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Negative pressure wound therapy for skin grafts and surgical wounds healing by primary intention

  1. Joan Webster1,2,3,*,
  2. Paul Scuffham4,
  3. Karen L Sherriff5,
  4. Monica Stankiewicz6,
  5. Wendy P Chaboyer5

Editorial Group: Cochrane Wounds Group

Published Online: 18 APR 2012

Assessed as up-to-date: 18 NOV 2011

DOI: 10.1002/14651858.CD009261.pub2


How to Cite

Webster J, Scuffham P, Sherriff KL, Stankiewicz M, Chaboyer WP. Negative pressure wound therapy for skin grafts and surgical wounds healing by primary intention. Cochrane Database of Systematic Reviews 2012, Issue 4. Art. No.: CD009261. DOI: 10.1002/14651858.CD009261.pub2.

Author Information

  1. 1

    Royal Brisbane and Women's Hospital, Centre for Clinical Nursing, Brisbane, Queensland, Australia

  2. 2

    Griffith University, NHMRC Centre for Research Excellence in Nursing, Centre for Health Practice Innovation, Griffith Health Institute, Brisbane, Queensland, Australia

  3. 3

    University of Queensland, School of Nursing and Midwifery, Brisbane, Queensland, Australia

  4. 4

    Griffith University, Meadowbrook, Australia

  5. 5

    Griffith University, NHMRC Centre of Research Excellence in Nursing, Brisbane, Queensland, Australia

  6. 6

    Royal Brisbane and Women's Hospital, Specialist Outpatient Department, Herston, Queensland, Australia

*Joan Webster, joan_webster@health.qld.gov.au.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 18 APR 2012

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Background

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Description of the condition

It is estimated that between 187 and 281 million operations are carried out annually worldwide, equating to one operation each year for every 25 people (WHO 2009). This figure is higher in developed countries. For example, in Australia in 2008/09 it can be calculated from hospital statistics that there was one elective surgical procedure for every 12.4 people (Australian Institute of Health and Welfare 2010).

Surgical wounds, including skin grafts, generally heal by primary intention where the wound edges are brought together so that they are adjacent to each other. Wound closure is usually assisted using sutures (stitches), staples, adhesive tape or glue (Coulthard 2010) and healing begins within hours of closure (Rodero 2010). However, some types of surgical wounds, such as skin grafts (Culliford 2007) and sternal wounds (Schimmer 2008), are more difficult to heal due to their anatomical position or an increased likelihood of infection. So too are surgical wounds in certain types of patients, such as the morbidly obese (Waisbren 2010).

Failure of a wound to heal may be due to underlying patient characteristics such as age or medical conditions, including malnutrition, obesity, uncontrolled diabetes, cardiovascular disease, compromised immunity or infection (Baronski 2008). It may also be the result of dehiscence, or separation of the wound edges. Reasons for dehiscence are either technical, such as sutures breaking, cutting through tissue or knots slipping, or inadequate splinting (Baronski 2008) or related to patient factors, such as those listed above and particularly wound infection (Ortega 2010). Chronic obstructive pulmonary disease is a major risk factor for dehiscence in sternal surgery (Olbrecht 2006). The most serious complication of dehiscence is wound evisceration, where the wound completely separates, exposing the underlying organs (Harvey 2005).

 

Description of the intervention

Negative pressure wound therapy (NPWT) has been used to treat wounds since the late 1990s (Fleischmann 1997; Morykwas 1997). NPWT is recommended for a diverse range of lesions including open abdominal wounds (Stevens 2009), open fractures (Stannard 2009), skin graft donor sites (Chio 2010), acute burns (Molnar 2005), pressure ulcers (Mandal 2007), post-traumatic wounds (Kanakaris 2007), diabetic foot ulcers (Eneroth 2008), split-thickness skin grafts (Blume 2010), sternal wounds (Sjogren 2011) and, more recently, after clean surgery in obese patients (Dragu 2010). NPWT is used prophylactically following skin grafts and clean surgery to prevent a surgical site complication, in contrast to its more frequent use in wounds healing by secondary intention (left open to heal from the bottom up) such as chronic or infected wounds.

NPWT consists of a closed, sealed system that produces negative pressure (suction) to the wound surface. The wound is covered or packed with an open-cell foam or gauze dressing and sealed with an occlusive drape. Intermittent or continuous suction is maintained by connecting suction tubes from the wound dressing to a vacuum pump and liquid waste collector. Standard negative pressure rates range between 50 and 125 mm Hg (Ubbink 2008; Vikatmaa 2008). The longest established device is the vacuum-assisted closure ((VAC® KCI, San Antonio, Texas) system (Morykwas 1997) however alternatives have been developed and are being used (Llanos 2006; Mody 2008; Rozen 2008).         

 

How the intervention might work

In humans, the wound healing process is regarded as occurring in three consecutive and overlapping stages: inflammation, new tissue formation and remodelling (Gurtner 2008). The precise way in which NPWT may aid this process is not clear. Experimental evidence suggests that NPWT may assist wound healing by increasing local blood flow and granulation tissue and, reducing bacterial contamination, oedema and exudate. There may be other changes to the microenvironment of the wound (Banwell 2003). One of the basic theoretical principles underpinning the development of NPWT is that it increases perfusion or blood flow, but this has been recently challenged. In an experimental study, using healthy volunteers local blood flow decreased as suction pressure increased (Kairinos 2009).

 

Why it is important to do this review

Wounds that fail to heal may cause considerable distress to patients and impact negatively on the physical, social, emotional and economic aspects of their life (Andersson 2010). Investigations into interventions to avoid wound breakdown are therefore important. NPWT was approved by the American Food and Drug Administration (FDA) for the treatment of non-healing wounds in 1995 (Kloth 2002). More recently, a multi-national expert working group has issued guidelines for the use of the therapy for diabetic foot ulcers, complex leg ulcers, pressure ulcers, dehisced sternal wounds, open abdominal wounds and traumatic wounds (Expert Working Group 2008). While NPWT has become an accepted part of modern wound healing techniques, there have also been reports of severe adverse events associated with the therapy. Problems have included stomal dehiscence (Steenvoorde 2009), extraperitoneal bladder leakage (Heuser 2005), necrotising fasciitis (Citak 2010), bleeding after cardiac surgery (Petzina 2010) and pain (Apostoli 2008) and anxiety (Keskin 2008). Communiqués issued in 2009 by the FDA reported six deaths and 77 injury reports associated with the use of NPWT. The information sheets contained warnings and recommendations for consumers and healthcare practitioners about use of the treatment in certain circumstances (FDA 2009a; FDA 2009b).

Although several reviews of NPWT have been published, none has focused specifically on postoperative wounds expected to heal by primary intention (Gregor 2008; Ubbink 2008; Vikatmaa 2008); nor have any included an economic analysis. In addition, although publication bias has been noted, both in terms of the majority of trials being funded by manufacturers (Vikatmaa 2008) and premature termination of studies (Gregor 2008), no sub-analyses to control for these potential biases have been conducted. Recent reviews have concluded that the evidence for the effectiveness of NPWT remains uncertain, however, this is an evolving therapy and the indications for its use are widening. Consequently, a systematic review to summarise evidence on the effects of NPWT on the healing of surgical wounds healing by primary intention is required.

 

Objectives

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

To assess the effects of NPWT on surgical wounds (including skin grafts) that are expected to heal by primary intention.

 

Methods

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Criteria for considering studies for this review

 

Types of studies

We included only randomised controlled trials (RCTs) that evaluated the effects of NPWT on the healing of surgical wounds. Surgical wounds included split skin grafts, full skin grafts or any primary wound closure. This criterion encompassed comparative full and partial economic evaluations conducted within the framework of eligible RCTs (i.e. cost-effectiveness analyses, cost-utility analyses, cost-benefit analyses and cost-analyses). We did not include trials of skin graft donor sites or wounds that were unable to be closed immediately because of damaged tissue (for example in severe trauma), infection or chronicity. Cross-over trials and quasi-randomised studies, e.g. treatment allocation alternate or by date of birth, were also ineligible.

 

Types of participants

We included trials involving people of any age, and in any care setting, involving the use of NPWT for surgical wounds healing by primary intention.

 

Types of interventions

The primary intervention was NPWT delivered by any mode (for example vacuum-assisted closure [(VAC® KCI, San Antonio, Texas] or simple closed-system suction drainage) delivered continuously or intermittently over any time period. The comparison interventions were any standard dressing (for example gauze) or any advanced dressing (for example hydrogels, alginates, hydrocolloids); or comparisons between different negative pressure devices.

 

Types of outcome measures

 

Primary outcomes

  • Proportion of surgical wounds healing by primary intention that completely heal (surgical wounds may include split skin grafts, full skin grafts or any primary wound closure).
  • Mortality.
  • Adverse events - including wound complications (such as wound infection, dehiscence, haematoma, seroma, fracture blisters and graft loss).

 

Secondary outcomes

  • Time to complete healing.
  • Pain (measured by any valid pain assessment instrument)
  • Quality of life (measured by any valid assessment instrument).
  • Cost (including: utility scores representing health-related quality of life; treatment costs per patient per wound; costs of health practitioner time or visits; costs of hospital stay for wound healing; procedure costs to treat adverse events, infections or complications; costs of hospital stay resulting from adverse events and complications; incremental cost per life year gained; incremental cost per quality adjusted life year (QALY) and cost-benefit ratio.

