Visual Control Strategies of Surgeons: A Novel Method of Establishing the Construct Validity of a Transurethral Resection of the Prostate Surgical Simulator
|Elizabeth Bright, Samuel J. Vine, Thomas Dutton, Mark R. Wilson, John S. McGrath
To examine novice and expert differences in visual control strategies while performing a virtual reality transurethral resection of the prostate (TURP) task and to determine if these differences could provide a novel method for assessing construct validity of the simulator.
Subjects and Methods
A total of 11 novices (no TURP experience) and 7 experts (>200 TURPs) completed a virtual reality prostate resection task on the TURPsim (Simbionix USA Corp, Cleveland, OH) while wearing an eye tracker (ASL, Bedford, MA). Performance parameters and the surgeon’s visual control strategy were measured and compared between the 2 groups.
Experts resected a greater percentage of prostate than novices (p < 0.01) and had less active diathermy time without tissue contact (p < 0.01). Experts adopted a target-locking visual strategy, employing fewer visual fixations (p < 0.05) with longer mean fixation duration (p < 0.005). With multiple learning trials, novices’ performance improved and the adoption of a more expertlike gaze strategy was observed.
Significant differences between experts and novices in both performance and visual control strategy were observed. The study of visual control strategies may be a useful adjunct, alongside measurements of motor performance, providing a novel method of assessing the construct validity of surgical simulators.