To determine whether delayed primary skin closure of contaminated and dirty abdominal surgical incisions is superior to primary skin closure.

A systematic search of OVID SP version of MEDLINE, Pubmed version of MEDLINE, the Cochrane Database of Systematic Reviews, Current Controlled Trials, clinicaltrials.gov, will be performed for published randomised controlled trials comparing primary skin closure (PC) and delayed primary skin closure (DPC). Only studies published after 1990 will be included, and no language restrictions will be applied. The search will be performed independently by two researchers. MeSH terms will be used to search MEDLINE, combining domains of the operation, wound infection and randomisation with the AND function.

A manual search of reference lists in relevant systematic reviews will be undertaken to further identify randomised trials of potential interest. Abstracts and conference proceedings will be excluded because of the high probability of incomplete data. Citations will be collated with EndNote Reference Manager (Version X4, Thomson Reuters) and duplicates removed.

Randomized controlled trials

Surgical site infections

Post-operative complications

Inclusion criteria:

Randomized controlled trials comparing primary closure (PC) versus delayed wound closure (DPC) of the skin layer of contaminated and dirty abdominal surgical incisions will be included. DPC was defined as the planned action to leave the skin edges unopposed (following fascial closure) with a delayed attempt to subsequently oppose the skin edges. Any surgical incision of the abdomen will be eligible.

Exclusion criteria:

The following exclusion criteria will be applied: non-randomised studies; studies published prior to 1990; studies where the fascia was left open; studies considering planned healing by secondary intention (where no assessment for delayed closure was planned).

Randomized controlled trials comparing primary closure (PC) versus delayed wound closure (DPC) of the skin layer of contaminated and dirty abdominal surgical incisions will be included.

The non-exposed group will consist of those undergoing primary skin closure.

Primary outcomes

The primary outcome assessed for meta-analysis will be the rate of surgical site infection.

A definition of surgical site infection specific to this study will be used.

Secondary outcomes

Secondary outcomes recorded will be: rate of healing by secondary intention (which included superficial wound dehiscence for the PC group); rate of fascial dehiscence; length of stay.

Two authors will extract data independently. Discrepancies in outcome extraction will be resolved by re-examination of the relevant study until consensus is achieved.

Data extracted on study design include: randomisation technique, intervention arms, wound contamination as defined by the criteria set by the Centre for Disease Control, adjuncts to delayed closure, concomitant antibiotic therapy, time to first assessment for delayed closure, method of delayed closure, definition of wound infection, method of assessment for wound infection.

Details related to included patients will be: number, age, gender, operation indication, presence of diabetes, malnutrition, steroids, cardiovascular disease, obesity, malignancy, smoking or duration of symptoms >4 hours, mean length of incision.

Risk of bias will be assessed using the Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. The risk of bias tool covers six domains of bias: selection bias, performance bias, detection bias, attrition bias, reporting bias, and other bias. Each domain will be scored as a high, low or uncertain risk of bias. Since blinding is not feasible, this will not not assessed as a source of high bias. To counter this, adequate randomisation is considered vital to minimise the risk of bias introduced by lack of blinding. Studies with poor, uncertain or unclear randomisation will be considered to be at high risk of bias.

Meta-analysis will be conducted according to guidelines from the Preferred Reporting Items for Systematic reviews and Meta-Analysis group (PRISMA). The odds ratio (OR) will be used as the statistical measure for dichotomous outcomes. ORs will be calculated from the original data and meta-analysed using the Mantel–Haenszel method. If an outcome is presented only as an OR, this will be extracted and meta-analysed using the generic inverse variance algorithm.

Pre-specified sensitivity analysis will be performed for the following groups: studies at low risk of bias; wounds for appendicectomy; and wounds classified as ‘dirty’.

Publication in a peer reviewed surgical journal

Aneel Bhangu

C/O Doug Bowley

Royal Centre for Defence Medicine

Birmingham Research Park

Vincent Drive

Birmingham

B15 2SQ

aneelbhangu@doctors.org.uk

Royal Centre for Defence Medicine

Mr Aneel Bhangu, Royal Centre for Defence Medicine
Dr Jonathan Lundy, Royal Centre for Defence Medicine
Mr Douglas Bowley, Royal Centre for Defence Medicine

15 October 2012

30 November 2012

None

None known

English

England

Subject indexing assigned by CRD

Abdominal Wound Closure Techniques; Humans; Surgical Wound Infection;

10 October 2012

10 October 2012