 

Search methods for identification of studies

 

Electronic searches

We searched the following electronic databases to identify reports of relevant randomised clinical trials: 

  • the Cochrane Wounds Group Specialised Register (searched 11 November 2011);
  • the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4);
  • Database of Abstracts of Reviews of Effects (The Cochrane Library 2011, Issue 4);
  • Ovid MEDLINE (2005 to October Week 4 2011);
  • Ovid MEDLINE (In-Process & Other Non-Indexed Citations 8 November 2011);
  • Ovid EMBASE (2009 to 2011 Week 44);
  • EBSCO CINAHL (1982 to 4 November 2011).

We used the following search strategy in the Cochrane Central Register of Controlled Trials (CENTRAL):

#1 MeSH descriptor Negative-Pressure Wound Therapy explode all trees
#2 MeSH descriptor Suction explode all trees
#3 MeSH descriptor Vacuum explode all trees
#4 ("negative pressure" or negative-pressure or TNP):ti,ab,kw
#5 (sub-atmospheric or subatmospheric):ti,ab,kw
#6 ((seal* NEXT surface*) or (seal* NEXT aspirat*)):ti,ab,kw
#7 (wound NEAR/3 suction*):ti,ab,kw
#8 (wound NEAR/3 drainage):ti,ab,kw
#9 ((foam NEXT suction) or (suction NEXT dressing*)):ti,ab,kw
#10 ((vacuum NEXT therapy) or (vacuum NEXT dressing*) or (vacuum NEXT seal*) or (vacuum NEXT assist*) or (vacuum NEAR closure) or (vacuum NEXT compression) or (vacuum NEXT pack*) or (vacuum NEXT drainage) or VAC):ti,ab,kw
#11 ("vacuum assisted closure technique" or VAC):ti,ab,kw
#12 (#1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 OR #11)
#13 MeSH descriptor Surgical Wound Infection explode all trees
#14 MeSH descriptor Surgical Wound Dehiscence explode all trees
#15 surg* NEAR/5 infect*:ti,ab,kw
#16 surg* NEAR/5 wound*:ti,ab,kw
#17 surg* NEAR/5 site*:ti,ab,kw
#18 surg* NEAR/5 incision*:ti,ab,kw
#19 surg* NEAR/5 dehisc*:ti,ab,kw
#20 wound* NEAR/5 dehisc*:ti,ab,kw
#21 (#13 OR #14 OR #15 OR #16 OR #17 OR #18 OR #19 OR #20)
#22 (#12 AND #21)

The search strategies for Ovid MEDLINE, Ovid EMBASE and EBSCO CINAHL can be found in Appendix 1; Appendix 2 and Appendix 3 respectively. We combined the Ovid MEDLINE search with the Cochrane Highly Sensitive Search Strategy for identifying randomised trials in MEDLINE: sensitivity- and precision-maximising version (2008 revision) (Lefebvre 2011). We combined the EMBASE and CINAHL searches with the trial filters developed by the Scottish Intercollegiate Guidelines Network (SIGN 2011).

We conducted separate searches to identify economic evaluations in the following electronic databases:

  • NHS Economic Evaluation Database (The Cochrane Library 2011, Issue 3);
  • Ovid MEDLINE (1948 to July Week 3 2011);
  • Ovid MEDLINE (In-Process & Other Non-Indexed Citations 28 July 2011);
  • Ovid EMBASE (1980 to 2011 Week 29);
  • EBSCO CINAHL (1982 to 20 July 2011)

We used economics filters developed by Centre for Reviews and Dissemination (CRD 2010) in combination with terms to describe the condition and intervention in Ovid MEDLINE, Ovid EMBASE and EBSCO CINAHL searches (see Appendix 4; Appendix 5 and Appendix 6 respectively). We did not restrict any of the above searches with respect to language, date of publication or study setting.

We searched the following clinical trials registries for details of relevant protocols and contacted the relevant research team:

  • Clinical trials.gov;
  • World Health Organization (WHO) International Clinical Trials Registry Platform;
  • Australian and New Zealand Clinical Trials Registry;
  • Current Controlled Trials.

 

Searching other resources

We checked the citation lists of papers identified by the above strategies for further reports of eligible studies. We contacted corresponding authors of identified studies and the manufacturers and distributors of devices used to deliver NPWT, such as Vacuum-Assisted Closure ((VAC® KCI, San Antonio, Texas); SNaP® Wound Care System Dressing, Spiracur Inc; Venrturi™ Avanti and Venturi™ Compact (Talley Group, England); RENASYS EZ*; and Smith & Nephew. We contacted experts in the field to ask for information about any unpublished studies.

 

Data collection and analysis

 

Selection of studies

JW, WC and MS independently reviewed titles and abstracts identified through the search process. We retrieved full reports of all potentially relevant trials for further assessment of eligibility based on the inclusion criteria. Differences of opinion were settled by consensus. There was no blinding of study authorship.

 

Data extraction and management

We extracted the following data using a pre-designed checklist:

  • methods (number eligible and randomised, adequacy of randomisation, allocation concealment, blinding, completeness of follow-up);
  • participant characteristics and exclusions;
  • type of surgery;
  • setting;
  • study dates;
  • interventions;
  • number of participants per group
  • information about ethics approval, consent and conflict of interest; and
  • outcomes

We resolved discrepancies through discussion. One review author (JW) entered data into the Review Manager software (RevMan 2011) and the other review authors checked data for accuracy. If information regarding any data was unclear, we attempted to contact study authors of the original reports to provide further details.

 

Assessment of risk of bias in included studies

Two review authors independently assessed the eligible trials (JW and KS) using the Cochrane Collaboration tool for assessing risk of bias (Higgins 2011). This tool addresses six specific domains, namely sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and other issues which may potentially bias the study (see Appendix 7 for details of the criteria on which the judgement was based). We assessed blinding and completeness of outcome data for each outcome separately. We completed a 'Risk of bias' table for each eligible study. We resolved disagreements between review authors by consensus. We contacted investigators of included trials to resolve any ambiguities. We were to have reported bias, and more generally study limitations within economic evaluations, using the checklist from the NICE Guidelines Manual (NICE 2009). We have presented assessment of risk of bias using a 'Risk of bias' summary figure, which shows all the judgements in a cross-tabulation of study by entry.

 

Measures of treatment effect

For individual trials, we extracted the numbers with an event for each treatment group and used them to calculate the risk ratio (RR) with its 95% confidence interval (CI). For statistically significant effects, we calculated number needed to treat (NNT) or number needed to harm (NNH) from the risk difference. For continuous outcomes, we extracted the mean and standard deviation (SD) and calculated the mean difference (MD) or, if the scale of measurement differed across trials, the standardised mean difference (SMD), each with its 95% CI.

 

Economic analyses

We were to have undertaken the following economic analysis but no studies provided suitable data. However the methods remain detailed here in the event that future updates of this review identify economic data.

We will present a tabled analysis of the identified economic data in accordance with current guidance on the use of economics methods in the preparation of Cochrane Reviews (Shemilt 2011). We will classify economic evaluation according to the framework in Drummond et al (Drummond 2005). We will tabulate the main characteristics and results of the identified economic evaluation studies and augment these with a narrative description. This will discuss the methods used and compare the key results of those studies.

The results of cost-effectiveness studies are likely to vary according to the particular circumstances of each study. For example, the comparator treatment, such as standard care, may differ for different types of wounds and in different settings. Our analysis will place the results of the economic studies in context and will entail a discussion of scenarios that are likely to lead to the most cost-effective use of as well as the least cost-effective use.

 

Costs

All substantial costs that are observed to differ between patients administered the NPWT and patients administered standard care are intended to be captured and reported as part of the economic analysis. 

We will report unit costs along with the currency and price year in each original study. These costs will then be converted to 2011 values by applying implicit price deflators for GDP of that currency and then converted into the currency most frequently observed in the articles reviewed using GDP Purchasing Power Parities (Shemilt 2010). This will allow readers of the review to make meaningful comparisons between costs in studies that may have been conducted in different countries and at different times.

The main costs are likely to be those associated with the NPWT itself, specialist and other practitioner costs as measured by time or number of visits, potential cost-savings from a change in the number of bed days in hospital, and costs stemming from differing rates of adverse events and complications (including procedures initiated due to the failure of wounds to heal, such as amputation). The key cost drivers will be identified from the studies included. This will enable users of the review to gain a clear understanding of the nature of resource use associated with negative pressure wound therapy.

 

Outcomes

The primary trial outcome (proportion of wounds healed) and secondary outcome (time to complete healing) are relevant to the economic analysis as they may indicate a difference in the number of hospital bed days and specialist time required and a possible improvement in quality of life for the patient.

We will examine information on the change in health-related quality of life (HR-QoL) via utilities measured by a multi-attribute utility instrument (MAUI) or other approaches (such as the time trade-off, standard gamble) where possible. Ideally these data will be reported in trials for both the group treated with NPWT and a control group receiving the comparator wound care. The utility data will need to be assessed for comparability and representativeness considering issues such as the types of wounds included, the patient populations, timing of the baseline point and follow-up collection, the MAUI used and the algorithm for scoring the MAUI. We will present discussion of the potential impact on HR-QoL attributable to the intervention as part of the analysis.

