Abstract
<title>Abstract</title> <p>Objective To explore the learning curve (LC) of robot-assisted hepatectomy (RAH) for the treatment of malignant liver tumors and investigate its relevant patterns, so as to provide guidance for the safe clinical implementation of this surgery. Methods A retrospective analysis was conducted on the clinical data of 184 patients who received treatment in the Department of General Surgery, Sir Run Run Shaw Hospital Affiliated to Zhejiang University School of Medicine from March 2016 to April 2025, and underwent RAH performed by the same chief surgeon. The Iwate scoring system was used to classify the surgical difficulty. The cumulative sum method (CUSUM) was applied to analyze the learning curves of different surgical difficulty levels. The learning curve was verified by comparing the general data and short-term clinical outcomes of patients in different learning stages, and the impact of different learning stages on patients' clinical efficacy was explored. Results A total of 184 consecutive patients with malignant liver tumors who underwent RAH were included in the study. Among them, 141 were male (76.6%) and 43 were female (23.4); the age was 62.5 (62.0 ± 11.9) years, the body mass index (BMI) was 23.0 (23.4 ± 3.4) kg/m2, and the Child-Pugh score was 5.0 (5.1 ± 0.3). In addition, 55 patients (29.7%) had liver cirrhosis. The operative time was 172.5 (185.2 ± 72.7) minutes, the intraoperative blood loss was 100.0 (164.3 ± 325.3) mL, the tumor size was 32.5 (38.4 ± 23.3) mm, and the R0 resection margin rate reached 99.5%. The incidence of major postoperative complications was 1.6%, the postoperative hospital stay was 5.0 (5.4 ± 2.5) days, the 30-day readmission rate was 32.1%, the 30-day mortality rate was 0%, and the 90-day mortality rate was 0%.There was a statistically significant difference in operative time among the four Iwate grade groups (P < 0.001). Patients with an Iwate score ≤ 6 were classified into the low-difficulty group, while those with an Iwate score > 6 were classified into the high-difficulty group. Conclusion The cumulative sum method (CUSUM) analysis showed that the learning curve of RAH consists of two phases: the improvement phase and the maturation phase. The learning curve for hepatectomy in the low-difficulty group included 32 cases, while that in the high-difficulty group included 33 cases.</p>