Influence of endoscopic papillary balloon dilation and endoscopic sphincterotomy on sphincter of Oddi function: A Randomized controlled trial

Background and Study Aim: Endoscopic papillary balloon dilation (EPBD) is assumed to have a theoretical advantage over endoscopic sphincterotomy (EST) in preserving sphincter of Oddi function because it does not involve cutting the biliary sphincter. Although attempts have been made to study the influence of EPBD and EST on sphincter of Oddi function, there is little agreement on this issue. In this study we used a method different from those described in previous reports to clarify whether EPBD or EST preserves sphincter of Oddi function better. Patients and Methods: 200 patients with bile duct stones who met the eligibility criteria were randomly assigned to EPBD (n = 104) or an EST (n = 96) group. Sphincter of Oddi function was estimated by measurement of the activity of pancreatic enzymes in the common bile duct (CBD). Pure bile was collected immediately before EPBD or EST, at 1 week and at 1 year after the procedure. We also statistically investigated 14 factors other than EPBD or EST that might have the potential to affect sphincter of Oddi function. Results: There was no significant difference between the baseline characteristics of the EPBD and EST groups. A total of 91 patients (46 in the EPBD group and 45 in the EST group) remained in the trial. Pure bile was collected from the CBD of 86 patients (43 EPBD and 43 EST) 1 week after the procedure. CBD stones were extracted successfully in all cases. Before the procedure, there were no significant differences in the levels of the five pancreatic enzymes between the EPBD and EST groups. At 1 week after the procedure, in both groups, there were significant increases in the levels of the five pancreatic enzymes. At 1 year after the procedure a complete series of pancreatic enzyme analyses was done in 33 patients (12 EPBD and 21 EST). There was no significant difference between the levels of the five pancreatic enzymes immediately before and 1 year after EPBD and EST. When the pancreatic enzyme levels of the two groups were directly compared, there was no significant difference at 1 year after the procedure, but the EPBD group had significantly higher levels at 1 week following the procedure. Conclusion: In this study it was found that in patients with CBD stones both EPBD and EST preserve sphincter of Oddi function.