Graduated Autonomy of Laparoscopic Liver Resection Based on Liver Resection Complexity: a Western and Eastern Bi-Institution Study for Learning Curve

BACKGROUND: Laparoscopic liver resection (LLR) requires a high degree of expertise in both hepatobiliary and minimally invasive surgery. Our group previously reportwed a 3-level LLR complexity classification based on intrapostoperative outcomes: grade I (low), grade II (intermediate), and grade III (high). We evaluated the learning curve effect in each complexity grade to assess the experience needed for a surgeon to safely progress through the grades. STUDY DESIGN: Patients who underwent LLR during 1994 to 2020 at the Institut Mutualiste Montsouris and the University of Tokyo during 2008 to 2023 were included in the study. The learning curve for operating time was evaluated using the standardized (cumulative sum) analysis for each complexity grade. RESULTS: A total of 503 patients (grade I, 198; grade II, 87; and grade III, 218) at the Institut Mutualiste Montsouris and 221 patients (grade I, 135; grade II, 57; and grade III, 29) at the University of Tokyo met the inclusion criteria. The cumulative sum analysis showed that the deviation of operating time was found up to 40 cases for grade I resections, 30 cases for grade II resections, and 50 cases for grade III resections. By dividing cohorts based on these numbers for each group and each institution and labeling these cases as the prelearning groups and the remaining as the postlearning group, surgical outcomes and postoperative complications were generally improved in the postlearning groups in both institutions. CONCLUSIONS: A gradual progression in LLR per complexity grade as follow: 40 cases of low grade I procedures before starting intermediate complexity grade II procedures, and 30 cases of intermediate complexity grade II procedures before starting high complexity grade III procedures may ensure a safe implementation of high complexity LLR procedures.