Background: With the popularity of endoscopic sphincterotomy (EST), long-term complications of EST are receiving increasingly more attention, but the mechanisms have not been sufficiently elucidated.
Aim: This study aimed to investigate the relationship between long-term complications of EST and sphincter of Oddi (SO) function and other associated risk factors.
Patients and methods: A total of 139 patients with choledocholithiasis who had undergone EST were consecutively enrolled, and divided into two groups: patients with long-term complications (LC group) and patients without complications (control group). Before and 2 years after EST, sphincter of Oddi manometry and bacterial culture were performed to evaluate the functional change in SO and infection of the biliary duct.
Results: With an average follow-up duration of 45.8 months, 25 (18.0%) patients developed long-term complications (LC group). Compared with before EST, contraction amplitude and frequency of SO in both groups were markedly reduced after EST, but the changes were not significantly different between the two groups (P>0.05). The rates of bacterial infection in the biliary tract increased significantly in the LC group compared with the control group after EST: 57.1% (12/21) versus 32.7% (35/107), respectively (P=0.034), although these were similar before EST in both the groups. Logistic regression analysis showed that cholecystolithiasis, common bile duct diameter 15 mm or more, and maximum stone diameter 15 mm or more were major risk factors for long-term complications.
Conclusion: Weakened SO function is not a decisive factor for long-term complications of EST, which were mainly influenced by biliary tract infection and high risk factors of the biliary tract.