Negative-pressure wound therapy for prevention and treatment of surgical-site infections after vascular surgery

A Biodegradable Janus Sponge for Negative Pressure Wound Therapy

Negative pressure wound therapy (NPWT) is effective in repairing serious skin injury. The dressing used in the NPWT is important for wound healing. In this paper, we develop biodegradable amphiphilic polyurethanes (PUs) and fabricate the PUs into sponges as wound dressings (Bi@e) with Janus pore architectures for NPWT. The Bi@e is adaptive to all the stages of the wound healing process. The Janus Bi@e sponge consists of two layers: the dense hydrophobic upper layer with small pores provides protection and support during negative pressure drainage, and the loose hydrophilic lower layer with large pores absorbs large amounts of wound exudate and maintains a moist environment. Additionally, antibacterial agent silver sulfadiazine (SSD) is loaded into the sponge against Escherichia coli and Staphylococcus aureus with a concentration of 0.50 wt%. The Janus sponge exhibits a super absorbent capacity of 19.53 times its own water weight and remarkable resistance to compression. In a rat skin defect model, the Janus Bi@e sponge not only prevents the conglutination between regenerative skin and dressing but also accelerates wound healing compared to commercially available NPWT dressing. The Janus Bi@e sponge is a promising dressing for the NPWT.

Reconstruction of foot and ankle defects using the vaccum sealing drainage versus the induced-membrane the elderly: A retrospective comparative study

The purpose of this study was to compare the reconstructive outcomes of soft-tissue defects around foot and ankle with vaccum sealing drainage (VSD) or induction membrane (IM) of cement formation and attempt to provide an optimal strategy for elderly patients. A retrospective review of all continuous patients with foot and ankle reconstruction using different flaps from October of 2016 and October of 2020 was performed. Based on the different way, the patients were divided into two groups: VSD group (n = 26) and IM group (n = 27). Outcomes were assessed according to the size of the defect, frequency of debridement procedures, hospitalization time, duration of healing, the healing rate, major amputation rate, functional outcomes and complications. Immunohistochemistry (IHC) detection of vascular endothelial growth factor (VEGF) was also be completed. We found that there was no difference in demographic characteristics, size of the defect, debridement times and functional outcomes between the two groups (p > 0.05); however, a significant difference in the wound healing time, hospitalization time and complications were noted between them(p < 0.05). The fresh granulation tissue of both groups showed abundant positive expression of VEGF. Thus, the VSD and IM are both available for foot and ankle reconstruction in elderly patients. However, the IM group offers short hospitalization time, duration of healing and lower frequency of postoperative complications. Thus, we advocate the IM for reconstruction of defects of the foot and ankle region in the elderly patients.

Infection of Vascular Prostheses: A Comprehensive Review

Vascular graft or endograft infection (VGEI) is a complex disease that complicates vascular-surgery and endovascular-surgery procedures and determines high morbidity and mortality. This review article provides the most updated general evidence on the pathogenesis, prevention, diagnosis, and treatment of VGEI. Several microorganisms are involved in VGEI development, but the most frequent one, responsible for over 75% of infections, is Staphylococcus aureus. Specific clinical, surgical, radiologic, and laboratory criteria are pivotal for the diagnosis of VGEI. Surgery and antimicrobial therapy are cornerstones in treatment for most patients with VGEI. For patients unfit for surgery, alternative treatment is available to improve the clinical course of VGEI.

Does Preventive Negative Pressure Wound Therapy (NPWT) reduce local complications following Lymph Node Dissection (LND) in the management of metastatic skin tumors?

INTRODUCTION

Axillary and inguinal lymph node dissection (LND) are performed in metastatic skin tumors with several local complications, such as lymphorrhea, lymphoceles, and lymphedema. The purpose of this study is to determine whether negative pressure wound therapy (NPWT) applied as a preventive measure could improve outcomes.

MATERIALS AND METHODS

A monocentric study included patients who underwent axillary or inguinal LND from May 2010 to March 2020, with a retrospective evaluation of prospectively collected data. Patients were divided into two groups: the conventional wound care (CWC) and the NPWT groups. Patients were systematically reviewed at D7, D30, and at 1 year postoperative, and data regarding lymphorrhea, lymphoceles, and lymphedema were collected.

RESULTS

A total of 109 axillary and inguinal LND were performed. NPWT was applied on 68 LND and CWC on 41 LND. The variables, diabetes, smoking, gender, associated treatments, and primary pathology (melanoma, squamous cell carcinoma, or Merkel tumors) were similar in both groups. Analyses have shown a significant difference in the rate of scar disunion during the first month between the two groups (p=0.045 between D1 and D7; p=0.011 between D8 and D30), as well as the presence of lymphorrhea (p=0.000 between D1 and D7; p=0.002 between D8 and D30). The rate of lymphoedema was significantly reduced in the NPWT group versus CWC (p=0.000 between D8 and D30; p=0.034 between D31 and 1 year).

CONCLUSION

NPWT reduces local complications (scar disunion, lymphorrhea, and lymphedema) during the first year following LND in the management of node metastatic skin tumors.

Prophylactic and Therapeutic Fasciotomy for Acute Compartment Syndrome after Revascularization for Acute Lower Limb Ischemia - Renal and Wound Outcomes

OBJECTIVES

Acute Compartment Syndrome (ACS) is a significant complication after revascularization for Acute Lower Limb Ischemia (ALI). High risk patients sometimes undergo prophylactic fasciotomy (PF) to prevent ACS. Patients that develop ACS undergo therapeutic fasciotomy (TF). The optimal timing of fasciotomy has been debated. The aim of this study was to describe and compare renal and wound outcomes in patients undergoing PF and TF.

