A nurse is assessing a client who has had staples removed from an abdominal wound postoperatively

Monitoring Editor: Jo C Dumville,

University of Manchester, Division of Nursing, Midwifery & Social Work, School of Health Sciences, Faculty of Biology, Medicine & Health, ManchesterUK, M13 9PL

Gloucestershire NHS Foundation Trust, Colorectal Surgery, Cheltenham General, Sandford Road, CheltenhamUK, GL53 7AN

The Wound Centre, PO Box 3207, Blakehurst, SydneyNew South WalesAustralia, 2221

Royal Adelaide Hospital, Level 4, Margaret Graham Building, North Terrace, AdelaideAustralia, SA5000

University of Adelaide, Level 3, Eleanor Harrald Building, North Terrace, AdelaideAustralia, SA 5000

University of Bristol, University of Bristol, School of Social and Community Medicine, Canynge Hall, 39 Whatley Road, BristolUK, BS28 2PS

University of Bristol, School of Clinical Sciences, Level 7, Bristol Royal Infirmary, Marlborough Street, BristolUK, BS2 8HW

University of Bristol, Bristol Centre for Surgical Research, School of Social & Community Medicine, Canynge Hall, 39 Whatley Road, BristolUK, BS8 2PS

Jo C Dumville, Email: .

Author information Copyright and License information Disclaimer

University of Manchester, Division of Nursing, Midwifery & Social Work, School of Health Sciences, Faculty of Biology, Medicine & Health, ManchesterUK, M13 9PL

Gloucestershire NHS Foundation Trust, Colorectal Surgery, Cheltenham General, Sandford Road, CheltenhamUK, GL53 7AN

The Wound Centre, PO Box 3207, Blakehurst, SydneyNew South WalesAustralia, 2221

Royal Adelaide Hospital, Level 4, Margaret Graham Building, North Terrace, AdelaideAustralia, SA5000

University of Adelaide, Level 3, Eleanor Harrald Building, North Terrace, AdelaideAustralia, SA 5000

University of Bristol, University of Bristol, School of Social and Community Medicine, Canynge Hall, 39 Whatley Road, BristolUK, BS28 2PS

University of Bristol, School of Clinical Sciences, Level 7, Bristol Royal Infirmary, Marlborough Street, BristolUK, BS2 8HW

University of Bristol, Bristol Centre for Surgical Research, School of Social & Community Medicine, Canynge Hall, 39 Whatley Road, BristolUK, BS8 2PS

Jo C Dumville, Email: .

Copyright © 2016 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

Surgical wounds (incisions) heal by primary intention when the wound edges are brought together and secured, often with sutures, staples, or clips. Wound dressings applied after wound closure may provide physical support, protection and absorb exudate. There are many different types of wound dressings available and wounds can also be left uncovered (exposed). Surgical site infection (SSI) is a common complication of wounds and this may be associated with using (or not using) dressings, or different types of dressing.

To assess the effects of wound dressings compared with no wound dressings, and the effects of alternative wound dressings, in preventing SSIs in surgical wounds healing by primary intention.

We searched the following databases: the Cochrane Wounds Specialised Register (searched 19 September 2016); the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2016, Issue 8); Ovid MEDLINE (including In‐Process & Other Non‐Indexed Citations, MEDLINE Daily and Epub Ahead of Print; 1946 to 19 September 2016); Ovid Embase (1974 to 19 September 2016); EBSCO CINAHL Plus (1937 to 19 September 2016).

There were no restrictions based on language, date of publication or study setting.

Randomised controlled trials (RCTs) comparing wound dressings with wound exposure (no dressing) or alternative wound dressings for the postoperative management of surgical wounds healing by primary intention.

Two review authors performed study selection, 'Risk of bias' assessment and data extraction independently.

We included 29 trials (5718 participants). All studies except one were at an unclear or high risk of bias. Studies were small, reported low numbers of SSI events and were often not clearly reported. There were 16 trials that included people with wounds resulting from surgical procedures with a 'clean' classification, five trials that included people undergoing what was considered 'clean/contaminated' surgery, with the remaining studies including people undergoing a variety of surgical procedures with different contamination classifications. Four trials compared wound dressings with no wound dressing (wound exposure); the remaining 25 studies compared alternative dressing types, with the majority comparing a basic wound contact dressing with film dressings, silver dressings or hydrocolloid dressings. The review contains 11 comparisons in total.

Primary outcome: SSI

It is uncertain whether wound exposure or any dressing reduces or increases the risk of SSI compared with alternative options investigated: we assessed the certainty of evidence as very low for most comparisons (and low for others), with downgrading (according to GRADE criteria) largely due to risk of bias and imprecision. We summarise the results of comparisons with meta‐analysed data below:

‐ film dressings compared with basic wound contact dressings following clean surgery (RR 1.34, 95% CI 0.70 to 2.55), very low certainty evidence downgraded once for risk of bias and twice for imprecision.

‐ hydrocolloid dressings compared with basic wound contact dressings following clean surgery (RR 0.91, 95% CI 0.30 to 2.78), very low certainty evidence downgraded once for risk of bias and twice for imprecision.

‐ hydrocolloid dressings compared with basic wound contact dressings following potentially contaminated surgery (RR 0.57, 95% CI 0.22 to 1.51), very low certainty evidence downgraded twice for risk of bias and twice for imprecision.

‐ silver‐containing dressings compared with basic wound contact dressings following clean surgery (RR 1.11, 95% CI 0.47 to 2.62), very low certainty evidence downgraded once for risk of bias and twice for imprecision.

‐ silver‐containing dressings compared with basic wound contact dressings following potentially contaminated surgery (RR 0.83, 95% CI 0.51 to 1.37), very low certainty evidence downgraded twice for risk of bias and twice for imprecision.

Secondary outcomes

There was limited and low or very low certainty evidence on secondary outcomes such as scarring, acceptability of dressing and ease of removal, and uncertainty whether wound dressings influenced these outcomes.

It is uncertain whether covering surgical wounds healing by primary intention with wound dressings reduces the risk of SSI, or whether any particular wound dressing is more effective than others in reducing the risk of SSI, improving scarring, reducing pain, improving acceptability to patients, or is easier to remove. Most studies in this review were small and at a high or unclear risk of bias. Based on the current evidence, decision makers may wish to base decisions about how to dress a wound following surgery on dressing costs as well as patient preference.

Dressings for the prevention of surgical site infection

Review question

This review aimed to assess whether use of different wound dressings (or leaving a wound exposed without a dressing) has an impact on the number of people who get wound infections following surgery where the wound is closed with stitches, staples, clips or glue. We also investigated whether different dressings resulted in less pain, less scarring or were more acceptable to patients and health professionals.

Background

Millions of surgical procedures are conducted globally each year. The majority of procedures result in wounds in which the edges are brought together to heal using stitches, staples, clips or glue; this is called 'healing by primary intention'. Afterwards, wounds are often covered with a dressing that acts as a barrier between it and the outside environment. One possible advantage of a dressing may be to protect the wound from infection (surgical site infection). Many different dressing types are available for use on surgical wounds. However, it is not clear whether one type of dressing is better than any other in preventing surgical site infection, or, indeed, whether it is better not to use a dressing at all.

Study characteristics

We conducted a review of all available, relevant evidence about the impact of dressings on the prevention of surgical site infections in surgical wounds healing by primary intention. This review examined data from 29 randomised controlled trials (which provide the most reliable evidence). These investigated the use of dressings in surgery that had a low risk of surgical site infection (clean surgery) and surgery with a higher risk (potentially contaminated surgery).

Key results

We found no clear evidence to suggest that one dressing type was better than any other at reducing the risk of surgical site infection, nor that covering wounds with any dressing at all reduced the risk of surgical site infection. Additionally, there was no clear evidence that any dressing type improves scarring, pain control, patient acceptability or ease of removal. Currently decision makers may opt to make decisions about whether and how to dress a wound based on patient and clinician preferences and dressing costs.

Certainty of the evidence

It is important to note that many trials in this review were small and the evidence was of low or very low certainty meaning that current information is uncertain.

Assessed as up to date September 2016.

Millions of surgical procedures are conducted around the world each year. The majority of procedures result in surgical wounds that will heal by primary intention. This is where wound edges are re‐approximated using sutures, staples, clips or glue, either alone, or in combination. Following wound closure, surgical wounds commonly leak fluid or blood within the first 24 hours and they are frequently covered with different types of dressing ‐ including glue‐as‐a‐dressing (tissue glue applied over a wound that has already been closed) ‐ to manage the exudate, provide wound protection and prevent possible external contamination that might lead to surgical site infection (SSI) and delayed healing. A study in the USA found that in over 750,000 episodes of surgical hospitalisation, 1% resulted in an SSI (de Lissovoy 2009), and similar estimates have been found in France (Astagneau 2009). However, such values are known to underestimate the levels of SSI by not considering those that develop outside hospitals (Bruce 2001; Gibbons 2011). In the UK it has been estimated that 4% to 5% of patients undergoing a surgical procedure contract an SSI (Health Protection Agency 2002; Smyth 2008), but this percentage varies greatly depending on the circumstances. Whilst various patient factors can predict the likelihood of SSI, the type of surgical procedure performed exerts a major influence on risk. Surgical procedures involving 'clean' body cavities have much lower numbers of infection, around 3% to 5%, compared with procedures involving body cavities with infected, necrotic or dirty tissue, for example, colorectal surgery, which have surgical infection figures of around 10% to 30% (McLaws 2000). A widely used definition that describes the contamination classification of surgical procedures is given below:

Clean: non‐infective operative wounds in which no inflammation is encountered, and neither the respiratory, alimentary, genitourinary tract nor the oro‐pharyngeal cavity is entered. In addition these cases are elective, primarily closed, and drained with closed drainage system when required.

Clean/contaminated: operative wounds in which the respiratory, alimentary, genital or urinary tract is entered under controlled conditions and without unusual contamination. Specifically, operations involving the biliary tract, appendix, vagina and oropharynx are included in this category, provided no evidence of infection or a major break in sterile technique is encountered.

Contaminated: fresh, accidental wounds, operations with major breaks in sterile technique or gross spillage from the gastrointestinal tract, and incisions in which acute, non‐purulent inflammation is encountered.

Dirty: old traumatic wounds with retained devitalised tissue and those that involve existing clinical infection or perforated viscera. This definition suggests that organisms causing postoperative infection were present in the operative field before the operation.

SSIs not only cause considerable patient morbidity, but also increase the consumption of healthcare resources. In the UK, the mean additional cost of treating an infected surgical wound (compared with a non‐infected wound) was estimated at GBP 1618 (Plowman 2001), with much of this extra cost attributable to an increased length of hospital stay (mean increase of 6.5 days) (Plowman 2001). In the USA, de Lissovoy 2009 estimated that the extended length of stay and increased treatment costs associated with SSIs over a one‐year period led to approximately 1 million additional inpatient‐days, costing an additional USD 1.6 billion.

Whilst SSIs can be difficult to define (one review identified 41 different definitions and 13 grading scales of SSI (Bruce 2001)), the Centers for Disease Control and Prevention (CDC) have published the following guidelines defining superficial and deep incisional SSIs (Horan 2008). A superficial SSI is defined as: an infection occurring within 30 days after the operation, that only involves the skin and subcutaneous tissue of the incision, and is associated with at least one of the following:

• purulent drainage, with or without laboratory confirmation, from the surgical site;

• organisms isolated from an aseptically‐obtained culture of fluid or tissue from the surgical site;

• at least one of the following signs or symptoms of infection: pain or tenderness, localised swelling, redness or heat, and the superficial incision is deliberately opened by the surgeon and is culture‐positive or not cultured (a culture‐negative finding does not meet this criterion);

• diagnosis of SSI by the surgeon or attending physician.

A deep incisional SSI is defined as: infection that occurs within 30 days after the operative procedure if no implant is left in place, or within one year if an implant is left in place, and the infection appears to be related to the operative procedure and involves deep soft tissues (e.g. fascial and muscle layers) of the incision associated with one of the following:

• purulent drainage from the deep incision, but not from the organ/space component of the surgical site;

• a deep incision spontaneously dehisces (opens up) or is deliberately opened by the surgeon and is culture‐positive or not cultured when the patient has at least one of the following symptoms: fever or localised pain or tenderness;

• an abscess, or other evidence of infection involving the deep incision is found on direct examination, during re‐operation, or by histopathologic or radiologic examination;

• diagnosis of a deep incisional SSI by a surgeon or attending physician.

Dressings are widely used in the care of wounds. Several attributes of an ideal wound dressing have been described (BNF 2016; Goldman 1992; NICE 2008); these include:

• the ability of the dressing to absorb and contain exudate without leakage or strike‐through;

• lack of particulate contaminants left in the wound by the dressing;

• thermal insulation;

• impermeability to water and bacteria;

• suitability of the dressing for use with different skin closures (sutures, staples);

• avoidance of wound trauma on dressing removal;

• frequency with which the dressing needs to be changed;·

• provision of pain relief;

• cosmesis and comfort;

• effect on formation of scar tissue;

• transparency to aid visualisation of the wound.

Dressing products have evolved considerably in the last few decades, and now fall into broad, widely‐recognised categories, namely:

• basic wound contact dressings such as gauze or cotton absorbents;

• 'advanced' dressings such as hydrogels, hydrocolloids and films;

• antimicrobial and other specialist dressings; and, more recently

• topical skin adhesives, which can be used to cover an already closed wound ‐ 'glue‐as‐a‐dressing'.

Within these groups there are many hundreds of dressing types available. For ease of comparison in this review, dressings have been classified into groups according to the British National Formulary (BNF) (BNF 2016). However, it is important to note that the distributors of dressings may vary from country to country, and that dressing names may also vary. Below we summarise key dressing groups as well as noting wound exposure where no dressing is used to cover a wound.

Wound exposure

In some cases wounds may be left uncovered following surgery. They may have no dressing at all applied or a simple pad placed on the closed wound to absorb leakage which is removed shortly after.

Basic wound contact dressings

Absorbent dressings and surgical absorbents

Absorbent dressings are applied directly to the wound. Surgical absorbents may be used as secondary absorbent layers in the management of heavily‐exuding wounds. Examples include Primapore® (Smith & Nephew), Mepore® (Mölnlycke), and absorbent cotton gauze, BP 1988.

Low‐adherence dressings and wound contact materials

Low adherence dressings and wound contact materials are usually cotton pads that are placed directly in contact with the wound. They are either non‐medicated (e.g. paraffin gauze dressing), or medicated (e.g. containing povidone iodine or chlorhexidine). Examples include paraffin gauze dressing, BP 1993, Xeroform Dressing® ‐ a non‐adherent petrolatum blend with 3% bismuth tribromophenate on fine mesh gauze.

Advanced dressings

Vapour‐permeable films

Vapour‐permeable films are permeable to water vapour and oxygen, but not to water or micro‐organisms. They are normally transparent. Examples include OpSite® (Smith & Nephew) and Tegaderm® (3M).

Hydrocolloid dressings

Hydrocolloid dressings are occlusive dressings composed of a hydrocolloid matrix attached to a base (possibly film or foam). Fluid absorbed from the wound causes the hydrocolloid to liquefy. Examples include Comfeel® (Coloplast) and DuoDerm® (ConvaTec, UK).

Fibrous hydrocolloid dressing (hydrofibre, spun hydrocolloid dressings)

Fibrous hydrocolloid dressings are composed of sodium carboxymethylcellulose which forms a gel when it comes into contact with fluid. Examples include Aquacel® (ConvaTec, UK).

Polyurethane matrix hydrocolloid dressing

Polyurethane matrix hydrocolloid dressings consist of two layers ‐ a polyurethane gel matrix and a waterproof polyurethane top‐film designed to act as a bacterial barrier. There is only one dressing of this type listed in the BNF: Cutinova® Hydro (Smith & Nephew).

Antimicrobial dressings

Polyhexametylene biguanide (PHMB) dressing

PHMB dressings are impregnated with the antimicrobial agent polyhexanide.

Topical skin adhesives (glue‐as‐dressing)

Skin tissue adhesives are currently described in the BNF as being indicated for closure of minor skin wounds and for additional suture support. However, they can be used on an already closed wound as a dressing without an additional covering. They act as a barrier, are sterile before application and contain enbucrilate or octyl 2‐cyanoacrylate.

Current practice for some surgical wounds healing by primary intention involves placement of a dressing over the closed wound before the patient leaves the clean environment of the operating theatre. This practice assumes that the risk of SSIs may be reduced by providing a barrier to environmental contamination. Furthermore, dressings may have additional roles in managing wound exudate, protecting wounds and their staples or sutures, and meeting patients' expectations by 'hiding' the wound, or, alternatively, when transparent dressings are used, facilitating health professionals' observation of the wound. Conversely, in other practices (e.g. paediatric surgery) it is usual not to use a dressing. This practice assumes that the risk of SSIs may be reduced by allowing the wound to dry. When wounds are covered by 'glue‐as‐a‐dressing' it is also assumed that this acts as a barrier that may reduce external infection.

Surgical wounds healing by primary intention are commonplace within all elective and emergency surgical practice. It is important to assess whether wound dressings have a potential role in reducing the risk of SSI. Such information could inform allocation of resources to appropriate treatments. Currently these decisions are made with limited review data. In the UK, a government‐funded guideline reviewed the data from five trials that are relevant to this review, and concluded that existing studies did not show convincing differences in dressing effectiveness in terms of reducing SSI (NICE 2008). Whilst the review methods were robust, the search date was September 2007, and so studies published after this date were not assessed. Recent World Health Organisation guidelines have been published which assess one group of dressings, advanced dressings, compared with standard dressings (Allegranzi 2016).

To assess the effects of wound dressings compared with no wound dressings, and the effects of alternative wound dressings, in preventing SSIs in surgical wounds healing by primary intention.

