interstitium, microvascular perfusion can be transiently restored in the absence of volume resuscitation. This study has significant clinical implications, particularly in negative pressure wound therapy, and offers an alternative mechanism to improve microvascular perfusion during hypovolemic shock.

Negative pressure wound therapy does not diminish efficacy of topical antibiotic powder in a preclinical contaminated wound model

AIMS

High-energy injuries can result in multiple complications, the most prevalent being infection. Vancomycin powder has been used with increasing frequency in orthopaedic trauma given its success in reducing infection following spine surgery. Additionally, large, traumatic injuries require wound coverage and management by dressings such as negative pressure wound therapy (NPWT). NPWT has been shown to decrease the ability of antibiotic cement beads to reduce infection, but its effect on antibiotic powder is not known. The goal of this study was to determine if NPWT reduces the efficacy of topically applied antibiotic powder.

METHODS

Complex musculoskeletal wounds were created in goats and inoculated with a strain of Staphylococcus aureus modified to emit light. Six hours after contaminating the wounds, imaging, irrigation, and debridement and treatment application were performed. Animals received either vancomycin powder with a wound pouch dressing or vancomycin powder with NPWT.

RESULTS

There were no differences in eradication of bacteria when vancomycin powder was used in combination with NPWT (4.5% of baseline) compared to vancomycin powder with a wound pouch dressing (1.7% of baseline) (p = 0.986), even though approximately 50% of the vancomycin was recovered in the NPWT exudate canister.

CONCLUSION

The antimicrobial efficacy of the vancomycin powder was not diminished by the application of NPWT. These topical and locally applied therapies are potentially effective tools that can provide quick, simple treatments to prevent infection while providing coverage. By reducing the occurrence of infection, the recovery is shortened, leading to an overall improvement in quality of life. Cite this article: Bone Joint Res 2021;10(2):149-155.

Negative pressure wound therapy for skin necrosis prevention after snakebite in the emergency department: A retrospective cohort study

This retrospective cohort study aimed to compare the effectiveness of conventional treatment and ultra-early application of negative pressure wound therapy (NPWT) in patients with snakebites.Patients who visited the emergency department within 24 hours after a snakebite were assigned to the non- NPWT or NPWT group. Swelling resolution time and rates of necrosis, infection, and operations were compared between the 2 groups. The Stony Brook Scar Evaluation Scale was used to measure short- and long-term wound healing results.Among the included 61 patients, the swelling resolution time was significantly shorter in the NPWT group than in non- NPWT group (P = .010). The NPWT group showed lower necrosis (4.3% versus 36.8%; P = .003) and infection (13.2% and 4.3%; P = .258) rates than the non- NPWT group. The median Stony Brook Scar Evaluation Scale scores were higher in the NPWT group than in the non- NPWT group (P< .001).These findings suggest that ultra-early application of NPWT reduces edema, promotes wound healing, and prevents necrosis in patients with snakebites.

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.

Randomized clinical trial of negative pressure wound therapy as an adjunctive treatment for small-area thermal burns in children

Background

The efficacy of negative pressure wound therapy (NPWT) in the acute management of burns remains unclear. The purpose of this trial was to compare standard Acticoat™ and Mepitel™ dressings with combined Acticoat™, Mepitel™ and continuous NPWT to determine the effect of adjunctive NPWT on re‐epithelialization in paediatric burns.

Methods

This two‐arm, single‐centre RCT recruited children with acute thermal burns covering less than 5 per cent of their total body surface area. The primary outcome was time to re‐epithelialization. Blinded assessments were performed using photographs captured every 3–5 days until discharge. Secondary measures included pain, itch, grafting, perfusion and scar management referrals.

Results

Some 114 patients were randomized. Median time to re‐epithelialization was 8 (i.q.r. 7–11) days in the NPWT group and 10 (8–14) days in the control group. In a multivariable model, NPWT decreased the expected time to wound closure by 22 (95 per cent c.i. 7 to 34) per cent (P = 0·005). The risk of referral to scar management was reduced by 60 (18 to 81) per cent (P = 0·013). Four participants in the control group and one in the NPWT group underwent grafting. There were no statistically significant differences between groups in pain, itch or laser Doppler measures of perfusion. Adverse events were rare and minor, although NPWT carried a moderate treatment burden, with ten patients discontinuing early.

Conclusion

Adjunctive NPWT hastened re‐epithelialization in small‐area burn injuries in children, but had a greater treatment burden than standard dressings alone. Registration number: ACTRN12618000256279 ( http://ANZCTR.org.au).

Negative-pressure wound therapy compared with standard dressings following surgical treatment of major trauma to the lower limb: the WHiST RCT

BACKGROUND

Major trauma is the leading cause of death in people aged < 45 years. Patients with major trauma usually have lower-limb fractures. Surgery to fix the fractures is complicated and the risk of infection may be as high as 27%. The type of dressing applied after surgery could potentially reduce the risk of infection.

OBJECTIVES

To assess the deep surgical site infection rate, disability, quality of life, patient assessment of the surgical scar and resource use in patients with surgical incisions associated with fractures following major trauma to the lower limbs treated with incisional negative-pressure wound therapy versus standard dressings.

DESIGN

A pragmatic, multicentre, randomised controlled trial.

SETTING

Twenty-four specialist trauma hospitals representing the UK Major Trauma Network.

PARTICIPANTS

A total of 1548 adult patients were randomised from September 2016 to April 2018. Exclusion criteria included presentation > 72 hours after injury and inability to complete questionnaires.

INTERVENTIONS

Incisional negative-pressure wound therapy (n = 785), in which a non-adherent absorbent dressing covered with a semipermeable membrane is connected to a pump to create a partial vacuum over the wound, versus standard dressings not involving negative pressure (n = 763). Trial participants and the treating surgeon could not be blinded to treatment allocation.

MAIN OUTCOME MEASURES

Deep surgical site infection at 30 days was the primary outcome measure. Secondary outcomes were deep infection at 90 days, the results of the Disability Rating Index, health-related quality of life, the results of the Patient and Observer Scar Assessment Scale and resource use collected at 3 and 6 months post surgery.

RESULTS

A total of 98% of participants provided primary outcome data. There was no evidence of a difference in the rate of deep surgical site infection at 30 days. The infection rate was 6.7% (50/749) in the standard dressing group and 5.8% (45/770) in the incisional negative-pressure wound therapy group (intention-to-treat odds ratio 0.87; 95% confidence interval 0.57 to 1.33; p = 0.52). There was no difference in the deep surgical site infection rate at 90 days: 13.2% in the standard dressing group and 11.4% in the incisional negative-pressure wound therapy group (odds ratio 0.84, 95% confidence interval 0.59 to 1.19; p = 0.32). There was no difference between the two groups in disability, quality of life or scar appearance at 3 or 6 months. Incisional negative-pressure wound therapy did not reduce the cost of treatment and was associated with a low probability of cost-effectiveness.