METHODS

A retrospective cohort study including 76 patients undergoing PF (n=40) or TF (n=36) after revascularization for ALI between 2006 and 2018. Estimated Glomerular Filtration Rate (e-GFR) was used to evaluate renal function and compare within (paired-samples t-test) and between (ANOVA) groups. Wound complications and healing time were compiled from the complete wound healing period and compared between groups with Pearson's chi²- and log-rank test, respectively.

RESULTS

E-GFR improved over the in-hospital period with 8.2ml/min/1.73m² (95% CI 2.4-14.1, p=0.007) in the PF group and 4.4ml/min/1.73m² (95% CI 1.2-7.7, p=0.010) in the TF group, with no significant difference between the two groups (0.3ml/min/1.73m², 95% CI -6.7-7.4, p=0.93). The rate of wound infections was higher after TF (PF=60.6 % and TF=82.4 %, p=0.048), whereas rate of other wound complications (PF=61.3 % and TF=35.3%, p=0.036) was higher after PF.

CONCLUSION

Overall wound complications were high, whereas renal function improved during in-hospital stay. A more conservative approach to fasciotomy could avoid unnecessary fasciotomies and reduce wound complications, while have the potential to sufficiently preserve renal function if fasciotomy is needed for ACS. This would be possible and safe if an early diagnosis and treatment of ACS can be ensured.

Soft tissue reconstruction of complex infra-inguinal wounds following revisionary vascular surgery

INTRODUCTION

Large, full thickness infra-inguinal wounds following revision revascularization procedures of the lower extremity are a challenging complication for reconstructive surgery. Frequently, these patients present with various comorbidities and after several previous reconstructive attempts and therefore no straightforward soft tissue reconstruction is likely.

METHODS

Patients who presented with large, complex inguinal wounds for soft tissue reconstruction were analyzed retrospectively in terms of flap choice, outcome and complication rates. A focus was set on the reconstructive technique and a subgroup analysis was assessed.

RESULTS

19 patients (11 men, 8 women) who received 19 flaps (17 pedicled, two free flaps) were included in this retrospective study. Average patient age was 73.3 years (range: 53-88 years). 10 fascio-cutaneous flaps (ALT, 52.6%) and 9 muscle flaps (47.4%) were applied. Among muscle flaps, 3 pedicled gracilis flaps, 4 pedicled rectus abdominis flaps and two free latissimus dorsi flaps were used. No flap losses were observed except one case of limited distal flap necrosis (gracilis group). Body Mass Index (BMI) ranged from 19 to 37, mean 26.8. Mean surgery time in all patients was 165.9 minutes (range: 105-373 minutes). Revision surgery due to local wound healing problems averaged 1.6 in all patients. In all cases sufficient soft tissue reconstruction was achieved and bypasses were preserved. Lengths of stay averaged 27.2 (14 to 59 days). Mortality was considerably (10.5%) due to systemic complications (One patient died due to a heart attack 4 weeks postoperatively, another patient died due to an extensive pulmonary embolism two weeks postoperatively).

CONCLUSION

Soft tissue reconstruction of complex inguinal wounds after revision vascular surgery is challenging and wound-healing problems are expectable. In addition to the rectus abdominis flap the pedicled ALT flap is feasible in a broad variety of medium to large wounds. Free flap reconstruction is recommended for very large defects. A structured interdisciplinary approach is required for the management of complex wounds after vascular surgery to prevent and to deal with complications and perioperative morbidity.

Effect of prophylactic negative pressure treatment for post-surgery groin wounds management in vascular surgery: A meta-analysis

We performed a meta-analysis to evaluate the effect of prophylactic negative pressure treatment for post-surgery groin wounds management in vascular surgery. A systematic literature search up to April 2022 was performed and 1537 total number of groin vascular surgery incisions at the baseline of the studies; 729 of them were using the prophylactic negative pressure treatment, and 808 were using control. Odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of prophylactic negative pressure treatment for post-surgery groin wounds management in vascular surgery using the dichotomous, and contentious methods with a random or fixed-effect model. The prophylactic negative pressure treatment subjects had a significantly lower surgical site wound infection (OR, 0.26; 95% CI, 0.16-0.42, P < .001) in subjects after vascular surgery compared with control. However, prophylactic negative pressure treatment did not show any significant difference in revision surgery (OR, 0.73; 95% CI, 0.52-1.00, P = .05), readmission (OR, 0.93; 95% CI, 0.66-1.32, P = .69), mortality in hospital (OR, 0.54; 95% CI, 0.29-1.01, P = .05), and length of hospital stay (MD, -0.24; 95% CI, -0.91-0.44, P = .49) compared with control in subjects after vascular surgery. The prophylactic negative pressure treatment subjects had a significantly lower surgical site wound infection and no significant difference in revision surgery, readmission, mortality in hospital, and length of hospital stay compared with control in subjects after vascular surgery. The analysis of outcomes should be with caution because of the low sample size of 2 out of 10 studies in the meta-analysis and a low number of studies in certain comparisons.

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 January 2021, 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.

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. Our primary outcomes were SSI, mortality, and wound dehiscence.