Types of studies

Randomised controlled trials (RCTs) that compared the immediate postoperative application of wound dressings with no wound dressings, or compared alternative dressings, for surgical wounds expected to heal by primary intention.

Types of participants

Studies involving adults or children (aged two years and over) who had undergone surgical procedures where healing of the surgical wound was planned by primary intention. Wounds of any contamination level (clean, clean/contaminated, contaminated and dirty) were eligible for inclusion. We excluded procedures involving graft sites, and wounds of the mouth and eye. Participants were required to have dressings applied in the operating theatre, immediately after closure of the skin. We excluded studies where participants had infected wounds at the start of the study.

Types of interventions

The primary intervention was wound exposure or application of wound dressings that could be:

• basic wound contact dressings: classed as surgical and non‐surgical absorbent dressings, low‐adherence dressings, impregnated/non‐impregnated gauze, and adhesive tape;

• advanced wound dressings such as hydrogels, hydrocolloids and films;

• antimicrobial and other specialist dressings;

• tissue adhesive used as a dressing (glue‐as‐dressing) on an already closed wound.

We included comparisons of a dressing versus no dressing (exposed wound), and versus alternative dressings. We did not consider trials that compared different application durations of the same dressing (timing trials), as these will form a separate review. Nor did we include trials where the application of topical gels or ointments to wounds (in the absence of a dressing comparator) was evaluated, as we viewed these as different interventions. We did not include trials where the application of tissue adhesive was for the purpose of closing the wound only. The only difference between trial groups for included studies was the method of wound coverage used.

Types of outcome measures

Primary outcomes

Occurence of postoperative SSI as defined by the CDC criteria (Horan 2008), or the authors' definition of SSI. We did not differentiate between superficial and deep‐incisional infection.

Secondary outcomes

• Scarring: as reported by the author.

• Pain: reported using a validated scale or as reported by the author.

• Acceptability (participant and clinician): as reported by the author.

• Ease of removal (participant and clinician): as reported by the author.

• Cost: any measure of cost of treatment, or other aspects of resource use i.e. other equipment.

Electronic searches

In September 2016 for our second update of this review we searched the following electronic databases:

• the Cochrane Wounds Specialised Register (searched 19 September 2016);

• the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2016, Issue 8);

• Ovid MEDLINE (including In‐Process & Other Non‐Indexed Citations, MEDLINE Daily and Epub Ahead of Print; 1946 to 19 September 2016);

• Ovid Embase (1974 to 19 September 2016);

• EBSCO CINAHL Plus (1937 to 19 September 2016).

The search string for CENTRAL can be found in Appendix 1. The search methods used for the original version of this review can be found in Appendix 2.The search strategies for Ovid MEDLINE, Ovid Embase and EBSCO CINAHL can be found in: Appendix 3; Appendix 4; and Appendix 5. The Ovid MEDLINE search was combined 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 search with the Ovid EMBASE filter developed by the UK Cochrane Centre (Lefebvre 2011). We combined the CINAHL searches with the trial filters developed by the Scottish Intercollegiate Guidelines Network (SIGN 2015). There were no restrictions with respect to language, date of publication or study setting.

Searching other resources

We searched the bibliographies of all retrieved and relevant publications identified by these strategies for further studies. While handsearches were not performed for this review, they are conducted by Cochrane Wounds in order to inform the CENTRAL database, which we searched. We did not contact manufacturers of dressings regarding studies for inclusion.

We also searched the following clinical trials registries.

• ClinicalTrials.gov (www.clinicaltrials.gov).

• the World Health Organization (WHO) International Clinical Trials Registry Platform (apps.who.int/trialsearch/Default.aspx).

• EU Clinical Trials Register (www.clinicaltrialsregister.eu).

Selection of studies

Two review authors independently assessed the studies' titles and abstracts against the review's inclusion criteria. After this initial assessment, we obtained all studies that might meet these criteria in full. Full papers were checked for eligibility by two review authors, with disagreements resolved by discussion and, where required, the input of a third review author. We extracted details of the eligible studies, and summarised them on a data extraction sheet. Two review authors extracted data independently. If data were missing from reports, we made attempts to contact the study authors to obtain the missing information. Studies that were published in duplicate we only included once, but extracted the maximum amount of data from the papers.

Data extraction and management

All data were extracted independently by two review authors. The following data were extracted:

• country in which the trial was conducted;

• type of surgery;

• classification of surgical contamination (see Table 10 for classification guide);

  Classification of surgical contamination of included studies

  Classification	Description	Study classification
  Clean only	Non‐infective operative wounds in which no inflammation is encountered, and neither the respiratory, alimentary, genitourinary tract nor the oro‐pharyngeal cavity is entered. In addition these cases are elective, primarily closed, and drained with closed drainage system when required.	Burke 2012; Cosker 2005; De Win 1998; Dickinson Jennings 2015; Lawrentschuk 2002; Law 1987; Langlois 2015; Martin‐Trapero 2013; Michie 1994; Moshakis 1984; Politano 2011; Ravnskog 2011; Vogt 2007; Wikblad 1995; Wynne 2004
  Clean/contaminated only	Operative wounds in which the respiratory, alimentary, genital or urinary tract is entered under controlled conditions and without unusual contamination. Specifically, operations involving the biliary tract, appendix, vagina and oropharynx are included in this category, provided no evidence of infection or a major break in sterile technique is encountered.	Persson 1995; Ruiz‐Tovar 2015 Not reported for Biffi 2012; Kriegar 2011; Siah 2011 but we put them in this class on the basis of details reported.
  Contaminated only	Fresh, accidental wounds, operations with major breaks in sterile technique or gross spillage from the gastrointestinal tract, and incisions in which acute, non‐purulent inflammation is encountered.
  Dirty only	Old traumatic wounds with retained devitalised tissue and those that involve existing clinical infection or perforated viscera. This definition suggests that organisms causing postoperative infection were present in the operative field before the operation.
  Mixed		Bennett 2013 (clean and possibly clean/contaminated and contaminated) Gardezi 1983;(clean, clean/contaminated and possibly contaminated) Hewlett 1996; (predominately clean, some clean/contaminated and possibly contaminated) Holm 1998; (clean, clean/contaminated and contaminated) Ozaki 2015 (25/500 participants were clean‐contaminated and the remaining 475 were clean surgery) Phan 1993; (clean, clean/contaminated) Shinohara 2008; (clean, clean/contaminated and possibly contaminated)
  No classification		Rohde 1979; Prather 2011

• eligibility criteria;

• details of the dressing/treatment regimen received by each group, including the duration that the dressing was in situ;

• primary and secondary outcome(s) (with definitions);

• outcome data for primary and secondary outcomes (by group);

• duration of follow‐up;

• number of withdrawals (by group).

Assessment of risk of bias in included studies

Two review authors independently assessed each included study for risk of bias. Assessment was undertaken using the Cochrane `Risk of bias' tool (Higgins 2011). This tool considers six domains: sequence generation, allocation concealment, blinding, incomplete outcome data, freedom from selective reporting, and other issues (i.e. serious baseline imbalance). A `Risk of bias' table was completed for each eligible study; these data were combined into a `Risk of bias' summary figure where we have tabulated judgements for each domain by study.

Measures of treatment effect

We presented results with 95% confidence intervals (CI). We reported estimates for dichotomous outcomes (e.g. infected: yes/no) as risk ratios (RR) (Deeks 2002). We reported continuous data (e.g. pain) as mean differences (MD), and we calculated overall effect sizes (with 95% CI). 

Unit of analysis issues

When we located three‐armed trials where only two of the arms were relevant to the review, we did not extract data for the non‐relevant arm. When three‐armed studies had two arms randomised to receive different brands of the same dressing, we combined these into one group and treated the trial as a two‐armed trial. We did not combine arms in three‐armed trials when all the arms received different, relevant interventions, in those cases we included all relevant comparisons.

Dealing with missing data

We did not consider the issue of missing data in the protocol for this review. The problem of missing data is common in trials, especially those of poor quality. Excluding participants from the analysis after randomisation, or ignoring participants lost to follow‐up can, in effect, undo the process of randomisation, and thus, potentially, introduce bias into the trial. For our primary outcome, SSI, we assumed that where randomised participants were not included in an analysis, they did not have an SSI (that is they were considered in the denominator but not the numerator). Given the relatively small number of SSI events anticipated, this seemed the most appropriate assumption. When a trial did not specify participant group numbers prior to drop out, we presented only complete case data. We present data for all secondary outcomes as complete case analysis.

Assessment of heterogeneity

Our assessment of heterogeneity comprised an initial assessment of clinical and methodological heterogeneity and the appropriateness of combining study results: that is the degree to which the included studies varied in terms of participant, intervention, outcome and characteristics such as length of follow‐up. We supplemented this assessment of clinical and methodological heterogeneity with information regarding statistical heterogeneity of the results ‐ assessed using the Chi² test (we considered that a significance level of P < 0.10 indicated statistically significant heterogeneity) in conjunction with the I² measure (Higgins 2003). I² examines the percentage of total variation across RCTs that is due to heterogeneity rather than chance (Higgins 2003). In general I² values of 25%, or less, may mean a low level of heterogeneity (Higgins 2003), and values of 75%, or more, indicate very high heterogeneity (Deeks 2011). We also examined the variability of the point estimates and the overlap of the confidence intervals, when I² values were less than 50%. Where there was evidence of high heterogeneity we explored this further: see Data synthesis.

Assessment of reporting biases

Reporting biases arise when the dissemination of research findings is influenced by the nature and direction of results. Publication bias, an across‐study reporting bias, is one of a number of possible causes of 'small study effects', that is, a tendency for estimates of the intervention effect to appear to be more beneficial in smaller RCTs. Funnel plots allow a visual assessment of whether small study effects may be present in a meta‐analysis. A funnel plot is a simple scatter plot of the effect estimates from individual RCTs against some measure of trial size or precision (Sterne 2011). If we had meta‐analyses that included 10 or more RCTs, we would have presented funnel plots using Cochrane Review Manager 5 software (RevMan 2014). However, we did not have sufficient studies for this.

Data synthesis

We combined details of included studies in a narrative review according to dressing type and stratified by surgical contamination level. We explored both clinical and statistical heterogeneity. Where appropriate, we pooled data using meta‐analysis (conducted using RevMan 5), that is, where studies were considered similar in terms of intervention type, duration, and outcomes. We assessed statistical heterogeneity using the Chi² test (we considered that a significance level of P value less than 0.1 indicated heterogeneity), and the I² test (Higgins 2003). In the absence of clinical heterogeneity, and in the presence of statistical heterogeneity (I² over 50%), we used a random‐effects model. Where there was no clinical or statistical heterogeneity, we applied a fixed‐effect model.

GRADE assessment and 'Summary of findings' tables

We presented the main results of the review in 'Summary of findings’ tables for the following comparisons:

• basic wound contact dressings compared with exposed wounds;

• specific advanced dressings compared with exposed wounds;

• basic wound dressings compared with specific advanced dressings e.g. film, hydrocolloid;

• basic wound contact dressings compared with antimicrobial dressings.

These tables present key information concerning the certainty of the evidence, the magnitude of the effects of the interventions examined, and the sum of available data for the main outcomes (Schünemann 2011a). The 'Summary of findings’ tables also include an overall grading of the evidence related to each of the main outcomes using the GRADE approach. This defines the certainty of a body of evidence as the extent to which one can be confident that an estimate of effect or association is close to the true quantity of specific interest. The certainty of a body of evidence involves consideration of within‐trial risk of bias (methodological quality), directness of evidence, heterogeneity, precision of effect estimates and risk of publication bias (Schünemann 2011b). We present the following outcomes in the 'Summary of findings’ tables:

• SSI;

• scarring;

• acceptability of dressing to patient;

• ease of dressing removal.

For relevant outcomes reported for comparisons not listed above we have presented GRADE assessments without a 'Summary of findings' table.

In terms of the GRADE assessment, when making decisions for the risk of bias domain we downgraded only when we had classed studies as being at high risk of bias for one or more domains and/or they were classed as being at unclear risk of bias for both domains that contribute to selection bias. In assessing the precision of effect estimates for SSI we followed GRADE guidance (GRADE 2013), and calculated an optimal information size (OIS) using conventional sample size calculation methods. We used the OIS, along with the size of 95% CIs ‐ in terms of whether they spanned estimates of benefit and harm ‐ to assess for downgrading. We calculated the OIS based on GRADE guidance of using a relative risk reduction of between 20% and 30%. The OIS is summarised below but should not be treated as optimal sample sizes for any future research. Within a GRADE assessment the OIS is used to assess the stability of CIs rather than to assess the appropriateness of a sample size to detect a difference.

Our calculation was: reduction in SSI from 14% to 10% (80% power; alpha 5%) = 2070 participants.

We also followed GRADE guidance and downgraded twice for imprecision when there were very few events and CIs around effects included both appreciable benefit and appreciate harm.

See Characteristics of included studies; Characteristics of excluded studies;Characteristics of studies awaiting classification; Characteristics of ongoing studies for full details of studies identified. We are contacting the authors of three studies to clarify their eligibility for the review (Goharshenasan 2016; Siddiqui 2016; Springer 2015). We identified four relevant on‐going studies (ISRCTN06792113; {"type":"clinical-trial","attrs":{"text":"NCT02771015","term_id":"NCT02771015"}}NCT02771015; {"type":"clinical-trial","attrs":{"text":"NCT02904200","term_id":"NCT02904200"}}NCT02904200; {"type":"clinical-trial","attrs":{"text":"NCT02619773","term_id":"NCT02619773"}}NCT02619773).

In searching trial registers we also located records for four studies marked as complete, which we could not link to published data on the basis of the information available (see Table 11). We have tried to contact representatives for these trials to locate possible unpublished data: this work is ongoing.

Information on studies listed as completed on trial register with unclear publication status

Included studies

A total of 29 RCTs met the inclusion criteria; nine being added in this 2016 update (Biffi 2012; Dickinson Jennings 2015; Kriegar 2011; Langlois 2015; Ozaki 2015; Politano 2011; Prather 2011; Ruiz‐Tovar 2015; Siah 2011). There are now 23 two‐arm trials and six three‐arm trials in the review. Ruiz‐Tovar 2015 was a three‐arm trial, but only two arms are relevant here and we did not extract data for the non‐relevant arm. In one three‐arm trial, two of the three arms were randomised to receive different brands of a film dressing (Cosker 2005). For this review, these two film‐dressing groups were combined into one group and the trial was treated as a two‐arm trial. Likewise, for Dickinson Jennings 2015 we combined two silver dressing arms. We did not combine arms for the remaining three‐arm trials, since all groups were deemed to have received different interventions, and so we included all relevant comparisons.

In all trials the surgical procedure took place in a hospital operating theatre.

In total 15 (52%) of the included trials have been published since 2007 (Bennett 2013; Biffi 2012; Burke 2012; Dickinson Jennings 2015; Kriegar 2011; Langlois 2015; Martin‐Trapero 2013; Ozaki 2015; Politano 2011; Prather 2011; Ravnskog 2011; Ruiz‐Tovar 2015; Shinohara 2008; Siah 2011; Vogt 2007).

The trials took place in several different countries: 17 were conducted in Europe, four in the UK (Cosker 2005; Hewlett 1996; Law 1987; Moshakis 1984), two in Belgium (De Win 1998; Phan 1993); two in Sweden (Persson 1995; Wikblad 1995), two in Denmark (Holm 1998; Vogt 2007), one in Germany (Rohde 1979), one in Ireland (Burke 2012), two in Spain (Martin‐Trapero 2013; Ruiz‐Tovar 2015), one in France (Langlois 2015), one in Italy (Biffi 2012), and one in Norway (Ravnskog 2011). Two of the remaining trials were conducted in Australia (Lawrentschuk 2002; Wynne 2004), one in Pakistan (Gardezi 1983), seven in the USA (Bennett 2013; Dickinson Jennings 2015; Kriegar 2011; Michie 1994; Ozaki 2015; Politano 2011; Prather 2011), one in Japan (Shinohara 2008), and one in Singapore (Siah 2011). One trial was published in German (Rohde 1979), and one in Spanish (Martin‐Trapero 2013), and we acquired translations of these.

The types of surgical procedures undertaken were varied and included cardiac and/or vascular surgery (Shinohara 2008; Vogt 2007; Wikblad 1995; Wynne 2004); caesarean sections (Bennett 2013), abdominal surgery and/or gastrointestinal surgery (Biffi 2012; Holm 1998; Kriegar 2011; Persson 1995; Martin‐Trapero 2013; Rohde 1979), or a number of different surgical procedures within the same trial (Burke 2012; Gardezi 1983; Hewlett 1996; Siah 2011). The surgical procedures in each trial were classified as having been clean, clean/contaminated, contaminated or dirty, or a combination of these (see Table 10 for classification). We recorded when the type of surgery performed was unclear (Rohde 1979). Studies also compared a range of different dressing types and regimens as described below and in Table 12.

Trial data

Excluded studies

In total, we excluded 99 studies after screening of the full text. There were a number of reasons for exclusions including 21 studies that were not RCTs and nine studies that included wounds healing by secondary intention, i.e. wounds that were left open, or had broken open, and were healing from deep to superficial layers. Full details are given in the Characteristics of excluded studies.

For a summary PRISMA flow chart see Figure 1.

See: Table 1; Table 2; Table 3; Table 4; Table 5; Table 6; Table 7; Table 8; Table 9

Basic wound contact dressing compared with exposed wound

Film dressing compared with exposed wound

Silver dressing compared with exposed wound

Basic wound contact dressing compared with film dressing

Basic wound contact dressing compared with hydrocolloid dressing

Basic wound contact dressing compared with fibrous‐hydrocolloid dressing

Basic wound contact dressing compared with polyurethane matrix hydrocolloid dressings

Basic wound contact dressing compared with silver dressing

Basic wound contact dressing compared with non‐silver antimicrobial dressings

A summary of all extracted trial data can be found in Table 12

Wound dressings compared with exposed wounds (no dressing)

Comparison 1: Basic wound contact dressings compared with exposed wound (no dressing) (2 trials; 319 participants)

Two trials, involving a total of 319 participants, compared wound exposure with basic wound contact dressings. Law 1987 conducted a three‐arm trial where the surgical procedure had a 'clean' contamination classification (112 participants). The trial compared a basic wound contact dressing (removed after five days and changed if wound was discharging), with exposed wounds. Phan 1993 undertook a surgical procedure with clean and 'clean/contaminated' contamination classification and compared a basic wound contact dressing (changed twice daily) with exposed wounds that were treated with petroleum jelly (Vaseline).

