A randomized controlled trial of negative pressure wound therapy to reduce colorectal surgical site infection

Background: The rate of surgical site infection (SSI) in clean-contaminated wounds resulting from elective colorectal procedures ranges from 15 to 30%. Within the region considered in the study, the SSI rate is 20% despite the adoption of preventative measures. Objective: The objective of this study was to determine the effectiveness of prophylactic negative pressure wound therapy (NPWT) in reducing superficial SSIs in clean-contaminated wounds resulting from elective colorectal surgery to below 10%. Design: An unblinded randomized controlled trial was conducted. Settings: The study was conducted at two Canadian tertiary academic hospitals. Patients and Methods: Patients undergoing elective, non-emergent, clean-contaminated colorectal resection by both laparoscopic and open procedures were included. Participants were randomized to either standard surgical dressing (SSD) or NPWT over a closed incision. Main Outcome Measures: Incidence of superficial SSI on postoperative day 30. Results: The study closed early due to lack of accrual. From the planned group of 398 patients, 126 were randomly assigned to SSD (n = 61) or NPWT (n = 61). The analysis included 55 patients from the SSD group and 47 from the NPWT group. The mean age for the groups was 64.9 years (SSD) and 65.1 years (NPWT) with males comprising 52.7% (n = 29) and 44.7% (n = 21) of the populations, respectively. The results showed a clinically important but statistically non-significant difference between the two groups. The overall rate of SSI in the as-treated analysis was 14.7%, while it was slightly lower at 13.5% in the intent-to-treat (ITT) analysis. In both cases, there was a trend toward higher rates of SSI in the SSD, with the ITT analysis showing somewhat larger differences; however, in both the logistic regression models, the trends were non-significant. Conclusion: We present a randomized controlled trial of prophylactic NPWT following elective colorectal resection. The results indicated a clinically important reduction in the superficial SSI rate compared with standard surgical dressing. A more extensive randomized study is needed to clarify the effectiveness of NPWT to reduce wound infections in this patient population. Limitations: Neither patients nor clinicians were blinded to the treatment. The lack of recruitment introduced a type two statistical error, which led to a non-significant difference between the cases and controls. Conflict of Interest: None.