MAIN RESULTS

In this fourth update, we added 18 new randomised controlled trials (RCTs) and one new economic study, resulting in a total of 62 RCTs (13,340 included participants) and six economic studies. Studies evaluated NPWT in a wide range of surgeries, including orthopaedic, obstetric, vascular and general procedures. All studies compared NPWT with standard dressings. Most studies had unclear or high risk of bias for at least one key domain. Primary outcomes Eleven studies (6384 participants) which reported mortality were pooled. There is low-certainty evidence showing there may be a reduced risk of death after surgery for people treated with NPWT (0.84%) compared with standard dressings (1.17%) but there is uncertainty around this as confidence intervals include risk of benefits and harm; risk ratio (RR) 0.78 (95% CI 0.47 to 1.30; I² = 0%). Fifty-four studies reported SSI; 44 studies (11,403 participants) were pooled. There is moderate-certainty evidence that NPWT probably results in fewer SSIs (8.7% of participants) than treatment with standard dressings (11.75%) after surgery; RR 0.73 (95% CI 0.63 to 0.85; I² = 29%). Thirty studies reported wound dehiscence; 23 studies (8724 participants) were pooled. There is moderate-certainty evidence that there is probably little or no difference in dehiscence between people treated with NPWT (6.62%) and those treated with standard dressing (6.97%), although there is imprecision around the estimate that includes risk of benefit and harms; RR 0.97 (95% CI 0.82 to 1.16; I² = 4%). Evidence was downgraded for imprecision, risk of bias, or a combination of these. Secondary outcomes There is low-certainty evidence for the outcomes of reoperation and seroma; in each case, confidence intervals included both benefit and harm. There may be a reduced risk of reoperation favouring the standard dressing arm, but this was imprecise: RR 1.13 (95% CI 0.91 to 1.41; I² = 2%; 18 trials; 6272 participants). There may be a reduced risk of seroma for people treated with NPWT but this is imprecise: the RR was 0.82 (95% CI 0.65 to 1.05; I² = 0%; 15 trials; 5436 participants). For skin blisters, there is low-certainty evidence that people treated with NPWT may be more likely to develop skin blisters compared with those treated with standard dressing (RR 3.55; 95% CI 1.43 to 8.77; I² = 74%; 11 trials; 5015 participants). The effect of NPWT on haematoma is uncertain (RR 0.79; 95 % CI 0.48 to 1.30; I² = 0%; 17 trials; 5909 participants; very low-certainty evidence). There is low-certainty evidence of little to no difference in reported pain between groups. Pain was measured in different ways and most studies could not be pooled; this GRADE assessment is based on all fourteen trials reporting pain; the pooled RR for the proportion of participants who experienced pain was 1.52 (95% CI 0.20, 11.31; I² = 34%; two studies; 632 participants). Cost-effectiveness Six economic studies, based wholly or partially on trials in our review, assessed the cost-effectiveness of NPWT compared with standard care. They considered NPWT in five indications: caesarean sections in obese women; surgery for lower limb fracture; knee/hip arthroplasty; coronary artery bypass grafts; and vascular surgery with inguinal incisions. They calculated quality-adjusted life-years or an equivalent, and produced estimates of the treatments' relative cost-effectiveness. The reporting quality was good but the evidence certainty 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 with primary closure of their surgical wound and treated prophylactically with NPWT following surgery probably experience fewer SSIs  than people treated with standard dressings but there is probably no difference in wound dehiscence (moderate-certainty evidence). There may be a reduced risk of death after surgery for people treated with NPWT compared with standard dressings but there is uncertainty around this as confidence intervals include risk of benefit and harm (low-certainty evidence). People treated with NPWT may experience more instances of skin blistering compared with standard dressing treatment (low-certainty evidence). There are no clear differences in other secondary outcomes where most evidence is low or very low-certainty. 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.

Circular RNA Expression Profiles Following Negative Pressure Wound Therapy in Burn Wounds with Experimental Pseudomonas aeruginosa Infection

Infections of burn wounds, especially those caused by Pseudomonas aeruginosa, could trigger sepsis or septic shock, which is the main cause of death after burn injury. Compared with traditional saline-wet-to-dry dressings, negative pressure wound therapy (NPWT) is more effective for the prevention and treatment of wound infections. However, the mechanism by which NPWT controls infection and accelerates wound healing remains unclear. Accordingly, in this study, the molecular mechanisms underlying the effects of NPWT were explored using a murine model of P. aeruginosa-infected burn wounds. NPWT significantly reduced P. aeruginosa levels in wounds, enhanced blood flow, and promoted wound healing. Additionally, NPWT markedly alleviated wound inflammation and increased the expression of wound healing–related molecules. Recent evidence points to a role of circular RNAs (circRNAs) in wound healing; hence, whole-transcriptome sequencing of wound tissues from NPWT and control groups was performed to evaluate circRNA expression profiles. In total, 12 up-regulated and 25 down-regulated circRNAs were identified between groups. Among these, five significant differentially expressed circRNAs acting as microRNA sponges were identified, and their predicted targets were verified by reverse transcription-quantitative polymerase chain reaction. These results further support the roles of circRNAs in wound healing by NPWT and the prevention of P. aeruginosa infection, providing key molecular targets for further functional analyses.

