Quantification of cognitive load and usability in 3 percutaneous posterior spine surgical workflows using functional...

Increase complexity in surgical workflows, with the introduction of digital interfaces and navigation, has the potential risk of introducing cognitive burden to the user. Understanding the effect of different surgical workflows on the user's mental load, as a way of supporting decision-making and design iterations for medical device development, is limited. The present study aimed to quantify differences in cognitive load during a demanding task in spine surgery (percutaneous pedicle screw placement) performed with three workflows with increasing complexity, from limited visual aid to the presence of a navigation system and digital interfaces. The methodology described in the present study included user performance data, through functional near infrared spectroscopy (fNIRS) data and user perception data, by means of Surgical Task Load Index (SURG-TLX) and a modified System Usability Survey (mSUS). Results demonstrated the feasibility of quantifying cognitive load through frontal lobe oxygenation metrics, demonstrating the workflow with the least amount of surgeon aid produced the highest and longer duration cognitive load, compared to workflows involving digital interfaces. The reduction in frontal lobe blood flow was supported by an overall perceived reduction in task complexity, overall demand, both mental and physical and situational stress. Results from this study suggests that the combination of fNIRS, SURG-TLX and mSUS provides a breadth of metrics describing changes in cognitive load for different surgical workflow complexities, which can support design input for medical device development. To our knowledge, this is the first study involving quantification of cognitive load in the surgical environment as a tool to support medical device development. This study can therefore be the starting point for a broad range of investigations to study the effect of medical device iteration on surgeons' cognitive load, system efficiency and usability and ultimately patient safety.