Minimally invasive treatment of colorectal liver metastases: does robotic surgery provide any technical advantages over laparoscopy? A multicenter analysis from the IGoMILS (Italian Group of Minimally Invasive Liver Surgery) registry

Surgery has been the mainstay treatment for colorectal liver metastases (CRLM). Although the benefits of a laparoscopic approach have been evidenced by several comparative studies, the comparison between robotic and laparoscopic liver surgery has not been elucidated. Thus, in this study, we aim to analyze the short-term outcomes of a multicenter population that underwent robotic versus laparoscopic liver resection for CRLM. Consecutive patients with CRLM who were enrolled in the IGoMILS registry between November 2014 and June 2019 were retrospectively evaluated to compare robot-assisted procedures with laparoscopic procedures. Primary outcomes were postoperative morbidity and mortality, while secondary outcomes were length of hospital stay, operative time, and histological features of the surgical specimen. The effect size of surgical technique on resection margins was quantified using Hedges' g. In total, 1030 patients underwent minimally invasive liver surgery (MILS) for CRLM; of these, 77 (7.5%) underwent a robot-assisted approach (R-MILS), whereas 953 (92.5%) underwent a laparoscopic approach (L-MILS). Laparoscopy and robot-assisted surgery were comparable in terms of postoperative outcomes: specifically, complication rates, Comprehensive Complication Index (CCI(R)), intraoperative blood loss, conversion rate, operative time, and length of hospital stay did not differ significantly between the two groups. R-MILS showed a reduced rate of R1 resection margins (19.9 vs. 28.8%, p = 0.025) and wider surgical margins compared with L-MILS (8 vs. 3 mm, p < 0.001). The effect size of robot-assisted surgery was increased for posterosuperior lesions (g = 0.78) and difficult procedures (g = 1.92). As per our findings, it was determined that robot-assisted liver surgery offers some technical advantages over conventional laparoscopy, maintaining the benefits of minimally invasive surgery on short-term outcomes.