Learning curve of robot-assisted laparoscopic partial nephrectomy surgery via the transperitoneal approach: a CUSUM analysis

Robot-assisted laparoscopic partial nephrectomy (RALPN) has increasingly emerged as a primary minimally invasive surgical approach for managing renal masses. In China, most urologic surgeons lack experience in transperitoneal laparoscopic partial nephrectomy, and limited research exists on the learning curve for transperitoneal RALPN. This study applies cumulative sum (CUSUM) analysis to evaluate the learning curve, providing clinical suggestions. We recruited patients who underwent transperitoneal RALPN performed by a single surgeon between March 2017 and December 2023. The learning curve was evaluated using CUSUM analysis of operative time (OT). The curve's peak was used as the cutoff point to stratify patients for comparative analysis of clinical characteristics and perioperative outcomes. In addition, multivariate linear regression analysis was used to identify potential factors influencing OT. 119 patients were enrolled. The curve peaked at the 38th case and subsequently declined, dividing the patients into two groups: the learning phase (38 cases) and the mastery phase (81 cases). OT (115 vs. 150 min., P < 0.001), WIT (19 vs. 24 min., P < 0.001), and hospital stay (6 vs. 7 days, P = 0.005) were lower in the mastery phase. Tumor size (P = 0.027) and surgeon experience (P < 0.001) were identified as potential risk factors for OT. This study demonstrates that the learning curve for transperitoneal RALPN is relatively short. Comparative analysis of perioperative outcomes revealed superior outcomes during the mastery phase. These findings may serve as a benchmark for urologic surgeons' skill acquisition.