Challenges in planning and initiating a randomized clinical study of sphincter of Oddi dysfunction

Peter B. Cotton, Valerie Durkalski, Kyle B. Orrell, Olga Brawman-Mintzer, Douglas A. Drossman, C. Mel Wilcox, Patrick D. Mauldin, Grace H. Elta, Paul R. Tarnasky, Evan L. Fogel, Sanjay B. Jagganath, Richard A. Kozarek, Martin L. Freeman, Joseph Romagnuolo, Patricia R. Robuck