Healthcare professionals' experiences of being observed regarding hygiene routines: the Hawthorne effect in vascular surgery

Background

The Hawthorne Effect is the change in behaviour by subjects due to their awareness of being observed and is evident in both research and clinical settings as a result of various forms of observation. When the Hawthorne effect exists, it is short-lived, and likely leads to increased productivity, compliance, or adherence to standard protocols. This study is a qualitative component of an ongoing multicentre study, examining the role of Incisional Negative Pressure Wound Therapy after vascular surgery (INVIPS Trial). Here we examine the factors that influence hygiene and the role of the Hawthorne effect on the adherence of healthcare professionals to standard hygiene precautions.

Methods

This is a qualitative interview study, investigating how healthcare professionals perceive the observation regarding hygiene routines and their compliance with them. Seven semi-structured focus group interviews were conducted, each interview included a different staff category and one individual interview with a nurse from the Department for Communicable Disease Control. Additionally, a structured questionnaire interview was performed with environmental services staff. The results were analysed based on the inductive qualitative content analysis approach.

Results

The analysis revealed four themes and 12 subthemes. Communication and hindering hierarchy were found to be crucial. Healthcare professionals sought more personal and direct feedback. All participants believed that there were routines that should be adhered to but did not know where to find information on them. Staff in the operating theatre were most meticulous in adhering to standard hygiene precautions. The need to give observers a clear mandate and support their work was identified. The staff had different opinions concerning the patient’s awareness of the importance of hygiene following surgery. The INVIPS Trial had mediated the Hawthorne effect.

Conclusion

The results of this study indicate that the themes identified, encompassing communication, behaviour, rules and routines, and work environment, influence the adherence of healthcare professionals to standard precautions to a considerable extent of which many factors could be mediated by a Hawthorne effect. It is important that managers within the healthcare system put into place an improved and sustainable hygiene care to reduce the rate of surgical site infections after vascular surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06097-5.

A multicenter, prospective randomized trial of negative pressure wound therapy for infrainguinal revascularization with a groin incision

BACKGROUND

Wound complications after open infrainguinal revascularization are a frequent cause of patient morbidity, resulting in increased healthcare costs. The purpose of the present study was to assess the effects of closed incision negative pressure therapy (ciNPT) on groin wound complications after infrainguinal bypass and femoral endarterectomy.

METHODS

A total of 242 patients who had undergone infrainguinal bypass (n = 124) or femoral endarterectomy (n = 118) at five academic medical centers in New England from April 2015 to August 2019 were randomized to ciNPT (PREVENA; 3M KCI, St Paul, Minn; n = 118) or standard gauze (n = 124). The primary outcome measure was a composite endpoint of groin wound complications, including surgical site infections (SSIs), major noninfectious wound complications, or graft infections within 30 days after surgery. The secondary outcome measures included 30-day SSIs, 30-day noninfectious wound complications, readmission for wound complications, significant adverse events, and health-related quality of life using the EuroQoL 5D-3L survey.

RESULTS

The ciNPT and control groups had similar demographics (age, 67 vs 67 years, P = .98; male gender, 71% vs 70%, P = .86; white race, 93% vs 93%, P = .97), comorbidities (previous or current smoking, 93% vs 94%, P = .46; diabetes, 41% vs 48%, P = .20; renal insufficiency, 4% vs 7%, P = .31), and operative characteristics, including procedure type, autogenous conduit, and operative time. No differences were found in the primary composite outcome at 30 days between the two groups (ciNPT vs control: 31% vs 28%; P = .55). The incidence of SSI at 30 days was similar between the two groups (ciNPT vs control: 11% vs 12%; P = .58). Infectious (13.9% vs 12.6%; P = .77) and noninfectious (20.9% vs 17.6%; P = .53) wound complications at 30 days were also similar for the ciNPT and control groups. Wound complications requiring readmission also similar between the two groups (ciNPT vs control: 9% vs 7%; P = .54). The significant adverse event rates were not different between the two groups (ciNPT vs control: 13% vs 16%; P = .53). The mean length of the initial hospitalization was the same for the ciNPT and control groups (5.2 vs 5.7 days; P = .63). The overall health-related quality of life was similar at baseline and at 14 and 30 days postoperatively for the two groups. Although not powered for stratification, we found no differences among the subgroups in gender, obesity, diabetes, smoking, claudication, chronic limb threatening ischemia, bypass, or endarterectomy. On multivariable analysis, no differences were found in wound complications at 30 days for the ciNPT vs gauze groups (odds ratio, 1.4; 95% confidence interval, 0.8-2.6; P = .234).

CONCLUSIONS

In contrast to other randomized studies, our multicenter trial of infrainguinal revascularization found no differences in the 30-day groin wound complications for patients treated with ciNPT vs standard gauze dressings. However, the SSI rate was lower in the control group than reported in other studies, suggesting other practice patterns and processes of care might have reduced the rate of groin infections. Further study might identify the subsets of high-risk patients that could benefit from ciNPT.

Effectiveness and Safety of Biodegradable Calcium Sulfate Antibiotic Beads as Adjuvant Therapy in Vascular Graft Infections

This is a retrospective cohort study evaluating the safety and effectiveness of biodegradable calcium sulfate antibiotic beads in vascular graft infections compared with standard of care. No differences in acute kidney injury or hypercalcemia were observed between the cohorts. Recurrence of infection did not occur in the 13-patient bead cohort compared with 14 patients who had recurrence in the 45-patient nonbead cohort with a number needed to treat of 4.0.