LIMITATIONS

Owing to the emergency nature of the surgery, we anticipated that some patients who were randomised would subsequently be unable or unwilling to participate. However, the majority of the patients (85%) agreed to participate. Therefore, participants were representative of the population with lower-limb fractures associated with major trauma.

CONCLUSIONS

The findings of this study do not support the use of negative-pressure wound therapy in patients having surgery for major trauma to the lower limbs.

FUTURE WORK

Our work suggests that the use of incisional negative-pressure wound therapy dressings in other at-risk surgical wounds requires further investigation. Future research may also investigate different approaches to reduce postoperative infections, for example the use of topical antibiotic preparations in surgical wounds and the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN12702354 and UK Clinical Research Network Portfolio ID20416.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 38. See the NIHR Journals Library for further project information.

Preconditioning with Foam-mediated External Suction on Flap Microvasculature and Perfusion in a Rodent Model

Foam-mediated external suction (FMES) has previously shown to improve tissue microcirculation. We hypothesized that preconditioning fasciocutaneous perforator flaps with FMES would augment perfusion and demonstrate greater capillary recruitment.

Prophylactic negative pressure wound therapy for closed laparotomy wounds: a systematic review and meta-analysis of randomised controlled trials

Surgical site infections are a common source of post-operative morbidity and contribute significantly to healthcare costs. Patients undergoing emergency laparotomy and/or bowel surgery are particularly at risk. Prophylactic negative pressure wound therapy (NPWT) has been shown to reduce wound infection. However, to date, there has been a lack of consensus around its use for closed laparotomy wounds. We conducted a systematic review of randomised controlled trials comparing the use of prophylactic negative pressure wound therapy with standard dressings for closed laparotomy incisions. The primary outcome was incidence of incisional surgical site infection (SSI) at 30 days post-operatively. Secondary outcomes included superficial and deep SSI, skin dehiscence, fascial dehiscence and length of stay. A total of 2182 publications were identified, of which, following review of titles, abstracts and full texts, five studies met the criteria for inclusion. Across these studies, 467 patients were randomised to NPWT and 464 to standard dressings. Overall SSI rate was 18.6% (n = 87/467) versus 23.9% (n = 111/464) in the NPWT and standard dressing groups, respectively (Odds ratio 0.71, 95% CI 0.52–0.99, p = 0.04*). Deep SSI incidence was the same in both groups (2.6%). Both skin dehiscence and fascial dehiscence were slightly higher in the standard dressing group ((4.2%, n = 11/263 versus 3.1% (n = 8/261) and (0.9% (n = 3/324) versus 0.6% (n = 2/323)), respectively. This study observed that NPWT reduces the overall SSI for closed laparotomy wounds. It supports data recommending the use of prophylactic NPWT dressings, especially in high-risk patients in both emergency and elective circumstances.

Negative pressure wound therapy for surgical wounds healing by primary closure

BACKGROUND

Indications for the use of negative pressure wound therapy (NPWT) are broad and include prophylaxis for surgical site infections (SSIs). Existing evidence for the effectiveness of NPWT on postoperative wounds healing by primary closure remains uncertain.

OBJECTIVES

To assess the effects of NPWT for preventing SSI in wounds healing through primary closure, and to assess the cost-effectiveness of NPWT in wounds healing through primary closure.

SEARCH METHODS

In June 2019, 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 and references of included studies, systematic reviews and health technology reports. There were no restrictions on language, publication date or study setting.

SELECTION CRITERIA

We included trials if they allocated participants to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with another type of NPWT.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trials using predetermined inclusion criteria. We carried out data extraction, assessment using the Cochrane 'Risk of bias' tool, and quality assessment according to Grading of Recommendations, Assessment, Development and Evaluations methodology.

MAIN RESULTS

In this third update, we added 15 new randomised controlled trials (RCTs) and three new economic studies, resulting in a total of 44 RCTs (7447 included participants) and five economic studies. Studies evaluated NPWT in the context of a wide range of surgeries including orthopaedic, obstetric, vascular and general procedures. Economic studies assessed NPWT in orthopaedic, obstetric and general surgical settings. All studies compared NPWT with standard dressings. Most studies had unclear or high risk of bias for at least one key domain. Primary outcomes Four studies (2107 participants) reported mortality. There is low-certainty evidence (downgraded twice for imprecision) showing no clear difference in the risk of death after surgery for people treated with NPWT (2.3%) compared with standard dressings (2.7%) (risk ratio (RR) 0.86; 95% confidence interval (CI) 0.50 to 1.47; I² = 0%). Thirty-nine studies reported SSI; 31 of these (6204 participants), were included in meta-analysis. There is moderate-certainty evidence (downgraded once for risk of bias) that NPWT probably results in fewer SSI (8.8% of participants) than treatment with standard dressings (13.0% of participants) after surgery; RR 0.66 (95% CI 0.55 to 0.80 ; I² = 23%). Eighteen studies reported dehiscence; 14 of these (3809 participants) were included in meta-analysis. There is low-certainty evidence (downgraded once for risk of bias and once for imprecision) showing no clear difference in the risk of dehiscence after surgery for NPWT (5.3% of participants) compared with standard dressings (6.2% of participants) (RR 0.88, 95% CI 0.69 to 1.13; I² = 0%). Secondary outcomes There is low-certainty evidence showing no clear difference between NPWT and standard treatment for the outcomes of reoperation and incidence of seroma. For reoperation, the RR was 1.04 (95% CI 0.78 to 1.41; I² = 13%; 12 trials; 3523 participants); for seroma, the RR was 0.72 (95% CI 0.50 to 1.05; I² = 0%; seven trials; 729 participants). The effect of NPWT on occurrence of haematoma or skin blisters is uncertain (very low-certainty evidence); for haematoma, the RR was 0.67 (95% CI 0.28 to 1.59; I² = 0%; nine trials; 1202 participants) and for blisters the RR was 2.64 (95% CI 0.65 to 10.68; I² = 69%; seven trials; 796 participants). The overall effect of NPWT on pain is uncertain (very low-certainty evidence from seven trials (2218 participants) which reported disparate measures of pain); but moderate-certainty evidence suggests there is probably little difference between the groups in pain after three or six months following surgery for lower limb fracture (one trial, 1549 participants). There is also moderate-certainty evidence for women undergoing caesarean sections (one trial, 876 participants) and people having surgery for lower limb fractures (one trial, 1549 participants) that there is probably little difference in quality of life scores at 30 days or 3 or 6 months, respectively. Cost-effectiveness Five economic studies, based wholly or partially on trials included in our review, assessed the cost-effectiveness of NPWT compared with standard care. They considered NPWT in four indications: caesarean sections in obese women; surgery for lower limb fracture; knee/hip arthroplasty and coronary artery bypass graft surgery. They calculated quality-adjusted life-years for treatment groups and produced estimates of the treatments' relative cost-effectiveness. The reporting quality was good but the grade of the evidence varied from moderate to very low. There is moderate-certainty evidence that NPWT in surgery for lower limb fracture was not cost-effective at any threshold of willingness-to-pay and that NPWT is probably cost-effective in obese women undergoing caesarean section. Other studies found low or very low-certainty evidence indicating that NPWT may be cost-effective for the indications assessed.

