[Evaluation of the opening of the sphincter of Oddi]

Measurement of the activity of the sphincter of Oddi by the method of classical manometry did not reveal any significant difference before and after vagotomy. However, the existence after perfusion of residual pressure greater than initial pressure, suggests that a deformity of the duct during perfusion disturbs measurement of the opening of the sphincter. The mechanical properties of the duct were measured in vitro, as a first approximation it was suggested that the error due to a deformity of the duct, might be eliminated using several perfusion rates and calculating for each rate the opening R of the sphincter using the following formula: R equals (Perfusion pressure-Residual pressure) Flow rate. When the opening of the sphincter is calculated in this way, one may observe that vagotomy leads to definite reduction of the resistance of Oddi's sphincter.