Study - International multicentric minimally invasive liver resection (SIMMILR-4) : a comparison of conventional, digitally enhanced and collaborative robotic with Tele-robotic laparoscopic surgery for colorectal liver metastases

This international multicenter study compared five surgical approaches for resection of colorectal liver metastases (CRLM): open, conventional laparoscopy (L), digitally enhanced laparoscopy with 3D imaging (DEL), collaborative robotic laparoscopy with a single robotic arm (CRL) with tele-robotic laparoscopic surgery with 3D imaging and 4 robotic arms (TRL). This exploratory study aimed to assess whether TRL liver resection for colorectal liver metastases (CRLMs) demonstrates potential advantages over conventional laparoscopy (L), digitally enhanced laparoscopy (DEL), or collaborative robotic laparoscopy (CRL). A retrospective analysis of 1,257 patients undergoing CRLM resection across five centers was performed. Surgical techniques were classified as O, L, DEL, CRL, or TRL. Because of limited case numbers in the DEL, CRL, and TRL groups, the primary comparison was between all minimally invasive surgery (MIS) cases combined (L, DEL, CRL, TRL; n = 283) and matched open controls (n = 283) using 1:1 propensity score matching. Outcomes included estimated blood loss (EBL), operative time, length of stay (LOS), resection margin status (R0), and major complications (Clavien-Dindo grade ≥ 3). MIS demonstrated significantly lower EBL (505 mL vs. 692 mL, p < 0.0001) and shorter LOS (8 vs. 14 days, p < 0.0001) compared with open surgery. Subgroup analyses of DEL, CRL, and TRL (each < 21 patients post-match) showed comparable perioperative outcomes, suggesting incremental adoption of advanced technologies did not compromise safety or efficiency. MIS offers significant reductions in blood loss and hospital stay compared with open surgery. While TRL provides technical advantages, it did not show clear superiority. Prospective standardized multicenter studies are needed to confirm these exploratory findings.