Comparison of short-term outcomes for robotic rectal surgery between the hinotori™ surgical robot system and da Vinci surgical system: a single-center retrospective study using propensity score matching analysis

Background: Robotic surgery for rectal cancer has grown popular in recent years and has primarily used the da Vinci Surgical System (Intuitive Surgical, CA, USA; da Vinci). In 2020, Japan introduced the hinotori™ Surgical Robot System (Medicaroid, Kobe, Japan; hinotori). We report our initial surgical experiences with robotic surgery using hinotori for rectal cancer and its feasibility and safety comparing with da Vinci. Methods: A single-institution retrospective study was conducted. Between November 2022 and November 2023, 38 and 96 patients with rectal cancer underwent robotic surgery using hinotori and da Vinci, respectively. The primary endpoint was the incidence of postoperative complications of the Clavien–Dindo classification (CD) grade ≥ II within postoperative 30 days. Secondary endpoints included surgical and console time, blood loss, conversion to other approaches, number of dissected lymph nodes, and postoperative hospital stay. A propensity score matching (PSM) analysis was used to adjust for imbalance in baseline characteristics. Results: After PSM, a total of 76 patients (hinotori: 38, da Vinci: 38) were included. Compared to the da Vinci group, the hinotori group showed a similar postoperative complication rate of CD ≥ II (15.8% vs. 18.4%), comparable operative time (280.5 vs. 258 min), comparable console time (166 vs. 156 min), and less blood loss (9 vs. 17.5 mL, p = 0.025). There was no conversion in either group. The number of dissected nodes and postoperative stay were similar between the two groups. Conclusion: Our findings support that robotic surgery for rectal cancer using hinotori is as safe as surgery performed using the da Vinci system.