If differences can be observed in the rates of adverse events, wound infections and complications resulting from the treatment of the wound, we will discuss the economic implications as part of the economic analysis.

 

Unit of analysis issues

We did not anticipate any unit of analysis issues, cross over trials were excluded and cluster randomised trials were not expected for this type of intervention.

 

Dealing with missing data

In the event that we obtained missing data from authors, we planned an available-case analysis, based on the numbers of patients for whom outcome data were known. We also planned best-case and worst-case analyses. In the event of missing standard deviations (SD) we planned imputation from other studies or, where possible, calculation from standard errors (SE) using the formula SD = SE x √¯N , where these were available (Higgins 2011).

 

Assessment of heterogeneity

We assessed heterogeneity visually and by using the Chi2 test with significance being set at P < 0.10. In addition, we investigated the degree of heterogeneity by calculating the I2 statistic (Higgins 2011). We planned to explore potential causes of significant heterogeneity (> 30%) and use a random-effects approach to the analysis but this was not necessary.

 

Assessment of reporting biases

If sufficient studies were identified we planned to assess reporting bias using funnel plots (Higgins 2011).

 

Data synthesis

Where studies were clinically similar and outcome measurements comparable, we pooled results using a fixed-effect model and reported the pooled estimate together with its 95% CI. We conducted a narrative review of eligible studies where statistical synthesis of data from more than one study was not possible or considered not appropriate, for example if the I2 statistic was above 60%. There were no time-to-event data so estimates of hazard ratios (HR) and 95% confidence intervals (CI) were not required (Altman 2001).

 

Subgroup analysis and investigation of heterogeneity

We planned to analyse potential sources of heterogeneity using the following subgroup analyses:

  1. type of setting (community, hospital, inpatient, outpatient);
  2. type of negative pressure device (vacuum-assisted closure ((VAC® KCI, San Antonio, Texas), RENASYS systemTM (Smith & Nephew, UK), Chariker-Jeter gauze-based negative pressure systems (V1STA, Versatile-1 and EZ-Care; Smith & Nephew, Inc.);
  3. type of surgery (traumatic wounds, reconstructive procedures, other post-surgical wounds);
  4. type of comparison dressing (saline gauze, Jelonet, hydrocolloid, foam, alginate); and
  5. intermittent versus continuous negative pressure.

 

Sensitivity analysis

We planned to perform sensitivity analyses to explore the effect of the following criteria:

  1. concealment of allocation (allocation adequately concealed versus not reported or inadequate);
  2. duration of follow-up (no stated follow-up versus any follow-up; follow-up for < 4 weeks versus 4 weeks or greater); and
  3. type of randomisation (truly randomised with adequate method of generating the randomisation sequence versus not reported).

 

Results

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Description of studies

See Characteristics of included studies; Characteristics of excluded studies and Characteristics of ongoing studies.

 

Results of the search

 

Interventions search

Electronic searches yielded 356 references of which we excluded 346 because they did not meet one or more of our inclusion criteria. We retrieved the remaining 10 full-text papers for inspection. Of these, we included five papers, with results from five trials (Chio 2010; Dorafshar 2011; Howell 2011; Llanos 2006; Pachowsky 2011). A search of trial registry platforms identified 17 protocols related to NPWT. Eleven of these planned to investigate chronic wounds and were ineligible. Of the six remaining trials, five named investigators and one named the company (KCI) as the investigator. We attempted contact with the five study authors, three of whom did not respond. The investigator of one of the remaining protocols stated that the planned start date for the trial was in early 2011 (Chan 2011), we are still attempting to contact another author (Graves 2011). Regarding the company trial, KCI advised us that the trial will not be conducted. No patients were enrolled in the study, all sites were closed and all site payments reconciled. No reason was provided for terminating the study. We sent emails to all the manufacturers mentioned in our search strategy. We were advised of one animal study but identified no further human trials meeting our inclusion criteria.

 

Economic analysis search

Electronic searches yielded 115 references, none of which met our inclusion criteria.

 

Included studies

 

Types of participants

A total of 280 participants were enrolled in the five included trials (Chio 2010; Dorafshar 2011; Howell 2011; Llanos 2006; Pachowsky 2011). Participants in two trials underwent skin grafts. Chio 2010 investigated the forearm donor site among 54 patients undergoing a radial forearm free flap. Llanos 2006 enrolled 60 burns patients who had split-thickness skin grafts to their burn site. Of the remaining trials, Dorafshar 2011 recruited 87 patients with acute wounds resulting from trauma, surgery or dehiscence; Howell 2011 included 60 patients undergoing a total knee arthroplasty who were obese and at risk of infection and Pachowsky 2011 enrolled patients with closed surgical wounds after a total hip arthroplasty. Three trials were conducted in the USA (Chio 2010; Dorafshar 2011; Howell 2011) one in Chile (Llanos 2006) and one in Germany (Pachowsky 2011).

 

Types of interventions

In two trials (Chio 2010; Howell 2011), the negative pressure device, vacuum-assisted closure (VAC® KCI, San Antonio, Texas) set to -125 mmHg was compared to a standard dressing. The comparison standard dressing in the Chio 2010 trial consisted of sterile surgical foam, cut to size and wrapped in Adaptic dressing whereas wounds in the Howell 2011 trial were covered with a sterile gauze dressing that was secured with a perforated, stretchable cloth tape. Pachowsky 2011 used the PREVENA TM system (KCI, San Antonio, Texas) for the intervention treatment and a dry wound dressing as the control treatment. By contrast, Llanos 2006 used the hospital's central aspiration system at a pressure of 80 mmHg to achieve a vacuum. The comparison dressing was identical but no pressure was applied to the aspiration tubing. Dorafshar 2011 compared two negative pressure systems, (VAC® KCI, San Antonio, Texas and GSUC). The intervention dressing 'GSUC', was a locally developed system based on a gauze dressing moistened with 0.9% normal saline and sealed with an occlusive cover. A red rubber catheter was placed in the middle of the dressing and attached to continuous wall suction at 75 to 80 mm Hg.

 

Types of outcomes

Two comparisons are included; the first is negative pressure closure versus standard dressing. Incidence of adverse events was the only pre-specified primary outcome for this review reported in all studies for this comparison (Chio 2010; Howell 2011; Llanos 2006; Pachowsky 2011). Adverse events included wound blisters and deep wound infection (Howell 2011), seromas (Pachowsky 2011) and other wound complications. For example Chio 2010 defined wound complications as a combination of skin graft failure and tendon exposure. We also included "need for re-covering procedure" as a wound complication in the Llanos 2006 trial. Outcomes were measured in the Chio 2010 trial two weeks after surgery, in the Llanos 2006 study, outcome data were measured when wounds were uncovered, four days post surgery, Howell 2011 followed patients up for 12 months and in the Pachowsky 2011 trial, ultrasound examinations were conducted on day five and day 10 post surgery. The second comparison was one negative pressure closure versus another negative pressure closure (GSUC versus VAC® KCI, San Antonio, Texas). One trial was included in this comparison (Dorafshar 2011). Outcomes of interest to this review included adverse events, pain and cost.

Other outcomes, such as median graft loss, percentage of graft loss, time from grafting to hospital discharge and rates of change in surface area and wound volume, were reported by trialists, but these data were not included in our pre-specified primary or secondary outcomes.

 

Excluded studies

Five trials were excluded (Hu 2009; Johannesson 2008; Kim 2007; Moues 2004; Moues 2007). The intervention dressing in one trial was not a negative pressure device (Johannesson 2008); one was not a randomised controlled trial (Kim 2007); and three did not include acute wounds (Hu 2009; Moues 2004; Moues 2007). Two further trials included both chronic and acute wounds but results were not presented separately and, despite attempts to contact authors, no further information could be obtained (Braakenburg 2006; Moisidis 2004), these studies are currently classified as awaiting assessment as we continue in our efforts to obtain further information.

 

Risk of bias in included studies

See Figure 1 for a risk of bias summary.

 FigureFigure 1. Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

 

Allocation

 

Sequence generation

Three of the five investigators described some form of process to generate the random allocation list. A computer-based random number generator was used in two trials (Chio 2010; Llanos 2006) and a web-based random number generator in the third (Dorafshar 2011). In the two other studies (Howell 2011; Pachowsky 2011) how the sequence was generated was not specified.

 

Allocation concealment

The method used for allocation concealment was unclear in the Chio 2010; Dorafshar 2011 and Howell 2011 trials. In the Dorafshar 2011 study, participants were allocated to their group "by drawing a previously prepared card", however, it was unclear if cards were concealed until the point of randomisation. "Blinded envelopes" were used in the Howell 2011 trial, we have assumed that 'blinded' indicated opaque however, we have been unable to confirm this with the author. Allocation in the Llanos 2006 study was not concealed since the theatre nurse allocated patients from a randomised list and the next allocation would have been predictable.

