Sphincter of Oddi Manometry: Reproducibility of Measurements and Effect of Sphincterotomy in the EPISOD Study

BACKGROUND/AIMS The reproducibility of sphincter of Oddi manometry (SOM) measurements and results of SOM after sphincterotomy has not been studied sufficiently. The aim of our study is to evaluate the reproducibility of SOM and completeness of sphincter ablation. METHODS The recently published Evaluating Predictors and Interventions in sphincter of Oddi dysfunction (EPISOD) study included 214 subjects with post-cholecystectomy pain, and fit the criteria of sphincter of Oddi dysfunction type III. They were randomized into 3 arms, irrespective of manometric findings: sham (no sphincterotomy), biliary sphincterotomy, and dual (biliary and pancreatic). Thirty-eight subjects had both biliary and pancreatic manometries performed twice, at baseline and at repeat endoscopic retrograde cholangiopancreatography after 1-11 months. Sham arm was examined to assess the reproducibility of manometry, and the treatment arms to assess whether the sphincterotomies were complete (elevated pressures were normalized). RESULTS Biliary and pancreatic measurements were reproduced in 7/14 (50%) untreated subjects. All 12 patients with initially elevated biliary pressures in biliary and dual sphincterotomy groups normalized after biliary sphincterotomy. However, 2 of 8 subjects with elevated pancreatic pressures in the dual sphincterotomy group remained abnormal after pancreatic sphincterotomy. Paradoxically, normal biliary pressures became abnormal in 1 of 15 subjects after biliary sphincterotomy, and normal pancreatic pressures became abnormal in 5 of 15 patients after biliary sphincterotomy, and in 1 of 9 after pancreatic sphincterotomy. CONCLUSIONS Our data suggest that SOM measurements are poorly reproducible, and question whether we could adequately perform pancreatic sphincterotomy.