Hoewel er door chirurgen veel aandacht wordt besteed aan het voorkomen van postoperatieve wondinfecties (POWI’s), zijn wondinfecties van de plaats van incisie een frequent postoperatief ongewenst voorval dat de veiligheid van de patiënt in gevaar brengt en de kosten van de gezondheidszorg verhoogt. Een nauwgezette aseptische operatietechniek en de toediening van adequate antibioticaprofylaxe voorkomen postoperatieve wondinfectie door contaminatie te verminderen en micro-organismen die de operatieplaats binnendringen te elimineren.

Conventionele chirurgische afdekdoeken of disposable afdekmateriaal met kleefrand worden gewoonlijk door chirurgen gebruikt om het aseptische operatiegebied te beperken en de wondranden af te dekken. Deze mechanische barrière kan echter losraken of mogelijk gecontamineerd raken.

Er bestaan verschillende chirurgische wondbeschermers (WP). Deze nieuwe chirurgische hulpmiddelen bestaan uit een niet-klevende plastic sheet die is bevestigd aan een enkele of dubbele flexibele rubberen ring die de plastic sheet stevig om de wondranden heen vastzet, waarbij de laparotomiewond verder wordt opengesperd. Bij een enkele flexibele rubberen ring bevindt deze ring zich onder de wondrand tegen het peritoneale oppervlak. Bij de dubbele flexibele rubber ring is eerste ring onder de wondrand tegen het peritoneum aan en de tweede ring op de huid rondom de laparotomiewond; de plastic sheet bevindt zich daartussen en bedekt de incisierand rondom. Deze chirurgische hulpmiddelen zijn op de markt beschikbaar, maar het is belangrijk om de effectiviteit en kosteneffectiviteit te onderzoeken.

Deze module betreft een adaptatie van de module ‘Wound protector devices’ van de WHO-richtlijn ‘Global guidelines for the prevention of surgical site infection’ (2018). Voor een toelichting op de procedure van adapteren wordt verwezen naar de Bijlage Adapteren.

^{Disclaimer: Dit is een adaptatie van een origineel werk ‘Global guidelines for the prevention of surgical site infection, second edition. Geneva: World Health Organization; 2018. License: CC BY-NC-SA 3.0 IGO.’ (https://www.who.int/publications/i/item/9789241550475). Deze adaptatie is niet uitgevoerd door de WHO. De WHO is niet verantwoordelijk voor de inhoud of nauwkeurigheid van deze adaptatie. De originele uitgave is de bindende en authentieke uitgave.}

1. Surgical site infections (all studies; single-ring and double-ring)¹

Surgical site infections (single-ring)

Surgical site infections (double-ring)

2. Surgical site infections (degree of wound contamination)¹

Surgical site infections (clean-contaminated surgery)

Surgical site infections (contaminated surgery)

Surgical site infections (dirty surgery)

3. SSI-attributable mortality¹

^{Disclaimer: This is an adaptation of an original work “Global guidelines for the prevention of surgical site infection, second edition. Geneva: World Health Organization; 2018. License: CC BY-NC-SA 3.0 IGO.” (https://www.who.int/publications/i/item/9789241550475). This adaptation was not created by WHO. WHO is not responsible for the content or accuracy of this adaptation. The original edition shall be the binding and authentic edition.}

^{1 The WHO-guideline did not provide GRADE-conclusions for the effect of wound protector devices compared to conventional wound protection in patients undergoing clean-contaminated, contaminated, and dirty surgery. The GRADE-conclusions for clean-contaminated, contaminated, and dirty surgery for this module were prepared in accordance with the standard procedures of the Knowledge Institute of the Federation of Medical Specialists.}

Description of studies

Eleven studies, including ten randomized controlled trials (Baier, 2012; Cheng, 2012; Horiuchi, 2007; Lee, 2009; Mihaljevic, 2014; Pinkney, 2013; Redmond, 1994; Reid, 2010; Sookhai, 1999; Theodoridis, 2011) and one prospective controlled trial (Brunet, 1994), comparing the use of a WP device vs. conventional wound protection were identified with an SSI outcome. Patients were adults undergoing abdominal surgical procedures with laparotomy.

