Gallstone pancreatitis. Local predisposing factors.

Local predisposing anatomic and stone factors were studied in 150 patients with gallstones in order to analyze why some patients with cholelithiasis acquire gallstone pancreatitis and others do not. Number and size of gallstones in the gallbladder and common bile duct, presence of pancreatic duct reflux, diameter of the cystic duct, and size of the duodenal orifice and ampulla of Vater were all studied in 75 patients with gallstone pancreatitis (Group I), 75 patients with cholelithiasis (Group II), and by dissections in 50 autopsy specimens. Stones 5 mm or less in diameter were present in 51 (70%) of Group I gallbladders as compared to 30 (41%) of Group II patients (p less than 0.001). Impacted common bile duct stones were found in 21 (29%) of the Group I patients and only four (5%) of the patients in Group II (p less than 0.001). The mean size of the stones that impacted at the ampulla of Vater in the Group I patients were 3.10 mm, whereas in the Group II patients the mean size of the stones was 7.50 mm (p less than 0.001). The Group I cystic ducts were larger (3.80 mm) than the ducts in the Group II patients (2.36 mm) (p less than 0.001). On operative cholangiography, 50 (67%) showed reflux of contrast material into the pancreatic duct compared to only 14 (18%) in the control Group II (p less than 0.001). These data indicate that small gallbladder stones, enlarged cystic ducts, properly sized impacted stones, and a functioning common channel are predisposing local etiologic factors in the development of gallstone pancreatitis.