Recent evidence suggests that postoperative hyperamylasemia (POH) is a predictor of morbidity after pancreatectomy. This is based on the assumption that pancreatitis after pancreatectomy (PPAP) is a major trigger for the development of complications and is indicated by hyperamylasemia. Standardized prospective analysis and correlation with other laboratory parameters, hasn't been performed to date. Therefore the overall study aims are: * To prospectively evaluate the incidence and assess the clinical value of biochemical changes for the postoperative course. * To confirm and improve the definition and classification of postpancreatectomy acute pancreatitis (PPAP) of the International Study Group of Pancreatic Surgery (ISGPS) and to provide knowledge for effective early management of complications.