How long is long enough to identify a surgical site infection?

Abstract

Background: The U.S. Centers for Disease Control requires 90 days after surgery using an implant to diagnose or show the absence of a surgical site infection (SSI). However, many databases only track outcomes up to 30 days. The cost and effort to increase follow-up to 90 days after surgery is high and the benefit is unclear. We hypothesize that the majority of SSIs after ventral hernia repair occur within 30 days of surgery. Patients and Methods: All patients who underwent ventral hernia repair (with or without mesh) from 2010-2015 at a single institution were evaluated for evidence of SSI. The duration between surgery and the diagnosis of a post-operative SSI was assessed. Baseline and operative characteristics were compared between patients with an early SSI (within 30 days of surgery) and those with a late SSI (more than 30 days after surgery). Results: Among 1,635 patients who underwent ventral hernia repair, 117 (7.2%) developed an SSI. The median (range) of days between surgery and SSI was 15 days (range, 2-763). There were 20 (17.1%) late SSIs diagnosed; of these, 17 were diagnosed between 31-90 d and three were diagnosed later than 90 days. Patients with a late SSI were more likely to have had a prior ventral hernia repair and have had biologic mesh (p = 0.001). Conclusions: Whereas the majority of SSIs after ventral hernia repair occurred within the first 30 days, a substantial number of late SSIs occurred. It is worthwhile to follow patients for at least 90 days post-operative in order to capture a more accurate picture of the true rate of SSI.