Six studies (Baier, 2012), Mihaljevic, 2014; Pinkney, 2013; Remond, 1994), Sookhai, 1999; Brunet, 1994) used a single-ring WP device as the intervention. Among these, four trials (Mihaljevic, 2014; Redmond, 1994; Sookhai, 1999; Brunet, 1994) demonstrated that the use of a single-ring WP led to a significant reduction of the SSI rate when compared with standard wound protection. However, two trials showed no difference of risk (Baier, 2012; Pinkney, 2013). A meta-analysis of this subgroup (Comparisons) showed the benefit of a single-ring WP in reducing the SSI rate when compared with standard wound protection (OR: 0.51; 95% CI; 0.34–0.76) (RR: 0.58 95% CI 0.41 to 0.82).

Five (Cheng, 2012; Horiuchi, 2007; Lee, 2009; Reid, 2010; Theodoridis, 2011) of the eleven studies used a double-ring WP device as the intervention. In two trials (Lee, 2009; Reid, 2010), there was a significant reduction of the SSI rate when using a double-ring WP. Three trials (Cheng, 2012; Horiuchi, 2007; Theodoridis, 2011) showed no difference in risk. A meta-analysis of this subgroup (Comparisons) showed the benefit of a double-ring WP in reducing the rate of SSI (OR: 0.25; 95% CI: 0.13– 0.50) (RR: 0.29 95% CI 0.15 to 0.55).

Results

1. Surgical site infections

The overall meta-analysis (Comparisons) including all eleven studies showed the benefit of using a WP device when compared with standard wound protection in reducing the rate of SSI (OR: 0.42; 95% CI: 0.28 to 0.62) (RR: 49 95% CI: 0.34 to 0.69). In meta-regression analysis, there was no strong evidence for a difference in the effect between a single- and double-ring WP (P=0.107). A sensitivity analysis comparing the RCTs, and the prospective controlled trial (Brunet, 1994) indicated that there was no difference in the results, irrespective of whether the quasi-randomized trial was included or not.

The quality of the evidence for this comparison was very low due to risk of bias, inconsistency, and publication bias (Risk of bias assessment of the included studies). Most studies had an unclear to high risk in random sequence generation and unclear allocation concealment. There was considerable asymmetry observed in the funnel plot, compatible with the preferential publication of small studies demonstrating a benefit (Comparisons).

A subgroup analysis discriminating between different degrees of wound contamination in abdominal surgery (clean-contaminated, contaminated and dirty) showed that the use of a WP device is beneficial in reducing the SSI rate when compared to standard wound protection in clean-contaminated (OR: 0.63; 95% CI: 0.4–0.99) (RR: 0.68 95% CI 0.46 to 1.01) and contaminated (OR: 0.31; 95% CI: 0.15–0.64) (RR: 0.45 95% CI: 0.30 to 0.68) procedures, but not in dirty (OR: 0.22; 95% CI: 0.04–1.21) (RR: 0.60 95% CI 0.30 to 1.28) surgery (Comparisons). However, in meta-regression analysis, there was no evidence that the effect differed between clean-contaminated (P=0.244) or contaminated (P=0.305) or dirty (P=0.675) surgery and other surgery.

The body of retrieved evidence focused on adult patients and no study was available in the paediatric population. The literature search did not identify any studies that reported SSI-attributable mortality.

1. Surgical site infections (all studies; single-ring and double-ring) 

Comparison 1: Wound protector device (single- and double-ring) vs. conventional wound protection in abdominal surgery

Forest plot showing the comparison between wound protector devices to conventional wound protection for surgical site infections. Pooled risk-ratio, random effects model. Z: p-value of overall effect; df: degrees of freedom; I2; statistical heterogeneity; CI: confidence interval.