 

Blinding

 

Participants and personnel

The appearance of dressings was dissimilar in the Chio 2010; Dorafshar 2011; Howell 2011 and Pachowsky 2011 trials, so blinding was impossible. Dressings were identical in the Llanos 2006 trial and both groups had tubing attached to a suction apparatus. However, patients and staff would almost certainly have been aware if suction was activated.

 

Outcome assessment

Outcome measurement was not blinded in two of the trials (Chio 2010; Dorafshar 2011) and in the Howell 2011 trial it was unclear if whether outcome assessment was blinded. Ultrasound was used to assess outcomes in the Pachowsky 2011 trial but whether the ultrasonographer was blind to allocation was not stated. However, in the Llanos 2006 study, assessment was by photographs and the person assessing the photographs was "masked to which intervention the patient had received".

 

Incomplete outcome data

All participants were included in the analyses of four trials (Dorafshar 2011; Howell 2011; Llanos 2006; Pachowsky 2011). Four (7.4%) participants were unavailable for follow-up in the Chio 2010 trial, all of whom were assigned to the negative pressure group therefore Chio 2010 was deemed to be at high risk of attrition bias.

 

Selective reporting

All of each study's pre-specified outcomes, as defined in the papers, were reported in the results. No published protocol was available for four trials (Chio 2010; Howell 2011; Llanos 2006; Pachowsky 2011). In the Dorafshar 2011 trial, measures reflected the pre-defined outcomes listed in the published protocol (NCT00724750). However, the study began in 2006 but the protocol was first published in July 2008, so there is a potential for study characteristics to have changed before or during the study.

 

Other potential sources of bias

A manufacturer funded the Howell 2011 trial, which also contained unequal numbers in each arm of the trial. This trial was stopped early due to an unacceptably higher rate of blisters among patients in the negative pressure group. The Pachowsky 2011 trial was also manufacturer funded and one of the authors received conference funding from the manufacturer of the trial intervention.

 

Effects of interventions

 

Comparison 1: Negative pressure wound therapy versus standard dressing (four trials, 189 participants)

 

Primary

 
Proportion of surgical wounds healing by primary intention that completely heal

Results for this outcome were not provided by either Chio 2010; Llanos 2006 or Pachowsky 2011. All of the wounds in the Howell 2011 trial healed.

 
Mortality

Although not directly reported, results indicate that no participant died during any of the trials (Chio 2010; Howell 2011; Llanos 2006; Pachowsky 2011).

 
Adverse events

Four trials of 189 participants reported data for this outcome (Chio 2010; Howell 2011; Llanos 2006; Pachowsky 2011). Adverse events were reported in two trials involving skin loss following grafting and were pooled Chio 2010; Llanos 2006). There was no statistically significant difference between groups for this outcome (NPWT 13/53 24.5%; standard dressing 24/57 42.1%); the RR was 0.61 (95% CI 0.33 to 1.13)  Analysis 1.1. In the Howell 2011 trial, fracture blisters and deep wound infections were included as adverse events. Significantly more fracture blisters were observed in the NPWT group (15/24; 62.5%) when compared with the standard dressing group (3/36;8.3%); RR 7.50 (95% CI 2.43 to 23.14; p = 0.0005)  Analysis 1.2. In the same study, one deep wound infection occurred in each group Howell 2011. The adverse events reported in the Pachowsky 2011 trial were seromas but there was no significant difference between the groups. In the NPWT group 4/9 (44.9%) participants developed a seroma compared with 9/10 (90%) participants in the standard dressing group; RR 0.09 (95% CI 0.01 to 1.03)  Analysis 1.3 (p = >0.05).

 

Secondary

 
Time to complete healing

In the Howell 2011 trial, there was no reported difference in time to wound closure between groups (negative pressure 4.3 days; static pressure 4.1 days). Neither of the other three trials provided data for this outcome (Chio 2010; Llanos 2006; Pachowsky 2011).

 
Pain

Results for this outcome were not provided by any of the authors (Chio 2010; Howell 2011; Llanos 2006; Pachowsky 2011).

 
Quality of life

None of the included studies provided measures for this outcome.

Cost

None of the included studies provided measures for this outcome.

 

Comparison 2: One negative pressure closure method (GSUC) versus another negative pressure closure method (VAC® KCI, San Antonio, Texas) (one trial 87 participants)

 

Primary

 
Proportion of surgical wounds healing by primary intention that completely heal

There were no data for this outcome.

 
Mortality

Although not directly reported, results at follow-up indicate that none of the participants died during the study.

 
Adverse events

In their study of 87 participants, Dorafshar 2011 reported a higher adverse rate in the VAC® therapy group, all of these were haematomas (VAC® 3/42; GSUC 0/45); the odds ratio (OR) was 0.13 (95% CI 0.01 to 2.51); P = 0.18) ( Analysis 2.1).

 

Secondary

 
Time to complete healing

There were no data for this outcome.

 
Pain

Pain before, during and after dressing changes was reported to be lower in the GSUC group when compared to the VAC® group (P = 0.02) (Dorafshar 2011).

 
Wound complications

 
Quality of life

Quality of life was not measured in this trial.

 
Cost

One within-trial cost analysis was undertaken by Dorafshar 2011, who reported that the mean cost of supply equipment for VAC® therapy was USD 96.51/day compared to USD 4.22/day for the GSUC therapy (P = 0.01). The daily labour costs to change the dressings were USD 21.18/day for GSUC versus USD 25.55/day for VAC® (P = 0.11). Overall, there was a greater than fourfold increase in costs in the VAC® group.

 

Discussion

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Summary of main results

 

Wound healing

This systematic review examined the evidence from randomised controlled trials (RCTs) that focused on the effectiveness of negative pressure wound therapy for acute surgical wounds. Evidence is limited, with only five small trials of 280 participants meeting the inclusion criteria. Although negative pressure wound therapy (NPWT) is being widely used and is supported for use for a range of surgical applications (Krug 2011) there is no evidence to support or refute the effectiveness of NPWT to improve healing rates or to reduce time to complete healing from this review. Our pre-defined primary outcome, 'the proportion of wounds that completely heal', may be a useful measure for chronic wounds, where NPWT is widely used. However, it has become clear to us that this outcome is not appropriate for surgery that is expected to heal by primary intention; most clean surgical wounds will completely heal in a relatively short time. Moreover, determining when a surgical incision is 'completely healed' is difficult. Consequently, wound healing should not be included as a primary outcome for future updates.

 

Adverse events

Trials included in this review included orthopaedic surgery, skin grafts and general surgery. With the exception of two trials involving skin graft survival, clinical heterogeneity and dissimilar outcomes prevented pooling results. Two trials were suggestive of a benefit of NPWT for skin graft survival (Chio 2010; Howell 2011) and one for the prevention of seromas (Pachowsky 2011) but all of these trials were at unclear or high risk of bias, reducing confidence in the results. Conversely, increased harm through the use of NPWT was shown in one trial (Howell 2011). This was the formation of skin blisters around the edge of the NPWT dressing. In this trial, the dressing-associated blister rate was 63% in the NPWT group (Howell 2011), which compares poorly with rates between 2.4% to 26% in other recent trials where modern wound dressings have been used for postoperative orthopaedic wounds (Abuzakuk 2006; Koval 2007; Ravenscroft 2006; Ravnskog 2011) and was the reason for early termination of the trial. It is unclear why skin blisters occur following orthopedic surgery but may be due postoperative swelling, leading to sheer or friction when the securing tape is stretched (Ravenscroft 2006).

It is also unclear which system should be used to deliver the therapy. Although there is substantial literature related to wound healing using the vacuum-assisted closure (VAC® KCI, San Antonio, Texas) system (Morykwas 1997), our review failed to support the use of a commercial device for acute wounds. The systems are very expensive and our results suggest that alternative, cheaper methods may be as effective. For example, in one trial where the VAC® system was compared to a standard dressing, there was a 10% reduction in wound complications in the VAC® group (Chio 2010). However, in a similar study, where negative pressure was achieved using the hospital's aspiration system, the wound complication rate in the negative pressure group was 23% less than in the standard dressing group (Llanos 2006). Although the difference was not statistically significant in either trial, the results may be reassuring to those who cannot afford the expense of hiring the equipment required for VAC® and similar commercial systems. Additional evidence for the safety of a hospital-devised system was provided in the most recent trial where the VAC® system was directly compared with a method based on a sealed gauze dressing and the hospital's wall suction (Dorafshar 2011). In that study, there was no difference in the wound complication rate between the two groups.

 

Cost

When compared to a commercial system of delivering NPWT, equipment costs were four times lower when a hospital-based system was used (USD 25.40/day compared to USD 110.06/day). This was due entirely to higher equipment cost for the commercial product; the cost for labour to change the dressings was similar (Dorafshar 2011). Although these results are from only one trial, until equipment costs from commercial manufactures are substantially reduced, additional studies are unlikely to change this finding. In attempts to find ways around these costs, innovative attempts to develop hospital-based systems are increasing (Mody 2008; Perez 2010; Rozen 2008; Shalom 2008).

 

Pain

In one study pain levels during and after dressing changes were significantly lower in the hospital-based negative pressure group (Dorafshar 2011). However, the hospital-based device used continuous suction at 75 to 80 mm Hg, whereas the VAC® system was set between 75 to 125 mm Hg, which may account for the reported difference in perceived pain.