AUTHORS' CONCLUSIONS

People experiencing primary wound closure of their surgical wound and treated prophylactically with NPWT following surgery probably experience fewer SSI than people treated with standard dressings (moderate-certainty evidence). There is no clear difference in number of deaths or wound dehiscence between people treated with NPWT and standard dressings (low-certainty evidence). There are also no clear differences in secondary outcomes where all evidence was low or very low-certainty. In caesarean section in obese women and surgery for lower limb fracture, there is probably little difference in quality of life scores (moderate-certainty evidence). Most evidence on pain is very low-certainty, but there is probably no difference in pain between NPWT and standard dressings after surgery for lower limb fracture (moderate-certainty evidence). Assessments of cost-effectiveness of NPWT produced differing results in different indications. There is a large number of ongoing studies, the results of which may change the findings of this review. Decisions about use of NPWT should take into account surgical indication and setting and consider evidence for all outcomes.

Potential molecular mechanisms of negative pressure in promoting wound healing

Negative pressure wound therapy (NPWT) has been widely used in various lesions. This study aimed to explore the biological effects of negative pressure on the polymorphonuclear neutrophils (PMNs), macrophages, and epidermal keratinocyte cells involved in wound healing. PMNs differentiated from HL-60, macrophages were derived from THP-1 monocytes, and keratinocytes were cultured in vitro, and they were treated with 0, -0.03 mp, and -0.05 mp, respectively. Cell ultrastructure; viability; apoptosis; and protein factors such as tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), interleukin-17 (IL-17), and cell division cycle 42 (Cdc42) were determined by transmission electron microscopy (TEM), CCK8, flow cytometry (FCM), ELISA, and simple Western assays, respectively. After negative pressure stimulation, the cell ultrastructure of PMNs and macrophages cells was presented with a marked increase of lysosomes and a relative decrease of mitochondria. In addition, the cell viability was enhanced in PMNs and macrophages in a pressure-dependent manner and apoptosis ratios were significantly reduced in PMNs and macrophages. In addition, under -0.05 negative pressure, IFN-γ and IL-17 were significantly increased in PMNs or macrophages. Moreover, increased EGF and EGFR and Cdc42 levels in keratinocytes induced by the -0.05 mpa were detected, indicating that the migration chemotaxis of keratinocyte cells was enhanced. Negative pressure might promote cell proliferation, accelerate inflammatory responses, and promote epithelialisation during wound healing by increasing IFN-γ, IL-17, Cdc42, EGF, and EGFR in PMNs, macrophages, or keratinocytes under different negative pressures.

Effect of Combining Low Temperature Plasma, Negative Pressure Wound Therapy, and Bone Marrow Mesenchymal Stem Cells on an Acute Skin Wound Healing Mouse Model

Low-temperature plasma (LTP; 3 min/day), negative pressure wound therapy (NPWT; 4 h/day), and bone marrow mesenchymal stem cells (MSCs; 1×106 cells/day) were used as mono- and combination therapy in an acute excisional skin wound-healing ICR mouse model. These therapies have been beneficial in treating wounds. We investigated the effectiveness of monotherapy with LTP, NPWT, and MSC and combination therapy with LTP + MSC, LTP + NPWT, NPWT + MSC, and LTP + NPWT + MSC on skin wounds in mice for seven consecutive days. Gene expression, protein expression, and epithelial thickness were analyzed using real time polymerase chain reaction (RT-qPCR), western blotting, and hematoxylin and eosin staining (H&E), respectively. Wound closure was also evaluated. Wound closure was significantly accelerated in monotherapy groups, whereas more accelerated in combination therapy groups. Tumor necrosis factor-α (TNF-α) expression was increased in the LTP monotherapy group but decreased in the NPWT, MSC, and combination therapy groups. Expressions of vascular endothelial growth factor (VEGF), α-smooth muscle actin (α-SMA), and type I collagen were increased in the combination therapy groups. Re-epithelialization was also considerably accelerated in combination therapy groups. Our findings suggest that combination therapy with LPT, NPWT, and MSC exert a synergistic effect on wound healing, representing a promising strategy for the treatment of acute wounds.

Negative pressure wound therapy for surgical wounds healing by primary closure

BACKGROUND

Indications for the use of negative pressure wound therapy (NPWT) are broad and include prophylaxis for surgical site infections (SSIs). Existing evidence for the effectiveness of NPWT on postoperative wounds healing by primary closure remains uncertain.

OBJECTIVES

To assess the effects of NPWT for preventing SSI in wounds healing through primary closure, and to assess the cost-effectiveness of NPWT in wounds healing through primary closure.

SEARCH METHODS

In June 2019, 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 and references of included studies, systematic reviews and health technology reports. There were no restrictions on language, publication date or study setting.

SELECTION CRITERIA

We included trials if they allocated participants to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with another type of NPWT.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trials using predetermined inclusion criteria. We carried out data extraction, assessment using the Cochrane 'Risk of bias' tool, and quality assessment according to Grading of Recommendations, Assessment, Development and Evaluations methodology.

MAIN RESULTS

In this third update, we added 15 new randomised controlled trials (RCTs) and three new economic studies, resulting in a total of 44 RCTs (7447 included participants) and five economic studies. Studies evaluated NPWT in the context of a wide range of surgeries including orthopaedic, obstetric, vascular and general procedures. Economic studies assessed NPWT in orthopaedic, obstetric and general surgical settings. All studies compared NPWT with standard dressings. Most studies had unclear or high risk of bias for at least one key domain. Primary outcomes Four studies (2107 participants) reported mortality. There is low-certainty evidence (downgraded twice for imprecision) showing no clear difference in the risk of death after surgery for people treated with NPWT (2.3%) compared with standard dressings (2.7%) (risk ratio (RR) 0.86; 95% confidence interval (CI) 0.50 to 1.47; I² = 0%). Thirty-nine studies reported SSI; 31 of these (6204 participants), were included in meta-analysis. There is moderate-certainty evidence (downgraded once for risk of bias) that NPWT probably results in fewer SSI (8.8% of participants) than treatment with standard dressings (13.0% of participants) after surgery; RR 0.66 (95% CI 0.55 to 0.80 ; I² = 23%). Eighteen studies reported dehiscence; 14 of these (3809 participants) were included in meta-analysis. There is low-certainty evidence (downgraded once for risk of bias and once for imprecision) showing no clear difference in the risk of dehiscence after surgery for NPWT (5.3% of participants) compared with standard dressings (6.2% of participants) (RR 0.88, 95% CI 0.69 to 1.13; I² = 0%). Secondary outcomes There is low-certainty evidence showing no clear difference between NPWT and standard treatment for the outcomes of reoperation and incidence of seroma. For reoperation, the RR was 1.04 (95% CI 0.78 to 1.41; I² = 13%; 12 trials; 3523 participants); for seroma, the RR was 0.72 (95% CI 0.50 to 1.05; I² = 0%; seven trials; 729 participants). The effect of NPWT on occurrence of haematoma or skin blisters is uncertain (very low-certainty evidence); for haematoma, the RR was 0.67 (95% CI 0.28 to 1.59; I² = 0%; nine trials; 1202 participants) and for blisters the RR was 2.64 (95% CI 0.65 to 10.68; I² = 69%; seven trials; 796 participants). The overall effect of NPWT on pain is uncertain (very low-certainty evidence from seven trials (2218 participants) which reported disparate measures of pain); but moderate-certainty evidence suggests there is probably little difference between the groups in pain after three or six months following surgery for lower limb fracture (one trial, 1549 participants). There is also moderate-certainty evidence for women undergoing caesarean sections (one trial, 876 participants) and people having surgery for lower limb fractures (one trial, 1549 participants) that there is probably little difference in quality of life scores at 30 days or 3 or 6 months, respectively. Cost-effectiveness Five economic studies, based wholly or partially on trials included in our review, assessed the cost-effectiveness of NPWT compared with standard care. They considered NPWT in four indications: caesarean sections in obese women; surgery for lower limb fracture; knee/hip arthroplasty and coronary artery bypass graft surgery. They calculated quality-adjusted life-years for treatment groups and produced estimates of the treatments' relative cost-effectiveness. The reporting quality was good but the grade of the evidence varied from moderate to very low. There is moderate-certainty evidence that NPWT in surgery for lower limb fracture was not cost-effective at any threshold of willingness-to-pay and that NPWT is probably cost-effective in obese women undergoing caesarean section. Other studies found low or very low-certainty evidence indicating that NPWT may be cost-effective for the indications assessed.

