The impact of liver transection depth on surgical difficulty in robotic versus laparoscopic limited liver resection (TAKUMI-5).

PURPOSE: Although robotic liver resection (RLR) has gained popularity worldwide, limited liver resection remains the mainstay of RLR. This study aimed to investigate the effect of parameters, including liver transection depth (LTD), on surgical difficulty in limited RLR compared with limited laparoscopic liver resection (LLR). METHODS: This retrospective study included 105 patients who underwent limited RLR (n = 56) or LLR (n = 49) at our institution between January 2018 and December 2024. After comparing outcomes of RLR and LLR, multivariate analyses were performed to examine effect of LTD on surgical difficulty (defined as prolonged operative time). Moreover, outcomes stratified by LTD cut-off values were compared between the groups. RESULTS: Median LTD was similar between groups (RLR vs. LLR: 2.6 vs. 2.6 cm, P = 0.77). LTD was significantly correlated with operative time for both procedures (RLR, R² = 0.07, P = 0.042; LLR, R² = 0.08, P = 0.046). Multivariate analyses demonstrated that LLR (odds ratio, 6.9; P < 0.001) and LTD (odds ratio, 2.0; P = 0.004) were significant risk factors of surgical difficulty. Among patients with deeper LTD (> 2.5 cm), the RLR group had significantly shorter operative time (145 vs. 231 min, P < 0.001), less blood loss (nil vs. 100 mL, P = 0.006), and a higher rate of textbook outcomes (76.7% vs. 42.3%, P = 0.01). CONCLUSION: This study investigated impact of LTD on surgical outcomes in patients who underwent limited RLR compared to those who underwent limited LLR. LTD may be a useful parameter for estimating surgical difficulty in limited RLR. Moreover, robotic surgery may be favorable for deeper and limited liver resections.