Clinical and biological impact of conversion on outcomes of minimally invasive liver surgery: a multimodal analysis

Minimally invasive liver surgery (MILS) offers several advantages over open liver surgery (OLS), but the underlying mechanisms remain unclear. This study compares inflammatory marker levels between OLS and MILS and examines the impact of conversion. Patients undergoing liver resection at San Raffaele Hospital (September 2022–May 2023) were prospectively enrolled. Plasma inflammatory markers were measured over 120 postoperative hours and analyzed between cohorts. Among 118 liver resections (50 laparoscopic, 38 robotic, 30 open), the OLS group showed higher intraoperative plasma lactate (4.6 vs. 3.8 mmol/L; p < 0.04) and levels one hour postoperatively (3.9 vs. 2.4 mmol/L; p = 0.02). CRP and IL-6 levels were significantly higher in OLS (p < 0.001). No significant differences were found between laparoscopic and robotic approaches. However, conversion led to increased lactate (p = 0.018), CRP (p < 0.05), and IL-6 (p < 0.001) also compared with upfront OLS. MILS significantly improves biological markers as compared to OLS. However, conversion not only negates these benefits but also amplifies surgical stress and inflammation.