AUTHORS' CONCLUSIONS

People experiencing primary wound closure of their surgical wound and treated prophylactically with NPWT following surgery probably experience fewer SSI than people treated with standard dressings (moderate-certainty evidence). There is no clear difference in number of deaths or wound dehiscence between people treated with NPWT and standard dressings (low-certainty evidence). There are also no clear differences in secondary outcomes where all evidence was low or very low-certainty. In caesarean section in obese women and surgery for lower limb fracture, there is probably little difference in quality of life scores (moderate-certainty evidence). Most evidence on pain is very low-certainty, but there is probably no difference in pain between NPWT and standard dressings after surgery for lower limb fracture (moderate-certainty evidence). Assessments of cost-effectiveness of NPWT produced differing results in different indications. There is a large number of ongoing studies, the results of which may change the findings of this review. Decisions about use of NPWT should take into account surgical indication and setting and consider evidence for all outcomes.

[Effect of decellularized adipose tissue combined with vacuum sealing drainage on wound inflammation in pigs]

Objective

To preliminary explore the effect of decellularized adipose tissue (DAT) combined with vacuum sealing drainage (VSD) on wound inflammation in pigs.

Methods

The DAT was prepared through the process of freeze-thaw, enzymatic digestion, organic solvent extraction, and vacuum freeze-drying. The appearance of DAT was observed before and after freeze-drying. HE staining was used to observe its structure and acellular effect. Eighteen male Bama minipigs were recruited, and four dorsal skin soft tissue wounds in diameter of 4 cm were made on each pig and randomly divided into 4 groups for different treatments. The wounds were treated with DAT combined with VSD in DAT/VSD group, DAT in DAT group, VSD in VSD group, and sterile gauze dressing in control group. HE staining was performed at 3, 7, 10, and 14 days after treatment. Moreover, the expressions of inflammatory factors [interleukin 1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)], as well as the phenotypes of M1 and M2 macrophage phenotypic markers [inducible nitric oxide synthase (iNOS) and arginase 1 (ARG-1)] were detected by real-time fluorescence quantitative PCR (qRT-PCR). ELISA was used to determine the content of iNOS and ARG-1.

Results

General observation and HE staining showed that DAT obtained in this study had a loose porous structure without cells. The neutrophils of wounds were significantly less in DAT/VSD group than in control group and DAT group ( P<0.05) at 3 days after treatment, and the difference was not significant ( P>0.05) between DAT/VSD group and VSD group. And the neutrophils were significantly less in DAT/VSD group than in other three groups ( P<0.05) at 7, 10, and 14 days. The mRNA expressions of IL-1β, IL-6, TNF-α, and iNOS were significantly lower in DAT/VSD group than in other three groups at 3, 7, 10, and 14 days ( P<0.05), while the mRNA expression of ARG-1 was significantly higher in DAT/VSD group than in other three groups ( P<0.05). ELISA showed that the content of iNOS was significantly lower in DAT/VSD group than in other three groups at 3, 7, 10, and 14 days ( P<0.05), while the content of ARG-1 was significantly higher in DAT/VSD group than in other three groups ( P<0.05).

Conclusion

DAT combined with VSD can significantly reduce inflammatory cell infiltration during wound healing, regulate the expressions of inflammatory factors and macrophage phenotype, and the effect is better than single use of each and conventional dressing change.

Negative Pressure Wound Therapy Reduces Wound Breakdown and Implant Loss in Prepectoral Breast Reconstruction

Background:

Single-use negative pressure wound therapy (NPWT) has been shown to encourage wound healing. It is often used when patient factors impair wound healing, or in more complex wounds, such as in implant-based breast reconstruction. We report the findings of a prospective cohort study comparing the use of NPWT with standard dressings in prepectoral breast reconstruction.

Methods:

A prospective database of implant-based reconstruction from a single institution was mined to identify patients who underwent prepectoral reconstruction. Patient demographics, operative data, surgical complications, and 90-day outcomes were compared between patients who had NPWT and those who had standard dressings.

Results:

Prepectoral implant-based breast reconstruction was performed on 307 breasts. NPWT dressings were used in 126 cases, with standard dressings used in 181 cases. Wound breakdown occurred in 10 cases after standard dressings versus 1 where NPWT was utilized. Of the standard dressing cases, only 3 implants were salvaged, while 7 cases led to implant loss. The 1 case of wound breakdown in the NPWT cohort settled with conservative measures. The cost of a reconstructive failure was £14,902, and the use of NPWT resulted in a cost savings of £426 per patient.

Conclusions:

The utilization of single-use NPWT reduces the rate of wound breakdown and implant loss in prepectoral implant-based reconstruction. In addition to the significant clinical benefits, this approach is cost-saving compared with standard dressings. These data suggest that prepectoral implant reconstruction should be considered as an indication for the use of NPWT.

Effect of Incisional Negative Pressure Wound Therapy vs Standard Wound Dressing on Deep Surgical Site Infection After Surgery for Lower Limb Fractures Associated With Major Trauma: The WHIST Randomized Clinical Trial

IMPORTANCE

Following surgery to treat major trauma-related fractures, deep wound infection rates are high. It is not known if negative pressure wound therapy can reduce infection rates in this setting.