Analysis of the influence of transgenic kalanchoe extract with cecropin P1 on the state of a non-infected wound in rats

In this article data on the analysis of the effect of transgenic Kalanchoe pinnate extract with cecropin P1 on the state of uninfected wounds in rats are presented. The study used Wistar rats weighing 220 ± 20 g. A wound of 20 × 20 mm was modeled under anesthesia in sterile conditions. The wound was treated during 14 days with the 3% hydrogen peroxide solution in all experimental groups. Additional treatment with the 10% cefazolin solution was used in group No. 2; with Kalanchoe juice it was used in group No. 3, and with transgenic Kalanchoe extract cecropin P1 it was used in group No. 4. The effectiveness of the treatment of the wound process was evaluated by the external state of the wound and planimetry indicators. It was found that all analyzed parameters of the experimental groups were better than in the control group of animals. However, the effect was most pronounced in the group treated by transgenic Kalanchoe extract with cecropin P1, The results of the study allow us to recommend further preclinical study of the substance for the possible treatment of trophic ulcers in patients with diabetes mellitus.

Postoperative negative pressure wound therapy is associated with decreased surgical site infections in all lower extremity amputations

Introduction

We hypothesize that Negative Pressure Wound Therapy (NPWT) is associated with a lower incidence of surgical site infection (SSI) in lower extremity amputations (LEAs), a potentially devastating complication.

Methods

NSQIP database from 2011 to 2018 was queried to identify all-level LEAs. Cases using NPWT were identified. One-to-one nearest-neighbor propensity score matching was performed using a binary logistic regression on NPWT status controlling for patient comorbidities.

Results

NPWT was used in 133 of 5237 total LEAs (2.54%). Compared to propensity score-matched controls, they had significantly fewer SSIs (1.50% vs. 8.27%).

Conclusions

NPWT was associated with lower incidence of SSI.

Outcomes of Exploratory Laparotomy and Abdominal Infections Among Combat Casualties

BACKGROUND

Abdominal injuries historically account for 13% of battlefield surgical procedures. We examined the occurrence of exploratory laparotomies and subsequent abdominal surgical site infections (SSIs) among combat casualties.

METHODS

Military personnel injured during deployment (2009-2014) were included if they required a laparotomy for combat-related trauma and were evacuated to Landstuhl Regional Medical Center, Germany, before being transferred to participating US military hospitals.

RESULTS

Of 4304 combat casualties, 341 (7.9%) underwent laparotomy. Including re-explorations, 1053 laparotomies (median, 2; interquartile range, 1-3; range, 1-28) were performed with 58% occurring within the combat zone. Forty-nine (14.4%) patients had abdominal SSIs (four with multiple SSIs): 27 (7.9%) with deep space SSIs, 14 (4.1%) with a deep incisional SSI, and 12 (3.5%) a superficial incisional SSI. Patients with abdominal SSIs had larger volume of blood transfusions (median, 24 versus 14 units), more laparotomies (median, 4 versus 2), and more hollow viscus injuries (74% versus 45%) than patients without abdominal SSIs. Abdominal closure occurred after 10 d for 12% of the patients with SSI versus 2% of patients without SSI. Mesh adjuncts were used to achieve fascial closure in 20.4% and 2.1% of patients with and without SSI, respectively. Survival was 98% and 96% in patients with and without SSIs, respectively.

CONCLUSIONS

Less than 10% of combat casualties in the modern era required abdominal exploration and most were severely injured with hollow viscus injuries and required massive transfusions. Despite the extensive contamination from battlefield injuries, the SSI proportion is consistent with civilian rates and survival was high.

Closed-incision negative-pressure wound management in surgery—literature review and recommendations

Background

Wound healing deficits and subsequent surgical site infections are potential complications after surgical procedures, resulting in increased morbidity and treatment costs. Closed-incision negative-pressure wound therapy (ciNPWT) systems seem to reduce postoperative wound complications by sealing the wound and reducing tensile forces.

Materials and methods

We conducted a collaborative English literature review in the PubMed database including publications from 2009 to 2020 on ciNPWT use in five surgical subspecialities (orthopaedics and trauma, general surgery, plastic surgery, cardiac surgery and vascular surgery). With literature reviews, case reports and expert opinions excluded, the remaining 59 studies were critically summarized and evaluated with regard to their level of evidence.

Results

Of nine studies analysed in orthopaedics and trauma, positive results of ciNPWT were reported in 55.6%. In 11 of 13 (84.6%), 13 of 15 (86.7%) and 10 of 10 (100%) of studies analysed in plastic, vascular and general surgery, respectively, a positive effect of ciNPWT was observed. On the contrary, only 4 of 12 studies from cardiac surgery discovered positive effects of ciNPWT (33.3%).

Conclusion

ciNPWT is a promising treatment modality to improve postoperative wound healing, notably when facing increased tensile forces. To optimise ciNPWT benefits, indications for its use should be based on patient- and procedure-related risk factors.

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.

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.

