Development of a Prospective Method for Rating Surgical Task Workloads

Surgical adverse events can have serious consequences for patients ranging from temporary injuries to death. Thereby, up to 40% of surgical adverse events are preventable and over 60% of causal factors were found to be linked to human factors. To improve surgical performance and safety, computer-assisted surgical (CAS) systems can be used to reduce excessive workloads. This paper presents a method for prospective assessment of surgical task workloads. S-TAWL, developed with the support of a senior neurosurgeon and a usability engineer, consists of three parts: surgical task decomposition, workload rating scale application, and performance shaping factors characterization. For the proposed rating scales, composed of reference operators, relative workloads were determined by 11 neurosurgeons through pairwise comparison. Afterwards, one senior neurosurgeon, not involved in method development, analysed workloads of four common surgical tasks with the proposed method S-TAWL and a reference workload rating method Surg-TLX. Qualitatively, S-TAWL provides more detailed information about workloads with respect to human resources compared to the reference method. Quantitatively, however, the reliability of the results is still limited, as indicated by high standard deviations. Further research is needed to develop reliable and valid rating scales, compute compound workloads and identify overloads. Incorporating quantitative workload assessment in prospective human performance analysis will provide valuable information for targeted model-based design of assistance systems, supporting safe and successful surgery in the future.