 

Overall completeness and applicability of evidence

Indications for the use of NPWT in closed surgery are broadening (DeCarbo 2010; Pachowsky 2011) with a range of new systems on the market, including those designed for use on clean, closed wounds (Allen 2011). However, studies eligible for inclusion in our review represented a relatively narrow focus; there were two skin graft trials, one trial that included patients with acute wounds from trauma or surgery and two others that recruited patients undergoing a planned total knee or hip arthroplasty. The largest trial enrolled 87 patients. Negative pressure levels varied between trials and between device types, with hospital aspiration systems generally using a lower pressure than the VAC®) system. Whether different pressures produce different outcomes is unclear from our results but animal studies indicate that performance is similar across the range of pressures used in the trials we included (Morykwas 2001). Another limitation was a variation in the follow-up times, which ranged from the fourth postoperative day (Llanos 2006) to 12 months post surgery (Howell 2011). Finally, included trials were geographically limited; three were conducted in North America, one in South America and one in Germany, further restricting the external validity of results. In light of these limitations, there remains uncertainty about whether NPWT should be used at all for closed surgical wounds, unless there are reasons to believe that the wound may be difficult to heal. There are also important questions about the use of NPWT for orthopaedic surgery; the one trial in this category was terminated early because of high blister rates.

 

Quality of the evidence

Limitations in study design and implementation

Risk of bias was assessed according to six domains: sequence generation; allocation concealment; blinding; selective outcome reporting, incomplete follow-up and other potential biases. Our assessments of the risk of bias for a number of these domains in all of the included studies showed limitations in study design and implementation, these have been reported elsewhere in the review Figure 1. Of particular concern, in a study where blinding of the intervention is difficult or impossible, was uncertainty about allocation concealment and outcome assessment blinding. Accordingly, the quality of the evidence was considered unclear for all of the outcomes.

Indirectness of evidence

The review was limited by a lack of conformity; in both the experimental and the control intervention. For example the negative pressure device varied between studies as did the control dressing. Consequently, the evidence was restricted to indirect comparisons between these varied interventions. Additionally, the review aimed to assess NPWT for acute surgical wounds but the type of surgeries were limited. As a result, the evidence may be regarded as indirect for other types of surgery. Finally, direct evidence of the effect of the intervention on wound infection or dehiscence, arguably the most important adverse outcomes of surgery, was reported in only one study. Taken together, these limitations restrict confident decision making in regards to the use of NPWT for acute wounds.

Unexplained heterogeneity or inconsistency of results

The only outcome which could be pooled was an assessment of skin graft survival. Consequently, we were unable to evaluate the effects of the intervention across studies.

Imprecision of results

In the only pooled outcome, confidence intervals were quite narrow but only two small studies of skin graft failure were included  Analysis 1.1. Of the other, single study outcomes, only one showed evidence of effect. In this trial, where NPWT was more likely to cause fracture blisters than the standard dressing, we have included the confidence intervals to indicate the high level of uncertainty around the effect size  Analysis 1.2.  Further research is therefore very likely to have an important impact on the confidence of the estimate of effect for all of the measured outcomes and is likely to change the estimate.

Publication bias

We feel confident that our comprehensive electronic searches identified all existing, published randomised controlled trials addressing the review question, helping to limit bias in the review process. However, most of the trials identified through a search of the Clinical Trial Registries have not been published and we were unable to track down any information about them. Moreover, the scant contribution of the five included trials, in the face of such wide use of NPWT, is unusual. These two factors may or may not indicate publication bias.

 

Potential biases in the review process

Clearly described procedures were followed to prevent potential bias in the review process. A careful literature search was conducted and the methods we used were transparent and reproducible. None of the authors has any conflict of interest. It is possible that trials published in journals that were outside of our search strategy may have been missed.

 

Agreements and disagreements with other studies or reviews

Our results are consistent with the most recent evidence-based recommendations for the use of NPWT, which cover a range of applications, including NPWT for acute wounds (Krug 2011). The systematic review by Ubbink 2008 was published before three of our included trials were undertaken; their review also included an earlier trial that we had excluded from our review (Moisidis 2004) so results are not comparable. However, our findings are in agreement with other non-randomised studies that show that NPWT may reduce wound complications (Blume 2010; DeCarbo 2010; Kim 2007). Other randomised (Hu 2009) and non-randomised studies have also shown a marked cost benefit when non-commercial applications were compared with commercial products (Rozen 2008; Shalom 2008). In one of these studies, a net saving per patient was USD 2603 (Rozen 2008).

 

Authors' conclusions

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

 

Implications for practice

Evidence for the effectiveness of negative pressure wound therapy (NPWT) for complete healing of acute wounds remains unclear, as does the effect of NPWT on time to complete healing. Rates of graft loss may lower when NPWT is used, but hospital-based products are as effective in this area as commercial applications. There are clear cost benefits when non-commercial systems are used to create the negative pressure required for wound therapy, with no reduction in clinical outcome. Pain levels are also rated lower when hospital systems are compared with their commercial counterparts. The high incidence of blisters occurring when NPWT is used following orthopaedic surgery suggests that the therapy should be limited until safety in this population is established.

 
Implications for research

There is an urgent need for suitably powered, high-quality trials to evaluate the effectiveness of the newer NPWT products, which are designed for use on clean, closed surgical incisions. Such trials should focus initially on wounds that may be difficult to heal, such as sternal wounds or surgeries on obese patients. Given the large cost differences between products, further trials comparing different types of NPWT are also justified. Full economic evaluations, including those associated with the NPWT itself, specialist and other practitioner costs as measured by time or number of visits, potential cost-savings from a change in the number of bed days in hospital, and costs stemming from differing rates of adverse events and complications (including procedures initiated due to the failure of wounds to heal, such as amputation) need to be included. This will enable users of any future review to gain a clear understanding of the nature of resource use associated with negative pressure wound therapy. To facilitate assessment, future trials that combine different types of conditions (acute, sub-acute and chronic) should present results of each condition group separately. It may also be useful to test NPWT at various pressures.

 

Acknowledgements

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

The authors would like to thank the peer referees: Wounds Group editors - Kurinchi Gurusamy, Dirk Ubbink, Gill Worthy and referees - Fausto Biancari, Susanne Cunliffe, Patricia Davies, Jo Dumville, Ian Schemilt and copy editor Jenny Bellorini.

The NHMRC has provided funding for this review from its Centre of Research Excellence Scheme, which funds one or more of the authors.

 

Data and analyses

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
Download statistical data

 
Comparison 1. Negative pressure versus standard dressing

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Adverse events2110Risk Ratio (M-H, Random, 95% CI)0.61 [0.33, 1.13]

 2 Fracture blisters1Risk Ratio (M-H, Fixed, 95% CI)Totals not selected

 3 Seroma1Odds Ratio (M-H, Fixed, 95% CI)Totals not selected

 
Comparison 2. Negative pressure GSUC versus negative pressure VAC

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Adverse events187Risk Ratio (M-H, Fixed, 95% CI)0.13 [0.01, 2.51]

 

Appendices

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Appendix 1. Ovid MEDLINE effectiveness search strategy

1 exp Negative-Pressure Wound Therapy/
2 exp Suction/
3 exp Vacuum/
4 (negative pressure or negative-pressure or TNP).tw.
5 (sub-atmospheric or subatmospheric).tw.
6 ((seal* adj surface*) or (seal* adj aspirat*)).tw.
7 (wound adj2 suction*).tw.
8 (wound adj5 drainage).tw.
9 ((foam adj suction) or (suction adj dressing*)).tw.
10 (vacuum assisted closure technique or VAC).tw.
11 ((vacuum adj therapy) or (vacuum adj dressing*) or (vacuum adj seal*) or (vacuum adj closure) or (vacuum adj compression) or (vacuum adj pack*) or (vacuum adj drainage) or (suction* adj drainage)).tw.
12 or/1-11
13 exp Surgical Wound Infection/
14 exp Surgical Wound Dehiscence/
15 (surg* adj5 infect*).tw.
16 (surg* adj5 wound*).tw.
17 (surg* adj5 site*).tw.
18 (surg* adj5 incision*).tw.
19 (surg* adj5 dehisc*).tw.
20 (wound* adj5 dehisc*).tw.
21 (wound* adj5 dehisc*).tw.
22 or/13-21
23 12 and 22
24 randomized controlled trial.pt.
25 controlled clinical trial.pt.
26 randomized.ab.
27 placebo.ab.
28 clinical trials as topic.sh.
29 randomly.ab.
30 trial.ti.
31 or/24-30
32 (animals not (humans and animals)).sh.
33 31 not 32
34 23 and 33
35 (2005* or 2006* or 2007* or 2008* or 2009* or 2010*).ed.
36 34 and 35

 

