Learning curves in robot-assisted minimally invasive liver surgery at a high-volume center in Denmark: Report of the first 100 patients and review of literature.

Background and objective: Minimally invasive liver surgery is evolving worldwide, and robot-assisted liver surgery (RLS) can deliver obvious benefits for patients. However, so far no large case series have documented the learning curve for RLS.

Methods: We conducted a retrospective study for robotic liver surgery (RLS) from June 2019 to June 2022 where 100 patients underwent RLS by the same surgical team. Patients' variables, short-term follow-up, and the learning curve were analyzed. A review of the literature describing the learning curve in RLS was also conducted.

Results: Mean patient age was 63.1 years. The median operating time was 246 min and median estimated blood loss was 100 mL. Thirty-two patients underwent subsegmentectomy, 18 monosegmentectomies, 25 bisegmentectomies, and 25 major hepatectomies. One patient (1.0%) required conversion to open surgery. Five patients (5%) experienced postoperative major complications, and no mortalities occurred. Median length of hospital stay was 3 days. R0 resection was achieved in 93.4% of the malignant cases. The learning curve consisted of three stages; there were no significant differences in operative time, transfusion rate, or complication rate among the three groups. Postoperative complications were similar in each group despite an increase in surgical difficulty scores. The learning effect was highlighted by significantly shorter hospital stays in cohorts I, II, and III, respectively. The included systematic review suggested that the learning curve for RLS is similar to, or shorter, than that of laparoscopic liver surgery.

Conclusions: In our experience, RLS has achieved good clinical results, albeit in the short term. Standardization of training leads to increasing proficiency in RLS with reduced blood loss and low complication rates even in more advanced liver resections. Our study suggests that a minimum of 30 low-to-moderate difficulty robotic procedures should be performed before proceeding to more difficult resections.