Latest Definition of Postoperative Pancreatic Fistula (POPF)
The latest definition of postoperative pancreatic fistula according to the 2016 update from the International Study Group of Pancreatic Surgery (ISGPS) is a drain output of any measurable volume of fluid with an amylase level >3 times the upper limit of institutional normal serum amylase activity, associated with a clinically relevant development/condition related directly to the postoperative pancreatic fistula. 1
Key Changes in the Updated Definition
- The former "Grade A postoperative pancreatic fistula" has been redefined as a "biochemical leak" and is no longer considered a true pancreatic fistula since it has no clinical importance 1
- Only clinically relevant fistulas (former Grades B and C) are now classified as true postoperative pancreatic fistulas 1
- The definition requires both biochemical evidence (elevated amylase) AND clinical relevance for diagnosis 1, 2
Current Grading System
Biochemical Leak (formerly Grade A)
- Drain fluid with amylase >3 times upper limit of normal serum amylase 1
- No clinical impact or change in management 1
- Drains typically removed within 3 weeks 1, 2
Grade B POPF
- Requires a change in postoperative management 1
- Drains left in place >3 weeks or repositioned through endoscopic or percutaneous procedures 1
- May be associated with signs of infection but manageable without reoperation 2
- Often requires adjusted clinical pathway (antibiotics, artificial nutrition, etc.) 2
Grade C POPF
- Requires reoperation 1
- Leads to single or multiple organ failure and/or mortality attributable to the pancreatic fistula 1
- Often associated with severe complications like postoperative bleeding or sepsis 3
- Mortality rate in Grade C POPF patients can reach approximately 39% 3
Diagnostic Criteria
- Amylase level in drain fluid >3 times upper limit of normal serum amylase 1, 2
- Abnormal clinical course directly related to the pancreatic leak 2
- Some centers also measure lipase in drain fluid, though this adds minimal additional diagnostic value (only 2% additional cases detected) 4
- Diagnosis typically made on or after postoperative day 3 1, 2
Risk Factors for Severe POPF (Grade C)
- Soft pancreatic parenchyma 3
- Perioperative blood transfusion 3
- Postoperative bleeding 3
- Increased body mass index 4
Clinical Implications
- The updated classification allows for more precise comparisons of surgical quality between surgeons and institutions 1
- Early systematic detection of POPF using periodic assays and imaging when indicated can help prevent progression to severe forms 2
- Rapid minimally invasive treatment of collections (percutaneous drainage, antibiotic therapy) is recommended to prevent severe septic and/or hemorrhagic complications 2
- Swift withdrawal of abdominal drains is advised when POPF risk is low and clinical evolution is favorable 2
This updated definition and grading system provides a more clinically relevant framework for evaluating outcomes after pancreatic surgery and comparing techniques used to mitigate the rate and impact of pancreatic fistulas.