Appendix 2. Ovid EMBASE effectiveness search strategy

1 exp suction drainage/
2 exp vacuum assisted closure/
3 (negative pressure or negative-pressure or TNP).tw.
4 (sub-atmospheric or subatmospheric).tw.
5 ((seal* adj surface*) or (seal* adj aspirat*)).tw.
6 (wound adj2 suction*).tw.
7 (wound adj5 drainage).tw.
8 ((foam adj suction) or (suction adj dressing*)).tw.
9 (vacuum assisted closure technique or VAC).tw.
10 ((vacuum adj therapy) or (vacuum adj dressing*) or (vacuum adj seal*) or (vacuum adj closure) or (vacuum adj compression) or (vacuum adj pack*) or (vacuum adj drainage) or (suction* adj drainage)).tw.
11 or/1-10
12 exp Surgical Wound Infection/
13 exp Surgical Wound Dehiscence/
14 (surg* adj5 infection*).tw.
15 (surg* adj5 wound*).tw.
16 (surg* adj5 site*).tw.
17 (surg* adj5 incision*).tw.
18 (surg* adj5 dehisc*).tw.
19 (wound* adj5 dehisc*).tw.
20 or/12-19
21 11 and 20
22 Clinical trial/
23 Randomized controlled trials/
24 Random Allocation/
25 Single-Blind Method/
26 Double-Blind Method/
27 Cross-Over Studies/
28 Placebos/
29 Randomi?ed controlled trial$.tw.
30 RCT.tw.
31 Random allocation.tw.
32 Randomly allocated.tw.
33 Allocated randomly.tw.
34 (allocated adj2 random).tw.
35 Single blind$.tw.
36 Double blind$.tw.
37 ((treble or triple) adj blind$).tw.
38 Placebo$.tw.
39 Prospective Studies/
40 or/22-39
41 Case study/
42 Case report.tw.
43 Abstract report/ or letter/
44 or/41-43
45 40 not 44
46 animal/
47 human/
48 46 not 47
49 45 not 48
50 21 and 49
51 (2009* or 2010* or 2011*).em.
52 50 and 51

 

Appendix 3. EBSCO CINAHL effectiveness search strategy

S22 S12 and S21
S21 S13 or S14 or S15 or S16 or S17 or S18 or S19 or S20
S20 TI wound* N5 dehisc* or AB wound* N5 dehisc*
S19 TI surg* N5 dehisc* or AB surg* N5 dehisc*
S18 TI surg* N5 incision* or AB surg* N5 incision*
S17 TI surg* N5 site* or AB surg* N5 site*
S16 TI surg* N5 wound* or AB surg* N5 wound*
S15 TI surg* N5 infection* or AB surg* N5 infection*
S14 (MH "Surgical Wound Dehiscence")
S13 (MH "Surgical Wound Infection")
S12 S1 or S2 or S3 or S4 or S5 or S6 or S7 or S8 or S9 or S10 or S11
S11 TI ( foam suction or suction dressing* or suction drainage ) or AB ( foam suction or suction dressing* or suction drainage )
S10 AB vacuum therapy or vacuum dressing* or vacuum seal* or vacuum closure or vacuum compression or vacuum pack or vacuum drainage
S9 TI vacuum therapy or vacuum dressing* or vacuum seal* or vacuum closure or vacuum compression or vacuum pack or vacuum drainage
S8 TI wound N5 drainage or AB wound N5 drainage
S7 TI wound N5 suction* or AB wound N5 suction*
S6 TI ( seal* N1 surface* or seal* N1 aspirat* ) or AB ( seal* N1 surface* or seal* N1 aspirat* )
S5 TI ( sub-atmospheric or subatmospheric ) or AB ( sub-atmospheric or subatmospheric )
S4 TI ( negative pressure or negative-pressure or TNP ) or AB ( negative pressure or negative-pressure or TNP )
S3 (MH "Negative Pressure Wound Therapy")
S2 (MH "Vacuum")
S1 (MH "Suction+")

 

Appendix 4. Ovid MEDLINE economics search strategy

1 exp Negative-Pressure Wound Therapy/
2 exp Suction/
3 exp Vacuum/
4 (negative pressure or negative-pressure or TNP).tw.
5 (sub-atmospheric or subatmospheric).tw.
6 ((seal* adj surface*) or (seal* adj aspirat*)).tw.
7 (wound adj2 suction*).tw.
8 (wound adj5 drainage).tw.
9 ((foam adj suction) or (suction adj dressing*)).tw.
10 (vacuum assisted closure technique or VAC).tw.
11 ((vacuum adj therapy) or (vacuum adj dressing*) or (vacuum adj seal*) or (vacuum adj closure) or (vacuum adj compression) or (vacuum adj pack*) or (vacuum adj drainage) or (suction* adj drainage)).tw.
12 or/1-11
13 exp Surgical Wound Infection/
14 exp Surgical Wound Dehiscence/
15 (surg* adj5 infect*).tw.
16 (surg* adj5 wound*).tw.
17 (surg* adj5 site*).tw.
18 (surg* adj5 incision*).tw.
19 (surg* adj5 dehisc*).tw.
20 (wound* adj5 dehisc*).tw.
21 (wound* adj5 dehisc*).tw.
22 or/13-21
23 12 and 22
24 economics/
25 exp "costs and cost analysis"/
26 economics, dental/
27 exp "economics, hospital"/
28 economics, medical/
29 economics, nursing/
30 economics, pharmaceutical/
31 (economic* or cost or costs or costly or costing or price or prices or pricing or pharmacoeconomic*).ti,ab.
32 (expenditure* not energy).ti,ab.
33 value for money.ti,ab.
34 budget*.ti,ab.
35 or/24-34
36 ((energy or oxygen) adj cost).ti,ab.
37 (metabolic adj cost).ti,ab.
38 ((energy or oxygen) adj expenditure).ti,ab.
39 or/36-38
40 35 not 39
41 letter.pt.
42 editorial.pt.
43 historical article.pt.
44 or/41-43
45 40 not 44
46 Animals/
47 Humans/
48 46 not (46 and 47)
49 45 not 48
50 23 and 49

 

Appendix 5. Ovid EMBASE economics search strategy

1 exp suction drainage/
2 exp vacuum assisted closure/
3 (negative pressure or negative-pressure or TNP).tw.
4 (sub-atmospheric or subatmospheric).tw.
5 ((seal* adj surface*) or (seal* adj aspirat*)).tw.
6 (wound adj2 suction*).tw.
7 (wound adj5 drainage).tw.
8 ((foam adj suction) or (suction adj dressing*)).tw.
9 (vacuum assisted closure technique or VAC).tw.
10 ((vacuum adj therapy) or (vacuum adj dressing*) or (vacuum adj seal*) or (vacuum adj closure) or (vacuum adj compression) or (vacuum adj pack*) or (vacuum adj drainage) or (suction* adj drainage)).tw.
11 or/1-10
12 exp Surgical Wound Infection/
13 exp Surgical Wound Dehiscence/
14 (surg* adj5 infection*).tw.
15 (surg* adj5 wound*).tw.
16 (surg* adj5 site*).tw.
17 (surg* adj5 incision*).tw.
18 (surg* adj5 dehisc*).tw.
19 (wound* adj5 dehisc*).tw.
20 or/12-19
21 11 and 20
22 health-economics/
23 exp economic-evaluation/
24 exp health-care-cost/
25 exp pharmacoeconomics/
26 or/22-25
27 (econom* or cost or costs or costly or costing or price or prices or pricing or pharmacoeconomic*).ti,ab.
28 (expenditure* not energy).ti,ab.
29 (value adj2 money).ti,ab.
30 budget*.ti,ab.
31 or/27-30
32 26 or 31
33 letter.pt.
34 editorial.pt.
35 note.pt.
36 or/33-35
37 32 not 36
38 (metabolic adj cost).ti,ab.
39 ((energy or oxygen) adj cost).ti,ab.
40 ((energy or oxygen) adj expenditure).ti,ab.
41 or/38-40
42 37 not 41
43 exp animal/
44 exp animal-experiment/
45 nonhuman/
46 (rat or rats or mouse or mice or hamster or hamsters or animal or animals or dog or dogs or cat or cats or bovine or sheep).ti,ab,sh.
47 or/43-46
48 exp human/
49 exp human-experiment/
50 or/48-49
51 47 not (47 and 50)
52 42 not 51
53 21 and 52

 

