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

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).

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).

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.

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.