Post Roux-en-Y Gastric Bypass Biliary Dilation: Natural Process or Significant Entity?

Background: Changes in the biliary system after gastric bypass are not well defined. Dilation may be normal or due to biliary tract pathology. The purpose of this study is to review patients who underwent imaging of their biliary system both before and after Roux-en-Y gastric bypass in an effort to elucidate the effect this operation has on hepatic duct diameter. Methods: Patients with imaging both before and at least 3 months after gastric bypass were analyzed. Hepatic duct was measured at the level of the porta hepatis to determine interval changes. Results: Thirty-three patients had postoperative imaging at least 3 months following gastric bypass. Mean hepatic duct diameter was 5.2 ± 2 and 7.1 ± 2.6 mm preoperatively and postoperatively, respectively (p & 0.01). Patients with prior cholecystectomy had hepatic duct diameters of 7.9 ± 1.3 and 9.5 ± 3.5 mm preoperatively and postoperatively, respectively (p = 0. 3). Patients who had not previously undergone cholecystectomy had hepatic duct diameters of 4.3 ± 1.1 and 6.4 ± 1.8 mm preoperatively and postoperatively, respectively (p < 0.01). Conclusions: Hepatic duct diameter increases after Roux-en-Y gastric bypass. A better understanding of this phenomenon may limit the need for further work-up in patients with incidentally detected biliary dilation.