Primary outcome: SSI

Clean surgery

Law 1987: it is uncertain whether there is a difference in SSI risk between basic wound contact‐dressed wounds (3/59; 5%) and exposed wounds (1/53; 2%) (RR for developing SSI in the exposed group compared with the basic wound contact = 0.37, 95% CI 0.04 to 3.46; Analysis 1.1;very low certainty evidence downgraded once for risk of bias and twice for imprecision,Table 1).

Potentially contaminated surgery
Phan 1993: it is uncertain whether there is a difference in SSIs risk between basic wound contact‐dressed wounds (21/102; 21%) and exposed wounds (29/105; 28%) (RR for developing an SSI in the exposed group compared with the basic wound contact group = 1.34; 95% CI 0.82 to 2.19; Analysis 1.1;very low certainty evidence downgraded once for risk of bias and twice for imprecision,Table 1).

Secondary outcomes

Clean surgery: scarring

Law 1987 reported that there was no difference in quality of final scar between the exposed group and the basic wound contact‐dressed group, but did not present data or was any information regarding who measured this outcome, how it was measured, or how long after surgery. The effect of these interventions on scarring is uncertain (very low certainty evidence downgraded once for risk of bias and twice for imprecision, Table 1).

Clean surgery: acceptability

The trial reported no difference in dressing preference as measured on a linear analogue scale, and presented no further information or data. The effect of these interventions on acceptability is uncertain (very low certainty evidence downgraded once for risk of bias and twice for imprecision, Table 1).

Clean surgery: costs

Law 1987 reported that the mean total dressing costs per participant for the basic wound contact‐dressed group were GBP 6.60 compared with GBP 0.80 in the exposed group. No detailed information was presented i.e. the cost of complications, duration of stay in hospital and nurse time. The cost of dressing data alone is of limited value to decision makers.

Potentially contaminated surgery
Phan 1993 did not present data on secondary outcomes.

Summary: Basic wound contact dressings compared with exposed wounds

It is uncertain whether leaving surgical wounds exposed (no dressing) when healing by primary intention increases or decreases SSI risk compared with use of a basic wound contact dressing following clean surgery or surgery with the potential for contamination; we assessed the certainty of the evidence as very low (downgraded once for risk of bias and twice for imprecision,Table 1).

The effect of these interventions on scarring and acceptability of dressings to patients is also uncertain as the certainty of evidence has been assessed as very low (downgraded once for risk of bias and twice for imprecision). The use of dressings incurs additional unit costs, but there are no cost‐effectiveness data available from these studies to facilitate informed decision making.

Comparison 2: Film dressings compared with exposed wounds (1 trial; 107 participants)

Law 1987 compared an exposed wound with a film‐dressed wound in 107 participants in clean surgery.

Primary outcome: SSI

Clean surgery

Law 1987: it is uncertain whether leaving surgical wounds exposed (1/53; 2%) leads to an increase or decrease in SSI risk compared with film‐dressed wounds (5/54; 9%) (RR 0.20, 95% CI 0.02 to 1.69; Analysis 2.1; very low certainty evidence, downgraded once for risk of bias and twice for imprecision,Table 2).

Secondary outcomes

Clean surgery: scarring

Law 1987 reported that there was no difference in quality of final scar between the exposed group and the film group, but presented no data or any information regarding who measured this outcome, how it was measured, or how long after surgery. The effect of these interventions on scarring is uncertain (very low certainty evidence downgraded once for risk of bias and twice for imprecision, Table 2).

Clean surgery: acceptability

The trial reported no difference in dressing preference as measured on a linear analogue scale. No further information or data were presented. The effect of these interventions on acceptability is uncertain (very low certainty evidence downgraded once for risk of bias and twice for imprecision, Table 2).

Clean surgery: costs

Law 1987: total mean dressing costs per participant for the film group were GBP 42.00 compared with GBP 0.80 in the exposed group.

Summary: Film dressings compared with exposed wound

It is uncertain whether leaving surgical wounds to heal by primary intention exposed (no dressing) following clean surgery increases or reduces SSI risk compared with use of a film dressing; we assessed the certainty of the evidence as very low (downgraded once for risk of bias and twice for imprecision,Table 2). One trial reported that film dressings were more costly than leaving wounds exposed, but there are no cost‐effectiveness data available from the trial to facilitate informed decision making.

Comparison 3: Silver dressings compared with exposed wounds (1 trial; 166 participants)

Siah 2011 compared a silver dressing with wound exposure in 166 participants undergoing various types of elective colorectal surgery which were classed by review authors as clean/contaminated.

Primary outcome: SSI

Potentially contaminated surgery

Siah 2011: it is unclear whether leaving a surgical wound exposed (8/83; 10%) leads to an increase or a decrease in SSI risk compared with a silver‐dressed wound (1/83; 1%). RR: 8.00, 95% 1.02 to 62.55 (Analysis 3.1; very low certainty evidence downgraded once for risk of bias and twice for imprecision,Table 3).

Secondary outcomes

Siah 2011 reported no relevant secondary outcomes.

Summary: Silver dressings compared with exposed wound

It is uncertain whether leaving surgical wounds that are healing by primary intention exposed (no dressing) following surgery at risk of contamination increases or reduces SSI risk compared with use of a silver dressing; we assessed the certainty of the evidence as very low (downgraded once for risk of bias and twice for imprecision,Table 3).

Dressings compared with other types of dressings

Comparison 4: Comparisons between different basic wound contact dressings (1 trial; 50 participants)

Lawrentschuk 2002 undertook a surgical procedure with a 'clean' contamination classification and compared a paraffin tulle dressing with a non‐adherent dressing in 50 participants (25 in each arm). Both dressing types were applied in the same way. In both groups a compressible, combined dressing was placed over the evaluated dressings with an adhesive elastic dressing then placed over these.

Primary outcome: SSI

Clean surgery

Lawrentschuk 2002: There was no clear difference in SSI risk between paraffin tulle‐dressing (0/25; 0%) compared with the non‐adherent dressings (3/25; 12%: RR 0.14, 95% CI 0.01 to 2.63; Analysis 4.1; low certainty evidence ‐ downgraded twice for imprecision); the 95% CI are wide and include both clinical benefit (in terms of reduced SSI risk) and harm (in terms of increased SSI risk).

Summary: Basic wound contact dressings compared with different basic wound contact dressings

It is not clear whether paraffin tulle dressings reduce the risk of SSI events in surgical wounds healing by primary intention following clean surgery compared with use of a non‐adherent dressing; the 95% CI are wide and include both clinical benefit (in terms of reduced SSI risk) and harm (in terms of increased SSI risk) (low certainty evidence; downgraded twice for imprecision).

Comparison 5: Basic wound contact dressings compared with film dressings (8 trials; 1087 participants)

Eight trials compared a basic wound contact dressing with a film dressing. Five of these trials evaluated wounds resulting from 'clean' surgical procedures (Cosker 2005; De Win 1998; Law 1987; Moshakis 1984; Wynne 2004), and three evaluated wounds resulting from surgical procedures with mixed, or unclear, contamination classifications (Gardezi 1983; Hewlett 1996; Rohde 1979). The trials included a variety of basic wound contact dressings including gauze and surgical absorbents. Similarly, whilst the comparators were all film dressings, different brands were evaluated (five trials evaluated Opsite (Smith & Nephew), three Tegaderm (3M Healthcare), and one an unnamed brand (Cosker 2005 evaluated two film dressings).

Primary outcome: SSI

Clean surgery

Using a fixed‐effect model we pooled data from the four trials with participants who had 'clean' surgery and that reported SSI data (Cosker 2005; De Win 1998; Law 1987; Wynne 2004) (Analysis 5.1). One further trial, Moshakis 1984 did not report SSI data. Whilst Law 1987 and Wynne 2004 were three‐arm trials, this was the only meta‐analysis conducted with their data, so the complete groups relevant to this pooling were used. De Win 1998 reported zero SSI events. There is uncertain evidence on the risk of SSI between basic wound contact‐dressed wounds and film‐dressed wounds (RR 1.34; 95% CI 0.70 to 2.55; Analysis 5.1; very low certainty evidence downgraded once for risk of bias and twice for imprecision,Table 4).

Potentially contaminated surgery

Gardezi 1983 conducted several surgical procedures that were classified as clean, clean/contaminated and possibly contaminated. There was no clear evidence of a difference in the risk of SSI in the basic wound contact‐dressed group (6/50; 12%) compared with the film‐dressed group (3/50; 6%) (RR 0.50 95% CI 0.13 to 1.89; Analysis 5.2; very low certainty evidence downgraded once for risk of bias and twice for imprecision;Table 4).

Hewlett 1996: did not report SSI data.

We could not be sure of the surgical classification of one further trial Rohde 1979. In total, 24/46 (52%) of participants in the basic wound contact dressing group had a mild wound infection compared with 14/44 (32%) in the film‐dressed group (RR 0.61; 95% CI 0.36 to 1.02 in favour of the film dressing. Given the difficulty in classifying the type of surgical procedure(s) undertaken in Rohde 1979, we did not pool this trial with Gardezi 1983. Overall it is unclear whether there is a difference in the risk of SSI in surgeries with different levels of potential contamination (very low certainty evidence downgraded once for risk of bias and twice for imprecision;Table 4).

Secondary outcomes

Clean surgery: pain

Moshakis 1984: reported the levels of pain in each group. This was measured using a patient‐assessed linear scale (1 to 10) where 1 corresponded to 'no discomfort' and 10 to 'extremely uncomfortable or painful'. Mean pain levels in the basic wound contact group were 5.1 (SD 2.78) compared with 1.6 (SD 1.48) in the film‐dressed group, favouring film dressings: mean difference (MD ‐3.50; 95% CI ‐4.29 to ‐2.71; Analysis 5.3). We deemed this trial to be at high risk of bias for two domains and it did not take into account the cluster nature of data. Evidence is of very low certainty and all analyses in this trial must be interpreted with caution.

Clean surgery: acceptability

Moshakis 1984: participants and treating nurses were asked to rate their acceptability of the dressings, which were measured using a linear scale where 1 corresponded to 'no trouble' and 10 to 'very troublesome'. The mean response of basic wound contact‐dressed participants was 4.2 (SD 2.46) and the mean response of the film‐dressed group was 1.3 (SD 1.17; (MD ‐2.90; 95% CI ‐3.59 to ‐2.21, favouring the film‐dressed group; Analysis 5.4;very low certainty evidence downgraded twice for risk of bias and once for imprecision;Table 4).

The mean acceptability response of the treating nurse was 5.4 (SD unknown) in the basic wound contact group and 1.2 (SD unknown) in the film group.

Clean surgery: costs

De Win 1998: reported the total mean cost of dressings per participant in Belgian francs (now replaced by the Euro (EUR)): BEL 11.5 in the basic wound contact‐dressed group and BEL 14.3 in the film‐dressed group. No further economic data were presented in this trial. Law 1987 reported the mean per participant cost of the dressings in each group: GBP 6.60 in the basic wound contact group and GBP 42.00 in the film group.

Potentially contaminated surgery: ease of removal

Rohde 1979: also reported figures for ease of dressing removal, but as there was no information about how these data were obtained or what they meant, we cannot interpret them (Table 12).

Potentially contaminated surgery: pain

Gardezi 1983: reported a measure for pain in each group, no details were provided regarding collection of these data or how they could be interpreted (Table 12).

Potentially contaminated surgery: costs

Hewlett 1996: reported the mean per participant cost of dressings (including and excluding procedure pack) as GBP 1.60 for the basic wound contact‐dressed group compared with GBP 1.46 for the film‐dressed group or GBP 4.36 compared with GBP 2.84 when procedure packs were included. Rohde 1979 reported the cost per participant in Deutsch marks (now replaced by EUR) as DEM 10.40 in the basic wound contact‐dressed group and DEM 3.60 in the film group.

Summary: Basic wound contact dressings compared with film dressings

It is uncertain whether covering surgical wounds that are healing by primary intention with a film dressing increases or decreases the risk of SSI compared with use of a basic wound contact dressing following clean surgery or following surgery with other (or uncertain) contamination levels; we assessed the certainty of the evidence as very low (downgraded once for risk of bias and twice for imprecision,Table 4).

It is uncertain whether people with wounds treated with film dressings reported better or worse acceptability compared with basic wound contact dressings (very low certainty evidence downgraded twice for risk of bias and once for imprecision;Table 4). The cost data presented were too limited to allow us to draw any conclusions based on costs versus benefits.

Comparison 6: Basic contract wound dressings compared with hydrocolloid dressings (6 trials; 792 participants)

Six trials investigated the effect of a basic wound contact dressing compared with a hydrocolloid dressing (Holm 1998; Michie 1994; Persson 1995; Shinohara 2008; Wikblad 1995; Wynne 2004). The basic wound contact dressings were predominantly gauze.

Primary outcome: SSI

Clean surgery

Michie 1994: none of the 28 wound halves randomised to the basic wound contact dressing or the hydrocolloid dressing developed an SSI.

Wikblad 1995 presented no clear SSI data. The authors reported that 11 participants were treated with antibiotics postoperatively, and eight of these participants had infections in the sternum (five of these participants were in the basic wound contact dressing group). No further information was provided. We classed this trial as being at a high risk of bias due to a large amount of missing data.

Wynne 2004: it is uncertain whether there is a difference in SSI risk between hydrocolloid‐dressed (6/267; 2%) and basic wound contact‐dressed wounds (6/243; 3%) (RR 0.91; 95% CI 0.30 to 2.78; Analysis 6.1; very low certainty evidence downgraded once for risk of bias and twice for imprecision;Table 5).

Potentially contaminated surgery

We pooled data from all trials in this comparison that presented SSI data (Holm 1998; Persson 1995; Shinohara 2008). It is uncertain whether there is a difference in SSI risk between hydrocolloid‐dressed and basic wound contact‐dressed wounds: (RR 0.57; 95% CI 0.22 to 1.51; I² = 0%; Analysis 6.1; very low certainty evidence downgraded twice for risk of bias and twice for imprecision;Table 5).

Secondary outcomes

Clean surgery: scarring

Michie 1994: participants were asked to assess different aspects of scarring as either: excellent, good or fair. This was a split‐site trial with halves of the same wound randomised to different dressings.

Four weeks postoperatively:

• 22/28 (79%) of participants reporting on the hydrocolloid dressing rated their scar evenness as excellent compared with 14/28 (50%) reporting on the basic wound contact dressing. P value reported by trial authors as 0.008.

• 22/28 (79%) of participants reporting on the hydrocolloid dressing rated their scar colour as excellent compared with 13/28 (46%) reporting on the basic wound contact dressing. P value reported by trial authors as 0.004.

• 21/28 (75%) of participants reporting on the hydrocolloid dressing rated their scar suppleness as excellent compared with 15/28 (54%) reporting on the basic wound contact dressing. P value reported by trial authors as 0.003.

Data for these outcomes were also extracted at a seven‐month visit but are not presented here, as there were more missing data at this later time point. Further scarring assessments by investigators are reported in Table 12

Hydrocolloid dressings may lead to some improvement in cosmetic appearance of scars compared with basic wound contact dressings, but these data were low certainty evidence downgraded twice for imprecision (Table 5).

Clean surgery: pain

Wikblad 1995 reported pain at dressing removal; 76% of participants (raw data calculated by review author as 64/84) in the basic wound contact group reported no pain on removal, compared with 61% (calculated as 37/61) in the hydrocolloid group: RR 0.80; 95% CI 0.63 to 1.01 (Analysis 6.2). However, a large number of participants were missing from this trial, which we classed as being at high risk of bias.

Clean surgery: acceptability

Wynne 2004: in the basic wound contact group 46/243 (19%) of participants reported that they were dissatisfied with the dressing compared with 75/267 (28%) in the hydrocolloid group (RR 1.48; 95% CI 1.07 to 2.05). It is not possible to tell how this dissatisfaction was influenced by the short time for which the basic wound contact dressing was in situ. It was unclear if participants were blinded to treatment. Hydrocolloid dressings may lead to more dressing dissatisfaction compared with basic wound contact dressings, but these data were low certainty evidence, downgraded once risk of bias and once for imprecision, Table 5).

Clean surgery: ease of removal

Wikblad 1995 reported at five days postoperatively that 5/84 (6%) of respondents (clinicians) classified basic wound contact dressings as difficult to remove, compared with 13/61 (21%) in the hydrocolloid group (RR 3.58, 95% CI 1.35 to 9.51).

Michie 1994 reported at three days postoperatively that 22/28 (79%) participants reported that the hydrocolloid dressing was easy to remove compared with 18/28 (64%) who reported that the basic wound contact dressing was easy to remove. This was a split‐site randomised trial.

It is uncertain whether there are differences between hydrocolloid dressings and basic wound contact dressings in terms of ease of removal as the certainty of the evidence has been assessed as very low (downgraded twice for risk of bias, once for imprecision and once for inconsistency;Table 5).

Clean surgery: costs

Wikblad 1995 reported the mean dressing cost per participant at USD 0.73 in the basic wound contact dressing group, and USD 3.60 in the hydrocolloid group.

Wynne 2004 reported the median cost per participant of the basic wound contact dressing group as AUD 0.52, compared with AUD 3.93 for the hydrocolloid group. Again this value included only the cost of the dressings themselves, and not other important measures of resource‐use that should be considered when using cost as a decision tool, i.e. amount of nurse time, and cost of complications.

