Factors Associated with and Impact of Open Conversion in Laparoscopic and Robotic Minor Liver Resections: An International Multicenter Study of 10,541 Patients

Introduction: Despite the increasing widespread adoption and experience in minimally invasive liver resections (MILR), open conversion occurs not uncommonly even with minor resections and as been reported to be associated with inferior outcomes. We aimed to identify risk factors for and outcomes of open conversion in patients undergoing minor hepatectomies. We also studied the impact of approach (laparoscopic or robotic) on outcomes. Methods: This is a post-hoc analysis of 20,019 patients who underwent RLR and LLR across 50 international centers between 2004–2020. Risk factors for and perioperative outcomes of open conversion were analysed. Multivariate and propensity score-matched analysis were performed to control for confounding factors. Results: Finally, 10,541 patients undergoing either laparoscopic (LLR; 89.1%) or robotic (RLR; 10.9%) minor liver resections (wedge resections, segmentectomies) were included. Multivariate analysis identified LLR, earlier period of MILR, malignant pathology, cirrhosis, portal hypertension, previous abdominal surgery, larger tumor size, and posterosuperior location as significant independent predictors of open conversion. The most common reason for conversion was technical issues (44.7%), followed by bleeding (27.2%), and oncological reasons (22.3%). After propensity score matching (PSM) of baseline characteristics, patients requiring open conversion had poorer outcomes compared with successful MILR cases as evidenced by longer operative times, more blood loss, higher requirement for perioperative transfusion, longer duration of hospitalization and higher morbidity, reoperation, and 90-day mortality rates. Conclusions: Multiple risk factors were associated with conversion of MILR even for minor hepatectomies, and open conversion was associated with significantly poorer perioperative outcomes.