A new distensibility technique to measure sphincter of Oddi function

Abstract Background Evaluation of the biliary tract is important in physiological, pathophysiological, and clinical studies. Although the sphincter of Oddi (SO) can be evaluated with manometry, this technique has several limitations. This may explain the difficulties in identifying pathophysiological mechanisms for dysfunction of the SO and in identifying patients who may benefit from certain therapies. To encompass problems with manometry, methods such as the functional lumen imaging probe (FLIP) technique have been developed to study GI sphincters. This study set about miniaturising the FLIP probe and validating it for measurements in the SO. In order to get a better physiological understanding of the SO the aims were to show the sphincter profile in vivo and motility patterns of SO in pilot studies using volunteers that were experiencing biliary type pain but had normal SO manometry. Methods The SO probe was constructed to measure eight cross-sectional areas (CSA) along a length of 25 mm inside a saline-filled bag. To validate the technique for profiling the SO, six perspex cylinders with different CSAs were measured nine times to assess reproducibility and accuracy. Key Results Reproducibility and accuracy for these measurements were good. The probe performed well in bench tests and was therefore tested in four humans. The data indicated that it was possible to make distensions in the human SO and that a geometric sphincter profile could be obtained. Conclusions & Inferences The probe will in future studies be tested for diagnostic purposes related to sphincter of Oddi diseases.