Potentially contaminated surgery: scarring

Shinohara 2008: The mean scar width for both groups was very similar; 2.3 mm (standard deviation 2.4 mm) in the basic wound contact group compared with 2.2 mm (standard deviation 2.4 mm) in the hydrocolloid group (mean difference ‐0.10, 95% CI ‐0.91 to 0.70). We judged the data to provide low certainty evidence, downgraded once for imprecision and once for indirectness (Table 5).

Holm 1998 also reported the mean width of scars as 2.26 mm (range 1 mm to 5 mm) in the basic wound contact group and 1.78 mm (range 1 mm to 3 mm) in the hydrocolloid group (no standard deviation or related data presented) (Table 5).

Potentially contaminated surgery: pain

Persson 1995 reported participants' perceived pain associated with the wound, measured on a visual analogue scale (VAS) (0 to 100 mm) where a higher score indicted worse pain. The mean score for the basic wound contact group was 40 mm compared with 32 mm in the hydrocolloid group (no standard deviation data presented). We cannot interpret the data further.

Potentially contaminated surgery: costs

Shinohara 2008: reported the mean cost of dressings per patient in the basic wound contact group (in Japanese Yen) as JPY 780, compared with JPY 715 in the hydrocolloid group.

Summary: Basic wound contact dressings compared with hydrocolloid dressings

It is uncertain whether covering surgical wounds healing by primary intention with a hydrocolloid dressing increases or decreases the risk of SSI compared with a basic wound contact dressing following clean surgery (very low certainty evidence, downgraded for once risk of bias and twice for imprecision) or following surgery with other contamination levels (very low certainty evidence downgraded twice for risk of bias and twice for imprecision) (Table 5).

There was some low certainty evidence that hydrocolloid dressings may lead to some improvement in cosmetic appearance of scarring following clean surgery and other surgery types. Conversley there was low certainty evidence that hydrocolloid dressings may lead to more dissatisfaction with the dressing than basic wound contact dressings. It is uncertain whether there are differences between the dressings in terms of ease of dressing removal, as we assessed the certainty of the evidence as very low, (Table 5).

Wikblad 1995 report that a basic wound contact dressing was less painful at removal than a hydrocolloid dressing, but the analysis had a large amount of missing data and we judged it to be at high risk of bias, as well as being imprecise: we assessed the evidence from this trial as being of very low certainty.

Comparison 7: Basic wound contact dressings compared with fibrous‐hydrocolloid (hydrofibre) dressings (3 trials; 364 participants)

Two trials compared a basic wound contact dressing with a hydrofibre dressing (Burke 2012; Vogt 2007). Vogt 2007 randomised 160 participants undergoing elective vascular surgery to either an absorbant dressing or a hydrofibre dressing, while Burke 2012 randomised 124 participants undergoing hip or knee replacement to either an absorbent or a Jubilee dressing. The Jubilee dressing was described as having a hydrofibre inner layer and hydrocolloid outer layer. We considered the hydrofibre layer to be the contact dressing. Langlois 2015 randomised 80 participants undergoing hip or knee replacement to receive a gauze dressing or a hydrofibre dressing.

Primary outcome: SSI

Clean surgery

We included all three studies in this analysis (Burke 2012; Langlois 2015; Vogt 2007). For Vogt 2007 we have used the results of an intention‐to‐treat analysis including withdrawals in the denominator only (did not have an SSI) as our methodology stipulated. We have also presented the raw data reported for reference purposes (Analysis 7.2).

We pooled data from the studies: there was a total of 364 participants, but only one trial had outcome events (Vogt 2007), so the results are driven by this. It is uncertain whether covering surgical wounds that are healing by primary intention with a fibrous hydrocolloid dressing increases or decreases risk of SSI compared with a basic wound dressing following clean surgery, (RR 1.29; 95% CI 0.50 to 3.28; Analysis 7.1; very low certainty evidence downgraded once due to risk of bias and twice due to imprecision;Table 6).

Secondary outcomes

Clean surgery: scarring

Langlois 2015 measured patient satisfaction with appearance of scar in three ways. One was using a VAS for which it was not clear whether a low or high score was better. We have not reported this here. The trial also reported data on a categorical scale (poor, acceptable or excellent) and results of the Stoney Brook scale (see Table 12 for these data). Data are reported as medians with standard deviations (usually used to summarise mean data). Since data have not been presented using the mean or categories we have not analysed them further.

Clean surgery: pain

Langlois 2015 assessed by patients and nurses using a four‐point scale where 1 was `not satisfied'; 2 was `fairly satisfied'; 3 was `satisfied'; and 4 was `highly satisfied' ‐ see Table 12. The data were presented using medians and standard deviations, which means that further analyses within the review are not possible.

Clean surgery: costs

Vogt 2007: while this trial reported the mean cost per participant (which included dressings, nurse time and other equipment, such as gloves), no further information was provided. The per participant cost of the basic wound contact group was reported in Euros as a range spanning EUR 10 to EUR 11.8 compared with EUR 20.3 to EUR 48.7 for the fibrous‐hydrocolloid group.

Burke 2012 reported the mean number of dressing changes for each group, with more participants in the hydrofibre group requiring only one dressing change 61% (38/62), and fewer requiring two dressing changes (31%; 19/62), or three or more dressing changes (8%; 5/62) when compared with the absorbent dressing arm where 56% (35/63) of participants required two dressing changes and 31% (19/62) required three or more dressing changes.

Summary: Basic wound contact dressings compared with fibrous‐hydrocolloid (hydrofibre) dressings

It is uncertain whether covering surgical wounds that are healing by primary intention with a fibrous hydrocolloid dressing increases or decreases risk of SSI compared with a basic wound dressing following clean surgery; we assessed the certainty of the evidence as very low (downgraded once due to risk of bias and twice due to imprecision; Table 6). The cost of fibrous‐hydrocolloid dressings was higher than the cost of basic wound contact dressings, but they may require changing less often.

Comparison 8: Basic wound contact dressings compared with polyurethane matrix hydrocolloid dressings (1 trial; 144 participants (estimated))

Wikblad 1995 was a three‐arm trial, presented in comparison 6. It investigated the effect of a basic wound contact dressing compared with a polyurethane matrix hydrocolloid dressing after heart surgery.

Primary outcome: SSI

Clean surgery

Wikblad 1995 reported no interpretable data for SSI. The authors reported that 11 participants were treated with antibiotics postoperatively, and eight of these had infections in the sternum (of which five were in the basic wound contact dressing group). No further information was provided and the outcome was considered to be unreported (Table 7).

Secondary outcomes

Clean surgery: ease of removal

Wikblad 1995: at five days postoperatively 5/84 (6%) of respondents (clinicians) reported that the basic wound contact dressings were difficult to remove, compared with 45/60 (75%) in the hydrocolloid group (RR 12.60, 95% CI 5.32 to 29.85 (no analysis presented); very low certainty evidence downgraded twice for risk of bias and once for imprecision; Table 7).

Clean surgery: pain

Wikblad 1995 reported pain at dressing removal and ease of removal; 76% of participants (calculated by review author as 64/84) in the basic wound contact dressing group reported no pain on removal, compared with only 14% (calculated by review authors as 8/60) in the hydrocolloid group. Fewer participants in the basic wound contact dressing group reported pain on dressing removal than in the matrix hydrocolloid group (RR 0.17; 95% CI 0.09 to 0.34; Analysis 8.1). A large number of participants were missing from this trial, which we classed as being at a high risk of bias.

Clean surgery: costs

Wikblad 1995 reported the mean dressing cost per patient at USD 0.73 for the basic wound contact dressing group and USD 3.34 for the matrix hydrocolloid group.

Summary: Basic wound contact dressings compared with polyurethane matrix hydrocolloid dressings

It is uncertain whether covering surgical wounds that are healing by primary intention with a polyurethane matrix hydrocolloid dressing increases or decreases the risk of SSI compared with a basic wound contact dressing following clean surgery; we assessed the certainty of the evidence as very low. The only trial to contribute data was poorly reported and at high risk of attrition bias with no SSI outcome data that could be used (Table 7). It was uncertain whether the basic wound contact dressing was easier to remove than the hydrocolloid dressing (very low certainty evidence;Table 7). The unit cost of the hydrocolloid dressing was higher than that of the basic wound contact dressing.

Comparison 9: Basic wound contact dressings compared with silver dressings (8 trials; 1959 participants)

Eight studies were considered in this comparison. Two studies included participants undergoing clean surgery (Dickinson Jennings 2015; Politano 2011). Politano 2011 randomised 145 participants to either a basic wound contact dressing or a silver‐containing dressing. Twenty‐five SSIs were reported in the silver dressing group compared with 19 in the standard dressing group. It was not clear from the report whether these events occurred in separate people, but we have assumed this in our treatment of the data here. Dickinson Jennings 2015 was a three‐arm trial that compared a basic wound dressing to two types of silver dressing. For the purpose of the review, we pooled the silver dressing arms.

Six studies compared the use of a basic wound dressing with a silver‐containing dressing in surgery at risk of contamination. Four studies involved colorectal surgery (Biffi 2012; Kriegar 2011; Prather 2011; Ruiz‐Tovar 2015). Bennett 2013 randomised 524 participants who had undergone a caesarean section; these can be clean, clean/contaminated, contaminated or dirty depending on timing of membrane rupture and other operative conditions ‐ data on the contamination level of the operations was not presented and so we classed it as mixed although it is likely that most operations were clean. Ozaki 2015 randomised 500 people undergoing a non‐emergency surgical procedure for peripheral vascular disease.

Primary outcome: SSI

Clean surgery

We pooled SSI data from the two clean surgery studies using a random‐effects model (I² = 34%; Chi² P value = 0.22). Based on the average effect, it is uncertain whether silver dressings increase or reduce the risk of SSI compared with a basic wound dressing (RR 1.11; 0.47 to 2.62; Analysis 9.1; very low certainty evidence downgraded once for risk of bias and twice for imprecision; Table 8).

Potentially contaminated surgery

We pooled SSI data from the studies where surgery was at risk of contamination using a random‐effects model ( I² = 40%; Chi² P value = 0.15) (Bennett 2013; Biffi 2012; Kriegar 2011; Ozaki 2015; Ruiz‐Tovar 2015). Based on the average effect of silver dressings it is uncertain whether use of silver dressings reduces the risk of SSI after potentially contaminated surgery compared with the basic wound contact dressings (RR 0.83; 95% CI 0.51 to 1.37; Analysis 9.1; very low certainty evidence downgraded twice for risk of bias and twice for imprecision;Table 8).

Secondary outcomes

Clean surgery: pain

Dickinson Jennings 2015 reported pain data for the three trial arms, but no variation data were reported and we have not considered these data further (see Table 12).

Clean surgery: ease of removal

Dickinson Jennings 2015 reported ease of removal data for the two types of silver dressings, but the data were not clear for the comparator group and so are not considered further (see Table 12).

Potentially contaminated surgery: pain

Prather 2011 measured pain using a 0 to 10 scale with 0 being 'no pain' and 10 being 'worst pain'. At baseline the mean pain score in the silver dressing group was 5 and in the gauze group was 5. Subsequent data were presented for each day until day seven when the mean pain score was 4 in the control group and 2 in the silver group. No standard deviation data were presented and no further analysis is presented here.

Potentially contaminated surgery: costs

Bennett 2013 presented the total dressing costs per group. The group total for the basic wound contact group was USD 307 and the total for the silver group was USD 11,080. No standard deviation data were presented and data are not analysed further.

Summary: Basic wound contact dressings compared with silver‐containing dressings

It is uncertain whether covering surgical wounds that are healing by primary intention with a silver‐containing dressing increases or decreases the risk of SSI compared with a basic wound contact dressing following clean surgery (very low certainty evidence downgraded once for risk of bias and twice for imprecision) or following potentially contaminated surgery (very low certainty evidence downgraded twice for risk of bias and twice for imprecision;Table 8). Data for secondary outcomes were very limited.

Comparison 10: Basic wound contact dressing compared with non‐silver antimicrobial dressings (1 trial; 197 participants)

Martin‐Trapero 2013 randomised participants undergoing elective laparoscopic cholecystectomy to a basic wound contact or PHMB antimicrobial dressing.

Primary outcome: SSI

Clean surgery

It is not clear whether there is a difference in SSI risk between the basic wound contact dressing group (5/101; 5%) and the PHMB dressing‐treated group (1/96; 1%), as the 95% CIs are wide and include benefits (in terms of reduced SSI risk) and harms (in terms of increased SSI risks) (RR 0.21, 95% CI 0.03 to 1.77; Analysis 10.1; low certainty evidence downgraded twice due to imprecision; Table 9).

Secondary outcomes

This trial provided no data for our secondary outcomes..

Summary: Basic wound contact dressings compared with non‐silver antimicrobial dressings

It is not clear whether PHMB dressings reduce SSI risk in surgical wounds healing by primary intention compared with a basic wound contact dressing following clean surgery; the 95% CIs are wide and include benefits (in terms of reduced SSI risk) and harms (in terms of increased SSI risks) (low certainty evidence downgraded twice due to imprecision; Table 9).

Comparison 11: Comparisons between advanced dressings (3 trials; 694 participants)

We considered three studies in this comparison (Ravnskog 2011; Wikblad 1995; Wynne 2004). We included two arms of Wynne 2004 (a three‐arm trial): one arm received a film dressing (left in situ for five days) and another a hydrocolloid dressing (also left in situ for five days). Ravnskog 2011 compared an alginate dressing with a hydrofibre dressing in 200 participants undergoing hip replacement. The trial reported only pain data that could be included in this review.

Primary outcome: SSI

Clean surgery

Wikblad 1995 presented no clear data for SSIs.

In Wynne 2004 it was uncertain whether use of a film‐dressing reduces risk of SSI (9/227; 4%) compared with a hydrocolloid‐dressing (6/267; 2%) (RR 0.57; 95% CI 0.20 to 1.57; Analysis 11.1; very low certainty evidence downgraded once due to risk of bias and twice due to imprecision).

Secondary outcomes

Clean surgery: acceptability

Wynne 2004: in the hydrocolloid group 75/267 (28%) of participants reported that they were dissatisfied with the hydrocolloid dressing compared with 80/227 (35%) in the film group (RR 0.80; 95% CI 0.61 to 1.03) (no analysis presented). It was unclear if participants were blinded to treatment.

Clean surgery: ease of removal

In Wikblad 1995 13/61 (21%) respondents (clinicians) in the hydrocolloid group reported that the dressing was not difficult to remove compared with 45/60 (75%) in the matrix hydrocolloid group (RR 3.52, 95% CI 2.13 to 5.82) (no analysis presented). However, a large number of participants were missing from this trial, which was classed as being at high risk of bias and data were imprecise and uncertain (very low certainty evidence).

Clean surgery: pain

Ravnskog 2011 used a VAS scale to measure: pain from the dressing during mobilisation; Itching under the dressing; burning pain under the dressing; discomfort caused by use of the dressing; and pain score at dressing removal. The data from the VAS scale were not clear, so these were not analysed further. Participants were also asked whether they had pain at removal of the dressing. In total 2.1% in the alginate dressing group had experienced pain compared with 15% in the hydrofibre dressing group (numerator and denominator data were not presented in the trial report).

In Wikblad 1995, 14% of participants (calculated by review authors as 8/60) in the hydrocolloid group reported no pain at dressing removal compared with 61% (calculated as 37/61) in the matrix‐hydrocolloid group. However, a large number of participants was missing from this trial, which we classed as being at high risk of bias, and the data are imprecise. The effect of these interventions on pain is uncertain (very low certainty evidence).

Clean surgery: costs

Wikblad 1995 reported the mean dressing cost per participant at USD 3.60 for the hydrocolloid dressing group and USD 3.34 for the matrix hydrocolloid group.

Wynne 2004 reported the median cost of the hydrocolloid dressing group in Australian dollars as AUD 3.93, compared with AUD 1.59 for a film dressing. Again this value included only the cost of the dressings themselves, and not other important measures of resource use that should be considered when using cost as a decision tool, i.e. amount of nurse time, and cost of complications.

Summary: Advanced dressings compared with another advanced dressing

It is uncertain whether covering surgical wounds that are healing by primary intention with a hydrocolloid dressing increases or decreases the risk of SSI compared with a film dressing following clean surgery, as we have assessed the certainty of evidence as very low (downgraded once due to risk of bias and twice due to imprecision). The limited data means that there is uncertainty about whether any one advanced dressing confers better acceptability or usage.

The primary aim of this systematic review was to present and appraise all existing evidence regarding the relative effectiveness of various surgical dressings, including not using a dressing, and using glue as a dressing, on the risk of developing surgical site infections (SSIs) in surgical wounds that are healing by primary intention. We found insufficient evidence that covering surgical wounds with any dressing compared with leaving them exposed influences the subsequent risk of SSI. Similarly there was insufficient evidence on which to base solid conclusions regarding whether any single type of dressing reduces risk of SSIs in wounds resulting from surgery. GRADE assessments of the evidence resulted predominantly in judgements of very low certainty. The studies included in the analyses were small and had low numbers of events. This means that the available evidence had low statistical power and that for most comparisons we could not exclude the possibility that there might be differences in effectiveness; currently, there is not enough information of a high enough certainty to be sure. Some studies were at a high risk of bias and were lacking important details in reports about trial populations or how outcomes were defined and when outcome data were collected.

We included a range of contamination levels for the many trials that investigated 'non clean' surgery, and it was not possible to draw conclusions for each.

