Body weight-associated procedural bottlenecks in robot-assisted surgery for congenital biliary dilatation: a step-specific operative time analysis.

Adults and heavier patients undergoing robot-assisted surgery for congenital biliary dilatation may require longer operative times. This study used step-specific video analysis to identify where additional time accumulated and which components remained relatively stable across patient size. Fifty-five patients (32 children and 23 adults) were retrospectively analyzed. Operative videos were divided into seven predefined steps and unclassified time. Step-specific durations were compared between groups. Restricted cubic spline and segmented regression analyses explored relationships between body weight and step-specific operative time. Total operative time was longer in adults than in children (509.0 vs. 386.0 min; P < 0.001). Adults required longer times for access and preparation, the Kocher maneuver, pancreatic-side bile duct dissection, Roux-en-Y limb creation and mesenteric fixation, final procedural steps, and unclassified workflow time. Hepatic duct dissection and ductoplasty and hepaticojejunostomy times were similar between groups. Pancreatic-side dissection time was longer in patients with postoperative pancreatic fistulas than in those without it (83.0 vs. 73.0 min; P = 0.039). Segmented regression yielded an exploratory breakpoint estimate of 17.8 kg (95% confidence interval, 9.6-25.9 kg). Using 18 kg as a data-derived exploratory cutoff, patients weighing ≥ 18 kg had longer access, dissection, intestinal preparation, and workflow times, without significant differences in biliary reconstruction times. Longer operative times in adults and heavier patients were concentrated in access, pancreatic-side bile duct dissection, intestinal preparation, and workflow, with no significant difference in biliary reconstruction times. The fistula association and the breakpoint are hypothesis-generating findings that require external validation.