“The routine application of a wound protector should be considered for gastrointestinal and biliary tract surgery, especially because the intervention is relatively safe and the outcome of SSI is associated with significant postoperative morbidity and mortality,” the study team concludes a paper online May 11 in Annals of Surgery.
Wound protectors protect the abdominal wound edges from contamination and trauma during laparotomy. There are two basic types: those with an internal and external ring connected by impervious plastic and those with a single, internal ring connected to a drape that extends outward, over the wound edges and onto the abdomen where they are affixed with adhesive or clips.
Studies on their value in reducing SSI have yielded mixed results, which has fueled “significant uncertainty in the surgical community,” Dr. Chad G. Ball, of the Department of Surgery, University of Calgary and Foothills Medical Center, Calgary, Alberta, Canada, and colleagues say. To their knowledge, this meta-analysis is the first to address this important issue.
They identified and included in the analysis six randomized controlled trials that evaluated the risk of SSI after gastrointestinal and biliary surgeries with and without use of an impervious wound protector. The studies included a total of 1008 patients. They were published between 1984 and 2010 and were conducted in various counties including Sweden, Ireland, Japan, United States and Australia.
The pooled analysis showed that using one of these devices cut the risk of SSI by a significant 45% (RR 0.55; p=0.04).
“Our number needed to treat suggests that only 10 patients would have to be treated intraoperatively with a wound protector to prevent one SSI,” Dr. Ball and colleagues report. “To put this value into context, a meta-analysis evaluating the efficacy of aspirin therapy in the primary prevention of myocardial infarction suggests that 44 patients would have to be treated for 5 years to prevent a single incident case.”
This meta-analysis of “rigorously chosen RCTs was sufficiently powered to detect a 10% absolute risk reduction in SSI,” the investigators point out in their article. They say they only included trials that, “when adequately powered, provide balance on measured and unmeasured confounders.”
The analysis also revealed a nonsignificant trend toward greater protection with a dual ring protector (RR = 0.31; p=0.003) as opposed to a single ring protector (RR = 0.83; p=0.64).
“Although the dual ring structure hypothetically provides closer, more reliable approximation of the device to inner and outer surfaces of the abdominal wall, this observed trend may result from other between-study differences that have evolved concurrently with wound protection technology,” the investigators say.
In comments to Reuters Health, Dr. Ball advised clinicians to “consider employing wound protectors (particularly the double ring format) in any major laparotomy. This seems to be particularly important for procedures that may involve contamination with bowel contents, bile, blood or purulent materials. The primary drawback is cost. However, these devices tend to pay for themselves with very few infections saved.”
None of the author has any connection with the manufacturers of any of the products described in their study.