Sub‐classification of laparoscopic left hepatectomy based on hierarchic interaction of tumor location and size with perioperative outcomes.

Background: The aim of this multicentric study was to investigate the impact of tumor location and size on the difficulty of Laparoscopic‐Left Hepatectomy (L‐LH). Methods: Patients who underwent L‐LH performed across 46 centers from 2004 to 2020 were analyzed. Of 1236 L‐LH, 770 patients met the study criteria. Baseline clinical and surgical characteristics with a potential impact on LLR were included in a multi‐label conditional interference tree. Tumor size cut‐off was algorithmically determined. Results: Patients were stratified into 3 groups based on tumor location and dimension: 457 in antero‐lateral location (Group 1), 144 in postero‐superior segment (4a) with tumor size ≤40 mm (Group 2), and 169 in postero‐superior segment (4a) with tumor size >40 mm (Group 3). Patients in the Group 3 had higher conversion rate (7.0% vs. 7.6% vs. 13.0%, p‐value.048), longer operating time (median, 240 min vs. 285 min vs. 286 min, p‐value <.001), greater blood loss (median, 150 mL vs. 200 mL vs. 250 mL, p‐value <.001) and higher intraoperative blood transfusion rate (5.7% vs. 5.6% vs. 11.3%, p‐value.039). Pringle's maneuver was also utilized more frequently in Group 3 (66.7%), compared to Group 1 (53.2%) and Group 2 (51.8%) (p =.006). There were no significant differences in postoperative stay, major morbidity, and mortality between the three groups. Conclusion: L‐LH for tumors that are >40 mm in diameter and located in PS Segment 4a are associated with the highest degree of technical difficulty. However, post‐operative outcomes were not different from L‐LH of smaller tumors located in PS segments, or tumors located in the antero‐lateral segments. [ABSTRACT FROM AUTHOR]