Objective of the Study
Minimally invasive surgery (MIS) offers clear benefits to patients yet places increased demands on the surgeon. This is in part due to a lack of depth perception and haptic feedback and poor instrument ergonomics. Robotic assisted MIS aims to address these challenges. An example of this is Gaze-Contingent Motor Channelling (GCMC). GCMC seeks to enhance surgical dexterity by constraining the master-slave manipulation based on eyetracking information. Whilst operating with GCMC, subject gaze behaviour is extracted in real time and used to constrain the surgeon’s instrument to their fixation point, thus improving accuracy1.
It is imperative that emergent surgical technology is scrutinised not only with respect to its effect on performance, but also its effect on the surgeon (ergonomics). Recently, the concept of neuroergonomics has been introduced as the study of the brain behaviour at work2. It has been applied to assessing air traffic control, car driving and assessing mental workload, but has not yet been applied to surgery. Theoretically, it is possible to use the brain to assess the effect due to performance of a surgical task, thus determining whether interventions are likely to be beneficial or not.
The aim of this study is to assess the impact of GCMC on both the cognitive demands of the user and the effect on performance. A neuroergonomic paradigm is employed to investigate this. It is hypothesised that GCMC will improve performance and increase the attentional demands of the surgeon.
Methods and procedures
The task consists of using a virtual tool, controlled with a haptic device, to track a moving target on a simulated beating heart. Subjects perform the task with and without GCMC and are randomised as to which is performed first. Functional near infrared spectroscopy (fNIRS) is used to assess changes in prefrontal cortical haemodynamics as a surrogate for task induced cortical activity. A block design was employed with subjects performing the task for 20 seconds followed by 30 seconds rest, repeated 5 times. Accuracy was determined by the distance from the tool tip to the target.
Results
21 right-handed novices completed the task with and without GCMC. Subjects were more accurate with GCMC assistance versus unassisted performance (p=0.008). Greater changes in cortical haemodynamics were observed with GCMC, with 8 fNIRS channels demonstrating statistically significant activity (?=5%) compared to zero channels without GCMC. The activation occurred in the medial prefrontal cortex.
Conclusion
It has been demonstrated that GCMC enhances novice performance and that this requires greater medial prefrontal cortical activity. It is possible that in using GCMC, the user focussed more on the quality and accuracy of movement. In order to achieve this, the medial prefrontal cortex which is involved in performance monitoring, is recruited to a greater extent. This work demonstrates how changes in brain behaviour can be used to assess the impact of novel surgical technology.
1 – Mylonas G.P.et al. MICCAI. 2008:11, 676-683
2- Parasuraman R.Theoretical Issues inErgonomics Science.20034, 5-20
Session: Podium Presentation
Program Number: S050