OBJECTIVE

To assess outcomes in patients who have incisions resulting from surgery for lower limb fractures related to major trauma and were treated with either incisional negative pressure wound therapy or standard wound dressing.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial conducted at 24 trauma hospitals representing the UK Major Trauma Network that included 1548 patients aged 16 years or older who underwent surgery for a lower limb fracture caused by major trauma from July 7, 2016, through April 17, 2018, with follow-up to December 11, 2018.

INTERVENTIONS

Incisional negative pressure wound therapy (n = 785), which involved a specialized dressing used to create negative pressure over the wound, vs standard wound dressing not involving negative pressure (n = 763).

MAIN OUTCOMES AND MEASURES

The primary outcome measure was deep surgical site infection at 30 days diagnosed according to the criteria from the US Centers for Disease Control and Prevention. A preplanned secondary analysis of the primary outcome was performed at 90 days. The secondary outcomes were patient-reported disability (Disability Rating Index), health-related quality of life (EuroQol 5-level EQ-5D), surgical scar assessment (Patient and Observer Scar Assessment Scale), and chronic pain (Douleur Neuropathique Questionnaire) at 3 and 6 months, as well as other local wound healing complications at 30 days.

RESULTS

Among 1548 participants who were randomized (mean [SD] age, 49.8 [20.3] years; 561 [36%] were aged ≤40 years; 583 [38%] women; and 881 [57%] had multiple injuries), 1519 (98%) had data available for the primary outcome. At 30 days, deep surgical site infection occurred in 5.84% (45 of 770 patients) of the incisional negative pressure wound therapy group and in 6.68% (50 of 749 patients) of the standard wound dressing group (odds ratio, 0.87 [95% CI, 0.57 to 1.33]; absolute risk difference, -0.77% [95% CI, -3.19% to 1.66%]; P = .52). There was no significant difference in the deep surgical site infection rate at 90 days (11.4% [72 of 629 patients] in the incisional negative pressure wound therapy group vs 13.2% [78 of 590 patients] in the standard wound dressing group; odds ratio, 0.84 [95% CI, 0.59 to 1.19]; absolute risk difference, -1.76% [95% CI, -5.41% to 1.90%]; P = .32). For the 5 prespecified secondary outcomes reported, there were no significant differences at any time point.

CONCLUSIONS AND RELEVANCE

Among patients who underwent surgery for major trauma-related lower limb fractures, use of incisional negative pressure wound therapy, compared with standard wound dressing, resulted in no significant difference in the rate of deep surgical site infection. The findings do not support the use of incisional negative pressure wound therapy in this setting, although the event rate at 30 days was lower than expected.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN12702354.

Conservative treatment for urinary fistula following ileal conduit urinary diversion: a simple method

Background

The presence of urinary fistula after ileal conduit urinary diversion is a challenging complication, and this study investigated the role of the intra-conduit negative pressure system (NPS) in the presence of urinary fistula following ileal conduit (IC) urinary diversion as a conservative treatment.

Methods

Using the intra-conduit NPS, a minor drainage tube was placed within a silicon tube to suck urine from the conduit with consistent negative pressure. Patients with urinary fistula following IC from August 2012 to July 2017 were recorded, and the clinical characteristics and outcome were retrospectively analyzed.

Results

The intra-conduit NPS was used as a primarily conservative treatment for 13 patients who suffered from urinary fistula and presented with a large amount of abdominal/pelvic drainage without other significant morbidities. The median age was 60 years old (42–74 years), and 7patients were male. The median duration between the IC operation and the presence of urinary fistula was 15 days (2–28 days), and elevated creatinine levels were detected in the abdominal/pelvic drainage with a median level of 2114 μmol/L (636–388 μmol/L). A significant decrease in abdominal/pelvic drainage was identified in 12 patients. The median time that the NPS was used was 9 days (7–11 days). The other patient did not show any improvements after 2 days of observation and then underwent open surgery. With ureteral stenting, 2 abdominal drainage tubes and the intra-conduit NPS were placed during operation, no urine leakage was observed in the abdominal/pelvic field, and the patient was cured in 9 days. With a median follow-up of 22 months, no fistula recurrence or hydronephrosis was detected.

Conclusion

The intra-conduit negative pressure system is a feasible and promising way to cure urinary fistula following ileal conduit urinary diversion. Because this procedure is a mini-invasive and simple approach, it might represent an alternative in selected patients.

Wound-Healing Following Negative-Pressure Wound Therapy with Use of a Locally Developed AquaVac System as Compared with the Vacuum-Assisted Closure (VAC) System

BACKGROUND

Negative-pressure wound therapy (NPWT) gained widespread clinical use after its introduction in the 1990s because of its many beneficial effects on the wound environment. However, high treatment costs have limited its use in third-world countries. The present study compares a low-cost, locally developed NPWT system with a commercially available system in terms of efficacy, reliability, ease of application, and safety.

METHODS

This prospective, randomized controlled trial involved 36 patients who were managed with NPWT with either a low-cost, locally developed system (AquaVac) or a commercially available Vacuum-Assisted Closure Advanced Therapy System (VAC ATS; KCI). The low-cost NPWT system described consists of a converted aquarium pump as a reusable vacuum source and a dressing system that can be found in the hospital supply room: food plastic wrap as an occlusive drape, surgical gauze as wound filler, nasogastric tubes as tubing, and used intravenous (IV) bottles as effluent canisters. The purpose of the study was to compare the 2 systems in terms of (1) time to apply the dressing, (2) exudate levels, (3) amount of granulation tissue, (4) wound size reduction, (5) average cost of treatment, (6) visual analog scale (VAS) pain scores, and (7) complications.

RESULTS

The experimental low-cost system had a small but statistically insignificant advantage over the commercially available system in terms of application time, pain during dressing changes, and wound contraction percentage. The 2 systems were comparable in terms of the amount of exudate, granulation tissue coverage, and VAS scores during the course of treatment. No wound or periwound complications were observed. The systems were significantly different in terms of cost, with the AquaVac system being 7 times less expensive than the VAC ATS system ($63.75 compared with $491.38 USD).

CONCLUSIONS

The low-cost AquaVac system was shown to be comparable with the commercial VAC ATS system, suggesting that it is an effective and safe alternative method for NPWT in resource-challenged settings.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Negative-pressure sternal wound closure with interrupted subcuticular suturing and a subcutaneous drain tube reduces the incidence of poststernotomy wound infection after coronary artery bypass grafting surgery

PURPOSES

To retrospectively evaluate the effect of negative-pressure sternal wound closure (NPSWC) with a subcutaneous closed drain tube on the sternal surgical site infection (SSI) incidence.

METHODS

After propensity score matching of 231 patients undergoing coronary artery bypass grafting (CABG), we compared 104 pairs in the NPSWC and historical control groups. In the molecular analysis, the interleukin-6 (IL-6), basic fibroblast growth factor (b-FGF), and transforming growth factor β1 (TGF-β1) levels in the wound fluid were measured using two different reservoir types at postoperative days 2 and 7.

