The Surgery Scheduling Problem - A General Model

The term surgery scheduling is used about a variety of strategic, tactical and operational scheduling problems, many of which are critical to an efficient use of hospital resources. Our focus is on operational surgery scheduling problems, which are often NP-hard. The exact problem formulation varies substantially among hospitals, or even hospital departments. In addition, the level of detail vary between different planning situations, ranging from long term patient admission planning to a very detailed planning of the same day's surgeries. This diversity makes it difficult to design scheduling methods and software solutions that are applicable to a wide range of surgery scheduling problems, without extensive customization for each individual application. We approach this challenge by proposing a new generalised model for surgery scheduling problems. The problem can be seen as a rich extension to the resource-constrained project scheduling problem, and we present a structured overview of how our contribution relates to the existing project scheduling literature. We represent this problem by extending the classical disjunctive graph model developed for jobshop scheduling problems. To investigate the power of exact optimization methods in solving generalised surgery scheduling problems, we formulate this disjunctive model as a Mixed Integer Linear Program and solve it by means of a commercial solver. The results show that while it is not capable of solving realistic instances to optimality, the formulation produces good bounds, and promising results were found for interesting sub problem