Appendix 6. EBSCO CINAHL economics search strategy

S45 S22 and S44
S44 S40 NOT S43
S43 S19 NOT (S19 AND S42)
S42 MH "Human"
S41 MH "Animal Studies"
S40 S35 NOT S39
S39 S36 or S37 or S38
S38 PT commentary
S37 PT letter
S36 PT editorial
S35 S33 OR S34
S34 TI (cost or costs or economic* or pharmacoeconomic* or price* or pricing*) OR AB (cost or costs or economic* or pharmacoeconomic* or price* or pricing*)
S33 S29 OR S32
S32 S30 OR S31
S31 MH "Health Resource Utilization"
S30 MH "Health Resource Allocation"
S29 S23 NOT S28
S28 S24 or S25 or S26 or S27
S27 MH "Business+"
S26 MH "Financing, Organized+"
S25 MH "Financial Support+"
S24 MH "Financial Management+"
S23 MH "Economics+"
S22 S12 and S21
S21 S13 or S14 or S15 or S16 or S17 or S18 or S19 or S20
S20 TI wound* N5 dehisc* or AB wound* N5 dehisc*
S19 TI surg* N5 dehisc* or AB surg* N5 dehisc*
S18 TI surg* N5 incision* or AB surg* N5 incision*
S17 TI surg* N5 site* or AB surg* N5 site*
S16 TI surg* N5 wound* or AB surg* N5 wound*
S15 TI surg* N5 infection* or AB surg* N5 infection*
S14 (MH "Surgical Wound Dehiscence")
S13 (MH "Surgical Wound Infection")
S12 S1 or S2 or S3 or S4 or S5 or S6 or S7 or S8 or S9 or S10 or S11
S11 TI foam suction or suction dressing* or suction drainage or AB foam suction or suction dressing* or suction drainage
S10 AB vacuum therapy or vacuum dressing* or vacuum seal* or vacuum closure or vacuum compression or vacuum pack or vacuum drainage
S9 TI vacuum therapy or vacuum dressing* or vacuum seal* or vacuum closure or vacuum compression or vacuum pack or vacuum drainage
S8 TI wound N5 drainage or AB wound N5 drainage
S7 TI wound N5 suction* or AB wound N5 suction*
S6 TI seal* N1 surface* or seal* N1 aspirat* or AB seal* N1 surface* or seal* N1 aspirat*
S5 TI sub-atmospheric or subatmospheric or AB sub-atmospheric or subatmospheric
S4 TI negative pressure or negative-pressure or TNP or AB negative pressure or negative-pressure or TNP
S3 (MH "Negative Pressure Wound Therapy")
S2 (MH "Vacuum")
S1 (MH "Suction+")

 

Appendix 7. Risk of bias criteria

 

1.  Was the allocation sequence randomly generated?

 
Low risk of bias

The investigators describe a random component in the sequence generation process such as: referring to a random number table; using a computer random number generator; coin tossing; shuffling cards or envelopes; throwing dice; drawing of lots.

 
High risk of bias

The investigators describe a non-random component in the sequence generation process. Usually, the description would involve some systematic, non-random approach, for example: sequence generated by odd or even date of birth; sequence generated by some rule based on date (or day) of admission; sequence generated by some rule based on hospital or clinic record number.

 
Unclear

Insufficient information about the sequence generation process to permit judgement of low or high risk of bias.

 

2.  Was the treatment allocation adequately concealed?

 
Low risk of bias

Participants and investigators enrolling participants could not foresee assignment because one of the following, or an equivalent method, was used to conceal allocation: central allocation (including telephone, web-based and pharmacy-controlled randomisation); sequentially numbered drug containers of identical appearance; sequentially numbered, opaque, sealed envelopes.

 
High risk of bias

Participants or investigators enrolling participants could possibly foresee assignments and thus introduce selection bias, such as allocation based on: using an open random allocation schedule (e.g. a list of random numbers); assignment envelopes were used without appropriate safeguards (e.g. if envelopes were unsealed or non­opaque or not sequentially numbered); alternation or rotation; date of birth; case record number; any other explicitly unconcealed procedure.

 
Unclear

Insufficient information to permit judgement of low or high risk of bias. This is usually the case if the method of concealment is not described or not described in sufficient detail to allow a definite judgement, for example if the use of assignment envelopes is described, but it remains unclear whether envelopes were sequentially numbered, opaque and sealed.

 

3.  Blinding - was knowledge of the allocated interventions adequately prevented during the study?

 
Low risk of bias

Any one of the following.

  • No blinding, but the review authors judge that the outcome and the outcome measurement are not likely to be influenced by lack of blinding.
  • Blinding of participants and key study personnel ensured, and unlikely that the blinding could have been broken.
  • Either participants or some key study personnel were not blinded, but outcome assessment was blinded and the non-blinding of others unlikely to introduce bias.

 
High risk of bias

Any one of the following.

  • No blinding or incomplete blinding, and the outcome or outcome measurement is likely to be influenced by lack of blinding.
  • Blinding of key study participants and personnel attempted, but likely that the blinding could have been broken.
  • Either participants or some key study personnel were not blinded, and the non-blinding of others likely to introduce bias.

 
Unclear

Any one of the following.

  • Insufficient information to permit judgement of low or high risk of bias.
  • The study did not address this outcome.

 

4.  Were incomplete outcome data adequately addressed?

 
Low risk of bias

Any one of the following.

  • No missing outcome data.
  • Reasons for missing outcome data unlikely to be related to true outcome (for survival data, censoring unlikely to be introducing bias).
  • Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups.
  • For dichotomous outcome data, the proportion of missing outcomes compared with observed event risk not enough to have a clinically relevant impact on the intervention effect estimate.
  • For continuous outcome data, plausible effect size (difference in means or standardised difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size.
  • Missing data have been imputed using appropriate methods.

 
High risk of bias

Any one of the following.

  • Reason for missing outcome data likely to be related to true outcome, with either imbalance in numbers or reasons for missing data across intervention groups.
  • For dichotomous outcome data, the proportion of missing outcomes compared with observed event risk enough to induce clinically relevant bias in intervention effect estimate.
  • For continuous outcome data, plausible effect size (difference in means or standardised difference in means) among missing outcomes enough to induce clinically relevant bias in observed effect size.
  • ‘As-treated’ analysis done with substantial departure of the intervention received from that assigned at randomisation.
  • Potentially inappropriate application of simple imputation.

 
Unclear

Any one of the following.

  • Insufficient reporting of attrition/exclusions to permit judgement of low or high risk of bias (e.g. number randomised not stated, no reasons for missing data provided).
  • The study did not address this outcome.

 

5.  Are reports of the study free of suggestion of selective outcome reporting?

 
Low risk of bias

Any of the following.

  • The study protocol is available and all of the study’s pre-specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre-specified way.
  • The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre-specified (convincing text of this nature may be uncommon)

 
High risk of bias

Any one of the following.

  • Not all of the study’s pre-specified primary outcomes have been reported.
  • One or more primary outcomes is reported using measurements, analysis methods or subsets of the data (e.g. subscales) that were not pre-specified.
  • One or more reported primary outcomes were not pre-specified (unless clear justification for their reporting is provided, such as an unexpected adverse effect).
  • One or more outcomes of interest in the review are reported incompletely so that they cannot be entered in a meta-analysis.
  • The study report fails to include results for a key outcome that would be expected to have been reported for such a study.

 
Unclear

Insufficient information to permit judgement of low or high risk of bias. It is likely that the majority of studies will fall into this category.

 

6.  Other sources of potential bias

 
Low risk of bias

The study appears to be free of other sources of bias.

 
High risk of bias

There is at least one important risk of bias. For example, the study:

  • had a potential source of bias related to the specific study design used; or
  • had extreme baseline imbalance; or
  • has been claimed to have been fraudulent; or
  • had some other problem.

 
Unclear

There may be a risk of bias, but there is either:

  • insufficient information to assess whether an important risk of bias exists; or
  • insufficient rationale or evidence that an identified problem will introduce bias.

 

 

Appendix 8. Glossary of terms


TermDescription

DehiscenceWound dehiscence is a complication of surgery in which a wound breaks open along the line of the surgical incision.

GSUCGSUC is a system of negative pressure wound therapy. It is based on a gauze dressing moistened with 0.9% normal saline into which a red rubber catheter is inserted. The dressing is then sealed with an occlusive cover and continuous wall suction at 75 to 80 mm Hg is applied.

Negative pressure wound therapy (NPWT)NPWT is based on a closed sealed system that produces negative pressure to the wound surface. The wound is covered or packed with an open-cell foam or
gauze dressing and sealed with an occlusive drape. Intermittent or continuous suction is maintained by connecting suction tubes from the wound dressing to a vacuum pump and liquid waste collector. Standard negative pressure rates range between 50 and 125 mm Hg (Ubbink 2008; Vikatmaa 2008).

Risk ratio (RR)The risk ratio or relative risk (RR) is the probability that a member of a group who is exposed to an intervention will develop an event relative to the probability that a member of an unexposed group will develop that same event.



 

What's new

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

Last assessed as up-to-date: 18 November 2011.


DateEventDescription

13 November 2013AmendedAcknowledgement added to the funders



 

History

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

Protocol first published: Issue 8, 2011
Review first published: Issue 4, 2012


DateEventDescription

16 May 2012Amendedadjustments to text



 

Contributions of authors

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Contributions of editorial base:

Nicky Cullum: edited the protocol; advised on methodology, interpretation and protocol content. Approved the final review prior to submission.
Sally Bell-Syer: co-ordinated the editorial process. Advised on methodology, interpretation and content. Edited and copy edited the review.
Ruth Foxlee: designed the search strategy and edited the search methods section.

 

Declarations of interest

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

Prof Scuffham is the director of a unit contracted to the Australian Department of Health and Ageing to undertake external evaluations of industry submissions to the PBAC.
Joan Webster, Monica Stankiewicz, Karen Sherriff, Wendy Chaboyer - none declared.

 

Sources of support

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Internal sources

  • Royal Brisbane and Women's Hospital, Australia.
    Time to conduct review
  • Griffith University, Australia.
    Time to conduct review

 

External sources

  • NIHR/Department of Health (England), (Cochrane Wounds Group), UK.

