3. This is a pilot exploratory study, and the working hypothesis may prove wrong; it is therefore critical to limit the initial costs in accordance with the study budget and availability of Dr Hutter's expertise. If our hypothesis is supported by the initial results, we may proceed with additional investigations and a more elaborated research project with adequate funding resources.¨ For these reasons, we will restrict our research to three SHCS centers. Zurich, Geneva and Lausanne were chosen essentially based on existing relationship between the visceral surgery units.