Outcomes of incisional negative pressure wound therapy following brachiobasilic transposition arteriovenous fistula creation: A 1:2 propensity score matched study

Incisional negative wound pressure therapy (iNPWT) use on closed incisions has been shown to improve wound outcomes, but no studies have evaluated the use of iNPWT following brachiobasilic transposition arteriovenous fistula (BBT-AVF). We aim to investigate the efficacy of iNPWT vs conventional wound therapy in reducing surgical site infections (SSIs) for BBT-AVF incisions. This is a retrospective cohort study of patients who underwent BBT-AVF creation between January 2010 and December 2017. A 1:2 propensity score matching (PSM) was performed to reduce selection bias and address for confounding factors. Study outcomes included SSI and haematoma incidence, 30-day readmission, and 30-day mortality. A total of 154 patients were reviewed in this study: 47 (30.5%) had iNPWT and 107 (69.5%) had conventional wound therapy. The overall median age was 60.5 (interquartile range 54-69). PSM with a 1:2 ratio resulted in a total of 117 patients (39 iNPWT and 78 conventional wound therapy). In the unmatched cohort, SSI incidence was lower in the iNPWT group (n = 1/47 [2.1%] vs n = 14/107 [13.1%], P = .035). However, incidence of SSI was comparable between iNPWT and conventional wound therapy after matching (n = 1/39 [2.6%] vs n = 9/78 [11.5%], P = .102). There was no significant difference in 30-day readmission and 30-day mortality. Within our study population of patients with BBT-AVF incisions, there is a non-statistically significant reduction in SSI incidence for patients who received iNPWT as compared with conventional wound therapy. Further prospective randomised controlled studies should be conducted to validate these findings.

Clinical Applications and Benefits of Using Closed-incision Negative Pressure Therapy with Novel Dressing: A Review Article

Surgical site occurrences (SSOs) are common in patients undergoing operative procedures, especially in the form of surgical site infections (SSIs). Multiple studies show that obesity, tobacco use, prolonged surgical time, and diabetes mellitus are the major risk factors for SSIs. SSIs increase healthcare costs and often result in morbidity. Many surgeons are currently using closed-incision negative pressure therapy (ciNPT) to counter SSIs. This method makes it easier for them to manage closed and surgical incisions. This technique has already been applied in the plastic surgery field. This study discusses how the use of ciNPT is helping surgeons to reduce complications related to SSOs. The technique has been reported to minimize the rate of reoperations, readmissions, and other wound-related complications. Using ciNPT with novel dressing has proved to be a significantly effective clinical intervention method in managing clean and closed wounds. The novel dressing protects the incision from external contamination and minimizes lateral tension.

Circular pOlyethylene drape in preVEntion of suRgical site infection (COVER trial): study protocol for a randomised controlled trial

INTRODUCTION

Surgical site infection (SSI) after abdominal surgery remains a significant cause of morbidity and is associated with an increased socioeconomic burden and a reduced quality of life. Circular wound protectors have been expected to reduce the risk of SSI, but previous studies reported conflicting results on their protective effects. The purpose of this study was to evaluate the efficacy of circular wound protectors in reducing SSI in open abdominal surgery.

METHODS AND ANALYSIS

The circular pOlyethylen drape in preVEntion of suRgical site infection (COVER) trial investigates whether the application of a dual-ring circular plastic wound protector reduces the rate of SSI in patients undergoing elective or emergent open abdominal surgery related to the gastrointestinal tract, regardless of the type of wound classified by the Centers for Disease Control. The COVER trial is a multicentre, randomised controlled clinical trial with two parallel arms-one using a dual-ring wound protector with circular polyethylene drape and the other using conventional surgical dressing gauze. The primary outcome will measure the rate of SSI within 30 days after surgery in two groups. Statistical analysis of the primary end point will be based on the intention-to-treat population. The sample size was determined to achieve a study power of 80% with 95% two-sided confidence limits. Considering a dropout rate of up to 5%, a total of 458 patients, 229 patients in each group, will be enrolled in this study.

ETHICS AND DISSEMINATION

The trial protocol and informed consent document have been reviewed and approved by the institutional review board at each participating centre. Written informed consent will be obtained from each study participant. The clinical outcomes of this trial will be submitted to an international peer-reviewed journal and presented at international conferences.

TRIAL REGISTRATION NUMBER

NCT03170843.

Incisional negative pressure wound therapy for the prevention of surgical site infection after open lower limb revascularization - Rationale and design of a multi-center randomized controlled trial

Introduction

Lower limb revascularization with inguinal incisions is a common vascular surgical procedure. Due to risk of injury to lymphatic vessels and a diverse bacterial flora in the groin, surgical site infections (SSI) represent a common and sometimes life-threatening complication. While transverse incisions in endovascular aneurysm repair has a low SSI rate, vertical incisions in thrombendarterectomy (TEA) has a higher risk and bypass the highest risk. This randomized controlled trial (RCT) will investigate the protective role of negative pressure wound therapy (NPWT) on closed inguinal incisions in elective vascular surgery undergoing TEA and bypass procedures, respectively, to prevent SSI.

Methods

This RCT registered at ClinicalTrials.gov (Identifier: NCT01913132) compares the effects of a NPWT dressing (PICO™, Smith & Nephew, UK) to standard wound dressing on postoperative SSI. The multi-center study includes two distinct vascular procedures with different SSI risk profiles: TEA and lower limb bypass. Three hundred and fifty-eight groin incisions are anticipated to be included in the TEA group and 133 inguinal incisions in the bypass group. Bilateral inguinal incisions will be randomized to NPWT in one groin and control dressing in the contralateral groin, and this dependency was accounted for in sample size calculation and will be addressed in data analysis.

Discussion

This RCT attempts to evaluate the potential benefit of NPWT on closed inguinal incisions after two distinct vascular procedures at high risk of SSI. Outcome of this trial could have implications on postoperative wound care in both vascular and non-vascular surgical patients.