 

Differences between protocol and review

  1. Top of page
  2. Background
  3. Objectives
  4. Methods
  5. Results
  6. Discussion
  7. Authors' conclusions
  8. Acknowledgements
  9. Data and analyses
  10. Appendices
  11. What's new
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

We added one intervention: comparisons between different negative pressure devices.

The list of abstracted data was expanded to include:

  • study dates;
  • number of participants per group;
  • information about ethics approval, consent and conflict of interest.

In trials of skin grafts, graft failure is an important outcome. We failed to include this as either a primary or secondary outcome but believe, for future updates that skin graft failure should be included. We also failed to include length of hospital stay, which is important for any economic analysis. Consequently, graft failure and length of hospital stay have been included as additional outcomes post hoc.

* Indicates the major publication for the study

References

References to studies included in this review

  1. Top of page
  2. Abstract摘要
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. What's new
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to studies awaiting assessment
  22. References to ongoing studies
  23. Additional references
Chio 2010 {published and unpublished data}
  • Chio EG, Agrawal A. A randomized, prospective, controlled study of forearm donor site healing when using a vacuum dressing. Otolaryngology - Head and Neck Surgery 2010;142(2):174-8.
Dorafshar 2011 {published data only (unpublished sought but not used)}
  • Dorafshar AH, Franczyk M, Gottlieb LJ, Wroblewski KE, Lohman RF. A prospective randomized trial comparing subatmospheric wound therapy with a sealed gauze dressing and the standard vacuum-assisted closure device. Annals of Plastic Surgery 2011;Jun 27:[Epub ahead of print].
Howell 2011 {published and unpublished data}
  • Howell RD, Hadley S, Strauss E, Pelham FR. Blister formation with negative pressure dressings after total knee arthroplasty. Current Orthopaedic Practice 2011;22:176-9.
Llanos 2006 {published and unpublished data}
  • Llanos S, Danilla S, Barraza C, Armijo E, Pineros JL, Quintas M, et al. Effectiveness of negative pressure closure in the integration of split thickness skin grafts. A randomized, double-masked, controlled trial. Annals of Surgery 2006;244(5):700–5.
Pachowsky 2011 {published data only}
  • Pachowsky M, Gusinde J, Klein A, Lehrl S, Schulz-Drost S, Schlechtweg P, et al. Negative pressure wound therapy to prevent seromas and treat surgical incisions after total hip arthroplasty. International Orthopaedics 2011;Jul 15 [Epub ahead of print]:DOI: 10.1007/s00264-011-1321-8.

References to studies excluded from this review

  1. Top of page
  2. Abstract摘要
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. What's new
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to studies awaiting assessment
  22. References to ongoing studies
  23. Additional references
Hu 2009 {published data only}
  • Hu KX, Zhang HW, Zhou F, Yao G, Shi JP, Wang LF, et al. A comparative study of the clinical effects between two kinds of negative-pressure wound therapy. Zhonghua Shao Shang Za Zhi 2009;24:253-7.
Johannesson 2008 {published data only}
  • Johannesson A, Larsson GU, Oberg T, Atroshi I. Comparison of vacuum-formed removable rigid dressing with conventional rigid dressing after transtibial amputation: similar outcome in a randomized controlled trial involving 27 patients. Acta Orthopaedica 2008;97:361-9.
Kim 2007 {published data only}
Moues 2004 {published data only}
  • Moues CM// Van Den Bemd GJ// Heule F// Hovius SER. A prospective randomized trial comparing vacuum therapy to conventional moist gauze therapy. 2nd World Union of Wound Healing Societies Meeting; 2004 ,8-13 July; Paris. 2004:6, Abstract no. A001.
  • Moues CM// Van Den Bemd GJ// Meerding WJ// Hovius SER. Cost analysis comparing vacuum-assisted closure wound therapy to conventional moist gauze therapy. 2nd World Union of Wound Healing Societies Meeting; 2004 ,8-13 July; Paris. 2004:87, Abstract no. A008.
  • Mouës CM, Vos MC, van den Bemd GJ, Stijnen T, Hovius SE. Bacterial load in relation to vacuum-assisted closure wound therapy. 13th Conference of the European Wound Management Association; 2003, 22-24 May; Pisa, Italy. 2003:69.
  • Mouës CM, Vos MC, van den Bemd GJ, Stijnen T, Hovius SE. Bacterial load in relation to vacuum-assisted closure wound therapy: a prospective randomized trial. Wound Repair and Regeneration 2004;12:11-7.
Moues 2007 {published data only}
  • Mouës CM, van den Bemd GJ, Heule F, Hovius SE. Comparing conventional gauze therapy to vacuum-assisted closure wound therapy: a prospective randomised trial. Journal of Plastic and Reconstructive Aesthetic Surgery 2007;60:672-81.

References to studies awaiting assessment

  1. Top of page
  2. Abstract摘要
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. What's new
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to studies awaiting assessment
  22. References to ongoing studies
  23. Additional references
Braakenburg 2006 {published data only}
  • Braakenburg A, Obdeijn MC, Feitz R, van Rooij IA, van Griethuysen AJ, Klinkenbijl JH. The clinical efficacy and cost effectiveness of the vacuum-assisted closure technique in the management of acute and chronic wounds: a randomized controlled trial. Plastic and Reconstructive Surgery 2006;118:390-7.
Moisidis 2004 {published data only}
  • Moisidis E, Heath T, Boorer C, Ho K, Deva AK. A prospective, blinded, randomized, controlled clinical trial of topical negative pressure use in skin grafting. Plastic and Reconstructive Surgery 2004;114:917-22.

References to ongoing studies

  1. Top of page
  2. Abstract摘要
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. What's new
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to studies awaiting assessment
  22. References to ongoing studies
  23. Additional references
Chan 2011 {unpublished data only}
  • A prospective randomised control trial of negative pressure suction dressing and early mobilisation in the management of lower leg skin grafts. Register: ANZCTR Registration ID: ACTRN12609000995279.
Graves 2011 {unpublished data only}
  • Incisional wound vac in obese patients. Register: ClinicalTrials.gov Registration ID: NCT00789659.

Additional references

  1. Top of page
  2. Abstract摘要
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. What's new
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to studies awaiting assessment
  22. References to ongoing studies
  23. Additional references
Abuzakuk 2006
  • Abuzakuk TM, Coward P, Shenava Y, Kumar VS, Skinner JA. The management of wounds following primary lower limb arthroplasty: a prospective, randomised study comparing hydrofibre and central pad dressings. International Wound Journal 2006;3:133-7.
Allen 2011
  • Allen G, Kirk J, Jones J, Rauen B, Fritzsche S. Navigating new technologies in negative pressure wound therapy. Plastic Surgical Nursing 2011;31:65-72.
Altman 2001
Andersson 2010
  • Andersson AE, Bergh I, Karlsson J, Nilsson K. Patients' experiences of acquiring a deep surgical site infection: an interview study. American Journal of Infection Control 2010;38(9):711-7.
Apostoli 2008
  • Apostoli A, Caula C. Pain and basic functional activities in a group of patients with cutaneous wounds under V.A.C therapy in hospital setting. Professioni Infermieristiche 2008;61(3):158-64.
Australian Institute of Health and Welfare 2010
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Banwell 2003
  • Banwell PE, Teot L. Topical negative pressure (TNP): the evolution of a novel wound therapy. Journal of Wound Care 2003;12:22-8.
Baronski 2008
  • Baronski S, Ayello E. Wound Care Essentials. Practice and Principles. Ambler, PA: Lippincott, Williams & Wilkins, 2008.
Blume 2010
Citak 2010
  • Citak M, Backhaus M, Meindl R, Muhr G, Fehmer T. Rare complication after VAC-therapy in the treatment of deep sore ulcers in a paraplegic patient. Archives of Orthopaedic Trauma Surgery 2010;130:1511-4.
Coulthard 2010
CRD 2010
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Culliford 2007
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DeCarbo 2010
Dragu 2010
  • Dragu A, Schnurer S, Unglaub F, Wolf MB, Beier JP, Kneser U, et al. Wide topical negative pressure wound dressing treatment for patients undergoing abdominal dermolipectomy following massive weight loss. Obesity Surgery 2010;Nov 26:Epub ahead of print. [DOI: 10.1007/s11695-010-0328-3]
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Eneroth 2008
Expert Working Group 2008
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Fleischmann 1997
Gregor 2008
Gurtner 2008
Harvey 2005
  • Harvey C. Wound healing. Orthopaedic Nursing 2005;24:143-57.
Heuser 2005
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Higgins 2011
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Kairinos 2009
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Kanakaris 2007
  • Kanakaris NK, Thanasas C, Keramaris N, Kontakis G, Granick MS, Giannoudis PV. The efficacy of negative pressure wound therapy in the management of lower extremity trauma: review of clinical evidence. Injury 2007;38(Suppl 5):S9-18.
Keskin 2008
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Kloth 2002
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Koval 2007
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Krug 2011
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Lefebvre 2011
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Mody 2008
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Molnar 2005
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Morykwas 1997
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Morykwas 2001
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NICE 2009
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Olbrecht 2006
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Ortega 2010
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Perez 2010
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Petzina 2010
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Ravenscroft 2006
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WHO 2009