RESULTS

NPSWC significantly reduced the SSI incidence from 10.6 to 2.9%. No mediastinitis occurred in the NPSWC group. A multivariate logistic regression analysis identified female sex (p = 0.0040) and no NPSWC (p = 0.0084) as significant risk factors for sternal SSI development. The Negative-pressure value was 49.4 ± 4.1 and 115.5 ± 15.2 mmHg in the standard-type (SSR) and bulb-type suction reservoirs (BSR), respectively. Given that growth factors were affected by the difference in negative pressure, the IL-6, b-FGF, and TGF-β1 levels were significantly higher in the BSR than in the SSR.

CONCLUSIONS

NPSWC using a subcutaneous closed drain tube was effective in preventing sternal SSI after CABG and may accelerate wound healing even when both internal thoracic arteries are harvested.

CLINICAL REGISTRATION NUMBER

University Hospital Medical Information Network Clinical Trials Registry, registration number: UMIN000037060.

Systematic review of negative pressure wound therapy for head and neck wounds with fistulas: Outcomes and complications

Fistula formation in head and neck wounds is considered one of the most challenging complications that a head and neck reconstructive surgeon may encounter. The current mainstay of treatment is aggressive surgical debridement followed by vascularised soft tissue coverage. Negative pressure wound therapy (NPWT) has been successfully used for the closure of complicated wounds for decades. This study analysed the outcomes and complications of NPWT in the management of head and neck wounds with fistulas. A systematic search of studies published between January 1966 and September 2019 was conducted using the PubMed, MEDLINE, EMBASE, and SCOPUS databases and using the following key words: "negative pressure wound therapy," "head and neck," and "fistula." We included human studies with abstract and full text available. Analysed endpoints were rate of fistula closure, follow-up duration, and complications if present. Nine retrospective case series (Level IV evidence) that collectively included 122 head and neck wounds with orocutaneous fistulas, pharyngocutaneous fistulas, and salivary contamination were examined. The number of patients included in each study ranged from 5 to 64. The mode of NPWT varied among the included studies, with most adopting a continuous pressure of -125 mm Hg. Mean durations of NPWT ranged from 3.7 to 23 days, and the reported fistula closure rate ranged from 78% to 100%. To achieve complete wound healing, six studies used additional procedures after stopping NPWT, including conventional wound dressings and vascularised tissue transfer. Information regarding follow up was provided in only three of the nine studies, where patients were followed for 5, 10, and 18 months. No serious adverse events were reported. NPWT for head and neck wounds with fistulas may be considered a safe treatment method that yields beneficial outcomes with a low risk of complications. The current data originated mainly from studies with low levels of evidence characterised by heterogeneity. Therefore, definitive recommendations based on these data cannot be offered. Additional high-quality trials are warranted to corroborate the findings of this systematic review.

Prophylactic negative wound therapy in laparotomy wounds (PROPEL trial): randomized controlled trial

BACKGROUND

Superficial surgical site infections are a common post-operative complication. They also place a considerable financial burden on healthcare. The use of prophylactic negative pressure wound therapy has been advocated to reduce wound infection rates. However, there is debate around its routine use. The purpose of this trial is to determine if prophylactic negative pressure wound therapy reduces post-operative wound complications in patients undergoing laparotomy.

METHODS/DESIGN

This multi-centre randomised controlled trial will compare standard surgical dressings (control) to two competing negative pressure wound therapy dressings (Prevena™ and PICO™). All patients will be over 18 years, who are undergoing an emergency or elective laparotomy. It is intended to enrol a total of 271 patients for the trial.

DISCUSSION

The PROPEL trial is a multi-centre randomised controlled trial of patients undergoing laparotomy. The comparison of standard treatment to two commercially available NPWT will help provide consensus on the routine management of laparotomy wounds.

TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov (NCT number NCT03871023).

Effects of Negative Pressure Wound Therapy on Levels of Angiopoetin-2 and Other Selected Circulating Signaling Molecules in Patients with Diabetic Foot Ulcer

BACKGROUND AND AIMS

Diabetic foot ulcers (DFUs) are linked to amputations and premature deaths. Negative pressure wound therapy (NPWT) has been used for DFUs. The mechanism of NPWT's action may be associated with its influence on circulating molecules. We assessed NPWT's effect on the plasma levels of angiopoietin-2 (Ang2), a key regulator of angiogenesis, and its microvesicular receptors (Tie2) as well as the microvesicles (MVs) themselves in DFU patients.

MATERIALS AND METHODS

We included 69 patients with type 2 diabetes mellitus (T2DM) and neuropathic, noninfected DFUs-49 were treated with NPWT and 20 were treated with standard therapy (ST). Assigning patients to the NPWT group was not random but based on DFU characteristics, especially wound area. Ang2 was measured by ELISA in the entire group, while in a subgroup of 19 individuals on NPWT and 10 on ST, flow cytometry was used to measure Tie2+ and the corresponding isotype control (Iso+) and annexin V (AnnV+) as well as total MVs. Measurements were performed at the beginning and after 8 ± 1 days of therapy.

RESULTS

Treatment groups were similar for basic characteristics but differed by their median DFU areas (10.3 (4.2-18.9) vs. 1.3 (0.9-3.4) cm2, p = 0.0001). At day 0, no difference was observed in Ang2 levels, total MVs, MV Tie+, and MV AnnV+ between the groups. Ang2 decreased after 8 days in the NPWT group, unlike in the ST group (3.54 (2.40-5.40) vs. 3.32 (2.33-4.61), p = 0.02, and 3.19 ± 1.11 vs. 3.19 ± 1.29 ng/mL, p = 0.98, respectively). No other parameters were identified that may have been influenced by the NPWT treatment.

CONCLUSION

NPWT in T2DM patients with neuropathic, noninfected DFU seems to lead to reduction of the Ang2 level. Influencing the level of Ang2 may constitute one of NPWT-related mechanisms to accelerate wound healing.

Comparison between two different protocols of negative pressure therapy for healing of chronic ulcers

BACKGROUND

Negative pressure therapy plays an important role in the healing process of different types of wounds.

AIM OF THE STUDY

this study aimed to compare between modified and traditional method of vacuum wound closure for chronic wounds.

SUBJECTS

Thirty participants with chronic ulcers completed the study, their ages ranged from 47 to 65 years, from Benha city, divided randomly into two groups, it was carried out from December 2017 to March 2019.

METHODS

The first group treated by the traditional method of vacuum assisted wound closure for 8 weeks; dressing was changed 3 times weekly, at 125 mmHg. The mode of 2 min off and 5 min on was used. The second group treated by the modified method by switching off the device at the fifth week and applying traditional dressing for one week then ended by three weeks of vacuum wound closure. Assessment was performed before and after the study. Student t-test was used for analysis.

RESULT

Paired t-test showed a significant improvement in wound surface area as well as volume for pre and post treatment in each group (p < 0.05). On the other hand independent t-test revealed a non-significant difference between the two groups pre as well as post treatment (p > 0.05).

CONCLUSION

There is no significant difference between the two programs on healing of chronic ulcers.