For secondary outcomes, there is again uncertainty due to the certainty of the evidence being low or very low. The results of Moshakis 1984 suggested that film dressings might be less painful for patients than other basic wound contact dressings. However, we judged this trial to be at high risk of bias due to inadequate allocation concealment, and the absence of evidence that appropriate statistical procedures had been employed to accommodate the inclusion of some participants as their own controls (bilateral excisions). Wikblad 1995 reported that basic wound contact dressings were significantly less painful on removal than hydrocolloid dressings. However, a large amount of data were missing from this analysis, and we deemed it, too, to be at a high risk of bias. A number of trials suggested that advanced dressings were more expensive than basic wound contact dressings. However, all cost evaluations were very limited, and did not capture all relevant resource‐use data, or consider the costs versus the benefits of treatments ‐ which is best practice in economic evaluation. In short the economic data included in these studies did not lend themselves to decision making.

There are many different dressing options to use postoperatively on surgical wounds. We identified 29 studies to include in this review, these assessed several dressing types, as well as leaving wounds exposed. There are no studies that evaluated glue‐as‐dressing. The included studies reported limited outcome data, even for the primary outcome of SSI. Where SSI was reported, the process used to define infection was often not reported, nor was it clear over what follow‐up period data collection took place. Outcomes for other important patient outcomes such as scarring were also poorly reported, with a range of measures used for assessment, which were sometimes unclear. Frequently, studies were very small in terms of number of participants and outcome events, which meant most included studies were very underpowered. Paradoxically the small, underpowered nature of studies means, that as well as being at risk of type 2 errors (that is missing important differences), they are at increased risk of type I errors as statistically significant findings are more likely to be spurious (Button 2010). Overall, the limited methodological reporting, the small sample sizes and the limited quality of outcome data collection, results in an insufficient volume of potentially biased evidence, which may be selectively reported.

In general, the quality of the studies was very low and difficult to assess due to the lack of methodological detail reported. The majority of the included studies were more than 10 years old and did not follow current trial conduct and reporting guidelines, i.e. CONSORT (Schulz 2010). Key areas of good practice include the robust generation of a randomisation sequence (e.g. by a computer‐generated randomisation schedule); robust allocation concealment (e.g. through the use of a telephone randomisation service); and blinded outcome assessment where this is possible. Blinded outcome assessment is also crucial for assessment of outcomes such as SSI where there may be a subjective element in decision making, as non‐blinded assessment can introduce detection/observer bias (Hróbjartsson 2012), however, blinded assessment was not implemented in six studies, and not clearly reported in 20 more.

Key methodological information should be included in the trial report. In terms of analysis, data from all participants should be included in the analysis whenever possible, i.e. an intention‐to‐treat analysis should be conducted. Steps should be taken during a trial to minimise missing data as far as possible. Where missing data were an issue, imputation methods should be considered and clearly reported when implemented. When studies plan to evaluate more than one wound per person, or use participants as their own controls, or both, they should consult a statistician regarding both the trial design, sample size issues and the more advanced type of analysis that is required and, where possible, robust economic data should be collected. A number of trials included multiple surgical procedures with different levels of potential contamination; since they did not report data for each type separately, this limited the value of the data for analysis.

We conducted a comprehensive search that included trial registries, and obtained translations as required, so we do not believe that language bias is an issue. We were not able to explore publication bias using the studies we had, so the potential for bias for that is unknown. We did not deviate from the prepublished protocol, so do not believe bias has been introduced in terms of selective outcome reporting on our part.

It is noteworthy that we found four studies reported on a trial register (one of these trials was reported on two registers) which we are unable to link to published data. We contacted trial contacts to try to obtain any data we did not have. Where unpublished data exist and are not included in a review, there is an increase in the risk of publication bias.

We are not aware of any other published systematic reviews of dressings for surgical wounds that are healing by primary intention. Another review, however, regarding the use of wound dressings on surgical wounds was conducted as part of the development of a set of UK clinical guidelines addressing the prevention and treatment of SSIs (NICE 2008). This review generally reached similar conclusions to this systematic review. We would like to note, however, that the conclusions of this Cochrane Review are based on additional trials that were not included in the NICE review.

Our review does differ from the NICE review with regard to our use of healing data from Wikblad 1995. We did not utilise the limited infection data that were provided solely in the text of this three‐arm trial (which reported that 11 participants were treated with antibiotics postoperatively; eight had infections in the sternum: five were from the basic wound contact dressing group, but group(s) for the remaining three participants were not specified). The NICE review merged two of the three trial arms (a hydrocolloid‐dressed arm and a film‐dressed arm), and, as we cannot replicate their analysis, its authors may have obtained additional data (they reported six SSIs in the basic wound contact group and two in the merged hydrocolloid/film group). With regard to this trial, the NICE review concluded that: "there is limited evidence to suggest that there is a difference favouring the use of hydrocolloids or 'hydroactive' (film) dressings against the use of absorbent dressings in the prevention of SSI". Our review does not agree with this finding; however, the overall conclusions of the NICE review regarding wound dressings were limited to: "Cover surgical incisions with an appropriate interactive dressing at the end of the operation". The NICE report also conducted its own costing exercise, given that there were no data from the studies that could be used. They concluded that it is important to take into account the additional costs of changing dressings, as well as the initial price of each dressing type, when choosing dressings to use (NICE 2008).

The recent World Health Organisation guideline is supported by a systematic review containing 19 trials ‐ all included here. The review had a narrower remit comparing advanced dressings with standard dressings. The review reports advanced dressings as: Hydrocolloid; Silver‐impregnated Hydroactive and PHMB. The review also reports very low quality evidence for each of these comparisons (Allegranzi 2016). The guideline recommendation, suggests not using advanced dressings in preference to standard dressings on primarily closed surgical wounds for the purpose of preventing SSI and rates the evidence as low quality.

Implications for practice

There is currently insufficient evidence to determine whether covering surgical wounds that are healing by primary intention with wound dressings reduces the risk of surgical site infections (SSIs), or whether any particular type of wound dressing reduces the risk of infections more than another. Our review also failed to demonstrate any clear advantage of one dressing type over another (or wound exposure) for improved scarring, pain control, patient acceptability or ease of removal. It is important to note that many trials in this review were small and of poor quality, and at high or unclear risk of bias. Given the current evidence, decision makers may wish to make wound dressing choices on costs and clinician and patient preference. Additional steps to prevent SSIs can be based on other existing evidence and guidelines, for example the use of hand decontamination and antibiotic prophylaxis (NICE 2008).

Implications for research

There is a lack of high quality research evidence regarding whether choice of wound dressing (or indeed use of wound dressings at all) affects the risk of SSIs in people whose surgical wounds are healing by primary intention. Whilst uncertainty remains regarding the best approach to dressing these surgical wounds, any investment in future research must maximise its value to decision‐makers. Given both the large number of dressing options and surgical procedures, the design of future trials should focus on those surgical procedures at highest risk of SSI, as well as evaluating the dressings or approaches that health professionals use most widely. In addition, as SSIs can be relatively rare events, very large trials are needed in terms of participant numbers. Such epidemiological information is vital to inform dressing trials and will become available through robust, routine data collection. Additionally, there may be value in asking decision‐makers (including patients) what they feel are the most pressing issues, e.g. type of dressing, or duration that a dressing remains in situ, as well as which outcomes are most important, including the ability of different dressings to manage specific symptoms such as absorption of exudate. Such planning means that research resources can be focused to address priorities. Where trials are conducted, good practice guidelines must be followed in their design, implementation and reporting.

Protocol first published: Issue 1, 2000
Review first published: Issue 7, 2011

The authors would like to acknowledge the contribution of peer referees at both the protocol, review and update stage: Andrea Nelson, Joan Webster, Gill Worthy, Laura Bolton, John McCall, Sonya Osborne, Mark Rogers and Jane Nadel. We would also like to thank Elizabeth Royle for copy editing the review and the updated reviews.

#1 MeSH descriptor: [Bandages] explode all trees #2 MeSH descriptor: [Hydrogels] explode all trees #3 MeSH descriptor: [Alginates] explode all trees #4 (dressing* or hydrocolloid* or alginate* or hydrogel* or foam or bead or film or films or tulle or gauze or non‐adherent or non adherent):ti,ab,kw (Word variations have been searched) #5 MeSH descriptor: [Tissue Adhesives] explode all trees #6 MeSH descriptor: [Fibrin Tissue Adhesive] explode all trees #7 tissue next adhesive*:ti,ab,kw (Word variations have been searched) #8 MeSH descriptor: [Cyanoacrylates] explode all trees #9 octylcyanoacrylate*:ti,ab,kw (Word variations have been searched) #10 Dermabond:ti,ab,kw (Word variations have been searched) #11 MeSH descriptor: [Enbucrilate] explode all trees #12 Enbucrilate:ti,ab,kw (Word variations have been searched) #13 butylcyanoacrylate*:ti,ab,kw (Word variations have been searched) #14 MeSH descriptor: [Acrylates] explode all trees #15 acrylate*:ti,ab,kw (Word variations have been searched) #16 MeSH descriptor: [Bucrylate] explode all trees #17 bucrylate*:ti,ab,kw (Word variations have been searched) #18 {or #1‐#17} #19 MeSH descriptor: [Surgical Wound Infection] explode all trees #20 MeSH descriptor: [Surgical Wound Dehiscence] explode all trees #21 (surg* near/5 infect*):ti,ab,kw #22 (surg* near/5 wound*):ti,ab,kw #23 (wound* near/5 infection*):ti,ab,kw #24 (surg* near/5 incision*):ti,ab,kw #25 (surg* near/5 site*):ti,ab,kw #26 {or #19‐#24}

#27 {and #18, #26} in Trials

For the original review, we searched the following electronic databases:

• Cochrane Wounds Specialised Register (searched 10 May 2011);

• The Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2011, Issue 2);

• Ovid MEDLINE (1950 to April Week 4 2011);

• Ovid MEDLINE (In‐Process & Other Non‐Indexed Citations, 9 May, 2011);

• Ovid Embase (1980 to 2011 Week 18);

• EBSCO CINAHL (1982 to 6 May 2011)

The search used is listed below

#1 MeSH descriptor Bandages explode all trees#2 (dressing* or hydrocolloid* or gauze* or hydrogel* or alginate* or "bead" or "foam"):ti,ab,kw #3 (#1 OR #2) #4 MeSH descriptor Surgical Wound Infection explode all trees #5 MeSH descriptor Surgical Wound Dehiscence explode all trees #6 (surg* NEAR/5 infect*):ti,ab,kw #7 (surg* NEAR/5 wound*):ti,ab,kw #8 (wound* near/5 infection*):ti,ab,kw #9 (surg* NEAR/5 incision*):ti,ab,kw #10 (surg* NEAR/5 site*):ti,ab,kw #11 (#4 OR #5 OR #6 OR #7 OR #8 OR #9)

#12 (#3 AND #11)

The Ovid MEDLINE search was combined with the Cochrane Highly Sensitive Search Strategy for identifying randomised trials in MEDLINE: sensitivity‐ and precision‐maximizing version (2008 revision) (Lefebvre 2009). The Ovid EMBASE and EBSCO CINAHL searches were combined with the trial filters developed by the Scottish Intercollegiate Guidelines Network (SIGN) (SIGN 2010). There were no restrictions on the basis of date or language of publication.

1. exp Bandages/

2. exp Hydrogels/

3. exp Alginates/

4. (dressing* or hydrocolloid* or alginate* or hydrogel* or foam or bead or film or films or tulle or gauze or non‐adherent or non adherent).ti,ab.

5. exp Tissue Adhesives/

6. exp Fibrin Tissue Adhesive/

7. tissue adhesive$.mp.

8. exp Cyanoacrylates/

9. octylcyanoacrylate$.mp.

10. Dermabond.mp.

11. exp Enbucrilate/

12. Enbucrilate$.mp.

13. butylcyanoacrylate$.mp.

14. exp Acrylates/

15. acrylate$.mp.

16. exp Bucrylate/

17. bucrylate$.mp.

18. or/1‐17

19. exp Surgical Wound Infection/

20. exp Surgical Wound Dehiscence/

21. (surg* adj5 infection*).ti,ab.

22. (surg* adj5 wound*).ti,ab.

23. (wound* adj5 infection*).ti,ab.

24. surgical site*.mp.

25. or/19‐24

26. randomised controlled trial.pt.

27. controlled clinical trial.pt.

28. randomi?ed.ab.

29. placebo.ab.

30. clinical trials as topic.sh.

31. randomly.ab.

32. trial.ti.

33. or/26‐32

34. exp animals/ not humans.sh.

35. 33 not 34

36. and/18,25,35

1. exp Wound Dressing/

2. exp Hydrogel/

3. exp Alginic Acid/

4. (dressing* or hydrocolloid* or alginate* or hydrogel* or foam or bead or film or films or tulle or gauze or non‐adherent or non adherent).ti,ab.

5. exp Tissue Adhesive/

6. exp Fibrin Glue/

7. (tissue adj adhesive$).mp.

8. exp Cyanoacrylate Derivative/

9. exp Cyanoacrylic Acid Octyl Ester/

10. octylcyanoacrylate$.mp.

11. Dermabond.mp.

12. exp ENBUCRILATE/

13. enbucrilate.mp.

14. butylcyanoacrylate$.mp.

15. exp Acrylic Acid/

16. acrylate$.mp.

17. exp Bucrilate/

18. bucrylate$.mp.

19. or/1‐18

20. exp Surgical Wound Infection/

21. exp Wound Dehiscence/

22. (surg* adj5 infection*).ti,ab.

23. (surg* adj5 wound*).ti,ab.

24. (wound* adj5 infection*).ti,ab.

25. surgical site*.ti,ab.

26. or/20‐25

27. Randomized controlled trials/

28. Single‐Blind Method/

29. Double‐Blind Method/

30. Crossover Procedure/

31. (random$ or factorial$ or crossover$ or cross over$ or cross‐over$ or placebo$ or assign$ or allocat$ or volunteer$).ti,ab.

32. (doubl$ adj blind$).ti,ab.

33. (singl$ adj blind$).ti,ab.

34. or/27‐33

35. exp animals/ or exp invertebrate/ or animal experiment/ or animal model/ or animal tissue/ or animal cell/ or nonhuman/

36. human/ or human cell/

37. and/35‐36

38. 35 not 37

S34 S13 AND S21 AND S33

S33 S22 or S23 or S24 or S25 or S26 or S27 or S28 or S29 or S30 or S31 or S32

S32 TX allocat* random*

S31 (MH "Quantitative Studies")

S30 (MH "Placebos")

S29 TX placebo*

S28 TX random* allocat*

S27 (MH "Random Assignment")

S26 TX randomi* control* trial*

S25 TX ( (singl* n1 blind*) or (singl* n1 mask*) ) or TX ( (doubl* n1 blind*) or (doubl* n1 mask*) ) or TX ( (tripl* n1 blind*) or (tripl* n1 mask*) ) or TX ( (trebl* n1 blind*) or (trebl* n1 mask*) )

S24 TX clinic* n1 trial*

S23 PT Clinical trial

S22 (MH "Clinical Trials+")

S21 S14 or S15 or S16 or S17 or S18 or S19 or S20

S20 TI (postoperative* N5 infection* OR post‐operative* N5 infection*) or AB (postoperative* N5 infection* OR post‐operative* N5 infection*)

S19 TI wound* N5 infection* or AB wound* N5 infection*

S18 TI surg* N5 wound* or AB surg* N5 wound*

S17 TI surg* N5 infection* or AB surg* N5 infection*

S16 (MH "Surgical Wound")

S15 (MH "Surgical Wound Dehiscence")

S14 (MH "Surgical Wound Infection")

S13 S1 OR S2 OR S3 OR S4 OR S5 OR S6 OR S7 OR S8 OR S9 OR S10 OR S11 OR S12

S12 TI Dermabond or AB Dermabond

S11 TI enbucrilate or AB enbucrilate

S10 TI bucrylate* or AB bucrylate*

S9 TI acrylate* or AB acrylate*

S8 TI butylcyanoacrylate* or AB butylcyanoacrylate*

S7 TI octylcyanoacrylate* or AB octylcyanoacrylate*

S6 TI cyanoacrylate* or AB cyanoacrylate*

S5 TI tissue adhesive* or AB tissue adhesive*

S4 (MH "Fibrin Tissue Adhesive")

S3 TI ( dressing* or pad or pads or gauze or tulle or film or bead or foam* or non‐adherent or non adherent or hydrocolloid* or alginat* or hydrogel* ) or AB ( dressing* or pad or pads or gauze or tulle or film or bead or foam* or non‐adherent or non adherent or hydrocolloid* or alginat* or hydrogel* )

S2 (MH "Alginates")

S1 (MH "Bandages and Dressings+")

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 provided to permit a judgement of low or high risk of bias.

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: use of an open random allocation schedule (e.g. a list of random numbers); assignment envelopes without appropriate safeguards (e.g. envelopes were unsealed, non‐opaque, or not sequentially numbered); alternation or rotation; date of birth; case record number; any other explicitly unconcealed procedure.

Unclear

Insufficient information provided to permit a 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.

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

Either of the following:

• Insufficient information to permit judgement of low or high risk of bias.

• The study did not address this outcome.

Low risk of bias

Any one of the following:

• No missing outcome data.

• Reasons for missing outcome data are unlikely to be related to true outcome (for survival data, censoring unlikely to be introducing bias).

• Missing outcome data are 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 the observed event risk is not enough to have a clinically relevant impact on the intervention effect estimate.

• For continuous outcome data, a plausible effect size (difference in means or standardised difference in means) among missing outcomes is not enough to have a clinically relevant impact on the 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 are likely to be related to the true outcome, with either an imbalance in numbers or reasons for missing data across intervention groups.

• For dichotomous outcome data, the proportion of missing outcomes compared with the observed event risk is enough to induce clinically relevant bias in the intervention effect estimate.

• For continuous outcome data, a plausible effect size (difference in means or standardised difference in means) among missing outcomes is enough to induce a clinically relevant bias in the observed effect size.

• 'As‐treated' analysis done with a substantial departure of the intervention received from that assigned at randomisation.

