Conversion to open surgery during robotic pancreatoduodenectomy in surgical high-risk groups: patterns, risk factors, and outcomes in elderly and/or obese patients

Background: Conversion to laparotomy during robotic pancreatoduodenectomy (RPD) carries important clinical implications, yet its incidence, predictors, and consequences in elderly and/or obese patients remain poorly characterized. This study aimed to define the conversion rate, identify preoperative predictors, and assess the impact of conversion on postoperative outcomes in elderly and/or obese surgically high-risk patients undergoing attempted RPD. Methods: A retrospective analysis was performed using a multi-institutional database. Patients were included if they underwent attempted RPD and met at least one high-risk criterion: age ≥ 80 years and/or BMI ≥ 30 kg/m2. Conversion was defined as any unplanned transition from robotic to open surgery after initiation of the robotic procedure. Reasons for conversion were assigned using a hierarchical, mutually exclusive framework: intraoperative complication, patient instability, vascular involvement, or strategic surgeon decision. Results: Among 311 patients, 36 (11.6%) required conversion to laparotomy. The most common recorded reason was strategic surgeon decision (n = 18, 50.0%), followed by vascular involvement (n = 10, 27.8%), intraoperative complications, and patient instability. On multivariable analysis, independent predictors of conversion were preoperative biliary drainage (OR 7.36; p = 0.021) and vascular involvement (OR 22.22; p = 0.027), while male sex was protective (OR 0.22; p = 0.032). Robotic experience > 20 cases was associated with reduced conversion risk in an adjusted model (aOR 0.17; p = 0.027). Conversion was associated with longer hospital stay, higher 30-day and 90-day mortality, and increased postoperative complications. Clinically relevant postoperative pancreatic fistula rates were similar between groups overall. Conclusions: In elderly and/or obese surgically high-risk patients selected for attempted RPD, conversion occurred in approximately one in nine cases and was associated with worse short-term outcomes. These findings support careful patient selection, recognition of vascular complexity, transparent counseling, and a low threshold for strategic conversion in expert robotic pancreatic programs. Conversion should not be interpreted uniformly as operative failure, because its implications differ according to mechanism and timing.