CLINICAL TRIAL REGISTRATION NO

NCT03701152 - at Clinicaltrials.gov.

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.

Clinical parameters and outcomes of necrotizing soft tissue infections secondary to gastrointestinal fistulas

Background

Necrotizing soft tissue infections (NSTIs) is severe surgical infections which can occur following trauma or abdominal surgery. NSTIs secondary to gastrointestinal (GI) fistula is a rare but severe complication.

Methods

A retrospective cohort study was performed on all subjects presenting with GI fistulas associated NSTIs were included. Clinical characteristics, microbiological profile, operations performed, and outcomes of patients were analyzed.

Results

Between 2014 and 2017, 39 patients were finally enrolled. The mean age were 46.9 years and male were the dominant. For the etiology of fistula, 25 (64.1%) of the patients was due to trauma. Overall, in-hospital death occurred in 15 (38.5%) patients. Microbiologic findings were obtained from 31 patients and Klebsiella pneumoniae was the most common species (41.0%). Eight patients were treated with an open abdomen; negative pressure wound therapy was used in 33 patients and only 2 patients received hyperbaric oxygen therapy. Younger age and delayed abdominal wall reconstruction repair were more common in trauma than in non-trauma. Non-survivors had higher APACHE II score, less source control< 48 h and lower platelet count on admission than survivors. Multiple organ dysfunction syndrome, multidrug-resistant organisms and source control failure were the main cause of in-hospital mortality.

Conclusions

Trauma is the main cause of GI fistulas associated NSTIs. Sepsis continues to be the most important factor related to mortality. Our data may assist providing enlightenment for quality improvement in these special populations.

Preemptive endoluminal vacuum therapy to reduce anastomotic leakage after esophagectomy: a game-changing approach?

Endoluminal vacuum therapy (EVT) is an accepted treatment for anastomotic leakage (AL) after esophagectomy. A novel concept is to use this technology in a preemptive setting, with the aim to reduce the AL rate and postoperative morbidity. Preemptive EVT (pEVT) was performed intraoperatively in 19 consecutive patients undergoing minimally invasive esophagectomy, immediately after completion of esophagogastrostomy. Twelve patients (63%) were high-risk cases with severe comorbidity. The EVT device was removed routinely three to six (median 5) days after esophagectomy. The endpoints of this study were AL rate and postoperative morbidity. There were 20 anastomoses at risk in 19 patients. One patient (5.3%) experienced major morbidity (Clavien-Dindo grade IIIb) unrelated to anastomotic healing. He underwent open reanastomosis at postoperative day 12 with pEVT for redundancy of the gastric tube and failure of transition to oral diet. Mortality after 30 days was 0% and anastomotic healing was uneventful in 19/20 anastomoses (95%). One minor contained AL healed after a second course of EVT. Except early proximal dislodgement in one patient, there were no adverse events attributable to pEVT. The median comprehensive complication index 30 days after surgery was 20.9 (IQR 0-26.2). PEVT appears to be a safe procedure that may have the potential to improve surgical outcome in patients undergoing esophagectomy.

Sepsis in Acute Mediastinitis - A Severe Complication after Oesophageal Perforations. A Review of the Literature

BACKGROUND

Despite recent advancements in antibiotic therapy and the progress made in critical care and modern diagnostic methods, acute mediastinitis continues to be a severe condition.

DIAGNOSIS AND TREATMENT

Acute mediastinitis can occur in the context of cardio-thoracic surgery, oesophageal perforations and oropharyngeal infections condition. Forty-five percent of oesophageal perforations occurs during simple endoscopy. Spontaneous perforation (Boerhaave syndrome) accounts for 15% of perforations, and twelve percent are due to the ingestion of foreign bodies. Other causes include blind or penetrating trauma, and circa 9% to intraoperative lesions. CT scan is the standard investigation that reveals direct signs of mediastinitis.The oral administration of contrast substances can underscore the level of oesophageal perforation. Conservative treatment is the first-choice treatment and surgical treatment is reserved only for specific situations.The principles of surgical treatment consist of drainage, primary suture, oesophageal exclusion with or without the application of oesophagectomy, endoscopic vacuum wound assisted therapy of the perforation and associated paraoesophageal mediastinal drainage and endoscopic stenting associated with drainage.

CONCLUSIONS

The lowest mortality rate is recorded in patients with perforations diagnosed less than twenty-four hours after the onset of symptoms. Surgical treatment remains the gold standard especially in cases of thoracic and abdominal perforations while further investigations are mandatory before endoscopic stenting is carried out.

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.

Negative Pressure Wound Therapy Versus Closed Suction Irrigation System in the Treatment of Deep Surgical Site Infection After Lumbar Surgery

OBJECTIVE

We compared the efficacy of a closed suction irrigation system (CSIS) and negative pressure wound therapy (NPWT) for deep surgical site infection (SSI) after lumbar surgery with instrumentation.

METHODS

We included 31 patients (NPWT group, n =16; CSIS group, n = 15) with deep SSIs after lumbar surgery with instrumentation from 2007 to 2017. The medical records were reviewed and patient characteristics, laboratory results, infection details, and treatment interventions were recorded. The Japanese Orthopaedic Association score and Oswestry disability index were used to assess pain and functional outcomes preoperatively and 3 and 12 months postoperatively. The cost of SSIs were compared between the NPWT and CSIS groups.

RESULTS

No significant differences were found in the baseline characteristic data between the NPWT and CSIS groups. Implants were retained in all patients in the CSIS group, but required removal from 2 patients with late infections in the NPWT group. The average hospital stay was 36.8 ± 10.5 days and 33.4 ± 18.9 days in the NPWT and CSIS groups, respectively. The cost was greater in the NPWT group than in the CSIS group. Both NPWT and CSIS significantly reduced the Oswestry disability index and improved the Japanese Orthopaedic Association scores, but no significant difference was found between the 2 groups.

CONCLUSIONS

Our results have shown that both NPWT and CSIS are efficient techniques for the management of deep SSI after lumbar surgery with instrumentation. CSIS was more economical and the NPWT system was portable and easier for postoperative nursing care.

Feasibility of a disposable canister-free negative-pressure wound therapy (NPWT) device for treating open wounds in horses

BACKGROUND

Wounds are among the most common medical conditions affecting horses and have a major economic impact on the horse industry. Wound healing in horses is distinct to that documented in other species, and often results in delayed healing and extensive scarring, with compromised functional and aesthetic outcomes. To date, there is no conventional method objectively proven to accelerate healing or to successfully prevent complications associated with second intention healing. Several effects of Negative Pressure Wound Therapy (NPWT) may be particularly useful to the management of wounds in horses. However, cumbersome designs of classic NPWT devices render them unsuitable for equine practice. A new lightweight, portable and disposable unit of NPWT (PICO®), should facilitate the use of this modality by equine practitioners. The aim of this study was to evaluate the feasibility of using this canister-free system to treat experimental open wounds in horses.

