Proposal of a revised 3-tier "2 mm" risk classification model for postoperative pancreatic fistula in robotic pancreatoduodenectomy

Abstract

Background: The recent International Study Group for Pancreatic Surgery (ISGPS) risk classification for postoperative pancreatic fistula (grade B/C) was developed based on data from open and mixed minimally invasive pancreatoduodenectomy. The ISGPS risk classification model has not been validated specifically for POPF after robotic pancreatoduodenectomy (RPD).

Methods: We calculated the rate of POPF (ISGPS 2016 definition, grade B/C) by analyzing consecutive patients after RPD by surgeons after their learning curves (80 RPDs per surgeon). The validation of the ISGPS 4-tier and the simplified 3-tier risk classification was conducted using the area under the receiver operating curve (AUC).

Results: From 2019 to 2023, 187 patients after RPD were included. Neither the ISGPS 4-tier nor the simplified 3-tier classification model showed robust discrimination (AUC: 0.696 and 0.685, respectively). Moreover, both risk classifications failed to differentiate the rates of POPF and major complications among subgroups. Multivariate analysis suggested that soft pancreatic texture and pancreatic duct ≤ 2 mm were independent risk factors for POPF after RPD. After adjusting the duct size's cutoff from 3 to 2 mm, the revised 4-tier "2 mm" classification model showed no significant difference between risk categories B and C (6.7% vs. 9.4%, P = 0.063). The revised 3-tier "2 mm" classification model stratified patients into A (n = 54), B (n = 68), and C (n = 65) groups, with corresponding POPF rates of 0.0%, 8.8%, and 23.1% (P < 0.001), and major complication rates of 5.6, 14.7, and 24.6% (P = 0.014), respectively. Compared to the simplified 3-tier classification model, the revised 3-tier "2 mm" classification model showed improved discrimination (AUC: 0.753 vs. 0.685, P = 0.034) and clinical utility.

Conclusions: The current ISGPS 4-tier and the simplified 3-tier classification models lacked sufficient discrimination in patients after RPD. We propose a revised 3-tier "2 mm" risk classification model for RPD with a robust discrimination, which requires further international validation with prospectively obtained data.

Keywords: Pancreatic fistula; Pancreatoduodenectomy; Risk factors; Robotic pancreatectomy.