Dermabond and Tegaderm: A Better Surgical Incision Dressing

Surgical site infections (SSIs) are a common source of morbidity with vascular surgery incisions, especially in the groin. Single institution case series have widely varying, but high incidences of groin wound infection after open lower extremity revascularization. Optimally, a dressing that did not require changes, had low cost, and was water resistant would be optimal in these patients. We developed and validate a new dressing utilizing Dermabond (Ethibond™) and Tegaderm™ for vascular surgery incisions that could simplify and reduce postoperative SSIs. In this initial experience, we reviewed 94 patients. Of the 94 patients, 0 had signs of infection superficial or deep, dehiscence, or evidence of nonhealing. Gluing a Tegaderm to an incision using Dermabond is a novel and easy way to perform dressing that reduces wound infection, increases patient comfort, avoids dressing changes, and allows visualization of the wound.

Meta-analysis and trial sequential analysis of prophylactic negative pressure therapy for groin wounds in vascular surgery

BACKGROUND

Negative pressure therapy has been proposed as a prophylactic measure to promote surgical wound healing and reduce surgical site complications.

METHODS

We conducted a systematic review of the literature to identify randomized controlled trials (RCTs) comparing prophylactic negative pressure therapy with standard practice in closed groin incisions in vascular surgery. We calculated the pooled odds ratio (OR) or risk difference and 95% confidence interval (CI) with the use of the fixed-effect model. To control the risk of type I error, we adjusted the thresholds for the Z-values with the use of the O'Brien-Fleming α-spending function, and the risk of type II error was controlled with the use of the β-spending function and futility boundaries.

RESULTS

We selected six RCTs reporting on a total of 733 groin wounds. Patients with negative pressure wound therapy had a lower risk of developing surgical site infection (OR, 0.36; 95% CI, 0.24-0.54; P < .001), a lower risk of revision surgery (OR, 0.44; 95% CI, 0.22-0.88; P = .02) and a shorter hospital stay (weighted mean difference, -2.14; 95% CI, -3.78 to 0.49; P = .01). There was no difference in in-hospital mortality (risk difference, 0.01; 95% CI, -0.02 to 0.05; P = .53) or readmission (OR, 0.46; 95% CI, 0.17-1.29; P = .14). The Z-curve for surgical site infection crossed the O'Brien-Fleming significance boundaries for superiority (before the required information size was reached).

CONCLUSIONS

Prophylactic negative pressure wound therapy confers improved outcomes in patients undergoing arterial surgery via a groin incision compared with standard surgical wound care.

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). While existing evidence for the effectiveness of NPWT remains uncertain, new trials necessitated an updated review of the evidence for the effects of NPWT on postoperative wounds healing by primary closure.

OBJECTIVES

To assess the effects of negative pressure wound therapy for preventing surgical site infection in wounds healing through primary closure.

SEARCH METHODS

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

Four review authors independently assessed trials using predetermined inclusion criteria. We carried out data extraction, 'Risk of bias' assessment using the Cochrane 'Risk of bias' tool, and quality assessment according to GRADE methodology.

MAIN RESULTS

In this second update we added 25 intervention trials, resulting in a total of 30 intervention trials (2957 participants), and two economic studies nested in trials. Surgeries included abdominal and colorectal (n = 5); caesarean section (n = 5); knee or hip arthroplasties (n = 5); groin surgery (n = 5); fractures (n = 5); laparotomy (n = 1); vascular surgery (n = 1); sternotomy (n = 1); breast reduction mammoplasty (n = 1); and mixed (n = 1). In three key domains four studies were at low risk of bias; six studies were at high risk of bias; and 20 studies were at unclear risk of bias. We judged the evidence to be of low or very low certainty for all outcomes, downgrading the level of the evidence on the basis of risk of bias and imprecision.Primary outcomesThree studies reported mortality (416 participants; follow-up 30 to 90 days or unspecified). It is uncertain whether NPWT has an impact on risk of death compared with standard dressings (risk ratio (RR) 0.63, 95% confidence interval (CI) 0.25 to 1.56; very low-certainty evidence, downgraded once for serious risk of bias and twice for very serious imprecision).Twenty-five studies reported on SSI. The evidence from 23 studies (2533 participants; 2547 wounds; follow-up 30 days to 12 months or unspecified) showed that NPWT may reduce the rate of SSIs (RR 0.67, 95% CI 0.53 to 0.85; low-certainty evidence, downgraded twice for very serious risk of bias).Fourteen studies reported dehiscence. We combined results from 12 studies (1507 wounds; 1475 participants; follow-up 30 days to an average of 113 days or unspecified) that compared NPWT with standard dressings. It is uncertain whether NPWT reduces the risk of wound dehiscence compared with standard dressings (RR 0.80, 95% CI 0.55 to 1.18; very low-certainty evidence, downgraded twice for very serious risk of bias and once for serious imprecision).Secondary outcomesWe are uncertain whether NPWT increases or decreases reoperation rates when compared with a standard dressing (RR 1.09, 95% CI 0.73 to 1.63; 6 trials; 1021 participants; very low-certainty evidence, downgraded for very serious risk of bias and serious imprecision) or if there is any clinical benefit associated with NPWT for reducing wound-related readmission to hospital within 30 days (RR 0.86, 95% CI 0.47 to 1.57; 7 studies; 1271 participants; very low-certainty evidence, downgraded for very serious risk of bias and serious imprecision). It is also uncertain whether NPWT reduces incidence of seroma compared with standard dressings (RR 0.67, 95% CI 0.45 to 1.00; 6 studies; 568 participants; very low-certainty evidence, downgraded twice for very serious risk of bias and once for serious imprecision). It is uncertain if NPWT reduces or increases the risk of haematoma when compared with a standard dressing (RR 1.05, 95% CI 0.32 to 3.42; 6 trials; 831 participants; very low-certainty evidence, downgraded twice for very serious risk of bias and twice for very serious imprecision. It is uncertain if there is a higher risk of developing blisters when NPWT is compared with a standard dressing (RR 6.64, 95% CI 3.16 to 13.95; 6 studies; 597 participants; very low-certainty evidence, downgraded twice for very serious risk of bias and twice for very serious imprecision).Quality of life was not reported separately by group but was used in two economic evaluations to calculate quality-adjusted life years (QALYs). There was no clear difference in incremental QALYs for NPWT relative to standard dressing when results from the two trials were combined (mean difference 0.00, 95% CI -0.00 to 0.00; moderate-certainty evidence).One trial concluded that NPWT may be more cost-effective than standard care, estimating an incremental cost-effectiveness ratio (ICER) value of GBP 20.65 per QALY gained. A second cost-effectiveness study estimated that when compared with standard dressings NPWT was cost saving and improved QALYs. We rated the overall quality of the reports as very good; we did not grade the evidence beyond this as it was based on modelling assumptions.