RESULTS

No difficulties were encountered with the application or maintenance of the PICO® system during the ex vivo experiment or during the preliminary in vivo experiment conducted on intact skin. All horses readily tolerated the PICO® but difficulties with adhesion and seal prevented the completion of the experimental wound study despite the use of many adjunctive adhesives.

CONCLUSION

The current PICO® dressing design is not suitable to be used as a dressing for open wounds in horses though the device is well tolerated by equine patients. A dressing with a wider adhesive edge, a superior adhesive and a more flexible pad would likely be better adapted to enable its future use in equine practice.

Wound Management: Wounds with Special Challenges

Distal limb wounds in horses heal substantially different than trunk wounds, commonly resulting in exuberant granulation tissue and exposed and sequestered bone. Surgical intervention of severe rectovaginal lacerations in the mare should be delayed until the tissues have heeled and scar tissue has remodeled. Wounds resulting in severe hemorrhage require appropriate emergent fluid therapy and potentially transfusion therapy.

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.

Negative pressure wound therapy in the treatment of diabetic foot ulcers may be mediated through differential gene expression

AIMS

Negative pressure wound therapy (NPWT) has been successfully used as a treatment for diabetic foot ulceration (DFU). Its mechanism of action on the molecular level, however, is not fully understood. We assessed the effect of NPWT on gene expression in patients with type 2 diabetes (T2DM) and DFU.

METHODS

We included two cohorts of patients-individuals treated with either NPWT or standard therapy. The assignment to NWPT was non-randomized and based on wound characteristics. Differential gene expression profiling was performed using Illumina gene expression arrays and R Bioconductor pipelines based on the 'limma' package.

RESULTS

The final cohort encompassed 21 patients treated with NPWT and 8 with standard therapy. The groups were similar in terms of age (69.0 versus 67.5 years) and duration of T2DM (14.5 versus 14.4 years). We identified four genes differentially expressed between the two study arms post-treatment, but not pre-treatment: GFRA2 (GDNF family receptor alpha-2), C1QBP (complement C1q binding protein), RAB35 (member of RAS oncogene family) and SYNJ1 (synaptic inositol 1,4,5-trisphosphate 5-phosphatase 1). Interestingly, all four genes seemed to be functionally involved in wound healing by influencing re-epithelialization and angiogenesis. Subsequently, we utilized co-expression analysis in publicly available RNA-seq data to reveal the molecular functions of GFRA2 and C1QBP, which appeared to be through direct protein-protein interactions.

CONCLUSIONS

We found initial evidence that the NPWT effect on DFUs may be mediated through differential gene expression. A discovery of the specific molecular mechanisms of NPWT is potentially valuable for its clinical application and development of new therapies.

Negative Pressure Wound Therapy for Closed Laparotomy Incisions in General and Colorectal Surgery: A Systematic Review and Meta-analysis

Importance

Surgical site infections (SSIs) are common after laparotomy wounds and are associated with a significant economic burden. The use of negative pressure wound therapy (NPWT) has recently been broadened to closed surgical incisions.

Objective

To evaluate the association of prophylactic NPWT with SSI rates in closed laparotomy incisions performed for general and colorectal surgery in elective and emergency settings.

Data Sources

The PubMed, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar databases were searched without language restrictions for relevant articles from inception until December 2017. The latest search was performed on December 31, 2017. The bibliographies of retrieved studies were further screened for potential additional studies.

Study Selection

Randomized clinical trials and nonrandomized studies were included. Unpublished reports were excluded, as were studies that examined NPWT (or standard nonpressure) dressings only without a comparator group. Studies that evaluated the use of NPWT in open abdominal incisions were also excluded. Disagreement was resolved by discussion, and if the question remained unsettled, the opinion of the senior author was sought. A total of 198 citations were identified, and 189 were excluded.

Data Extraction and Synthesis

This meta-analysis was conducted according to PRISMA guidelines. Data were independently extracted by 2 authors. A random-effects model was used for statistical analysis.

Main Outcomes and Measures

The primary outcome measure was SSI, and secondary outcomes included seroma and wound dehiscence rates. These outcomes were chosen before data collection.

Results

Nine unique studies (3 randomized trials and 2 prospective and 4 retrospective studies) capturing 1266 unique patients were included. Of these, 1187 patients with 1189 incisions were included in the final analysis (52.3% male among 7 studies reporting data on sex; mean [SD] age, 52 [15] years among 8 studies reporting data on age). Significant clinical and methodologic heterogeneity existed among studies. On random-effects analysis, NPWT was associated with a significantly lower rate of SSI compared with standard dressings (pooled odds ratio [OR], 0.25; 95% CI, 0.12-0.52; P < .001). However, no difference in rates of seroma (pooled OR, 0.38; 95% CI, 0.12-1.23; P = .11) or wound dehiscence (pooled OR, 2.03; 95% CI, 0.61-6.78; P = .25) was found. On sensitivity analysis, focusing solely on colorectal procedures, NPWT significantly reduced SSI rates (pooled OR, 0.16; 95% CI, 0.07-0.36; P < .001).

Conclusions and Relevance

Application of NPWT on closed laparotomy wounds in general and colorectal surgery is associated with reduced SSI rates but similar rates of seroma and wound dehiscence compared with conventional nonpressure dressings.

Endoluminal Vacuum Therapy (E-Vac): A Treatment Option in Oesophagogastric Surgery

Background

Leaks from the upper gastrointestinal tract often pose a management challenge, particularly when surgical treatment has failed or is impossible. Vacuum therapy has revolutionised the treatment of wounds, and its role in enabling and accelerating healing is now explored in oesophagogastric surgery.

Methods

A piece of open cell foam is sutured around the distal end of a nasogastric tube using a silk suture. Under general anaesthetic, the foam covered tip is placed endoscopically through the perforation and into any extra-luminal cavity. Continuous negative pressure (125 mmHg) is then applied. Re-evaluation with change of the negative pressure system is performed every 48–72 h depending on the clinical condition. Patients are fed enterally and treated with broad-spectrum antibiotics and anti-fungal medication until healing, assessed endoscopically and/or radiologically, is complete.

Results

Since April 2011, twenty one patients have been treated. The cause of the leak was postoperative/iatrogenic complications (14 patients) and ischaemic/spontaneous perforation (seven patients). Twenty patients (95%) completed treatment successfully with healing of the defect and/or resolution of the cavity and were subsequently discharged from our care. One patient died from sepsis related to an oesophageal leak after withdrawing consent for further intervention following a single endoluminal vacuum (E-Vac) treatment. In addition, two patients who were successfully treated with E-Vac for their leak subsequently died within 90 days of E-Vac treatment from complications that were not associated with the E-Vac procedure. In two patients, E-Vac treatment was complicated by bleeding. The median number of E-Vac changes was 7 (range 3–12), and the median length of hospital stay was 35 days (range 23–152).

Conclusions

E-Vac therapy is a safe and effective treatment for upper gastrointestinal leaks and should be considered alongside more established therapies. Further research is now needed to understand the mechanism of action and to improve the ease with which E-Vac therapy can be delivered.

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.