title: Hierarchical decomposition of laparoscopic surgery: a human factors approach to investigating the operating room environment.
abstract: Hierarchical decomposition of complex behaviour and systems is a valuable research methodology from human factors and information-processing psychology that can be applied to laparoscopic surgery. This article describes results of research on surgeons performing several different laparoscopic procedures, conducted in Vancouver, Canada 1995&#150;98. Through top-down analyses of surgical procedures and bottom-up analyses of tool motions, results included detailed decomposition of the procedures through surgical steps, sub-steps, tasks, sub-tasks and tool motions. Analyses at all levels provided valuable information. In addition to specific surgeon- and technology-related observations, such as the effect of dividing the short gastrics on performance of Nissen fundoplication, gaze patterns of surgeons and factors related to patient safety were analysed. The hierarchical decomposition approach can be extended to other aspects of the complex system that consists of the surgeon and operating room team, the technologies and the operating room environment. Other frameworks for assessment are also considered.