  Purpose: We propose a mathematical framework for quantitative analysis
weighting the impact of heterogeneous components of a surgery. While
multi-level approaches, surgical process modeling and other workflow analysis
methods exist, this is to our knowledge the first quantitative approach.
Methods: Inspired by the group decision making problem from the field of
operational research, we define event impact factors, which combine independent
and very diverse low-level functions. This allows us to rate surgical events by
their importance. Results: We conducted surveys with 4 surgeons to determine
the importance of roles, phases and their combinations within a laparoscopic
cholecystectomy. Applying this data on a recorded surgery, we showed that it is
possible to define a quantitative measure for deciding on acception or
rejection of calls to different roles and at different phases of surgery.
Conclusions: This methodology allows us to use components such as expertise and
role of the surgical staff and other aspects of a given surgery in order to
quantitatively analyze and evaluate events, actions, user interfaces or
procedures.
