Abstract: Objective To investigate the effect of different balloon dilation time on the stone clearance rate, liver function, stress level and postoperative pancreatitis in elderly patients with bile duct stones undergoing endoscopic sphincterotomy (EST) of the duodenal papilla, so as to guide the optimal balloon dilation time in clinical practice. 
Methods A total of 116 elderly patients with bile duct stones were selected and divided into a 1-min group (n=58) and a 3-min group (n=58) according to the random number table method. Both groups received EST treatment, with balloon dilation times of 1 min and 3 min for the 1-min and 3-min groups, respectively. The general surgical conditions, stone removal, and liver function ［γ-glutamyltransferase (γ-GT), alanine aminotransferase (ALT), alkaline phosphatase (ALP), direct bilirubin (DBIL), total bilirubin (TBIL)］, stress level ［cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), cortisol (Cor)］, and complications of the two groups were compared. 
Results The duration of operation in the 3-min group was shorter than that in the 1-min group, and the intraoperative blood loss was lower than that in the 1-min group, showing significant difference (P＜0.05). There was no significant difference in length of postoperative hospital stay and X-ray exposure time between the 3-min group and the 1-min group (P＞0.05), as well as in the mechanical lithotripsy rate, one-time stone clearance rate and stone removal time between the 3-min group and the 1-min group (P＞0.05).At 1 d and 3 d after operation, γ-GT, ALP, ALT, DBIL and TBIL in the two groups showed a decreasing trend, and there were significant differences in interaction between groups, time points, and time points between groups (P＜0.05), but there was no significant difference between two groups (P＞0.05). COX-2 and TNF-α, CRP and Cor of the two groups at 1 d and 3 d after operation showed an increasing trend, and there were significant differences in interaction between time points, and time points between groups (P＜0.05), but there was no significant difference between the two groups (P＞0.05). The levels of serum amylase and lipase in two groups showed an increasing trend at 1 d and 3 d after operation, and the differences of interaction between time points and time points between groups were statistically significant (P＜0.05). The levels of serum amylase and lipase in the 3-min group were lower than those in the 1-min group at 1 d and 3 d after operation (P＜0.05). The incidence of pancreatitis and bleeding in the 3-min group was lower than that in the 1-min group, and the difference was statistically significant (P＜0.05). The difference between the incidence of biliary tract infection in the 3-min group and the 1-min group was not statistically significant (P＞0.05). 
Conclusion Intraoperative balloon dilation for 3 min in EST applied to elderly patients with bile duct stones can effectively reduce intraoperative bleeding, shorten the duration of operation, and effectively avoid the occurrence of pancreatitis and bleeding while ensuring the stone removal effect without affecting liver function and the degree of traumatic stress. 

Key words: gallstones, pancreatitis, endoscopic sphincterotomy of the duodenal papilla