2. Surgical site infections (degree of wound contamination)

Comparison 2: Wound protector vs. no wound protector. Subgroup analysis of degree of wound contamination (clean-contaminated, contaminated, and dirty)

Forest plot showing the comparison between wound protector devices to conventional wound protection for surgical site infections in clean-contaminated surgery, contaminated surgery, and dirty surgery. Pooled odds-ratio, random effects model. Z: p-value of overall effect; df: degrees of freedom; I2; statistical heterogeneity; CI: confidence interval.

Forest plot showing the comparison between wound protector devices to conventional wound protection for surgical site infections in clean-contaminated surgery, contaminated surgery, and dirty surgery. Pooled risk-ratio, random effects model. Z: p-value of overall effect; df: degrees of freedom; I2; statistical heterogeneity; CI: confidence interval.

3. SSI-attributable mortality

The literature search did not identify any studies that reported SSI-attributable mortality.

Level of evidence of the literature¹

1. Surgical site infections (all studies; single-ring and double-ring)

The level of evidence regarding the outcome surgical site infections (overall analysis) was derived from randomized controlled trials and therefore started high. The level of evidence was downgraded by two levels because of risk of selection bias (risk of bias, -1) and risk of publication bias (other bias, -1). The level of evidence was considered as low (GRADE Table).

Surgical site infections (single-ring)

The level of evidence regarding the outcome surgical site infections (single-ring) was derived from randomized controlled trials and therefore started high. The level of evidence was downgraded by two levels because of risk of selection bias (risk of bias, -1) and because of high heterogeneity (inconsistency, -1) The level of evidence was considered as low (GRADE Table).

Surgical site infections (double-ring)

The level of evidence regarding the outcome surgical site infections (double-ring) was derived from randomized controlled trials and therefore started high. The level of evidence was downgraded by two levels because of risk of selection bias (risk of bias, -1) and because the optimal information size was not met (imprecision, -1). The level of evidence was considered as low (GRADE Table).

2. Surgical site infections (degree of wound contamination)

Surgical site infections (clean-contaminated surgery)

The level of evidence regarding the outcome surgical site infections (clean-contaminated surgery) was derived from randomized controlled trials and therefore started high. The level of evidence was downgraded by two levels because of risk of selection bias (risk of bias, -1) and the wide confidence interval crossing the lower threshold of clinical relevance (imprecision, -1). The level of evidence was considered as low (GRADE Table).

Surgical site infections (contaminated surgery)

The level of evidence regarding the outcome surgical site infections (contaminated surgery) was derived from randomized controlled trials and therefore started high. The level of evidence was downgraded by two levels because of the risk of selection bias (risk of bias, -1) and the small number of events (imprecision, -1). The level of evidence was considered as low (GRADE Table).

Surgical site infections (dirty surgery)

The level of evidence regarding the outcome surgical site infections (clean-contaminated surgery) was derived from randomized controlled trials and therefore started high. The level of evidence was downgraded by two levels because of risk of selection bias (risk of bias, -1) and because of high heterogeneity (inconsistency, -1). The level of evidence was considered as low (GRADE Table).

3. SSI-attributable mortality

Since none of the included studies reported information regarding SSI-attributable mortality, the level of evidence could not be graded.

