Robotic versus open hepatectomy for IWATE expert-level liver resection: a risk-adjusted comparative study.

BACKGROUND: Evidence directly comparing robotic and open hepatectomy for IWATE expert-level liver resection remains limited. This study aimed to compare perioperative outcomes between the two approaches in a high-volume hepatobiliary center. METHODS: We reviewed 1706 consecutive patients who underwent hepatectomy for intrahepatic lesions between January 2024 and December 2025. Among them, 232 patients met the criteria for IWATE expert-level resection, including 70 robotic and 162 open cases. The primary outcome was major complications, defined as Clavien-Dindo grade ≥III. One-to-one propensity score matching was used as the primary risk-adjustment method. Overlap weighting was performed as a sensitivity analysis, with an additional malignancy-restricted analysis. Exploratory subgroup analyses were conducted for major complications and textbook outcome in liver surgery (TOLS). RESULTS: Propensity score matching yielded 68 well-balanced pairs. In the matched cohort, robotic hepatectomy had longer operative time than open hepatectomy (median, 240.0 vs 205.5 min; P = 0.002), but lower estimated blood loss (100.0 vs 200.0 mL; P = 0.038) and shorter postoperative length of stay (6.0 vs 9.0 days; P < 0.001). Major complications were comparable between the robotic and open groups (13.2% vs 19.1%; P = 0.480). TOLS and severe liver-specific complications were also similar between groups. No significant between-group difference was observed in 90-day mortality. Findings from the overlap-weighted and malignancy-restricted analyses were directionally consistent with the primary analysis. In exploratory subgroup analyses, no significant interaction was observed across most prespecified subgroups, whereas a significant interaction with cirrhosis was detected for both major complications and TOLS. CONCLUSIONS: Robotic hepatectomy was associated with reduced blood loss and shorter postoperative stay without increased major morbidity or mortality in selected patients undergoing IWATE expert-level liver resection at an experienced center. These findings support the selective application of robotic hepatectomy in technically demanding liver resections.