Workflow-oriented learning curve analysis of laparoscopic distal pancreatectomy: step-specific associations of operative maturation

The learning curve of laparoscopic distal pancreatectomy (LDP) has traditionally been assessed using global operative indicators such as operative time and blood loss. However, little is known about how technical performance evolves during individual operative steps. This study aimed to perform a workflow-oriented learning curve analysis of LDP using cumulative sum (CUSUM) methodology and step-specific operative assessment. We retrospectively analyzed 58 consecutive patients who underwent LDP between January 2023 and December 2025 at a high-volume pancreatic center. Operative workflow was divided into predefined operative steps according to anatomical landmarks. CUSUM analysis based on operative time was used to identify the transition from the initial phases to the proficiency phase. CUSUM analysis identified a transition point at approximately Case 29. Mean operative time decreased from 77 ± 13 min in the early phase to 54 ± 14 min in the late phase ( P < 0.001). The steepest reductions occurred during pancreatic mobilization (31 ± 10 vs. 17 ± 6 min, P < 0.001) and splenic vessel dissection (24 ± 9 vs. 12 ± 4 min, P < 0.001). Estimated blood loss also declined significantly (39 ± 18 vs. 21 ± 11 mL, P = 0.002), while postoperative pancreatic fistula rates and overall complication rates remained comparable between phases. In this cohort, reductions in operative time during LDP were concentrated in anatomically complex dissection steps rather than uniform acceleration of the entire procedure. Step-specific analysis describes temporal patterns that characterize technical change during minimally invasive pancreatic surgery.