Table 1.

Definitions of complications

Complications	Definition
Pseudocysts	Fluid-filled collection in the pancreas without epithelial cover proven by CT.
Duodenum obstruction	Clinical symptoms suggestive of duodenal obstruction (retention, nausea, vomiting) and imaging evidence of duodenum obstruction by the pancreas.
Chronic use of opioids	Daily need for strong opioids for a period > 6 months.
(Acute) pancreatitis flare-up	Episode of upper abdominal pain requiring hospitalization with either increased amylase (>3 normal level) or typical upper abdominal pain recognized by patient from previous episodes.
Cholangitis	1) Body temperature > 38.5°C and 2) Bilirubin > 20 μmol/L and/ or common bile duct of > 8 mm for age ≤ 75 years or > 10 mm for age > 75 years on abdominal ultrasound or CT.
Acute cholecystitis	1) Local signs of inflammation (Murphy’s sign, right upper quadrant mass/pain/tenderness), 2) Systemic signs of inflammation (Fever, elevated CRP, elevated WBC) and 3) Gallstones on abdominal ultrasound.
Perforation	Retroperitoneal or bowel-wall perforation documented by any radiographic technique.
Anastomotic leakage: Pancreaticojejunostomy	High amylase level (>3 times serum amylase) in the abdominal drain fluid, or pancreatic leakage proven by imaging or at relaparotomy, often but not necessarily in combination with one or more clinical signs (abdominal pain, peritoneal tenderness, temperature above 38.5°C or WBC above 15 X 109/l).
Anastomotic leakage: biliary leakage	Bilirubin in abdominal drain or dehiscence found at laparotomy, often but not necessarily in combination with one or more clinical signs (abdominal pain, peritoneal tenderness, temperature above 38.5°C or WBC above 15 x 109/l).
Bleeding/ Hemorrhage	Any bleeding leading to relaparotomy or intervention.
Sepsis	Presence of two or more of the following: fever or hypothermia, leucocytosis or leucopenia, tachycardia, and tachypnea or a supernormal minute ventilation.
Intra-abdominal abscesses	Intra-abdominal fluid collection with positive cultures identified by ultrasonography or CT, associated with persistent fever and elevations of white blood cells.
Burst abdomen	Post-operative separation of the abdominal musculo-aponeurotic layers with protruding viscera.
Pneumonia	Combination of clinical signs (coughing, dyspnoea), with infiltrative abnormalities on chest X-ray, raised inflammatory parameters (WBC and CRP) and/or positive culture in sputum. In intubated patient a positive endotracheal culture is mandatory.
Severe wound infection	Infection occurring within 30 days after the operative procedure, and requiring hospitalization or intervention with subsequent prolonged hospital stay (otherwise considered as minor complication).
Severe delayed gastric emptying	Persistent need for nasogastric intubation of over 10 days or inability to tolerate solid diet on or after the 14th postoperative day.

CT: computed tomography. WBC: white blood cell count. CRP: C-reactive protein.