Development of Predictive Models for Post-Pancreaticoduodenectomy Pancreatic Fistula: A Preliminary Comparative Study of Internal versus External Drainage Systems

Abstract Purpose This study analyzes risk factors for postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) across different pancreatic fluid drainage techniques, aiming to inform surgical strategy selection, clinical interventions, and complication prevention. Methods A total of 273 patients who underwent PD were included. They were divided into pancreatic fistula and non-fistula groups, and a predictive model for POPF was developed and validated. Patients were then further classified into internal and external drainage groups. Separate POPF prediction models were built for each group to identify group-specific risk factors. Results The risk factors associated with POPF in all patients undergoing PD include: a body mass index (BMI) > 25 kg/m², biliary drainage, blood transfusion and invagination pancreaticojejunostomy (IPJ) ( P < 0.05). Patients in the non-fistula group demonstrated significantly lower postoperative levels of biochemical tests, as well as a reduced duration of abdominal drainage and shorter hospital stays ( P < 0.05). Furthermore, variables that were significantly associated with POPF among patients in the internal drainage groups included: BMI > 25 kg/m², blood transfusion and IPJ; conversely, for external drainage groups, significant associations were identified with biliary drainage and blood transfusion ( P < 0.05). The predictive model exhibited acceptable predictive capability as indicated by the Hosmer-Lemeshow (H-L) test results: H-L test = 0.071 and area under the curve (AUC) = 0.684 for internal drainage groups; H-L test = 0.131 and AUC = 0.743 for external drainage groups. Conclusion BMI > 25 kg/m², blood transfusion and IPJ are recognized as independent risk factors for POPF. In patients with a BMI > 25kg/m², undergoing internal drainage and invagination pancreaticojejunostomy may elevate the incidence of POPF; conversely, external drainage does not exhibit a significant impact. Therefore, in clinical practice, for obese patients with a BMI > 25kg/m²—particularly those presenting additional risk factors—it is advisable to consider external drainage and to perform pancreaticojejunostomy utilizing a duct-to-mucosa approach. This strategy may contribute to a reduction in the incidence of POPF and facilitate postoperative recovery in these patients.