RESUMO
OBJECTIVE: 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. RESULTS: 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. CONCLUSION: 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.
Assuntos
Simulação por Computador/normas , Ressecção Transuretral da Próstata/normas , Interface Usuário-Computador , Humanos , MasculinoRESUMO
BACKGROUND: Although virtual reality (VR) simulators serve an important role in the training and assessment of surgeons, they need to be evaluated for evidence of validity. Eye-tracking technology and measures of visual control have been used as an adjunct to the performance parameters produced by VR simulators to help in objectively establishing the construct validity (experts vs. novices) of VR simulators. However, determining the extent to which VR simulators represent the real procedure and environment (content validity) has largely been a subjective process undertaken by experienced surgeons. This study aimed to examine the content validity of a VR transurethral resection of the prostate (TURP) simulator by comparing visual control metrics taken during simulated and real TURP procedures. METHODS: Eye-tracking data were collected from seven surgeons performing 14 simulated TURP operations and three surgeons performing 15 real TURP operations on live patients. The data were analyzed offline, and visual control metrics (number and duration of fixations, percentage of time the surgeons fixated on the screen) were calculated. RESULTS: The surgeons displayed more fixations of a shorter duration and spent less time fixating on the video monitor during the real TURP than during the simulated TURP. This could have been due to (1) the increased complexity of the operating room (OR) environment (2) the decreased quality of the image of the urethra and associated anatomy (compared with the VR simulator), or (3) the impairment of visual attentional control due to the increased levels of stress likely experienced in the OR. CONCLUSIONS: The findings suggest that the complexity of the environment surrounding VR simulators needs to be considered in the design of effective simulated training curricula. The study also provides support for the use of eye-tracking technology to assess the content validity of simulation and to examine psychomotor processes during live operations.