^{Disclaimer: This is an adaptation of an original work “Global guidelines for the prevention of surgical site infection, second edition. Geneva: World Health Organization; 2018. License: CC BY-NC-SA 3.0 IGO.” (https://www.who.int/publications/i/item/9789241550475). This adaptation was not created by WHO. WHO is not responsible for the content or accuracy of this adaptation. The original edition shall be the binding and authentic edition.}

^{1 The WHO-guideline did not provide GRADE-conclusions for the effect of wound protector devices compared to conventional wound protection in patients undergoing clean-contaminated, contaminated, and dirty surgery. The GRADE-conclusions for clean-contaminated, contaminated, and dirty surgery for this module were prepared in accordance with the standard procedures of the Knowledge Institute of the Federation of Medical Specialists.}

A systematic review of the literature was performed to answer the following question: What are the (un)beneficial effects of wound protector devices on the incidence of surgical site infections (SSI) and SSI-attributable mortality in inpatients and outpatients undergoing surgical operations (any type of procedure)?¹

P:           Inpatients and outpatients of any age undergoing either elective or urgent abdominal surgery

     through conventional open access.

I:            Use of single or double plastic ring wound protector (WP) devices.

C:          Conventional wound protection, mainly through placing wet towels between the wound edge and steel type retractors.

O:          Surgical site infections (SSI), SSI-attributable mortality.

Relevant outcome measures²

The guideline development group considered surgical site infections as a critical outcome for decision making; and SSI-attributable mortality as an important outcome for decision making.

The working group defined a threshold of 10% for continuous outcomes, a relative risk ratio (RR) of <0.95 and >1.05 for SSI-attributable mortality, and a RR of <0.80 and >1.25 for other dichotomous as minimal clinically (patient) important differences.

Search and select (Methods)

The WHO searched the following databases: Medline (PubMed); EMBASE; Cumulative Index to Nursing and Allied Health Literature (CINAHL); Cochrane Central Register of Controlled Trials (CENTRAL); and WHO regional medical databases. The time limit for the review was between 1 January 1990 and 28 November 2014. Language was restricted to English, French and Spanish. A comprehensive list of search terms was used, including Medical Subject Headings (MeSH). The detailed search strategy is available under the "Evidence tabellen" tab.

Two independent reviewers screened the titles and abstracts of retrieved references for potentially relevant studies. The full text of all potentially eligible articles was obtained, and two authors then independently reviewed these for eligibility based on inclusion criteria. Duplicate studies were excluded.

The WHO systematic literature search resulted in 1135 hits. Forty-six studies were initially selected based on title and abstract screening. After reading the full text, thirty-five studies were excluded (Study selection) ten randomized controlled trial and one quasi-randomized controlled trial were included. The two authors extracted data in a predefined evidence table (Evidence table) and critically appraised the retrieved studies. Quality was assessed using the Cochrane Collaboration tool to assess the risk of bias of randomized controlled studies (RCTs) (3) (Appendix 3). Any disagreements were resolved through discussion or after consultation with the senior author, when necessary. Meta-analyses of available comparisons were performed using Review Manager version 5.3 as appropriate (4) (Comparisons). Adjusted odds ratios (OR) with 95% confidence intervals (CI) were extracted and pooled for each comparison with a random effects model. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology (5) (GRADE Pro software) (6) was used to assess the quality of the body of retrieved evidence (Appendix 5). In addition to the WHO meta-analyses, relative risks (RR) and risk differences (RD) with 95% confidence intervals (CI) were extracted and pooled with a random effects model and added to the current literature analysis.

Results³

Eleven studies were included in the analysis of the literature (Summary of literature). Important study characteristics and results are summarized in Evidence table. The assessment of the risk of bias is summarized in Risk of bias assessment of the included studies.

^{Disclaimer: This is an adaptation of an original work “Global guidelines for the prevention of surgical site infection, second edition. Geneva: World Health Organization; 2018. License: CC BY-NC-SA 3.0 IGO.” (https://www.who.int/publications/i/item/9789241550475). This adaptation was not created by WHO. WHO is not responsible for the content or accuracy of this adaptation. The original edition shall be the binding and authentic edition.}

^{1 The working group modified the WHO-search question by including all WHO-defined outcomes.}

^{2 The WHO-guideline did not distinguish between crucial and important outcome measures and did not define thresholds for clinical decision making.}

^{3 The WHO-guideline did not report risk ratios and risk differences.}