• Potentially inappropriate application of simple imputation.

Unclear

Either of the following:

• Insufficient reporting of attrition/exclusions to permit a 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.

Low risk of bias

Either of the following:

• The study protocol is available and all of the study’s prespecified (primary and secondary) outcomes that are of interest in the review have been reported in the prespecified way.

• The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were prespecified (convincing text of this nature may be uncommon).

High risk of bias

Any one of the following:

• Not all of the study’s prespecified primary outcomes have been reported.

• One or more primary outcomes is/are reported using measurements, analysis methods, or subsets of the data (e.g. subscales) that were not prespecified.

• One or more reported primary outcomes was/were not prespecified (unless clear justification for their reporting is provided, such as an unexpected adverse effect).

• One or more outcomes of interest in the review is/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 provided to permit a judgement of low or high risk of bias. It is likely that the majority of studies will fall into this category.

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

• 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.

New search for studies and content updated (no change to conclusions)

Basic wound contact dressings compared with exposed wounds

Basic wound contact dressings compared with hydrocolloid dressings

Basic wound contact dressings compared with matrix hydrocolloid dressings

Basic wound contact dressings compared with silver dressings

Bennett 2013

Biffi 2012

Burke 2012

Cosker 2005

De Win 1998

Dickinson Jennings 2015

Gardezi 1983

Hewlett 1996

Holm 1998

Kriegar 2011

Langlois 2015

Law 1987

Lawrentschuk 2002

Martin‐Trapero 2013

Michie 1994

Moshakis 1984

Ozaki 2015

Persson 1995

Phan 1993

Politano 2011

Prather 2011

Ravnskog 2011

Rohde 1979

Ruiz‐Tovar 2015

Shinohara 2008

Siah 2011

Vogt 2007

Wikblad 1995

Wynne 2004

Goharshenasan 2016

Siddiqui 2016

Springer 2015

ISRCTN06792113

As a result of feedback from the peer referees the title of this review has been changed from: Wound dressings for surgical sites; to: Dressings for the prevention of surgical site infection.

Jo Dumville co‐ordinated the review, extracted data and checked the quality of data extraction, undertook and checked quality assessment, analysed and interpreted data,  performed and checked the quality of the statistical analysis, completed the first draft of the review, performed part of the writing or editing, made an intellectual contribution to the review, approved the final version prior to submission, wrote to trial authors/experts/companies and is guarantor for the review and the review update.

Trish Gray contributed to the previous update of this review, checked the quality of data extraction, undertook and checked quality assessment, and checked quality of statistical analysis, performed part of the writing or editing, made an intellectual contribution to the review update, and approved the final version of the review update prior to submission.

Catherine Walter performed previous work that was the foundation of the current review.

Catherine Sharp performed previous work that was the foundation of the current review.

Tamara Page performed previous work that was the foundation of the current review.

Rhiannon Macefield contributed to the update of this review, checked the quality of data extraction, undertook and checked quality assessment, and checked quality of statistical analysis, performed part of the writing or editing, made an intellectual contribution to the review update, and approved the final version of the review update prior to submission.

Natalie Blencowe contributed to the update of this review, checked the quality of data extraction, undertook and checked quality assessment, performed part of the writing or editing, made an intellectual contribution to the review update, and approved the final version of the review update prior to submission.

Thomas KG Milne contributed to the update of this review, checked the quality of data extraction, undertook and checked quality assessment, made an intellectual contribution to the review update, and approved the final version of the review update prior to submission.

Barnaby Reeves contributed to the update of this review, checked the eligibility of additional studies, performed part of the writing or editing, made an intellectual contribution to the review update, and approved the final version of the review update prior to submission.

Jane Blazeby contributed to the update of this review, checked the quality of data extraction, performed part of the writing or editing, made an intellectual contribution to the review update, and approved the final version of the review update prior to submission.

Nicky Cullum (Editor): edited the review and the updated reviews, advised on methodology, interpretation and review content. Approved the final review and the updated reviews prior to submission. Gill Rizzello and Sally Bell‐Syer (Managing Editors) : co‐ordinated the editorial process. Edited the review and updated reviews.

Ruth Foxlee designed the search strategy and Reetu Child ran the searches for this updated review.

• Royal Adelaide Hospital, Adelaide, South Australia, Australia.

• Division of Nursing, Midwifery & Social Work, School of Health Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK.

• This project was supported by the National Institute for Health Research, via Cochrane Infrastructure and Programme Grant funding (NIHR Cochrane Programme Grant 13/89/08 ‐ High Priority Cochrane Reviews in Wound Prevention and Treatment) to Cochrane Wounds. The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the Systematic Reviews Programme, NIHR, NHS or the Department of Health, UK.

• The National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care (NIHR CLAHRC) Greater Manchester, UK.

Jo Dumville: I receive research funding from the NIHR for the production of systematic reviews focusing on high priority Cochrane reviews in the prevention and treatment of wounds.

Trish Gray: none known

Catherine J Walter: none known.

Catherine Sharp: none known.

Tamara Page: none known.

Rhiannon Macefield: none known.

Natalie Blencowe: none known.

Thomas KG Milne: none known.

Barnaby Reeves is funded (both part salary and research consumables) in part by the NIHR Bristol Cardiovascular Biomedical Research Unit.

Jane Blazby: none known.

References to studies included in this review

Bennett 2013 {published data only}

• Bennett K, Kellett W, Braun S, Spetalnick B, Huff B, Slaughter J, et al. Silver ion‐eluting dressings for prevention of post cesarean wound infection: a randomized, controlled trial. American Journal of Obstetrics and Gynecology 2013;208(Suppl 1):337. [Google Scholar]

Biffi 2012 {published data only}

• Biffi R, Fattori L, Bertani E, Radice D, Rotmensz N, Misitano P, et al. Surgical site infections following colorectal cancer surgery: a randomized prospective trial comparing common and advanced antimicrobial dressing containing ionic silver. World Journal of Surgical Oncology 2012;10:94. [PMC free article] [PubMed] [Google Scholar]

Burke 2012 {published data only}

• Burke NG, Green C, McHugh G, McGolderick N, Kilcoyne C, Kenny P. A prospective randomised study comparing the jubilee dressing method to a standard adhesive dressing for total hip and knee replacements. Journal of Tissue Viability 2012;21:84‐7. [PubMed] [Google Scholar]

Cosker 2005 {published data only}

• Cosker T, Elsayed S, Gupta S, Mendonca AD, Tayton KJ. Choice of dressing has a major impact on blistering and healing outcomes in orthopaedic patients. Journal of Wound Care 2005;14(1):27‐9. [PubMed] [Google Scholar]

De Win 1998 {published data only}

• Win M, Blaere X, Scheers R. The effect of choice of surgical wound dressing on the direct cost of healing. Eighth European Conference on Advances in Wound Management, 1998 April 26‐28; Madrid, Spain. Madrid, 1998:54–7.

Dickinson Jennings 2015 {published data only}

• Dickinson Jennings C, Culver Clark R, Baker JW. A prospective, randomized controlled trial comparing 3 dressing types following sternotomy. Ostomy Wound Management 2015;61:42‐9. [PubMed] [Google Scholar]

Gardezi 1983 {published data only}

• Gardezi SA, Chaudhary AM, Sial AK, Ahmad I, Rashid M. Role of 'polyurethane membrane' in post operative wound management. The Journal of the Pakistan Medical Association 1983;33:219‐22. [PubMed] [Google Scholar]

Hewlett 1996 {published data only}

• Hewlett L. The evaluation of two post‐operative dressings in the management of surgical wounds. Fifth European Conference on Advances in Wound Management, 1995 November 21‐24; Harrogate, UK. 1996.

Holm 1998 {published data only}

• Holm C, Petersen JS, Gronboek F, Gottrup F. Effects of occlusive and conventional gauze dressings on incisional healing after abdominal wounds. European Journal of Surgery 1998;164:179‐83. [PubMed] [Google Scholar]

Kriegar 2011 {published data only}

• Krieger BR, Davis DM, Sanchez JE, Mateka JJ, Nfonsam VN, Frattini JC, et al. The use of silver nylon in preventing surgical site infections following colon and rectal surgery. Diseases of the Colon and Rectum 2011;54:1014‐9. [PubMed] [Google Scholar]

Langlois 2015 {published data only}

• Langlois J, Zaoui A, Ozil C, Courpied J‐P, Anract P, Hamadouche M. Randomized controlled trial of conventional versus modern surgical dressings following primary total hip and knee replacement. International Orthopaedics 2015;39:1315‐9. [PubMed] [Google Scholar]

Law 1987 {published data only}

Lawrentschuk 2002 {published data only}

• Lawrentschuk N, Falkenburg MP, Pirpiris M. Wound blisters post hip surgery: a prospective trial comparing dressings. Australian and New Zealand Journal of Surgery 2002;72:716‐9. [PubMed] [Google Scholar]

Martin‐Trapero 2013 {published data only}

• Martin‐Trapero C, Martin‐Torrijos M, Fernandez‐Conde L, Torrijos‐Torrijos M, Manzano‐Martin E, Pacheco‐del Cerro JL, et al. Surgical site infections. Effectiveness of polyhexamethylene biguanide wound dressings. Enfermeria Clinica 2013;23:56‐61. [PubMed] [Google Scholar]

Michie 1994 {published data only}

• Michie DD, Hugill JV. Influence of occlusive and impregnated gauze dressings on incisional healing: a prospective randomized, controlled study. Annals of Plastic Surgery 1994;32:57‐64. [PubMed] [Google Scholar]

Moshakis 1984 {published data only}

• Moshakis V, Fordyce MJ, Griffiths JD, McKinna JA. Tegadern versus gauze dressing in breast surgery. British Journal of Clinical Practice 1984;38:149‐52. [PubMed] [Google Scholar]

Ozaki 2015 {published data only}

• Ozaki CK, Hamdan AD, Barshes NR, Wyers M, Hevelone ND, Belkin M, et al. Prospective, randomized, multi‐institutional clinical trial of a silver alginate dressing to reduce lower extremity vascular surgery wound complications. Journal of Vascular Surgery 2015;61:419‐27. [PubMed] [Google Scholar]

Persson 1995 {published data only}

• Persson M, Svenberg T, Poppen B. To dress or not to dress surgical wounds? Patients' attitudes to wound care after major abdominal operations. European Journal of Surgery 1995;161:791‐3. [PubMed] [Google Scholar]

Phan 1993 {published data only}

• Phan M, Auwera P, Andry G, Aoun M, Chantrain G, Deramaecker R, et al. Wound dressing in major head and neck cancer surgery: a prospective randomised study of gauze dressing vs sterile vaseline ointment. European Journal of Surgical Oncology 1993;19:10–6. [PubMed] [Google Scholar]

Politano 2011 {published data only}

• Politano A, Tracci M, Strider D, Sawyer R, Kern J, Upchurch G, et al. A randomized, prospective study of surgical site infections following vascular reconstructive surgery: untreated vs. silver‐impregnated dressings. 34th Annual Meeting of the Surgical Infection Society, 2014 May 1‐3; Baltimore (MD). 2014.

Prather 2011 {published data only}

• Prather AD, Mateka JJ, Marcet JE. Silver nylon wound dressings are associated with decreased post‐operative pain. Diseases of the Colon and Rectum 2011;45:5. [Google Scholar]

Ravnskog 2011 {published data only}

• Ravnskog FA, Espehaug B, Indrekvam K. Randomised clinical trial comparing Hydrofiber and alginate dressings post‐hip replacement. Journal of Wound Care 2011;20:136‐42. [PubMed] [Google Scholar]

Rohde 1979 {published data only}

• Rohde H, Thon K, Stoltzing H, Schirren J. The transparent adhesive drape as post‐operative dressing ‐ a randomised clinical study for comparison with a conventional dressing [Die Klarsicht‐Klebefolie als postoperativ Verband ‐ eine randomisierte, klinische Studie zum Vergleich mit einer konventionellen Verbandstechnik]. Der Chirurg 1981;52:46‐50. [PubMed] [Google Scholar]

Ruiz‐Tovar 2015 {published data only}

• Ruiz‐Tovar J, Llavero C, Morales V, Gamallo C. Total occlusive ionic silver‐containing dressing vs mupirocin ointment application vs conventional dressing in elective colorectal surgery: effect on incisional surgical site infection. Journal of the American College of Surgeons 2015;221:424‐9. [PubMed] [Google Scholar]

Shinohara 2008 {published data only}

• Shinohara T, Yamashita Y, Satoh K, Mikami K, Yamauchi Y, Hoshino S, et al. Prospective evaluation of occlusive hydrocolloid dressing regarding the healing effect after abdominal operations: randomised controlled trial. Asian Journal of Surgery 2008;31(1):1–5. [PubMed] [Google Scholar]

Siah 2011 {published data only}

• Siah CJ, Bacani CP, Yatim J. Effectivess of total occlusive ionic silver contained dressing in reducing bacterial growth and incidences of surgical site infections following open abdominal surgery‐a randomised controlled trial. Proceedings of Singapore Healthcare. 2011:193.
• Siah CJ, Yatim J. Efficacy of a total occlusive ionic silver‐containing dressing combination in decreasing risk of surgical site infection: an RCT. Journal of Wound Care 2011;20:561‐8. [PubMed] [Google Scholar]

Vogt 2007 {published data only}

• Vogt KC, Uhlyarik M, Schroeder TV. Moist wound healing compared with standard care of treatment of primary closed vascular surgical wounds: a prospective randomized controlled trial. Wound Repair and Regeneration 2007;15:624‐7. [PubMed] [Google Scholar]

Wikblad 1995 {published data only}

• Wikblad K, Anderson B. A comparison of three wound dressings in patients undergoing heart surgery. Nursing Research 1995;44(5):312‐6. [PubMed] [Google Scholar]

Wynne 2004 {published data only}

• Wynne R, Botti M, Stedman H, Holsworth L, Harinos M, Flavell O, et al. Effect of three wound dressings on infection, healing comfort, and cost in patients with sternotomy wounds: a randomised trial. Chest 2004;125(1):43‐9. [PubMed] [Google Scholar]

References to studies excluded from this review

Abejon 2012 {published data only}

• Abejon A. The management of surgical wound: importance of the dressing. European Wound Management Association Journal 2012;12:129. [Google Scholar]

Abejon 2013 {published data only}

• Abejón A, Casanova PL, Verdú SJ, Torra I, Bou J‐E. Open‐label clinical trial comparing the clinical and economic effectiveness of using a polyurethane film surgical dressing with gauze surgical dressings in the care of post‐operative surgical wounds. International Wound Journal 2013;12:285‐92. [PMC free article] [PubMed] [Google Scholar]

Ajao 1977 {published data only}

• Ajao OG. Surgical wound infection: a comparison between dressed and undressed wounds. Journal of Tropical Medicine and Hygiene 1977;80:192‐6. [PubMed] [Google Scholar]

Al‐Belasy 2003 {published data only}

• Al‐Belasy FA, Amer MZ. Hemostatic effect of n‐butyl‐2‐cyanoacrylate (histoacryl) glue in warfarin‐treated patients undergoing oral surgery. Journal of Oral and Maxillofacial Surgery 2003;61(12):1405‐9. [PubMed] [Google Scholar]

Allan 1996 {published data only}

• Allen RB, Kerstein M, Klassen H, Friedmann PS, Pryce DW, Lawrence JC, et al. Prospective study of clinical infections in wounds dressed with occlusive versus conventional dressings. Ninth Annual Symposium on Advanced Wound Care and Sixth Annual Medical Research Forum on Wound Repair, 1996 April 20‐24; Atlanta (GA). 1996:116.

Alsbjorn 1990 {published data only}

• Alsbjorn BF, Ovesen H, Walther‐Larsen S. Occlusive dressing versus petroleum gauze on drainage wounds. Acta Chirurgica Scandinavica 1990;156(3):211‐3. [PubMed] [Google Scholar]

Anonymous 2013 {published data only}

• Anonymous. SiiverSeal® dressing improves surgical wound outcomes. Wounds 2013;25:A18. [Google Scholar]

Baker 1977 {published data only}

• Baker H, Barnes RW, Shurr DG. The healing of below‐knee amputations: a comparison of soft and plaster dressing. American Journal of Surgery 1977;133(6):716‐8. [PubMed] [Google Scholar]

Blondeel 2004 {published data only}

• Blondeel PN, Murphy JW, Debrosse D, Nix II, Puls LE, Theodore N, Coulthard P. Closure of long surgical incisions with a new formulation of 2‐octylcyanoacrylate tissue adhesive versus commercially available methods. American Journal of Surgery 2004;188:307‐13. [PubMed] [Google Scholar]

Borgognoni 2000 {unpublished data only}

• Borgognoni L, Martini L, Brandani P, Pelliccia L, Reali UM. The use of silicone gel sheeting in the prevention of recurrence after keloid excision: a clinical and immunohistochemical investigation. Wound Repair and Regeneration 2000;8(5):A408‐A409. [Google Scholar]

Borkar 2011 {published data only}

• Borkar NB, Khubalkar MV. Are postoperative dressings necessary?. Journal of Wound Care 2011;20:301‐3. [PubMed] [Google Scholar]

Boyce 1995 {published data only}

• Boyce DE, Miller L, Moore K, Harding KG. An open comparative randomized parallel‐group clinical trial to evaluate the performance of Hyaff[TM] wound dressing in the management of pilonidal sinus excision wounds: an interim analysis. Sixth European Conference on Advances in Wound Management; 1995 November 21‐24; Harrogate, UK. 1997:55‐6.

