Comparison of superficial surgical site infection between delayed primary versus primary wound closure in complicated appendicitis: a randomized controlled trial

Objective: To compare superficial surgical site infection (SSI) rates between delayed primary wound closure (DPC) and primary wound closure (PC) for complicated appendicitis. Background: SSI is common in appendectomy for complicated appendicitis. DPC is preferentially used over PC, but its efficacy is still controversial. Methods: A multicenter randomized controlled trial was conducted in 6 hospitals in Thailand, enrolling patients with gangrenous and ruptured appendicitis. Patients were randomized to PC (ie, immediately wound closure) or DPC (ie, wound closure at postoperative days 3-5). Superficial SSI was defined by the Center for Disease Control criteria. Secondary outcomes included postoperative pain, length of stay, recovery time, quality of life, and cost of treatment. Results: In all, 303 and 304 patients were randomized to PC and DPC groups, and 5 and 4 patients were lost to follow-up, respectively, leaving 300 and 298 patients in the modified intention-to-treat analysis. The superficial SSI rate was lower in the PC than DPC groups [ie, 7.3% (95% confidence interval 4.4, 10.3) vs 10% (95% CI 6.6, 13.3)] with a risk difference (RD) of -2.7% (-7.1%, 1.9%), but this RD was not significant. Postoperative pain, length of stay, recovery times, and quality of life were nonsignificantly different with corresponding RDs of 0.3 (-2.5, 3.0), -0.1 (-0.5, 0.3), -0.2 (-0.8, 0.4), and 0.02 (-0.01, 0.04), respectively. However, costs for PC were 2083 (1410, 2756) Baht cheaper than DPC (~$60 USD). Conclusions: Superficial SSI rates for the PC group were slightly lower than DPC group, but this did not reach statistical significance. Costs were significantly lower for the PC group.