AUTHORS' CONCLUSIONS

Despite the addition of 25 trials, results are consistent with our earlier review, with the evidence judged to be of low or very low certainty for all outcomes. Consequently, uncertainty remains about whether NPWT compared with a standard dressing reduces or increases the incidence of important outcomes such as mortality, dehiscence, seroma, or if it increases costs. Given the cost and widespread use of NPWT for SSI prophylaxis, there is an urgent need for larger, well-designed and well-conducted trials to evaluate the effects of newer NPWT products designed for use on clean, closed surgical incisions. Such trials should initially focus on wounds that may be difficult to heal, such as sternal wounds or incisions on obese patients.

Closed Incision Negative Pressure Therapy Reduces Surgical Site Infections in Vascular Surgery: A Prospective Randomised Trial (AIMS Trial)

BACKGROUND

Surgical site infections (SSIs) of the groin remain a crucial problem in vascular surgery, prompting great interest in preventative techniques, such as closed incision negative pressure therapy (ciNPT). This prospective randomised study aimed to assess the potential benefits of ciNPT application after groin incisions for vascular surgery.

METHOD

The study included 204 patients who underwent vascular surgery for peripheral artery disease (PAD) at two sites between July 2015 and May 2017. These patients received post-operative treatment with ciNPT (intervention group) or standard wound dressings (control group). After exclusion, 188 patients were assessed for SSIs using the Szilagyi classification.

RESULTS

The mean patient age was 66.6 ± 9.4 years (range 43-85 years), and 70% were male (n = 132). Regarding PAD stage, 52% were stage IIB, 28% stage III, and 19% stage IV. Among the patients, 45% (n = 85) had had a previous groin incision. Bacterial swabs were performed in each case of suspected SSI (22.8% [43/188]), while 76.7% (33/188) were negative, there were 5% [5/98] positive swabs in the intervention group and 5.5% [5/90] in the control group). Antibiotics were given to 13.2% of the intervention group, and 31.1% of the control group (p = .004). The control group experienced more frequent SSIs (33.3%; 30/90) than the intervention group (13.2%; 13/98; p = .0015; absolute risk difference -20.1 per 100; 95% CI -31.9 to 8.2). This difference was based on an increased rate of Szilagyi I SSI in the control group (24.6% vs. 8.1%, p = .0012).

CONCLUSION

The results confirmed a reduced superficial SSI rate after vascular surgical groin incision using ciNPT compared with standard wound dressings.

Surgical infection

Real and present danger

Use of Negative Pressure Wound Therapy for Lower Limb Bypass Incisions

Objective: The use of negative pressure wound therapy (NPWT) for post-surgical cardiothoracic, orthopedic, plastic, and obstetric and gynecologic procedures has been described. However, there are no data regarding its use for lower limb bypass incisions. We aimed to investigate the outcomes of NPWT in preventing surgical site infection (SSI) in patients with lower limb arterial bypass incisions.

Materials and Methods: We retrospectively used data of 42 patients who underwent lower limb arterial bypass with reversed great saphenous vein between March 2014 and June 2016 and compared conventional wound therapy and NPWT with regard to preventing SSI.

Results: Twenty-eight (67%) patients underwent conventional wound therapy and 14 (33%) underwent NPWT. There were no statistical differences regarding patient characteristics and mean SSI risk scores between the two patient groups (13.7% for conventional wound therapy vs. 13.4% for NPWT; P=0.831). In the conventional group, nine instances of SSI (32%) and three (11%) of these required subsequent surgical wound debridement, whereas in the NPWT group, there was no SSI incidence (P=0.019). Secondary outcomes such as the length of hospital stay, 30-day readmission rate, and need for secondary vascular procedures were not statistically different between the two groups.

Conclusion: The use of NPWT for lower limb arterial bypass incisions is superior to that of conventional wound therapy because it may prevent SSIs.