Brehant 2009 {published data only}

• Brehant O, Pessaux P, Regenet N, Tuech JJ, Panaro F, Mantion G, et al. Healing of stoma orifices: multicenter, prospective, randomized study comparing calcium alginate mesh and polyvidone iodine mesh. World Journal of Surgery  2009;33:1795‐801. [PubMed] [Google Scholar]

Cabrales 2014 {published data only}

• Cabrales RA, Cobo RB, Patino YD, Quintero MF, Martinez JW, Upegui ML. Effectiveness of silver dressings in preventing surgical site infection in contaminated wounds. Latreia 2014;27:247‐54. [Google Scholar]

Choi 2005 {published data only}

• Choi JW, Hyun KB, Kim YO, Park BY. Comparing conventional suture method versus wound closure using tissue glue (Histoacryl Blue®): a prospective randomised clinical trial. Journal of the Korean Society for Plastic and Reconstructive Surgery 2005;32(1):19‐23. [Google Scholar]

Chou 2010 {published data only}

• Chou D, Cheng J, Chesnut R, Choudhri H, Gopinath S, Scott Graham R, et al. A prospective, multi‐center, randomized controlled study to compare a low swell formulation of a PEG hydrogel spinal sealant as an adjunct to sutured dural repair with common dural sealing methods. Fifth Annual Meeting of the North American Spine Society. 2010.

Chrintz 1989 {unpublished data only}

• Chrintz H, Vibits H, Cordtz TO, Harreby JS, Waaddegaard P, Larsen SO. Discontinuing postoperative wound dressings [Seponering af postoperativ sarforbinding]. Ugeskrift for Laeger 1989;151(41):2667‐8. [PubMed] [Google Scholar]
• Chrintz H, Vibits H, Cordtz TO, Harreby JS, Waaddegaard P, Larsen SO. Need for surgical wound dressing. British Journal of Surgery 1989;76:204‐5. [PubMed] [Google Scholar]

Colom Majan 2002 {published data only}

• Colom Majan JI. Treatment with a self‐adherent soft silicone gel dressing versus no treatment on postoperative scars. Twelfth Conference of the European Wound Management Association, 2002 May 23‐25; Granada, Spain. 2002.

Decaillet 1998 {published data only}

• Decaillet JM. Use of a new hydrocolloid dressing on sutured wounds after hand surgery. Eighth Conference of the European Wound Management Association, 1998 April, Madrid, Spain. 1998.

Dell 2001 {published data only}

• Dell SJ, Hovanesian JA, Raizman MB, Crandall AS, Doane J, Snyder M. Randomized comparison of postoperative use of hydrogel ocular bandage and collagen corneal shield for wound protection and patient tolerability after cataract surgery. Journal of Cataract and Refractive Surgery 2011;37:1113‐21. [PubMed] [Google Scholar]

Dillon 2008 {published data only}

• Dillon J, Sayer R, Clarke J, McLean I. Evaluation of a hydrofibre/hydrocolloid dressing in a district general hospital. European Wound Management Association Journal 2008;2(Supp):263, Abstract P320. [Google Scholar]

Di Maggio 1994 {published data only}

• Maggio MR, Sakamoto N, Curutchet HP. Comparative study of the evolution of surgical wounds treated with conventional healing topical agents or silicone oil [Estudio comparativo de la evolucion de las heridas quirurgicas cubiertas con curacion convencional o con aceite de siliconas]. La Prensa Médica Argentina 1994;81:194‐6. [Google Scholar]

Dixon 2006 {published data only}

• Dixon AJ, Dixon MP, Dixon JB. Randomized clinical trial of the effect of applying ointment to surgical wounds before occlusive dressing. British Journal of Surgery 2006;93:937‐43. [PubMed] [Google Scholar]

Dobbelaere 2015 {published data only}

• Dobbelaere A, Schuermans N, Smet S, Straeten C, Victor J. Comparative study of innovative postoperative wound dressings after total knee arthroplasty. Acta Orthopedia Belgium 2015;81:454‐61. [PubMed] [Google Scholar]

Dosseh Ekoue 2008 {published data only}

• Dosseh Ekoue D, Doleaglenou A, Fortey YK, Ayite AE. Randomized trial comparing dressing to no dressing of surgical wounds in a tropical setting [Pansement versus absence de pansement au‐delà de 48 heures en milieu tropical: essai randomisé]. Journal de Chirurgie 2008;145(2):143–6. [PubMed] [Google Scholar]

Edwards 1967 {published data only}

• Edwards RH, Killen DA. Comparison of two methods of management of clean surgical wounds. JAMA 1967;201(1):137‐8. [PubMed] [Google Scholar]

Eymann 2010 {published data only}

• Eymann R, Kiefer M. Glue instead of stitches: a minor change of the operative technique with a serious impact on the shunt infection rate. Acta Neurochirurgica. Supplement 2010;106:87‐9. [PubMed] [Google Scholar]

Fries 2014 {published data only}

• Fries CA, Ayalew Y, Penn‐Barwell JG, Porter K, Jeffery SL, Midwinter MJ. Prospective randomised controlled trial of nanocrystalline silver dressing versus plain gauze as the initial post‐debridement management of military wounds on wound microbiology and healing. Injury 2014;45:1111‐6. [PubMed] [Google Scholar]

Furrer 1993 {published data only}

• Furrer M, Inderbitzi R, Nachbur B. Does administration of fibrin glue prevent development of lymphoceles after radical lymphadenectomy?. Der Chirurg 1993;64(12):1044‐9. [PubMed] [Google Scholar]

Garne 1989 {published data only}

• Garne E, Merrild DB. Wound Infection following heart surgery. Ugeskrift for Laeger 1989;151:2192–3. [PubMed] [Google Scholar]

Gbolahan 2015 {published data only}

• Gbolahan OO, Ogunmuyiwa SA, Osinaike BB. Randomized controlled trial comparing dressing and no dressing of surgical wound after cleft lip repair. American Journal of Critical Care 2015;16:554‐8. [PubMed] [Google Scholar]

Giri 2004 {published data only}

• Giri P, Kanti Das M, Majumdar A. Management of different types of wound by cyanoacrylate glue fixation: a random study of 213 patients. Journal of the Indian Medical Association 2004;102(11):625‐6. [PubMed] [Google Scholar]

Gonzalez 2002 {published data only}

• Gonzalez Llinares RM, Antolin Mugarza A, Salgado Larrea MV, Barandiaran Mugica MJ, Basurco Celaya R, Larranaga Garaikaoetxea N. Effectiveness of dressings in clean and clean‐contaminated surgical wounds 24‐48 hours after surgery. Enfermeria Clinica 2002;2:117‐21. [Google Scholar]

Grauhan 2010 {published data only}

• Grauhan O, Navasardyan A, Hofmann M, Muller P, Hummel M, Hetzer R. Cyanoacrylate‐sealed Donati suture for wound closure after cardiac surgery in obese patients. Interactive Cardiovascular and Thoracic Surgery 2010;11(6):763‐7. [PubMed] [Google Scholar]

Grover 2015 {published data only}

• Grover A, Singh A, Sidhu DS. A prospective randomised trial of open wound treatment vs occlusive dressings in elective surgical cases with respect to surgical site infections. Journal of Clinical and Diagnostic Research 2015;9:PC26‐9. [PMC free article] [PubMed] [Google Scholar]

Guilbaud 1993 {published data only}

• Guilbaud J, Honde C. Multicentre comparative clinical study of a new wound dressing: PA286 (Inerpan). European Journal of Plastic Surgery. 1993;16(2):73‐6. [Google Scholar]

Guillotreau 1996 {published data only}

• Guillotreau J, Flandrin Andre P, Moncade F. Calcium alginate and povidone iodine packs in the management of infected postoperative wounds: results of a randomized study [abstract]. British Journal of Surgery 1996;83:86. [Google Scholar]

Gupta 1991 {published data only}

• Gupta R, Foster ME, Miller E. Calcium alginate in the management of acute surgical wounds and abscesses. Journal of Tissue Viability 1991;1(4):115‐6. [Google Scholar]

Heal 2009 {published data only}

• Heal CF, Buettner PG, Cruickshank R, Graham D, Browning S, Pendergast J, et al. Does single application of topical chloramphenicol to high risk sutured wounds reduce incidence of wound infection after minor surgery? Prospective randomised placebo controlled double blind trial. BMJ 2009;338:a2812. [DOI: 10.1136/bmj.a2812] [PMC free article] [PubMed] [CrossRef] [Google Scholar]

Hermans 2000 {published data only}

• Hermans M. A prospective clinical trial of wound dressings to investigate the rate of infection under occlusion. First World Wound Healing Congress, 2000 September 10‐13; Melbourne, Australia. 2000:92.

Hirose 2002 {published data only}

• Hirose T, Takahashi S, Shimizu T, Nishiyama N, Furuya R, Takeyama K, et al. Clinical and bacteriological outcomes of post‐operative surgical sites with and without antisepsis in the field of urology. Dermatology 2002;204(Suppl 1):122. [Google Scholar]

Hutchinson 1997 {published data only}

• Hutchinson J. Prospective study of clinical infections in wounds dressed with hydrocolloid versus conventional dressings. Proceedings of the sixth European Conference on Advances in Wound Management, 1996 October 1‐4; Amsterdam, the Netherlands. Amsterdam, 1997:263.

Igarza 1997 {unpublished data only}

• Igarza JL, Conejo JS. A clinical and microbiological evaluation of dressings in dermatological surgery: adhesive strips compared with a thin hydrocolloid. Sixth European Conference on Advances in Wound Management, 1995 November 21‐24; Harrogate, UK. 1995.

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;79 (3):361‐9. [PubMed] [Google Scholar]

Juergens 2011 {published data only}

• Juergens S, Maune C, Kezze F, Mohr T, Scheuer K, Mallman P. A randomized, controlled study comparing the cosmetic outcome of a new wound closure device with prolene suture closing caesarean wounds. Internation Wound Journal 2011;8:329‐35. [PMC free article] [PubMed] [Google Scholar]

Kadar 2015 {published data only}

• Kadar A, Eisenberg G, Yahav E, Drexler M, Salai M, Steinberg EL. Surgical site infection in elderly patients with hip fractures, silver‐coated versus regular dressings: a randomised prospective trial. Journal of Wound Care 2015;24:441‐2,444‐5. [PubMed] [Google Scholar]

Kiefer 2016 {published data only}

• Kiefer DG, Muscat JC, Santorelli J, Chavez MR, Ananth CV, Smulian JC, et al. Effectiveness and short‐term safety of modified sodium hyaluronic acid‐carboxymethylcellulose at cesarean delivery: a randomized trial. American Journal of Obstetrics and Gynecology 2016;214:e1‐373. [PMC free article] [PubMed] [Google Scholar]

Lambiris 1979 {published data only}

• Lambiris E, Friedebold G, Zilch H. Local treatment of surgical infections using PMMA‐spheres and chains ‐ results from Berlin. Aktuelle Probleme in Chirurgie und Orthopadie 1979;12:161‐9. [PubMed] [Google Scholar]

Mandy 1985 {published data only}

• Mandy SH. Evaluation of a new povidine‐iodine impregnated polyethylene oxide gel occlusive dressing. Journal of the American Academy of Dermatology 1985;13(4):655‐9. [PubMed] [Google Scholar]

Marinovic 2010 {published data only}

• Marinović M, Cicvarić T, Juretić I, Grzalja N, Medved I, Ahel J. Application of wound closure Molndal technique after laparoscopic cholecystectomy‐initial comparative study. Collegium Antropologicum  2010;34(Suppl 2):243‐5. [PubMed] [Google Scholar]

Martin‐Garcia 2005 {published data only}

• Martin‐Garcia RF, Janer AL, Rullan FV. Octyl‐2‐cyanoacrylate liquid bandage as a wound dressing in facial excisional surgery: results of an uncontrolled pilot study. Dermatologic Surgery 2005;31:670‐3. [PubMed] [Google Scholar]

Maw 1997 {published data only}

• Maw I, Quinn J, Wells G, Ducic Y, Odell P, Lamothe A, et al. A prospective comparison of octylcyanoacrylate tissue adhesive and suture for the closure of head and neck incisions. The Journal of Otolaryngology 1997;26:26‐30. [PubMed] [Google Scholar]

McVeigh 2011 {published data only}

• McVeigh T, Kovacic D, Tawfick W, Sultan S. Assessing the impact of techniques of wound closure on vascular surgical site infection rates. Irish Journal of Medical Science: Sylvester O'Halloran Meeting. 2011:S114.

Merei 2004 {published data only}

• Merei JM. Pediatric clean surgical wounds: is dressing necessary?. Journal of Pediatric Surgery 2004;39(12):1871‐3. [PubMed] [Google Scholar]

Meylan 2001 {published data only}

• Meylan G, Tschantz P. Surgical wounds with or without dressing. Prospective comparative study [Pansement ou absence de pansement sur les plaies operatoires. Etude prospective comparative]. Annales de Chirurgie 2001;126(5):459‐62. [PubMed] [Google Scholar]

Milne 1999 {published data only}

• Milne CT, Pierpont Barrere CC, McLaughlin T, Moore A. Surgical hip dressings: a comparison of taping methods. Orthopedic Nursing 1999;18(3):37‐42. [PubMed] [Google Scholar]

Moore 1997 {unpublished data only}

• Moore P, Foster L. The use of a hydrofibre dressings in surgical wounds. European Wound Management Association Conference, 1997 April 27‐29; Milan, Italy. 1997:42‐4.

Morales 2006 {published data only}

• Morales Moreira E, Jesus Hernandez M, Granados Hernandez D, Sardinas Lopez G. Use of tisuacryl as tissue adhesive in the healing of cutaneous facial wounds and those of the buccal mucosa [Empleo del Tisuacryl como adhesivo tisular en el cierre de heridas faciales cutáneas y de la mucosa bucal]. Mediciego 2006;12:Available from bvs.sld.cu/revistas/mciego/vol12_supl1_06/articulos/a5_v12_supl106.html. [Google Scholar]

Müller 1993 {unpublished data only}

• Müller K, Matzen E, Gottrup F. Treatment of incisional wound defects following laparotomy, in relation to treatment effect, time consumption and economy. A methodological description. Third European Conference on Advances in Wound Management, 1993 October 19‐22; Harrogate, UK. 1993.

Nearuy 2000 {unpublished data only}

• Nearuy PC, Watson G, Andriessen A. A randomised comparative evaluation of a hydrogel vs paraffin gauze in the management of surgical wounds. First World Wound Healing Congress, 2000 September 10‐13; Melbourne, Australia. 2000.

Palao i Domenech 2008 {published data only}

• Palao i Domenech R, Romanelli M, Tsiftsis DD, Slonkova V, Jortikka A, Johannesen N, et al. Effect of an ibuprofen‐releasing foam dressing on wound pain: a real‐life RCT. Journal of Wound Care 2008;17(8):342,344‐8. [PubMed] [Google Scholar]

Palao i Domenech 2009 {published data only}

• Palao i Domenech R, Prantl L, Larsen AM, Jortikka A. Effects of a foam dressing with ibuprofen on wound pain in acute wounds. European Wound Manangement Association Journal 2009;9(2):102, Abstract P6. [Google Scholar]

Parvizi 2013 {published data only}

• Parvizi D, Friedl H, Schintler MV, Rappl T, Laback C, Wiedner M, et al. Use of 2‐octyl cyanoacrylate together with a self‐adhering mesh (DermabondTM PrineoTM) for skin closure following abdominoplasty: an open, prospective, controlled, randomized, clinical study. Aesthetic Plastic Surgery 2013;37:529‐37. [PubMed] [Google Scholar]

Pastorfide 1989 {published data only}

• Pastorfide GB, Gorgonio NM, Ganzon AR, Alberto RM. Zinc chloride spray‐magnesium hydroxide ointment dual topical regimen in the treatment of obstetric and gynecologic incisional wounds. Clinical Therapeutics 1989;11(2):258‐63. [PubMed] [Google Scholar]

Piromchai 2008 {published data only}

• Piromchai P, Vatanasapt P, Reechaipichitkul W, Phuttharak W, Thanaviratananich S. Is the routine pressure dressing after thyroidectomy necessary? A prospective randomized controlled study. BMC Ear, Nose and Throat Disorders 2008;8:1. [PMC free article] [PubMed] [Google Scholar]

Pizarro Sule 2001 {published data only}

• Pizarro Sule C, Silva Orrego V, Ordenes VM, Bozinovic AF, Cabezas MJ. Management of surgical wounds with occlusive dressings [Manejo de herida operatoria con aposito oclusivo]. Revista Chilena de Cirugía 2001;53:386‐9. [Google Scholar]

Ponnighaus 1999 {published data only}

• Ponnighaus JM, Kowalzick L. Polyurethane or calcium alginate dressings for temporary defects in tumour surgery?. Aktuelle Dermatologie 1999;25(5):133‐5. [Google Scholar]

Ravenscroft 2006 {published data only}

• Ravenscroft MJ, Harker J, Buch KA. A prospective, randomised, controlled trial comparing wound dressings used in hip and knee surgery: Aquacel and Tegaderm versus Cutiplast. Annals of the Royal Collage of Surgeons of England 2006;88(1):18‐22. [PMC free article] [PubMed] [Google Scholar]

Reinicke 1990 {published data only}

• Reinicke G, Nowak W, Adler KP. Does the elastic wound‐dressing Ankerplast spray influence the healing process of wounds? [Beeinflusst der elastische Wundschnellverband Ankerplast‐Spray die Wundheilung?]. Experimentelle Chirurgie 1990;115:111‐6. [PubMed] [Google Scholar]

Ridley 2016 {published data only}

• Ridley N. An audit and trial aiming to reduce the rate of surgical site infections for women having a caesarean section. British Journal of Midwifery 2016;24:170‐1. [Google Scholar]

Robson 2012 {published data only}

• Robson V, Yorke J, Sen RA, Lowe D, Rogers SN. Randomised controlled feasibility trial on the use of medical grade honey following microvascular free tissue transfer to reduce the incidence of wound infection. British Journal of Oral and Maxillofacial Surgery 2012;50:321‐7. [PubMed] [Google Scholar]

