The investigators prospectively collected in an electronic database preoperative, intraoperative and outcome data of 700 patients undergoing PD in our Institution from 2002 to 2010. The investigators used a multivariate logistic regression analysis to create a new score to predict severe complications defined as Clavien-Dindo classification III, IV and V. The score was developed using a random two-thirds of the population (469 patients), and was then validated and calibrated in the remaining third of the patients (231).