To confirm the time point of CR-POPF of grade-B that patients with biochemical leak after PD or LPD turned into.

1. To confirm the time point of CR-POPF of grade-B that patients with biochemical leak after PD or LPD turned into.
2. Establishment of risk assessment model for Grade B fistula.

Inclusion Criteria:

• Patients underwent Pancreatoduodenectomy (PD) or Laparoscopic pancreatoduodenectomy (LPD) surgery.
• Surgery performed by the same surgical team.

Exclusion Criteria:

• PD or LPD combined with another organ resection.
• PD or LPD performed due to trauma.
• PD or LPD for emergency treatment, such as the rupture and bleeding of tumor.
• Palliative resection.
• Patients with severe organ dysfunction before surgery.
• Patients treated with preoperative neoadjuvant chemotherapy or other treatments (Radiotherapy, targeted immunotherapy, etc.).
• Patients with missing data for clinical or radiographic variables.

(1) Patients with PD or LPD surgery; (2) Surgery performed by the same surgical team.