Phase-specific operative times in robotic distal pancreatectomy: impact of body mass index and learning experience

Robotic distal pancreatectomy (RDP) in obese patients is technically demanding, but the phase-specific impact of body mass index (BMI) remains unclear.

We analyzed 164 patients who underwent RDP with splenectomy between October 2018 and September 2025. Twelve surgical phases were predefined, and all recorded frames were assigned to one phase. Based on the lead surgeon's cumulative sum (CUSUM) curve, the learning period was defined as the first 34 cases. Multivariable linear regression identified determinants of total operative time, and associations between BMI and phase durations were tested.

Median operative time was 269 min. The learning period and BMI ≥30 independently prolonged operative time, with a larger effect in men than in women (β = 59.8 vs 37.5 min; both P < 0.05). After the learning period, phase durations decreased in "greater curvature dissection and splenic flexure mobilization" and "pancreatic tunneling with encircling" (46.6 vs 23.0 min and 13.8 vs 8.5 min; both P < 0.001). In men, higher BMI was associated with longer durations in these phases (β = 2.0 and 1.0 min per BMI unit, respectively), whereas no significant association was observed in women.

Targeted proctoring of these two phases, particularly for obese male patients, may help surgeons maintain efficiency during RDP implementation.