Prevention of Liver-related Surgical Site Infections in Combined Liver and Colorectal Surgery

Objective: Evaluate the role of short-course (72h) postoperative antibiotic prophylaxis (PPA) in reducing liver-specific surgical site infections (liver-SSI) incidence. Summary Background Data: Simultaneous liver and colorectal resections (SLCR) represent a valid oncologic strategy for colorectal liver metastases, however, this approach has been reported to increase the risk of postoperative liver-SSIs. Methods: Patients undergoing SLCR (2012-2024) in two tertiary centers were included and divided into two groups: patients receiving intraoperative antibiotic prophylaxis alone (IPA) and those receiving additional PPA. Outcomes included liver-SSI incidence, severe morbidity (Clavien-Dindo grade III-IV), and length of hospital stay. Matching (PSM) and Inverse Probability Treatment Weigthing (IPTW) on a propensity score and mixed-effects models were employed to adjust for confounders and center-level clustering. We tested for interactions with the liver resection approach (laparoscopy-laparotomy) and extend (major-minor). Results: Of 250 patients (median [95%CI] age: 67.0 years [65.0-68.0], 58.0% men), 40% (n=100) received PPA. Liver-SSI was significantly less frequent in the PPA group (11% vs. 29.3%; P <0.001), with consistent results across centers and across resection approach (p interaction =0.451) and extend (p interaction =0.490). The PPA group experienced shorter hospital stay (8.0 days [7.0-10.0] vs. 11.0 days [9.0-12.0], P =0.045) and fewer severe complications (15% vs. 29.3%, P =0.01). PPA was independently associated with a reduced risk of liver-SSI before (OR: 0.24, 95%CI:0.09–0.57, P =0.002) and after matching (OR PSM : 0.27, 95%CI: 0.09-0.73, P =0.014) and IPTW (OR IPTW : 0.27, 95%CI: 0.15–0.47, P <0.001). Conclusions: PPA is associated with a significant liver-SSI reduction following SLCR and our findings support its use, warranting further validation in prospective randomized studies.