Romero 2011 {published data only}

• Romero P, Frongia G, Wingerter S, Holland‐Cunz S. Prospective, randomized, controlled trial comparing a tissue adhesive (Dermabond) with adhesive strips (Steri‐Strips) for the closure of laparoscopic trocar wounds in children. European Journal of Pediatric Surgery 2011;21(3):159‐62. [PubMed] [Google Scholar]

Rosenfeldt 2003 {published data only}

• Rosenfeldt FL, Negri J, Holdaway D, Davis BB, Mack J, Grigg MJ, et al. Occlusive wrap dressing reduces infection rate in saphenous vein harvest site. Annals of Thoracic Surgery 2003;75(1):101‐5. [PubMed] [Google Scholar]

Rushbrook 2014 {published data only}

• Rushbrook JL, White G, Kidger L, Marsh P, Taggart TF. The antibacterial effect of 2‐octyl cyanoacrylate (Dermabond) skin adhesive. Journal of Infection Prevention 2014;15:236‐9. [PMC free article] [PubMed] [Google Scholar]

Schwartz 2014 {published data only}

• Schwartz J, Goss S, Facchin F, Manizate F, Gendics C, Braitman E, et al. A prospective two‐armed trial assessing the efficacy and performance of a silver dressing used postoperatively on high‐risk, clean surgical wounds. Ostomy Wound Management 2014;60:30‐40. [PubMed] [Google Scholar]

Segers 2007 {published data only}

• Segers P, Jong AP, Spanjaard L, Ubbink DT, Mol BA. Randomized clinical trial comparing two options for postoperative incisional care to prevent post‐sternotomy surgical site infections. Wound Repair and Regeneration 2007;15(2):192–6. [PubMed] [Google Scholar]

Shamiyeh 2001 {published data only}

• Shamiyeh A, Schrenk P, Stelzer T, Wayand WU. Prospective randomised blind controlled trial comparing sutures, tape, and octylcyanoacrylate tissue adhesive for skin closure after phlebectomy. Dermatologic Surgery 2001;27:877‐80. [PubMed] [Google Scholar]

Sheppard 2014 {published data only}

• Sheppard C, Kent WD, Fedak P. Negative pressure dressing to decrease the incidence of leg wound complications after CABG: nursing perspectives for patient care. Canadian Journal of Cardiology 2014;30(10):S354. [Google Scholar]

Shima 1998 {published data only}

• Shima Y. Clinical efficacy of thin hydrocolloid dressing (KYD) for healing of surgical wound. Rinsho to Kenkyu (The Japanese Journal of Clinical and Experimental Medicine) 1998;75:669‐79. [Google Scholar]

Signorini 2007 {published data only}

• Signorini M, Clementoni MT. Clinical evaluation of a new self‐drying silicone gel in the treatment of scars: a preliminary report. Aesthetic Plastic Surgery 2007;31(2):183‐7. [PubMed] [Google Scholar]

Singer 2002 {published data only}

• Singer AJ, Quinn JV, Hollander JE. Comparison of octylcyanoacrylate and standard wound closure methods for lacerations and Incisions: a multi‐center trial. Academic Emergency Medicine 2002;131:270‐6. [Google Scholar]

Sinha 2001 {published data only}

• Sinha S, Naik M, Wright V, Timmons J, Campbell AC. A single blind, prospective, randomised trial comparing n‐butyl 2‐cyanoacrylate tissue adhesive (Indermil) and sutures for skin closure in hand surgery. Journal of Hand Surgery 2001;26B:264‐5. [PubMed] [Google Scholar]

Slawson 2002 {published data only}

• Slawson D. How does laceration and incision repair with the tissue adhesive octylcyanoacrylate (Dermabond) compare with standard wound closure methods?. Surgery 2002;5:2. [Google Scholar]

Sondergaard 1982 {published data only}

• Sondergaard JO, Galatius H. Debrisan compared with chloramine packs in the treatment of postoperative wounds. Ugeskrift for Laeger 1982;144(21):1523‐5. [PubMed] [Google Scholar]

Stanirowski 2016a {published data only}

• Stanirowski PJ, Kociszewska A, Cendrowski K, Sawicki W. Dialkylcarbamoyl chloride‐impregnated dressing for the prevention of surgical site infection in women undergoing cesarean section: a pilot study. Archives of Medical Science 2016;12:1‐7. [PMC free article] [PubMed] [Google Scholar]

Stanirowski 2016b {published data only}

• Stanirowski PJ, Bizon M, Cendrowski K, Sawicki W. Randomized controlled trial evaluating dialkylcarbamoyl chloride impregnated dressings for the prevention of surgical site infections in adult women undergoing cesarean section. Surgical Infections 2016;7:427‐35. [PMC free article] [PubMed] [Google Scholar]

Staveski 2013 {published data only}

• Staveski S, Abrajano C, Casazza M, Dong E, Petty A, Felix K, et al. Silver dressings for sternotomy incision care in pediatric cardiac patients to decrease surgical site infections. Pediatric Critical Care Medicine 2013;14(Suppl 1):S97. [Google Scholar]

Staveski 2016 {published data only}

• Staveski S, Abrajano C, Casazza M, Bair E, Quan H, Dong E, et al. Silver‐Impregnated dressings for sternotomy incisions to prevent surgical site infections in children. American Journal of Critical Care 2016;25:402‐8. [PubMed] [Google Scholar]

Terrill 2000 {published data only}

• Terrill PJ, Varughese G. A comparison of three primary non‐adherent dressings applied to hand surgery wounds. Journal of Wound Care 2000;9(8):359‐63. [PubMed] [Google Scholar]

Teshima 2009 {published data only}

• Teshima H, Kawano H, Kashikie H, Nakamura K, Imada T, Oda T, et al. A new hydrocolloid dressing prevents surgical site infection of median sternotomy wounds. Surgery Today 2009;39(1):848‐54. [PubMed] [Google Scholar]

Tofuku 2012 {published data only}

• Tofuku K, Koga H, Yanase M, Komiya S. The use of antibiotic‐impregnated fibrin sealant for the prevention of surgical site infection associated with spinal instrumentation. European Spine Journal 2012;21:2027‐33. [PMC free article] [PubMed] [Google Scholar]

Torra i Bou 2013 {published data only}

• Torra i Bou JE, Abejon Arroyo A, Garcia Veira M, Cabero Garcia B, Gonzalez Carbjose MJ, Garcis Caridad L, et al. Clinical comparison of a film surgical dressing versus gauze tape dressing in the management of post‐operative surgical wounds in orthopedic surgery patients. European Wound Management Association Journal 2013;13(Suppl 167):Abstract 277. [Google Scholar]

Ubbink 2008 {published data only}

• Ubbink DT, Vermeulen H, Goossens A, Kelner RB, Schreuder SM, Lubbers MJ. Occlusive vs gauze dressings for local wound care in surgical patients: a randomized clinical trial. Archives of Surgery 2008;143(10):950‐5. [PubMed] [Google Scholar]
• Ubbink DT, Vermeulen H, Goossens A . Modern versus gauze dressings to treat open wounds in surgical patients: a randomised clinical trial. Australian Wound Management Association Seventh National Conference: Dreams, Diversity, Disasters, 2008 May 7‐10; Darwin, Australia. 2008.

Valente 2008 {published data only}

• Valente M, Patricio A, Sousa A, Brilhante F. The Molndal technique: a comparative assessment. European Wound Management Association Journal  2008;2(Suppl 2):Abstract P194. [Google Scholar]

Widgerow 2009 {published data only}

• Widgerow AD, Chait LA, Stals PJ, Stals R, Candy G. Multimodality scar management program. Aesthetic Plastic Surgery 2009;33(4):533‐43. [PubMed] [Google Scholar]

Wipke‐Tevis 1993 {unpublished data only}

• Wipke‐Tevis D, Stotts NA. Dressings, cosmetic result, pain, distress and wound healing of surgical incisions. First Joint Meeting of the Wound Healing Society and the European Tissue Repair Society, 1993 August 22‐25; Amsterdam, the Netherlands. 1993.

Wipke‐Tevis 1998 {published data only}

• Wipke‐Tevis DD, Stotts NA. Effect of dressings on saphenous vein harvest incision pain, distress and cosmetic result. Progress in Cardiovascular Nursing 1998;13(3):3‐13. [PubMed] [Google Scholar]

Yamanaka 2012 {published data only}

• Yamanaka N, Tanaka M. Examination of film material suitable for wound management after abdominal surgery. Fourth Congress of the World Union of Wound Healing Societies, 2012 September 2‐6; Yokohama, Japan. 2012.

Yang 2013 {published data only}

• Yang X, Zhou H‐F, Zhang S‐M, Wang Y‐Z, Ye N, Wang Y, et al. Hydrofiber dressing with silver in wound healing after surgery for anal fistula. Chinese Journal of Tissue Engineering Research 2013;16:8835‐41. [Google Scholar]

References to studies awaiting assessment

Goharshenasan 2016 {published data only}

• Goharshenasan P, Amini S, Atria A, Abtahi H, Khorasani G. Topical application of honey on surgical wounds: a randomized clinical trial. Forschende Komplementarmedizin 2016;23:12‐5. [PubMed] [Google Scholar]

Siddiqui 2016 {published data only}

• Siddiqui M, Bidaye A, Baird E, Abu‐Rajab R, Stark A, Jones B, et al. Wound dressing following primary total hip arthroplasty: a prospective randomised controlled trial. Journal of Wound Care 2016;40:42‐5. [PubMed] [Google Scholar]
• Siddiqui M, Bidaye A, Baird E, Jones B, Stark A, Abu‐Rajab R, et al. Wound closure following primary total hip arthroplasty. Tenth Congress of the European Hip Society, 2012 September 20‐22; Milan, Italy. Milan, Italy: Wichtig Publishing Srl, 2012:425.

Springer 2015 {published data only}

• Springer BD, Beaver WB, Griffin WL. The role of surgical dressings in total knee arthroplasty: a randomized clinical trial. Current Orthopaedic Practice 2013;24(4):452‐3. [Google Scholar]
• Springer BD, Beaver WB, Griffin WL, Mason JB, Odum SM. Role of surgical dressings in total joint arthroplasty: a randomized controlled trial. American Journal of Orthopedics 2015;44:415‐20. [PubMed] [Google Scholar]

References to ongoing studies

ISRCTN06792113 {published data only}

• ISRCTN06792113. The Bluebelle Study: complex, simple and absent wound dressings in elective surgery: Phase A. www.isrctn.com/ISRCTN06792113 (first received 18 March 2014).

{"type":"clinical-trial","attrs":{"text":"NCT02619773","term_id":"NCT02619773"}}NCT02619773 {published data only}

• NCT02619773. Effect of mupirocin dressings versus island dressings on surgical site infections in elective colorectal surgery. clinicaltrials.gov/ct2/show/NCT02619773 (first received 30 November 2015).

{"type":"clinical-trial","attrs":{"text":"NCT02771015","term_id":"NCT02771015"}}NCT02771015 {published data only}

• NCT02771015. Performance of flexible self‐adherent absorbent dressing coated with a soft silicone layer after hip‐, knee‐arthroplasty, primary spine surgery in comparison to a standard wound dressing (wound dressing). clinicaltrials.gov/ct2/show/NCT02771015 (first received 8 September 2015).

{"type":"clinical-trial","attrs":{"text":"NCT02904200","term_id":"NCT02904200"}}NCT02904200 {published data only}

• NCT02904200. Clinical investigation of two different wound dressings. clinicaltrials.gov/show/NCT02904200 (first received 13 September 2016).

Additional references

Allegranzi 2016

• Allegranzi B, Zayed B, Bischoff P, Kubilay NZ, Jonge S, Vries F, et al. New WHO recommendations on intraoperative and postoperative measures for surgical site infection prevention: an evidence‐based global perspective. Lancet Infectious Diseases 2016;S1473‐3099:30402‐9 [Epub ahead of print]. [PubMed] [Google Scholar]

Astagneau 2009

• Astagneau P, L'Hériteau F, Daniel F, Parneix P, Venier AG, Malavaud S, et al. Reducing surgical site infection incidence through a network: results from the French ISO‐RAISIN surveillance system. Journal of Hospital Infection 2009;72(2):127‐34. [PubMed] [Google Scholar]

BNF 2016

• British Medical Association and Royal Pharmaceutical Society of Great Britain. British National Formulary (BNF): Appendix 5: wound management products and elasticated garments. www.evidence.nhs.uk/formulary/bnf/current/a5‐wound‐management‐products‐and‐elasticated‐garments (accessed 4 November 2016).

Bruce 2001

• Bruce J, Russell EM, Mollison J, Krukowski ZH. The measurement and monitoring of surgical adverse events. Health Technology Assessment Monograph 2001;5(22):1‐194. [PubMed] [Google Scholar]

Button 2010

• Button KS, Ioannidis JP, Mokrysz C, Nosek BA, Flint J, Robinson ES, et al. Power failure: why small sample size undermines the reliability of neuroscience. Nature Reviews Neuroscience 2010;14:365‐76. [PubMed] [Google Scholar]

de Lissovoy 2009

• Lissovoy G, Fraeman K, Hutchins V, Murphy D, Song D, Vaughn BB. Surgical site infection: incidence and impact on hospital utilization and treatment costs. American Journal of Infection Control 2009;37(5):387‐97. [PubMed] [Google Scholar]

Deeks 2002

• Deeks JJ. Issues in the selection of a summary statistic for meta‐analysis of clinical trials with binary outcomes. Statistics in Medicine 2002;21:1575‐600. [PubMed] [Google Scholar]

Deeks 2011

• Deeks JJ, Higgins JP, Altman DG, on behalf of the Cochrane Statistical Methods Group. Chapter 9: Analysing data and undertaking meta‐analyses. In: Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

Gibbons 2011

• Gibbons C, Bruce J, Carpenter J, Wilson AP, Wilson J, Pearson A, et al. Identification of risk factors by systematic review and development of risk‐adjusted models for surgical site infection. Health Technology Assessment 2011;15(30):1‐156. [PubMed] [Google Scholar]

Goldman 1992

• Goldman MP, Fronek A. Consensus paper on venous leg ulcer. Journal of Dermatology Surgery and Oncology 1992;18:592‐602. [PubMed] [Google Scholar]

GRADE 2013

• Schünemann H, Brożek J, Guyatt G, Oxman A, editor(s), GRADE working group. GRADE Handbook. gdt.guidelinedevelopment.org/central_prod/_design/client/handbook/handbook.html (accessed 5 February 2016).

Health Protection Agency 2002

• Health Protection Agency. Surveillance of surgical site infection in English hospitals 1997‐2002. A national surveillance and quality improvement programme. London (UK): Health Protection Agency, 2002. [Google Scholar]

Higgins 2003

Higgins 2011

• Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

Horan 2008

• Horan TC, Andrus M, Dudeck MA. DC/NHSN surveillance definition of healthcare‐associated infection and criteria for specific types of infections in the acute care setting. American Journal of Infection Control 2008;36(5):309‐32. [PubMed] [Google Scholar]

Hróbjartsson 2012

• Hróbjartsson A, Thomsen AS, Emanuelsson F, Tendal B, Hilden J, Boutron I, et al. Observer bias in randomised clinical trials with binary outcomes: systematic review of trials with both blinded and non‐blinded outcome assessors. BMJ 2012;344:e1119. [PubMed] [Google Scholar]

Lefebvre 2011

• Lefebvre C, Manheimer E, Glanville J. Chapter 6: Searching for studies. In: Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

McLaws 2000

• McLaws ML, Murphy C, Whitby M. Standardising surveillance of nosocomial infections: the HISS program. Hospital Infection Standardised Surveillance. Journal of Quality in Clinical Practice 2000;20(1):6–11. [PubMed] [Google Scholar]

NICE 2008

• National Institute of Health and Care Excellence (NICE). Surgical site infections: prevention and treatment. Clinical guideline [CG74]. October 2008. www.nice.org.uk/guidance/cg74 (accessed 4 November 2016).

Plowman 2001

• Plowman R, Graves N, Griffin MA, Roberts JA, Swan AV, Cookson B, et al. The rate and cost of hospital‐acquired infections occurring in patients admitted to selected specialties of a district general hospital in England and the national burden imposed. Journal of Hospital Infection 2001;47(3):198‐209. [PubMed] [Google Scholar]

RevMan 2014 [Computer program]

• The Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager (RevMan). Version 5.3. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014.

Schulz 2010

• Schulz KF, Altman DG, Moher D, CONSORT Group. CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. PLOS Med 2010;7:e1000251. [PMC free article] [PubMed] [Google Scholar]

Schünemann 2011a

• Schünemann HJ, Oxman AD, Higgins JP, Deeks JJ, Glasziou P, Guyatt GH. Chapter 12: Interpreting results and drawing conclusions. In: Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

Schünemann 2011b

• Schünemann HJ, Oxman AD, Higgins JP, Vist GE, Glasziou P, Guyatt GH. Chapter 11: Presenting results and 'Summary of findings' tables. In: Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

SIGN 2015

• Scottish Intercollegiate Guidelines Network (SIGN). Search filters. www.sign.ac.uk/methodology/filters.html#random (accessed 4 November 2016).

Smyth 2008

• Smyth ET, McIlvenny G, Enstone JE, Emmerson AM, Humphreys H, Fitzpatrick F, et al. Four country healthcare associated infection prevalence survey 2006: overview of the results. Journal of Hospital Infection 2008;69(3):230‐48. [PubMed] [Google Scholar]

Sterne 2011

• Sterne JA, Egger M, Moher D. Chapter 10: Addressing reporting biases. In: Higgins JP, Green S, editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

References to other published versions of this review

Walter 2012

• Walter CJ, Dumville JC, Sharp CA, Page T. Systematic review and meta‐analysis of wound dressings in the prevention of surgical‐site infections in surgical wounds healing by primary intention. British Journal of Surgery 2012;9(9):1185‐1194. [PubMed] [Google Scholar]

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