Abstract
For a surgical procedure, the instruments a surgeon has requested are grouped into multiple containers that are referred to as trays. Empirical studies have shown that a large percentage of the instruments that are cleaned and sterilized after a procedure were not even used. In addition, each tray needs to be frequently lifted, which puts perioperative nurses and technicians (PNTs) at risk of developing work-related musculoskeletal disorders (WRMSDs), especially when the trays are overweight. The problem of grouping sterile instruments into trays and determining the tray types for each surgeon and procedure is an NP-hard problem known as the tray optimization problem (TOP). We have developed a bi-objective mathematical model to solve the TOP with the aim of concurrently improving the utilization rate of the instruments and minimizing the tray types required for each procedure. We have established a novel heuristic using an iterated local search (ILS) to quickly and efficiently solve the problem. Computational results over historical data show that the designed ILS is superior to known exact methods. Finally, we have shown to what extent changing the weight limit of trays may have implications on the number of tray types and utilization rate of instruments within trays.