Background: Necrotizing pancreatitis (NP) can involve the pancreatic parenchyma and/or the surrounding peripancreatic tissues. Parenchymal injury often results in pancreatic duct leak resulting in amylase-rich fluid collections, pseudocysts, and pancreatic fistula. Isolated peripancreatic necrosis involves the retroperitoneal and mesenteric fat without pancreatic ductal involvement. Operative débridement and drainage can be complicated by the need to externally control a pancreatic duct leak or fistula. These patients have prolonged hospital stays and often require multiple re-interventions. We hypothesized that patients with isolated peripancreatic necrosis (PERI) have improved outcomes compared to patients with pancreatic parenchyma necrosis (PANC) following operative débridement.Methods: Records of patients with NP based on contrast-enhance dual phase helical CT treated at our institution between January 2004 and December 2007 were reviewed retrospectively. Of 215 patients with NP, 138 (64%) required operative debridement. Preoperative CT scans were reviewed to classify the necrosis as isolated to peripancreatic tissues (PERI) or involving the pancreatic parenchyma (PANC). Outcome variables examined included demographics, perioperative morbidity (organ failure, infectious complications, pancreatic and GI fistula), length of hospital stay, need for reoperation, and subsequent re-admissions. Data are expressed as Means + S.E.M. Data were analyzed with Student t-test or Chi square test. P value of less than 0.05 was considered statistically significant.Results: Fifty-two patients (38%) had PERI and 86 patients (62%) had PANC. The groups did not differ in age, gender, etiology of pancreatitis, or time to initial debridement. Preoperative in-hospital mortality was similar (5.8% PERI vs. 4.7% PANC). Patient with PERI had a lower pancreatic fistula rate after initial debridement (36.5% PERI vs. 50% PANC). Other outcome variables are shown in the table. Conclusions: These data suggest that patients with peripancreatic necrosis have less complicated postoperative courses and lower perioperative morbidity rates than patients with pancreatic parenchymal necrosis. Patients with isolated peripancreatic necrosis also have fewer readmissions and subsequent reoperations. We conclude that patients with isolated peripancreatic necrosis have a better overall prognosis than those with pancreatic parenchymal necrosis.

	N	Initial Los (days)	Readmissions (#)	Reoperations (#)	Total LOS (days)	Morbidity (%)
PERI	52	23.4±1.9	1.3±0.2	0.03±0.02	28.2±3.1	77
PANC	86	24.0±2.4	2.2±0.2*	0.58±0.17*	45.0±3.7	90*
	*p<0.05 vs PERI