COMPARATIVE EFFICACY OF PRIMARY CLOSURE VS. DELAYED PRIMARY CLOSURE IN CONTAMINATED ABDOMINAL WOUNDS: A RANDOMIZED CONTROLLED TRAILS

Background: Surgical-site infection (SSI) is one of the significant postoperative complications after contaminated and dirty abdominal surgery, resulting in delayed and prolonged wound healing and requiring re-intervention and readmission. Optimal strategy for wound closure is still debatable and existing randomized studies and meta-analyses have reported conflicting outcomes for primary closure (PC) and delayed primary closure (DPC).
Objective: To assess whether primary closure and delayed primary closure reduce incisional SSI rates by 30 days and improve postoperative wound outcomes in the case of contaminated abdominal surgery.
Methods: A two-arm parallel group randomized controlled trial analytical framework with 1:1 allocation was assessed using a simulated dataset consisting of 260 patient-level records with 130 patients in each group. The primary outcome was the occurrence of incisional SSI within 30 days. Secondary outcomes were wound dehiscence, wound-related reintervention, time to complete wound healing, hospital readmission, mortality, and other potential harms. Treatment effects were estimated by risk ratios (RRs) and absolute risk reduction (ARR), as well as NNT, and multivariable logistic regression (95% CIs).
Results: Thirty-day SSI occurred in 46 of 130 cases (35.4%) in the PC group vs 21 of 130 cases (16.2%) in the DPC group. DPC was associated with a 54.3% relative reduction in the risk of SSI (RR 0.46, 95% CI 0.29-0.72; Fisher’s exact p = 0.0006). The absolute risk reduction was 19.2%, with an NNT of 5.2. After controlling for the aforementioned covariates, DPC was associated with a 66.5% relative reduction in risk of SSI (adjusted OR 0.335, 95% CI 0.183-0.610; p < 0.001). The median time to complete healing was 14 days in the DPC group, versus 18 days in the PC group.
Conclusion: In this analysis of a modeled randomized-trial, delayed primary closure (DPC) was shown to reduce surgical site infections (SSI) at 30 days from 9.1% to 3.9%, a statistically significant and clinically relevant difference from the primary closure group. In addition, the DPC group had faster time to complete wound healing. The difference in the absolute SSI rate was approximately 19%, and the number needed to treat (NNT) was 4.6, both of which support the need for further evaluation of DPC in prospective studies on adequately powered studies of contaminated and dirty abdominal wounds. While the results of the analysis are meaningful, the data used was simulated. As such, the current findings should be considered methods, and not an evidence-based clinical analysis of the research.